Effect of Kidney Function on Relationships between Lifestyle Behaviors and Mortality or Cardiovascular Outcomes: A Pooled Cohort Analysis

Supporting Self-Management of Healthy Behaviors in Chronic Kidney Disease and Hypertension: The Supporting Self-Management of Healthy Behaviors Pilot Randomized Trial

Key Points

Background

Support programs for self-management are underutilized among people with CKD. We examined the feasibility of a smartphone-based intervention to support physical activity and BP monitoring, Supporting Self-Management of Healthy Behaviors (SMART-HABITS), for individuals with CKD and hypertension.

Methods

SMART-HABITS was piloted in a 12-week randomized cross-over trial among people with CKD and hypertension. Participants were asked to monitor BP ≥3-times/wk and step counts ≥5-times/wk. Participants were randomized to BP communication approach–self-report through text message for 6 weeks versus automatic reporting with a smartphone application (app) paired to a Bluetooth enabled BP machine for the alternate 6 weeks. The approach to monitoring and reporting steps was the same during both phases. Primary outcomes were adoption (retention and use of SMART-HABITS dashboard), adherence (% of transmitted BP and step counts), and acceptability as assessed with surveys and interviews. Secondary outcomes were reach, maintenance, CKD knowledge, digital health literacy, self-management, self-efficacy, quality of life, step counts, and BP values. Interviews were conducted at study end.

Results

Of the 47 randomized participants, 44 (94%) completed the text phase and 43 (92%) completed the app phase. The median age was 63 years, 49% were female, and 45% were Black. Retention was 91%. BP adherence was 87% in the text phase and 74% in the app phase, and step count adherence was 97%. Acceptability scores were high, and interviews largely conveyed acceptance. CKD knowledge increased but remaining survey scores did not change. Mean step counts increased from the prestudy period similarly in both phases. BP did not change over time.

Conclusions

Implementing a smartphone support tool for self-management was feasible among people with CKD and hypertension. The approach can supplement clinic-based care and potentially lead to less cardiovascular disease and CKD progression.

Clinical Trial registry name and registration number:

NCT04858295.

2024 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2024 AHA Statistical Update is the product of a full year's worth of effort in 2023 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. The AHA strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional global data, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Kidney function and cardiovascular diseases: a large-scale observational and Mendelian randomization study

Background

Prior observational studies have found an association between kidney function and cardiovascular diseases (CVDs). However, these studies did not investigate causality. Therefore, the aim of this study is to examine the causal relationship between kidney function and CVDs.

Methods

We utilized data from the eICU Collaborative Research Database (eICU-CRD) from the years 2014-2015 to evaluate the observational association between renal failure (RF) and CVDs. To investigate the causal effects of kidney function (estimated glomerular filtration rate [eGFR] and chronic kidney disease [CKD]) and CVDs (including atrial fibrillation [AF], coronary artery disease [CAD], heart failure [HF], any stroke [AS], and any ischemic stroke [AIS]), we conducted a two-sample bidirectional Mendelian randomization (MR) analysis.

Results

In the observational analysis, a total of 157,883 patients were included. After adjusting for potential confounding factors, there was no significant association between baseline RF and an increased risk of developing CVDs during hospitalization [adjusted odds ratio (OR): 1.056, 95% confidence interval (CI): 0.993 to 1.123, P = 0.083]. Conversely, baseline CVDs was significantly associated with an increased risk of developing RF during hospitalization (adjusted OR: 1.189, 95% CI: 1.139 to 1.240, P < 0.001). In the MR analysis, genetically predicted AF was associated with an increased risk of CKD (OR: 1.050, 95% CI: 1.016 to 1.085, P = 0.004). HF was correlated with lower eGFR (β: -0.056, 95% CI: -0.090 to -0.022, P = 0.001). A genetic susceptibility for AS and AIS was linked to lower eGFR (β: -0.057, 95% CI: -0.079 to -0.036, P < 0.001; β: -0.029, 95% CI: -0.050 to -0.009, P = 0.005; respectively) and a higher risk of CKD (OR: 1.332, 95% CI: 1.162 to 1.528, P < 0.001; OR: 1.197, 95% CI: 1.023 to 1.400, P = 0.025; respectively). Regarding the reverse direction analysis, there was insufficient evidence to prove the causal effects of kidney function on CVDs. Outcomes remained consistent in sensitivity analyses.

Conclusion

Our study provides evidence for causal effects of CVDs on kidney function. However, the evidence to support the causal effects of kidney function on CVDs is currently insufficient. Further mechanistic studies are required to determine the causality.

The eGFR Decline as a Risk Factor for Metabolic Syndrome in the Korean General Population: A Longitudinal Study of Individuals with Normal or Mildly Reduced Kidney Function

Metabolic syndrome (MS) is a risk factor for the development and progression of chronic kidney disease (CKD). However, it is unclear whether decreased renal function affects MS. Through a longitudinal study, we investigated the effect of estimated glomerular filtration rate (eGFR) changes on MS in participants with an eGFR above 60 mL/min/1.73 m2. A cross-sectional (n = 7107) and a 14-year longitudinal study (n = 3869) were conducted to evaluate the association between MS and eGFR changes from the Korean Genome and Epidemiology Study data. The participants were categorized by their eGFR levels (60–75, 75–90, and 90–105 versus ≥ 105 mL/min/1.73 m2). In a cross-sectional analysis, the MS prevalence was significantly increased with a decline in the eGFR in a fully adjusted model. The odds ratio of individuals with an eGFR of 60–75 mL/min/1.73 m2 was observed to be the highest (2.894; 95% confidence interval (CI), 1.984–4.223). In the longitudinal analysis, incident MS significantly increased with an eGFR decline in all the models, with the highest hazard ratio in the lowest eGFR group (1.803; 95% CI, 1.286–2.526). In joint interaction analysis, all covariates showed a significant joint effect with an eGFR decline on the incident MS. MS incidents are associated with eGFR changes in the general population without CKD.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Long-term effectiveness of a primary care practice facilitation program for chronic kidney disease management: an extended follow-up of a cluster-randomized FROM-J study

BACKGROUND

Practice facilitation program by multidisciplinary care for primary care physicians (PCPs) is expected to improve chronic kidney disease (CKD) outcomes, but there is no clear evidence of its long-term effectiveness. We have previously performed a cluster-randomized controlled trial for 3.5 years (the Frontier of Renal Outcome Modifications in Japan (FROM-J) study) with two arms-group A without the program and group B with the program. We aimed to assess the long-term effectiveness of the practice facilitation program on CKD outcomes via an extended 10-year follow-up of the FROM-J study.

METHODS

We enrolled patients who were in the FROM-J study. The primary composite endpoint comprised cardiovascular disease (CVD), renal replacement therapy initiation and a 50% decrease in the estimated glomerular filtration rate (eGFR). The secondary endpoints were survival rate, eGFR decline rate and collaboration rate between PCPs and nephrologists.

RESULTS

The occurrence of the primary composite endpoint tended to be lower in group B (group A: 27.1% versus group B: 22.1%, P = 0.051). Furthermore, CVD incidence was remarkably lower in group B (group A: 10.5% versus group B: 6.4%, P = 0.001). Although both mortality and the rate of eGFR decline were identical between both groups, the eGFR decline rate was significantly better in group B than in group A only in patients with stage G3a at enrollment (group A: 2.35 ± 3.87 mL/min/1.73 m2/year versus group B: 1.68 ± 2.98 mL/min/1.73 m2/year, P = 0.02). The collaboration rate was higher in group B.

CONCLUSIONS

The CKD practice facilitation program for PCPs reliably decreases CVD events and may reduce the progression of cases to end-stage kidney disease.

Healthy lifestyle behaviors, mediating biomarkers, and risk of microvascular complications among individuals with type 2 diabetes: A cohort study

BACKGROUND

The influence of overall lifestyle behaviors on diabetic microvascular complications remains unknown. In addition, the potential mediating biomarkers underlying the association is unclear. This study aimed to examine the associations of the combined lifestyle factors with risks of total and individual microvascular complications among patients with type 2 diabetes (T2D) and to explore the potential mediation effects of metabolic biomarkers.

METHODS AND FINDINGS

This retrospective cohort study included 15,104 patients with T2D free of macro- and microvascular complications at baseline (2006 to 2010) from the UK Biobank. Healthy lifestyle behaviors included noncurrent smoking, recommended waist circumference, regular physical activity, healthy diet, and moderate alcohol drinking. Outcomes were ascertained using electronic health records. Over a median of 8.1 years of follow-up, 1,296 cases of the composite microvascular complications occurred, including 558 diabetic retinopathy, 625 diabetic kidney disease, and 315 diabetic neuropathy, with some patients having 2 or 3 microvascular complications simultaneously. After multivariable adjustment for sociodemographic characteristics, history of hypertension, glycemic control, and medication histories, the hazard ratios (95% confidence intervals (CIs)) for the participants adhering 4 to 5 low-risk lifestyle behaviors versus 0 to 1 were 0.65 (0.46, 0.91) for diabetic retinopathy, 0.43 (0.30, 0.61) for diabetic kidney disease, 0.46 (0.29, 0.74) for diabetic neuropathy, and 0.54 (0.43, 0.68) for the composite outcome (all Ps-trend ≤0.01). Further, the population-attributable fraction (95% CIs) of diabetic microvascular complications for poor adherence to the overall healthy lifestyle (<4 low-risk factors) ranged from 25.3% (10.0%, 39.4%) to 39.0% (17.7%, 56.8%). In addition, albumin, HDL-C, triglycerides, apolipoprotein A, C-reactive protein, and HbA1c collectively explained 23.20% (12.70%, 38.50%) of the associations between overall lifestyle behaviors and total diabetic microvascular complications. The key limitation of the current analysis was the potential underreporting of microvascular complications because the cases were identified via electronic health records.

CONCLUSIONS

Adherence to overall healthy lifestyle behaviors was associated with a significantly lower risk of microvascular complications in patients with T2D, and the favorable associations were partially mediated through improving biomarkers of glycemic control, systemic inflammation, liver function, and lipid profile.

Guideline-Directed Medical Therapy Attainment and Outcomes in Dialysis-Requiring Versus Nondialysis Chronic Kidney Disease in the ISCHEMIA-CKD Trial

BACKGROUND

Patients with chronic kidney disease (CKD) on dialysis (CKD G5D) have worse cardiovascular outcomes than patients with advanced nondialysis CKD (CKD G4-5: estimated glomerular filtration rate <30 mL/[min·1.73m2]). Our objective was to evaluate the relationship between achievement of cardiovascular guideline-directed medical therapy (GDMT) goals and clinical outcomes for CKD G5D versus CKD G4-5.

METHODS

This was a subgroup analysis of ISCHEMIA-CKD (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches-Chronic Kidney Disease) participants with CKD G4-5 or CKD G5D and moderate-to-severe myocardial ischemia on stress testing. Exposures included dialysis requirement at randomization and GDMT goal achievement during follow-up. The composite outcome was all-cause mortality or nonfatal myocardial infarction. Individual GDMT goal (smoking cessation, systolic blood pressure <140 mm Hg, low-density lipoprotein cholesterol <70 mg/dL, statin use, aspirin use) trajectory was modeled. Percentage point difference was estimated for each GDMT goal at 24 months between CKD G5D and CKD G4-5, and for association with key predictors. Probability of survival free from all-cause mortality or nonfatal myocardial infarction by GDMT goal achieved was assessed for CKD G5D versus CKD G4-5.

RESULTS

A total of 415 CKD G5D and 362 CKD G4-5 participants were randomized. Participants with CKD G5D were less likely to receive statin (-6.9% [95% CI, -10.3% to -3.7%]) and aspirin therapy (-3.0% [95% CI, -5.6% to -0.6%]), with no difference in other GDMT goal attainment. Cumulative exposure to GDMT achieved during follow-up was associated with reduction in all-cause mortality or nonfatal myocardial infarction (hazard ratio, 0.88 [95% CI, 0.87-0.90]; per each GDMT goal attained over 60 days), irrespective of dialysis status.

CONCLUSIONS

CKD G5D participants received statin or aspirin therapy less often. Cumulative exposure to GDMT goals achieved was associated with lower incidence of all-cause mortality or nonfatal myocardial infarction in participants with advanced CKD and chronic coronary disease, regardless of dialysis status.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01985360.

Modifiable Lifestyle Behaviors and CKD Progression: A Narrative Review

Living a healthy lifestyle is one of the safest and most cost-effective ways to improve one's quality of life and prevent and/or manage chronic disease. As such, current CKD management guidelines recommend that patients adhere to a healthy diet, perform ≥150 minutes per week of physical activity, manage their body weight, abstain from tobacco use, and limit alcohol. However, there are limited studies that investigate the relationship between these lifestyle factors and the progression of CKD among people with established CKD. In this narrative review, we examine the reported frequencies of health lifestyle behavior engagement among individuals with non-dialysis-dependent CKD and the existing literature that examines the influences of diet, physical activity, weight management, alcohol consumption, and tobacco use on the progression of CKD, as measured by decline in GFR, incident ESKD, or elevated proteinuria or albuminuria in individuals with CKD. Many of the available studies are limited by length of follow-up and small sample sizes, and meta-analyses were limited because the studies were sparse and had heterogeneous classifications of behaviors and/or referent groups and of CKD progression. Further research should be done to determine optimal methods to assess behaviors to better understand the levels at which healthy lifestyle behaviors are needed to slow CKD progression, to investigate the effect of combining multiple lifestyle behaviors on important clinical outcomes in CKD, and to develop effective techniques for behavior change. Despite the lack of evidence of efficacy from large trials on the ability of lifestyle behaviors to slow CKD progression, maintaining a healthy lifestyle remains a cornerstone of CKD management given the undisputed benefits of healthy lifestyle behaviors on cardiovascular health, BP control, and survival.

Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2022 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population and an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, and the global burden of cardiovascular disease and healthy life expectancy.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Chronic kidney disease, physical activity, and cognitive function in older adults- results from the National Health and Nutrition Examination Survey (2011-2014)

BACKGROUND

Cognitive impairment is common among persons with chronic kidney disease (CKD) due in part to reduced kidney function. Given that physical activity (PA) is known to mitigate cognitive decline, we examined whether associations between CKD stage and global/domain-specific cognitive function differs by PA.

METHODS

We leveraged 3,223 participants (aged≥60years) enrolled in National Health and Nutrition Examination Survey (NHANES,2011-2014), with at least one measure of objective cognitive function (immediate recall [CERAD-WL], delayed recall [CERAD-DR], verbal fluency [AF], executive function/processing speed [DSST], global [average of 4 tests]) or self-perceived memory decline [SCD]. We quantified the association between CKD stage (no CKD: eGFR≥60 mL/min/1.73m2 and albuminuria(ACR)<30 mg/g; stage G1-G3: eGFR≥60mL/min/1.73m2 and ACR≥30mg/g or eGFR 30-59mL/min/1.73m2; stage G4-G5: eGFR<30mL/min/1.73m2) and cognitive function using linear regression (objective measures) and logistic regression (SCD), accounting for sampling weights for nationally-representative estimates. We tested whether associations differed by physical activity (Global Physical Activity Questionnaire, high PA≥600MET*min/week vs. low PA<600MET*min/week) using a Wald test.

RESULTS

Among NHANES participants, 34.9% had CKD stageG1-G3, 2.6% had stageG4-G5, and 50.7% had low PA. CKD stageG4-G5 was associated with lower global cognitive function (difference = -0.38SD, 95%CI:-0.62,-0.15). This association differed by PA (pinteraction = 0.01). Specifically, among participants with low PA, those with CKD stageG4-G5 had lower global cognitive function (difference = -0.57SD, 95%CI: -0.82,-0.31) compared to those without CKD. Among those with high PA, no difference was found (difference = 0.10SD, 95%CI:-0.29,0.49). Similarly, CKD stage was only associated with immediate recall, verbal fluency, executive function, and processing speed among those with low PA; no associations were observed for delayed recall or self-perceived memory decline.

CONCLUSIONS

CKD is associated with lower objective cognitive function among those with low, but not high PA. Clinicians should consider screening older patients with CKD who have low PA for cognitive impairment and encourage them to meet PA guidelines.

Lifestyle interventions for preventing and ameliorating CKD in primary and secondary care

PURPOSE OF REVIEW

Despite the growth in chronic kidney disease (CKD) epidemics, evidence-based lifestyle recommendations for primary prevention of CKD are limited by reliance on observational studies and predominantly pilot clinical trials.

RECENT FINDINGS

Emerging data have shown lifestyle modification strategies for primary CKD prevention with the most evidence favoring a healthy dietary pattern (rich in fruit, vegetables, potassium and have a higher plant-based to animal protein ratio), and diet low in sodium, being physically active, avoiding tobacco smoking, moderating alcohol consumption and maintaining a healthy body weight. The way these behavioral interventions can be implemented in practice should consider their synergistic benefit as well as mechanisms to facilitate long-term behavior change. Sustaining long-term behavior change remains a challenge in practice, particularly due to a lack of healthcare resources and behavior relapse. Some suggestions to mitigate this include ensuring adequate time is spent in intervention codesign and planning, utilizing adaptive trial/intervention designs with regular intervention tailoring for intervention dose, intensity, duration, and modality.

SUMMARY

A number of modifiable lifestyle behaviors consistently associate with developing CKD in the community. The current evidence base, despite its inherent limitations, may inform both public health recommendations and clinical practice.

Healthy Lifestyle and Mortality Among Adults Receiving Hemodialysis: The DIET-HD Study

RATIONALE & OBJECTIVE

A healthy lifestyle promotes cardiovascular health and reduces cardiac-related mortality in the general population but its benefits for people receiving maintenance hemodialysis are uncertain.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

5,483 of 9,757 consecutive adults receiving maintenance hemodialysis (January 2014 to June 2017, median dialysis vintage: 3.6 yrs) in a multinational private dialysis network and with complete lifestyle data.

EXPOSURES

Based on the American Heart Association's recommendations for cardiovascular prevention, a modified healthy lifestyle score was the sum of four components addressing use of smoking tobacco, physical activity, diet, and control of systolic blood pressure.

OUTCOMES

Cardiovascular and all-cause mortality.

ANALYTICAL APPROACH

Adjusted proportional hazards (aHRs) regression analyses with country as a random effect to estimate the associations between lifestyle score (low [0-2 points] as the referent, medium [3-5], and high [6-8]) and mortality. Associations were expressed as aHRs with 95% confidence intervals (CIs).

RESULTS

During a median of 3.8 years (17,451 person-years in total), there were 2,163 deaths, of which 826 were related to cardiovascular disease. Compared to patients with a low lifestyle score, the aHRs (95% CIs) for all-cause mortality among those with medium and high lifestyle scores were 0.75 (0.65-0.85) and 0.64 (0.54-0.76), respectively. Compared to patients with a low lifestyle score, the aHRs (95% CIs) for cardiovascular mortality among those with medium and high lifestyle scores were 0.73 (0.59-0.91) and 0.65 (0.49-0.85), respectively.

LIMITATIONS

Self-reported lifestyle, data-driven approach.

CONCLUSIONS

A healthier lifestyle is associated with lower all-cause and cardiovascular mortality among patients receiving maintenance hemodialysis.

Superimposition of metabolic syndrome magnifies post-stenotic kidney injury in dyslipidemic pigs

BACKGROUND

Dyslipidemia aggravates kidney injury distal to atherosclerotic renal artery stenosis (ARAS). Besides dyslipidemia, metabolic syndrome (MetS) also involves development of obesity and insulin-resistance (IR). We hypothesized that concurrent obesity and IR magnify swine stenotic-kidney damage beyond dyslipidemia.

METHODS

Pigs with unilateral RAS were studied after 16 weeks of atherogenic diets without (ARAS) or with (MetS + RAS) development of obesity/IR (n=6 each). Additional pigs on normal diet served as normal or non-dyslipidemic RAS controls (n=6 each). Stenotic-kidney renal blood flow (RBF), glomerular filtration rate (GFR), and microvascular architecture were studied using CT, and oxygenation was studied using blood oxygen level-dependent magnetic-resonance-imaging. We further compared kidney adiposity, oxidative stress, inflammation, apoptosis, fibrosis, and systemic levels of oxidative and inflammatory cytokines.

RESULTS

ARAS and MetS + RAS developed hypertension and dyslipidemia, and MetS + RAS also developed obesity and IR. RBF and GFR were similarly decreased in all post-stenotic pig kidneys compared to normal pig kidneys, yet MetS + RAS aggravated and expanded medullary hypoxia and microvascular loss. RAS and ARAS increased systemic levels of tumor necrosis factor (TNF)-α, which were further elevated in MetS + RAS. Renal oxidative stress and TNF-α expression increased in ARAS and further in MetS + RAS, which also upregulated expression of anti-angiogenic angiostatin, and magnified apoptosis, tubular injury, and fibrosis.

CONCLUSION

Beyond dyslipidemia, obesity and insulin-resistance aggravate damage in the post-stenotic kidney in MetS, despite relative hyperfiltration-related preservation of renal function. These observations underscore the need to control systemic metabolic disturbances in order to curb renal damage in subjects with ischemic kidney disease.