Insights Into the Cardiomodulatory Effects of Sex Hormones: Implications in Transgender Care

Transgender individuals that undergo gender-affirming hormone therapy may experience discrimination in the health care setting with a lack of access to medical personnel competent in transgender medicine. Recent evidence suggests that gender-affirming hormone therapy is associated with an increased risk of cardiovascular diseases and cardiovascular risk factors. A recent statement from the American Heart Association reinforces the importance of cardiovascular-focused clinical management and the necessity for more research into the impact of gender-affirming hormone therapy. With this in mind, this review will highlight the known cardiovascular risk factors associated with gender-affirming hormone therapy and identify potential molecular mechanisms determined from the limited animal studies that explore the role of cross-sex steroids on cardiovascular risk. The lack of data in this understudied population requires future clinical and basic research studies to inform and educate clinicians and their transgender patient population to promote precision medicine for their care to improve their quality of life.

The dual inhibitor Sacubitril-valsartan ameliorate high-fat high-fructose-induced metabolic disorders in rats superiorly compared to valsartan only

OBJECTIVES

Sacubitril-valsartan, a recently approved treatment for heart failure, has shown some promise as a possible therapeutic option for diabetes mellitus. It is still not clear whether those beneficial effects are comparable to valsartan effects. In this work, we aimed at investigating Sacubitril-valsartan effect on metabolic changes in a model of high-fat high fructose diet-induced diabetes mellitus, in comparison to the metabolic changes induced by valsartan only.

METHODS

Rats were ad libitum fed with either standard chow plus tap water for drinking (controls) or 60% beef tallow and 10% fructose drinking water (diseased) for 11 weeks. Starting in week 9, each group was subdivided into four, namely vehicle, pioglitazone, Sacubitril-valsartan and valsartan. Treatments were administered from weeks 9 to 11, while rats were maintained in their respective diet groups.

KEY FINDINGS

Sacubitril-valsartan treatment significantly decreased daily food intake, body weight and epididymal white adipose weight, and normalized insulin and glycosylated haemoglobin in high-fat high fructose. Both valsartan and Sacubitril-valsartan only attenuated the elevated fasting blood glucose levels, glucose, insulin and pyruvate tolerance and increased protein kinase B phosphorylation in diseased rats.

CONCLUSIONS

Sacubitril-valsartan may be an effective modulator of diabetes mellitus-associated metabolic aberration, superiorly compared to valsartan only.

Abstract 077: 17b-estradiol Implants With An Antiandrogen Or Castration Attenuate Body Weight And Total Lean Mass But Differentially Modulate Total Cholesterol And The Pressor Response To Chronic Angiotensin II In The Male Rat

Background: Transfemales are biological males at birth, but identify as female by gender. Gender-Affirming Hormone Therapy ( GAHT ) is used to alter hormone levels to match gender identity. GAHT in transfemales involves administration of estradiol ( E2 ) with an androgen antagonist ( AA ) or orchiectomy. Sex is an independent predictor of cardiovascular ( CV ) risk, but the role of sex hormones on CV risk in transfemales is unknown. Thus, this study tested the hypothesis that GAHT in male rats increases CV risk.

Methods: Male Sprague Dawley ( SD ) rats were randomly assigned at 14 weeks of age to three groups that underwent either mean arterial pressure ( MAP , N=3-5/group) or metabolic (N=8/group) monitoring. Control ( C ): empty silastic capsule. E2+AA: silastic capsule with 17-beta E2 benzoate (5 mg/21 days) plus AA, spironolactone (10 mg/kg/day, incorporated in diet). E2+CTX: silastic capsule with E2 plus castration ( CTX ). Silastic capsules (+/- E2) were replaced every 21 days starting at 14 weeks. AA, started at 14 weeks of age, was continued in E2+AA but discontinued after CTX at 16 weeks of age in E2+CTX.

Results: (Table 1) : The pressor response to angiotensin II ( ANG II ) was similar in C and E2+CTX but was blunted in E2+AA despite similar baseline MAP, increase in E2 and decrease in testosterone. Cholesterol was only increased in E2+AA.

Conclusion: These results suggest that feminizing therapy in male rats is associated with similar changes in sex steroids but the pressor response to ANG II and lipid profile differ based on the method of androgen reduction. The use of a transfemale rodent model will allow study of the pathophysiology of increased CV risk associated with GAHT across the lifespan.

Abstract P048: Western Diet Consumption Exacerbates Hypertension In Hyperandrogenemic Female Rat, A Model Of Polycystic Ovary Syndrome

Background: Polycystic ovary syndrome ( PCOS ) is the most common endocrinopathy affecting women of reproductive age. It is characterized by hyperandrogenemia, increased blood pressure ( BP ) and metabolic dysfunction. Consumption of western diet ( WD ) aggravates the reproductive and metabolic phenotypes of PCOS. Yet, the effect of WD consumption on BP in PCOS women is not clear. Therefore, this study was undertaken to test the hypothesis that WD consumption in hyperandrogenemic female ( HAF ) rats (a model that mimics most of PCOS symptoms) increases BP along with increasing renal expression of the vasoconstrictor ( VC ) components of the renin-angiotensin system ( RAS ).

Methods: At 4 wks of age, female Sprague Dawley rats were implanted (s.c.) with either 5α-dihydrotestosterone pellets (7.5 mg/90 d; HAF rats) or placebo pellets (controls; CON) , that were replaced throughout life. At 4 wks of age, HAF and CON rats were also started on WD (high fat and high sucrose content) or control diet ( CD ), thus forming 4 groups; CON-CD, CON-WD, HAF-CD and HAF-WD. At 20 wks of age, rats were implanted with radiotelemetry transmitters in the abdominal aorta to measure mean arterial pressure ( MAP ) [n=4-5/group]. Another set of rats (n=3-6/group) were euthanized and kidneys collected for measurement of components of the RAS by western blot.

Results: are shown in Table 1 .

Conclusion: WD consumption in HAF results in further increases in BP, despite upregulation of components of the intrarenal vasodilator RAS (ACE2 and AT2R), which is likely a protective mechanism. Future studies will determine the role(s) of other major VC pathways (e.g. endothelin system) in hypertension in WD-fed HAFs.

Polycystic Ovary Syndrome: Insights from Preclinical Research

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, affecting approximately 10%. PCOS is diagnosed by the presence of at least two of these three criteria: hyperandrogenemia, oligo- or anovulation, and polycystic ovaries. The most common type (80%) of PCOS includes hyperandrogenemia. PCOS is also characterized by obesity or overweight (in 80% of US women with PCOS), insulin resistance with elevated plasma insulin but not necessarily hyperglycemia, dyslipidemia, proteinuria, and elevated BP. Although elevated compared with age-matched controls, BP may not reach levels considered treatable according to the current clinical hypertension guidelines. However, it is well known that elevated BP, even modestly so, increases the risk of cardiovascular disease. We have developed a model of hyperandrogenemia in rodents that mimics the characteristics of PCOS in women, with increases in body weight, insulin resistance, dyslipidemia, andproteinuria and elevated BP. This review discusses potential mechanisms responsible for the elevated BP in the adult and aging PCOS rat model that may be extrapolated to women with PCOS.

Trimetazidine, a metabolic modulator, attenuates silica-induced pulmonary fibrosis and decreases lactate levels and LDH activity in rats

Pulmonary fibrosis has been recently linked to metabolic dysregulation. Silica-induced pulmonary fibrosis in rats was employed by the current study to explore the effects of trimetazidine (a metabolic modulator-antianginal drug; TMZ) on silica-induced pulmonary fibrosis. Pulmonary fibrosis was induced by intranasal instillation of silica (50 mg/100 µl/rat) in TMZ versus vehicle-treated rats. Body weights of rats, weights of lungs, and wet-to-dry lung weights were determined. Various parameters were also measured in serum, bronchoalveolar lavage fluid (BALF) in addition to lung tissue homogenates. Moreover, histopathological examination of sectioned lungs for lesion score and distribution and histochemical detection of myeloperoxidase (MPO) in lung tissues were also performed. No significant differences were observed in body weight gains, lung coefficients, lung weights, and wet-to-dry lung weight in silica versus control rats. Elevated lactate levels in serum and lung homogenates were significantly attenuated by TMZ. In addition, lactate dehydrogenase activity, transforming growth factor-β, and total proteins in BALF were significantly normalized with TMZ. Moreover, TMZ significantly increased reduced glutathione and adenosine triphosphate levels and decreased nitrate/nitrite and hydroxyproline content in lungs of silica-treated rats. Histopathological examination of lungs revealed more than 56% reduction in lesion score and distribution by TMZ. MPO expression in lungs of silica-treated rats was also significantly attenuated by TMZ. TMZ attenuates silica-induced pulmonary fibrosis, an effect that could be mediated by suppressing anaerobic glycolysis-induced excessive lactate production. Regulation of oxidative stress could also play a role in TMZ-promoted protective effects.

Cardiovascular disease risk in offspring of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder affecting women at reproductive age. PCOS diagnosis (Rotterdam criteria) is based on the presence of two out of three criteria; clinical and/or biochemical hyperandrogenism, oligo- or an-ovulation and polycystic ovaries. PCOS women suffer from a constellation of reproductive and metabolic abnormalities including obesity and insulin resistance. PCOS women also have increased blood pressure and increased risk of cardiovascular diseases (CVD). In-utero, offspring of PCOS women are exposed to altered maternal hormonal environment and maternal obesity (for most of PCOS women). Offspring of PCOS women could also be subject to genetic susceptibility, the transgenerational transmission of some of the PCOS traits or epigenetic changes. Offspring of PCOS women are commonly reported to have an abnormal birth weight, which is also a risk factor for developing CVD and hypertension later in life. Although studies have focused on the growth pattern, reproductive and metabolic health of children of PCOS women, very limited number of studies have addressed the risk of hypertension and CVD in those offspring particularly as they age. The current narrative review is designed to summarize the available literature (both human studies and experimental animal studies) and highlight the gaps in addressing hypertension and CVD risks in offspring of PCOS women or hyperandrogenemic female animal models.

Abstract P184: Aging Male Offspring Of Polycystic Ovary Syndrome Rat Model Have Normal Blood Pressure And Exaggerated Pressor Response To Angiotensin II

Background: Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenemia and elevated blood pressure (BP). Male offspring of hyperandrogenemic female (HAF) rats, PCOS model, have low birth weight, with normal BP, but exaggerated pressor response to Angiotensin (Ang) II as adults. The present study tested the hypothesis that with aging, male HAF offspring are at increased risk of developing hypertension (HT).

Methods: Hyperandrogenemia was induced in female SD rats (5α-dihydrotestosterone pellets 7.5 mg/90 d, s.c. at 4 wks of age and throughout life). HAF and controls (10-12 wks of age) were mated, allowed to deliver and lactate. HAF and control male offspring (F1 HAF and F1 Contr. ) were left untreated until 16-20 mos of age. Body composition (echoMRI) and proteinuria were measured in aging offspring. BP was measured (baseline; 9 d, enalapril (25 mg/kg/d); 7d) by telemetry. Rats were then given Ang II (50 ng/kg/min, s.c. minipumps) or saline (No Ang II) for 13 d. High salt (4%) diet (HSD) was started for both Ang II and No Ang II groups on day 8 of Ang II.

Results: Aging male F1 HAF had similar fat mass, but lower lean mass (433.7 ± 6 vs 453.6 ± 7 g, p< 0.05) and body weight (552.3 ± 11 vs 590.4 ± 11 g, n = 8-16, p<0.05) than F1 Contr. . Despite higher proteinuria in F1 HAF (412 ± 42 mg/24h vs 292 ± 47 mg/24h, n = 11-13, p<0.05), baseline mean arterial pressure (MAP) was similar between F1 HAF and F1 Contr. (130 ± 1 mmHg vs 126 ± 4 mmHg, respectively, n = 8, p=NS). Enalapril decreased MAP similarly in both F1 HAF and F1 Contr. (110 ± 2 mmHg vs 107 ± 3 mmHg, respectively). On low salt, Ang II increased MAP to higher levels in F1 HAF than F1 contr., saline-treated>F1 HAF and F1 Contr. (140 ± 11 mmHg vs 119 ± 10 mmHg, 105 ± 3 mmHg and 103 ± 4 mmHg, respectively, n = 4, p<0.05 F 1 HAF vs other grps). With 6 days of HSD, MAP was similar between F1 HAF and F1 Contr. not treated with Ang II (142 ± 6 mmHg and 132 ± 9 mmHg, respectively). MAP was also similar between F1 HAF and F1 Contr. with Ang II (169 ± 1 mmHg and 159 ± 9 mmHg, respectively). However, both Ang II-treated groups had significantly higher MAP compared to their respective No Ang II control groups.

Conclusion: Aging male HAF offspring do not develop hypertension, but are at increased risk of renal injury and cardiovascular disease due to enhanced pressor sensitivity to Ang II.

Cardiometabolic consequences of maternal hyperandrogenemia in male offspring

Polycystic ovary syndrome (PCOS) in women is characterized by hyperandrogenemia, obesity, and oligo- or anovulation. In addition, women with PCOS are often obese, with insulin resistance, hyperlipidemia, and elevated blood pressure. The cardiometabolic consequences for the male offspring of maternal hyperandrogenemia are unclear. The present studies tested the hypothesis that male offspring of a rat model of PCOS would develop cardiometabolic disease as adults. Female Sprague-Dawley rats (hyperandrogenemic females (HAF)) were implanted with dihydrotestosterone or placebo pellets (controls) at 4 weeks of age, and were mated at 10-12 weeks and allowed to lactate their offspring after birth. Body weights in male HAF offspring were lower at birth than in controls until postnatal day 4, but body weights remained similar between male control and HAF offspring from 2 to 8 weeks of age. However, at 16 weeks of age, body weight was lower in HAF male offspring, but there were no differences in fat mass or lean mass factored for body weight in HAF males, compared to controls. Plasma total cholesterol and HDL and proteinuria were higher and nitrate/nitrite excretion was lower in male HAF offspring than in controls. Baseline blood pressure was similar between HAF male offspring and controls, but HAF offspring had an exaggerated pressor response to angiotensin II infusion. These data suggest that adult sons of PCOS mothers may be at increased risk of cardiometabolic disease.

Imatinib improves insulin resistance and inhibits injury-induced neointimal hyperplasia in high fat diet-fed mice

Imatinib, a PDGF receptor tyrosine kinase inhibitor, has been shown to suppress intimal hyperplasia in different animal models under normal metabolic milieu, diabetic, and/or hypercholesterolemic conditions. However, the impact of imatinib treatment on injury-induced neointimal hyperplasia has not yet been investigated in the setting of insulin resistance without frank diabetes. Using a mouse model of high fat diet (HFD)-induced insulin resistance and guidewire-induced arterial injury, the present study demonstrates that intraperitoneal administration of imatinib (25 mg/kg/day) for ~3 weeks resulted in a marked attenuation of neointimal hyperplasia (intima/media ratio) by ~78% (n = 6-9 per group; P < 0.05). Imatinib treatment also led to significant improvements in key metabolic parameters. In particular, imatinib improved insulin resistance and glucose tolerance, as revealed by complete inhibition of HFD-induced increase in HOMA-IR index and AUC_IPGTT, respectively. In addition, imatinib treatment led to diminutions in HFD-induced increases in plasma total cholesterol and triglycerides by ~73% and ~59%, respectively. Furthermore, imatinib decreased HFD-induced increase in visceral fat accumulation by ~51% (as determined by epididymal white adipose tissue weight). Importantly, imatinib treatment in HFD-fed mice enhanced plasma levels of high-molecular-weight adiponectin by ~2-fold without affecting total adiponectin. However, there were no significant changes in mean arterial pressure in insulin-resistant state or after imatinib exposure, as measured by tail-cuff method. Together, the present findings suggest that targeting PDGF receptor tyrosine kinase using imatinib may provide a realistic treatment option to prevent injury-induced neointimal hyperplasia and diet-induced insulin resistance in obesity.

Abstract P209: Androgen Receptor Antagonist, Bicalutamide, And Androgen Receptor Degradation Enhancer, Asc-j9, Decrease Blood Pressure Similarly In Male Spontaneously-hypertensive Rats

Background: Men are at greater risk for cardiovascular disease (CVD) than women until after menopause. For this reason, androgens have been implicated as playing a role in CVD in men. We have studied the role that androgens play in mediating the hypertension (HT) in spontaneously-hypertensive rats (SHRs), and found that blood pressure (BP) is decreased with castration and increased with testosterone supplements. In addition, we found that androgen receptor (AR) antagonists reduce BP, but blockers of the conversion of testosterone to dihydrotestosterone have no effect on BP, suggesting that testosterone alone is capable of mediating HT in male SHR. Testosterone is known to induce genomic and non-genomic effects via binding to nuclear AR or via independent mechanisms caused by membrane-bound AR. It is unclear whether or not membrane-bound AR play a role in mediating HT in male SHRs. In the present study we tested the hypothesis that only nuclear AR, not membrane-bound AR, mediate the HT in male SHR.

Methods: Male SHR (aged 13 months; n = 5 - 6 rats/group) were implanted with radiotelemeters, and after 2 weeks recovery, mean arterial pressure (MAP) was measured for 4 days (baseline). Then rats were given vehicle (dimethylacetamide, DMA, 1 ml/kg, s.c.); bicalutamide (BICA, nuclear AR antagonist; 5 mg/k/d, s.c.); or Asc-j9 (AR degradation enhancer, 50 mg/kg/d, s.c.) for 8 days while measuring their MAP. Asc-j9 degrades both nuclear and membrane-bound AR.

Results: Both BICA and Asc-j9 reduced MAP in male SHRs (BICA: 171 ± 2 to 151 ± 1 mmHg, p < 0.05; Asc-j9: 172 ± 3 to 148 ± 2 mmHg, p < 0.05.). DMA vehicle also reduced MAP (176 ± 5 to 161 ± 4 mmHg, p < 0.05). The decrease in the BICA and Asc-j9 groups was significantly different than the DMA group.

Conclusion: In summary, AR degradation enhancer, that degrades both membrane-bound and nuclear AR, reduced MAP to similar level as nuclear AR antagonist in male SHR, suggesting that it is the nuclear AR that plays a greater role in mediating chronic BP control in male SHR. It is likely that membrane-bound AR may mediate more acute effects of androgen function independent of the BP.

Pregnancy Protects Hyperandrogenemic Female Rats From Postmenopausal Hypertension

Polycystic ovary syndrome, the most common endocrine disorder in women of reproductive age, is characterized by hyperandrogenemia, obesity, insulin resistance, and elevated blood pressure. However, few studies have focused on the consequences of pregnancy on postmenopausal cardiovascular disease and hypertension in polycystic ovary syndrome women. In hyperandrogenemic female (HAF) rats, the hypothesis was tested that previous pregnancy protects against age-related hypertension. Rats were implanted with dihydrotestosterone (7.5 mg/90 days, beginning at 4 weeks and continued throughout life) or placebo pellets (controls), became pregnant at 10 to 15 weeks, and pups were weaned at postnatal day 21. Dams and virgins were then aged to 10 months (still estrous cycling) or 16 months (postcycling). Although numbers of offspring per litter were similar for HAF and control dams, birth weights were lower in HAF offspring. At 10 months of age, there were no differences in blood pressure, proteinuria, nitrate/nitrite excretion, or body composition in previously pregnant HAF versus virgin HAF. However, by 16 months of age, despite no differences in dihydrotestosterone, fat mass/or lean mass/body weight, previously pregnant HAF had significantly lower blood pressure and proteinuria, higher nitrate/nitrite excretion, with increased intrarenal mRNA expression of endothelin B receptor and eNOS (endothelial nitric oxide synthase), and decreased ACE (angiotensin-converting enzyme), AT1aR (angiotensin 1a receptor), and endothelin A receptor than virgin HAF. Thus, pregnancy protects HAF rats against age-related hypertension, and the mechanism(s) may be due to differential regulation of the nitric oxide, endothelin, and renin-angiotensin systems. These data suggest that polycystic ovary syndrome women who have experienced uncomplicated pregnancy may be protected from postmenopausal hypertension.

Abstract 018: Female Offspring of Polycystic Ovary Syndrome Rat Model Exhibit Insulin Resistance and Tendency Toward Increased Blood Pressure With Aging

Background: Polycystic ovary syndrome (PCOS) is associated with metabolic dysfunction and elevated blood pressure (BP). Whether daughters born to PCOS mothers exhibit a PCOS phenotype is controversial. In addition, whether daughters of PCOS women develop metabolic dysfunction and elevated BP with aging has not been reported.

Objectives: The present study tested the hypothesis that aging causes an increase in MAP and metabolic dysfunction in female offspring of PCOS rats (F1 DHT ) along with changes in matrix metalloproteinase-9 (MMP-9) and transforming growth factor-β (TGF-β).

Methods: PCOS was induced in SD females by implantation of 5α-dihydrotestosterone pellets (DHT; 7.5 mg/90 days, sc) starting at 4 wks of age. Rats were mated with SD males, and allowed to deliver and lactate. F1 DHT were left untreated and were studied at 14-16 wks or 16-18 mos of age. Control dams were implanted with placebo pellets sc, allowed to mate, deliver and suckle their offspring (F1 PL ).

Results: MAP (radiotelemetry) in 14-16 wk F1 DHT females was not different from F1 PL, nor did they exhibit other PCOS characteristics. With aging, F1 DHT rats showed a strong tendency for increased MAP compared to F1 PL (107 ± 4 versus 93 ± 1 mmHg; p = 0.07 (n=2-4)). Plasma MMP-9 and TGF- β1, 2 and 3 were not different between groups. Fasting blood glucose was not different between groups (91 ± 2.6 vs 90 ± 1.6 mg/dl), but F1 DHT rats showed significant hyperinsulinemia (0.9 ± 0.05 vs 0.78 ± 0.03 ng/ml, p ≤ 0.05) and insulin resistance (increased HOMA-IR index; 3.3 ± 0.2 vs 2.8 ± 0.1, p ≤ 0.05, (n = 5-6)). Lean mass (248.3 ± 5.5 vs 241.2 ± 2.5 g), fat mass (38.7 ± 4.8 vs 39.7 ± 2.2 g) and total water (185.8 ± 4.8 vs 179.9 ± 3 g) by Echo MRI, in addition to body weight (310.7 ± 7.7 vs 298.1 ± 4.6 g ; (n = 6-8)) were also not different between groups.

Conclusion: MAP in aging female offspring of PCOS rat model tends to be increased along with hyperinsulinemia and insulin resistance with no changes in fasting glucose, lean/fat mass, body weight, MMP9 or TGF-β. The data suggest that women whose mothers had PCOS may be at increased risk for hypertension and metabolic dysfunction with aging, although the mechanisms for the hypertension are not clear.

Comparison of the effects of sulforaphane and pioglitazone on insulin resistance and associated dyslipidemia, hepatosteatosis, and endothelial dysfunction in fructose-fed rats

The purpose of this work was to compare the influences of sulforaphane (SFN) to those of the standard insulin sensitizer pioglitazone (PIO) on high fructose diet (HFrD)-induced insulin resistance, dyslipidemia, hepatosteatosis, and vascular dysfunction in rats. Male Sprague Dawley rats (150-200 g) were fed on a standard diet (control) or a high fructose diet (HFrD, 60% w/w fructose) for 60 days. From day 16, two subgroups of HFrD-fed rats received either SFN (0.5 mg/kg/day, orally) or PIO (5 mg/kg/day, orally) along with HFrD until the end of the experiment. Fructose-fed rats showed significant decreases in food intake, body weight and feeding efficiency; effects that were not altered by either treatment. Data from insulin tolerance test (ITT), oral glucose tolerance test (OGTT), and HOMA-IR and HOMA-β indices demonstrated impaired insulin sensitivity and glucose utilization in HFrD-fed rats. SFN and PIO treatments significantly reduced OGTT_AUC (Glass's Delta values = 1.12 and 0.84, respectively), decreased ITT_AUC (Glass's Delta values = 1.05 and 0.71, respectively), significantly diminished HOMA-IR index (by 55.6% and 77.6%, respectively), and increased HOMA-β value (by 1.8 and 1.3 fold, respectively) compared to the HFrD rats. Moreover, SFN and PIO ameliorated hepatic oxidative stress and reduced serum levels of C-reactive protein and lactate dehydrogenase in HFrD-fed rats. Furthermore, SFN and PIO administrations improved insulin resistance-associated heaptosteatosis and enhanced vascular responsiveness to acetylcholine-induced relaxations. However, only SFN was able to enhance serum HDL-C levels in HFrD group. These finding suggests that SFN elicited insulin-sensitizing, hepatoprotective, and vasculoprotective effects in HFrD insulin-resistant rats that were comparable to those exerted by PIO.

Alcohol-induced ketonemia is associated with lowering of blood glucose, downregulation of gluconeogenic genes, and depletion of hepatic glycogen in type 2 diabetic db/db mice

Alcoholic ketoacidosis and diabetic ketoacidosis are life-threatening complications that share the characteristic features of high anion gap metabolic acidosis. Ketoacidosis is attributed in part to the massive release of ketone bodies (e.g., β-hydroxybutyrate; βOHB) from the liver into the systemic circulation. To date, the impact of ethanol consumption on systemic ketone concentration, glycemic control, and hepatic gluconeogenesis and glycogenesis remains largely unknown, especially in the context of type 2 diabetes. In the present study, ethanol intake (36% ethanol- and 36% fat-derived calories) by type 2 diabetic db/db mice for 9 days resulted in significant decreases in weight gain (∼19.5% ↓) and caloric intake (∼30% ↓). This was accompanied by a transition from macrovesicular-to-microvesicular hepatic steatosis with a modest increase in hepatic TG (∼37% ↑). Importantly, ethanol increased systemic βOHB concentration (∼8-fold ↑) with significant decreases in blood glucose (∼4-fold ↓) and plasma insulin and HOMA-IR index (∼3-fold ↓). In addition, ethanol enhanced hepatic βOHB content (∼5-fold ↑) and hmgcs2 mRNA expression (∼3.7-fold ↑), downregulated key gluconeogenic mRNAs (e.g., Pcx, Pck1, and G6pc), and depleted hepatic glycogen (∼4-fold ↓). Furthermore, ethanol intake led to significant decreases in the mRNA/protein expression and allosteric activation of glycogen synthase (GS) in liver tissues regardless of changes in the phosphorylation of GS, GSK-3β, or Akt. Together, our findings suggest that ethanol-induced ketonemia may occur in concomitance with significant lowering of blood glucose concentration, which may be attributed to suppression of gluconeogenesis in the setting of glycogen depletion in type 2 diabetes.

Sulforaphane improves leptin responsiveness in high-fat high-sucrose diet-fed obese mice

Diet-induced obesity (DIO) is commonly associated with hyperleptinemia and leptin resistance. Leptin acts centrally to inhibit food intake and increase energy expenditure, thereby preventing body weight gain. Resistance to the biological effects of leptin represents a major obstacle in utilizing exogenously administered leptin as a treatment option for obesity. Of importance, recent studies demonstrate that naturally occurring compounds improve leptin sensitivity in DIO mice, as revealed by anorectic and body weight-lowering effects. To date, the role of sulforaphane (SFN, an isothiocyanate derived from cruciferous vegetables) on leptin responsiveness has not been examined, in spite of its known beneficial effects toward lowering body weight gain in DIO. In the present study, we determined the extent to which SFN regulates leptin responsiveness in high-fat high-sucrose (HFHS) diet-fed obese mice. SFN treatment (0.5 mg/kg/day, s.c.) for 23 days in HFHS-fed mice improved the responsiveness to intraperitoneally-injected leptin by promoting significant decreases in cumulative food intake and body weight gain. A single leptin injection (2 mg/kg; i.p.) resulted in significant decreases in food intake at 24 h and 38 h time points. In addition, a triple leptin injection (1 mg/kg/day, 3 days; i.p.) led to significant decreases in food intake at 14 h, 24 h, 38 h, 48 h, and 62 h time points. Furthermore, single and triple leptin injections prevented body weight gain at 38 h and 62 h time points, respectively. The present findings suggest that intervention with SFN, a naturally occurring isothiocyanate, has the potential to improve leptin responsiveness in DIO.

AdipoRon, an adiponectin receptor agonist, attenuates PDGF-induced VSMC proliferation through inhibition of mTOR signaling independent of AMPK: Implications toward suppression of neointimal hyperplasia

Hypoadiponectinemia is associated with an increased risk of coronary artery disease. Although adiponectin replenishment mitigates neointimal hyperplasia and atherosclerosis in mouse models, adiponectin therapy has been hampered in a clinical setting due to its large molecular size. Recent studies demonstrate that AdipoRon (a small-molecule adiponectin receptor agonist) improves glycemic control in type 2 diabetic mice and attenuates postischemic cardiac injury in adiponectin-deficient mice, in part, through activation of AMP-activated protein kinase (AMPK). To date, it remains unknown as to whether AdipoRon regulates vascular smooth muscle cell (VSMC) proliferation, which plays a major role in neointima formation. In the present study, oral administration of AdipoRon (50mg/kg) in C57BL/6J mice significantly diminished arterial injury-induced neointima formation by ∼57%. Under in vitro conditions, AdipoRon treatment led to significant inhibition of platelet-derived growth factor (PDGF)-induced VSMC proliferation, DNA synthesis, and cyclin D1 expression. While AdipoRon induced a rapid and sustained activation of AMPK, it also diminished basal and PDGF-induced phosphorylation of mTOR and its downstream targets, including p70S6K/S6 and 4E-BP1. However, siRNA-mediated AMPK downregulation showed persistent inhibition of p70S6K/S6 and 4E-BP1 phosphorylation, indicating AMPK-independent effects for AdipoRon inhibition of mTOR signaling. In addition, AdipoRon treatment resulted in a sustained and transient decrease in PDGF-induced phosphorylation of Akt and ERK, respectively. Furthermore, PDGF receptor-β tyrosine phosphorylation, which controls the phosphorylation state of Akt and ERK, was diminished upon AdipoRon treatment. Together, the present findings suggest that orally-administered AdipoRon has the potential to limit restenosis after angioplasty by targeting mTOR signaling independent of AMPK activation.

Sulforaphane inhibits platelet-derived growth factor-induced vascular smooth muscle cell proliferation by targeting mTOR/p70S6kinase signaling independent of Nrf2 activation

Activation of nuclear factor erythroid 2-related factor 2 (Nrf2, a transcription factor) and/or inhibition of mammalian target of rapamycin (mTOR) are implicated in the suppression of vascular smooth muscle cell (VSMC) proliferation. The present study has examined the likely regulatory effects of sulforaphane (SFN, an antioxidant) on Nrf2 activation and platelet-derived growth factor (PDGF)-induced mTOR signaling in VSMCs. Using human aortic VSMCs, nuclear extraction and siRNA-mediated downregulation studies were performed to determine the role of Nrf2 on SFN regulation of PDGF-induced proliferative signaling. Immunoprecipitation and/or immunoblot studies were carried out to determine how SFN regulates PDGF-induced mTOR/p70S6K/S6 versus ERK and Akt signaling. Immunohistochemical analysis was performed to determine SFN regulation of S6 phosphorylation in the injured mouse femoral artery. SFN (5μM) inhibits PDGF-induced activation of mTOR without affecting mTOR association with raptor in VSMCs. While SFN inhibits PDGF-induced phosphorylation of p70S6K and 4E-BP1 (downstream targets of mTOR), it does not affect ERK or Akt phosphorylation. In addition, SFN diminishes exaggerated phosphorylation of S6 ribosomal protein (a downstream target of p70S6K) in VSMCs in vitro and in the neointimal layer of injured artery in vivo. Although SFN promotes Nrf2 accumulation to upregulate cytoprotective genes (e.g., heme oxygenase-1 and thioredoxin-1), downregulation of endogenous Nrf2 by target-specific siRNA reveals an Nrf2-independent effect for SFN-mediated inhibition of mTOR/p70S6K/S6 signaling and suppression of VSMC proliferation. Strategies that utilize local delivery of SFN at the lesion site may limit restenosis after angioplasty by targeting mTOR/p70S6K/S6 axis in VSMCs independent of Nrf2 activation.

Comparative evaluation of anti-inflammatory properties of thymoquinone and curcumin using an asthmatic murine model

This study was designed to compare the inhibitory effects of thymoquinone (TQ) and curcumin (CMN) on the biological changes associating asthma. TQ appeared to exhibit greater inhibitory effects on the aggregation of inflammatory cells in bronchoalveolar lavage (BAL) fluid and in lung tissues. We also measured the effects of the two agents on serum IgE and the changes in the mRNA levels of inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1). Serum IgE was significantly decreased by TQ and CMN with TQ being more potent. Also, TQ showed superior inhibitory effects on iNOS and TGF-β1. Meanwhile, CMN was more potent in inhibiting mRNA expression of TNF-α. These results suggest that TQ is more potent in inhibiting the inflammatory changes associating asthma. On the other hand, CMN was a less potent inhibitor of all measured parameters, despite its superior inhibitory effect on TNF-α mRNA levels.