DOCK2 Promotes Atherosclerosis by Mediating the Endothelial Cell Inflammatory Response.

The pathology of atherosclerosis, a leading cause of mortality in patients with cardiovascular disease, involves inflammatory phenotypic changes in vascular endothelial cells. This study explored the role of the dedicator of cytokinesis (DOCK)-2 protein in atherosclerosis. Mice with deficiencies in low-density lipoprotein receptor and Dock2 (Ldlr-/-Dock2-/-) and controls (Ldlr-/-) were fed a high-fat diet (HFD) to induce atherosclerosis. In controls, Dock2 was increased in atherosclerotic lesions, with increased intercellular adhesion molecule (Icam)-1 and vascular cell adhesion molecule (Vcam)-1, after HFD for 4 weeks. Ldlr-/-Dock2-/- mice exhibited significantly decreased oil red O staining in both aortic roots and aortas compared to that in controls after HFD for 12 weeks. In control mice and in humans, Dock2 was highly expressed in the ECs of atherosclerotic lesions. Dock2 deficiency was associated with attenuation of Icam-1, Vcam-1, and monocyte chemoattractant protein (Mcp)-1 in the aortic roots of mice fed HFD. Findings in human vascular ECs in vitro suggested that DOCK2 was required in TNF-α-mediated expression of ICAM-1/VCAM-1/MCP-1. DOCK2 knockdown was associated with attenuated NF-κB phosphorylation with TNF-α, partially accounting for DOCK2-mediated vascular inflammation. With DOCK2 knockdown in human vascular ECs, TNF-α-mediated VCAM-1 promoter activity was inhibited. The findings from this study suggest the novel concept that DOCK2 promotes the pathogenesis of atherosclerosis by modulating inflammation in vascular ECs.

MARCH8 downregulation modulates profibrotic responses including myofibroblast differentiation.

Interstitial lung diseases can result in poor patient outcomes, especially in idiopathic pulmonary fibrosis (IPF), a severe interstitial lung disease with unknown causes. The lack of treatment options requires further understanding of the pathological process/mediators. Membrane-associated RING-CH 8 (MARCH8) has been implicated in immune function regulation and inflammation, however, its role in the development of pulmonary fibrosis and particularly the fibroblast to myofibroblast transition (FMT) remains a gap in existing knowledge. In this study, we demonstrated decreased MARCH8 expression in patients with IPF compared with non-PF controls and in bleomycin-induced PF. TGF-ß dose- and time-dependently decreased MARCH8 expression in normal and IPF human lung fibroblast (HLFs), along with induction of FMT markers α-SMA, collagen type I (Col-1), and fibronectin (FN). Interestingly, overexpression of MARCH8 significantly suppressed TGF-ß-induced expression of α-SMA, Col-1, and FN. By contrast, the knockdown of MARCH8 using siRNA upregulated basal expression of α-SMA/Col-1/FN. Moreover, MARCH8 knockdown enhanced TGF-ß-induced FMT marker expression. These data clearly show that MARCH8 is a critical "brake" for FMT and potentially affects PF. We further found that TGF-ß suppressed MARCH8 mRNA expression and the proteasome inhibitor MG132 failed to block MARCH8 decrease induced by TGF-ß. Conversely, TGF-ß decreases mRNA levels of MARCH8 in a dose- and time-dependent manner, suggesting the transcriptional regulation of MARCH8 by TGF-ß. Mechanistically, MARCH8 overexpression suppressed TGF-ß-induced Smad2/3 phosphorylation, which may account for the observed effects. Taken together, this study demonstrated an unrecognized role of MARCH8 in negatively regulating FMT and profibrogenic responses relevant to interstitial lung diseases.NEW & NOTEWORTHY MARCH8 is an important modulator of inflammation, immunity, and other cellular processes. We found that MARCH8 expression is downregulated in the lungs of patients with idiopathic pulmonary fibrosis (IPF) and experimental models of pulmonary fibrosis. Furthermore, TGF-ß1 decreases MARCH8 transcriptionally in human lung fibroblasts (HLFs). MARCH8 overexpression blunts TGF-ß1-induced fibroblast to myofibroblast transition while knockdown of MARCH8 drives this profibrotic change in HLFs. The findings support further exploration of MARCH8 as a novel target in IPF.

DOCK2 contributes to pulmonary fibrosis by promoting lung fibroblast to myofibroblast transition.

Idiopathic pulmonary fibrosis (IPF) is the most common chronic interstitial lung disease and is characterized by progressive scarring of the lung. Transforming growth factor-ß (TGF-ß) signaling plays an essential role in IPF and drives fibroblast to myofibroblast transition (FMT). Dedicator of cytokinesis 2 (DOCK2) is known to regulate diverse immune functions by activating Rac and has been recently implicated in pleural fibrosis. We now report a novel role of DOCK2 in pulmonary fibrosis development by mediating FMT. In primary normal and IPF human lung fibroblasts (HLFs), TGF-ß induced DOCK2 expression concurrent with FMT markers, smooth muscle α-actin (α-SMA), collagen-1, and fibronectin. Knockdown of DOCK2 significantly attenuated TGF-ß-induced expression of these FMT markers. In addition, we found that the upregulation of DOCK2 by TGF-ß is dependent on both Smad3 and ERK pathways as their respective inhibitors blocked TGF-ß-mediated induction. TGF-ß also stabilized DOCK2 protein, which contributes to increased DOCK2 expression. In addition, DOCK2 was also dramatically induced in the lungs of patients with IPF and in bleomycin, and TGF-ß induced pulmonary fibrosis in C57BL/6 mice. Furthermore, increased lung DOCK2 expression colocalized with the FMT marker α-SMA in the bleomycin-induced pulmonary fibrosis model, implicating DOCK2 in the regulation of lung fibroblast phenotypic changes. Importantly, DOCK2 deficiency also attenuated bleomycin-induced pulmonary fibrosis and α-SMA expression. Taken together, our study demonstrates a novel role of DOCK2 in pulmonary fibrosis by modulating FMT and suggests that targeting DOCK2 may present a potential therapeutic strategy for the prevention or treatment of IPF.

Abdominal Aortic Aneurysm Formation with a Focus on Vascular Smooth Muscle Cells.

Abdominal aortic aneurysm (AAA) is a lethal degenerative vascular disease that affects, mostly, the elder population, with a high mortality rate (>80%) upon rupture. It features a dilation of the aortic diameter to larger than 30 mm or more than 50%. Diverse pathological processes are involved in the development of AAA, including aortic wall inflammation, elastin breakdown, oxidative stress, smooth muscle cell (SMC) phenotypic switching and dysfunction, and extracellular matrix degradation. With open surgery being the only therapeutic option up to date, the lack of pharmaceutical treatment approach calls for identifying novel and effective targets and further understanding the pathological process of AAA. Both lifestyle and genetic predisposition have an important role in increasing the risk of AAA. Several cell types are closely related to the pathogenesis of AAA. Among them, vascular SMCs (VSMCs) are gaining much attention as a critical contributor for AAA initiation and/or progression. In this review, we summarize what is known about AAA, including the risk factors, the pathophysiology, and the established animal models of AAA. In particular, we focus on the VSMC phenotypic switching and dysfunction in AAA formation. Further understanding the regulation of VSMC phenotypic changes may provide novel therapeutic targets for the treatment or prevention of AAA.

PD-L1 mediates lung fibroblast to myofibroblast transition through Smad3 and ß-catenin signaling pathways.

Programmed death ligand-1 (PD-L1) is an immune checkpoint protein that has been linked with idiopathic pulmonary fibrosis (IPF) and fibroblast to myofibroblast transition (FMT). However, it remains largely unclear how PD-L1 mediates this process. We found significantly increased PD-L1 in the lungs of idiopathic pulmonary fibrosis patients and mice with pulmonary fibrosis induced by bleomycin and TGF-ß. In primary human lung fibroblasts (HLFs), TGF-ß induced PD-L1 expression that is dependent on both Smad3 and p38 pathways. PD-L1 knockdown using siRNA significantly attenuated TGF-ß-induced expression of myofibroblast markers α-SMA, collagen-1, and fibronectin in normal and IPF HLFs. Further, we found that PD-L1 interacts with Smad3, and TGF-ß induces their interaction. Interestingly, PD-L1 knockdown reduced α-SMA reporter activity induced by TGF-ß in HLFs, suggesting that PD-L1 might act as a co-factor of Smad3 to promote target gene expression. TGF-ß treatment also phosphorylates GSK3ß and upregulates ß-catenin protein levels. Inhibiting ß-catenin signaling with the pharmaceutical inhibitor ICG001 significantly attenuated TGF-ß-induced FMT. PD-L1 knockdown also attenuated TGF-ß-induced GSK3ß phosphorylation/inhibition and ß-catenin upregulation, implicating GSK3ß/ß-catenin signaling in PD-L1-mediated FMT. Collectively, our findings demonstrate that fibroblast PD-L1 may promote pulmonary fibrosis through both Smad3 and ß-catenin signaling and may represent a novel interventional target for IPF.

Allopurinol and valproic acid improve cardiac triglyceride and Na+-K+-ATPase activity independent of circulating aldosterone in female rats with glucose intolerance.

Context: Studies have shown that cardiac triglyceride accumulation and impaired Na+-K+-ATPase activity are linked to diabetes- related cardiovascular disease, particularly in women.Objectives: We hypothesised that allopurinol (ALL) and valproic acid (VPA) treatment would improve cardiac triglyceride and Na+-K+-ATPase activity independent of circulating aldosterone in Combined Oral Contraceptive (COC)-induced dysglycemiaMaterials and methods: Rats received COC (1.0 µg ethinylestradiol and 5.0 µg levonorgestrel; po) with or without ALL (1 mg; po) and VPA (20 mg; po) for 6 weeks.Results: COC-treatment led to impaired glucose tolerance, accumulated abdominal fat, dyslipidemia, elevated plasma MDA, PAI-1 and aldosterone levels and also reduced plasma nitric oxide bioavailability and cardiac Na+-K+-ATPase activity. However, either ALL or VPA treatment ameliorated these alterations comparably independent of elevated aldosterone levelDiscussion and conclusion: Our results suggest that either ALL or VPA would improve cardiac TG and Na+-K+-ATPase activity comparably in COC-treated rats, regardless of circulating aldosterone level.

DOCK2 Promotes Pleural Fibrosis by Modulating Mesothelial to Mesenchymal Transition.

Mesothelial to mesenchymal transition (MesoMT) is one of the crucial mechanisms underlying pleural fibrosis, which results in restrictive lung disease. DOCK2 (dedicator of cytokinesis 2) plays important roles in immune functions; however, its role in pleural fibrosis, particularly MesoMT, remains unknown. We found that amounts of DOCK2 and the MesoMT marker α-SMA (α-smooth muscle actin) were significantly elevated and colocalized in the thickened pleura of patients with nonspecific pleuritis, suggesting the involvement of DOCK2 in the pathogenesis of MesoMT and pleural fibrosis. Likewise, data from three different pleural fibrosis models (TGF-ß [transforming growth factor-ß], carbon black/bleomycin, and streptococcal empyema) consistently demonstrated DOCK2 upregulation and its colocalization with α-SMA in the pleura. In addition, induced DOCK2 colocalized with the mesothelial marker calretinin, implicating DOCK2 in the regulation of MesoMT. Our in vivo data also showed that DOCK2-knockout mice were protected from Streptococcus pneumoniae-induced pleural fibrosis, impaired lung compliance, and collagen deposition. To determine the involvement of DOCK2 in MesoMT, we treated primary human pleural mesothelial cells with the potent MesoMT inducer TGF-ß. TGF-ß significantly induced DOCK2 expression in a time-dependent manner, together with α-SMA, collagen 1, and fibronectin. Furthermore, DOCK2 knockdown significantly attenuated TGF-ß-induced α-SMA, collagen 1, and fibronectin expression, suggesting the importance of DOCK2 in TGF-ß-induced MesoMT. DOCK2 knockdown also inhibited TGF-ß-induced Snail upregulation, which may account for its role in regulating MesoMT. Taken together, the current study provides evidence that DOCK2 contributes to the pathogenesis of pleural fibrosis by mediating MesoMT and deposition of neomatrix and may represent a novel target for its prevention or treatment.

Dedicator of Cytokinesis 2 (DOCK2) Deficiency Attenuates Lung Injury Associated with Chronic High-Fat and High-Fructose Diet-Induced Obesity.

Obesity is a major risk factor for lung disease development. However, little is known about the impact of chronic high-fat and high-fructose (HFHF) diet-induced obesity on lung inflammation and subsequent pulmonary fibrosis. Herein we hypothesized that dedicator of cytokinesis 2 (DOCK2) promotes a proinflammatory phenotype of lung fibroblasts (LFs) to elicit lung injury and fibrosis in chronic HFHF diet-induced obesity. An HFHF diet for 20 weeks induced lung inflammation and profibrotic changes in wild-type C57BL/6 mice. CD68 and monocyte chemoattractant protein-1 (MCP-1) expression were notably increased in the lungs of wild-type mice fed an HFHF diet. An HFHF diet further increased lung DOCK2 expression that co-localized with fibroblast-specific protein 1, suggesting a role of DOCK2 in regulating proinflammatory phenotype of LFs. Importantly, DOCK2 knockout protected mice from lung inflammation and fibrosis induced by a HFHF diet. In primary human LFs, tumor necrosis factor-α (TNF-α) and IL-1ß induced DOCK2 expression concurrent with MCP-1, IL-6, and matrix metallopeptidase 2. DOCK2 knockdown suppressed TNF-α-induced expression of these molecules and activation of phosphatidylinositol 3-kinase/AKT and NF-κB signaling pathways, suggesting a mechanism of DOCK2-mediated proinflammatory and profibrotic changes in human LFs. Taken together, these findings reveal a previously unrecognized role of DOCK2 in regulating proinflammatory phenotype of LFs, potentiation of lung inflammation, and pulmonary fibrosis in chronic HFHF diet-caused obesity.

Acetate causes renoprotection like androgen and mineralocorticoid receptors blockade in testosterone-exposed pregnant rats.

The kidney plays a critical role in human health and deviation from its normal function can lead to severe morbidity and mortality. Exposure to excess testosterone in women has been linked to several disorders, including kidney disorder and acting undoubtedly through androgen receptor (AR), whereas the involvement of mineralocorticoid receptor (MR) is unclear. Likewise, the renal effect of sodium acetate (SAc) during late gestational exposure to testosterone is not well known. We hypothesized that SAc or MR blockade would protect the kidney of testosterone-exposed pregnant rats against glutathione and adenosine depletion. Twenty-five pregnant Wistar rats were treated (sc) with olive oil, testosterone propionate (0.5 mg/kg) singly or in combination with SAc (200 mg/kg; p.o.), androgen receptor (AR) blocker, flutamide (Flu; 7.5 mg/kg; p.o.) or (MR) blocker, eplerenone (Eple; 0.5 mg/kg) between gestational days 14 and 19. Glutathione, adenosine and nitric oxide were decreased while uric acid (UA), xanthine oxidase (XO), malondialdehyde (MDA), lactate dehydrogenase activity and free fatty acids were increased in the kidneys of gestational rats exposed to testosterone. Also, plasma urea and creatinine were elevated. SAc and Eple reversed tested testosterone-induced effects in gestational rats. The exposure to testosterone impairs renal antioxidant defense via AR and MR during late gestation in pregnant rats. The study also provides evidence that sodium acetate protects the kidneys of gestational testosterone-exposed rats against defective antioxidant defense in like manner as MR or AR antagonist.

Low dose spironolactone-mediated androgen-adiponectin modulation alleviates endocrine-metabolic disturbances in letrozole-induced PCOS.

Polycystic ovarian syndrome (PCOS), is a multifactorial endocrine disorder in women of reproductive age. It usually associates with metabolic disorders (MDs), which aggravates the risk of infertility, cardiometabolic events and associated comorbidities in women with PCOS. Adiponectin, a circulating protein produced by adipocytes, which has been suggested to inversely correlate with MDs. Spironolactone, a non-selective mineralocorticoid receptor (MR) antagonist, has been in wide clinical use for several decades. Herein, we investigated the effects of low dose spironolactone (LDS) and the role of adiponectin in endocrine-metabolic disturbances in experimentally-induced PCOS rats. Eighteen female Wistar rats (160-180 g) were randomly allotted into 3 groups and treated with vehicle (p.o.), letrozole (LET; 1 mg/kg) and LET + LDS (0.25 mg/kg), once daily for 21 days, respectively. The results showed that LET-treated animals had features of PCOS, characterized by elevated plasma testosterone and prolactin, increased body weight gain and ovarian weight as well as disrupted ovarian cytoarchitecture and degenerated follicles. Additionally, elevated fasting blood glucose, 1 h-postload glucose and plasma insulin, impaired glucose tolerance, insulin resistance, reduced insulin sensitivity, increased plasma and ovarian lipid profile, plasma lipid peroxidation, TNF-α, IL-6 and decreased plasma glutathione peroxidase and glutathione content were observed. These alterations were associated with decreased circulating adiponectin and were reversed when treated with LDS. The present results suggest that LDS ameliorates endocrine-metabolic disturbances and inflammation-related comorbidities associated with LET-induced PCOS by modulating circulating androgen-adiponectin status.

Sodium butyrate arrests pancreato-hepatic synchronous uric acid and lipid dysmetabolism in high fat diet fed Wistar rats.

High fat diet (HFD) is a risk factor for metabolic syndrome which is characterized by overt glucose dysmetabolism and tissue derangement. The liver and pancreas are important metabolic tissues with anatomical proximity sharing splanchnic and mesenteric circulation but it is unclear whether, there is an associated metabolic status between the two organs in health and disease. Uric acid (UA) hypersecretion and ectopic lipid accumulation are characteristic pathophysiology of an array of non-communicable diseases. Sodium butyrate (BUT) is reputed for therapeutic roles in metabolic derangement. Therefore, the present study investigated synchrony in hepatic and pancreatic UA and lipid metabolic status in HFD-induced glucose dysregulation and probed the beneficial effects of BUT. Twenty-four female Wistar rats were treated with normal rat chow and distilled water (po) or sodium butyrate (200 mg/kg; po) or high fat diet and distilled water (po) or high fat diet and sodium butyrate. Results showed that HFD increased plasma, pancreatic and hepatic triglyceride, triglyceride-glucose index, malondialdehyde, uric acid (UA), lactate dehydrogenase but reduced glucose-6-phosphate dehydrogenase. Histological analysis revealed hepatic and pancreatic architectural derangement and cellular degeneration in HFD-fed animals. However, BUT reversed the HFD-induced systemic, pancreatic and hepatic synchronous dysmetabolism with evidence of improved histology. HFD-induced lipid and UA alterations were synchronous in the pancreas and liver. BUT elicits beneficial effects on systemic and tissue HFD-induced deleterious metabolic changes which were synchronized in pancreas and liver of rats.

Frequent exposure to varied home cage sizes alters pain sensitivity and some key inflammation-related biomarkers.

BACKGROUND: Nature and size of rodent cages vary from one laboratory or country to another. Little is however known about the physiological implications of exposure to diverse cage sizes in animal-based experiments. METHOD: Here, two groups of male Swiss mice (Control group - Cage stationed, and Test group - Cage migrated) were used for this study. The cage-migrated mice were exposed daily to various cage sizes used across laboratories in Nigeria while the cage-stationed mice exposed daily to different but the same cage size and shape. At the end of the 30 days exposure, top-rated paradigms were used to profile changes in physiological behaviours, and this was followed by evaluation of histological and biochemical metrics. RESULTS: The study showed a significant (p < 0.05) decrease in blood glucose levels (at 60 and 120 min of oral glucose tolerance test) in the cage-migrated mice compared to cage-stationed mice. Strikingly, peripheral oxidative stress (plasma malondialdehyde) and pain sensitivity (formalin test, hot-and-cold plate test, and von Frey test) decreased significantly in cage-migrated mice compared to cage-stationed animals. Also, the pro-inflammation mediators (IL-6 and NF-κB) increased significantly in cage-migrated mice compared to cage-stationed mice. However, emotion-linked behaviours, neurotransmitters (serotonin, noradrenaline and GABA), brain and plasma electrolytes were not significantly difference in cage-migrated animals compared to cage-stationed mice. CONCLUSION: Taken together, these results suggest that varied size cage-to-cage exposure of experimental mice could affect targeted behavioural and biomolecular parameters of pain and inflammation, thus diminishing research reproducibility, precipitating false negative/positive results and leading to poor translational outcomes.

Spironolactone reversed hepato-ovarian triglyceride accumulation caused by letrozole-induced polycystic ovarian syndrome: tissue uric acid-a familiar foe.

Polycystic ovarian syndrome (PCOS) is a complex endocrine disease among women of reproductive age and is one of the main causes of infertility. Non-alcoholic fatty liver disease (NAFLD), the most prominent chronic liver disease in adults, is characterized by excess hepatic triglyceride (TG) accumulation. PCOS women have increased risk of NAFLD and uric acid has been documented to have a positive correlation with subclinical tissue damage and might be the link in the cystic. Spironolactone (SPL) is a mineralocorticoid receptor (MR) blocker that has been in wide clinical use for some decades. In this research, we investigated the effects of SPL on ovarian and hepatic tissue damage in experimental PCOS rats induced by letrozole (LET). A total of eighteen adult female Wistar rats were used for this study and the animals divided into 3 groups are treated with vehicle, LET (1 mg/kg), and LET+SPL (SPL; 0.25 mg/kg), p.o. once daily respectively for 21 uninterrupted days. Results showed that LET treatment induced features of PCOS characterized by increased plasma testosterone (T) and luteinizing hormone (LH) together with increased body weight. Abnormal ovarian and hepatic histomorphological changes were also observed with elevated uric acid (UA) and TG accumulation in both tissues respectively. Treatment with SPL however attenuated the elevated testosterone in the LET-induced PCOS model accompanied with a reversal in the observed ovarian and hepatic UA, TG accumulation, and altered histomorphological changes. Taken together, spironolactone reversed the PCOS-induced ovarian and hepatic tissue damage by suppressing tissue UA and TG accumulation.

Combined but not single treatment with ethinylestradiol/levonorgestrel and spironolactone reduces plasminogen activator inhibitor-1 in insulin-resistant ovariectomised rats.

OBJECTIVE: Increased circulating level of plasminogen activator inhibitor-1 (PAI-1) is associated with menopausal oestrogen deficiency. We therefore hypothesised that the combined oral contraceptive (COC) with spironolactone (SPL) improves insulin resistance (IR) in ovariectomised (OVX) rats by reducing circulating PAI-1. METHODS: Twelve-week-old female Wistar rats were divided into sham-operated (SHM), OVX, OVX+SPL (0.25 mg/kg), COC (1.0 µg ethinylestradiol and 5.0 µg levonorgestrel) and OVX+COC+SPL rats treated with COC and SPL daily for eight weeks. IR was assessed by homeostatic model assessment of IR (HOMA-IR). RESULTS: Data showed that OVX rats had a higher HOMA-IR value that is associated with increased visceral adiposity, triglycerides (TG), total cholesterol/high-density lipoprotein cholesterol (HDL-C), TG/HDL-C, plasma insulin, GSK-3, corticosterone and decreased 17ß-oestradiol. However, these effects were attenuated in OVX+COC, OVX+SPL and OVX+COC+SPL rats compared to OVX rats. OVX rats had lower PAI-1 than SHM rats, whereas the beneficial effect on IR and other parameters by COC or SPL was accompanied with increased PAI-1. Improvement of IR and other parameters with combined COC and SPL in OVX rats was accompanied with reduced PAI-1. CONCLUSION: Taken together, COC or SPL improves IR independent of PAI-1, whereas a combination of COC and SPL in OVX rats ameliorates IR in a PAI-1-dependent manner.

Drospirenone-containing oral contraceptives do not affect glucose regulation and circulating corticosterone.

Background Combined oral contraceptive (COC) use has been associated with an increased risk of insulin resistance (IR) and other adverse cardiovascular events, despite efforts to reduce the dosage and/or progestin type. COC containing drospirenone (DRSP) is an analog of spironolactone, hence its antimineralocorticoid and antiandrogenic characteristics have been deemed beneficial, although the benefits and/or negative outcome of its usage have not been fully elucidated. We therefore hypothesized that COC with DRSP component will not affect glucose regulation and circulating corticosterone. Method Ten-week-old female Wistar rats were divided into three groups: control (CON), ethinylestradiol/drospirenone COC (EE/DRSP)-treated, and ethinylestradiol/levonorgestrel COC (EE/LN)-treated rats. The treatment lasted for 8 weeks. Results Results showed that with the exception of lipid profiles, EE/LN but not EE/DRSP COC treatment affected body weight, glucose tolerance, plasma insulin, corticosterone, (IR), and pancreatic ß-cell dysfunction. Conclusion Taken together, the findings showed that the beneficial effect of EE/DRSP could possibly be through the DRSP component. The result also implies that COCs containing DRSP may be a better and safer means of contraception than those with LN with less cardiovascular risks.

Very low dose spironolactone protects experimentally-induced polycystic ovarian syndrome from insulin-resistant metabolic disturbances by suppressing elevated circulating testosterone.

Polycystic ovarian syndrome (PCOS) is the most common endocrinological disorder in women of reproductive age and hyperandrogenism is a prominent feature of PCOS resulting in infertility and increased risk of developing metabolic disorders including insulin resistance (IR), abdominal adiposity, glucose intolerance and cardiovascular diseases. Spironolactone (SPL), a non-selective mineralocorticoid receptor (MR) antagonist, has been in wide clinical use for several decades. In this study, we investigated the effects of SPL on IR and metabolic disturbances in letrozole-induced PCOS rats. Eighteen adults female Wistar rats were randomly divided into 3 groups and treated with vehicle, letrozole (LET; 1 mg/kg) and LET + SPL (SPL; 0.25 mg/kg), p.o. once daily for 21 consecutive days. Results showed that LET treatment induced PCOS characterised by elevated plasma testosterone and luteinizing hormone (LH) accompanied with increased body weight and visceral adiposity, IR, glucose intolerance, dyslipidemia and altered histomorphological ovaries. Treatment with SPL however attenuated the elevated testosterone in LET-induced PCOS model accompanied with a reversal in all the observed alterations. Taken together, analysis of the physical, biochemical and histological evidences shows that the protective effect of this very low dose spironolactone may be through its anti-androgenic mechanism.

Sodium butyrate recovers high-fat diet-fed female Wistar rats from glucose dysmetabolism and uric acid-associated cardiac tissue damage.

Increased global consumption of high-fat/high-calorie diet has led to higher incidence of the multifactorial cardiometabolic syndrome especially among women. The links between glucose deregulation and eventual mortal cardiac diseases are still being investigated. However, several reports have implicated elevated uric acid (UA) in the progression of metabolic disorders especially during high-fructose diet. Also, butyrate (BUT) a short-chain fatty acid is being identified with intriguing therapeutic potentials in metabolic disorders. We therefore hypothesized that high-fat diet-induced glucose deregulation and cardiac tissue damage are associated with elevated UA and attenuated by BUT in female rats. Twenty-four 10-week-old female Wistar rats with weights ranging from 135 to 150 g were treated with normal rat chow and distilled water (po) or sodium butyrate (200 mg/kg; po) or high-fat diet and distilled water (po) or high-fat diet and sodium butyrate. Treatments lasted for 6 weeks. Results showed that high-fat diet caused glucose dysmetabolism, elevated plasma triglyceride (TG), total cholesterol (TC), corticosterone, malondialdehyde (MDA), plasma and cardiac UA, and lactate dehydrogenase (LDH). High-fat diet also led to depressed reduced glutathione (GSH). Histological analysis of cardiac tissue showed cellular infarction, infiltration, and fibrosis in high-fat diet-fed rats. However, all these effects were ameliorated by BUT treatment. The findings here showed that high-fat diet resulted in glucose dysmetabolism and cardiac tissue damage through a UA-dependent mechanism and that BUT can protect against high-fat diet-induced cardiometabolic disorders through UA suppression and augmentation of glutathione antioxidant defenses.

Drospirenone-containing contraceptive exerts positive effects on cardiac uric acid and PAI-1 but not GSK-3: Improved safety profiles in contraception?

The use of combined oral contraceptives (COC) have been associated with increased risk of adverse cardiovascular events and elevated cardiac and circulating plasminogen activator inhibitor-1 (PAI-1) and glycogen synthase kinase-3 (GSK-3) have been implicated in these events. Contraceptives containing drospirenone, a progestin with anti-androgenic actions may have a positive or neutral effect on cardiac PAI-1 and GSK-3 levels. Studies on the favorable effects of oral contraceptives containing drospirenone when compared with other androgenic contraceptives have not been fully elucidated. We therefore sought to compare the effect of a contraceptive containing ethinyl estradiol and drospirenone (DSP) with a contraceptive containing ethinyl estradiol and levonorgestrel (LVG) on cardiac uric acid (UA), PAI-1, GSK-3 and some hematological parameters. Ten weeks old female Wistar rats were divided into three groups; control (CON), LVG or DSP treated rats. The treatment lasted for 8 weeks. Results showed that LVG and not DSP treatment led to increase in plasma and cardiac tissue UA, plasma and cardiac PAI-1 as well as granulocyte-lymphocyte ratio (GLR) and platelet-lymphocyte ratio (PLR). However, the DSP treatment affected the circulating GSK-3. Taken together, the findings showed that LVG and not DSP affected cardiac UA and PAI-1. These results suggest that COC containing drospirenone appears to have positive effects on cardiac UA and PAI-1 levels but do not affect GSK-3, hence, COC containing drospirenone may be a better and safer means of contraception compared to androgenic contraceptives.

Ameliorative effect of low-dose spironolactone on obesity and insulin resistance is through replenishment of estrogen in ovariectomized rats.

Women have a lower incidence of cardiovascular diseases (CVD) than men at a similar age but the reverse is the case after menopause, indicating a possible protective effect of estrogen on cardiometabolic function. Although various hormonal therapies have been formulated to combat the CVD risks in postmenopausal state, the beneficial effects have not been consistent. Obesity with insulin resistance (IR) is closely linked to CVD risks while ovariectomized rodents have been shown to mimic a state of obesity and IR. We therefore hypothesized that low-dose spironolactone would ameliorate obesity and IR in estrogen-deprived rats by replenishing estrogen and suppressing elevated glycogen synthase kinase-3 (GSK-3). Ten-week-old female Wistar rats were divided into 4 groups: sham-operated (SHM), spironolactone (SPL; 0.25 mg/kg), and ovariectomized (OVX) rats treated with or without spironolactone daily for 8 weeks. Results showed that estrogen deprivation through ovariectomy caused increased body mass gain and visceral adiposity that are accompanied by increased HOMA-IR, HOMA-ß, 1-hour postload glucose, glucose intolerance, platelet/lymphocyte ratio, plasma insulin, atherogenic dyslipidemia, uric acid, GSK-3, corticosterone, and aldosterone and depressed 17ß-estradiol. However, treatment of OVX rats with spironolactone ameliorated all these effects. Taken together, the results demonstrate that treatment with low-dose spironolactone improves obesity and IR, which appears to involve replenishment of estrogen and suppression of GSK-3 along with circulating mineralocorticoid and glucocorticoid. The findings imply a positive cardiometabolic effect of low-dose spironolactone usage in estrogen-deprived conditions.

Oral hormonal therapy with ethinylestradiol-levonorgestrel improves insulin resistance, obesity, and glycogen synthase kinase-3 independent of circulating mineralocorticoid in estrogen-deficient rats.

Estrogen deficiency has been associated with increased incidence of cardiovascular diseases , and recent clinical trials of standard formulations of hormonal therapies have not demonstrated consistent beneficial effects. Estrogen-progestin therapy has been used as exogenous estrogen to normalize depressed estrogen level during menopause. Ovariectomized rodents mimic an estrogen-deficient state in that they develop cardiometabolic dysfunction, including insulin resistance (IR). We therefore hypothesized that hormonal therapy with combined oral contraceptive steroids, ethinylestradiol-levonorgestrel (EEL), improves IR, obesity, and glycogen synthase kinase-3 (GSK-3) through reduction of circulating mineralocorticoid in ovariectomized rats. Twelve-week-old female Wistar rats were divided into 4 groups: sham-operated (SHM) and ovariectomized (OVX) rats were treated with or without EEL (1.0 µg ethinylestradiol and 5.0 µg levonorgestrel) daily for 8 weeks. Results showed that OVX or SHM + EEL treated rats had increased HOMA-IR (homeostatic model assessment of IR), 1 h postload glucose, HOMA-ß, triglycerides (TG), total cholesterol (TC), TC/HDL cholesterol, TG/HDL cholesterol, plasma insulin, GSK-3, corticosterone, and aldosterone. On the other hand, OVX + EEL treatment ameliorated all these effects except that of aldosterone. Taken together, the results demonstrate that oral hormonal replacement with EEL improves IR and pancreatic ß-cell function and suppresses GSK-3 and glucocorticoid independent of circulating aldosterone, suggesting a positive cardiometabolic effect of oral EEL therapy in estrogen-deficient rats.