Group items tagged

progesterone

prolactin

In summary, in vivo animal experiments have shown an inhibitory role of estrogen on peripheral NK cell lytic activity, which is partly due to suppression of NK cell output by the bone marrow and partly due to suppression of individual NK cell cytotoxicity. However, in vitro studies so far have failed to show conclusively a direct effect of estrogen on NK cells.

At the progesterone concentrations believed to be present in the uterus [up to 10−5 m at the maternal-fetal interface (35)], studies consistently show inhibition of lymphocyte proliferation (33) and inhibition of NK cytolytic activity in vitro

The exact role of prolactin in NK cell regulation is unknown.

The overall effects of estrogen on NK cells are likely multifactorial, therefore, and depend on the type of cell affected as well as the kind of ER expressed by that cell.

It is known that progesterone can directly affect T cell differentiation in vitro, suppressing development of the Th1 pathway and enhancing differentiation along the Th2 pathway (44)

Th1 cells predominantly produce interferon-γ (IFN-γ), IL-2, and TNF-β and are involved in cell-mediated immunity. Th2 cells produce IL-4, IL-5, IL-6, IL-10, and IL-13 and stimulate humoral immunity

Furthermore, in response to progesterone, γδ T cells produce progesterone-induced blocking factor (PIBF) (54

A defining characteristic of NK cells is their ability to lyse target cells without prior sensitization and without restriction by HLA antigens.

NK cell function is mainly regulated by IL-2 and IFN-γ

IL-2 causes both NK cell proliferation and enhanced cytotoxicity. IFN-γ augments NK cytolytic activity, but does not cause NK proliferation. The two cytokines act synergistically to augment NK cytotoxicity (6).

The largest leukocyte population in the endometrium consists of NK cells named large granulated lymphocytes

there is a significant increase in the number of uNK cells throughout the secretory phase, which peaks in early pregnancy when uNK cells comprise about 75% of uterine leukocytes (62)

Second, uNK cell phenotype changes during the normal menstrual cycle and early pregnancy (68)

general proinflammatory effect of estrogen, causing an influx of macrophages and neutrophils, which is antagonized by progesterone through its receptor (70, 71).

The mechanism of such a progesterone-induced local immunosuppression is unclear.

progesterone plays an important role in proliferation and differentiation of uNK cells (32).

Through promotion of a uterine Th2 environment, progesterone could indirectly affect uNK cell function

The mechanism of this increase in uNK cell numbers has been addressed in both human and mouse models, and is likely the result of: 1) recruitment of peripheral NK cells to the uterus, and 2) proliferation of existing uNK cells

prolactin system plays an important role in implantation and the maintenance of pregnancy

the exact pathways of hormonal regulation of NK cells remain to be delineated.

The exact function of uNK cells has not yet been unequivocally determined

uNK cells express a different cytokine profile, compared with resting peripheral NK cells. mRNAs for granulocyte CSF, M-CSF, GM-CSF, TNF-α, IFN-γ, TGF-β, and leukemia inhibitory factor (LIF) have been found in decidual CD56+ cells

Their increased numbers in early pregnancy, their hormonal dependence, and their close proximity to the infiltrating trophoblast all suggest that they play an important role in the regulation of the maternal immune response to the fetal allograft and the control of trophoblast growth and invasion during human pregnancy

role of uNK cell-derived cytokines on trophoblast growth and differentiation (114, 115, 116, 117).

Th1 immunity to trophoblast is associated with RPL, whereas Th2 immunity is associated with a successful pregnancy

RPL is associated with Th1 immunity, for which NK cells are partly responsible.

malnutrition progressing to cachexia is another common manifestation of cirrhosis

Malnutrition can be mitigated with BCAA supplementation

Studies show that administration of amino acid formulas enriched with BCAAs can reduce protein loss, support protein synthesis, and improve nutritional status of patients with chronic liver disease

Leucine has been shown to be the most effective of the BCAAs because it acts via multiple pathways to stimulate protein synthesis

BCAAs metabolites inhibit proteolysis

Patients with cirrhosis have both insulin deficiency and insulin resistance

BCAAs (particularly leucine) help to reverse the catabolic, hyperglucagonemic state of cirrhosis both by stimulating insulin release from the pancreatic β cells and by decreasing insulin resistance allowing for better glucose utilization

Coadministration of BCAAs and glucose has been found to be particularly useful

BCAA supplementation improves protein-energy malnutrition by improving utilization of glucose, thereby diminishing the drive for proteolysis, inhibiting protein breakdown, and stimulating protein synthesis

Cirrhotic patients have impaired immune defense, characterized by defective phagocytic activity and impaired intracellular killing activity

another effect of BCAA supplementation is improvement of phagocytic function of neutrophils and possibly improvement in natural killer T (NKT) cell lymphocyte activity

BCAA supplementation may reduce the risk of infection in patients with advanced cirrhosis not only through improvement in protein-energy malnutrition but also by directly improving the function of the immune cells themselves

BCAA administration has also been shown to have a positive effect on liver regeneration

A proposed mechanism for improved liver regeneration is the stimulatory effect of BCAAs (particularly leucine) on the secretion of hepatocyte growth factor by hepatic stellate cells

BCAAs activate rapamycin signaling pathways which promotes albumin synthesis in the liver as well as protein and glycogen synthesis in muscle tissue

Chemical improvement with BCAA treatment is demonstrated by recovery of serum albumin and lowering of serum bilirubin levels

long-term oral BCAA supplementation was useful in staving off malnutrition and improving survival by preventing end-stage fatal complications of cirrhosis such as hepatic failure and gastrointestinal bleeding

The incidence of death by any cause, development of liver cancer, rupture of esophageal varices, or progression to hepatic failure was decreased in the group that received BCAA supplementation

Patients receiving BCAA supplementation also have a lower average hospital admission rate, better nutritional status, and better liver function tests

patients taking BCAA supplementation report improved quality of life

BCAAs have been shown to mitigate hepatic encephalopathy, cachexia, and infection rates, complications associated with the progression of hepatic cirrhosis

BCAAs make up 20-25% of the protein content of most foods

Highest levels are found in casein whey protein of dairy products and vegetables, such as corn and mushrooms. Other sources include egg albumin, beans, peanuts and brown rice bran

In addition to BCAAs from diet, oral supplements of BCAAs can be used

Oral supplementation tends to provide a better hepatic supply of BCAAs for patients able to tolerate PO nutrition as compared with IV supplementation, especially when treating symptoms of hepatic encephalopathy

Coadministration of BCAAs with carnitine and zinc has also been shown to increase ammonia metabolism further reducing the encephalopathic symptoms

Cirrhotic patients benefit from eating frequent, small meals that prevent long fasts which place the patient in a catabolic state

the best time for BCAA supplementation is at bedtime to improve the catabolic state during starvation in early morning fasting

A late night nutritional snack reduces symptoms of weakness and fatigability, lowers postprandial hyperglycemia, increases skeletal muscle mass,[25] improves nitrogen balance, and increases serum albumin levels.[26] Nocturnal BCAAs even improve serum albumin in cirrhotic patients who show no improvement with daytime BCAAs

Protein-energy malnutrition (PEM), with low serum albumin and low muscle mass, occurs in 65-90% of cases of advanced cirrhosis

hyperglucagonemia results in a catabolic state eventually producing anorexia and cachexia

BCAAs are further depleted from the circulation due to increased uptake by skeletal muscles that use the BCAAs in the synthesis of glutamine, which is produced in order to clear the ammonia that is not cleared by the failing liver

patients with chronic liver disease, particularly cirrhosis, routinely have decreased BCAAs and increased aromatic amino acids (AAAs) in their circulation

Maintaining a higher serum albumin in patients with cirrhosis is associated with decreased mortality and improved quality of life

the serum BCAA concentration is strongly correlated with the serum albumin level

basal (diurnal) concentrations of cortisol do not exert an anti-inflammatory effect on several pro-and anti-inflammatory mediators of the human immune inflammatory response

withdrawal of cortisol activity in vivo did not lead to increased inflammatory responsiveness of immune effector cells

maximal suppression of inflammation was achieved by a stress-associated, but still physiologic, cortisol concentration. There was no greater anti-inflammatory effect at higher cortisol concentrations (Yeager et al. 2005) although IL-10 concentrations continued to increase with increasing cortisol concentrations as we and others have shown

acutely, physiological cortisol concentrations are anti-inflammatory and, as proposed, act to limit over expression of an inflammatory response that could lead to tissue damage

Acutely, cortisol has anti-inflammatory effects following a systemic inflammatory stimulus (Figure 4). However, a cortisol concentration that acts acutely to suppress systemic inflammation also has a delayed effect of augmenting the inflammatory response to subsequent, delayed stimulu

1) GCs can exert pro-inflammatory effects on key inflammatory processes and, 2) GC regulation of inflammation can vary from anti- to a pro-inflammatory in a time-dependent manner

The immediate in vivo effect of both stress-induced and pharmacological GC concentrations is to suppress concurrent inflammation and protect the organism from an excessive or prolonged inflammatory response

GCs alone, in the absence of an inflammatory stimulus, up-regulate monocyte mRNA and/or receptors for several molecules that participate in pro-inflammatory signaling, as noted above and in the studies presented here.

In humans, as shown here, if in vivo GC concentrations are elevated concurrent with an inflammatory stimulus, anti-inflammatory effects are observed

In sharp contrast, with a time delay of 12 or more hours between an increased GC concentration and the onset of an inflammatory stimulus, enhancing effects on inflammation are observed. These effects have been shown to persist in humans for up to 6 days

GC-induced enhancement of inflammatory responses is maximal at an intermediate concentration, in our studies at a concentration that approximates that observed in vivo following a major systemic inflammatory stimulus

In addition to enhanced responses to LPS, recently identified pro-inflammatory effects of GCs also show enhanced localization of effector cells at inflammatory sites

we hypothesize that pre-exposure to stress-associated cortisol concentrations “prime” effector cells of the monocyte/macrophage lineage for an augmented pro-inflammatory response by; a) inducing preparative changes in key regulators of LPS signal transduction, and b) enhancing localization of inflammatory effector cells at potential sites of injury

related to intracellular hydrogen peroxide generation

only be obtained by intravenous administration of AA

Preferentially kills neoplastic cells

Is virtually non-toxic at any dosage

Does not suppress the immune system, unlike most chemotherapy agents

Increases animal and human resistance to infectious agents by enhancing lymphocyte blastogenesis, enhancing cellular immunity, strengthening the extracellular matrix, and enhancing bactericidal activity of neutrophils and modulation of complement protein

Strengthens the structural integrity of the extracellular matrix which is responsible for stromal resistance to malignant invasiveness

1969, researchers at the NCI reported AA was highly toxic to Ehrlich ascites cells in vitro

In 1977, Bram et al reported preferential AA toxicity for several malignant melanoma cell lines, including four human-derived lines

Noto et al reported that AA plus vitamin K3 had growth inhibiting action against three human tumor cell lines at non-toxic levels

Metabolites of AA have also shown antitumor activity in vitro

The AA begins to reduce cell proliferation in the tumor cell line at the lowest concentration, 1.76 mg/dl, and is completely cytotoxic to the cells at 7.04 mg/dl

the normal cells grew at an enhanced rate at the low dosages (1.76 and 3.52 mg/dl)

preferential toxicity of AA for tumor cells. >95% toxicity to human endometrial adenocarcinoma and pancreatic tumor cells (ATCC AN3-CA and MIA PaCa-2) occurred at 20 and 30 mg/dl, respectively.

No toxicity or inhibition was demonstrated in the normal, human skin fibroblasts (ATCC CCD 25SK) even at the highest concentration of 50 mg/dl.

the use of very high-dose intravenous AA for the treatment of cancer was proposed as early as 1971

Cameron and Pauling have published extensive suggestive evidence for prolonged life in terminal cancer patients orally supplemented (with and without initial intravenous AA therapy) with 10 g/day of AA

AA, plasma levels during infusion were not monitored,

the long-term, oral dosage used in those experiments (10 g/day), while substantial and capable of producing immunostimulatory and extracellular matrix modulation effects, was not high enough to achieve plasma concentrations that are generally cytotoxic to tumor cells in culture

This low cytotoxic level of AA is exceedingly rare

5 — 40 mg/dl of AA is required in vitro to kill 100% of tumor cells within 3 days. The 100% kill levels of 30 mg/dl for the endometrial carcinoma cells and 40 mg/dl for the pancreatic carcinoma cells in Figure 2 are typical

normal range (95% range) of 0.39-1.13 mg/dl

1 h after beginning his first 8-h infusion of 115 g AA (Merit Pharmaceuticals, Los Angeles, CA), the plasma AA was 3.7 mg/dl and at 5 h was 19 mg/dl. During his fourth 8-h infusion, 8 days later, the 1 h plasma level was 158 mg/dl and 5 h was 185 mg/dl

plasma levels of over 100 mg/dl have been maintained in 3 patients for more than 5 h using continuous intravenous infusion

In rare instances of patients with widely disseminated and rapidly proliferating tumors, intravenous AA administration (10 — 45 g/day) precipitated widespread tumor hemorrhage and necrosis, resulting in death

Although the outcomes were disastrous in these cases, they are similar to the description of tumor-necrosis-factor-induced hemorrhage and necrosis in mice (52) and seem to demonstrate the ability of AA to kill tumor cells in vivo.

toxic effects of AA on one normal cell line were observed at 58.36 mg/dl and the lack of side effects in patients maintaining >100 mg/dl plasma levels

Although it is very rare, tumor necrosis, hemorrhage, and subsequent death should be the highest priority concern for the safety of intravenous AA for cancer patients.

Klenner, who reported no ill effects of dosages as high as 150 g intravenously over a 24-h period

Cathcart (55) who describes no ill effects with doses of up to 200 g/d in patients with various pathological conditions

following circumstances: renal insufficiency, chronic hemodialysis patients, unusual forms of iron overload, and oxalate stone formers

Screening for red cell glucose-6-phosphate dehydrogenase deficiency, which can give rise to hemolysis of red blood cells under oxidative stress (57), should also be performed

any cancer therapy should be started at a low dosage to ensure that tumor hemorrhage does not occur.

patient is orally supplementing between infusions

a scorbutic rebound effect can be avoided with oral supplementation. Because of the possibility of a rebound effect, measurement of plasma levels during the periods between infusions should be performed to ensure that no such effect takes place

Every effort should be made to monitor plasma AA levels when a patient discontinues intravenous AA therapy.

Our data show that ascorbic acid selectively killed cancer but not normal cells, using concentrations that could only be achieved by i.v. administration

Ascorbate-mediated cell death was due to protein-dependent extracellular H2O2 generation, via ascorbate radical formation from ascorbate as the electron donor. Like glucose, when ascorbate is infused i.v., the resulting pharmacologic concentrations should distribute rapidly in the extracellular water space (42). We showed that such pharmacologic ascorbate concentrations in media, as a surrogate for extracellular fluid, generated ascorbate radical and H2O2. In contrast, the same pharmacologic ascorbate concentrations in whole blood generated little detectable ascorbate radical and no detectable H2O2. These findings can be accounted for by efficient and redundant H2O2 catabolic pathways in whole blood (e.g., catalase and glutathione peroxidase) relative to those in media or extracellular fluid

ascorbic acid administered i.v. in pharmacologic concentrations may serve as a pro-drug for H2O2 delivery to the extracellular milieu

H2O2 generated in blood is normally removed by catalase and glutathione peroxidase within red blood cells, with internal glutathione providing reducing equivalents

The electron source for glutathione is NADPH from the pentose shunt, via glucose-6-phosphate dehydrogenase. If activity of this enzyme is diminished, the predicted outcome is impaired H2O2 removal causing intravascular hemolysis, the observed clinical finding.

Only recently has it been understood that the discordant clinical findings can be explained by previously unrecognized fundamental pharmacokinetics properties of ascorbate

Intracellular transport of ascorbate is tightly controlled in relation to extracellular concentration

Intravenous ascorbate infusion is expected to drastically change extracellular but not intracellular concentrations

For i.v. ascorbate to be clinically useful in killing cancer cells, pharmacologic but not physiologic extracellular concentrations should be effective, independent of intracellular ascorbate concentrations.

It is unknown why ascorbate, via H2O2, killed some cancer cells but not normal cells.

There was no correlation with ascorbate-induced cell death and glutathione, catalase activity, or glutathione peroxidase activity.

H2O2, as the product of pharmacologic ascorbate concentrations, has potential therapeutic uses in addition to cancer treatment, especially in infections

Neutrophils generate H2O2 from superoxide,

i.v. ascorbate is effective in some viral infections

H2O2 is toxic to hepatitis C

Use of ascorbate as an H2O2-delivery system against sensitive pathogens, viral or bacterial, has substantial clinical implications that deserve rapid exploration.

Recent pharmacokinetics studies in men and women show that 10 g of ascorbate given i.v. is expected to produce plasma concentrations of nearly 6 mM, which are >25-fold higher than those concentrations from the same oral dose

As much as a 70-fold difference in plasma concentrations is expected between oral and i.v. administration,

Complementary and alternative medicine practitioners worldwide currently use ascorbate i.v. in some patients, in part because there is no apparent harm

Human Burkitt's lymphoma cells

We first investigated whether ascorbate in pharmacologic concentrations selectively affected the survival of cancer cells by studying nine cancer cell lines

Clinical pharmacokinetics analyses show that pharmacologic concentrations of plasma ascorbate, from 0.3 to 15 mM, are achievable only from i.v. administration

plasma ascorbate concentrations from maximum possible oral doses cannot exceed 0.22 mM because of limited intestinal absorption

For five of the nine cancer cell lines, ascorbate concentrations causing a 50% decrease in cell survival (EC50 values) were less than 5 mM, a concentration easily achievable from i.v. infusion

All tested normal cells were insensitive to 20 mM ascorbate.

Lymphoma cells were selected because of their sensitivity to ascorbate

As ascorbate concentration increased, the pattern of death changed from apoptosis to pyknosis/necrosis, a pattern suggestive of H2O2-mediated cell death

Apoptosis occurred by 6 h after exposure, and cell death by pyknosis was ≈90% at 14 h after exposure

In contrast to lymphoma cells, there was little or no killing of normal lymphocytes and monocytes by ascorbate

Ascorbate is transported into cells as such by sodium-dependent transporters, whereas dehydroascorbic acid is transported into cells by glucose transporters and then immediately reduced internally to ascorbate

Whether or not intracellular ascorbate was preloaded, extracellular ascorbate induced the same amount and type of death.

extracellular ascorbate in pharmacologic concentrations mediates death of lymphoma cells by apoptosis and pyknosis/necrosis, independently of intracellular ascorbate.

H2O2 as the effector species mediating pharmacologic ascorbate-induced cell death

Superoxide dismutase was not protective

Because these data implicated H2O2 in cell killing, we added H2O2 to lymphoma cells and studied death patterns using nuclear staining (19, 28). The death patterns found with exogenous H2O2 exposure were similar to those found with ascorbate

For both ascorbate and H2O2, death changed from apoptosis to pyknosis/necrosis as concentrations increased

Sensitivity to direct exposure to H2O2 was greater in lymphoma cells compared with normal lymphocytes and normal monocytes

There was no association between the EC50 for ascorbate-mediated cell death and intracellular glutathione concentrations, catalase activity, or glutathione peroxidase activity

H2O2 generation was dependent on time, ascorbate concentration, and the presence of trace amounts of serum in media

ascorbate radical is a surrogate marker for H2O2 formation.

whatever H2O2 is generated should be removed by glutathione peroxidase and catalase within red blood cells, because H2O2 is membrane permeable

The data are consistent with the hypothesis that ascorbate in pharmacologic concentrations is a pro-drug for H2O2 generation in the extracellular milieu but not in blood.

The occurrence of one predicted complication, oxalate kidney stones, is controversial

In patients with glucose-6-phosphate dehydrogenase deficiency, i.v. ascorbate is contraindicated because it causes intravascular hemolysis

ascorbate at pharmacologic concentrations in blood is a pro-drug for H2O2 delivery to tissues.

ascorbate, an electron-donor in such reactions, ironically initiates pro-oxidant chemistry and H2O2 formation

data here showed that ascorbate initiated H2O2 formation extracellularly, but H2O2 targets could be either intracellular or extracellular, because H2O2 is membrane permeant

More than 100 patients have been described, presumably without glucose-6-phosphate dehydrogenase deficiency, who received 10 g or more of i.v. ascorbate with no reported adverse effects other than tumor lysis

it does appear to inhibit rejoining of RT-induced DNA breaks more than is commonly observed after RT alone

HT damages cells and enhances RT and CT sensitivity as a function of both temperature and duration of treatment

as temperature or duration increase, the rate of cell killing also increases

At temperatures above 42 °C, tumor vasculature is damaged, resulting in decreased blood flow

Cancer cells are particularly vulnerable to heating; in vivo studies have shown that temperatures in the range of 40–44 °C cause more selective damage to tumor cells

cancerous blood vessels are chaotic, leaky, and inefficient

selective cytotoxic effect on tumor cells include inhibition of key cancer cell-signaling pathways such as AKT, inducing apoptosis, suppression of cancer stem cell proliferation, and others

increase in immunological attacks against tumors after HT, which were believed to be achieved through activation of HSPs and subsequent modulation of the innate and adaptive immune responses against tumor cells

HT does lead to activation of the immune system and HSP-induced cell death through modification of the tumor cell surface

These HSPs and tumor antigens are taken up by dendritic cells and macrophages and go on to induce specific anti-tumor immunity

In vivo studies demonstrate HT-enhancement of NK cell activity, and HT has been shown to increase neutrophilic granulocytes with anti-tumor activity

it has become increasingly clear that HT results in immune stimulation, through both direct heat-mediated cell killing as well as innate and adaptive immune system modulation

The term hyperthermia is used in this review to refer to heating within the clinically accepted range of 40–45 °C

temperatures above 42.5–43 °C the exposure time can be halved with each 1 °C increase while maintaining equivalent cell killing

gradual heating at 43 °C for 1 h worked through an apoptotic pathway