Group items tagged

Ki-67 is also expressed at low levels (<3 % of cells) in ER-negative cells, but not in ER-positive cells

A meta-analysis involving 12,155 patients demonstrated that the Ki-67 positivity confers a higher risk of recurrence and a worse survival rate in patients with early breast cancer.

high levels of Ki-67 are associated with worse prognoses

Ki-67 was associated with worse survival rates

associated with proliferation

higher tumor stages and higher nodal status were associated with higher Ki-67 quartiles indicating that the more aggressive the tumor is the higher is the percentage of cells positively stained for Ki-67

Previous studies were able to demonstrate that a prognostic model, the IHC 4 score, using ER, PR, HER2, and Ki-67 provides similar prognostic information to that in the 21-gene Genomic Health recurrence score

ER status has been largely identified as being inversely correlated with Ki-67, with the higher rates of ER positivity shown in the lowest proliferating tumors

high levels of Ki-67 are associated with HER2/-neu positivity according to former studies

higher values of Ki-67-labeling index were associated with adverse prognostic factors

Ki-67-labeling index was associated with larger tumors, higher tumor grade, peritumoral vascular invasion, and HER-2 positivity

testosterone therapy causes a shift in the skeletal muscle of CHF patients toward a higher concentration of type I muscle fibers

Testosterone replacement therapy has also been shown to improve the homeostatic model of insulin resistance and hemoglobin A1c in diabetics26,68–69 and to lower the BMI in obese patients.

Lower levels of endogenous testosterone have been associated with longer duration of the QTc interval

testosterone replacement has been shown to shorten the QTc interval

negative correlation has been demonstrated between endogenous testosterone levels and IMT of the carotid arteries, abdominal aorta, and thoracic aorta

These findings suggest that men with lower levels of endogenous testosterone may be at a higher risk of developing atherosclerosis.

Current guidelines from the Endocrine Society make no recommendations on whether patients with heart disease should be screened for hypogonadism and do not recommend supplementing patients with heart disease to improve survival.

The Massachusetts Male Aging Study also projects ≈481 000 new cases of hypogonadism annually in US men within the same age group

since 1993 prescriptions for testosterone, regardless of the formulation, have increased nearly 500%

Testosterone levels are lower in patients with chronic illnesses such as end‐stage renal disease, human immunodeficiency virus, chronic obstructive pulmonary disease, type 2 diabetes mellitus (T2DM), obesity, and several genetic conditions such as Klinefelter syndrome

A growing body of evidence suggests that men with lower levels of endogenous testosterone are more prone to develop CAD during their lifetimes

There are 2 major potential confounding factors that the older studies generally failed to account for. These factors are the subfraction of testosterone used to perform the analysis and the method used to account for subclinical CAD.

The biologically inactive form of testosterone is tightly bound to SHBG and is therefore unable to bind to androgen receptors

The biologically inactive fraction of testosterone comprises nearly 68% of the total testosterone in human serum

The biologically active subfraction of testosterone, also referred to as bioavailable testosterone, is either loosely bound to albumin or circulates freely in the blood, the latter referred to as free testosterone

It is estimated that ≈30% of total serum testosterone is bound to albumin, whereas the remaining 1% to 3% circulates as free testosterone

it can be argued that using the biologically active form of testosterone to evaluate the association with CAD will produce the most reliable results

English et al14 found statistically significant lower levels of bioavailable testosterone, free testosterone, and free androgen index in patients with catheterization‐proven CAD compared with controls with normal coronary arteries

patients with catheterization‐proven CAD had statistically significant lower levels of bioavailable testosterone

In conclusion, existing evidence suggests that men with CAD have lower levels of endogenous testosterone,13–18 and more specifically lower levels of bioavailable testosterone

low testosterone levels are associated with risk factors for CAD such as T2DM25–26 and obesity

In a meta‐analysis of these 7 population‐based studies, Araujo et al41 showed a trend toward increased cardiovascular mortality associated with lower levels of total testosterone, but statistical significance was not achieved (RR, 1.25

the authors showed that a decrease of 2.1 standard deviations in levels of total testosterone was associated with a 25% increase in the risk of cardiovascular mortality

the relative risk of all‐cause mortality in men with lower levels of total testosterone was calculated to be 1.35

higher risk of cardiovascular mortality is associated with lower levels of bioavailable testosterone

Existing evidence seems to suggest that lower levels of endogenous testosterone are associated with higher rates of all‐cause mortality and cardiovascular mortality

studies have shown that lower levels of endogenous bioavailable testosterone are associated with higher rates of all‐cause and cardiovascular mortality

It may be possible that using bioavailable testosterone to perform mortality analysis will yield more accurate results because it prevents the biologically inactive subfraction of testosterone from playing a potential confounding role in the analysis

The earliest published material on this matter dates to the late 1930s

the concept that testosterone replacement therapy improves angina has yet to be proven wrong

In more recent studies, 3 randomized, placebo‐controlled trials demonstrated that administration of testosterone improves myocardial ischemia in men with CAD

The improvement in myocardial ischemia was shown to occur in response to both acute and chronic testosterone therapy and seemed to be independent of whether an intravenous or transdermal formulation of testosterone was used.

testosterone had no effect on endothelial nitric oxide activity

There is growing evidence from in vivo animal models and in vitro models that testosterone induces coronary vasodilation by modulating the activity of ion channels, such as potassium and calcium channels, on the surface of vascular smooth muscle cells

Experimental studies suggest that the most likely mechanism of action for testosterone on vascular smooth muscle cells is via modulation of action of non‐ATP‐sensitive potassium ion channels, calcium‐activated potassium ion channels, voltage‐sensitive potassium ion channels, and finally L‐type calcium ion channels

Corona et al confirmed those results by demonstrating that not only total testosterone levels are lower among diabetics, but also the levels of free testosterone and SHBG are lower in diabetic patients

Laaksonen et al65 followed 702 Finnish men for 11 years and demonstrated that men in the lowest quartile of total testosterone, free testosterone, and SHBG were more likely to develop T2DM and metabolic syndrome.

Vikan et al followed 1454 Swedish men for 11 years and discovered that men in the highest quartile of total testosterone were significantly less likely to develop T2DM

authors demonstrated a statistically significant increase in the incidence of T2DM in subjects receiving gonadotropin‐releasing hormone antagonist therapy. In addition, a significant increase in the rate of myocardial infarction, stroke, sudden cardiac death, and development of cardiovascular disease was noted in patients receiving antiandrogen therapy.67

Several authors have demonstrated that the administration of testosterone in diabetic men improves the homeostatic model of insulin resistance, hemoglobin A1c, and fasting plasma glucose

Existing evidence strongly suggests that the levels of total and free testosterone are lower among diabetic patients compared with those in nondiabetics

insulin seems to be acting as a stimulant for the hypothalamus to secret gonadotropin‐releasing hormone, which consequently results in increased testosterone production. It can be argued that decreased stimulation of the hypothalamus in diabetics secondary to insulin deficiency could result in hypogonadotropic hypogonadism

BMI has been shown to be inversely associated with testosterone levels

This interaction may be a result of the promotion of lipolysis in abdominal adipose tissue by testosterone, which may in turn cause reduced abdominal adiposity. On the other hand, given that adipose tissue has a higher concentration of the enzyme aromatase, it could be that increased adipose tissue results in more testosterone being converted to estrogen, thereby causing hypogonadism. Third, increased abdominal obesity may cause reduced testosterone secretion by negatively affecting the hypothalamus‐pituitary‐testicular axis. Finally, testosterone may be the key factor in activating the enzyme 11‐hydroxysteroid dehydrogenase in adipose tissue, which transforms glucocorticoids into their inactive form.

increasing age may alter the association between testosterone and CRP. Another possible explanation for the association between testosterone level and CRP is central obesity and waist circumference

Bai et al have provided convincing evidence that testosterone might be able to shorten the QTc interval by augmenting the activity of slowly activating delayed rectifier potassium channels while simultaneously slowing the activity of L‐type calcium channels

consistent evidence that supplemental testosterone shortens the QTc interval.

Intima‐media thickness (IMT) of the carotid artery is considered a marker for preclinical atherosclerosis

Studies have shown that levels of endogenous testosterone are inversely associated with IMT of the carotid artery,126–128,32,129–130 as well as both the thoracic134 and the abdominal aorta

1 study has demonstrated that lower levels of free testosterone are associated with accelerated progression of carotid artery IMT

another study has reported that decreased levels of total and bioavailable testosterone are associated with progression of atherosclerosis in the abdominal aorta

These findings suggest that normal physiologic testosterone levels may help to protect men from the development of atherosclerosis

Czesla et al successfully demonstrated that the muscle specimens that were exposed to metenolone had a significant shift in their composition toward type I muscle fibers

Type I muscle fibers, also known as slow‐twitch or oxidative fibers, are associated with enhanced strength and physical capability

It has been shown that those with advanced CHF have a higher percentage of type II muscle fibers, based on muscle biopsy

Studies have shown that men with CHF suffer from reduced levels of total and free testosterone.137 It has also been shown that reduced testosterone levels in men with CHF portends a poor prognosis and is associated with increased CHF mortality.138 Reduced testosterone has also been shown to correlate negatively with exercise capacity in CHF patients.

Testosterone replacement therapy has been shown to significantly improve exercise capacity, without affecting LVEF

the results of the 3 meta‐analyses seem to indicate that testosterone replacement therapy does not cause an increase in the rate of adverse cardiovascular events

Data from 3 meta‐analyses seem to contradict the commonly held belief that testosterone administration may increase the risk of developing prostate cancer

One meta‐analysis reported an increase in all prostate‐related adverse events with testosterone administration.146 However, when each prostate‐related event, including prostate cancer and a rise in PSA, was analyzed separately, no differences were observed between the testosterone group and the placebo group

the existing data from the 3 meta‐analyses seem to indicate that testosterone replacement therapy does not increase the risk of adverse cardiovascular events

the authors correctly point out the weaknesses of their study which include retrospective study design and lack of randomization, small sample size at extremes of follow‐up, lack of outcome validation by chart review and poor generalizability of the results given that only male veterans with CAD were included in this study

the studies that failed to find an association between testosterone and CRP used an older population group

low testosterone may influence the severity of CAD by adversely affecting the mediators of the inflammatory response such as high‐sensitivity C‐reactive protein, interleukin‐6, and tumor necrosis factor–α

An association between testosterone and WBC count was not observed

These findings are consistent with the hypothesis that in men higher androgen concentration is anti-inflammatory, and higher estrogen concentration is pro-inflammatory.

the probability of elevated CRP concentrations (≥ 3 mg/L) decreased with higher total and calculated free testosterone concentrations, while the probability increased with higher total and calculated free estradiol concentrations

there is ample evidence supporting the immunosuppressive effect of androgens

The incidence of autoimmune diseases is higher in androgen-deficient men

Studies have shown that the induction of hypogonadism in older men is followed by a significant increase in IL-6 concentrations (Khosla et al. 2002), a potent stimulator of inflammation, and that activation of the androgen receptor exerts a direct anti-inflammatory effect

It has been suggested that the mechanisms for the immunosuppressive effect of androgens could be either a direct effect on the expression of inflammatory genes (Bellido et al. 1995; Asirvatham et al. 2006), or an indirect effect through inhibition of nuclear factor-kB activation

Estradiol is the major biologically active estrogen, and about 80% is formed in adult men from the aromatization of testosterone primarily in the adipose tissue

estrogen can stimulate the transcription factor C/EBP-β, which is involved in CRP transcription

Most prior cross-sectional studies have observed inverse associations between androgen concentrations and inflammatory biomarkers

A recent study in Chinese men showed that lower concentrations of total and calculated free testosterone were associated with higher CRP concentration

Data from the Boston Area Community Health Survey also reported inverse associations between testosterone and CRP concentrations

Total testosterone was inversely associated with WBC count (Tang et al. 2007; Schneider et al. 2009; Brand et al. 2012), but calculated free testosterone was not associated with WBC

The first trial found a decrease in CRP, interleukin-1β (IL-1β), and tumor necrosis factor-α (TNFα) but no changes in IL-6 and IL-10 concentrations between the active treatment and placebo arms

the majority of studies in the literature have not observed statistically significant associations between estradiol and inflammatory biomarkers in men, although several of them observed point estimates in the positive direction

total testosterone and estradiol compete for binding to SHBG, and seem to have opposite effects on the concentration of inflammatory biomarkers

A small randomized controlled trial of estrogen replacement therapy in prostate cancer patients showed an increase in CRP in the active treatment group versus the comparator group

Obese men are known to have lower androgen concentrations compared to their normal-weight counterparts

The strongest suggestion of an interaction was the inverse association between androstanediol glucuronide and CRP concentrations in obese participants, while the association was positive in the non-obese

A recent Chinese cross-sectional study observed stronger inverse associations between total testosterone and CRP concentrations in individuals with a BMI of 27.5 kg/m2 or greater

our results suggest that total and calculated free testosterone are modestly inversely associated with CRP concentrations, and that total and calculated free estradiol are modestly positively associated with CRP and WBC

The CHALICE cohort of 404 individuals aged 50 years had an average vitamin C intake of ~110 mg/day, which should provide adequate plasma concentrations [14]. Despite this, a significant proportion of the participants had inadequate plasma vitamin C status

inadequate plasma vitamin C concentrations (i.e., <50 µmol/L)

adequate plasma levels (i.e., >50 µmol/L)

Higher plasma vitamin C status was associated with lower weight, BMI and waist circumference

plasma vitamin C was negatively associated with blood triglycerides, HbA1c and insulin, and positively associated with HDL levels.

No correlation was found between plasma vitamin C and the two indicators of heart health; blood pressure and cardiovascular risk score.

2.4% of 50-year-olds were deficient in vitamin C (i.e., <11 µmol/L)

hypovitaminosis C (i.e., <23 µmol/L)

A high proportion (63%) of our participants had inadequate plasma vitamin C concentrations (i.e., <50 µmol/L)

The association of low vitamin C with obesity in this study replicates results in the literature [35,40,41,42,43,44], and it is apparent that individuals with higher weight require higher intakes of vitamin C to reach adequate vitamin C status

higher plasma vitamin C status is associated with lower circulating levels of blood triglycerides, insulin and HbA1c

A role for vitamin C in the prevention or management of diabetes and/or metabolic syndrome has been suggested

In this study, we also demonstrate lower levels of mild cognitive impairment in those with high vitamin C status

The odds of mild cognitive impairment were twice as high for those below 23 μmol/L plasma vitamin C concentration.

Vitamin C is present at very high concentrations in the brain

animal models have shown that the brain is the last organ to be depleted of the vitamin during prolonged deficiency

A recent animal study has shown that moderate vitamin C deficiency may play a role in accelerating amyloid plaque accumulation in Alzheimer’s disease

Patients with higher inflammation or tumor burdens, as measured by CRP levels or tumor antigen levels, tend to show lower peak plasma ascorbate levels after IVC.

Patients with metastatic tumors tend to achieve lower post infusion plasma ascorbate levels than those with localized tumors.

Meta-analyses of clinical studies involving cancer and vitamins also conclude that antioxidant supplementation does not interfere with the efficacy of chemotherapeutic regiments

Most of the prostate cancer patients studied, 75±19% (95% confidence), showed reductions in PSA levels during the course of their IVC therapy

Laboratory studies suggest that, at high concentrations, ascorbate does not interfere with chemotherapy or irradiation and may enhance efficacy in some situations

Cameron and Pauling observed fourfold survival times in terminal cancer patients treated with intravenous ascorbate infusions followed by oral supplementation

The inflammatory microenvironment of cancer cells leads to increasing oxidative stress, which apparently depletes vitamin C, resulting in lower plasma ascorbate concentrations in blood samples post IVC infusion. Another explanation for this finding may be that cancers are themselves more metabolically active in their uptake of vitamin C, causing subjects to absorb more of the vitamin, and as a results show lower plasma ascorbate concentrations in blood post IVC infusion.

patients with severely elevated CRP levels attain plasma ascorbate concentrations after IVC infusions that are only 65% of those attained for subjects with normal CRP levels

The finding of decreased plasma ascorbate levels in cancer patients may relate to the molecular structure of ascorbic acid; in particular, the similarity of its oxidized form, dihydroascorbic acid, to glucose

Since tumor have increased requirement for glucose [67], transport of dehydroascorbate into the cancer cells via glucose transport molecules and ascorbate through sodium-dependent transporter may be elevated

Increased accumulation of ascorbic acid in the tumor site was supported by measurements of the level of ascorbic acid in tumors in animal experiments

patients with advanced malignancies may have lower level of ascorbic acid in tissue, creating a higher demand for the vitamin C

IVC therapy appears to reduce CRP levels in cancer patients.

CRP concentrations directly correlate with disease activity in many cases and can contribute to disease progression through a range of pro-inflammatory properties.

Being an exquisitely sensitive marker of systemic inflammation and tissue damage, CRP is very useful in screening for organic disease and monitoring treatment responses

ncreases in CRP concentrations have been associated with poorer prognosis of survival in cancer patients, particularly with advance disease independent of tumor stage

Regarding inflammation, 73±13% of subjects (95% confidence) showed a reduction in CRP levels during therapy. This was an even more dramatic 86±13% (95% confidence) in subjects who started therapy with CRP levels above 10 mg/L

patients treated by IVC with follow-up several year showed that suppression of inflammation in cancer patients by high-dose IVC is feasible and potentially beneficial

Inflammation is a marker of high cancer risk, and poor treatment outcome

The subjects with highly elevated CRP concentrations have a three-fold elevation “all-cause” mortality risk and a twenty-eight fold increase in cancer mortality risk

cancer patients may need higher doses to achieve a given plasma concentration.

patients with lower vitamin C levels may see more distribution of intravenously administered ascorbate into tissues and thus attain less in plasma.

When treating patients with IVC, the first treatment likely serves to replenish depleted tissue stores, if those subjects were vitamin C deficient at the beginning of the treatment. Then, in subsequent treatments, with increasing doses, higher plasma concentrations can be attained. On-going treatments serve to progressively reduce oxidative stress in cancer patients.

large doses given intravenously may result in maximum plasma concentrations of roughly 30 mM, a level that has been shown to be sufficient for preferential cytotoxicity against cancer cells

oral intake of vitamin C exceeded 200 mg administered once daily, it was difficult to increase plasma and tissue concentrations above roughly 200 μM.

Researchers tried to examine whether serum total or free testosterone would be a better/more reliable choice when studying the effect of testosterone. The results were mixed. Some reported significant associations of both serum total and free testosterone level with clinical parameters25, whereas others reported that only serum free testosterone26 or only serum total testosterone6 showed significant associations.

−0.124 nmol/L/year in serum total testosterone

In experimental studies, androgen receptor knockout mice developed significant insulin resistance rapidly

In mouse models, testosterone promoted differentiation of pluripotent stem cells to the myogenic lineage

testosterone decreased insulin resistance by enhancing catecholamine induced lipolysis in vitro, and reducing lipoprotein lipase activity and triglyceride uptake in human abdominal tissue in vivo

by promoting lipolysis and myogenesis, testosterone might lead to improved insulin resistance

testosterone regulated skeletal muscle genes involved in glucose metabolism that led to decreased systemic insulin resistance

In the liver, hepatic androgen receptor signaling inhibited development of insulin resistance in mice

independent and inverse association of testosterone with hepatic steatosis shown in a cross-sectional study carried out in humans

In short, androgen improves insulin resistance by changing body composition and reducing body fat.

Although a low serum testosterone level could contribute to the development of obesity and type 2 diabetes through changes in body composition, obesity might also alter the metabolism of testosterone

In obese men, the peripheral conversion from testosterone to estrogen could attenuate the amplitude of luteinizing hormone pulses and centrally inhibit testosterone production

leptin, an adipokine, has been shown to be inversely correlated with serum testosterone level in men

Leydig cells expressed leptin receptors and leptin has been shown to inhibit testosterone secretion, suggesting a role of obesity and leptin in the pathogenesis of low testosterone

Baltimore Longitudinal Study of Aging (BLSA) cohort made up of 3,565 middle-class, mostly Caucasian men from the USA, the incidence of low serum total testosterone increased from approximately 20% of men aged over 60 years, 30% over 70 years, to 50% over 80 years-of-age

30–44% sex hormone binding globulin (SHBG)-bound testosterone and 54–68% albumin-bound testosterone

As the binding of testosterone to albumin is non-specific and therefore not tight, the sum of free and albumin-bound testosterone is named bioavailable testosterone, which reflects the hormone available at the cellular level

Serum total testosterone is composed of 0.5–3.0% of free testosterone unbound to plasma proteins

alterations in SHBG concentration might affect total serum testosterone level without altering free or bioavailable testosterone

listed in Table​T

A significant, independent and longitudinal effect of age on testosterone has been observed with an average change of −0.124 nmol/L/year in serum total testosterone28. The same trend has been shown in Europe and Australia

Asian men residing in HK and Japan, but not those living in the USA, had 20% higher serum total testosterone than in Caucasians living in the USA, as shown in a large multinational observational prospective cohort of the Osteoporotic Fractures in Men Study

subjects with chronic diseases consistently had a 10–15% lower level compared with age-matched healthy subjects

In Caucasians, the mean serum total testosterone level for men in large epidemiological studies has been reported to range from 15.1 to 16.6 nmol/L

Asians, higher values, ranging from 18.1 to 19.1 nmol/L, were seen in Korea and Japan

Chinese middle-aged men reported a similar mean serum testosterone level of 17.1 nmol/L in 179 men who had a family history of type 2 diabetes and 17.8 nmol/L in 128 men who had no family history of type 2 diabetes

The reduction of total testosterone was 0.4% per year in both groups

HK involving a cohort of 1,489 community-dwelling men with a mean age of 72 years, a mean serum total testosterone of 19.0 nmol/L was reported

pro-inflammatory factors, such as tumor necrosis factor-α in the testes, could locally inhibit testosterone biosynthesis in Leydig cells47, and testosterone treatment in men was shown to reduce the level of tumor necrosis factor-α

In Asians, a genetic deletion polymorphism of uridine diphosphate-glucuronosyltransferase UGT2B17 was associated with reduced androgen glucuronidation. This resulted in higher level of active androgen in Asians as compared to Caucasians, as Caucasians' androgen would be glucuronidated into inactive forms faster.

Compared with Caucasians, the frequency of this deletion polymorphism of UGT2B17 was 22-fold higher in Asian subjects

Other researchers have suggested that environmental, but not genetic, factors influenced serum total testosterone

The basal and ligand-induced activity of the AR is inversely associated with the length of the CAG repeat chain

In the European Male Aging Study, increased estrogen/androgen ratio in association with longer AR CAG repeat was observed

a smaller number of AR CAG repeat had been shown to be associated with benign prostate hypertrophy and faster prostate growth during testosterone treatment

In India, men with CAG ≤19 had increased risk of prostate cancer

the odds of having a short CAG repeat (≤17) were substantially higher in patients with lymph node-positive prostate cancer than in those with lymph node-negative disease or in the general population

assessing the polymorphism at the AR level could be a potential tool towards individualized assessment and treatment of hypogonadism.

In elderly men, there was reduced testicular response to gonadotropins with suppressed and altered pulsatility of the hypothalamic pulse generator

a significant, independent and longitudinal effect of age on serum total testosterone level had been observed

A significant graded inverse association between serum testosterone level and insulin levels independent of age has also been reported in Caucasian men

Low testosterone is commonly associated with a high prevalence of MES

most studies showed that changes in serum testosterone level led to changes in body composition, insulin resistance and the presence of MES, the reverse might also be possible

MES predicted a 2.6-fold increased risk of development of low serum testosterone level independent of age, smoking and other potential confounders

Other prospective studies have shown that development of MES accelerated the age-related decline in serum testosterone level

In men with type 2 diabetes, changes in serum testosterone level over time correlated inversely with changes in insulin resistance

weight loss by either diet control or bariatric surgery led to a substantial increase in total testosterone, especially in morbidly obese men, and the rise in serum testosterone level was proportional to the amount of weight lost

To date, published clinical trials are small, of short duration and often used pharmacological, not physiological, doses of testosterone

In the population-based Osteoporotic Fractures in Men Study cohort from Sweden, men in the highest quartile of serum testosterone level had the lowest risk of cardiovascular events compared with men in the other three quartiles (hazard ratio [HR] 0.70

low serum total testosterone was associated with a significant fourfold higher risk of cardiovascular events when comparing men from the lowest testosterone tertile with those in the highest tertile

Shores et al. were the first to report that low serum testosterone level, including both serum total and free testosterone, was associated with increased mortality

low serum total testosterone predicted increased risk of cardiovascular mortality with a HR of 1.38

low serum total testosterone increased all-cause (HR 1.35, 95% CI 1.13–1.62, P < 0.001) and cardiovascular mortality (HR 1.25

European Association for the Study of Diabetes 2013 suggested there was an inverse relationship between serum testosterone level and acute myocardial infarction

Diabetic men in the highest quartile of serum total testosterone had a significantly reduced risk of acute MI when compared with those in the lower quartiles

serum total testosterone level in the middle two quartiles at baseline predicted reduced incidence of death compared with having the highest and lowest levels

The starting point for innate immunity activation is the recognition of conserved structures of bacteria, viruses, and fungal components through pattern-recognition receptors

TLRs are PRRs that recognize microbe-associated molecular patterns

TLRs are transmembrane proteins containing extracellular domains rich in leucine repeat sequences and a cytosolic domain homologous to the IL1 receptor intracellular domain

The major proinflammatory mediators produced by the TLR4 activation in response to endotoxin (LPS) are TNFα, IL1β and IL6, which are also elevated in obese and insulin-resistant patients

Obesity, high-fat diet, diabetes, and NAFLD are associated with higher gut permeability leading to metabolic endotoxemia.

Probiotics, prebiotics, and antibiotic treatment can reduce LPS absorption

LPS promotes hepatic insulin resistance, hypertriglyceridemia, hepatic triglyceride accumulation, and secretion of pro-inflammatory cytokines promoting the progression of fatty liver disease.

In the endothelium, LPS induces the expression of pro-inflammatory, chemotactic, and adhesion molecules, which promotes atherosclerosis development and progression.

In the adipose tissue, LPS induces adipogenesis, insulin resistance, macrophage infiltration, oxidative stress, and release of pro-inflammatory cytokines and chemokines.

the gut microbiota has been recently proposed to be an environmental factor involved in the control of body weight and energy homeostasis by modulating plasma LPS levels

dietary fats alone might not be sufficient to cause overweight and obesity, suggesting that a bacterially related factor might be responsible for high-fat diet-induced obesity.

This was accompanied in high-fat-fed mice by a change in gut microbiota composition, with reduction in Bifidobacterium and Eubacterium spp.

n humans, it was also shown that meals with high-fat and high-carbohydrate content (fast-food style western diet) were able to decrease bifidobacteria levels and increase intestinal permeability and LPS concentrations

it was demonstrated that, more than the fat amount, its composition was a critical modulator of ME (Laugerette et al. 2012). Very recently, Mani et al. (2013) demonstrated that LPS concentration was increased by a meal rich in saturated fatty acids (SFA), while decreased after a meal rich in n-3 polyunsaturated fatty acids (n-3 PUFA).

this effect seems to be due to the fact that some SFA (e.g., lauric and mystiric acids) are part of the lipid-A component of LPS and also to n-3 PUFA's role on reducing LPS potency when substituting SFA in lipid-A

these experimental results suggest a pivotal role of CD14-mediated TLR4 activation in the development of LPS-mediated nutritional changes.

This suggests a link between gut microbiota, western diet, and obesity and indicates that gut microbiota manipulation can beneficially affect the host's weight and adiposity.

endotoxemia was independently associated with energy intake but not fat intake in a multivariate analysis

in vitro that endotoxemia activates pro-inflammatory cytokine/chemokine production via NFκB and MAPK signaling in preadipocytes and decreased peroxisome proliferator-activated receptor γ activity and insulin responsiveness in adipocytes.

T2DM patients have mean values of LPS that are 76% higher than healthy controls

LPS-induced release of glucagon, GH and cortisol, which inhibit glucose uptake, both peripheral and hepatic

LPSs also seem to induce ROS-mediated apoptosis in pancreatic cells

Recent evidence has been linking ME with dyslipidemia, increased intrahepatic triglycerides, development, and progression of alcoholic and nonalcoholic fatty liver disease

The hepatocytes, rather than hepatic macrophages, are the cells responsible for its clearance, being ultimately excreted in bile

All the subclasses of plasma lipoproteins can bind and neutralize the toxic effects of LPS, both in vitro (Eichbaum et al. 1991) and in vivo (Harris et al. 1990), and this phenomenon seems to be dependent on the number of phospholipids in the lipoprotein surface (Levels et al. 2001). LDL seems to be involved in LPS clearance, but this antiatherogenic effect is outweighed by its proatherogenic features

LPS produces hypertriglyceridemia by several mechanisms, depending on LPS concentration. In animal models, low-dose LPS increases hepatic lipoprotein (such as VLDL) synthesis, whereas high-dose LPS decreases lipoprotein catabolism

When a dose of LPS similar to that observed in ME was infused in humans, a 2.5-fold increase in endothelial lipase was observed, with consequent reduction in total and HDL. This mechanism may explain low HDL levels in ‘ME’ and other inflammatory conditions such as obesity and metabolic syndrome

It is known that the high-fat diet and the ‘ME’ increase intrahepatic triglyceride accumulation, thus synergistically contributing to the development and progression of alcoholic and NAFLD, from the initial stages characterized by intrahepatic triglyceride accumulation up to chronic inflammation (nonalcoholic steatohepatitis), fibrosis, and cirrhosis

On the other hand, LPS activates Kupffer cells leading to an increased production of ROS and pro-inflammatory cytokines like TNFα

high-fat diet mice presented with ME, which positively and significantly correlated with plasminogen activator inhibitor (PAI-1), IL1, TNFα, STAMP2, NADPHox, MCP-1, and F4/80 (a specific marker of mature macrophages) mRNAs

prebiotic administration reduces intestinal permeability to LPS in obese mice and is associated with decreased systemic inflammation when compared with controls

Cani et al. also found that high-fat diet mice presented with not only ME but also higher levels of inflammatory markers, oxidative stress, and macrophage infiltration markers

This suggests that important links between gut microbiota, ME, inflammation, and oxidative stress are implicated in a high-fat diet situation

high-fat feeding is associated with adipose tissue macrophage infiltration (F4/80-positive cells) and increased levels of chemokine MCP-1, suggesting a strong link between ME, proinflammatory status, oxidative stress, and, lately, increased CV risk

LPS has been shown to promote atherosclerosis

markers of systemic inflammation such as circulating bacterial endotoxin were elevated in patients with chronic infections and were strong predictors of increased atherosclerotic risk

As a TLR4 ligand, LPS has been suggested to induce atherosclerosis development and progression, via a TLR4-mediated inflammatory state.

P serves as the precursor for the major steroid hormones (androgens, estrogens, corticosteroids) produced by the gonadal and adrenal cortical tissues.

5α-pregnane, 5β-pregnane, and 4-pregnene metabolites of P

These P-metabolizing enzymes included 5α-reductase, 5β-reductase, 3α-hydroxysteroid oxido-reductase (3α-HSO), 3β-HSO, 20α-HSO, 20β-HSO, 6α(β)-, 11β-, 17-, and 21-hydroxylase, and C17–20-lyase

Reduction of P to 5α-pregnanes is catalyzed by 5α-reductase and the direct 5α-reduced metabolite of P is 5α-pregnane-3,20-dione (5αP). The 5α-reductase reaction is irreversible

The two 4-pregnenes resulting from direct P conversion are 4-pregnen-3α-ol-20-one (3αHP) and 4-pregnen-20α-ol-3-one (20αHP), catalyzed by the actions of 3α-HSO and 20α-HSO respectively

the P-metabolizing enzyme activities identified in human breast tissues and cell lines were: 5α-reductase, 3α-HSO, 3β-HSO, 20α-HSO, and 6α-hydroxylase

In normal breast tissue, conversion to 4-pregnenes greatly exceeded the conversion to 5α-pregnanes, whereas in tumorous tissue, conversion to 5α-pregnanes greatly exceeded that to 4-pregnenes

The results indicated that P 5α-reductase activity is significantly higher, whereas P 3α-HSO and 20α-HSO activities are significantly lower in tumor than in normal tissues

he results showed that production of 5α-pregnanes was higher and that of 4-pregnenes was lower in tumorigenic (e.g. MCF-7) than in nontumorigenic (e.g. MCF-10A) cells (Fig. 3c⇑), while differences in ER/P status did not appear to play a role

The 5α-pregnane-to-4-pregnene ratios were 7- to 20-fold higher in the tumorigenic than in the nontumorigenic cell lines

altered direction in P metabolism, and hence in metabolite ratios, was due to significantly elevated 5α-reductase and depressed 3α- and 20α-HSO activities in breast tumor tissues and tumorigenic cells. It appeared, therefore, that changes in P-metabolizing enzyme activities might be related to the shift toward mammary cell tumorigenicity and neoplasia

In vivo, changes in enzyme activity can result from changes in levels of the enzyme due to changes in expression of the mRNA coding for the enzyme, or from changes in the milieu in which the enzyme operates (such as temperature and pH, and concentrations of cofactors, substrates, products, competitors, ions, phospholipids, and other molecules)

Overall, the enzyme activity and expression studies strongly suggest that 5α-reductase stimulation and 3α- and 20α-HSO suppression are associated with the transition from normalcy to cancer of the breast

The level of expression of 5α-reductase is up-regulated by estradiol and P in the uterus (Minjarez et al. 2001) and by 5α-dihydrotestosterone (DHT) in the prostate

3αHP inhibited whereas 5αP-stimulated proliferation

Stimulation in cell numbers was also observed when cells were treated with other 5α-pregnanes, such as 5α-pregnan-3α-ol-20-one, 5α-pregnan-20α-ol-3-one, and 5α-pregnane-3α,20α-diol, whereas other 4-pregnenes such as 20α-HP and 4-pregnene-3α,20α-diol resulted in suppression of cell proliferation

Stimulation of cell proliferation with 5αP and inhibition with 3αHP were also observed in all other breast cell lines examined, whether ER/P-negative (MCF-10A, MDA-MB-231) or ER/P-positive (T47D, ZR-75-1) and whether requiring estrogen for tumorigenicity (MCF-7, T47D) or not (MDA-MB-231), or whether they are nontumorigenic (

αHP resulted in significant increases in apoptosis and decreases in mitosis, leading to significant decreases in total cell numbers. In contrast, treatment with 5αP resulted in decreases in apoptosis and increases in mitosis.

The opposing actions of 5αP and 3αHP on both cell anchorage and proliferation strengthen the hypothesis that the direction of P metabolism in vivo toward higher 5α-pregnane and lower 4-pregnene concentrations could promote breast neoplasia and lead to malignancy.

he effects on proliferation and adhesion were not due to P, but due to the 5α-reduced metabolites

The studies showed that binding of 5αP or 3αHP occurs in the plasma membrane fractions, but not in the nuclear or cytosolic compartments

separate high-specificity, high-affinity, low- capacity receptors for 5αP and 3αHP that are distinct from each other and from the well-studied nuclear/cytosolic P, estrogen, and androgen and corticosteroid receptors

The studies thus provided the first demonstration of the existence of specific P metabolite receptors

the receptor results suggest that the putative tumorigenic actions of 5αP may be significantly augmented by the estradiol-induced increases in 5αP binding and decreases in 3αHP binding.

Estradiol and 5αP resulted in significant dose-dependent increases, whereas 3αHP and 20αHP each resulted in dose-dependent decreases in total ER

In combination, estradiol + 5αP or 3αHP + 20αHP resulted in additive increases or decreases respectively in ER numbers.

The data suggest that the action of 5αP on breast cancer cells involves modulation of the MAPK signaling pathway

current evidence does not appear to support the notion that increased 5α-reductase activity/ expression might significantly alter androgen influences on breast tumor growth.

both testosterone and DHT inhibit cell growth more or less to the same extent

Note that 5α-reductase reaction is not reversible

T may slow development of or progression of atherosclerosis by modulating effects on insulin resistance, inflammation, endothelial function, preclinical atherosclerosis or the vasculature.

these cross-sectional and longitudinal studies support a relationship between low circulating T with CIMT and higher E2 with its progression

lower levels of T are biomarkers for aortic vascular disease

circulating free T was negatively associated with the presence of AAA

luteinizing hormone (LH) was positively associated.

low levels of total or bioavailable T were associated with aortic atherosclerosis manifested as calcified deposits detected by radiography

Men with total or free T in the lowest quartile had increased adjusted ORs for PAD defined as ABI <0.90, as did men with free E2 in the highest quartile of values

The apparent association of SHBG with intermittent claudication reflects the correlation of total T with SHBG, while the contribution of E2 to risk of PAD remains unclear

men with total T in the lowest quartile of values (<11.7 nmol l−1 ) experienced an increased incidence of stroke or transient ischemic attack

lower total T with increased incidence of CVD events

cohort studies in mostly older men have supported the association of lower androgen levels with higher mortality

lower total or free T levels were associated with mortality in older men, but with discordant results for cause-specific mortality and for associations of E2

several large studies identifying lower endogenous levels of total or free T as independent predictors of all-cause or CVD-related deaths in middle-aged and older men

T exhibits anti-inflammatory effects, enhances flow-mediated brachial artery reactivity, and reduces arterial stiffness

Short-term T therapy had a beneficial effect on exercise-induced myocardial ischemia in middle-aged men with coronary artery disease or chronic stable angina, [95],[96],[97] and reduced angina frequency in older men with diabetes and coronary artery disease

T therapy resulted in an increase in treadmill test duration and time to ST segment depression

there are interventional studies supporting a protective effect of exogenous T against myocardial ischemia in men with coronary artery disease

employ conservative doses

Observational studies indicate that lower levels of endogenous T in older men are associated with the presence of carotid atherosclerosis, aortic and peripheral vascular disease, and incidence of CVD events and mortality

Interventional studies have shown beneficial effects of exogenous T on vascular function and on exercise-induced myocardial ischemia in men with coronary artery disease

Treatment with 3αHP subsequent to 5αP-induced tumor initiation resulted in suppression of further tumorigenesis and regression of existing tumors

Tumorigenesis of ER/PR-negative breast cells is significantly enhanced by 5αP and suppressed by 3αHP, the outcome depending on the relative concentrations of these two hormones in the microenvironment in the breast regions

The findings show that the production of 5αP greatly exceeds that of 3αHP in ER/PR-negative tumors and that treatment with 3αHP can effectively block tumorigenesis and cause existing tumors to regress

hypothesis that a high 3αHP-to-5αP concentration ratio in the microenvironment may foster normalcy in noncancerous breast regions.

a large proportion (about 30% to 60%) of breast tumors are ER and/or PR negative

about 90% of normal proliferating breast epithelial cells are receptor negative

Our previous in vitro studies had shown that breast tissues and cell lines readily convert progesterone to 5α-pregnanes, such as 5αP, and delta-4-pregnenes, such as 3αHP (Figure ​(Figure1),1), and that tumorous breast tissues [15] and tumorigenic breast cell lines [16] produce higher levels of 5αP and lower levels of 3αHP than do normal breast tissues and nontumorigenic cell lines

The progesterone metabolism studies suggested that increases in 5αP and decreases in 3αHP production accompany the shift toward breast cell neoplasia and tumorigenicity

In vitro studies on five different human breast cell lines showed that cell proliferation and detachment are significantly increased by 5αP and decreased by 3αHP

the prevailing theory of hormonal regulation of breast cancer, as well as hormone-based therapies, revolves around estrogen and/or progesterone and ER/PR-positive breast cells and tumors.

Not only do these "receptor-negative" breast cancers fail to benefit from current hormonal therapies, but they also generally exhibit more-aggressive biologic behaviors and poorer prognosis than the receptor-positive ones

The results of the studies reported here show for the first time that the progesterone metabolites, 5αP and 3αHP, act as hormones that regulate ER/PR-negative breast tumor formation, growth, and regression

The onset of the ER/PR-negative human breast cell tumors in mice was considerably accelerated, and the growth significantly stimulated, by just one or two applications of 5αP

In contrast, 3αHP retarded onset of tumor formation, suppressed tumor growth, and inhibited or regressed existing 5αP-induced tumors

When both hormones were administered simultaneously, the effects of one were abrogated by the effects of the other.

The 5αPR and 3αHPR (which are associated with the plasma membranes of both ER/PR-positive [19] and ER/PR-negative [29] cells) are distinct from each other and from known ER, PR, androgen, and corticosteroid receptors, and lack affinity for other steroids, such as progesterone, estrogen, androgens, corticosteroids, and other progesterone metabolites

Levels of 5αPR are upregulated by 5αP itself and estradiol, and downregulated by 3αHP in both ER/PR-positive and -negative cells

ndications are that 5αP acts via the surface receptor-linked mitogen-activated protein kinase (MAPK; Erk1/2) pathway; 5αP significantly stimulates activation of Erk1/2 [30], increases the Bcl-2/Bax expression ratio [18] and actin depolymerization [31], and decreases expression of actin and adhesion plaque-associated vinculin [31], resulting in decreased apoptosis and increased mitosis and cell detachment

3αHP appears to suppress protein kinase C (PKC), phospholipase C (PLC), Ca2+ mobilization (unpublished observations), and the Bcl-2/Bax expression ratio [18], and increases expression of the cell-cycle inhibitor p21 [18], resulting in increased apoptosis and decreased proliferation and detachment of breast cell lines.

serum from mice with tumors had significantly more 5αP than 3αHP

the tumors, which on average had about threefold higher concentrations of 5αP than the respective sera, and >10-fold higher 5αP than 3αHP levels

Previous in vitro metabolism studies showed that human breast tumor tissues convert significantly more progesterone to 5α-pregnanes like 5αP and less to 4-pregnenes like 3αHP than do paired normal (nontumorous) tissues

Similar differences in progesterone metabolism and enzyme gene expressions were observed between tumorigenic and nontumorigenic breast cell lines

breast carcinomas are able to synthesize progesterone

The current findings, along with the previous in vitro studies, suggest that the relative concentrations of 5αP and 3αHP in the breast microenvironment constitute important autocrine/paracrine determinants not only for tumorigenesis but also for potential regression of tumors and the maintenance of normalcy of ER/PR-negative breast cells/tissues.

Evidence presented here shows that a high concentration of 5αP, relative to 3αHP in the microenvironment, promotes initiation and growth of tumors, whereas a higher concentration of 3αHP, relative to 5αP, suppresses tumorigenesis and promotes normalcy

5α-reductase and 5αPR levels are upregulated by 5αP

in the 3αHP-treated mice, the elevated 3αHP levels, relative to 5αP, in the microenvironment could have opposed progression to xenograft neoplasia by its inherent anticancer actions and the suppression of 5αP synthesis and 5αPR expression

the opposing actions of the progesterone metabolites also appear to exert some control over the estrogen-regulated effects on breast cancer by their ability to modulate ER numbers in ER-positive cells

because both ER/PR-negative and ER/PR-positive, as well as normal and tumorigenic human breast cell lines, have been shown to respond to 5αP and 3αHP in vitro, it is suggested that these endogenously produced progesterone metabolites may also play regulatory hormonal roles in ER/PR-positive breast cancers, as well as in the maintenance of normalcy in nontumorous breast tissues.

The in vivo data provide further evidence that progesterone metabolites, such as 5αP and 3αHP, deserve to be considered as active hormones in their own right, rather than inactive waste products