Thoroughly Calibrated Modular Agent-Based Model of the Human Cardiovascular and Renal Systems for Blood Pressure Regulation in Health and Disease.
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ABSTRACT:
SUBMITTER: Kutumova E
PROVIDER: S-EPMC8632703 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND:To determine if the effects of intensive lowering of systolic blood pressure (goal of less than 120?mmHg) versus standard lowering (goal of less than 140?mmHg) upon cardiovascular, renal, and safety outcomes differed by gender. METHODS:Nine thousand three hundred and sixty-one men and women aged 50 years or older with systolic blood pressure of 130?mmHg or greater, taking 0-4 antihypertensive medications, and with increased risk of cardiovascular disease, but free of diabetes, were randomly assigned to either a systolic blood pressure target of less than 120?mmHg (intensive treatment) or a target of less than 140?mmHg (standard treatment). The primary composite outcome encompassed incident myocardial infarction, heart failure, other acute coronary syndromes, stroke, or cardiovascular-related death. All-cause mortality, renal outcomes, and serious adverse events were also assessed. RESULTS:Compared with the standard treatment group, the primary composite outcome in the intensive treatment group was reduced by 16% [hazard ratio 0.84 (0.61-1.13)] in women, and by 27% in men [hazard ratio 0.73 (0.59-0.89), P value for interaction between treatment and gender is 0.45]. Similarly, the effect of the intensive treatment on individual components of the primary composite outcome, renal outcomes, and overall serious adverse events was not significantly different according to gender. CONCLUSION:In adults with hypertension but not with diabetes, treatment to a systolic blood pressure goal of less than 120?mmHg, compared with a goal of less than 140?mmHg, resulted in no heterogeneity of effect between men and women on cardiovascular or renal outcomes, or on rates of serious adverse events.ClinicalTrials.gov number, NCT01206062.
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Project description:To evaluate the time frame of resorption and tissue response of newly developed bioresorbable microspheres (BRMS) and vessel recanalization after renal embolization.Embolization of lower poles of kidneys of 20 adult rabbits was performed with BRMS (300-500 µm). Two rabbits were sacrificed immediately after embolization (day 0). Three rabbits were sacrificed after follow-up angiography at 3, 7, 10, 14, 21, and 30 days. The pathologic changes in the renal parenchyma, BRMS degradation, and vessel recanalization were evaluated histologically and angiographically.Embolization procedures were successfully performed, and all animals survived without complication. Infarcts were observed in all kidneys that received embolization harvested after day 0. Moderate degradation of BRMS (score = 1.07 ± 0.06) was observed by day 3. Of BRMS, 95% were resorbed before day 10 with scant BRMS materials remaining in the arteries at later time points. Partial vessel recanalization was observed by angiography starting on day 3, whereas new capillary formation was first identified histologically on day 7. Vascular inflammation associated with BRMS consisted of acute, heterophilic infiltrate at earlier time points (day 3 to day 10); this was resolved with the resorption of BRMS. Inflammation and fibrosis within infarcted regions were consistent with progression of infarction.BRMS were bioresorbable in vivo, and most BRMS were resorbed before day 10 with a mild tissue reaction. Vessel recanalization occurred secondary to the resorption of BRMS.
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Project description:Elevated blood pressure (BP) and renal dysfunction are complex traits representing major global health problems. Single nucleotide polymorphisms identified by genome-wide association studies have identified the Alström syndrome 1 (ALMS1) gene locus to render susceptibility for renal dysfunction, hypertension, and chronic kidney disease (CKD). Mutations in the ALMS1 gene in humans causes Alström syndrome, characterized by progressive metabolic alterations including hypertension and CKD. Despite compelling genetic evidence, the underlying biological mechanism by which mutations in the ALMS1 gene lead to the above-mentioned pathophysiology is not understood. We modeled this effect in a KO rat model and showed that ALMS1 genetic deletion leads to hypertension. We demonstrate that the link between ALMS1 and hypertension involves the activation of the renal Na+/K+/2Cl- cotransporter NKCC2, mediated by regulation of its endocytosis. Our findings establish a link between the genetic susceptibility to hypertension, CKD, and the expression of ALMS1 through its role in a salt-reabsorbing tubular segment of the kidney. These data point to ALMS1 as a potentially novel gene involved in BP and renal function regulation.
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Project description:The renin-angiotensin system regulates blood pressure and fluid balance in the body primarily via angiotensin receptor 1 (AT1R). Renal AT1R was found to be primarily responsible for Ang II-mediated hypertension. G protein-coupled receptor kinase 2 (GRK2) modulates AT1R desensitization and increased GRK2 protein expression is reported in hypertensive patients. However, the consequences of GRK2 inhibition on kidney functions remain unknown. We employed shGRK2 knockdown mice (shGRK2 mice) to test the role of GRK2 in kidney development and function that can be ultimately linked to the hypertensive phenotype detected in shGRK2 mice. GRK2 knockdown reduced kidney size, nephrogenesis and glomerular count, and impaired glomerular filtration. Glomerular damage in adult shGRK2 mice was associated with increased renin- and AT1R-mediated production of reactive oxygen species. The AT1R blocker, Losartan, normalized elevated blood pressure and markedly improved glomerular filtration in the shGRK2 knockdown mice. Our findings provide evidence for the crucial role of GRK2 in renal regulation of blood pressure. It also suggests that the detrimental outcomes of GRK2 inhibitors on the kidney should be carefully examined when used as antihypertensive.
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Project description:BackgroundGuidelines recommend intensive blood pressure (BP) lowering in patients at high risk. While placebo-controlled trials have demonstrated 22% reductions in coronary heart disease (CHD) and stroke associated with a 10-mmHg difference in systolic BP, it is unclear if more intensive BP lowering strategies are associated with greater reductions in risk of CHD and stroke. We did a systematic review to assess the effects of intensive BP lowering on vascular, eye, and renal outcomes.Methods and findingsWe systematically searched Medline, Embase, and the Cochrane Library for trials published between 1950 and July 2011. We included trials that randomly assigned individuals to different target BP levels. We identified 15 trials including a total of 37,348 participants. On average there was a 7.5/4.5-mmHg BP difference. Intensive BP lowering achieved relative risk (RR) reductions of 11% for major cardiovascular events (95% CI 1%-21%), 13% for myocardial infarction (0%-25%), 24% for stroke (8%-37%), and 11% for end stage kidney disease (3%-18%). Intensive BP lowering regimens also produced a 10% reduction in the risk of albuminuria (4%-16%), and a trend towards benefit for retinopathy (19%, 0%-34%, p = 0.051) in patients with diabetes. There was no clear effect on cardiovascular or noncardiovascular death. Intensive BP lowering was well tolerated; with serious adverse events uncommon and not significantly increased, except for hypotension (RR 4.16, 95% CI 2.25 to 7.70), which occurred infrequently (0.4% per 100 person-years).ConclusionsIntensive BP lowering regimens provided greater vascular protection than standard regimens that was proportional to the achieved difference in systolic BP, but did not have any clear impact on the risk of death or serious adverse events. Further trials are required to more clearly define the risks and benefits of BP targets below those currently recommended, given the benefits suggested by the currently available data.
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Project description:The paracellular pathway through the tight junction provides an important route for transepithelial chloride reabsorption in the kidney, which regulates extracellular salt content and blood pressure. Defects in paracellular chloride reabsorption may in theory cause deregulation of blood pressure. However, there is no evidence to prove this theory or to demonstrate the in vivo role of the paracellular pathway in renal chloride handling. Here, using a tissue-specific KO approach, we have revealed a chloride transport pathway in the kidney that requires the tight junction molecule claudin-4. The collecting duct-specific claudin-4 KO animals developed hypotension, hypochloremia, and metabolic alkalosis due to profound renal wasting of chloride. The claudin-4-mediated chloride conductance can be regulated endogenously by a protease-channel-activating protease 1 (cap1). Mechanistically, cap1 regulates claudin-4 intercellular interaction and membrane stability. A putative cap1 cleavage site has been identified in the second extracellular loop of claudin-4, mutation of which abolished its regulation by cap1. The cap1 effects on paracellular chloride permeation can be extended to other proteases such as trypsin, suggesting a general mechanism may also exist for proteases to regulate the tight junction permeabilities. Together, we have discovered a theory that paracellular chloride permeability is physiologically regulated and essential to renal salt homeostasis and blood pressure control.
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Project description:Fibroblast growth factor-23 (FGF23) is a bone-derived hormone regulating renal phosphate reabsorption and vitamin D synthesis in renal proximal tubules. Here, we show that FGF23 directly regulates the membrane abundance of the Na(+):Cl(-) co-transporter NCC in distal renal tubules by a signaling mechanism involving the FGF receptor/?Klotho complex, extracellular signal-regulated kinase 1/2 (ERK1/2), serum/glucocorticoid-regulated kinase 1 (SGK1), and with-no lysine kinase-4 (WNK4). Renal sodium (Na(+)) reabsorption and distal tubular membrane expression of NCC are reduced in mouse models of Fgf23 and ?Klotho deficiency. Conversely, gain of FGF23 function by injection of wild-type mice with recombinant FGF23 or by elevated circulating levels of endogenous Fgf23 in Hyp mice increases distal tubular Na(+) uptake and membrane abundance of NCC, leading to volume expansion, hypertension, and heart hypertrophy in a ?Klotho and dietary Na(+)-dependent fashion. The NCC inhibitor chlorothiazide abrogates FGF23-induced volume expansion and heart hypertrophy. Our findings suggest that FGF23 is a key regulator of renal Na(+) reabsorption and plasma volume, and may explain the association of FGF23 with cardiovascular risk in chronic kidney disease patients.
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Project description:We recently reported a linear association between higher systolic blood pressure (SBP) and risk of mortality in hemodialysis patients when SBP is measured outside of the dialysis unit (out-of-dialysis-unit-SBP), despite there being a U-shaped association between SBP measured at the dialysis unit (dialysis-unit-SBP) with risk of mortality. Here, we explored the relationship between SBP with cardiovascular events, which has important treatment implications but has not been well elucidated. Among 383 hemodialysis participants enrolled in the prospective CRIC study (Chronic Renal Insufficiency Cohort), multivariable splines and Cox models were used to study the association between SBP and adjudicated cardiovascular events (heart failure, myocardial infarction, ischemic stroke, and peripheral artery disease), controlling for differences in demographics, cardiovascular disease risk factors, and dialysis parameters. Dialysis-unit-SBP and out-of-dialysis-unit-SBP were modestly correlated (r=0.34; P<0.001). We noted a U-shaped association of dialysis-unit-SBP and risk of cardiovascular events, with the nadir risk between 140 and 170 mm?Hg. In contrast, there was a linear stepwise association between out-of-dialysis-unit-SBP with risk of cardiovascular events. Participants with out-of-dialysis-unit-SBP ?128 mm?Hg (top 2 quartiles) had >2-fold increased risk of cardiovascular events compared with those with out-of-dialysis-unit-SBP ?112 mm?Hg (3rd SBP quartile: adjusted hazard ratio, 2.08 [95% confidence interval, 1.12-3.87] and fourth SBP quartile: adjusted hazard ratio, 2.76 [95% confidence interval, 1.42-5.33]). In conclusion, among hemodialysis patients, although there is a U-shaped (paradoxical) association of dialysis-unit-SBP and risk of cardiovascular disease, there is a linear association of out-of-dialysis-unit-SBP with risk of cardiovascular disease. Out-of-dialysis-unit blood pressure provides key information and may be an important therapeutic target.
| S-EPMC5521215 | biostudies-literature
Project description:Fat in the renal sinus (RS), a region of the kidney in which low pressure venous and lymphatic vessels are present, may indirectly influence blood pressure. The purpose of this study was to assess the association between RS fat and control of blood pressure on receipt of antihypertensive medications. A total of 205 participants aged 55 to 85 years at risk for cardiovascular events underwent MRI assessments of abdominal and RS fat, measurement of blood pressure, and determination of the number of prescribed antihypertensive medications. Multivariable linear regression was used to determine associations among RS fat, blood pressure, and the number of prescribed antihypertensive medications. Abdominal fat averaged 416±160 cm(3) (median and interquartile range of 396 cm(3) and 308 to 518 cm(3)); intraperitoneal fat averaged 141±73 cm(3) (median and interquartile range of 129 cm(3) and 86 to 194 cm(3)); and RS fat averaged 4.6±3.2 cm(3) (median and interquartile range of 4.2 cm(3) and 2.2 to 6.6 cm(3)). After accounting for age, sex, height, body mass index, and intraperitoneal fat, RS fat correlated with the number of prescribed antihypertensive medications (P=0.010), stage II hypertension (P=0.02), and renal size (P?0.001). In conclusion, after accounting for other body fat depots and risk factors for hypertension, RS fat volume is associated with the number of prescribed antihypertensive medications and stage II hypertension. These results indicate that further studies are warranted to determine whether fat accumulation in the RS promotes hypertension.
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