Testosterone replacement therapy promotes angiogenesis after acute myocardial infarction by enhancing expression of cytokines HIF-1a, SDF-1a and VEGF

Research progress on the protective effect of hormones and hormone drugs in myocardial ischemia-reperfusion injury

Ischemic heart disease (IHD) is a condition where the heart muscle does not receive enough blood flow, leading to cardiac dysfunction. Restoring blood flow to the coronary artery is an effective clinical therapy for myocardial ischemia. This strategy helps lower the size of the myocardial infarction and improves the prognosis of patients. Nevertheless, if the disrupted blood flow to the heart muscle is restored within a specific timeframe, it leads to more severe harm to the previously deprived heart tissue. This condition is referred to as myocardial ischemia/reperfusion injury (MIRI). Until now, there is a dearth of efficacious strategies to prevent and manage MIRI. Hormones are specialized substances that are produced directly into the circulation by endocrine organs or tissues in humans and animals, and they have particular effects on the body. Hormonal medications utilize human or animal hormones as their active components, encompassing sex hormones, adrenaline medications, thyroid hormone medications, and others. While several studies have examined the preventive properties of different endocrine hormones, such as estrogen and hormone analogs, on myocardial injury caused by ischemia-reperfusion, there are other hormone analogs whose mechanisms of action remain unexplained and whose safety cannot be assured. The current study is on hormones and hormone medications, elucidating the mechanism of hormone pharmaceuticals and emphasizing the cardioprotective effects of different endocrine hormones. It aims to provide guidance for the therapeutic use of drugs and offer direction for the examination of MIRI in clinical therapy.

CXCL12 Neutralizing Antibody Promotes Hair Growth in Androgenic Alopecia and Alopecia Areata

We had previously investigated the expression and functional role of C-X-C Motif Chemokine Ligand 12 (CXCL12) during the hair cycle progression. CXCL12 was highly expressed in stromal cells such as dermal fibroblasts (DFs) and inhibition of CXCL12 increased hair growth. Therefore, we further investigated whether a CXCL12 neutralizing antibody (αCXCL12) is effective for androgenic alopecia (AGA) and alopecia areata (AA) and studied the underlying molecular mechanism for treating these diseases. In the AGA model, CXCL12 is highly expressed in DFs. Subcutaneous (s.c.) injection of αCXCL12 significantly induced hair growth in AGA mice, and treatment with αCXCL12 attenuated the androgen-induced hair damage in hair organ culture. Androgens increased the secretion of CXCL12 from DFs through the androgen receptor (AR). Secreted CXCL12 from DFs increased the expression of the AR and C-X-C Motif Chemokine Receptor 4 (CXCR4) in dermal papilla cells (DPCs), which induced hair loss in AGA. Likewise, CXCL12 expression is increased in AA mice, while s.c. injection of αCXCL12 significantly inhibited hair loss in AA mice and reduced the number of CD8+, MHC-I+, and MHC-II+ cells in the skin. In addition, injection of αCXCL12 also prevented the onset of AA and reduced the number of CD8+ cells. Interferon-γ (IFNγ) treatment increased the secretion of CXCL12 from DFs through the signal transducer and activator of transcription 3 (STAT3) pathway, and αCXCL12 treatment protected the hair follicle from IFNγ in hair organ culture. Collectively, these results indicate that CXCL12 is involved in the progression of AGA and AA and antibody therapy for CXCL12 is promising for hair loss treatment.

Microbiota-derived imidazole propionate inhibits type 2 diabetic skin wound healing by targeting SPNS2-mediated S1P transport

Imidazole propionate (ImP) is a recently discovered metabolite of T2DM-related gut microbiota. The effect of ImP on T2DM wound healing has not been studied yet. In this research, the changes of ImP-producing bacteria on the skin are firstly evaluated. 16sRNA sequencing results showed that the abundance of ImP-producing bacteria-Streptococcus in the intestine and skin of T2DM mice is significantly increased. Animal experiments show that ImP can inhibit the process of wound healing and inhibit the formation of blood vessels in the process of wound healing. Molecular mechanism research results show that ImP can inhibit S1P secretion mediated by SPNS2, and inhibit the activation of Rho signaling pathway, thereby affecting the angiogenesis process of HUVEC cells. This work also provides a potential drug HMPA that promotes T2DM wound healing.

Anti-angiogenic effect of exo-LncRNA TUG1 in myocardial infarction and modulation by remote ischemic conditioning

The successful use of exosomes in therapy after myocardial infarction depends on an improved understanding of their role in cardiac signaling and regulation. Here, we report that exosomes circulating after myocardial infarction (MI) carry LncRNA TUG1 which downregulates angiogenesis by disablement of the HIF-1α/VEGF-α axis and that this effect can be counterbalanced by remote ischemic conditioning (RIC). Rats with MI induced through left coronary artery ligation without (MI model) and with reperfusion (ischemia/reperfusion I/R model) were randomized to RIC, or MI (I/R) or sham-operated (SO) control. Data from one cohort study and one randomized-controlled trial of humans with MI were also utilized, the former involving patients who had not received percutaneous coronary intervention (PCI) and the latter patients with PCI. Exosome concentrations did not differ between intervention groups (RIC vs. control) in rats (MI and I/R model) as well as humans (with and without PCI). However, MI and I/R exosomes attenuated HIF-1α, VEGF-α, and endothelial function. LncRNA TUG1 was increased in MI and I/R exosomes, but decreased in SO and RIC exosomes. HIF-1α expression was downregulated with MI and I/R exosomes but increased with RIC exosomes. Exosome inhibition suppressed HIF-1α upregulation through RIC exosomes. VEGF-α was identified as HIF-1α-regulated target gene. Knockdown of HIF-1α decreased VEGF-α, endothelial cell capability, and tube formation. Overexpression of HIF-1α exerted opposite effects. Transfection and co-transfection of 293 T cells with exosome-inhibitor GW4869 and HIF-1α inhibitor si-HIF-1α confirmed the exosomal-LncRNA TUG1/HIF-1α/VEGF-α pathway. LncRNA TUG1 is a potential therapeutic target after MI with or without reperfusion through PCI.

The impact of aging and physical training on angiogenesis in the musculoskeletal system

Angiogenesis is the physiological process of capillary growth. It is strictly regulated by the balanced activity of agents that promote the formation of capillaries (pro-angiogenic factors) on the one hand and inhibit their growth on the other hand (anti-angiogenic factors). Capillary rarefaction and insufficient angiogenesis are some of the main causes that limit blood flow during aging, whereas physical training is a potent non-pharmacological method to intensify capillary growth in the musculoskeletal system. The main purpose of this study is to present the current state of knowledge concerning the key signalling molecules implicated in the regulation of skeletal muscle and bone angiogenesis during aging and physical training.

ERK/HIF-1α/VEGF pathway: a molecular target of ELABELA (ELA) peptide for attenuating cardiac ischemia-reperfusion injury in rats by promoting angiogenesis

BACKGROUND

Myocardial ischemia-reperfusion (I/R) injury is caused by a chain of events such as endothelial dysfunction. This study was conducted to investigate protective effects of ELABELA against myocardial I/R in Wistar rats and clarify its possible mechanisms. METHODS AND RESULTS: MI model was established based on the left anterior descending coronary artery ligation for 30 min. Then, 5 µg/kg of ELA peptide was intraperitoneally infused in rats once per day for 4 days. Western blot assay was used to assay the expression of t-ERK1/2, and p-ERK1/2 in different groups. The amount of myocardial capillary density, the expression levels of VEGF and HIF-1α were evaluated using immunohistochemistry assay. Masson's trichrome staining was utilized to assay cardiac interstitial fibrosis. The results showed that establishment of MI significantly enhanced cardiac interstitial fibrosis and changed p-ERK1/2/ t-ERK1/2 ratio. Likewise, ELA post-treatment markedly increased myocardial capillary density, the expression of several angiogenic factors (VEGF-A, HIF-1α), and reduced cardiac interstitial fibrosis by activation of ERK1/2 signaling pathways.

CONCLUSION

Collectively, ELA peptide has ability to reduce myocardial I/R injury by promoting angiogenesis and reducing cardiac interstitial fibrosis through activating ERK/HIF-1α/VEGF pathway.

LRG1 promotes hypoxia-induced cardiomyocyte apoptosis and autophagy by regulating hypoxia-inducible factor-1α

Cardiomyocyte apoptosis and autophagy play important roles in acute myocardial infarction (AMI), but the effect of leucine-rich alpha-2-glycoprotein 1 (LRG1) on the apoptosis and autophagy of H9c2 has not yet been reported. It was found through differential gene analysis and LASSO analysis that LRG1 was the key gene in AMI. In this study, western blot was applied to detect the protein expression of Bax, Bcl2, LC3, p62, LRG1 and hypoxia-inducible factor-1α (HIF-1α); CCK-8 assay was employed to detect cell viability; Annexin V-FITC/PI staining was adopted to evaluate apoptosis, and immunofluorescence assay was applied to detect autophagy. Under hypoxia conditions in H9c2 cells, LRG1 protein levels were increased, the cell activity was decreased, and apoptosis and autophagy were promoted; the downregulated LRG1 significantly enhanced cell viability but inhibited apoptosis and autophagy. When knocking down HIF-1α in the overexpressed LRG1 cells, the effects of LRG1 were reversed under hypoxia condition. In conclusion, LRG1/HIF-1α promoted H9c2 cell apoptosis and autophagy in hypoxia, potentially providing new ideas for the determination and treatment of AMI.

Abbreviation: LRG1: Leucine-rich alpha-2-glycoprotein 1; LRR: leucine-rich repeat; HIF-1α: Hypoxia-inducible factor-1α; AMI: acute myocardial infarction

Gastrin mediates cardioprotection through angiogenesis after myocardial infarction by activating the HIF-1α/VEGF signalling pathway

Acute myocardial infarction (MI) is one of the leading causes of death in humans. Our previous studies showed that gastrin alleviated acute myocardial ischaemia-reperfusion injury. We hypothesize that gastrin might protect against heart injury after MI by promoting angiogenesis. An MI model was simulated by ligating the anterior descending coronary artery in adult male C57BL/6J mice. Gastrin was administered twice daily by intraperitoneal injection for 2 weeks after MI. We found that gastrin reduced mortality, improved myocardial function with reduced infarct size and promoted angiogenesis. Gastrin increased HIF-1α and VEGF expression. Downregulation of HIF-1α expression by siRNA reduced the proliferation, migration and tube formation of human umbilical vein endothelial cells. These results indicate that gastrin restores cardiac function after MI by promoting angiogenesis via the HIF-1α/VEGF pathway.

Activation of CXCR7 alleviates cardiac insufficiency after myocardial infarction by promoting angiogenesis and reducing apoptosis

Angiogenesis is an important pathway for revascularization of ischemic tissues after acute myocardial infarction (AMI). It is unclear what role CXCR7 plays in angiogenesis in the ischemic area after AMI, although some researchers have shown that the activation of CXCR7 protectsthe heart under those conditions. Here, we hypothesize that the activation of CXCR7 promotes angiogenesis, reduces cell apoptosis and alleviates cardiac deficiency after AMI. C57BL/6 J mice were subjected to AMI and treated with TC14012 (10 mg/kg) for 24 days. HUVECs were cultured in a hypoxic (2% O₂) environment to generate a model of hypoxia. CXCR7 was knocked down in HUVECs by sh-CXCR7 transfection, and CXCR7 was activated by TC14012 (30 μM) treatment. The results showed that CXCR7 was downregulated in infarcted heart tissue and hypoxic HUVECs. The global activation of CXCR7 may alleviate the decrease in cardiac function indexes - (ejection fraction and fraction shortening), and reduce infarct size after AMI.. Moreover, CXCR7 activation has been shown to enhance the level of angiogenesis in ischemic heart tissue. In vitro, hypoxia-induced angiogenic functional loss and apoptosis are aggravated by CXCR7 knockdown in HUVECs. Both angiogenic impairment and cell apoptosis are rescued by CXCR7 activation. In conclusion, the present study indicates that activation of CXCR7 plays an important protective role for ischemic cells in hypoxic endothelial cells and AMI model mice by promoting angiogenesis and reducing apoptosis, which suggests that CXCR7 may be a potential therapeutic target to rescue the ischemic myocardium..

Recipient-Site Preconditioning with Deferoxamine Increases Fat Graft Survival by Inducing VEGF and Neovascularization in a Rat Model

BACKGROUND

The authors hypothesize that ischemic preconditioning of the recipient site with deferoxamine will increase fat graft survival by enhancing angiogenesis in a rat model.

METHODS

Cell viability, tube formation, and mRNA expression were measured in human umbilical vein endothelial cells treated with deferoxamine. A total of 36 rats were then used for an in vivo study. A dose of 100 mg/kg of deferoxamine was injected subcutaneously into the rat scalp every other day for five treatments. On the day after the final injection, the scalp skin was harvested from half the animals to evaluate the effects of deferoxamine on the recipient site. In the remaining animals, inguinal fat tissue was transplanted to the scalp. Eight weeks after transplantation, the grafts were harvested to evaluate the effects of deferoxamine preconditioning on fat graft survival.

RESULTS

In human umbilical vein endothelial cells, treatment with a deferoxamine concentration higher than 400 μM decreased cell viability compared with the control (p = 0.002). Treatment with 100 and 200 μM deferoxamine increased endothelial tube formation (p = 0.001) and mRNA levels of angiogenesis-related factors (p = 0.02). Rat scalps treated with deferoxamine exhibited increased capillary neoformation (p = 0.001) and vascular endothelial growth factor protein expression (p = 0.024) compared with controls. Fat graft volume retention, capillary density (p < 0.001), and adipocyte viability (p < 0.001) in the grafted fat increased when the recipient site was preconditioned with deferoxamine.

CONCLUSION

This study demonstrated that recipient site preconditioning with deferoxamine increases fat graft survival by inducing vascular endothelial growth factor and neovascularization.

Evaluation the effect of testosterone on the number of endothelial progenitor cells and amount of SDF-1α, PDGF, bFGF, and NO

Background:

Recent therapeutic advances in cardiovascular disease, thanks to the discovery of endothelial progenitor cells (EPCs). Stromal cell-derived factor-1α (SDF-1α), platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), and nitric oxide (NO) play a role in migration, homing, and differentiation of EPCs into mature endothelial cells. The incidence of cardiovascular disease is higher in men than in women. This fact suggests the influence of sex hormones on incidence of cardiovascular disease.

Methods:

Twenty-four female wistar rats weighing 160–180 g were randomly divided into four groups (N = 6): 1. sham-treated by sesame oil, 2. ovariectomized (OVX)-treated by sesame oil, 3. OVX-treated by 10 μg/kg/day testosterone, and 4. OVX-treated by 100 μg/kg/day testosterone. After 21 days, the animals were euthanized and blood samples were saved for determination of EPC count and serum levels of SDF-1α, PDGF, bFGF, and NO production.

Results:

High-dose testosterone induced significant increase in EPC count in OVX rats (P < 0.05). Also 100 μg/kg/day testosterone increased serum level of SDF-1α more than OVX-treated by 10 μg/kg/day testosterone (P < 0.05). But 10 μg/kg/day testosterone increased significantly the serum level of PDGF >100 μg/kg/day testosterone-treated group (P < 0.05). The serum level of bFGF in sham-treated by sesame oil was equal with its concentration in OVX-treated by 100 μg/kg/day testosterone. And the serum concentration of NO production in testosterone-treated groups were significantly less than other groups (P < 0.05).

Conclusions:

This study suggests that testosterone might be effective on cardiovascular disease in females by increasing EPC count through SDF-1α and PDGF mechanisms which are some of the vascular healing factors.

Systemic effects of the hormonal treatment of male hypogonadism with preliminary indications for the management of COVID-19 patients

Male hypogonadism, defined as an inadequate production of testosterone (T), is associated with a greater morbidity and mortality. Epidemiological studies identified T deficiency as a risk factor for cardiovascular disease. Also, low serum T levels impact on glucose homeostasis through a worse glucose uptake, utilization, and disposal, and the general negative impact on metabolism. The aim of this review is to provide a comprehensive and updated overview of the effects of T replacement therapy on metabolic and cardiovascular systems and prostate tissue in patients with hypogonadism, including molecular mechanisms through which T exerts its actions. Furthermore, recent findings on novel coronavirus disease (COVID-19) epidemiology have shown a greater mortality in male compared with female patients and a role of T in promoting the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection of the host cells has been demonstrated. Hence, the secondary aim of this review is to provide preliminary indications on the management in patients with COVID-19.

Sex differences in corneal neovascularization in response to superficial corneal cautery in the rat

Sex-based differences in susceptibility have been reported for a number of neovascular ocular diseases. We quantified corneal neovascularization, induced by superficial silver nitrate cautery, in male and female inbred albino Sprague-Dawley, inbred albino Fischer 344, outbred pigmented Hooded Wistar and inbred pigmented Dark Agouti rats of a range of ages. Corneal neovascular area was quantified on haematoxylin-stained corneal flatmounts by image analysis. Pro-and anti-angiogenic gene expression was measured early in the neovascular response by quantitative real-time polymerase chain reaction. Androgen and estrogen receptor expression was assessed by immunohistochemistry. Male rats from all strains, with or without ocular pigmentation, exhibited significantly greater corneal neovascular area than females: Sprague-Dawley males 43±12% (n = 8), females 25±5% (n = 12), p = 0.001; Fischer 344 males 38±10% (n = 12) females 27±8% (n = 8) p = 0.043; Hooded Wistar males 32±6% (n = 8) females 22±5% (n = 12) p = 0.002; Dark Agouti males 37±11% (n = 9) females 26±7% (n = 9) p = 0.015. Corneal vascular endothelial cells expressed neither androgen nor estrogen receptor. The expression in cornea post-cautery of Cox-2, Vegf-a and Vegf-r2 was significantly higher in males compared with females and Vegf-r1 was significantly lower in the cornea of males compared to females, p<0.001 for each comparison. These data suggest that male corneas are primed for angiogenesis through a signalling nexus involving Cox-2, Vegf-a, and Vegf receptors 1 and 2. Our findings re-enforce that pre-clinical animal models of human diseases should account for sex-based differences in their design and highlight the need for well characterized and reproducible pre-clinical studies that include both male and female animals.

Voluntary wheel running and testosterone replacement increases heart angiogenesis through miR-132 in castrated diabetic rats

OBJECTIVE

Low levels of testosterone in men with diabetes are associated with cardiovascular complications. We investigated the effect of testosterone and voluntary exercise on heart angiogenesis in castrated diabetic rats.

METHODS

Sixty-three diabetic rats were treated with testosterone 2 mg/kg/day or voluntary exercise alone or combination of these two for 6 weeks. At the end of the study, heart tissue samples were collected and used for CD31 detection by immunohistochemical method and determination of miR-132 levels.

RESULTS

miR-132 levels and CD31 of heart tissue were higher after testosterone administration and in the voluntary exercise group in diabetic rats after 6 weeks. Combination of testosterone and voluntary exercise had synergistic effect on angiogenesis and miR-132 level. In castrated diabetic rats, there were significantly lower levels of miR-132 and CD31 in heart tissue compared to the diabetic group, whereas testosterone and exercise reversed these effects. In addition, testosterone supplementation plus exercise had an additive effect on miR-132 levels and CD31 in castrated diabetic rats.

CONCLUSIONS

It was concluded that castration in rats leads to reduced miR-132 levels and subsequently decreased angiogenesis in diabetes. Testosterone plus voluntary exercise improved angiogenesis possibly through enhancement of miR-132 levels in heart of castrated diabetic rats.

Circulating miRNA Profiling of Women at High Risk for Ovarian Cancer

Survival of epithelial ovarian cancer patients remains poor without significant change over many decades. There is a need to better identify women at high risk (HR) for ovarian cancer. We propose that miRNA dysregulation may play critical roles in the early stages of ovarian cancer development. Circulating miRNAs may represent an important biomarker in this context, and miRNA profiling of serum in women at HR compared to those at low risk (LR) may give insights in tumor initiation pathways. There is also rationale for a specific focus on regulation of the androgen and its related hypoxia pathways in tumor initiation. We hypothesized that subsets of these pathway related miRNAs may be downregulated in the HR state. Serum from four HR and five LR women were sequenced and analyzed for 2083 miRNAs. We found 137 miRNAs dysregulated between the HR and LR groups, of which 36 miRNAs were overexpressed in HR and the vast majority (101 miRNAs or 74%) downregulated in the HR, when compared to LR serum. mRNA targets for the differentially expressed miRNAs were analyzed from three different miRNA-mRNA interaction resources. Functional association analysis of hypoxia and androgen pathway mRNA targets of dysregulated miRNAs in HR serum revealed that all but one of the miRNAs that target 52 hypoxia genes were downregulated in HR compared to LR serum. Androgen pathway analysis also had a similar expression pattern where all but one of the miRNAs that target these 135 identified genes were downregulated in HR serum. Overall, there were 91 differentially expressed miRNA-mRNA pairings in the hypoxia analysis. In the androgen-related analysis, overall, there were 429 differentially expressed miRNA-mRNA pairs. Our pilot study suggests that almost all miRNAs that are conserved and/or validated are downregulated in the HR compared to LR serum. This study, which requires validation, suggests that, via miRNA dysregulation, involvement of both hypoxia and its related androgen pathways may contribute to the HR state. This pilot study is the first report to our knowledge that studies circulating miRNA profiling of HR and LR women.

Hypoxia changes chemotaxis behaviour of mesenchymal stem cells via HIF-1α signalling

Mesenchymal stem cells (MSCs) have drawn great attention because of their therapeutic potential. It has been suggested that intra‐venous infused MSCs could migrate the site of injury to help repair the damaged tissue. However, the mechanism for MSC migration is still not clear so far. In this study, we reported that hypoxia increased chemotaxis migration of MSCs. At 4 and 6 hours after culturing in hypoxic (1% oxygen) conditions, the number of migrated MSCs was significantly increased. Meanwhile, hypoxia also increased the expression of HIF‐1α and SDF‐1. Using small interference RNA, we knocked down the expression of HIF‐1α in MSCs to study the role of HIF‐1α in hypoxia induced migration. Our data indicated that knocking down the expression of HIF‐1α not only abolished the migration of MSCs, but also reduced the expression of SDF‐1. Combining the results of migration assay and expression at RNA and protein level, we demonstrated a novel mechanism that controls the increase of MSCs migration. This mechanism involved HIF‐1α mediated SDF‐1 expression. These findings provide new insight into the role of HIF‐1α in the hypoxia induced MSC migration and can be a benefit for the development of MSC‐based therapeutics for wound healing.

Combined low-dose testosterone and vildagliptin confers cardioprotection in castrated obese rats

Although a physiological dose of testosterone replacement therapy (p-TRT) has been shown to improve left ventricular (LV) function, some studies reported that it increased the risk of myocardial infarction in testosterone-deprived men. We previously reported that vildagliptin might be used as an alternative to the p-TRT. In this study, we hypothesized that a combined low-dose TRT with vildagliptin exerts greater efficacy than single regimen in improving cardiometabolic function in obese-insulin resistant rats with testosterone deprivation. Male rats were fed on a normal diet or high-fat diet for 12 weeks. Then, they were divided into 2 subgroups; sham operation and orchiectomy (NDO, HFO) and fed their diets for another 12 weeks. At week 25, orchiectomized rats were subdivided into 4 groups, vehicle, p-TRT, vildagliptin, and combined drugs. At week 29, cardiometabolic and biochemical parameters were determined. HFO rats had obese-insulin resistance with a worse LV dysfunction, compared with sham. Vildagliptin and combined drugs effectively reduced insulin resistance. All treatments reduced blood pressure, cardiac autonomic imbalance, LV dysfunction, mitochondrial dysfunction, apoptosis, and increased mitochondrial fusion in NDO and HFO rats. However, p-TRT and combined drugs, but not vildagliptin, reduced mitochondrial fission in NDO and HFO rats. We concluded that combined low-dose TRT with vildagliptin mitigated LV function at a similar level to the p-TRT alone and vildagliptin via improving mitochondrial fusion, reducing mitochondrial dysfunction and apoptosis in testosterone-deprived rats. Our findings suggest that low-dose TRT combined with vildagliptin may be an alternative for p-TRT in conditions of obese-insulin resistance with testosterone deprivation.

Hypoxia-Inducible Factor 1 alpha (HIF-1α)/Vascular Endothelial Growth Factor (VEGF) Pathway Participates in Angiogenesis of Myocardial Infarction in Muscone-Treated Mice: Preliminary Study

BACKGROUND Angiogenesis plays a crucial role in myocardial infarction (MI) treatment by ameliorating myocardial remodeling, thus improving cardiac function and preventing heart failure. Muscone has been reported to have beneficial effects on cardiac remodeling in MI mice. However, the effects of muscone on angiogenesis in MI mice and its underlying mechanisms remain unknown. MATERIAL AND METHODS Mice were randomly divided into sham, MI, and MI+muscone groups. The MI mouse model was established by ligating the left anterior descending coronary artery. Mice in the sham group received the same procedure except for ligation. Mice were administered muscone or an equivalent volume of saline for 4 consecutive weeks. Cardiac function was evaluated by echocardiograph after MI for 2 and 4 weeks. Four weeks later, all mice were sacrificed and Masson's trichrome staining was used to assess myocardial fibrosis. Isolectin B4 staining was applied to evaluate the angiogenesis in mouse hearts. Immunohistochemistry, Western blot analysis, and quantitative real-time polymerase chain reaction (qPCR) were performed to analyze expression levels of HIF-1a and its downstream genes. RESULTS Compared with the MI group, muscone treatment significantly improved cardiac function and reduced myocardial fibrosis. Moreover, muscone enhanced angiogenesis in the peri-infarct region and p-VEGFR2 expression in the vascular endothelial cells. Western blot analysis and qPCR showed that muscone upregulated expression levels of HIF-1a and VEGFA. CONCLUSIONS Muscone improved cardiac function in MI mice through augmented angiogenesis. The potential mechanism of muscone treatment in regulating angiogenesis of MI mice was upregulating expression levels of HIF-1α and VEGFA.

Androgen action augments ischemia-induced, bone marrow progenitor cell-mediated vasculogenesis

Bone marrow-derived progenitor cell-mediated vasculogenesis is a key process for vascular repair and regeneration. However, the role of androgens in the mechanism of ischemia-induced vasculogenesis remains unclear. In this study, a gender-mismatch murine bone marrow transplant model was used to allow tissue tracking of transplanted cells. Bone marrow from 2-month-old male mice was transplanted into irradiated age-matched female recipients. Following the transplantation, ovariectomized female recipients were subjected to unilateral hindlimb ischemia and immediately implanted with either dihydrotestosterone (DHT) or placebo pellets. Laser Doppler perfusion imaging revealed that DHT significantly augmented blood flow recovery, with increased capillary density compared to placebo-treated female recipient controls. Flow cytometry analysis showed that DHT modulated vasculogenesis by increasing Sca1+/CXC4+ progenitor cell production in bone marrow and spleen and enhancing cell mobilization in circulating blood following hindlimb ischemia. Bone marrow cell homing was examined by detecting expression levels of male-specific SRY gene in the ischemic female tissues. DHT treatment promoted bone marrow cell homing to ischemic tissue shown by significantly higher SRY expression compared to placebo-treated females as well as reduced apoptotic features in DHT-treated females, including increased Bcl-2 expression, reduced Bax levels and decreased TUNEL staining. In conclusion, the gender-mismatched bone marrow transplant study shows that androgens directly enhance bone marrow cell-mediated vasculogenesis that contributes to ischemia-induced neovascularization.

Intrauterine Exposure to Cadmium Reduces HIF-1 DNA-Binding Ability in Rat Fetal Kidneys

During embryonic development, some hypoxia occurs due to incipient vascularization. Under hypoxic conditions, gene expression is mainly controlled by hypoxia-inducible factor 1 (HIF-1). The activity of this transcription factor can be altered by the exposure to a variety of compounds; among them is cadmium (Cd), a nephrotoxic heavy metal capable of crossing the placenta and reaching fetal kidneys. The goal of the study was to determine Cd effects on HIF-1 on embryonic kidneys. Pregnant Wistar rats were exposed to a mist of isotonic saline solution or CdCl₂ (D_Del = 1.48 mg Cd/kg/day), from gestational day (GD) 8 to 20. Embryonic kidneys were obtained on GD 21 for RNA and protein extraction. Results show that Cd exposure had no effect on HIF-1α and prolyl hydroxylase 2 protein levels, but it reduced HIF-1 DNA-binding ability, which was confirmed by a decrease in vascular endothelial growth factor (VEGF) mRNA levels. In contrast, the protein levels of VEGF were not changed, which suggests the activation of additional regulatory mechanisms of VEGF protein expression to ensure proper kidney development. In conclusion, Cd exposure decreases HIF-1-binding activity, posing a risk on renal fetal development.

Clinical progression and metachronous paragangliomas in a large cohort of SDHD germline variant carriers

Although it is well established that paternally transmitted germline variants in SDHD are associated with multifocal paragangliomas and lifelong follow-up is generally advised, the risk of metachronous lesions is presently unknown. In a large Dutch cohort of SDHD variant carriers, we studied the development of new paragangliomas, and the evolution of symptoms and cranial nerve impairment. Recurrent event analysis and the Kaplan-Meier product limit estimator were used to study the risk of new lesions. The relation between several predictors and development of new symptoms was assessed using logistic regression. Of the 222 SDHD variant carriers included, 65% presented with symptoms and 11% with cranial nerve dysfunction. Over a median period of 8 years, 42% reported new symptoms, and new cranial nerve impairment was observed in 11% of subjects. The estimated fraction of subjects that developed new HNPGL increased to 73% (95% CI: 52-85%) after 22 years of follow-up. Males were more likely to develop new HNPGL compared to females (HR: 1.63, 95% CI: 1.10-2.40), as were subjects that presented with symptoms, compared to subjects that were asymptomatic at baseline (HR: 1.61, 95% CI: 1.01-2.55). In addition, the risk of new lesions decreased with number of HNPGL present at first diagnosis (HR: 0.68 and 95% CI: 0.56-0.82). Carriers of a paternally inherited SDHD variant face a considerable risk for new HNPGL. In addition, nearly 50% of subjects reported new symptoms. However, new cranial nerve deficits were observed in only 11%, which is less than reported in surgical series. These risks should be taken into account when considering treatment strategies and counseling.

Caffeic acid phenethyl ester promotes haematopoietic stem/progenitor cell homing and engraftment

Background

Several studies have suggested that caffeic acid phenethyl ester (CAPE) can induce the expression of hypoxia inducible factor-1α (HIF-1α) protein. We determined whether CAPE has a novel function in improving the homing and engraftment of haematopoietic stem/progenitor cells (HSPCs) by regulating HIF-1α gene expression in the bone marrow (BM) niche.

Methods

For survival experiments, lethally irradiated C57BL/6 mice were injected with a low number of BM mononuclear cells (MNCs) and CAPE according to the indicated schedule. Homing efficiency analysis was conducted using flow cytometry and colony-forming unit (CFU) assays. The influence of intraperitoneal injection of CAPE on short-term and long-term engraftment of HSPCs was evaluated using competitive and non-competitive mouse transplantation models. To investigate the mechanism by which CAPE enhanced HSPC homing, we performed these experiments including Q-PCR, western blot, immunohistochemistry and CFU assays after in-vivo HIF-1α activity blockade.

Results

CAPE injection significantly increased the survival rate of recipient mice after lethal irradiation and transplantation of a low number of BM MNCs. Using HSPC homing assays, we found that CAPE notably increased donor HSPC homing to recipient BM. The subsequent short-term and long-term engraftment of transplanted HSPCs was also improved by the optimal schedule of CAPE administration. Mechanistically, we found that CAPE upregulated the expression of HIF-1α, vascular endothelial growth factor-A (VEGF-A) and stromal cell-derived factor 1α (SDF-1α). The HIF-1α inhibitor PX-478 blocked CAPE-enhanced HSPC homing, which supported the idea that HIF-1α is a key target of CAPE.

Conclusions

Our results showed that CAPE administration facilitated HSPC homing and engraftment, and this effect was primarily dependent on HIF-1α activation and upregulation of SDF-1α and VEGF-A expression in the BM niche.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0708-x) contains supplementary material, which is available to authorized users.

THE EFFECT OF TESTOSTERONE AND VOLUNTARY EXERCISE, ALONE OR TOGETHER, ON miRNA-126 EXPRESSION CHANGES IN HEART OF DIABETIC RATS

Methods

Ninety Wistar male rats were used in this study. Type 1 diabetes was induced by i.p injection of 50 mg/kg of streptozotocin in all animals. After 42 days of treatment with testosterone (2mg/kg/day) or voluntary exercise alone or in combination, the heart of the rats has been removed and MicroRNA was extracted from the heart using miRCURYTM RNA isolation kit.

Results

Our results showed that either testosterone or exercise increased miRNA-126 expression levels in the heart of diabetic rats. Treatment of diabetic rats with testosterone and exercise at the same time had a synergistic effect on miRNA-126 levels in the heart. Furthermore, in castrated diabetes group, miRNA-126 levels were significantly decreased in heart, whereas either testosterone treatment or exercise training enhanced expression of this miRNA. Also, simultaneous treatment of castrated diabetic rats with testosterone and exercise had an additive effect on miRNA-126 expression levels.

Conclusion

This study showed that testosterone and exercise promote an increase in the expression of miRNA-126 in the heart tissue and this may be related to cardiac angiogenesis. These results may indicate that testosterone and exercise can help to prevent progression of diabetic cardiomyopathy due to impaired angiogenesis in the heart.

Testosterone and Voluntary Exercise, Alone or Together Increase Cardiac Activation of AKT and ERK1/2 in Diabetic Rats

Background

Impaired angiogenesis in cardiac tissue is a major complication of diabetes. Protein kinase B (AKT) and extracellular signal regulated kinase (ERK) signaling pathways play important role during capillary-like network formation in angiogenesis process.

Objectives

To determine the effects of testosterone and voluntary exercise on levels of vascularity, phosphorylated Akt (P- AKT) and phosphorylated ERK (P-ERK) in heart tissue of diabetic and castrated diabetic rats.

Methods

Type I diabetes was induced by i.p injection of 50 mg/kg of streptozotocin in animals. After 42 days of treatment with testosterone (2mg/kg/day) or voluntary exercise alone or in combination, heart tissue samples were collected and used for histological evaluation and determination of P-AKT and P-ERK levels by ELISA method.

Results

Our results showed that either testosterone or exercise increased capillarity, P-AKT, and P-ERK levels in the heart of diabetic rats. Treatment of diabetic rats with testosterone and exercise had a synergistic effect on capillarity, P-AKT, and P-ERK levels in heart. Furthermore, in the castrated diabetes group, capillarity, P-AKT, and P-ERK levels significantly decreased in the heart, whereas either testosterone treatment or exercise training reversed these effects. Also, simultaneous treatment of castrated diabetic rats with testosterone and exercise had an additive effect on P-AKT and P-ERK levels.

Conclusion

Our findings suggest that testosterone and exercise alone or together can increase angiogenesis in the heart of diabetic and castrated diabetic rats. The proangiogenesis effects of testosterone and exercise are associated with the enhanced activation of AKT and ERK1/2 in heart tissue.

Testosterone and Voluntary Exercise Promote Angiogenesis in Hearts of Rats with Diabetes by Enhancing Expression of VEGF-A and SDF-1a

OBJECTIVES

Impaired angiogenesis in cardiac tissue is a major complication of diabetes. This study was aimed to evaluate the effects of testosterone and voluntary exercise on vascular endothelial growth factor-A (VEGF-A), stromal cell-derived factor 1a (SDF-1a) and myocardial capillary density in heart of rats with diabetes.

METHODS

Type 1 diabetes was induced by intraperitoneal injection of 55 mg/kg of streptozotocin in 80 male Wistar rats. After 42 days of treatment with testosterone (2 mg/kg/day) or voluntary exercise alone or in combination, angiogenesis was determined in the hearts by immunostaining for PECAM-1/CD31. The expressions of VEGF-A and SDF-1a levels in heart were also determined by the ELISA method.

RESULTS

Our results showed that capillary density, VEGF-A and SDF-1a levels in the heart were significantly decreased in castrated rats with diabetes, whereas these effects were reversed by testosterone and exercise. Furthermore, simultaneous treatment of castrated rats with diabetes with testosterone and exercise had a synergistic effect on capillary density, VEGF-A and SDF-1a levels in the heart. In the group with diabetes, either testosterone or exercise increased capillary density, VEGF-A and SDF-1a protein levels in heart tissue. However, the effects of combination therapy in rats with diabetes with testosterone and exercise on capillary density, VEGF-A and SDF-1a levels in the heart was synergistic.

CONCLUSIONS

Our findings suggest that testosterone and exercise can promote neoangiogenesis in rats with diabetes and in castrated rats with diabetes. The proangiogenesis effect of testosterone and exercise is associated with the enhanced expression of VEGF-A and SDF-1a in heart tissue.

Testosterone Replacement Modulates Cardiac Metabolic Remodeling after Myocardial Infarction by Upregulating PPARα

Despite the importance of testosterone as a metabolic hormone, its effects on myocardial metabolism in the ischemic heart remain unclear. Myocardial ischemia leads to metabolic remodeling, ultimately resulting in ATP deficiency and cardiac dysfunction. In the present study, the effects of testosterone replacement on the ischemic heart were assessed in a castrated rat myocardial infarction model established by ligating the left anterior descending coronary artery 2 weeks after castration. The results of real-time PCR and Western blot analyses showed that peroxisome proliferator-activated receptor α (PPARα) decreased in the ischemic myocardium of castrated rats, compared with the sham-castration group, and the mRNA expression of genes involved in fatty acid metabolism (the fatty acid translocase CD36, carnitine palmitoyltransferase I, and medium-chain acyl-CoA dehydrogenase) and glucose transporter-4 also decreased. A decline in ATP levels in the castrated rats was accompanied by increased cardiomyocyte apoptosis and fibrosis and impaired cardiac function, compared with the sham-castration group, and these detrimental effects were reversed by testosterone replacement. Taken together, our findings suggest that testosterone can modulate myocardial metabolic remodeling by upregulating PPARα after myocardial infarction, exerting a protective effect on cardiac function.

Muscle weakness during aging: a deficiency state involving declining angiogenesis

This essay begins by proposing that muscle weakness of old age from sarcopenia is due in large part to reduced capillary density in the muscles, as documented in 9 reports of aged persons and animals. Capillary density (CD) is determined by local levels of various angiogenic factors, which also decline in muscles with aging, as reported in 7 studies of old persons and animals. There are also numerous reports of reduced CD in the aged brain and other studies showing reduced CD in the kidney and heart of aged animals. Thus a waning angiogenesis throughout the body may be a natural occurrence in later years and may account significantly for the lesser ailments (physical and cognitive) of elderly people. Old age is regarded here as a deficiency state which may be corrected by therapeutic angiogenesis, much as a hormonal deficiency can be relieved by the appropriate hormone therapy. Such therapy could employ recombinant angiogenic factors which are now commercially available.

Roles of Testosterone Replacement in Cardiac Ischemia-Reperfusion Injury

Testosterone is an anabolic steroid hormone, which is the major circulating androgen hormone in males. Testosterone levels decreasing below the normal physiological levels lead to a status known as androgen deficiency. Androgen deficiency has been shown to be a major risk factor in the development of several disorders, including obesity, metabolic syndrome, and ischemic heart disease. In the past decades, although several studies from animal models as well as clinical studies demonstrated that testosterone exerted cardioprotection, particularly during ischemia-reperfusion (I/R) injury, other preclinical and clinical studies have shown an inverse relationship between testosterone levels and cardioprotective effects. As a result, the effects of testosterone replacement on the heart remain controversial. In this review, reports regarding the roles of testosterone replacement in the heart following I/R injury are comprehensively summarized and discussed. At present, it may be concluded that chronic testosterone replacement at a physiological dose demonstrated cardioprotective effects, whereas acute testosterone replacement can cause adverse effects in the I/R heart.

Testosterone replacement attenuates mitochondrial damage in a rat model of myocardial infarction

Testosterone can affect cardiovascular disease, but its effects on mitochondrial dynamics in the post-infarct myocardium remain unclear. To observe the effects of testosterone replacement, a rat model of castration-myocardial infarction (MI) was established by ligating the left anterior descending coronary artery 2 weeks after castration with or without testosterone treatment. Expression of mitochondrial fission and fusion proteins was detected by western blot and immunofluorescence 14 days after MI. Cardiac function, myocardial inflammatory infiltration and fibrosis, cardiomyocyte apoptosis, mitochondrial microstructure, and ATP levels were also assessed. Compared with MI rats, castrated rats showed aggravated mitochondrial and myocardial insults, including mitochondrial swelling and disordered arrangement; loss of cristae, reduced mitochondrial length; decreased ATP levels; cardiomyocyte apoptosis; and impaired cardiac function. Results of western blotting analyses indicated that castration downregulated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1A) and mitofusin 2, but upregulated dynamin-related protein 1. The results were also supported by results obtained using immunofluorescence. However, these detrimental effects were reversed by testosterone supplementation, which also elevated the upstream AMP-activated protein kinase (AMPK) activation of PGC1A. Thus, testosterone can protect mitochondria in the post-infarct myocardium, partly via the AMPK-PGC1A pathway, thereby decreasing mitochondrial dysfunction and cardiomyocyte apoptosis. The effects of testosterone were confirmed by the results of ELISA analyses.

Chronic testosterone replacement exerts cardioprotection against cardiac ischemia-reperfusion injury by attenuating mitochondrial dysfunction in testosterone-deprived rats

Background

Although testosterone deficiency is associated with increased risks of heart disease, the benefits of testosterone therapy are controversial. Moreover, current understanding on the cardiac effect of testosterone during cardiac ischemia-reperfusion (I/R) periods is unclear. We tested the hypothesis that testosterone replacement attenuates the impairment of left ventricular (LV) function and heart rate variability (HRV), and reduces the infarct size and arrhythmias caused by I/R injury in orchiectomized (ORX) rats.

Methodology

ORX or sham-operated male Wistar rats (n = 24) were randomly divided and received either testosterone (2 mg/kg, subcutaneously administered) or the vehicle for 8 weeks. The ejection fraction (EF) and HRV were determined at baseline and the 4^th and 8^th week. I/R was performed by left anterior descending coronary artery ligation for 30 minutes, followed by a 120-minute reperfusion. LV pressure, arrhythmia scores, infarct size and cardiac mitochondrial function were determined.

Results

Prior to I/R, EF and HRV were impaired in the ORX group, but were restored in the testosterone-treated group. During I/R, arrhythmia scores and the infarct size were greater, and cardiac mitochondrial function was impaired, whereas the time to 1^st VT/VF onset and the LV end-systolic pressure were decreased in the ORX group when compared to the sham group. Testosterone replacement attenuated the impairment of these parameters in ORX rats during I/R injury, but did not show any benefit or adverse effect in non-ORX rats.

Conclusions

Testosterone replacement restores cardiac function and autonomic regulation, and exerts cardioprotective effects during the I/R period via mitochondrial protection in ORX rats.

Higher androgen bioactivity is associated with excessive erythrocytosis and chronic mountain sickness in Andean Highlanders: a review

Populations living at high altitudes (HA), particularly in the Peruvian Central Andes, are characterised by presenting subjects with erythrocytosis and others with excessive erythrocytosis (EE)(Hb>21 g dl(-1) ). EE is associated with chronic mountain sickness (CMS), or lack of adaptation to HA. Testosterone is an erythropoietic hormone and it may play a role on EE at HA. The objective of the present review was to summarise findings on role of serum T levels on adaptation at HA and genes acting on this process. Men at HA without EE have higher androstenedione levels and low ratio androstenedione/testosterone than men with EE, suggesting low activity of 17beta-hydroxysteroid dehydrogenase (17beta-HSD), and this could be a mechanism of adaptation to HA. Higher conversion of dehydroepiandrosterone to testosterone in men with EE suggests nigher 17beta-HSD activity. Men with CMS at Peruvian Central Andes have two genes SENP1, and ANP32D with higher transcriptional response to hypoxia relative to those without. SUMO-specific protease 1 (SENP1) is an erythropoiesis regulator, which is essential for the stability and activity of hypoxia-inducible factor 1 (HIF-1α) under hypoxia. SENP1 reverses the hormone-augmented SUMOylation of androgen receptor (AR) increasing the transcription activity of AR.In conclusion, increased androgen activity is related with CMS.

Modulation of neointimal lesion formation by endogenous androgens is independent of vascular androgen receptor

Aims

Low androgen levels have been linked with an increased risk of cardiovascular disease in men. Previous studies have suggested that androgens directly inhibit atherosclerotic lesion formation although the underlying mechanisms for this remain unclear. This study addressed the hypothesis that endogenous androgens inhibit arterial remodelling by a direct action on the androgen receptor (AR) in the vascular wall.

Methods and results

We studied a series of novel mouse lines with cell-specific deletion of the AR in either the endothelium or in smooth muscle cells or both cell types. Findings were compared with a model of global androgen deficiency in wild-type mice (castrated). We characterized the cardiovascular phenotype, vascular pharmacology and histology, and assessed neointimal lesion formation following vascular injury to the femoral artery. Cell-specific AR deletion did not alter body weight, circulating testosterone levels or seminal vesicle weight, but caused limited alterations in arterial contractility and blood pressure. Neointimal lesion formation was unaltered by selective deletion of AR from the vascular endothelium, smooth muscle, or both cell types. Castration in wild-type mice increased neointimal lesion volume (Sham vs. Castration: 2.4 × 10⁷ ± 4.5 × 10⁶ vs. 3.9 × 10⁷ ± 4.9 × 10⁶ µm³, P = 0.04, n = 9–10).

Conclusion

Vascular cell-specific AR deletion had no effect on neointimal lesion formation, while low systemic androgen levels adversely affect neointimal lesion size. These findings suggest that the cardio-protective effects of androgens are mediated either by AR outside the vasculature or by AR-independent mechanisms.

Testosterone enhances functional recovery after stroke through promotion of antioxidant defenses, BDNF levels and neurogenesis in male rats

It is reported that circulating testosterone levels decrease after cerebral ischemia. The aim of this study was to evaluate the effects of testosterone on oxidative stress, brain-derived neurotrophic factor (BDNF) levels, neurogenesis, histological damage and sensorimotor recovery in a castrated male rat model of focal cerebral ischemia. Animals were divided into four groups. For all animals, castrations were conducted 7 days before transient middle cerebral artery occlusion (MCAO) was done and cerebral ischemia was induced. The first group served as sham. Second was MCAO group and received vehicle only, third was MCAO group that was post-treated with testosterone and the fourth was MCAO group post-treated with testosterone and flutamide. Treatment only with testosterone significantly weakened oxidative stress and increased BDNF levels and sensorimotor recovery during a 10 days period. Rats receiving testosterone demonstrated a significant reduction in infarct volume and a significant increase in neurogenesis on 10th day after focal cerebral ischemia. Our results for the first time showed a potential advantageous effect of testosterone after cerebral ischemia in male rats, which was probably mediated by promoting antioxidant defenses, BDNF levels and neurogenesis.

Role of androgens in sex differences in cardiac damage during myocardial infarction

Age-specific incidence of ischemic heart disease in men is higher than in women, although women die more frequently without previous symptoms; the molecular mechanism(s) are poorly understood. Most studies focus on protection by estrogen, with less attention on androgen receptor-mediated androgen actions. Our aim was to determine the role of androgens in the sex differences in cardiac damage during myocardial infarction. Mature age-matched male and female Sprague Dawley rats, intact or surgically gonadectomized (Gx), received testosterone (T) or 17β-estradiol (E2) via subdermal SILASTIC (Dow Corning Corp.) implants; a subset of male rats received dihydrotestosterone. After 21 days, animals were anesthetized, and hearts were excised and subjected to ex vivo regional ischemia-reperfusion (I-R). Hearts from intact males had larger infarcts than those from females following I-R; Gx produced the opposite effect, confirming a role for sex steroids. In Gx males, androgens (dihydrotestosterone, T) and E2 aggravated I-R-induced cardiac damage, whereas in Gx females, T had no effect and E2 reduced infarct area. Increased circulating T levels up-regulated androgen receptor and receptor for advanced glycation end products, which resulted in enhanced apoptosis aggravating cardiac damage in both males and females. In conclusion, our study demonstrates, for the first time, that sex steroids regulate autophagy during myocardial infarction and shows that a novel mechanism of action for androgens during I-R is down-regulation of antiapoptotic protein Bcl-xL (B cell lymphoma-extra large), a key controller for cross talk between autophagy and apoptosis, shifting the balance toward apoptosis and leading to aggravated cardiac damage.

Testosterone promotes vascular endothelial cell migration via upregulation of ROCK-2/moesin cascade

Cross-sectional studies have demonstrated a reverse relationship between serum level of testosterone (T) and the incidence rate of cardiovascular disease in men, indicating that T exerts beneficial effects in cardiovascular system. However, the endothelial effects of T are poorly understood. Actin remodeling is essential for endothelial cell movement and vascular repair and this process is controlled by the actin-binding protein moesin. In the present study, we studied the effects of T on actin remodeling, moesin expression and phosphorylation, as well as cell migration in cultured human umbilical endothelial cells (hUVECs). We found that T provoked the formation of cortical actin complexes and membrane protrusions in endothelial cells. Treatment with T induced dose- and time-dependent increase of moesin expression and phosphorylation, which was inhibited by the addition of androgen receptor antagonist hydroxyflutamide (HF). Moreover, T enhanced ROCK-2 activity. The ROCK-2 inhibitor Y27632 or the transfection of ROCK-2 siRNA largely inhibited T-induced moesin expression and phosphorylation, indicating that ROCK-2 pathway is crucial for these effects. T promoted endothelial cell migration, which was inhibited by the addition of HF or Y27632. In conclusion, T induces actin cytoskeleton remodeling by regulating moesin expression and activation, resulting in enhanced endothelial cell migration. Our work adds new insights into endothelial mechanisms of T, which is relevant for its vascular actions.

Endothelial cells overexpressing IL-8 receptor reduce cardiac remodeling and dysfunction following myocardial infarction

The endothelium is a dynamic component of the cardiovascular system that plays an important role in health and disease. This study tested the hypothesis that targeted delivery of endothelial cells (ECs) overexpressing neutrophil membrane IL-8 receptors IL8RA and IL8RB reduces acute myocardial infarction (MI)-induced left ventricular (LV) remodeling and dysfunction and increases neovascularization in the area at risk surrounding the infarcted tissue. MI was created by ligating the left anterior descending coronary artery in 12-wk-old male Sprague-Dawley rats. Four groups of rats were studied: group 1: sham-operated rats without MI or EC transfusion; group 2: MI rats with intravenous vehicle; group 3: MI rats with transfused ECs transduced with empty adenoviral vector (Null-EC); and group 4: MI rats with transfused ECs overexpressing IL8RA/RB (1.5 × 10⁶ cells post-MI). Two weeks after MI, LV function was assessed by echocardiography; infarct size was assessed by triphenyltetrazolium chloride (live tissue) and picrosirus red (collagen) staining, and capillary density and neutrophil infiltration in the area at risk were measured by CD31 and MPO immunohistochemical staining, respectively. When compared with the MI + vehicle and MI-Null-EC groups, transfusion of IL8RA/RB-ECs decreased neutrophil infiltration and pro-inflammatory cytokine expression and increased capillary density in the area at risk, decreased infarct size, and reduced MI-induced LV dysfunction. These findings provide proof of principle that targeted delivery of ECs is effective in repairing injured cardiac tissue. Targeted delivery of ECs to infarcted hearts provides a potential novel strategy for the treatment of acute MI in humans.

Hypoxia-inducible factor-1α(Pro-582-Ser) polymorphism prevents iron deprivation in healthy blood donors

BACKGROUND

Frequent blood loss induces progressive depletion of iron stores, leading to iron deficiency and, ultimately, to overt iron-deficient anaemia. The erythropoietin-mediated bone marrow response to anaemia is under the control of hypoxia-inducible factors (HIF), the master regulators of oxygen and iron homeostasis. Since the HIF-1α(Pro-582-Ser) variant is associated with elevated trans-activation capacity of hypoxia responsive elements of target genes, we investigated whether the HIF-1α(Pro-582-Ser) polymorphism might influence the response to repeated blood withdrawals.

MATERIALS AND METHODS

Using polymerase chain reaction analysis and DNA sequencing, we retrospectively investigated the presence of HIF-1α(Pro-582-Ser) in a series of 163 blood donors. Haematological findings, serum ferritin levels and frequency of donations were compared according to the mutational status of the HIF-1α gene.

RESULTS

We found that male carriers of the HIF-1α(Pro-582-Ser) polymorphism had higher haemoglobin and ferritin levels than individuals homozygous for the wild-type allele. Moreover, the HIF-1α(Pro-582-Ser) polymorphism protected regular blood donors from developing iron deficiency and anaemia and predicted uninterrupted donation activity.

DISCUSSION

These findings show for the first time that the HIF-1α(Pro-582-Ser) polymorphism significantly affects red blood cell and iron homeostasis after blood loss, conferring to male carriers a resistance to anaemia. Regarding the female gender, large series of individuals should be investigated to establish whether there is an effect of the HIF-1α(Pro-582-Ser) polymorphism in this population. Although these data need to be confirmed in prospective studies, they could have important implications in blood donor selection and donation procedures.

Impact of the hypoxia-inducible factor-1 α (HIF1A) Pro582Ser polymorphism on diabetes nephropathy

OBJECTIVE

Hypoxia plays a major pathogenic role in diabetic nephropathy (DN). We have investigated in this study the effect of hypoxia-inducible factor 1 α subunit (HIF1A) genetic polymorphisms on the development of DN.

RESEARCH DESIGN AND METHODS

In 1,165 American type 1 diabetic patients with and without DN selected from the Genetics of Kidneys in Diabetes (GoKinD) study, the HIF1A genetic polymorphisms were genotyped with TaqMan allelic discrimination. The regulation of HIF-1α in the kidneys of diabetic mice was appreciated by immunohistochemistry, and the effect HIF1A Pro582Ser polymorphism on HIF-1α sensitivity to glucose was evaluated in vitro.

RESULTS

We identified a protective association between HIF1A Pro582Ser polymorphism and DN in male subjects. We also provided mechanistic insights that HIF-1α is repressed in the medulla of diabetic mice despite hypoxia and that Pro582Ser polymorphism confers less sensitivity to the inhibitory effect of glucose during a hypoxic challenge.

CONCLUSIONS

The current study demonstrates for the first time that HIF1A Pro582Ser polymorphism has an effect on DN, possibly by conferring a relative resistance to the repressive effect of glucose on HIF-1α.