Association of Low Serum Free Testosterone with Carotid Atherosclerosis in Male.

The cross sectional descriptive type of observational study was aimed to evaluate the association of serum free testosterone in 59 patients of carotid atherosclerotic male {<50% stenosis (n=26); >50% stenosis (n=33) } from March 2015 to February 2016 in the Department of Radiology & Imaging of Bangabandhu Sheikh Mujib Medical University (BSMMU) & National Institute of Neurosciences (NINS), Dhaka, Bangladesh. Twenty seven patients who had normal carotid doppler findings were taken as control. Serum total testosterone and sex hormone binding globulin was measured by chemiluminescence micro particle immunoassay and free testosterone was done by using Vermeulen formula. Concentration of free testosterone differed significantly among groups (p=0.004) and it was significantly lower in <50% stenosed group. Logistic regression analysis revealed that low free testosterone (free testosterone ≤0.24 nmol/L) was independently associated with development of carotid atherosclerosis (p=0.04, OR 3.07, 95% CI 1.14-9.30). In conclusion low serum free testosterone was associated with carotid atherosclerosis in male.

Involvement of endothelin-1 in habitual exercise-induced increase in arterial compliance.

AIM: Habitual aerobic exercise results in a significant increase in central arterial compliance. Endothelin-1 (ET-1) is a potent endothelium-derived vasoconstrictor peptide and could play a role in mediating the habitual aerobic exercise-induced increase in central arterial compliance. The aim of the present study was to examine whether ET-1 is involved in the mechanisms underlying the increase in central arterial compliance with aerobic exercise training. METHODS: Seven apparently healthy middle-aged and older (60 +/- 3 years) adults underwent systemic endothelin-A/B (ET(A/B))-receptor blockade (500 mg of Tracleer) before and after 12 weeks of aerobic exercise training (70 +/- 1% of maximal heart rate, 44 +/- 2 min day(-1), 4.4 +/- 0.1 days week(-1)). RESULTS: Basal carotid arterial compliance (via simultaneous B-mode ultrasound and arterial applanation tonometry on the common carotid artery) increased significantly after exercise training. Resting plasma ET-1 concentration decreased significantly after exercise training. Before exercise intervention, carotid arterial compliance increased significantly with the administration of the ET(A/B)-receptor blockade. After training, however, increases in carotid arterial compliance previously observed with the ET(A/B)-receptor blockade before training were abolished. CONCLUSIONS: Regular aerobic exercise training enhances central arterial compliance in middle-aged and older humans. The increase in arterial compliance was associated with the corresponding reduction in plasma ET-1 concentration as well as the elimination of ET-1-mediated vascular tone. These results suggest that reductions in ET-1 may be an important mechanism underlying the beneficial effect of exercise training on central artery compliance.

Estrogen enhances wound healing in the penis of rats.

Estrogen receptor (ER) alpha and beta and aromatase are expressed in various cell-types and compartments of the penis, including the epidermis of glans penis. Here, we hypothesize that estrogen helps maintain the viability and integrity of glans penis and test the hypothesis by treating lesioned glans penis with either 17beta-estradiol or vehicle only. Estrogen was found to facilitate wound healing and increase vascular endothelial growth factor (VEGF) immunoreactivity compared to control, as revealed by scanning electron microscopy, histology, and immunohistochemistry. We conclude that estrogen plays a role in maintaining glans penis integrity, in part, by facilitating penile healing, possibly via up-regulating VEGF levels.

The penis: a new target and source of estrogen in male reproduction.

In the past decade, interest and knowledge in the role of estrogen in male reproduction and fertility has gained significant momentum. More recently, the cellular distribution and activity of estrogen receptors (alpha and beta)(ER) and aromatase (estrogen synthesis) has been reported in the penis, making the penis the latest "frontier" in the study of estrogen in male reproduction. ER and aromatase are broadly and abundantly expressed in various penile compartments and cell types (erectile tissues, urethral epithelia, vascular and neuronal cells), suggesting the complexity and significance of the estrogen-ER system in penile events. Unraveling this complexity is important and will require utilization of the various resources that are now at our disposal including, animal models and human lacking or deficient in ER and aromatase and the use of advanced and sensitive techniques. Some of the obvious areas that require our attention include: 1) a comprehensive mapping of ER-alpha and -beta cellular expression in the different penile compartments and subpopulations of cells, 2) delineation of the specific roles of estrogen in the different subpopulations of cells, 3) establishing the relationship of the estrogen-ER system with the androgen-androgen receptor system, if any, and 4) characterizing the specific penile phenotypes in human and animals lacking or deficient in estrogen and ER. Some data generated thus far, although preliminary, appear to challenge the long held dogma that, overall, androgens have a regulatory monopoly of penile development and function.

Acute exercise causes an enhancement of tissue renin-angiotensin system in the kidney in rats.

AIMS: Initially, the renin-angiotensin system (RAS) produced through the classical endocrine pathway was well known for its regulation of blood pressure. However, it was revealed that a local autocrine and/or paracrine RAS may exist in a number of tissues (such as kidney). Exercise causes a redistribution of tissue blood flow, by which the blood flow is greatly increased in active muscles, whereas it is decreased in the splanchnic circulation (such as in the kidney). We hypothesized that exercise causes an enhancement of tissue RAS in the kidney. METHODS: We studied whether exercise affects expression of angiotensinogen and angiotensin-converting enzyme (ACE) and tissue angiotensin II level in the kidney. The rats performed treadmill running for 30-min. Immediately after this exercise, kidney was quickly removed. Control rats remained at rest during this 30-min period. RESULTS: The expression of angiotensinogen mRNA in the kidney was markedly higher in the exercise rats than in the control rats. ACE mRNA in the kidney was significantly higher in the exercise rats than in the control rats. Western blot analysis confirmed significant upregulation of ACE protein in the kidney after exercise. Tissue angiotensin II level was also increased by exercise. CONCLUSION: The present study suggests that the exercise-induced enhancement of tissue RAS in the kidney causes vasoconstriction and hence decreases blood flow in the kidney, which are helpful in increasing blood flow in active muscles, thereby contributing to the redistribution of blood flow during exercise.

Aromatase is abundantly expressed by neonatal rat penis but downregulated in adulthood.

Although synthesis of estrogen by male gonads has been well documented for over half a century, it is only recently that the role of estrogen in male reproductive events has gained appreciation. We recently reported abundant expression of estrogen receptor (ER)-alpha and -beta in different cell types of the rat penis, whose levels diminished with advancing age. The present study, which builds on data from the ER study, was designed to determine whether the penis is capable of generating its own local estrogen by examining evidence of the expression of aromatase, a microsomal enzymatic complex which irreversibly converts androgens to estrogens, using immunohistochemistry, Western blotting, in situ hybridization and real-time PCR analyses. Secondly, the effects of sex steroid hormones on penile aromatase were examined. Discrete aromatase immunoreactive cells were localized in primordial corpus cavernosum, corpus spongiosus and os penis, blood vessels and sensory corpuscle of glans penis. In situ hybridization signals corresponded with immunohistochemical findings. Western blot, enzyme immunoassay and real-time PCR analyses of rat penile samples revealed an age-dependent expression of aromatase and estrogen, with levels at week 1 almost resembling those of the ovary, but they decreased sharply by week 8, and decreased further by week 35. This expression pattern was strikingly similar to that of ER-alpha reported previously. Testosterone and diethylstilbesterol administered prenatally upregulate levels of aromatase mRNA and protein, and estrogen postnatally. Dihydrotestosterone upregulated aromatase mRNA and protein, but not estrogen. We conclude that estrogen acts via ER in a paracrine and/or autocrine manner to regulate penile events, particularly during development, and that estrogen synthesis is regulated by estrogen and androgens.

Characterization of vascular endothelial growth factor (VEGF) in the uterine cervix over pregnancy: effects of denervation and implications for cervical ripening.

Bilateral neurectomy of the pelvic nerve (BLPN) that carries uterine cervix-related sensory nerves induces dystocia, and administration of its vasoactive neuropeptides induces changes in the cervical microvasculature, resembling those that occur in the ripening cervix. This study was designed to test the hypothesis that (a) the cervix of pregnant rats expresses vascular endothelial growth factor (VEGF) and components of the angiogenic signaling pathway [VEGF receptors (Flt-1, KDR), activity of protein kinase B, Akt (phosphorylated Akt), and endothelial nitric oxide synthase (eNOS)] and von Willebrand Factor (vWF) and that these molecules undergo changes with pregnancy, and (b) bilateral pelvic neurectomy (BLPN) alters levels of VEGF concentration in the cervix. Using RT-PCR and sequencing, two VEGF isoforms, 120 and 164, were identified in the rat cervix. VEGF, VEGF receptor-1 (Flt-1), eNOS, and vWF immunoreactivities (ir) were localized in the microvasculature of cervical stroma. Their protein levels increased during pregnancy but decreased to control levels by 2 days postpartum. VEGF receptor-2 (KDR)-ir was confined to the epithelium of the endocervix. BLPN downregulated levels of VEGF by a third. Therefore, the components of the angiogenic signaling pathway are expressed in the cervix and change over pregnancy. Furthermore, angiogenic and sensory neuronal factors may be important in regulating the dynamic microvasculature in the ripening cervix and may subsequently play a role in cervical ripening and the birth process.

Diminished penile expression of vascular endothelial growth factor and its receptors at the insulin-resistant stage of a type II diabetic rat model: a possible cause for erectile dysfunction in diabetes.

Erectile dysfunction (ED) is commonly experienced in men with diabetes mellitus. Vascular endothelial growth factor (VEGF) has been extensively documented for its pathogenic significance in different complications of diabetes. We hypothesized that expressions of VEGF, its receptors and its signaling pathway Akt may be drastically altered in diabetic penile tIssues and their alterations may modulate penile expression of the molecules that are believed to play a role in diabetic ED. Otsuka Long-Evans Fatty (OLETF) rats, a type II (non-insulin-dependent) diabetes mellitus, were used at the insulin-resistant stage of type II diabetes (20 weeks of age). We determined protein and mRNA expressions of VEGF, its receptors, Akt, nitric oxide synthase isoforms, and apoptosis-related molecules in the penis using immunohistochemistry, Western blotting, in situ hybridization, and real-time quantitative PCR analyses. The penile sections were also submitted to the Tdt-mediated dUTP nick end labeling assay for apoptosis. OLETF rats showed marked reductions in penile expression of VEGF, its two receptors and Akt. In OLETF rat penises, endothelial and neuronal nitric oxide synthase isoforms were expressed less abundantly. Furthermore, while anti-apoptotic markers, Bcl-2 and phosphorylated Bad, were down-regulated, pro-apoptotic markers, active caspase-3 and Bax, were up-regulated, resulting in the appearance of apoptotic cells in the penile tIssues of OLETF rats. The VEGF signaling system would work less well in diabetic penile tIssues as a result of the reduced expression, leading to diminished endothelial production of nitric oxide and apoptosis-related erectile tIssue damage. We propose that the abnormalities of the VEGF signaling system in the penis may play a role in the pathophysiology of diabetic ED.

Long-acting calcium channel blocker benidipine suppresses expression of angiogenic growth factors and prevents cardiac remodelling in a Type II diabetic rat model.

AIMS/HYPOTHESIS: Calcium channel blockers, widely used for the treatment of hypertension and angina, could prevent cardiovascular complications in patients with diabetes. They can improve cardiac remodelling in animal models of a variety of cardiovascular diseases. Here, we examined the therapeutic effect of benidipine, a long-acting calcium channel blocker, on cardiac remodelling in Otsuka-Long-Evans-Tokushima-Fatty (OLETF) rats, a Type II (non-insulin-dependent) diabetes mellitus model. METHODS: The methods for morphometric analysis included double staining for coronary capillaries, dye-binding staining for collagen content and Masson's trichrome staining for perivascular fibrosis. Immunohistochemical and in situ hybridization techniques were used for detecting protein and mRNA expressions for vascular endothelial growth factors (VEGF), basic fibroblast growth factors (bFGF) and TGF-beta(1), endothelial nitric oxide synthase (eNOS), and anti- and pro-apoptotic markers. RESULTS: OLETF rats showed an increased coronary capillary density, a reduced venular capillary proportion, an increased cardiac collagen content and prominent cardiac perivascular fibrosis. In OLETF rat hearts, significant increases in vascular expressions for VEGF, bFGF and TGF- beta(1) were found. Furthermore, the apoptosis signalling pathways, involving eNOS and apoptotic markers, were markedly altered, and coronary endothelial cell apoptosis was lower. These alterations with the exception of eNOS expression were significantly blocked by benidipine treatment. CONCLUSION/INTERPRETATION: The suppressive effect of benidipine on overproduction of angiogenic growth factors could prevent cardiac angiogenesis and fibrosis, resulting in an improvement of cardiac remodelling in diabetes. As VEGF and bFGF potently block endothelial cell apoptosis execution, physiological apoptosis revived by benidipine treatment could also contribute to coronary vessel regression.