Inflammation is a key factor in the development of heart failure (HF), with interleukin-12 (IL-12) and interleukin-23 (IL-23) acting as significant pro-inflammatory cytokines, both of which are simultaneously reduced by inhibiting IL-12β. This study utilized IL-12β knockout (KO) mice to investigate whether genetically inhibiting IL-12β could lessen transverse aortic constriction (TAC)-induced cardiac inflammation, hypertrophy, and dysfunction, as well as associated lung remodeling. We found that IL-12β KO significantly improved TAC-induced cardiac dysfunction in both male and female mice, evidenced by better left ventricular (LV) ejection fraction and fractional shortening. Additionally, IL-12β KO substantially reduced the TAC-induced increases in the weight of the LV, left atrium, lung, and right ventricle (RV), and their ratios to body weight or tibial length in both sexes. Furthermore, IL-12β KO markedly attenuated TAC-induced LV leukocyte infiltration, cardiomyocyte hypertrophy, fibrosis, and subsequent lung inflammation and remodeling. Bulk LV RNA sequencing demonstrated that IL-12β KO also mitigated TAC-induced changes in LV gene profiles linked to inflammation and fibrosis. We also found that IL-12β KO significantly reduced TAC-induced LV accumulation of various immune cell subsets, activation of CD4+ and CD8+ T cells, and the percentage of central memory CD4+ and CD8+ T cells within the cardiac drainage lymph nodes. Moreover, IL-12β KO mice exhibited a significant reduction in IFNγ+CD8+ and CXCR3+CD8+ T cells in the drainage lymph nodes compared to wild-type mice after TAC. Finally, IL-12β KO and IL-12β blocking antibody significantly decreased TAC-induced LV production of reactive oxygen species (ROS) and the expression of 3-nitrotyrosine (3-NT) and 4-hydroxynonenal (4-HNE). Collectively, these findings underscore the critical role of IL-12β in systolic overload-induced LV inflammation and HF, likely through mediating cardiac immune cell accumulation, oxidative stress, and fibrosis.

Obesity rates have increased dramatically during the past four decades, and these increases have occurred in children and adolescents, as well as in adults at reproductive age. Currently, 40.3

BACKGROUND:Cardiovascular disease remains the leading cause of death worldwide, with coronary artery disease being the primary contributor. Our recent studies suggest that activation of LepRs (leptin receptors) in the brain can improve cardiac function after myocardial infarction. However, the mechanism by which this cardioprotective effect is transmitted from the brain to the heart remains unclear. We hypothesize that brain LepR activation stimulates brown adipose tissue (BAT) to secrete extracellular vesicles (EVs) enriched with cardioprotective factors. These EVs may safeguard the heart by modulating cardiac mitochondrial function and collagen deposition.METHODS:Sprague-Dawley rats with BAT intact, BAT ablation, or BAT sympathetic denervation were implanted with an intracerebroventricular cannula for continuous leptin or vehicle delivery over 28 days after cardiac ischemia-reperfusion injury. Cardiac function was assessed weekly via echocardiography and by ventricular catheterization at the end of the protocol. EVs were isolated from BAT for analysis. Rab27a (Ras-related protein Rab-27A), a protein required for EV release, was knocked down using adeno-associated virus, and EV tracking was conducted using a double fluorescent reporter mouse model.RESULTS:Our findings indicate that BAT ablation or BAT sympathetic denervation diminishes the cardioprotective effects of brain LepR activation. We also observed an increased concentration of EVs within the BAT of rats treated with intracerebroventricular leptin compared with vehicle-treated controls, an effect abolished by BAT denervation. Furthermore, knockdown of Rab27a in BAT reduced the cardioprotective benefits of brain LepR activation. MicroRNA miR-29c-3p was identified as a cargo of leptin-stimulated BAT-derived EVs and appears to play a key role in mitigating cardiac fibrosis after ischemia-reperfusion injury in leptin-treated animals.CONCLUSIONS:Activation of LepR in the brain protects the heart after ischemia-reperfusion injury via sympathetic-mediated BAT-derived EVs enriched with miR-29c-3p.

Acute myocardial infarction (MI) is a leading cause of death worldwide, accounting for >1 million deaths/year in the United States alone. Although parental obesity is a risk factor for offspring cardiovascular diseases, the impact of parental obesity on offspring outcomes after MI is unknown. This study examined if non-obese male and female offspring from obese Sprague-Dawley rat parents fed a high-fat diet (HFD-Offs, n = 11-19/sex) are at greater risk of death and worse cardiac dysfunction after MI, compared with offspring from lean parents fed a normal diet (ND-Offs, n = 12-15/sex). All offspring were fed ND from weaning and subjected to left descending coronary artery ligation at 12 wk of age to induce MI. Survival rate 24 h post-MI was examined, and cardiac function was measured by echocardiography and intraventricular catheterization with a Millar catheter on day 7 post-MI. Compared with ND-Offs, male and female HFD-Offs exhibited increased ventricular fibrillation and reduced survival post-MI (male: 37% vs. 80% and female: 55% vs. 83% for HFD-Offs and ND-Offs, respectively). In surviving rats, systolic dysfunction was more pronounced in male and female HFD-Offs compared with ND-Offs at day 7 post-MI, despite similar infarct size in all groups. We also found reductions in baseline O2 consumption rate and pyruvate-supported mitochondrial respiration, as well as increased mitochondria-derived superoxide production in cardiac fibers from HFD-Offs. Thus, parental obesity is associated with an increased 24-h mortality rate in their offspring after induction of MI and worse systolic function even when the offspring are fed a healthy diet after weaning and remain lean.NEW & NOTEWORTHY A major new finding of this study is that parental obesity markedly reduces survival rate and exacerbates cardiac dysfunction after myocardial infarction in their offspring, and this effect is independent of offspring sex.

Myocardial infarction (MI) causes a robust inflammatory response, which is necessary for remodeling and scar formation of the infarcted left ventricle (LV). However, this can lead to chronic systemic inflammation and persistent autoimmune responses. In this study, we analyzed sex differences in the inflammatory autoimmune response to chronic MI. MI was induced by permanent left coronary artery ligation in adult male and female C57BL/6J mice for one, four, and eight weeks. Both sexes exhibited similar declines in LV function. Females had higher levels of total immune cells and T cells in the infarct and remote area at D7 post-MI, and B cells at D56. MI increased levels of pro-inflammatory cytokines (Il1b, Il6, Tnf, Ccl2, Ifng, Il18) in the LV infarct that peaked at one week, which was exaggerated in females for Il6, Ifng, and Il10. In the remote LV, females had higher levels of Il6, Tnf, Ccl2, and Il18. MI increased spleen mass in females only, and splenic cytokines were higher in females at several time points, including Il1b, Il12a, Il10, Ifng, Il18, Ccl2, and Il4. IgG and IgM deposition in the LV infarct increased over time in both sexes, but more so in females. In the remote area, both sexes had increased IgG and IgM at eight weeks. Plasma IgM was higher in females at one, four, and eight weeks post-MI compared with males. Plasma IgG and IgM autoantibodies were detected in males and females after MI, but the number of autoantibodies displaying reactivity to autoantigens was much higher in females, particularly at week 8. In summary, MI leads to the development of systemic and myocardial autoimmune activation, which is more pronounced in females.

Our study shows that the combination of diabetes (DM) and hypertension (HTN) promoted renal dysfunction, albuminuria, and mitochondrial dysfunction, whereas DM or HTN alone caused only mild kidney injury. Treatment with the specific mitochondria-targeted antioxidant Mito-TEMPO greatly ameliorated renal injury in rats with both DM + HTN. These results suggest that targeting mitochondria-derived ROS may be a potential therapeutic strategy to attenuate the development of kidney injury induced by the combination of DM and HTN.

Myocardial infarction (MI) is caused by ischemic injury to the left ventricle (LV), leading to an acute inflammatory response, scar formation, and loss of LV function. The role of the antibody-mediated response and autoimmune (AI) development during MI is not well understood. AI disease is highly prevalent in females, which increases risk of MI and worsens MI outcomes. Thus, we hypothesized that females would exhibit increased susceptibility to MI-induced development of AI signatures, including B cell activation and autoantibody (AAB) production. Permanent MI was induced by left coronary artery ligation in adult male and female C57BL/6J mice, which were followed for 7, 28, or 56 days, using no MI (D0) as controls. LV function was tracked using echocardiography (VEVO 3100). LV infarct cytokines were measured by qPCR. LV infarct and blood leukocytes were measured by flow cytometry. LV IgG and IgM antibody deposition was measured by immunofluorescence. Plasma AABs (IgG and IgM subclasses) were measured with an autoantigen (AAN) microarray (128 AANs). In both sexes, MI led to progressive LV hypertrophy, increased end-diastolic diameter and volume, anterior/posterior wall thinning, and decreased ejection fraction. Survival was significantly higher in females for each time point (100% vs 50% at D7, 83% vs 57% at D28, 94% vs 39% at D56). MI increased spleen mass/tibia length in D7, 28, and 56 females, but decreased spleen mass in D28 and 56 males. LV inflammatory cytokines (IL-1β, IL-6, IL-18, IFN-γ, TNF, CCL2, IL-10) were increased at D7. In both sexes, IL-6 and IL-18 remained elevated at D28 and 56. Blood and LV myeloid cells were increased at D7 in both sexes, while B and T cells were decreased. At D28, myeloid cells returned to D0 levels; LV activated B cells (CD80+) and T cells (CD3+) were increased. At D56, only B cells remained elevated in the LV. IgG deposition was increased in the female LV at D7 (14.1±1.2% area fraction vs 6.3±1.5% D0) and further at D28 (40.4±3.6%), but only at D28 in males (20.4±4.0% vs 3.1±0.7% D0). Both sexes exhibited increased LV IgM at D7 and 28, however, the IgM response at D7 was higher in females (21.1±2.8% vs 8.3±1.6% in males). In plasma, MI increased AABs against several AANs (p<0.05 vs D0). Compared to D0, D7 females had elevated IgG AABs 1 AAN (dsDNA, a classical AI marker) vs 0 for males, and elevated IgM AABs against 4 different AANs versus 1 for males. D28 females had elevated IgG AABs against 1 AAN vs 4 for males, and elevated IgM AABs against 5 AANs vs 0 in males. D56 females had elevated IgG AABs against 34 AANs vs 9 in males, and elevated IgM AABs against 30 AANs versus 1 for males. For both IgG and IgM AABs in D56 females, several were against AANs highly expressed in the heart, including ACE2, mitochondrion, and myosin. Furthermore, D56 female IgM AABs were increased against IL-6 (9.8±0.8 fold change), which as mentioned earlier, remained elevated in the LV at all post-MI time points. In summary, MI promotes development of AI signatures, including LV B and T cell activation, IgG and IgM antibody deposition, and increased circulating AABs, which is exacerbated in females. NHLBI R01 HL166737 (Mouton), AHA Career Development Award CDA856365 (Mouton), NIH/NHLBI R00 HL146888 (Taylor), U54 HL169191 (Taylor), NIGMS P20 GM104357 (Hall), P30 GM149404 (Hall), U54 GM115428 (Hall), NHLBI R01 HL1630376 (da Silva), NIDDK R01 DK121411 (do Carmo), AHA Postdoctoral Fellowship 835218 (Omoto). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Recent evidence from our lab and others suggests that metabolic reprogramming of immune cells drives changes in immune cell phenotypes along the inflammatory-to-reparative spectrum and plays a critical role in mediating the inflammatory responses to cardiac injury (e.g. hypertension, myocardial infarction). However, the factors that drive metabolic reprogramming in immune cells are not fully understood. Extracellular vesicles (EVs) are recognized for their ability to transfer cargo such as microRNAs from remote sites to influence cardiac remodeling. Furthermore, conditions such as obesity and metabolic syndrome, which are implicated in the majority of cardiovascular disease (CVD) cases, can skew production of EVs toward pro-inflammatory phenotypes. In this mini-review, we discuss the mechanisms by which EVs may influence immune cell metabolism during cardiac injury and factors associated with obesity and the metabolic syndrome that can disrupt normal EV function. We also discuss potential sources of cardio-protective and anti-inflammatory EVs, such as brown adipose tissue. Finally, we discuss implications for future therapeutics.

Although obesity is recognized as a risk factor for cardiorenal and metabolic diseases, the impact of parental obesity on the susceptibility of their offspring to renal injury at adulthood is unknown. We examined the impact of parental obesity on offspring kidney function, morphology, and markers of kidney damage after acute kidney injury (AKI). Offspring from normal (N) diet-fed C57BL/6J parents were fed either N (NN) or a high-fat (H) diet (NH) from weaning until adulthood. Offspring from obese H diet-fed parents were fed N (HN) or H diet (HH) after weaning. All offspring groups were submitted to bilateral AKI by clamping the left and right renal pedicles for 30 min. Compared with male NH and NN offspring from lean parents, male HH and HN offspring from obese parents exhibited higher kidney injury markers such as urinary, renal osteopontin, plasma creatinine, urinary albumin excretion, and neutrophil gelatinase-associated lipocalin (NGAL) levels, and worse histological injury score at 22 wk of age. Only albumin excretion and NGAL were elevated in female HH offspring from obese parents compared with lean and obese offspring from lean parents. We also found an increased mortality rate and worse kidney injury scores after AKI in male offspring from obese parents, regardless of the diet consumed after weaning. Female offspring were protected from major kidney injury after AKI. These results indicate that parental obesity leads to increased kidney injury in their offspring after ischemia-reperfusion in a sex-dependent manner, even when their offspring remain lean.NEW & NOTEWORTHY Offspring from obese parents are more susceptible to kidney injury and worse outcomes following an acute ischemia-reperfusion insult. Male, but not female, offspring from obese parents exhibit increased blood pressure early in life. Female offspring are partially protected against major kidney injury induced by ischemia-reperfusion.

The prevalence of obesity in women of reproductive age is increasing rapidly, and children from obese mothers are at higher risk of developing cardiovascular diseases in adulthood. Acute myocardial infarction (MI) is one of the leading causes of death worldwide with more than one million deaths per year in the U.S. alone. Using a model of parental obesity with male and female Sprague-Dawley rats fed a high fat diet (HFD) prior to mating, and dams maintained on the HFD during gestation and lactation, we found that male and female offspring from these obese parents have multiple metabolic abnormalities early in life (3 weeks old), and that male, but not female, offspring have impaired diastolic function associated with reduced cardiac SIRT3 expression and mitochondrial biogenesis. At 24 weeks of age, male offspring from obese parents exhibit increased blood pressure. To examine if offspring from obese parents are at greater risk of death and worse cardiac function after MI, male and female lean offspring fed a normal diet (ND) born from ND fed lean parents (ND-Offs, n=5-6/sex) and lean offspring fed ND born from HFD fed obese parents (HFD-Offs, n=6-11/sex) were submitted to a permanent left descending coronary artery ligation to induce MI at 12 weeks of age. Twenty-four-hour survival rate post-MI surgery was examined and cardiac function was measured by intraventricular catheterization with a Millar catheter on day 7 post-MI. Compared to ND-Offs, male and female HFD-Off born from obese HFD-fed parents exhibited reduced survival rate (male: 60% vs 100% and female: 55% vs. 83% for HFD-Offs and ND-Offs, respectively) and increased ventricular fibrillation post-MI. At day 7 post-MI, we observed reduced +dP/dtmax in male, but not female, HFD-Offs compared to ND-Offs (6,554±25 vs. 8,253±440 mmHg/sec in males and 7,962±557 vs. 7,668±890 mmHg/sec in females, for HFD-Offs and ND-Offs, respectively) despite similar infarct size in all groups (~40% of the total left ventricle circumference). We found no major differences in -dP/dtmin or tau (indices of diastolic function) between groups. Thus, parental obesity is associated with increased mortality rate in their offspring after induction of MI and worse systolic function in male, but not female, offspring even when offspring are fed a healthy diet after weaning and remain lean. NIDDK 1R01121411 (do Carmo), HL1630376 (da Silva/do Carmo), NIGMS P20GM104357 (Hall), P30GM149404 (Hall) and U54GM115428 (Hall). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Hypertension is the leading driver of cardiovascular diseases and premature death worldwide. Obesity/overweight accounts for 65%–78% of the risk for primary (essential) hypertension and >70% of end-stage kidney disease via hypertension and diabetes mellitus. Because of the rising prevalence of obesity, the health care and economic burdens of hypertension, diabetes mellitus, and chronic kidney disease are also increasing in most countries. Increased renal sodium reabsorption plays an important role in initiating obesity–hypertension. The mediators of abnormal kidney function during development of obesity–hypertension include renal compression by fat in and around the kidneys, activation of the renin–angiotensin–aldosterone system, and increased sympathetic nervous system activity. Additional factors such as hyperglycemia, dyslipidemia, immune cell activation, and inflammation interact with hypertension to cause target organ damage and to exacerbate hypertension. Lifestyle interventions represent the cornerstone for treating obesity. However, high rates of recidivism, prolonged obesity, and progressive target organ damage often lead to treatment-resistant hypertension, requiring multiple antihypertensive drugs and medications for other risk factors including dyslipidemia, insulin resistance, diabetes, and inflammation. Although adequate control of this constellation of disorders is challenging, progress is being made in developing more effective therapies for obesity and accompanying cardiorenal and metabolic disorders.

Maternal obesity increases the risk of preterm delivery which may result in rapid transition of their offspring from a relatively hypoxemic environment to normal or elevated oxygen environment, especially if the baby receives oxygen therapy. This exposure of premature infants to increased oxygen levels could induce oxidative stress and detrimental effects on organ development and maturation. Previous studies have shown that early-life exposure to high oxygen levels (hyperoxia) induces cardiovascular disease later in life. In the present study, we tested the hypothesis that neonatal exposure to hyperoxia (HO) leads to elevated blood pressure (BP) at adulthood in offspring from lean mothers and exacerbates the adverse impact of maternal obesity on offspring BP regulation. Male (n=5-7) and female (n=5-7) offspring from lean and high fat diet-fed obese mothers were exposed to room air (21% O2) or hyperoxia (80% O2) between postnatal (P) days P3-P10, and then returned to room air. The rats were provided food and water ad libitum and followed until 12-13 weeks of age when telemetry probes were implanted to measure BP and heart rate (HR) 24-hrs/day. After 10 days of recovery from surgery, BP and HR were measured for 5 consecutive days. Contrary to our hypothesis, neonatal HO was associated with lower BP compared to control offspring from lean mothers (males: 111±1 vs. 105±1 mmHg and females: 108±0.4 vs. 102±0.4 mmHg). Neonatal HO exposure was also associated with similar reductions in BP in hypertensive obese offspring from obese mothers (males: 123±1 vs. 117±1 mmHg and females: 116±1 vs. 113±1 mmHg). Offspring exposed to neonatal HO showed a tendency for reduced HR compared to lean and obese offspring not submitted to HO with significant reduction observed in obese female offspring from obese mothers (393±3 vs. 379±2 bpm). These results suggest that exposure to hyperoxia in early postnatal life is not associated with elevated BP in adulthood and it does not exacerbate the hypertensive effects of maternal obesity on offspring BP regulation. NIDDK 1R01121411, NIGMS P20GM104357 and NIGMS U54GM115428 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

During myocardial infarction (MI), macrophages (MØ) infiltrate the ischemic left ventricle (LV) and mediate cardiac remodeling and healing. Metabolic shifts in the LV and infiltrating MØs is a hallmark of the response to injury. Glutamine is a major metabolic fuel for cardiac muscle and MØs. However, the role of GLN metabolism in the remodeling heart after MI is not well understood. We used a model of permanent coronary artery ligation in adult male C57BL/6J mice to assess GLN metabolism in extracted cardiac MØs at post-MI days (D) 1, 3, and 7. Using untargeted metabolomics, we found time-dependent changes in metabolites related to GLN and glutamate (GLU) metabolism in cardiac MØs (p=6E-4). GLN levels were significantly increased at day 3, while GLU was decreased at day 7, and the GLN/GLU ratio was higher at both D3 and 7 compared to D1 post-MI. Using Seahorse extracellular flux analysis, GLN consumption in MØs was increased on D1 and 3. In the remote area of the heart (RA), genes for GLN-metabolizing enzymes (Glud1, Got1, Gpt1) were decreased at D3 and 7, indicating a loss of GLN metabolism. We then administered GLN (1 g/kg body weight, i.p.) daily post-MI for up to D3 or 7. Compared to vehicle, GLN administration increased ejection fraction at D3 (1.2-fold increase) and 7 post-MI (1.6-fold increase), and attenuated anterior and posterior wall thinning at D7 by 1.6-fold and 1.3-fold, respectively. GLN also restored expression of genes associated with GLN metabolism (Gls1, Glul, Got1, Gpt1, Glud1) in the RA, as well as glucose oxidation (Pdha1). GLN also restored Myh6 expression and attenuated Myh7 expression, indicating favorable expression of myosin heavy chains. However, GLN did not affect cardiac MØ phenotype, as assessed by flow cytometry and cytokine mRNA levels (Il1b, Tnf, Il6, Ccl2, Il18, and Il10). We then blocked GLN metabolism by administering BPTES (12.5 mg/kg daily i.p. in corn oil) to mice for 3 days post-MI. BPTES exacerbated anterior wall thinning (1.4-fold decrease) and further decreased EF (1.4-fold) after MI, and also increased expression of Myh7 in the RA. However, BPTES did not affect MØ phenotypes. In conclusion, dysregulation of GLN metabolism is a hallmark of post-MI cardiac remodeling, and enhancing GLN metabolism may improve cardiac function, but may not be effective for reducing MØ-mediated inflammation post-MI. Funding: NIDDK 1R01121411, P20GM104357, U54GM115428, AHA856365 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Transient receptor potential channel 6 (TRPC6) is a nonselective cation channel belonging to the TRP ion channel family and expressed in vascular smooth muscle cells. TRPC6 regulates calcium influx in response to vascular wall mechanical stretch. A previous study reported that TRPC6 is critical for the myogenic response of the middle cerebral artery (MCA). Impaired MCA myogenic response is implicated in cerebral blood flow dysfunction and may promote cognitive deficits. In this study, we investigated whether TRPC6 contributes to the MCA myogenic response at pressure range (from 40 to 180 mmHg) in 12-week-old male wild-type (WT) and whole-body TRPC6 knock-out (TRPC6 KO) mice (n=5-8). Cognitive function (spatial learning and reference memory) was examined at 22 weeks of age using the Morris water maze test. Myogenic response in MCA was similar in WT and TRPC6 KO mice when perfusion pressure was increased from 40 to 80 mmHg. At higher pressures (>120 mmHg), however, TRPC6 KO mice displayed significantly reduced myogenic response compared to WT mice (3 % less of myogenic tone in TRPC6 KO compared to WT) which was further exacerbated when perfusion pressure was increased to 180 mmHg (9 % less of myogenic tone in TRPC6 KO compared to WT). There were no significant differences in wall thickness, wall-to-lumen ratio, vascular distensibility, incremental distensibility, or elastic modulus curves in MCA between WT and TRPC6 KO mice. Compared to WT mice, TRPC6 KO mice displayed similar spatial learning curves after 4 days of training but showed significantly impaired reference memory (14±1 % vs 29±4 % in the target quadrant) and reduced frequency (1.0±0.3 vs 2.1±0.4 in the target area crossing) compared to WT. These findings suggest that TRPC6 deficiency impairs myogenic response at higher perfusion pressures and spatial memory, even at a young age. (AG050049 (F.F), AG057842 (F.F), AG079336 (F.F), NIDDK R00DK113280, R01DK121411, NIGMS P20GM104357 and NIGMS U54GM115428) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

We examined potential sex differences in appetite and blood pressure (BP) responses to melanocortin-4 receptor (MC4R) blockade in offspring from lean and obese parents. Offspring from normal (N) diet-fed parents were fed N (NN) or high-fat (H) diets (NH) from weaning until adulthood. Offspring from obese H diet-fed parents were also fed N (HN) or H diets (HH). Adult male and female offspring were implanted with BP telemetry probes and intracerebroventricular cannulas to infuse MC4R antagonist or vehicle. Infusion of the MC4R antagonist SHU-9119 (1 nmol/h) for 7 days caused larger increases in calorie intake and body weight in obese compared with lean offspring. In male offspring, HH and HN groups exhibited higher baseline BP compared with NN and NH, and HH showed a greater reduction in BP during SHU-9119 infusion. In female offspring, HH also showed higher baseline BP and greater reduction in BP during MC4R blockade. SHU-9119 reduced heart rate in all groups, but reductions were more pronounced in offspring from lean parents. Combined α and β-adrenergic blockade reduced BP more in male HH offspring compared with NN controls. Losartan reduced BP more in male NH, HN, and HH offspring compared with NN controls. Losartan and α- and β-adrenergic blockade reduced BP similarly in all female groups. These results suggest that endogenous MC4R activity contributes to elevated BP in obese offspring from obese parents. Our findings also indicate important sex differences in the mechanisms of BP control in male and female offspring of obese parents.

Ischemia/reperfusion (I/R)-induced acute kidney injury (AKI) is a major clinical problem without effective therapy and is a significant cause of morbidity and mortality during the perioperative period. The hallmarks of I/R-AKI include renal tubular cell injury and mitochondrial dysfunction. Transient receptor potential channel subfamily C member 6 (TRPC6), a non-selective cation channel that mediates the influx of calcium and other monovalent cations into cells, is widely expressed in the kidney, including proximal tubular cells. TRPC6 deficiency has been reported to be protective in chronic kidney diseases by reducing oxidative stress; however, its role in AKI is still controversial. In this study, we examined the role of TRPC6 during the early phase of renal injury in I/R-induced AKI. To reduce the severity and limit variability in kidney injury after I/R, we performed unilateral I/R surgery with 30 minutes of ischemia in the left kidney of 22-week-old male wild-type (WT) and whole-body TRPC6 knockout (TRPC6 KO) mice. Mitochondrial respiration rate and mitochondria-generated superoxide in the left kidney were examined 18 hours after I/R surgery by OROBOROS Oxygraph Respirometry. Serum creatinine and urinary neutrophil gelatinase-associated lipocalin (NGAL) concentration were determined in addition to histological evaluation by PAS staining in WT and TRPC6 KO mice. Our results show that the mitochondrial oxygen consumption rate was significantly higher in I/R kidneys from TRPC6 KO mice compared to WT (56.5±9.3 vs. 22.9±2.0 pmol/min/mg, n=5-6). Despite higher mitochondrial respiration, mitochondria-generated superoxide production was significantly lower in the kidney of TRPC6 KO mice. TRPC6 KO mice also exhibited significantly lower serum creatinine (0.26±0.02 vs. 0.37±0.08 mg/dL, n=7-10) and urinary NGAL levels (526.6±58.7 vs. 1313.5±192.0 ng/mL, n=6-10) than WT mice. Renal histology showed that I/R kidneys from TRPC6 KO mice have reduced tubular cell death in outer medulla areas and decreased tubular clots and inflammatory cell infiltration. These observations suggest that TRPC6 deficiency may be protective during the early phase of I/R-induced AKI by preserving mitochondrial respiration and attenuating mitochondria reactive oxygen species generation. Targeting TRPC6 and its downstream signaling pathways may provide new avenues for future I/R-induced AKI therapies. (NIDDK R00DK113280 and R01DK121411, NIGMS P20GM104357 and NIGMS U54GM115428) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Ischemic heart disease is the leading cause of death in the U.S. and worldwide. We recently demonstrated that infusion of leptin into the central nervous system (CNS) dramatically improves cardiac metabolism and function following ischemia/reperfusion (IR) injury. How the brain communicates with the heart during central leptin infusion to improve cardiac function after IR injury is still unknown. One potential mechanism may be via activation of brown adipose tissue (BAT), as central leptin administration has been shown to induce BAT-mediated thermogenesis. Furthermore, BAT has been proposed as an important source of extracellular vesicles (EVs) carrying bioactive molecules with cardioprotective effects. Thus, we investigated whether BAT contributes to the cardioprotective effect of central leptin infusion and the potential role of EVs in this protection. Male Sprague-Dawley rats (~8 weeks of age) were submitted to interscapular BAT ablation (iBATx) and instrumented with an intracerebroventricular (ICV) cannula in the brain lateral ventricle. After recovery and baseline assessment of cardiac function by echocardiography (ECHO), myocardial IR was induced by temporary (60 min) ligation of the left anterior descending coronary artery. Vehicle (saline, 0.5 μL/hr) or leptin (0.62 μg/hr) was infused chronically for 28 days starting 30 min after reperfusion using osmotic pumps implanted subcutaneously in the scapular region and connected to the ICV cannula. Cardiac function was assessed weekly by ECHO. Another set of animals with intact iBAT was treated with ICV leptin or vehicle for 2 weeks and had their iBAT collected for EVs isolation and quantification by differential ultracentrifugation and nanoparticle tracking analysis, respectively. Compared to vehicle-treated animals, ICV leptin infusion increases iBAT-derived EVs (5.6x109 vs 1.6 x109 particles/mg of tissue), and removal of iBAT prevent leptin’s CNS-mediated cardioprotective effects after IR injury as indicated by a lack of improvement in ejection fraction (26.9±2.5 vs 40.9±1.2%), stroke volume (154.6±15 vs 275.3±8μL) and global longitudinal strain (-7.4±1.1 vs -13.9±0.5%) at week 4 post-IR. These results suggest that the BAT plays an important role in mediating the cardioprotective effect of CNS leptin administration after I/R injury and that iBAT-derived EVs may be involved in delivering protective molecules to the heart during central leptin infusion. AHA 835218, NIGMS P20GM104357, NIDDK R00DK113280, R01DK121411 and P20GM104320 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Kidney disease is estimated to occur in 37 million people in the US, approximately 15% of the adult population. Obesity is a major driver of kidney disease via mechanisms that are still unclear, and pre-conception obesity in the parents may program kidney dysfunction and inflammation in their offspring. Using a model of parental obesity where male and female mice are fed high fat (H) diet prior to mating, with dams maintained on the H diet during gestation and lactation, we found that male offspring exhibit hypertension and initial signs of kidney injury in adulthood (24 weeks of age). We examined whether offspring from obese parents exhibit worse outcome after acute kidney injury (AKI), and whether this is associated with an immunometabolic shift in macrophages (Mɸ) toward glycolytic and pro-inflammatory phenotypes, as assessed by flow cytometry and Seahorse extracellular flux analysis to measure extracellular acidification rate (ECAR) as a measure of glycolysis. The following groups of male mice were submitted to bilateral renal AKI by clamping the left and right pedicles for 30 min: 1) lean offspring fed normal (N) diet born from N diet lean parents (NN, n=5); 2) obese offspring fed H diet born from N diet parents (NH, n=6); 3) lean offspring fed N diet born from H diet obese parents (HN, n=6); and 4) obese offspring fed H diet born from H diet obese parents (HH, n=7). Compared to NH and NN offspring from lean parents, HH and HN offspring from obese parents exhibited worse kidney dysfunction with higher urinary renal osteopontin (OPN) levels (93.8±8.7 and 73.7±16.6 vs. 213.8±24.0 and 151.1±24.6 μg/24h). We also found increased CD45+ Mɸ-like cells which play a role in initiating and maintaining kidney inflammation, as well as worse kidney injury score, increased tubular cell death, tubular blood clot, and glomerular tubularization in offspring from obese parents. Additionally, HH and HN offspring exhibited expansion of renal M1 Mɸ phenotype 4 days after AKI assessed by ECAR (glycolysis: 5.9±0.8 and 4.1±0.5 vs. 9.5±0.9 and 13.5±0.8 ΔmpH/min). Thus, parental obesity is associated with a shift towards M1 inflammatory Mɸ phenotype and increased risk of worse renal dysfunction in their offspring after AKI, even when offspring remain lean. NIDDK 1R01121411, NIGMS P20GM104357 and NIGMS U54GM115428) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Important adverse changes in cardiac energy metabolism occur after ischemia/reperfusion injury (I/R), contributing to the worsening of cardiac function and development of heart failure. We recently showed that leptin, via its actions on the central nervous system (CNS), improves left ventricular (LV) function in a model of heart failure induced by permanent ligation of the left anterior descending coronary artery (LAD). In the present study, we examined whether the CNS‐ effects of leptin protect against myocardial I/R injury, and if chronic intracerebroventricular (ICV) leptin infusion improves cardiac substrate utilization, assessed by markers of myocardial fatty acid (FA) and glucose oxidation, NAD+/NADH redox state and plasma levels of β‐hydroxybutyrate (β‐HOB). Male Wistar rats were instrumented with an ICV cannula in the brain lateral ventricle. After recovery and baseline assessment of cardiac function by echocardiography (ECHO), myocardial I/R was induced by temporary (60 min) ligation of the LAD. Vehicle (saline, 0.5 µL/hr) or leptin (0.62 µg/hr) was infused chronically for 28 days starting 20 min after reperfusion using osmotic minipumps connected to the ICV cannula. ECHO assessment of cardiac function was performed weekly. At the end of week 4, +dP/dtmax was accessed by LV catheterization. Hearts and plasma samples were collected for evaluation of CD36, PPAR‐δ, PDK4 and p‐PDH1/PDH1 by western blot and cardiac NAD+/NADH ratio and plasma levels of β‐OHB were measured by ELISA. Our results showed that ICV leptin treatment improved cardiac function as evidenced by increased ejection fraction 4 weeks after I/R (46±3 vs. 26±3 %) and +dP/dtmax (10387±1686 vs. 5022±442 mmHg/s) when compared with vehicle‐treated rats. ICV leptin infusion also significantly increased cardiac protein expression of CD36 (1.4±0.1 vs. 1.0±0.1 au), PPAR‐δ (1.8±0.1vs. 1.0±0.01 au), PDK4 (1.8±0.1 vs. 1.0±0.1 au) and p‐PDH1/PDH1 (2.2±0.3 vs. 1.0±0.2 au) when compared with vehicle‐treated animals. In addition, ICV leptin infusion increased cardiac NAD+/NADH ratio (6.8±2 vs. 1.02±0.3 pmol/µL) and reduced plasma levels of β‐OHB (18.2±3 vs. 62.8±7.0 nmol/µL). These results demonstrate that chronic ICV leptin infusion improves cardiac function following I/R injury and suggest that leptin’s CNS‐mediated cardioprotective effects may involve improved myocardial FA oxidation and NAD+/NADH redox state, reducing the reliance on ketone bodies (β‐OHB) as an energy source.