Testosterone-down-regulated Akt pathway during cardiac ischemia/reperfusion: a mechanism involving BAD, Bcl-2 and FOXO3a

Influence of Sex in the Development of Liver Diseases

The liver is a sexually dimorphic organ. Sex differences in prevalence, progression, prognosis, and treatment prevail in most liver diseases, and the mechanism of how liver diseases act differently among male versus female patients has not been fully elucidated. Biological sex differences in normal physiology and disease arise principally from sex hormones and/or sex chromosomes. Sex hormones contribute to the development and progression of most liver diseases, with estrogen- and androgen-mediated signaling pathways mechanistically involved. In addition, genetic factors in sex chromosomes have recently been found to contribute to the sex disparity of many liver diseases, which might explain, to some extent, the difference in gene expression pattern, immune response, and xenobiotic metabolism between men and women. Although increasing evidence suggests that sex is one of the most important modulators of disease prevalence and outcomes, at present, basic and clinical studies have long been sex unbalanced, with female subjects underestimated. As such, this review focuses on sex disparities of liver diseases and summarizes the current understanding of sex-specific mechanisms, including sex hormones, sex chromosomes, etc. We anticipate that understanding sex-specific pathogenesis will aid in promoting personalized therapies for liver disease among male versus female patients.

Understanding the Role of Sex Hormones in Cardiovascular Kidney Metabolic Syndrome: Toward Personalized Therapeutic Approaches

Cardiovascular kidney metabolic (CKM) syndrome represents a complex interplay of cardiovascular disease (CVD), chronic kidney disease (CKD), and metabolic comorbidities, posing a significant public health challenge. Gender exerts a critical influence on CKM syndrome, affecting the disease severity and onset through intricate interactions involving sex hormones and key physiological pathways such as the renin-angiotensin system, oxidative stress, inflammation, vascular disease and insulin resistance. It is widely known that beyond the contribution of traditional risk factors, men and women exhibit significant differences in CKM syndrome and its components, with distinct patterns observed in premenopausal women and postmenopausal women compared to men. Despite women generally experiencing a lower incidence of CVD, their outcomes following cardiovascular events are often worse compared to men. The disparities also extend to the treatment approaches for kidney failure, with a higher prevalence of dialysis among men despite women exhibiting higher rates of CKD. The impact of endogenous sex hormones, the correlations between CKM and its components, as well as the long-term effects of treatment modalities using sex hormones, including hormone replacement therapies and gender-affirming therapies, have drawn attention to this topic. Current research on CKM syndrome is hindered by the scarcity of large-scale studies and insufficient integration of gender-specific considerations into treatment strategies. The underlying mechanisms driving the gender disparities in the pathogenesis of CKM syndrome, including the roles of estrogen, progesterone and testosterone derivatives, remain poorly understood, thus limiting their application in personalized therapeutic interventions. This review synthesizes existing knowledge to clarify the intricate relationship between sex hormones, gender disparities, and the progression of CVD within CKM syndrome. By addressing these knowledge gaps, this study aims to guide future research efforts and promote tailored approaches for effectively managing CKD syndrome.

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.

Optimisation of hormonal treatment to improve follicular development in one-day-old mice ovaries cultured under in vitro condition

CONTEXT

Base medium containing knock-out serum replacement (KSR) has been found to support formation and maintenance of follicles in one-day-old mice ovaries, but has not been shown to properly support activation and growth of primordial follicles.

AIMS

The present study was conducted to tailor the hormonal content of base medium containing KSR to enhance development of primordial follicles in neonatal ovaries.

METHODS

One-day-old mice ovaries were initially cultured with base medium for four days, and then, different hormonal treatments were added to the culture media and the culture was proceeded for four additional days until day eight. Ovaries were collected for histological and molecular assessments on days four and eight.

KEY RESULTS

In experiment I, the main and interactive effects of FSH and testosterone were investigated and FSH promoted activation of primordial follicles and development of primary and preantral follicles, and upregulated genes of phosphoinositide 3-kinase (Pi3k ), KIT ligand (Kitl ), growth differentiation factor 9 (Gdf9 ) and follicle stimulating hormone receptor (Fshr ) (P Bmp15 ), Connexin-43 (Cx43 ) and luteinising hormone and choriogonadotropin receptor (Lhcgr ) (P P Lhcgr (P P >0.05).

CONCLUSIONS

Supplementation of culture medium containing KSR with gonadotropins, particularly hMG, could improve follicular growth and expression of factors regulating follicular development.

IMPLICATIONS

This study was a step forward in formulating an optimal medium for development of follicles in cultured one-day-old mice ovaries.

Reduced expression of phosphorylated ataxia-telangiectasia mutated gene is related to poor prognosis and gemcitabine chemoresistance in pancreatic cancer

BACKGROUND

Loss of expression of the gene ataxia-telangiectasia mutated (ATM), occurring in patients with multiple primary malignancies, including pancreatic cancer, is associated with poor prognosis. In this study, we investigated the detailed molecular mechanism through which ATM expression affects the prognosis of patients with pancreatic cancer.

METHODS

The levels of expression of ATM and phosphorylated ATM in patients with pancreatic cancer who had undergone surgical resection were analyzed using immunohistochemistry staining. RNA sequencing was performed on ATM-knockdown pancreatic-cancer cells to elucidate the mechanism underlying the invlovement of ATM in pancreatic cancer.

RESULTS

Immunohistochemical analysis showed that 15.3% and 27.8% of clinical samples had low levels of ATM and phosphorylated ATM, respectively. Low expression of phosphorylated ATM substantially reduced overall and disease-free survival in patients with pancreatic cancer. In the pancreatic cancer cell lines with ATM low expression, resistance to gemcitabine was demonstrated. The RNA sequence demonstrated that ATM knockdown induced the expression of MET and NTN1. In ATM knockdown cells, it was also revealed that the protein expression levels of HIF-1α and antiapoptotic BCL-2/BAD were upregulated.

CONCLUSIONS

These findings demonstrate that loss of ATM expression increases tumor development, suppresses apoptosis, and reduces gemcitabine sensitivity. Additionally, loss of phosphorylated ATM is associated with a poor prognosis in patients with pancreatic cancer. Thus, phosphorylated ATM could be a possible target for pancreatic cancer treatment as well as a molecular marker to track patient prognosis.

Sex differences in hepatic ischemia‒reperfusion injury: a cross-sectional study

Several studies have shown that males suffer more severe damage than females in the process of ischemia and reperfusion of the brain, heart and kidney. Accordingly, our study will reveal the correlation between the severity of hepatic ischemia‒reperfusion injury (HIRI) and sex, and preliminarily analyze the underlying mechanism. A total of 75 patients who were considered to have "benign liver tumors" at the initial admission and underwent partial hepatectomy were enrolled. We identified potential differences between different groups and discussed the correlation between the severity of HIRI and sex through a comparative analysis. Results showed that HIRI was more severe in males than in females, especially in younger patients. To explore whether estrogen level differences are the main reason for the sex differences in HIRI, we further revealed that HIRI in premenopausal females was more severe than that in postmenopausal females. By comparing the levels of gonadal hormones, we speculated that multiple gonadal hormones, including follicle-stimulating hormone, luteinizing hormone and testosterone, may jointly participate in the regulation of sex differences in HIRI together with estrogen.

The forkhead box O3 (FOXO3): a key player in the regulation of ischemia and reperfusion injury

Forkhead box O3 is a protein encoded by the FOXO3 gene expressed throughout the body. FOXO3 could play a crucial role in longevity and many other pathologies, such as Alzheimer's disease, glioblastoma, and stroke. This study is a comprehensive review of the expression of FOXO3 under ischemia and reperfusion (IR) and the molecular mechanisms of its regulation and function. We found that the expression level of FOXO3 under ischemia and IR is tissue-specific. Specifically, the expression level of FOXO3 is increased in the lung and intestinal epithelial cells after IR. However, FOXO3 is downregulated in the kidney after IR and in the skeletal muscles following ischemia. Interestingly, both increased and decreased FOXO3 expression have been reported in the brain, liver, and heart following IR. Nevertheless, these contribute to stimulating ischemia and reperfusion injury via the induction of inflammatory response, apoptosis, autophagy, mitophagy, pyroptosis, and oxidative damage. These results suggest that FOXO3 could play protective effects in some organs and detrimental effects in others against IR injury. Most importantly, these findings indicate that controlling FOXO3 expression, genetically or pharmacologically, could contribute to preventing or treating ischemia and reperfusion damage.

VSIG4 regulates macrophages polarization and alleviates inflammation through activating PI3K/AKT and inhibiting TLR4/NF-κB pathway in myocardial ischemia-reperfusion injury rats

Background

Myocardial infarction is the primary cause of high disability and mortality in patients with cardiovascular disease worldwide. The pathological process of myocardial ischemia/reperfusion (I/R) may trigger harmful inflammatory response and ultimately lead to serious cardiac dysfunction. The mechanism of myocardial repair post myocardial infarction has not been fully elucidated. The present study speculated that VSIG4 is related to the regulation of heart injury.

Methods

The myocardial I/R injury model was established in Sprague-Dawley (SD) rats. Before I/R operation, the viral solution containing AAV-NC or AAV-VSIG4 was intravenously injected into rats. Cardiac function indicators, mRNA expression, the apoptosis ratio of cardiomyocytes, myocardial infarct area, phenotype polarization of macrophage, and the protein expression of apoptosis or macrophage phenotype were measured.

Results

Myocardial I/R injury decreased the expression of VSIG4 and subsequently triggered myocardial apoptosis. The induction of AAV-VSIG4 produced a protective effect on general cardiac function and attenuated the I/R-induced cellular apoptosis in rats. Moreover, VSIG4 signaling might potentially modulate macrophage M1/M2-related inflammatory disorders via activation of PI3K/AKT and inhibition of TLR4/NF-κB expression.

Conclusion

In summary, the present study provided evidence that VSIG4 had cardiac protective role in myocardial I/R injury. More importantly, enhanced VSIG4 expression inhibited M1 polarization of macrophages by blocking TLR4/NF-κB activation, subsequently suppressing cardiomyocyte apoptosis. This finding provides vital insights into the role of VSIG4 in I/R injury and may provide a new target for I/R therapy.

Novel prevention insights into depletion of oxidative stress status through regular exercise and grape seed effective substance in heart ischemia rat model

Myocardial ischemia (MI) is recognized as the most frequent cardiovascular disease which is the dominant cause of global morbidity and mortality. Artificial intelligence tools and integrative data analysis revealed superoxide dismutase, catalase, glutathione peroxidase, gap junction protein α, myosin heavy chains, and zinc finger transcription factor GATA4 are engaged in oxidative stress and in cardiomyopathy. Network analysis indicated that MAPK3 might be the highest distribution property and cut point in this network, which could be a potential candidate for preventing and treating oxidative stress in heart tissue. Among antioxidant agents, grape seed extract (GSE) is an effective substance that altered antioxidant status in heart tissue. Considering drug discovery methods, we illustrated that GSE might target the MAPK3 protein with sufficient binding affinity. Moreover, we found that low- and moderate-intensity training might prevent the depletion of antioxidants after MI. GSE consumption altered the levels of superoxide dismutase, glutathione peroxidase, and catalase after 14 weeks. Therefore, the interaction of low- and moderate-intensity training and GSE had a synergistic effect on the antioxidant status and relative expression of the Mapk3. Moreover, the interaction of high-intensity training and GSE had a compensatory mechanism that could scavenge reactive oxygen species and improve endogenous antioxidants and modulate the Mapk3 level in MI rats. Consequently, we displayed positive influence and synergic effects of simultaneous GSE prescription and regular physical activity for 14 weeks to prevent acute and chronic heart ischemia cardioprotective phenomenon. Furthermore, the capacitation oxidative stress and relative expression of the Mapk3 was significantly increased by GSE and regular exercise.

Aquaporin 4 in Traumatic Brain Injury: From Molecular Pathways to Therapeutic Target

Traumatic brain injury (TBI) is known as an acute degenerative pathology of the central nervous system, and has been shown to increase brain aquaporin 4 (AQP4) expression. Various molecular mechanisms affect AQP4 expression, including neuronal high mobility group box 1, forkhead box O3a, vascular endothelial growth factor, hypoxia-inducible factor-1 α (HIF-1 α) sirtuin 2, NF-κB, Malat1, nerve growth factor and Angiotensin II receptor type 1. In addition, inhibition of AQP4 with FK-506, MK-801 (indirectly by targeting N-methyl-D-aspartate receptor), inactivation of adenosine A2A receptor, levetiracetam, adjudin, progesterone, estrogen, V1aR inhibitor, hypertonic saline, erythropoietin, poloxamer 188, brilliant blue G, HIF-1alpha inhibitor, normobaric oxygen therapy, astaxanthin, epigallocatechin-3-gallate, sesamin, thaliporphine, magnesium, prebiotic fiber, resveratrol and omega-3, as well as AQP4 gene silencing lead to reduced edema upon TBI. This review summarizes current knowledge and evidence on the relationship between AQP4 and TBI, and the potential mechanisms involved.

Combined genetic and chemical screens indicate protective potential for EGFR inhibition to cardiomyocytes under hypoxia

The return of blood flow to ischemic heart after myocardial infarction causes ischemia-reperfusion injury. There is a clinical need for novel therapeutic targets to treat myocardial ischemia-reperfusion injury. Here we screened for targets for the treatment of ischemia-reperfusion injury using a combination of shRNA and drug library analyses in HL-1 mouse cardiomyocytes subjected to hypoxia and reoxygenation. The shRNA library included lentiviral constructs targeting 4625 genes and the drug library 689 chemical compounds approved by the Food and Drug Administration (FDA). Data were analyzed using protein-protein interaction and pathway analyses. EGFR inhibition was identified as a cardioprotective mechanism in both approaches. Inhibition of EGFR kinase activity with gefitinib improved cardiomyocyte viability in vitro. In addition, gefitinib preserved cardiac contractility in zebrafish embryos exposed to hypoxia-reoxygenation in vivo. These findings indicate that the EGFR inhibitor gefitinib is a potential candidate for further studies of repurposing the drug for the treatment of myocardial infarction.

Sex-related differences in ventricular remodeling after myocardial infarction

The epidemiology, clinical features and outcome of myocardial infarction (MI) display significant differences between men and women. Prominent sex differences have also been suggested in left ventricular (LV) remodeling after MI. Ventricular remodeling refers to a deterioration of LV geometry and function often leading to heart failure (HF) development and an increased risk of adverse cardiovascular events. Women have a lower propensity to the acquisition of a spherical geometry and LV dysfunction. These differences can be attributed at least partially to a lower frequency of transmural infarction and smaller areas of microvascular obstruction in women, as well as to a less prominent activation of neuroendocrine systems and apoptotic, inflammatory and profibrotic pathways in women. Estrogens might play a role in this difference, which could partially persist even after the menopause because of a persisting intramyocardial synthesis of estrogens in women. Conversely, androgens may exert a detrimental influence. Future studies should better clarify sex differences in the predictors, clinical correlates, prognostic impact and disease mechanisms of remodeling, as well as the existence of sex-specific therapeutic targets. This research effort should hopefully allow to optimize the treatment of MI during the acute and post-acute phase, possibly through different therapeutic strategies in men and women, with the goal of reducing the risk of HF development and improving patient outcome.

An inquest into regulatory mechanism of caveolin by ischemic preconditioning against orchidectomy-challenged rat heart

Lower level of testosterone in men is related to major risks of cardiovascular diseases. This risk may increase due to the opening of mitochondrial permeability transition pore (mPTP). The mPTP is also regulated by ischemic preconditioning (IPC) and a membrane protein known as caveolin. The cardioprotective effect of IPC is the most effective methodologies used in testosterone deficiency. Daidzein (DDZ) a caveolin inhibitor shows cardioprotective action. The experiment has been designed to evaluate the pretreated DDZ effect in IPC-mediated cardioprotective action in orchidectomy (OCZ)-challenged rat heart. The experiment was designed on male Wistar rats with/without OCZ. The level of testosterone is decreased by OCZ which reduces general body growth. Isolated heart from normal and OCZ rat was tied up on Langendorff's perfused apparatus and followed by ischemic reperfusion (IR) and IPC cycle. To investigate the cardioprotective effect of DDZ in heart with testosterone deficiency, a total of nine groups, each consisting of six rats (n = 6) were as follows: Sham, IR, IPC, IPC + OCZ, IPC + DDZ, IPC + OCZ + DDZ, IPC + sodium nitrite, IPC + OCZ + sodium nitrite, IPC + OCZ + DDZ + sodium nitrite. Hemodynamic parameters, cellular injury (infarct size, LDH, CKMB and cardiac troponin-T), oxidative stress, mitochondrial function, integrity and immunoblot analysis were assessed for each group. The experimental data showed that DDZ potentiated IPC-mediated increase in the heart rate, left ventricular diastolic pressure, coronary flow; + dp/dt_max, and - dp/dt_max. The pretreated DDZ decreases the action of LDH and CKMB, myocyte size, cardiac collagen content, infarct size and ventricular fibrillation and attenuation in oxidative stress and mitochondrial dysfunction in OCZ-challenged rat heart in all sets of experiments. Sodium nitrite, a producer of nitric oxide (NO), enhanced potentiating effects of DDZ on IPC-mediated cardioprotection in OCZ-challenged rats. These observations show that the downregulation of caveolin through impaired opening of mPTP during reperfusion and caveolin might be a potential adjuvant to IPC against cardiac injury in OCZ-challenged rats.

Berry-Derived Polyphenols in Cardiovascular Pathologies: Mechanisms of Disease and the Role of Diet and Sex

Cardiovascular disease (CVD) prevalence, pathogenesis, and manifestation is differentially influenced by biological sex. Berry polyphenols target several signaling pathways pertinent to CVD development, including inflammation, oxidative stress, and cardiac and vascular remodeling, and there are innate differences in these pathways that also vary by sex. There is limited research systematically investigating sex differences in berry polyphenol effects on these pathways, but there are fundamental findings at this time that suggest a sex-specific effect. This review will detail mechanisms within these pathological pathways, how they differ by sex, and how they may be individually targeted by berry polyphenols in a sex-specific manner. Because of the substantial polyphenolic profile of berries, berry consumption represents a promising interventional tool in the treatment and prevention of CVD in both sexes, but the mechanisms in which they function within each sex may vary.

Anabolic steroid excess and myocardial infarction: From ischemia to reperfusion injury

Anabolic steroids (AS) are synthetic testosterone-derivatives developed by the pharmaceutical industry to mimic testosterone biological effects. So far, AS have been implicated in the treatment of pathological conditions, such as hypogonadism, anemia, and cachexia. Since their discovery, though, AS have been illicitly used by elite and recreational athletes, bodybuilders and weightlifters in order to enhance athletic and aesthetic performance. This practice is characterized by cycles of administration and withdrawal, the combination of different AS compounds, and administration of doses 50 - 1000 times higher than those recommended for therapeutic purposes. AS excess has been correlated to cardiovascular detrimental effects, including cardiac hypertrophy, arrhythmias, and hypertension. Particularly, acute myocardial infarction (AMI) has been extensively reported by clinical and post-mortem studies. Atherosclerosis, hypercoagulability state, increased thrombogenesis and vasospasm have arisen as potential causes of myocardial ischemia in AS users. Additionally, several experimental reports have demonstrated that AS can increase the susceptibility to cardiac ischemia/reperfusion injury, whereas the cardioprotection elicited by physical exercise and ischemic postconditioning is blunted. Altogether, these factors can contribute to increased AMI morbidity and mortality during AS excess, particularly when AS are combined with other compounds, such as thyroid hormones, growth hormones, insulin, and diuretics.

Ischemia and reperfusion injury following cardioplegic arrest is attenuated by age and testosterone deficiency in male but not female mice

BACKGROUND

Cardiovascular disease increases with age in both sexes. Treatment can require cardiac surgery, where the hearts are pre-treated with protective cardioplegic solution before ischemia and reperfusion (I/R). While endogenous estrogen is beneficial in I/R, whether testosterone is involved is uncertain and whether age modifies responses to I/R is unclear. We investigated sex- and age-specific differences in I/R injury in the hearts pre-treated with clinically relevant cardioplegic solution.

METHODS

The hearts were isolated from young (6-9 months) and old (20-28 months) mice of both sexes and perfused (Langendorff) with Krebs-Henseleit buffer (15 min, 37 °C), followed by St. Thomas' two cardioplegia (6 min, 6-7 °C), global ischemia (90 min, 23-24 °C), and reperfusion (30 min, 37 °C). The hearts were perfused with triphenyltetrazolium chloride to quantify infarct area. Testosterone's role was investigated in gonadectomized (GDX, 6-9 months) male mice; serum testosterone and estradiol were measured with ELISA assays.

RESULTS

Left ventricular developed pressure (LVDP) recovered to 67.3 ± 7.4% in the old compared to 21.8 ± 9.2% in the young male hearts (p < 0.05). Similar results were seen for rates of pressure development (+dP/dt) and decay (-dP/dt). Infarct areas were smaller in the old male hearts (16.6 ± 1.6%) than in the younger hearts (55.8 ± 1.2%, p < 0.05). By contrast, the hearts from young and old females exhibited a similar post-ischemic functional recovery and no age-dependent difference in infarcts. There was a sex difference in the young group, where ventricular function (LVDP, +dP/dt, -dP/dt) recovered better and infarcts were smaller in females than males. Estradiol levels were highest in young females. Testosterone was high in young males but low in females and old males, which suggested beneficial effects of low testosterone. Indeed, the hearts from GDX males exhibited much better recovery of LVDP in reperfusion than that from intact males (values were 64.4 ± 7.5 % vs. 21.8 ± 9.2%; p < 0.05). The GDX hearts also had smaller infarcts than the hearts from intact males (p < 0.05).

CONCLUSIONS

Although age had no effect on susceptibility to I/R injury after cardioplegic arrest in females, it actually protected against injury in older males. Our findings indicate that low testosterone may be protective against I/R injury following cardioplegic arrest in older males.

Calcification Induced by Type I Interferon in Human Aortic Valve Interstitial Cells Is Larger in Males and Blunted by a Janus Kinase Inhibitor

Objective- Calcific aortic valve disease is the most prevalent valvulopathy in Western countries. An unanticipated pathogenetic clue involving IFN (interferon) was disclosed by the finding of constitutive type I IFN activity associated with aortic valve calcification in children with the atypical Singleton-Merten syndrome. On this basis, the role of type I IFN on inflammation and calcification in human aortic valve interstitial cells (AVIC) was examined. Approach and Results- IFN-α was weakly proinflammatory but potentiated lipopolysaccharide-mediated activation of NF (nuclear factor)-κB and the ensuing induction of proinflammatory molecules in human AVIC. Stimulation with IFN-α and in combination with lipopolysaccharide promoted osteoblast-like differentiation characterized by increased osteoblastic gene expression, BMP (bone morphogenetic protein)-2 secretion, and ectopic phosphatase activity. Sex differences were observed. Likewise, IFN-α treatment of human AVICs in osteogenic medium resulted in increased formation of calcific nodules. Strikingly, IFN-α-mediated calcification was significantly higher in AVICs from males, and was blocked by tofacitinib, a JAK (Janus kinase) inhibitor, and by a BMP antagonist. A female-specific protective mechanism involving the activation of PI3K-Akt (protein kinase B) pathways and cell survival was disclosed. Females exhibited higher levels of BCL2 in valve cells and tissues and lower annexin V staining on cell stimulation. Conclusions- IFN-α acts as a proinflammatory and pro-osteogenic cytokine in AVICs, its effects being potentiated by lipopolysaccharide. Results also uncovered sex differences with lower responses in female AVICs and sex-specific mechanisms involving apoptosis. Data point to JAK/STAT (signal transducer and activator of transcription) system as a potential therapeutic target for calcific aortic valve disease.

Paradoxical effect of testosterone supplementation therapy on cardiac ischemia/reperfusion injury in aged rats

Aging is followed by numerous physiological limitations that reduce health span, particularly cardiovascular and metabolic disorders. Testosterone supplementation therapy (TST) has been widely used in the treatment of aging dysfunctions in either adult or aged patients, although recent evidence have suggested that the incidence of myocardial infarction might be increased in elderly patients. So far, though, the effects of TST in the progression of cardiac ischemia/reperfusion (IR) injury in aged hearts remain unclear. Male aged (23-24 months old) and adult (6 months old) Wistar rats were treated with placebo (Old + Placebo n = 5 / Adult + Placebo n = 5) or TST (Old + TST n = 7 / Adult + TST n = 5) for 30 days. After euthanasia, artificially-perfused isolated rat hearts were submitted to IR. Cardiac expression levels of genes encoding α and β myosin heavy chain (MHC), ryanodine receptor (RyR), brain-natriuretic peptide (BNP), sarcoplasmic reticulum Ca2+ ATPase 2a (SERCA2a), glucose-regulated protein 78 kDa (GRP78), eukaryotic initiation factor 2α (eIF2α), C/EBP-homologous protein (CHOP), caspase 3 and B cell lymphoma 2 (Bcl-2) were accessed by qRT-PCR. Protein levels of CHOP, p-Akt, and p-glycogen synthase kinase 3β (p-GSK-3β) were measured by Western Blot. Compared to placebo-treated aged rats, Old + TST group exhibited increased heart weight and up-regulation of αMHC mRNA expression levels, whereas βMHC mRNA expression (p < 0.05). During reperfusion, left ventricular developed pressure, dP/dt+, dP/dt-, and cardiac contractile function index were increased in Old + TST rat hearts (p < 0.05), whereas infarct size was increased (p < 0.05) in comparison with Old + Placebo group. p-Akt levels of Old + TST rat hearts were decreased when compared to Old + Placebo group. Conversely, TST did not promote significant effects in adult rat hearts. Taken together, these findings suggest that myocardial stunning and infarct size of aged hearts were distinctly affected by TST.

Dihydromyricetin protects HUVECs of oxidative damage induced by sodium nitroprusside through activating PI3K/Akt/FoxO3a signalling pathway

The damage of vascular endothelial cells induced by oxidative stress plays an important role in the pathogenesis of atherosclerosis. Dihydromyricetin (DMY) is considered as a natural antioxidant. However, the mechanism of DMY on endothelial cell injury induced by oxidative stress remains unclear. In this study, we found that DMY could reduce the oxidative damage of HUVECs induced by sodium nitroprusside (SNP), HUVECs pre-treated with DMY suppressed SNP-induced apoptosis by reduced ROS overproduction of intracellular, decreased MDA level and elevated the superoxide dismutase activity. Meanwhile, we found that DMY could promote the expression of phosphorylated FoxO3a and Akt, and affect the nuclear localization of FoxO3a, when treated with the PI3K inhibitor LY294002, the effect of DMY was blocked. These data suggest that DMY protects HUVECs from oxidative stress by activating PI3K/Akt/FoxO3a signalling pathway. Therefore, DMY may have great therapeutic potential as a new drug for atherosclerosis.

Role of Gender in Regulation of Redox Homeostasis in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is one of the diseases with a well-established gender dimorphism. The prevalence of PAH is increased in females with a ratio of 4:1, while poor survival prognosis is associated with the male gender. Nevertheless, the specific contribution of gender in disease development and progression is unclear due to the complex nature of the PAH. Oxidative and nitrosative stresses are important contributors in PAH pathogenesis; however, the role of gender in redox homeostasis has been understudied. This review is aimed to overview the possible sex-specific mechanisms responsible for the regulation of the balance between oxidants and antioxidants in relation to PAH pathobiology.

Sex Differences in Autophagy Contribute to Female Vulnerability in Alzheimer's Disease

Alzheimer's disease (AD) is the most common form of dementia, with over 5. 4 million cases in the US alone (Alzheimer's Association, 2016). Clinically, AD is defined by the presence of plaques composed of Aβ and neurofibrillary pathology composed of the microtubule associated protein tau. Another key feature is the dysregulation of autophagy at key steps in the pathway. In AD, disrupted autophagy contributes to disease progression through the failure to clear pathological protein aggregates, insulin resistance, and its role in the synthesis of Aβ. Like many psychiatric and neurodegenerative diseases, the risk of developing AD, and disease course are dependent on the sex of the patient. One potential mechanism through which these differences occur, is the effects of sex hormones on autophagy. In women, the loss of hormones with menopause presents both a risk factor for developing AD, and an obvious example of where sex differences in AD can stem from. However, because AD pathology can begin decades before menopause, this does not provide the full answer. We propose that sex-based differences in autophagy regulation during the lifespan contribute to the increased risk of AD, and greater severity of pathology seen in women.

The role of microRNA-1 targeting of MAPK3 in myocardial ischemia-reperfusion injury in rats undergoing sevoflurane preconditioning via the PI3K/Akt pathway

Recent studies have uncovered the vital roles played by microRNAs in regulating cardiac injury. Among them, the cardiac enriched microRNA-1 (miR-1) has been extensively studied and proven to be detrimental to cardiac myocytes. Hence, the current study aimed to explore whether miR-1 affects myocardial ischemia-reperfusion injury (MIRI) in rats undergoing sevoflurane preconditioning and the underlying mechanism. After successful model establishment, rats with MIRI were transfected with mimics or inhibitors of miR-1, or siRNA against MAPK3, and then were injected with sevoflurane. A luciferase reporter gene assay was conducted to evaluate the targeting relationship between miR-1 and MAPK3. Reverse transcription quantitative polymerase chain reaction and Western blot analysis were employed to evaluate the expressions of miR-1, MAPK3, phosphatidylinositol 3-kinase (PI3K), and Akt. Additionally, the concentration of lactate dehydrogenase (LDH) was determined. Cell apoptosis and viability were assessed using TUNEL and cell counting kit-8 assays, and the ischemic area at risk and infarct size were detected using Evans blue and triphenyltetrazolium chloride staining. MAPK3 was found to be the target gene of miR-1. miR-1 expressed at a high level whereas MAPK3 expressed at a low level in MIRI rats. Overexpressing miR-1 or silencing MAPK3 blocked the PI3K/Akt pathway to increase cell apoptosis, ischemic area at risk, and infarct area but decreased cell viability and increased LDH concentration. In contrast, miR-1 downregulation abrogated the effects induced by miR-1 mimics or siRNA against MAPK3. These findings indicate that inhibition of miR-1 promotes MAPK3 to protect against MIRI in rats undergoing sevoflurane preconditioning through activation of the PI3K/Akt pathway.

Dhcr24 activates the PI3K/Akt/HKII pathway and protects against dilated cardiomyopathy in mice

BACKGROUND

24-dehydrocholesterol reductase (Dhcr24) catalyzes the last step of cholesterol biosynthesis, which is required for normal development and anti-apoptotic activities of tissues. We found that Dhcr24 expression decreased in the cTnTR 141W dilated cardiomyopathy (DCM) transgenic mice. Therefore, we tested whether rescued expression of Dhcr24 could prevent the development of DCM and its possible mechanism.

METHODS

Heart tissue specific transgenic overexpression mice of Dhcr24 was generated, then was crossed to cTnTR 141W mouse to obtain the double transgenic mouse (DTG). The phenotypes were demonstrated by the survival, cardiac geometry and function analysis, as well as microstructural and ultrastructural observations based on echocardiography and histology examination. The pathway and apoptosis were analysed by western blotting and TUNEL assay in vivo and in vitro.

RESULTS

We find that Dhcr24 decreased in hearts tissues of cTnTR 141W and LMNAE 82K DCM mice. The transgenic overexpression of Dhcr24 significantly improves DCM phenotypes in cTnTR 141W mice, and activates PI3K/Akt/HKII pathway, followed by a reduction of the translocation of Bax and release of cytochrome c, caspase-9 and caspase-3 activation and myocyte apoptosis. Knockdown the expression of Dhcr24 reduces the activation of PI3K/Akt/HKII pathway and inhibition of the mitochondrial-dependent apoptosis. The anti-apoptotic effect of Dhcr24 could be completely removed by the inhibition of PI3K pathway and partly removed by the HKII inhibitor in H9c2 cell line.

CONCLUSION

Compensatory expression of Dhcr24 protect against DCM through activated PI3K/Akt/HKII pathway and reduce Bax translocation. This is the first investigation for the molecular mechanism of Dhcr24 participate in development of DCM.

Salidroside induces apoptosis in human ovarian cancer SKOV3 and A2780 cells through the p53 signaling pathway

Salidroside is one of the most potent compounds extracted from the plant Rhodiola rosea, and its cardiovascular protective effects have been studied extensively. However, the role of salidroside in human ovarian carcinoma remains unknown. The aim of the current study was to investigate the effects of salidroside on the proliferation and apoptosis of SKOV3 and A2780 cells using MTT assay and acridine orange/ethidium bromide staining. Salidroside activated caspase-3 and upregulated the levels of apoptosis-inducing factor, Bcl-2-associated X and Bcl-2-associated death promoter (Bad) proteins. Furthermore, salidroside downregulated the levels of Bcl-2, p-Bad and X-linked inhibitor of apoptosis proteins. Salidroside activated the caspase-dependent pathway in SKOV3 and A2780 cells, upregulating p53, p21^Cip1/Waf1 and p16^INK4a. These results suggest that the p53/p21^Cip1/Waf1/p16^INK4a pathway may serve a key function in salidroside-mediated effects on SKOV3 and A2780 cells. The current findings indicate that salidroside may be a promising novel drug candidate for ovarian cancer therapy.

GYY4137 protects against myocardial ischemia/reperfusion injury via activation of the PHLPP-1/Akt/Nrf2 signaling pathway in diabetic mice

BACKGROUND

This study explores the protective effects of a hydrogen sulfide donor, morpholin-4-ium 4-methoxyphenyl-morpholino-phosphinodithioate (GYY4137), in the hearts of diabetic mice that had been subjected to myocardial ischemia/reperfusion injury. Diabetes impairs the Akt pathway, in which the Akt protein is dephosphorylated and inactivated by PH domain leucine-rich repeat protein phosphatase-1 (PHLPP-1). However, the function of PHLPP-1 and molecular mechanism that underlies the cardiac protection exerted by GYY4137 remains unknown.

METHODS

Diabetic or nondiabetic mice were subjected to 45 min of coronary artery occlusion followed by 2 h of reperfusion. H9c2 cells were cultured with normal or high glucose and then subjected to 3 h of hypoxia followed by 6 h of reoxygenation. Pretreatment with GYY4137 was performed in a randomized manner before ischemia/reperfusion or hypoxia/reoxygenation. The infarct size, cardiomyocyte apoptosis, and oxidative stress were measured. Western blotting was conducted to elucidate the protective mechanism.

RESULTS

Diabetic mice or H9c2 cells exposed to high glucose displayed a larger infarct size, more severe cardiomyocyte apoptosis, lower cell viability, and increased oxidative stress, which were associated with increased levels of PHLPP-1 and reduced levels of p-Akt and nuclear factor-erythroid-2-related factor 2 (Nrf2) protein expression. These changes were prevented/reversed by GYYG4137 pretreatment. At the cellular level, PHLPP-1 siRNA attenuated cellular injury, and this was associated with increased p-Akt and nuclear Nrf2 protein, whereas the decrement of Akt phosphorylation induced by LY294002 augmented cellular injury and decreased nuclear Nrf2.

CONCLUSIONS

GYY4137 activates the PHLPP-1/Akt/Nrf2 pathway to protect against diabetic myocardial ischemia/reperfusion injury.

THE PROTECTIVE ROLE OF ESTRADIOL & PROGESTERONE IN MALE RATS, FOLLOWING GASTRIC ISCHEMIA-REPERFUSION

Background and Aim

Ischemia-reperfusion (I/R) injury frequently occurs in different situations. Female sex hormones have a protective function. The purpose of this study was to determine the function of female sexual hormones on the gastric damage induced by I/R in male rats.

Methods

Forty (40) Wistar rats were randomized into five groups: intact, ischemia- reperfusion (IR), IR + estradiol (1mg/kg), IR + progesterone (16 mg / kg) and IR + combination of estradiol (1mg / kg) and progesterone (16 mg/ kg). Before the onset of ischemia and before reperfusion all treatments were done by intraperitoneal (IP) injection. After animal anesthesia and laparotomy, celiac artery was occluded for 30 minutes and then circulation was established for 24 hours. Results expressed as mean ± SEM and P <0.05 were considered statistically significant.

Results

The Glutathione (GSH) concentration significantly decreased after induction of gastric IR (P<0.001). Estradiol (P<0.001) and combined estradiol and progesterone (P<0.001) significantly increased GSH levels. The myeloperoxidase (MPO) concentration significantly increased after induction of gastric IR (P<0.001). Different treatments significantly reduced MPO levels (P<0.001). The gastric acid concentration significantly increased after induction of gastric IR (P<0.001). Treatment with estradiol, progesterone (P<0.05) and combined estradiol and progesterone (P<0.01) significantly reduced gastric acid levels. Superoxide dismutase (SOD) concentration decreased after induction of gastric IR. The SOD levels were not significant.

Conclusion

These data suggested that female sexual steroids have a therapeutic effect on gastrointestinal ischemic disorders by reduction of MPO and gastric acid, and increasing gastric GSH & SOD levels following gastric IR.

Survival kinase-dependent pathways contribute to gender difference in the response to myocardial ischemia-reperfusion and ischemic post-conditioning

The response to ischemia/reperfusion and the effects of ischemic post-conditioning (IPC) are sex-dependent, but the mechanisms have not been clarified. Male (M) and female (F) rat hearts isolated and perfused using the Langendorff technique were subject to 30 min of global ischemia (GI) and 60 min reperfusion (R). In IPC hearts, three cycles of 30-sec GI/30-sec R were applied at the beginning of R. Infarct size and myocardial function were assessed. Superoxide production, antioxidant systems, and expressions of phosphorylated forms of serine/threonine kinase (Akt), glycogen synthase kinase 3β (GSK-3β), protein kinase C ε (PKCε), endothelial nitric oxide synthase (eNOS), and apoptosis were measured. In the basal state, superoxide production and apoptosis were lower, and antioxidant systems and phospho-kinase expressions were higher in F rather than in M hearts. After ischemia-reperfusion, infarct size was less in F hearts, and post-ischemic recovery of myocardial function was higher in F rather than in M hearts. Superoxide production, phospho-kinase activity, phospho-eNOS, and apoptosis increased in both sexes while antioxidants decreased in both sexes. After IPC, infarct size, superoxide production, and apoptosis decreased and phospho-eNOS increased in F and M hearts but phospho-kinase expressions and post-ischemic recovery of myocardial function improved only in M hearts. These results show that Akt/GSK-3β/PKCε/eNOS-dependent pathways-mediated superoxide production and apoptosis appear as important factors involved in the observed gender differences.

Mild hypothermia pretreatment protects against liver ischemia reperfusion injury via the PI3K/AKT/FOXO3a pathway

Mild hypothermia is known to protect against ischemia and reperfusion (IR) injury. The exact mechanisms of the protection are not fully understood. Forkhead box O3 (FOXO3a) has been defined as a critical mediator in cellular processes, including oxidative stress, apoptosis, inflammation, cell death and DNA repair; however, the protection function in mild hypothermia has not been reported previously. The current study was designed to investigate the function of phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/FOXO3a pathway in pretreatment with mild hypothermia during IR injury. Additionally, PI3K/AKT/FOXO3a signaling was inhibited using Ly294002 and the effect on the protective function of mild hypothermia pretreatment was evaluated. Furthermore, the apoptotic and inflammatory response induced by the IR injury was evaluated. Liver IR injury induced a significant increase in the level of apoptosis and inflammatory responses. However, pretreatment with mild hypothermia increased phospho (p)-AKT and p-FOXO3a following IR injury, and significantly reduced apoptosis and inflammatory cytokines release. However, inhibiting p-AKT and p-FOXO3a using Ly294002 suppressed the liver protection produced by mild hypothermia. In conclusion, these findings indicated that mild hypothermia pretreatment exhibited liver protective effects against IR injury associated with suppressing inflammatory cytokine release and apoptosis via the PI3K/AKT/FOXO3a pathway.

The influence of sex steroid hormones on the response to trauma and burn injury

Trauma and related sequelae result in disturbance of homeostatic mechanisms frequently leading to cellular dysfunction and ultimately organ and system failure. Regardless of the type and severity of injury, gender dimorphism in outcomes following trauma have been reported, with females having lower mortality than males, suggesting that sex steroid hormones (SSH) play an important role in the response of body systems to trauma. In addition, several clinical and experimental studies have demonstrated the effects of SSH on the clinical course and outcomes following injury. Animal studies have reported the ability of SSH to modulate immune, inflammatory, metabolic and organ responses following traumatic injury. This indicates that homeostatic mechanisms, via direct and indirect pathways, can be maintained by SSH at local and systemic levels and hence result in more favourable prognosis. Here, we discuss the role and mechanisms by which SSH modulates the response of the body to injury by maintaining various processes and organ functions. Such properties of sex hormones represent potential novel therapeutic strategies and further our understanding of current therapies used following injury such as oxandrolone in burn-injured patients.

Administration of anabolic steroid during adolescence induces long-term cardiac hypertrophy and increases susceptibility to ischemia/reperfusion injury in adult Wistar rats

Chronic administration of anabolic androgenic steroids (AAS) in adult rats results in cardiac hypertrophy and increased susceptibility to myocardial ischemia/reperfusion (IR) injury. Molecular analyses demonstrated that hyperactivation of type 1 angiotensin II (AT1) receptor mediates cardiac hypertrophy induced by AAS and also induces down-regulation of myocardial ATP-sensitive potassium channel (K_ATP), resulting in loss of exercise-induced cardioprotection. Exposure to AAS during adolescence promoted long-term cardiovascular dysfunctions, such as dysautonomia. We tested the hypothesis that chronic AAS exposure in the pre/pubertal phase increases the susceptibility to myocardial ischemia/reperfusion (IR) injury in adult rats. Male Wistar rats (26day old) were treated with vehicle (Control, n=12) or testosterone propionate (TP) (AAS, 5mgkg^-1 n=12) 5 times/week during 5 weeks. At the end of AAS exposure, rats underwent 23days of washout period and were submitted to euthanasia. Langendorff-perfused hearts were submitted to IR injury and evaluated for mechanical dysfunctions and infarct size. Molecular analysis was performed by mRNA levels of α-myosin heavy chain (MHC), βMHC and brain-derived natriuretic peptide (BNP), ryanodine receptor (RyR2) and sarcoplasmic reticulum calcium ATPase 2a (SERCA2a) by quantitative RT-PCR (qRT-PCR). The expression of AT1 receptor and K_ATP channel subunits (Kir6.1 and SURa) was analyzed by qRT-PCR and Western Blot. NADPH oxidase (Nox)-related reactive oxygen species generation was assessed by spectrofluorimetry. The expression of antioxidant enzymes was measured by qRT-PCR in order to address a potential role of redox unbalance. AAS exposure promoted long-term cardiac hypertrophy characterized by increased expression of βMHC and βMHC/αMHC ratio. Baseline derivative of pressure (dP/dt) was impaired by AAS exposure. Postischemic recovery of mechanical properties was impaired (decreased left ventricle [LV] developed pressure and maximal dP/dt; increased LV end-diastolic pressure and minimal dP/dt) and infarct size was larger in the AAS group. Catalase mRNA expression was significantly decreased in the AAS group. In conclusion, chronic administration of AAS during adolescence promoted long-term pathological cardiac hypertrophy and persistent increase in the susceptibility to myocardial IR injury possible due to disturbances on catalase expression.

Mechanistic Pathways of Sex Differences in Cardiovascular Disease

Major differences between men and women exist in epidemiology, manifestation, pathophysiology, treatment, and outcome of cardiovascular diseases (CVD), such as coronary artery disease, pressure overload, hypertension, cardiomyopathy, and heart failure. Corresponding sex differences have been studied in a number of animal models, and mechanistic investigations have been undertaken to analyze the observed sex differences. We summarize the biological mechanisms of sex differences in CVD focusing on three main areas, i.e., genetic mechanisms, epigenetic mechanisms, as well as sex hormones and their receptors. We discuss relevant subtypes of sex hormone receptors, as well as genomic and nongenomic, activational and organizational effects of sex hormones. We describe the interaction of sex hormones with intracellular signaling relevant for cardiovascular cells and the cardiovascular system. Sex, sex hormones, and their receptors may affect a number of cellular processes by their synergistic action on multiple targets. We discuss in detail sex differences in organelle function and in biological processes. We conclude that there is a need for a more detailed understanding of sex differences and their underlying mechanisms, which holds the potential to design new drugs that target sex-specific cardiovascular mechanisms and affect phenotypes. The comparison of both sexes may lead to the identification of protective or maladaptive mechanisms in one sex that could serve as a novel therapeutic target in one sex or in both.

Vildagliptin reduces cardiac ischemic-reperfusion injury in obese orchiectomized rats

Obesity and testosterone deprivation are associated with coronary artery disease. Testosterone and vildagliptin (dipeptidyl peptidase-4 inhibitors) exert cardioprotection during ischemic-reperfusion (I/R) injury. However, the effect of these drugs on I/R heart in a testosterone-deprived, obese, insulin-resistant model is unclear. This study investigated the effects of testosterone and vildagliptin on cardiac function, arrhythmias and the infarct size in I/R heart of testosterone-deprived rats with obese insulin resistance. Orchiectomized (O) or sham operated (S) male Wistar rats were divided into 2 groups to receive normal diet (ND) or high-fat diet (HFD) for 12 weeks. Orchiectomized rats in each diet were divided to receive testosterone (2 mg/kg), vildagliptin (3 mg/kg) or the vehicle daily for 4 weeks. Then, I/R was performed by a 30-min left anterior descending coronary artery ligation, followed by a 120-min reperfusion. LV function, arrhythmia scores, infarct size and cardiac mitochondrial function were determined. HFD groups developed insulin resistance at week 12. At week 16, cardiac function was impaired in NDO, HFO and HFS rats, but was restored in all testosterone- and vildagliptin-treated rats. During I/R injury, arrhythmia scores, infarct size and cardiac mitochondrial dysfunction were prominently increased in NDO, HFO and HFS rats, compared with those in NDS rats. Treatment with either testosterone or vildagliptin similarly attenuated these impairments during I/R injury. These finding suggest that both testosterone replacement and vildagliptin share similar efficacy for cardioprotection during I/R injury by decreasing the infarct size and attenuating cardiac mitochondrial dysfunction caused by I/R injury in testosterone-deprived rats with obese insulin resistance.

Karyopherin α2 induces apoptosis in tongue squamous cell carcinoma CAL-27 cells through the p53 pathway

Tumor onset and progression are associated with dysfunction of the nuclear transport machinery at the level of import and export receptors. However, the role of Karyopherin α2 (KPNA2) in human tongue squamous cell carcinoma (TSCC) remains unknown. We assessed the proliferation, apoptosis and migration of TSCC CAL-27 cells using wound healing, Transwell and MTT assays, western blotting, electron microscopy and acridine orange/ethidium bromide staining following knockdown of KPNA2. The results revealed the antiproliferative, proapoptotic and anti-migratory effects of KPNA2 silencing on the TSCC CAL-27 cells. Moreover, the knockdown of KPNA2 proved to be accompanied by the upregulation of active caspase-3, cytochrome c, Bax, Bad and decreased expression of Bcl-2, p-Bad and XIAP. KPNA2 activated the caspase-dependent pathway in the CAL-27 cells with upregulation of p53, p21Cip1/Waf1 and p16INK4a. Thus, the present study demonstrated that p53/p21Cip1/Waf1/p16INK4a may be an important pathway involved in the function of KPNA2 in TSCC CAL-27 cells.

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.

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.

Phosphorylation of AKT and abdominal aortic aneurysm formation

It is hypothesized that differential AKT phosphorylation between sexes is important in abdominal aortic aneurysm (AAA) formation. Male C57BL/6 mice undergoing elastase treatment showed a typical AAA phenotype (80% over baseline, P < 0.001) and significantly increased phosphorylated AKT-308 (p308) and total-AKT (T-AKT) at day 14 compared with female mice. Elastase-treated Raw cells produced increased p308 and significant amounts of matrix metalloproteinase 9 (MMP-9), and these effects were suppressed by LY294002 treatment, a known AKT inhibitor. Male and female rat aortic smooth muscle cells treated with elastase for 1, 6, or 24 hours demonstrated that the p308/T-AKT and AKT-Ser-473/T-AKT ratios peaked at 6 hours and were significantly higher in the elastase-treated cells compared with controls. Similarly, male cells had higher phosphorylated AKT/T-AKT levels than female cells. LY294002 also inhibited elastase-induced p308 formation more in female smooth muscle cells than in males, and the corresponding cell media had less pro-MMP-9. AKT siRNA significantly decreased secretion of pro-MMP-9, as well as pro-MMP-2 and active MMP-2 from elastase-treated male rat aortic smooth muscle cells. IHC of male mice AAA aortas showed increased p308, AKT-Ser-473, and T-AKT compared with female mice. Aortas from male AAA patients had a significantly higher p308/T-AKT ratio than female AAA tissues. These data suggest that AKT phosphorylation is important in the upstream regulation of MMP activity, and that differential phosphorylation may be important in sex differences in AAA.

Activity exerted by a testosterone derivative on myocardial injury using an ischemia/reperfusion model

Some reports indicate that several steroid derivatives have activity at cardiovascular level; nevertheless, there is scarce information about the activity exerted by the testosterone derivatives on cardiac injury caused by ischemia/reperfusion (I/R). Analyzing these data, in this study, a new testosterone derivative was synthetized with the objective of evaluating its effect on myocardial injury using an ischemia/reperfusion model. In addition, perfusion pressure and coronary resistance were evaluated in isolated rat hearts using the Langendorff technique. Additionally, molecular mechanism involved in the activity exerted by the testosterone derivative on perfusion pressure and coronary resistance was evaluated by measuring left ventricular pressure in the absence or presence of the following compounds: flutamide, prazosin, metoprolol, nifedipine, indomethacin, and PINANE TXA2. The results showed that the testosterone derivative significantly increases (P = 0.05) the perfusion pressure and coronary resistance in isolated heart. Other data indicate that the testosterone derivative increases left ventricular pressure in a dose-dependent manner (0.001-100 nM); however, this phenomenon was significantly inhibited (P = 0.06) by indomethacin and PINANE-TXA2  (P = 0.05) at a dose of 1 nM. In conclusion, these data suggest that testosterone derivative induces changes in the left ventricular pressure levels through thromboxane receptor activation.

Endurance exercise attenuates cardiotoxicity induced by androgen deprivation and doxorubicin

Doxorubicin (DOX) is associated with cardiac dysfunction and irreversible testicular damage. Androgen deprivation therapy (ADT) is administered prior to DOX treatment to preserve testicular function. However, ADT may exacerbate DOX-induced cardiac dysfunction. Exercise is cardioprotective, but the effects of exercise on cardiac function during combined ADT and DOX treatment are currently unknown. In this study, male Sprague-Dawley rats were randomly assigned to experimental groups: control (CON), ADT, DOX, or ADT+DOX. Animals received ADT or control implants on days 1 and 29 of the 56-day protocol. Animals remained sedentary (SED) or engaged in treadmill endurance exercise (TM) beginning on day 1. On day 15, the animals received DOX at 1 mg·(kg body mass)(-1)·d(-1) by intraperitoneal injection for 10 consecutive days, or an equivalent volume of saline. On day 57, cardiac function was assessed in vivo and ex vivo. Animals treated with DOX alone, or with combined ADT+DOX, showed significant (P < 0.05) reductions in left ventricular developed pressure (-21% and -27%), maximal rate of pressure development (-29% and -32%), and maximal rate of pressure decline (25% and 31%), respectively when compared with the sedentary control animals. Endurance exercise training attenuated (P > 0.05) cardiac dysfunction associated with combined ADT+DOX treatment, indicating that exercise during simultaneous ADT+DOX treatment is cardioprotective.

Major cardiac surgery induces an increase in sex steroids in prepubertal children

While the neuroprotective benefits of estrogen and progesterone in critical illness are well established, the data regarding the effects of androgens are conflicting. Surgical repair of congenital heart disease is associated with significant morbidity and mortality, but there are scant data regarding the postoperative metabolism of sex steroids in this setting. The objective of this prospective observational study was to compare the postoperative sex steroid patterns in pediatric patients undergoing major cardiac surgery (MCS) versus those undergoing less intensive non-cardiac surgery. Urinary excretion rates of estrogen, progesterone, and androgen metabolites (μg/mmol creatinine/m(2) body surface area) were determined in 24-h urine samples before and after surgery using gas chromatography-mass spectrometry in 29 children undergoing scheduled MCS and in 17 control children undergoing conventional non-cardiac surgery. Eight of the MCS patients had Down's syndrome. There were no significant differences in age, weight, or sex between the groups. Seven patients from the MCS group showed multi-organ dysfunction after surgery. Before surgery, the median concentrations of 17β-estradiol, pregnanediol, 5α-dihydrotestosterone (DHT), and dehydroepiandrosterone (DHEA) were (control/MCS) 0.1/0.1 (NS), 12.4/11.3 (NS), 4.7/4.4 (NS), and 2.9/1.1 (p=0.02). Postoperatively, the median delta 17β-estradiol, delta pregnanediol, delta DHT, and delta DHEA were (control/MCS) 0.2/6.4 (p=0.0002), -3.2/23.4 (p=0.013), -0.6/3.7 (p=0.0004), and 0.5/4.2 (p=0.004). Postoperative changes did not differ according to sex. We conclude that MCS, but not less intensive non-cardiac surgery, induced a distinct postoperative increase in sex steroid levels. These findings suggest that sex steroids have a role in postoperative metabolism following MCS in prepubertal children.

Expression of apoptosis-related genes in liver-specific growth hormone receptor gene-disrupted mice is sex dependent

Apoptosis is a process that affects life span and health. Mice with liver-specific disruption of the growth hormone receptor (GHR) gene (ie, Ghr gene) liver-specific growth hormone receptor knockout [LiGHRKO] mice), as opposed to mice with global deletion of the Ghr gene (GHRKO; Ghr-/-), are characterized by severe hepatic steatosis and lack of improved insulin sensitivity. We have previously shown that levels of proapoptotic factors are decreased in long-lived and insulin-sensitive GHRKO mice. In the current study, expression of specific apoptosis-related genes was assessed in brains, kidneys, and livers of male and female LiGHRKO and wild-type mice using real-time PCR. In the brain, expression of Caspase 3, Caspase 9, Smac/DIABLO, and p53 was decreased in females compared with males. Renal expression of Caspase 3 and Noxa also decreased in female mice. In the liver, no differences were seen between males and females. Also, no significant genotype effects were detected in the examined organs. Lack of significant genotype effect in kidneys contrasts with previous observations in GHRKO mice. Apparently, global GHR deletion induces beneficial changes in apoptotic factors, whereas liver-specific GHR disruption does not. Furthermore, sexual dimorphism may play an important role in regulating apoptosis during liver-specific suppression of the somatotrophic signaling.

Effectiveness of Panax ginseng on Acute Myocardial Ischemia Reperfusion Injury Was Abolished by Flutamide via Endogenous Testosterone-Mediated Akt Pathway

Mechanisms for Panax ginseng's cardioprotective effect against ischemia reperfusion injury involve the estrogen-mediated pathway, but little is known about the role of androgen. A standardized Panax ginseng extract (RSE) was orally given with or without flutamide in a left anterior descending coronary artery ligation rat model. Infarct size, CK and LDH activities were measured. Time-related changes of NO, PI3K/Akt/eNOS signaling, and testosterone concentration were also investigated. RSE (80 mg/kg) significantly inhibited myocardial infarction and CK and LDH activities, while coadministration of flutamide abolished this effect of RSE. NO was increased by RSE and reached a peak after 15 min of ischemia; however, flutamide cotreatment suppressed this elevation. Western blot analysis showed that RSE significantly reversed the decreases of expression and activation of PI3K, Akt, and eNOS evoked by ischemia, whereas flutamide attenuated the effects of these protective mechanisms induced by RSE. RSE completely reversed the dropping of endogenous testosterone level induced by I/R injury. Flutamide plus RSE treatment not only abolished RSE's effect but also produced a dramatic change on endogenous testosterone level after pretreatment and ischemia. Our results for the first time indicate that blocking androgen receptor abolishes the ability of Panax ginseng to protect the heart from myocardial I/R injury.

Manganese superoxide dismutase is reduced in the liver of male but not female humans and rodents with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is among the most common liver diseases. Oxidative stress is one of the pathogenic mechanisms contributing to the progression of simple fatty liver to non-alcoholic steatohepatitis (NASH). Manganese superoxide dismutase (MnSOD) is a mitochondrial antioxidative enzyme and here its expression in rodent and human NAFLD has been analyzed. MnSOD is found reduced in the liver of male mice fed a high fat diet and male ob/ob mice. Female mice fed an atherogenic diet to induce NASH have MnSOD protein levels comparable to controls. In a cohort of 30 controls, 41 patients with fatty liver and 39 NASH patients, MnSOD mRNA is significantly lower in the steatotic and NASH liver. When analyzed in both genders separately reduction of MnSOD expression is only found in males. Here, MnSOD mRNA negatively correlates with steatosis grade but not with extent of fibrosis or inflammation. MnSOD is, however, not reduced in primary human hepatocytes (PHH) treated with palmitate or oleate to increase cellular triglycerides. Lipopolysaccharide, TNF, IL-6, TGFβ and leptin which are all raised in NAFLD do not affect MnSOD in PHH. Adiponectin which attenuates oxidative stress partly by increasing MnSOD in macrophages does not induce MnSOD in PHH. In summary, current data show that hepatic MnSOD is reduced in male but not female humans and rodents with NAFLD.

Sex and sex hormones in cardiac stress--mechanistic insights

Important sex differences in the onset and characteristics of cardiovascular disease are evident, yet the mechanistic details remain unresolved. Men are more susceptible to cardiovascular disease earlier in life, though younger women who have a cardiovascular event are more likely to experience adverse outcomes. Emerging evidence is prompting a re-examination of the conventional view that estrogen is protective and testosterone a liability. The heart expresses both androgen and estrogen receptors and is functionally responsive to circulating sex steroids. New evidence of cardiac aromatase expression indicates local estrogen production may also exert autocrine/paracrine actions in the heart. Cardiomyocyte contractility studies suggest testosterone and estrogen have contrasting inotropic actions, and modulate Ca(2+) handling and transient characteristics. Experimentally, sex differences are also evident in cardiac stress responses. Female hearts are generally less susceptible to acute ischemic damage and associated arrhythmias, and generally are more resistant to stress-induced hypertrophy and heart failure, attributed to the cardioprotective actions of estrogen. However, more recent data show that testosterone can also improve acute post-ischemic outcomes and facilitate myocardial function and survival in chronic post-infarction. The myocardial actions of sex steroids are complex and context dependent. A greater mechanistic understanding of the specific actions of systemic/local sex steroids in different cardiovascular disease states has potential to lead to the development of cardiac therapies targeted specifically for men and women.

Sirtinol attenuates trauma hemorrhage-induced hepatic injury through Akt-dependent pathway in rats

BACKGROUND

Recent evidences show that sirtinol possesses anti-inflammatory properties and protective effects after shocklike states, but the mechanism of these effects remains unknown. Akt (also known as protein kinase B) exerts anti-inflammatory effects in injury. The aim of this study was to investigate whether Akt plays any role in the sirtinol-mediated attenuation of hepatic injury after trauma hemorrhage.

METHODS

Male Sprague-Dawley rats underwent trauma hemorrhage (mean blood pressure maintained at approximately 35-40 mm Hg for 90 minutes), followed by fluid resuscitation. During resuscitation, a single dose of sirtinol (1 mg/kg i.v.) with and without a PI3K inhibitor wortmannin (1 mg/kg i.v.), wortmannin, or vehicle was administered. Plasma alanine aminotransferase with aspartate aminotransferase (AST) concentrations and various hepatic parameters were measured (n = 8 rats per group) at 24 h after resuscitation. One-way analysis of variance and Tukey testing were used for statistical analysis.

RESULTS

Trauma hemorrhage increased hepatic myeloperoxidase activity, intercellular adhesion molecule-1 (ICAM-1) and interleukin-6 levels, and plasma alanine aminotransferase and aspartate aminotransferase concentrations. These parameters were significantly improved in the sirtinol-treated rats subjected to trauma hemorrhage. Sirtinol treatment also increased hepatic phospho-Akt expression compared with vehicle-treated trauma-hemorrhaged rats. The coadministration of wortmannin with sirtinol abolished the sirtinol-induced beneficial effects on the above parameters and hepatic injury.

CONCLUSION

These results suggest the protective effect of sirtinol administration on the alleviation of hepatic injury after trauma hemorrhage, which is, at least in part, through Akt-dependent pathway.

Androgen-STAT3 activation may contribute to gender disparity in human simply renal cysts

BACKGROUND

Simple renal cysts (SRC) are a common urological disease mostly in elderly, however the male-to-female ratio was 2.81. Androgen receptor (AR) activation was initially proposed as a vital signaling pathway in prostate cancer and consequent signal transducer and activator of transcription 3 (STAT3)-AR complex led an important putative mechanism by which prostate cells are sensitized with growth factor signals. However, in SRC disease, no related study emerged.

METHODS

30 patients with SRC and 20 age-matched healthy controls were recruited. Puncture biopsy was performed to acquire cyst-adjacent kidney tissue and normal kidney tissues were from healthy kidney donor who received living-related donor nephrectomy. The expression of STAT3 and androgen receptor was determined by immunohistochemical staining and western blotting. The in-vitro effect of androgen on human HK-2 (an immortalized proximal tubule epithelial cell line from normal adult human kidney) cells' STAT3 expression was analyzed as well.

RESULTS

Activated STAT3 was strongly expressed in tubular epithelial cells from kidneys of SRC patients, while it was barely found in normal kidneys. Meanwhile, the androgen receptor positive cyst epithelial cells and adjacent normal renal tubule cells were observed in kidneys from SRC patients, however, AR was weakly expressed in normal healthy male kidneys, statistically significant differences existed. In-vitro experiment demonstrated that when treated with exogenous added androgen, the expression level of STAT3 in HK-2 cells was significantly elevated.

CONCLUSIONS

Our data raised the possible novel evidence that androgen-STAT3 activation might contribute to gender disparity in human SRC disease and clarification the esoteric mechanisms will provide us attractive therapy target for cystic kidney disease.

Transient overexpression of TGFBR3 induces apoptosis in human nasopharyngeal carcinoma CNE-2Z cells

NPC (nasopharyngeal carcinoma) is a common malignancy in southern China without defined aetiology. Recent studies have shown that TGFBR3 (transforming growth factor type III receptor, also known as betaglycan), exhibits anticancer activities. This study was to investigate the effects of TGFBR3 on NPC growth and the mechanisms for its actions. Effects of TGFBR3 overexpression on cell viability and apoptosis were measured by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide], AO/EB (acridine orange/ethidium bromide) staining and electron microscopy in human NPC CNE-2Z cells. The expression of apoptosis-related proteins, p-Bad, Bad, XIAP (X-linked inhibitor of apoptosis), AIF (apoptosis-inducing factor), Bax and Bcl-2, was determined by Western blot or immunofluorescence analysis. Caspase 3 activity was measured by caspase 3 activity kit and [Ca²⁺]_i (intracellular Ca²⁺ concentration) was detected by confocal microscopy. Transfection of TGFBR3 containing plasmid DNA at concentrations of 0.5 and 1 μg/ml reduced viability and induced apoptosis in CNE-2Z in concentration- and time-dependent manners. Forced expression of TGFBR3 up-regulated pro-apoptotic Bad and Bax protein, and down-regulated anti-apoptotic p-Bad, Bcl-2 and XIAP protein. Furthermore, transient overexpression of TGFBR3 also enhanced caspase 3 activity, increased [Ca²⁺]_i and facilitated AIF redistribution from the mitochondria to the nucleus in CNE-2Z cells, which is independent of the caspase 3 pathway. These events were associated with TGFBR3-regulated multiple targets involved in CNE-2Z proliferation. Therefore transient overexpression of TGFBR3 may be a novel strategy for NPC prevention and therapy.

Estrogenic compounds are not always cardioprotective and can be lethal in males with genetic heart disease

Hypertrophic cardiomyopathy (HCM) is more severe in male than female mice eating a soy-based diet. We sought to determine whether the detrimental effects are mediated by the phytoestrogens present in soy, the mechanism by which phytoestrogens act, and to test whether estrogen modulates the sexually dimorphic phenotype. A soy-free diet (casein based) supplemented with the predominant phytoestrogens in soy, genistein and daidzein, recapitulated the fibrotic, proapoptotic and negative hemodynamic effects of soy in male hearts. As with the soy diet, the hearts of female HCM mice were not negatively affected by the phytoestrogen-containing diet. To determine the role of estrogen in the sex differences mediated by diet in HCM, gonadectomies were performed and estrogen was administered to male and female HCM mice on a casein- or phytoestrogen-supplemented diet. Somewhat surprisingly, estrogen was not protective in male or female mice with HCM and, in fact, was lethal in phytoestrogen-fed male mice with HCM. Because genistein is a potent tyrosine kinase inhibitor and tyrosine kinase inhibition has been associated with cardiotoxicity, we tested its effects in isolated adult cardiac myocytes. Genistein inhibited different tyrosine kinases depending on sex and, in combination with estrogen, resulted in apoptosis only in adult male cardiac myocytes. Finally, we show that phytoestrogens led to distinct programs of gene expression in hearts from males vs. females with HCM, suggesting mechanisms by which males are more sensitive to the detrimental effects of phytoestrogens and females are protected. These results implicate the phytoestrogen genistein in mediating cardiac pathology in males with HCM and, importantly, establish that estrogen is not protective in the setting of HCM.

Estrogens mediate cardiac hypertrophy in a stimulus-dependent manner

The incidence of cardiac hypertrophy, an established risk factor for heart failure, is generally lower in women compared with men, but this advantage is lost after menopause. Although it is widely believed that estrogens are cardioprotective, there are contradictory reports, including increased cardiac events in postmenopausal women receiving estrogens and enhanced cardiac protection from ischemic injury in female mice without estrogens. We exposed aromatase knockout (ArKO) mice, which produce no estrogens, to both pathologic and physiologic stimuli. This model allows an investigation into the effects of a complete, chronic lack of estrogens in male and female hearts. At baseline, female ArKO mice had normal-sized hearts but decreased cardiac function and paradoxically increased phosphorylation of many progrowth kinases. When challenged with the pathological stimulus, isoproterenol, ArKO females developed 2-fold more hypertrophy than wild-type females. In contrast, exercise-induced physiological hypertrophy was unaffected by the absence of estrogens in either sex, although running performance was blunted in ArKO females. Thus, loss of estrogen signaling in females, but not males, impairs cardiac function and sensitizes the heart to pathological insults through up-regulation of multiple hypertrophic pathways. These findings provide insight into the apparent loss of cardioprotection after menopause and suggest that caution is warranted in the long-term use of aromatase inhibitors in the setting of breast cancer prevention.