Testosterone has beneficial
effects on several cardiovascular risk factors, which include cholesterol, endothelial dysfunction and inflammation
In clinical studies, acute and chronic testosterone administration increases coronary artery diameter and flow, improves
cardiac ischaemia and symptoms in men with chronic stable angina and reduces peripheral vascular resistance in chronic heart
failure.
testosterone is an L-calcium channel blocker and induces potassium
channel activation in vascular smooth muscle cells
Animal studies have consistently demonstrated that testosterone is atheroprotective,
whereas testosterone deficiency promotes the early stages of atherogenesis
there is no compelling evidence that testosterone replacement to levels within the normal healthy range contributes
adversely to the pathogenesis of CVD (Carson & Rosano 2011) or prostate cancer (Morgentaler & Schulman 2009)
bidirectional effect between decreased testosterone
concentrations and disease pathology exists as concomitant cardiovascular risk factors (including inflammation, obesity and
insulin resistance) are known to reduce testosterone levels and that testosterone confers beneficial effects on these cardiovascular
risk factors
Achieving a normal physiological testosterone concentration through the administration
of testosterone replacement therapy (TRT) has been shown to improve risk factors for atherosclerosis including reducing central
adiposity and insulin resistance and improving lipid profiles (in particular, lowering cholesterol), clotting and inflammatory
profiles and vascular function
It is well known that impaired erectile function and CVD are closely
related in that ED can be the first clinical manifestation of atherosclerosis often preceding a cardiovascular event by 3–5
years
no decrease in the response (i.e. no tachyphylaxis) of testosterone and that patient benefit persists in the long term.
free testosterone
levels within the physiological range, has been shown to result in a marked increase in both flow- and nitroglycerin-mediated
brachial artery vasodilation in men with CAD
Clinical studies, however, have revealed either small reductions of 2–3 mm in diastolic pressure or no significant effects
when testosterone is replaced within normal physiological limits in humans
Endothelium-independent mechanisms of testosterone
are considered to occur primarily via the inhibition of voltage-operated Ca2+ channels (VOCCs) and/or activation of K+ channels (KCs) on smooth muscle cells (SMCs)
Testosterone shares the same molecular binding site as nifedipine
Testosterone increases the expression of endothelial nitric oxide synthase (eNOS)
and enhances nitric oxide (NO) production
Testosterone also inhibited
the Ca2+ influx response to PGF2α
one of the major actions of testosterone is on NO and its signalling pathways
In addition to direct effects on NOS expression, testosterone may also affect phosphodiesterase type 5 (PDE5 (PDE5A)) gene expression, an enzyme controlling the degradation of cGMP, which acts as a vasodilatory second messenger
the significance of the action of testosterone on VSMC apoptosis and proliferation in atherosclerosis is difficult
to delineate and may be dependent upon the stage of plaque development
Several human studies have shown that carotid IMT (CIMT) and aortic calcification negatively correlate
with serum testosterone
t long-term testosterone treatment reduced CIMT in men with low testosterone levels
and angina
neither intracellular nor membrane-associated
ARs are required for the rapid vasodilator effect
acute responses appear to be AR independent, long-term AR-mediated effects on the vasculature have also been described,
primarily in the context of vascular tone regulation via the modulation of gene transcription
Testosterone and DHT increased the expression of eNOS in HUVECs
oestrogens have been shown to activate eNOS and stimulate NO production in an ERα-dependent manner
Several studies, however, have demonstrated that the vasodilatory actions of testosterone are not reduced by aromatase
inhibition
non-aromatisable DHT elicited similar vasodilation to testosterone treatment in arterial smooth muscle
increased endothelial NOS (eNOS) expression and phosphorylation were observed in testosterone- and DHT-treated
human umbilical vein endothelial cells
Androgen deprivation leads to a reduction in neuronal NOS expression associated with a decrease of intracavernosal pressure
in penile arteries during erection, an effect that is promptly reversed by androgen replacement therapy
Observational evidence suggests that several pro-inflammatory cytokines (including interleukin 1β (IL1β), IL6, tumour necrosis
factor α (TNFα), and highly sensitive CRP) and serum testosterone levels are inversely associated in patients with CAD, T2DM
and/or hypogonadism
patients with the
highest IL1β concentrations had lower endogenous testosterone levels
TRT has been reported to significantly
reduce TNFα and elevate the circulating anti-inflammatory IL10 in hypogonadal men with CVD
testosterone treatment to normalise levels in hypogonadal men with the MetS
resulted in a significant reduction in the circulating CRP, IL1β and TNFα, with a trend towards lower IL6 compared with placebo
parenteral testosterone undecanoate, CRP decreased significantly in hypogonadal elderly
men
Higher levels of serum adiponectin have been shown to lower cardiovascular risk
Research suggests that the expression of VCAM-1, as induced by pro-inflammatory cytokines such as TNFα or interferon γ (IFNγ
(IFNG)) in endothelial cells, can be attenuated by treatment with testosterone
Testosterone also inhibits the production of pro-inflammatory cytokines such as IL6, IL1β and TNFα in a range of cell types
including human endothelial cells
decreased inflammatory response to TNFα and lipopolysaccharide (LPS) in
human endothelial cells when treated with DHT
The key to unravelling the link between testosterone
and its role in atherosclerosis may lay in the understanding of testosterone signalling and the cross-talk between receptors
and intracellular events that result in pro- and/or anti-inflammatory actions in athero-sensitive cells.
testosterone
functions through the AR to modulate adhesion molecule expression
pre-treatment with DHT reduced the cytokine-stimulated inflammatory response
DHT inhibited NFκB activation
DHT could inhibit an LPS-induced upregulation of MCP1
Both NFκB and
AR act at the transcriptional level and have been experimentally found to be antagonistic to each other
As the AR and NFκB are mutual antagonists, their interaction and influence on functions can be bidirectional, with inflammatory
agents that activate NFκB interfering with normal androgen signalling as well as the AR interrupting NFκB inflammatory transcription
prolonged exposure of vascular cells to the inflammatory activation of NFκB associated with atherosclerosis
may reduce or alter any potentially protective effects of testosterone
DHT and IFNγ also modulate each other's signalling through interaction at the transcriptional
level, suggesting that androgens down-regulate IFN-induced genes
(Simoncini et al. 2000a,b). Norata et al. (2010) suggest that part of the testosterone-mediated atheroprotective effects could depend on ER activation mediated by the testosterone/DHT
3β-derivative, 3β-Adiol
TNFα-induced induction of ICAM-1, VCAM-1 and E-selectin as well as MCP1 and IL6 was significantly
reduced by a pre-incubation with 3β-Adiol in HUVECs
3β-Adiol also reduced LPS-induced gene expression
of IL6, TNFα, cyclooxygenase 2 (COX2 (PTGS2)), CD40, CX3CR1, plasminogen activator inhibitor-1, MMP9, resistin, pentraxin-3 and MCP1 in the monocytic cell line U937 (Norata et al. 2010)
This study suggests that testosterone metabolites, other than those generated through aromatisation, could exert anti-inflammatory
effects that are mediated by ER activation.
The authors suggest that DHT differentially
effects COX2 levels under physiological and pathophysiological conditions in human coronary artery smooth muscle cells and
via AR-dependent and -independent mechanisms influenced by the physiological state of the cell
There are, however, a number of systematic meta-analyses of clinical trials of TRT that have not demonstrated
an increased risk of adverse cardiovascular events or mortality
The TOM trial, which was designed to investigate the effect of TRT on frailty in elderly men, was terminated prematurely
as a result of an increased incidence of cardiovascular-related events after 6 months in the treatment arm
trials of TRT in men with either chronic stable angina or chronic cardiac failure have also found no increase
in either cardiovascular events or mortality in studies up to 12 months
Evidence may therefore suggest that low testosterone levels and testosterone levels above the normal range have an adverse
effect on CVD, whereas testosterone levels titrated to within the mid- to upper-normal range have at least a neutral effect
or, taking into account the knowledge of the beneficial effects of testosterone on a series of cardiovascular risk factors,
there may possibly be a cardioprotective action
The effect of testosterone on human vascular function is a complex issue and may be dependent upon the underlying androgen
and/or disease status.
the majority of studies suggest that testosterone may display both acute and
chronic vasodilatory effects upon various vascular beds at both physiological and supraphysiological concentrations and via
endothelium-dependent and -independent mechanisms
Higher vitamin D levels associated with lower cardio biomarkers: insulin, insulin resistance, triglycerides, TC, LDL and TC:HDL. Not found to be associated: glucose, apoliporotein A1 and B, CRP, fibrinogen, and homocysteine.
This article's conclusion fits the definition of insane.
This article found that the flu vaccine in pregnant women found significant increased CRP, TNF-alpha, and IL-6 inflammatory biomarkers. It is well recognized the impact of inflammation on health and in this case the developing baby. For example, preeclampsia and preterm birth are inflammatory conditions. Yet, ACOG has made recommmendations for all pregnant women to get the flu vaccine?!?!
Here is their conclusion: "However, further research is needed to confirm that the mild inflammatory response elicited by vaccination is benign in pregnancy". Take home, you are being studied to see the effects of the flu vaccine on you, if you are pregnant, and your developing child. And who decides what "mild" is anyways. If you develop preeclampsia and delivery early, where is the "mild" in that?
could the flu vaccine cause a short-term increase in cardiovascular event risk? According to this study yes. So, with a recent study showing no benefit in children and adults, then with this finding of increased arterial dysfunction, increased CRP and fibrinogen, and increased LDL oxidation...why would an adult get the flu vaccine???
The focus should be on what the science shows, not an individuals bias!
Asthma associated with low selenium, low zinc, high copper, low glutathione peroxidase, glutathione reductase, and catalase activity; in contrast, increased hs-CRP, and TBARS was noted. Interesting that FEV1 and FVC positively correlated with Se levels.
nice review, older, of ischemic stroke risk and ways to prevent/heal in a more integrative approach. Good review of risk associated with hs-CRP and homocysteine as well.
this study showed that oral testosterone did not increase CRP. This is a different finding than other studies. I question the use of the oral testosterone due to first pass metabolism. This would result in less testosterone reaching the peripheral sites of aromatase activity.
Estradiol found to be associated with elevated CRP and fibrinogen with men. This association was not found between Testosterone and the same inflammatory markers. This points to the conversion of Testosterone to estrogen as a contributor to inflammation and CVD in men.
Women with PCOS have associated increased inflammation. This origin is primarily via adipose tissue and associate adipocytokines (TNF-alpha, and IL-6). CRP elevation, as found in this study, is associated with increased CVD.