Obesity and kidney disease: Hidden consequences of the epidemic

Characterization of feline nonsteroidal anti-inflammatory drug activated gene-1 (fNAG-1) and its protective function in kidney cells

BACKGROUND

Domestic cats are susceptible to obesity and chronic renal failure, leading to significant health risks. Nonsteroidal anti-inflammatory drug-activated gene (NAG-1), also known as growth differentiation factor 15 (GDF15), is a member of the transforming growth factor-β superfamily and has been associated with anti-obesity properties and preservation of kidney function. While the NAG-1 sequence has been extensively studied in several species, a comprehensive understanding of feline NAG-1 remains limited. This study aimed to investigate the nucleotide sequence of feline NAG-1 and its biological role in kidney protection through in-vitro experiments.

METHODS

The feline NAG-1 cDNA was isolated from the feline uterus, and its sequence was analyzed and compared to sequences from other species, including humans. Expression patterns of feline NAG-1 in various tissues, particularly the liver and kidney, were determined. Furthermore, the effects of different phytochemicals and NSAIDs known to induce NAG-1 expression were assessed using Crandell-Rees Feline Kidney (CRFK) cells.

RESULTS

The analysis revealed that feline NAG-1 shares similarities with human NAG-1 and exhibits high expression levels in the liver and kidney of cats. Treatment with tolfenamic acid, quercetin, and resveratrol significantly increased NAG-1 expression in CRFK cells. Subsequently, CRFK cells overexpressing feline NAG-1 were utilized to investigate the functional roles of NAG-1 in feline kidney health. High-content screening analysis demonstrated that NAG-1 overexpression in cat kidney cells enhanced mitochondrial membrane potential, reduced reactive oxygen species (ROS) generation in both whole cells and mitochondria, and downregulated the expression of Bax, a pro-apoptotic protein, under conditions of ROS-induced stress. These findings indicate the renoprotective role of NAG-1.

CONCLUSION

This study highlights the significant role of NAG-1 in feline kidney cells, revealing its high expression in the liver and kidney and demonstrating its protective effects on kidney function. These results underscore the potential of NAG-1 as a key factor in kidney protection. Future research should focus on further elucidating the molecular pathways involved and exploring therapeutic strategies to harness NAG-1 for managing obesity-related renal dysfunction in cats.

The Composite Number Needed to Treat for Semaglutide in Populations with Overweight or Obesity and Established Cardiovascular Disease Without Diabetes

INTRODUCTION

Number needed to treat (NNT), an outcome measure derived from the estimated risk results of clinical trials, is widely used to demonstrate value to stakeholders by identifying how many patients require treatment to avoid one event of interest. However, NNTs calculated for primary trial endpoints may underestimate a treatment's value by not considering other outcomes. In this secondary analysis of data from the SELECT cardiovascular (CV) outcomes trial, we aimed to determine the NNT for semaglutide for major adverse cardiovascular events (MACE), in addition to NNTs when other clinically and payer-relevant outcomes are included.

METHODS

This study is a secondary analysis of data from the randomized, double-blind SELECT trial (ClinicalTrials.gov NCT03574597) of once-weekly subcutaneous administration of semaglutide compared with placebo in 17,604 patients with overweight or obesity and with established cardiovascular disease (CVD) (39.8 months mean follow-up). The outcomes were NNT3P-MACE (based upon the trial's composite primary endpoint of death from cardiovascular causes, non-fatal myocardial infarction, non-fatal stroke), NNTEXTENDED (inclusive of NNT3P-MACE, hospitalization for any cause, coronary revascularization, and non-CV death), and NNTCKM (inclusive of NNTEXTENDED, glycated hemoglobin level [HbA1c] ≥ 6.5%, and a 5-point nephropathy composite).

RESULTS

The relative risk reductions observed for the events comprising the NNTs were 20% (NNT3P-MACE), 20% (NNTEXTENDED), and 41% (NNTCKM). At 1 and 4 years post initiation of semaglutide, NNT3P-MACE was 125 and 58, NNTEXTENDED was 49 and 25, and NNTCKM was 20 and 11, respectively.

CONCLUSION

When clinically and payer-relevant outcomes from the SELECT trial are included in calculations of NNT, semaglutide was associated with greater risk reductions and lower estimates of NNT than for the primary endpoint alone. Our findings suggest that including the broader effects of semaglutide beyond the primary trial endpoint recognizes additional value to stakeholders.

Chronic Kidney Disease Risk Awareness, Dietary Intake, and Food Security Among Black Male College Students

OBJECTIVES

Nutrition, lifestyle factors, and awareness of chronic kidney disease (CKD) risk are vital tools for preventing or delaying its development and progression in Black American (BA) males. Few published studies assess awareness of CKD risk in BA male college students despite being at high risk. This study aimed to 1) assess the awareness of CKD risk among BA male college students and 2) identify dietary and lifestyle habits related to CKD risk.

METHODS

This was a cross-sectional online survey utilizing a network sampling technique. Inclusion criteria were self-identification as a BA male and current enrollment in a university. Participants were recruited through publicly available social media sites and emails. The online questionnaire contained demographic, health status, and food security items. Pearson's correlations explored associations between continuous variables; independent samples t-tests compared mean scores of responses between perceived risk of disease groups.

RESULTS

Sixty-seven participants completed the survey. Only 22.4% perceived they were at increased risk for kidney disease, while 49.3% felt at increased risk for developing hypertension (HTN). More respondents (32.8%) also felt at increased risk for developing diabetes than kidney disease. Dietary sodium restriction was reported by 34.3%, while only 14.9% had been advised to do so by a health-care provider. Half of the respondents were deemed food insecure, and 17.86% were categorized as experiencing very low food security.

CONCLUSION

Awareness of CKD risk is low for BA male college students and lags behind awareness of HTN and diabetes risk. There may be a lack of knowledge regarding CKD as a long-term complication of HTN and diabetes. Dietary sodium restriction is marginal, and food security is a significant challenge in this high-risk group. Educational initiatives are needed to increase awareness of CKD risk among BA male college students.

Patients with type 1 diabetes are at elevated risk of developing new hypertension, chronic kidney disease and diabetic ketoacidosis after COVID-19: Up to 40 months' follow-up

AIM

The aim was to investigate whether COVID-19 increases new incidence of hypertension (HTN), chronic kidney disease (CKD) and diabetic ketoacidosis (DKA) in patients with type 1 diabetes (T1D) up to 40 months post-infection.

MATERIALS AND METHODS

Three groups of patients from the Montefiore Health System in the Bronx (1 March 2020 to 1 July 2023) were studied: T1D patients hospitalized for COVID-19 (H-COVID-19, n = 511), T1D patients with COVID-19 but not hospitalized for COVID-19 (NH-COVID-19, n = 306) and T1D patients without a positive COVID-19 test on record (non-COVID-19, n = 1547). COVID-19 patients were those with a positive polymerase-chain-reaction test on record, and non-COVID-19 patients were either tested negative or not tested on record. Cumulative incidences and adjusted hazard ratios (aHR) with 95% confidence intervals (CI) were computed with adjustment for competing risks.

RESULTS

Compared to non-COVID-19 patients, both H-COVID-19 (unadjusted 19.72% vs. 3.14%, p < 0.001; aHR = 7.55 [3.33, 17.06], p < 0.001) and NH-COVID-19 (10.26% vs. 3.14%, p = 0.004; aHR = 5.08 [2.19, 11.78], p < 0.001) patients were more likely to develop new HTN. Compared to non-COVID-19 patients, both H-COVID-19 (11.41% vs. 1.14%, p < 0.001; aHR = 9.76 [4.248, 22.25], p < 0.001) and NH-COVID-19 (7.69% vs. 1.14%, p < 0.001; aHR = 6.54 [2.91, 14.67], p < 0.001) patients were more likely to develop new CKD. Compared to non-COVID-19 patients, both H-COVID-19 (4.09% vs. 1.06%, p < 0.001; aHR = 12.24 [4.09, 36.59], p < 0.001) and NH-COVID-19 (3.06% vs. 1.06%, p = 0.035; aHR = 12.94 [4.09, 40.89], p < 0.001) patients were more likely to develop new DKA at follow-up.

CONCLUSION

T1D patients with COVID-19 are at higher risk of developing new HTN, CKD and DKA compared to T1D patients without COVID-19.

Renal sinus adipose tissue: exploratory study of metabolic features and transcriptome compared with omental and subcutaneous adipose tissue

OBJECTIVE

The objective was to study metabolic characteristics and transcriptome of renal sinus adipose tissue (RSAT) located around renal arteries and veins.

METHODS

Adipose tissue biopsies from RSAT, omental (OAT), and subcutaneous (SAT) depots were obtained from healthy kidney donors (20 female, 20 male). Adipocyte glucose uptake rate and cell size were measured, and gene expression analyses using transcriptomics were performed.

RESULTS

RSAT adipocytes were significantly smaller, with a higher basal glucose uptake rate, than adipocytes from SAT and OAT. Transcriptomic analyses revealed 29 differentially expressed genes between RSAT and OAT (RSAT: 23 lower, 6 higher) and 1214 differentially expressed genes between RSAT and SAT (RSAT: 859 lower, 355 higher). RSAT demonstrated molecular resemblance to OAT, both exhibiting lower metabolic gene expression and higher expression of immune-related pathways, including IL-17, TNFα, and NF-κB signaling than SAT. Weighted gene coexpression network analysis associated RSAT with immune response and nucleic acid transport processes. Despite its location near the renal hilum, RSAT closely resembled OAT and there was a lack of expression in the classical brown adipose tissue genes. Gene enrichment analyses suggest an inflammatory environment in RSAT compared with SAT and, to some extent, OAT.

CONCLUSIONS

The findings suggest specific RSAT functions that could impact renal function and, possibly, the development of renal and cardiometabolic disorders.

Exploring the interplay between kidney function and urinary metabolites in young adults: the African-PREDICT study

The exposure to modifiable risk factors at young ages have been linked to premature fatal and non-fatal cardiovascular and kidney outcomes. The use of urinary metabolomics has shown strong predictability of kidney function and cardiovascular disease (CVD). We therefore determined the associations between estimated glomerular filtration rate (eGFR) and urinary metabolites in young adults with and without CVD risk factors. Apparently healthy Black and White sexes were included (aged 20-30 years) and categorised by the presence or absence of risk factors, i.e., obesity, physical inactivity, smoking, excessive alcohol intake, masked hypertension, hyperglycemia, dyslipidemia and low socio-economic status, forming the CVD risk group (N = 1036), CVD risk clusters (i.e. presenting with 1 CVD risk factor (N = 344), 2 CVD risk factors (N = 360) and 3 + CVD risk factors (N = 332)) and the control group (N = 166). eGFR was calculated with CKD-EPI equations. A targeted metabolomics approach using liquid chromatography-tandem mass spectrometry was used to measure amino acids and acylcarnitines. Lower cystatin C-based eGFR were indicated in the CVD risk group, 2 and 3 + CVD risk clusters compared to the control group (all P ≤ 0.033). In the CVD risk group, eGFR associated positively with histidine, lysine, asparagine, glycine, serine, glutamine, dimethylglycine, threonine, alanine, creatine, cystine, methionine, tyrosine, pyroglutamic acid, leucine/isoleucine, aspartic acid, tryptophan, glutamic acid, free carnitine, acetylcarnitine, propionylcarnitine, isovalerylcarnitine, octanoylcarnitine and decanoylcarnitine (all P ≤ 0.044), with similar results found in the CVD risk clusters, particularly the 2 CVD risk cluster. eGFR was positively associated with metabolites linked to aromatic amino acid and branched-chain amino acid metabolism, energy metabolism and oxidative stress. These findings may indicate altered reabsorption of these metabolites or altered metabolic regulation to preserve renal health in the setting of CVD risk factors at this young age without established CVD.

Long-Term Protective Effects and Mechanisms of Gastric Bypass Surgery on the Kidneys in Hypertensive Obese Rat

OBJECTIVE

Investigate the long-term protective effects of gastric bypass surgery on the kidneys of hypertensive obese rats to better understand the role of gastric bypass surgery in preventing renal injury in humans with hypertension and obesity.

METHODS

Compare 6-week-old spontaneously hypertensive rats, including 30 Roux-en-Y gastric bypass (RYGB) and 30 sham operations. Body weight and blood pressure were monitored before and up to 12 months after the operation. Blood lipids, blood creatinine, and blood urea nitrogen were measured. Kidney pathology was assessed using HE staining, while renal fibrosis was observed via Masson staining. Inflammatory indicators were examined by ELISA. The expression of the NLRP3 gene in the kidney was measured using immunofluorescence and western blot, and the changes in key pathways including ASC/IL-1β protein were verified.

RESULTS

RYGB reduced the body weight of hypertensive obese rats and had a protective effect on blood pressure. Additionally, the bypass effectively mitigated renal inflammation and fibrosis. Moreover, RYGB modulated the expression of NLRP3 and prevented kidney damage via the ASC/IL-1 pathway.

CONCLUSION

This study validates that RYGB effectively attains sustained blood pressure control in hypertensive obese rats and has a potential kidney-protective mechanism via the NLRP3-ASC/IL-1β pathway.

Renal Endocannabinoid Dysregulation in Obesity-Induced Chronic Kidney Disease in Humans

The endocannabinoid system (ECS) regulates various physiological processes, including energy homeostasis and kidney function. ECS upregulation in obese animals and humans suggests a potential link to obesity-induced chronic kidney disease (CKD). However, obesity-induced ECS changes in the kidney are mainly studied in rodents, leaving the impact on obese humans unknown. In this study, a total of 21 lean and obese males (38-71 years) underwent a kidney biopsy. Biochemical analysis, histology, and endocannabinoid (eCB) assessment were performed on kidney tissue and blood samples. Correlations between different parameters were evaluated using a comprehensive matrix. The obese group exhibited kidney damage, reflected in morphological changes, and elevated kidney injury and fibrotic markers. While serum eCB levels were similar between the lean and obese groups, kidney eCB analysis revealed higher anandamide in obese patients. Obese individuals also exhibited reduced expression of cannabinoid-1 receptor (CB1R) in the kidney, along with increased activity of eCB synthesizing and degrading enzymes. Correlation analysis highlighted connections between renal eCBs, kidney injury markers, obesity, and related pathologies. In summary, this study investigates obesity's impact on renal eCB "tone" in humans, providing insights into the ECS's role in obesity-induced CKD. Our findings enhance the understanding of the intricate interplay among obesity, the ECS, and kidney function.

Bariatric Surgery in Severely Obese Kidney Donors Before Kidney Transplantation: A Retrospective Study

BACKGROUND

Bariatric surgery (BS) is the optimal approach for sustained weight loss and may alter donation candidacy in potential donors with obesity. We evaluated the long-term effects of nephrectomy after BS on metabolic profile, including body mass index, serum lipids and diabetes, and kidney function of donors.

METHODS

This was a single-center retrospective study. Live kidney donors who underwent BS before nephrectomy were matched for age, gender, and body mass index with patients who underwent BS alone and with donors who underwent nephrectomy alone. Estimated glomerular filtration rate (eGFR) was calculated according to Chronic Kidney Disease Epidemiology Collaboration and adjusted to individual body surface area to create absolute eGFR.

RESULTS

Twenty-three patients who underwent BS before kidney donation were matched to 46 controls who underwent BS alone. At the last follow-up, the study group showed significantly worse lipid profile with low-density lipoprotein of 115 ± 25 mg/dL versus the control group with low-density lipoprotein of 99 ± 29 mg/dL ( P  = 0.036) and mean total cholesterol of 191 ± 32 versus 174 ± 33 mg/dL ( P  = 0.046). The second control group of matched nonobese kidney donors (n = 72) had similar serum creatinine, eGFR, and absolute eGFR as the study group before nephrectomy and 1 y after the procedure. At the end of follow-up, the study group had significantly higher absolute eGFR compared with the control group (86 ± 21 versus 76 ± 18 mL/min; P  = 0.02) and similar serum creatinine and eGFR.

CONCLUSIONS

BS before live kidney donation is a safe procedure that could increase the donor pool and improve their health in the long run. Donors should be encouraged to maintain their weight and avoid adverse lipid profile and hyperfiltration.

Neutralizing MIP3α Reduces Renal Immune Cell Infiltration and Progressive Renal Injury in Young Obese Dahl Salt-Sensitive Rats

Recently, we reported that the early progression of renal injury in obese Dahl salt-sensitive leptin receptor mutant (SSLepRmutant) rats was associated with increased macrophage inflammatory protein 3-α (MIP3α) expression prior to puberty. Therefore, this study tested the hypothesis that MIP3α plays a role in recruiting immune cells, thereby triggering renal inflammation and early progressive renal injury in SSLepRmutant rats prior to puberty. Four-week-old Dahl salt-sensitive (SS) and SSLepRmutant rats either served as control (IgG; intraperitoneal, every other day) or received MIP3α-neutralizing antibody (MNA; 100 µg/kg) for 4 weeks. MNA reduced circulating and renal MIP3α levels and proinflammatory immune cells by 50%. Although MNA treatment did not affect blood glucose and plasma cholesterol levels, MNA markedly decreased insulin resistance and triglyceride levels in SSLepRmutant rats. We observed no differences in mean arterial pressure (MAP) between SS and SSLepRmutant rats, and MNA had no effect on MAP in either strain. Proteinuria was significantly increased in SSLepRmutant rats versus SS rats over the course of the study. Treatment with MNA markedly decreased proteinuria in SSLepRmutant rats while not affecting SS rats. Also, MNA decreased glomerular and tubular injury and renal fibrosis in SSLepRmutant rats while not affecting SS rats. Overall, these data indicate that MIP3α plays an important role in renal inflammation during the early progression of renal injury in obese SSLepRmutant rats prior to puberty. These data also suggest that MIP3α may be a novel therapeutic target to inhibit insulin resistance and prevent progressive proteinuria in obese children. SIGNIFICANCE STATEMENT: Childhood obesity is increasing at an alarming rate and is now being associated with renal disease. Although most studies have focused on the mechanisms of renal injury associated with adult obesity, few studies have examined the mechanisms of renal injury involved during childhood obesity. In the current study, we observed that the progression of renal injury in obese Dahl salt-sensitive leptin receptor mutant rats was associated with an increase in MIP3α, a chemokine, before puberty, and inhibition of MIP3α markedly reduced renal injury.

Chemotherapy and Anticancer Drugs Adjustment in Obesity: A Narrative Review

BACKGROUND

Obese individuals have higher rates of cancer incidence and cancer- related mortality. The worse chemotherapy outcomes observed in this subset of patients are multifactorial, including the altered physiology in obesity and its impact on pharmacokinetics, the possible increased risk of underdosing, and treatment-related toxicity.

AIMS

The present review aimed to discuss recent data on physiology, providing just an overall perspective and pharmacokinetic alterations in obesity concerning chemotherapy. We also reviewed the controversies of dosing adjustment strategies in adult and pediatric patients, mainly addressing the use of actual total body weight and ideal body weight.

METHODS

This narrative review tried to provide the best evidence to support antineoplastic drug dosing strategies in children, adolescents, and adults.

RESULTS

Cardiovascular, hepatic, and renal alterations of obesity can affect the distribution, metabolism, and clearance of drugs. Anticancer drugs have a narrow therapeutic range, and variations in dosing may result in either toxicity or underdosing. Obese patients are underrepresented in clinical trials that focus on determining recommendations for chemotherapy dosing and administration in clinical practice. After considering associated comorbidities, the guidelines recommend that chemotherapy should be dosed according to body surface area (BSA) calculated with actual total body weight, not an estimate or ideal weight, especially when the intention of therapy is the cure.

CONCLUSION

The actual total body weight dosing appears to be a better approach to dosing anticancer drugs in both adults and children when aiming for curative results, showing no difference in toxicity and no limitation in treatment outcomes compared to adjusted doses.

Renoprotective effect of empagliflozin in cafeteria diet-induced insulin resistance in rats: Modulation of HMGB-1/TLR-4/NF-κB axis

AIM

Cafeteria diet (CAF) is a well-established model used to mimic what occurs in human upon eating junk and ultra-processed food. This study aimed to investigate the possible protective impact of empagliflozin (EMPA) against CAF-induced insulin resistance (IR) in rats and the possible underlying mechanisms.

MAIN METHODS

Rats were fed on CAF diet for 12 weeks while treatment with EMPA (10 & 30 mg/kg/day, orally) and/or metformin (MET) (100 mg/kg/day, orally) started at day 29.

KEY FINDINGS

Oral administration of EMPA and/or MET significantly and dose-dependently succeeded to attenuate CAF-induced obesity which was evidenced by decreased oral glucose tolerance test (AUC_OGTT), insulin tolerance test (AUC_ITT) and decreased fasting serum insulin level besides improving the histopathological alterations induced by CAF. Moreover, EMPA significantly mitigated CAF-induced elevation in serum levels of creatinine urea, transaminases (ALT and AST), and increased albumin level as well as improving dyslipidemia and oxidative stress. Furthermore, EMPA markedly reduced renal levels of high mobility group box 1 (HMGB-1), toll like receptor4 (TLR-4) and nuclear factor κB (NF-κB) as well as decreasing the expression of tumor necrosis factor α (TNF-α) and Caspase 3. Combining EMPA₃₀ with MET synergistically improved dyslipidemia, oxidative stress and enhanced kidney function.

SIGNIFICANCE

EMPA administration could confer protection against CAF-induced IR and its complications through its hypoglycemic, insulin-sensitizing, hypolipidemic, hepatoprotective, renoprotective, anti-inflammatory, anti-oxidant and anti-apoptotic properties. Also, our findings highlighted the synergistic effect of combining EMPA₃₀ with MET so this combination might be promising in treatment of IR.

Obesity and the increased risk for COVID-19: mechanisms and nutritional management

The global COVID-19 (coronavirus disease 2019) pandemic has become a complex problem that overlaps with a growing public health problem, obesity. Obesity alters different components of the innate and adaptive immune responses, creating a chronic and low-grade state of inflammation. Nutritional status is closely related to a better or worse prognosis of viral infections. Excess weight has been recognised as a risk factor for COVID-19 complications. In addition to the direct risk, obesity triggers other diseases such as diabetes and hypertension, increasing the risk of severe COVID-19. The present review explains the diets that induce obesity and the importance of different foods in this process. We also review tissue disruption in obesity, leading to impaired immune responses and the possible mechanisms by which obesity and its co-morbidities increase COVID-19 morbidity and mortality. Nutritional strategies that support the immune system in patients with obesity and with COVID-19 are also discussed in light of the available data, considering the severity of the infection. The discussions held may contribute to combating this global emergency and planning specific public health policy.

Cystatin and Glomerular Filtration Rate in Obese Versus Non-obese Adolescents

Background: Obesity is well known as an independent risk factor for chronic kidney disease. Thus meticulous assessment of renal function is more essential in obese individuals. Glomerular filtration rate (GFR) is commonly estimated based on serum creatinine (Cr).  However, using Cr as marker of kidney function has some limitations and Cystatin C has been reported as an alternative marker. Aim of work: This study was designed to assess renal function using both GFR and cystatin in obese adolescents. Methods: This case-control study enrolled ninety Egyptian adolescents aged between 10 and 18 years old who were divided equally into two groups according to body mass index (obese and non-obese).  Each participant was subjected to full medical history taking, anthropometric measures, and Laboratory investigation including CBC, serum Cr, estimated GFR and cystatin C. Results:  Serum Cr level was significantly higher in obese adolescents compared to non-obese mean value (0.94) and (0.79) resepectively. Also, eGFR based on Cr was significantly lower in obese group compared to controls (73.1) and ( (85.30)respectively. Cystatin C showed non-significant higher levels in obese group versus controls with mean value (2.28) and (1.85)respectively. Cystatin C at Cut-off value of 1.525 and 95% CI showed sensitivity of 47.2% and specificity of 63.9% for evaluation of kidney affection in obese children and adolescences. Conclusion: GFR is affected in obese adolescence with elevation of serum creatinine and unexpected non significant elevation of cystatin C in obese adolescence when compared by control group. Keywords: Cystatin, Creatinine, Pediatric obesity, GFR, renal function.

Development and Relative Validity of the Chronic Kidney Disease Short Food Frequency Questionnaire (CKD SFFQ) to Determine Diet Quality and Dietary Habits among Adults with Chronic Kidney Disease

Limited instruments are available to determine diet quality among US adults with chronic kidney disease (CKD). The purpose of this study was two-fold: (1) to develop a food frequency questionnaire, CKD SFFQ, for adults with CKD and (2) to validate the CKD SFFQ against two 24-h recalls in determining diet quality (DQ). A 57-item CKD SFFQ was developed through a content validation method. Adults with CKD (n = 46) completed the CKD SFFQ and 2-24-h recalls. Statistical analyses included descriptive statistics, frequencies, t-tests, Pearson correlations, and Bland-Altman plots. All data were analyzed using JMP SAS v15 with statistical significance detected at p < 0.05. Results showed no differences for the overall DQ (p = 0.11) and the nine whole-food components (p = 0.07 to p = 0.44) when comparing the CKD SFFQ to the 2-24-h recalls. Pearson correlation coefficients ranged from -0.39 (refined grains) to 0.60 (greens and beans). Bland-Altman plots showed overall good agreement and there was a systematic trend towards higher estimates with the CKD SFFQ, particularly for overall DQ, total proteins, and dairy. The majority of participants rarely or never consumed grains, fruits, vegetables, seafood, and plant proteins. The CKD SFFQ was demonstrated to be an acceptable method to determine DQ for adults with CKD.

Bee bread mitigates downregulation of steroidogenic genes, decreased spermatogenesis, and epididymal oxidative stress in male rats fed with high-fat diet

The pituitary-gonadal axis plays an important role in steroidogenesis and spermatogenesis, and by extension, fertility. The aim of this study was to investigate the protective role of bee bread, a natural bee product, against obesity-induced decreases in steroidogenesis and spermatogenesis. Thirty-two adult male Sprague-Dawley rats weighing between 200 and 300 g were divided into four groups (n = 8/group), namely: normal control (NC), high-fat diet (HFD), HFD plus bee bread administered concurrently for 12 wk (HFD + B), HFD plus orlistat administered concurrently for 12 wk (HFD + O) groups. Bee bread (0.5 g/kg) or orlistat (10 mg/kg/day) was suspended in distilled water and given by oral gavage daily for 12 wk. Levels of follicle-stimulating hormone, luteinizing hormone, testosterone, and adiponectin, as well as sperm count, motility, viability, normal morphology, and epididymal antioxidants decreased, whereas levels of leptin, malondialdehyde, and sperm nDNA fragmentation increased significantly in the HFD group relative to the NC group. There were significant decreases in the testicular mRNA transcript levels of androgen receptor, luteinizing hormone receptor, steroidogenic acute regulatory protein, cytochrome P450 enzyme, 3β-hydroxysteroid dehydrogenase (HSD) and 17β-HSD in the testes of the HFD group. Furthermore, mount, intromission and ejaculatory latencies increased, and penile cGMP level decreased significantly in the HFD group. Supplementation with bee bread significantly reduced leptin level and increased adiponectin level, enhanced sperm parameters and reduced sperm nDNA fragmentation, upregulated the levels of steroidogenic genes and proteins in HFD-induced obese male rats. Bee bread improved steroidogenesis and spermatogenesis by upregulating steroidogenic genes. Therefore, bee bread may be considered as a potential supplementation to protect against infertility in overweight men or men with obesity.NEW & NOTEWORTHY The high-fat diet utilized in the present study induced obesity in the male rats. Bee bread supplementation mitigated impaired steroidogenesis, spermatogenesis, mating behavior, and fertility potential by counteracting the downregulation of steroidogenic genes, thus increasing testosterone levels and suppressing epididymal oxidative stress. These benefits may be due to the abundance of phenolic and flavonoid compounds in bee bread.

Sirtuins and Renal Oxidative Stress

Renal failure is a major health problem that is increasing worldwide. To improve clinical outcomes, we need to understand the basic mechanisms of kidney disease. Aging is a risk factor for the development and progression of kidney disease. Cells develop an imbalance of oxidants and antioxidants as they age, resulting in oxidative stress and the development of kidney damage. Calorie restriction (CR) is recognized as a dietary approach that promotes longevity, reduces oxidative stress, and delays the onset of age-related diseases. Sirtuins, a type of nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylase, are considered to be anti-aging molecules, and CR induces their expression. The sirtuin family consists of seven enzymes (Sirt1–7) that are involved in processes and functions related to antioxidant and oxidative stress, such as DNA damage repair and metabolism through histone and protein deacetylation. In fact, a role for sirtuins in the regulation of antioxidants and redox substances has been suggested. Therefore, the activation of sirtuins in the kidney may represent a novel therapeutic strategy to enhancing resistance to many causative factors in kidney disease through the reduction of oxidative stress. In this review, we discuss the relationship between sirtuins and oxidative stress in renal disease.

New Pandemic: Obesity and Associated Nephropathy

Incidence of obesity related renal disorders have increased 10-folds in recent years. One of the consequences of obesity is an increased glomerular filtration rate (GFR) that leads to the enlargement of the renal glomerulus, i.e., glomerulomegaly. This heightened hyper-filtration in the setting of type 2 diabetes irreparably damages the kidney and leads to progression of end stage renal disease (ESRD). The patients suffering from type 2 diabetes have progressive proteinuria, and eventually one third of them develop chronic kidney disease (CKD) and ESRD. For ameliorating the progression of CKD, inhibitors of renin angiotensin aldosterone system (RAAS) seemed to be effective, but on a short-term basis only. Long term and stable treatment strategies like weight loss via restricted or hypo-caloric diet or bariatric surgery have yielded better promising results in terms of amelioration of proteinuria and maintenance of normal GFR. Body mass index (BMI) is considered as a traditional marker for the onset of obesity, but apparently, it is not a reliable indicator, and thus there is a need for more precise evaluation of regional fat distribution and amount of muscle mass. With respect to the pathogenesis, recent investigations have suggested perturbation in fatty acid and cholesterol metabolism as the critical mediators in ectopic renal lipid accumulation associated with inflammation, increased generation of ROS, RAAS activation and consequential tubulo-interstitial injury. This review summarizes the renewed approaches for the obesity assessment and evaluation of the pathogenesis of CKD, altered renal hemodynamics and potential therapeutic targets.

Hypertension and obesity in living kidney donors

Over the past few decades, the shortage in the kidney donor pool as compared to the increasing number of candidates on the kidney transplant waitlist led to loosening of kidney donors' acceptance criteria. Hypertension and obesity represent risk factors for chronic kidney disease, both in native kidneys and those in kidney transplant recipients. While great progress has been made in kidney transplantation from living donors to benefit the recipient survival and quality of life, progress has been slow to fully risk-characterize the donors. This review critically reassesses the current state of understanding regarding the risk of end-stage kidney disease in those donors with obesity, hypertension or both. Accurate risk assessment tools need to be developed urgently to fully understand the risk glomerular filtration rate compensation failure in the remaining kidney of the donors.

Agomelatine protects against obesity-induced renal injury by inhibiting endoplasmic reticulum stress/apoptosis pathway in rats

Obesity is recognized as a risk for the development of chronic kidney disease. Excessive fat accumulation in obesity is associated with the overproduction of reactive oxygen species with the underproduction of antioxidant mechanisms generating oxidative stress together with chronic low-grade inflammation which subsequently leads to the development of several obesity-related complications. It has been suggested that the abnormal lipid accumulation can induce endoplasmic reticulum (ER) stress and cellular apoptosis in several tissue types. Agomelatine is a relatively new antidepressant which is a synthetic agonist of melatonin. Previous study reported the antioxidant and anti-inflammatory effects of agomelatine. In this study, we investigated the therapeutic effects of agomelatine in obesity-related renal injury. Male Wistar rats were fed with normal diet or high-fat diet (HF) for 16 weeks. After that, vehicle or agomelatine or vildagliptin was orally administered to HF rats for 4 weeks. Our results indicated that HF rats demonstrated insulin resistance which was accompanied by an impairment of renal function and renal organic anion transporter 3 (Oat3) function as well as renal oxidative stress, ER stress, and apoptosis. Interestingly, agomelatine treatment not only improved the metabolic parameters, renal function and renal Oat3 function but also attenuated renal oxidative stress, ER stress and subsequent apoptosis. Therefore, agomelatine exerted renoprotective effects in obese insulin-resistant condition. These results suggested that agomelatine could be used as a drug to improve metabolic disturbance and prevent kidney dysfunction in obese condition.

Impact of adipose tissue in chronic kidney disease development (Review)

Obesity is a worldwide pandemic health issue. Obesity is associated with the pathogenesis of type 2 diabetes, hypertension, dyslipidemia, cardiovascular diseases, cancer, and kidney diseases. This systemic disease can affect the kidneys by two mechanisms: Indirectly through diabetes mellitus (DM) and hypertension and directly through adipokines secreted by adipose tissue. Obesity is a risk factor for chronic kidney disease (CKD), which is associated with an increased risk of morbidity and mortality among the adult population. Increased visceral adipose tissue leads to renal glomerular hyperfiltration and hyperperfusion, which may lead to glomerular hypertrophy, proteinuria, and CKD development. Adipokines are hormones produced by fat tissue. They are involved in energy homeostasis, sugar and fat metabolism, reproduction, immunity, and thermogenesis control. Hormones and cytokines secreted by adipose tissue contribute to the development and progression of CKD. Decreased serum or urinary adiponectin levels are specific in diabetic and non-diabetic CKD patients, while leptin presents increased levels, and both are associated with the development of glomerulopathy. Excessive adipose tissue is associated with inflammation, oxidative stress (OS), insulin resistance and activation of the renin angiotensin-aldosterone system (RAAS). Therefore, adipose tissue dysfunction plays an important role in the development of CKD.

Obesity measures at baseline, their trajectories over time, and the incidence of chronic kidney disease: A 14 year cohort study among Korean adults

BACKGROUND AND AIMS

We investigated the association of baseline obesity measures, i.e. body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist-hip ratio (WHR), and their trajectories over time with incident chronic kidney disease (CKD).

METHODS AND RESULTS

Utilizing data from 2001 to 2014 for 9796 Korean adults without CKD at baseline, the association of baseline obesity measures with incident CKD was evaluated using logistic regression. Further, among 5605 subjects with repeated measures, the effect of the trajectories in obesity measures on CKD incidence was investigated via Cox regression. Baseline obesity in terms of BMI, WC, and HC increased the odds of incident CKD (odds ratio (OR) 1.19, 95% confidence interval (CI) 1.05-1.33; OR 1.22, 95% CI 1.07-1.38; and OR 1.25, 95% CI 1.11-1.41, respectively), while baseline WHR did not show such an association. A "became non-obese" BMI, WC, or WHR trajectory, and a "constantly not large" HC trajectory decreased the hazard of incident CKD (hazard ratio (HR) 0.70, 95% CI 0.50-0.99; HR 0.61, 95% CI 0.40-0.92; HR 0.55, 95% CI 0.35-0.85; and HR 0.81, 95% CI 0.69-0.95, respectively) when compared with a "constantly obese or became obese" trajectory.

CONCLUSION

Both baseline obesity and obesity trajectories over time were associated with CKD incidence. BMI and WC were equally good measures of CKD risk, while WHR was not. Separately examining WC and HC components of WHR (= WC/HC) may explain WHR's inconsistency, and WHR's usefulness as a measure of CKD risk should be reevaluated.

Obesity as a Risk Factor for Radiographic Contrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is common. Risk factors include preexisting renal impairment, diabetes, elderly age, and dehydration. In a single-centre prospective study, we investigated which factors are implicated for CIN in patients with peripheral arterial disease due for angiography. Serum creatinine was measured before, 1, 2, and 7 days post-angiography. We also considered the chronic kidney disease stage of the patients at admission and 48 hours post-contrast. All patients received 500 mL normal saline pre- and post-angiography and a low-osmolality contrast medium. 6 of 94 patients developed CIN: 1 required dialysis and 1 died partly due to renal failure. Only 2 factors were associated with CIN: body mass index (BMI; P = .019) and kidney function (P = .001); 4 of 6 patients with CIN were obese (BMI ≥30) and only 2 were nonobese (P = .0092). Diabetes, contrast volume, and age were not significant risk factors. Our results confirm renal impairment raises the risk of CIN. To our knowledge, we report for the first time that obesity may be a risk factor for CIN. Pending confirmatory studies and given the rising prevalence of obesity, this finding could help identify at-risk patients and hence reduce the burden of CIN.

Effect of spexin on renal dysfunction in experimentally obese rats: potential mitigating mechanisms via galanin receptor-2

This study declared effect of spexin (SPX) on renal dysfunction in obese rats and its potential mitigating mechanisms which could mediated via galanin receptor-2 (GALR-2). Thirty two 32 Wistar male rats were arranged into four groups: control, high fat/fructose diet (HFFD), HFFD + SPX and HFFD + M871 (galanin receptor 2 antagonist)+SPX. At the termination of the experiment, urine volume, body mass index, Lee index and mean arterial blood pressure were assessed. Renal function was evaluated. Lipid profile, fasting glucose, insulin, insulin resistance and SPX levels were estimated. Also, renal histopathological, immunohistochemical and relative gene expression of renal tissue were done. Also, renal protein carbonyl, reduced glutathione, interferon gamma, monocyte chemoattractant protein-1, interleukin-10 and hydroxyproline were determined.Our results explored that SPX treatment prominently mitigated the metabolic changes and renal dysfunction induced by HFFD via GALR-2. SPX improved insulin resistance, dyslipidemia, renal oxidative stress, inflammation, apoptosis, and fibrosis. So, SPX can be considered as prospective therapeutic agent for treating renal dysfunction.

Selenium, Zinc, Chromium, and Vanadium Levels in Serum, Hair, and Urine Samples of Obese Adults Assessed by Inductively Coupled Plasma Mass Spectrometry

The objective of this study was to investigate of selenium (Se), zinc (Zn), chromium (Cr), and vanadium (V) levels in blood serum, hair, and urine of adult obese patients. A total of 199 lean and 196 obese subjects were enrolled in the study. Serum, hair, and urinary metal and metalloid analysis were performed by inductively coupled plasma mass spectrometry at NexION 300D (PerkinElmer Inc., USA). The results established that obese subjects were characterized by 47% and 30% lower serum Cr and V levels compared with controls, respectively, whereas serum Se levels exceeded control values by 9%. In contrast, hair Cr, Se, and V content in obese subjects exceeded the control values by 51%, 21%, and 50%, respectively. In turn, hair Zn levels were found to be significantly lower by 11% compared with the lean control values. In urine, the levels of V and Zn were found to be 30% and 18% higher in obese patients. Prevalence of hypertension in obese subjects was associated with a trend for impaired Se and Zn levels. In a regression model adjusted for age, gender, hypertension, atherosclerosis, and glucose intolerance, serum Cr, V, and hair Zn were inversely associated with body mass index (BMI), whereas hair Se was considered as the positive predictor. Our data allow proposing that the observed alterations may at least partially contribute to metabolic disturbances in obesity. In turn, monitoring of Se exposure in a well-nourished adult population is required to reduce its potential contribution to obesity.

Diabetes, Hypertension, Obesity, and Smoking as Risk Factors for Chronic Kidney Disease in Productive Age

Background: Based on the Indonesia basic health research report in 2018, the prevalence of chronic kidney disease (CKD) in the productive age group in Indonesia had increased from the previous year, to 1.97%. This condition can cause various complications that contribute to the high morbidity, which affects quality of life and productivity, so risk factors for CKD need to be understood to prevent the occurrence of the disease. Purpose: This study aimed to analyze the risk factors associated with CKD in the Indonesian productive-age population. Method: This study used data sourced from Indonesian Family Life Survey 5 (IFLS-5) with a cross-sectional research design. The study population was composed of all Indonesian residents who were respondents of IFLS-5. The research sample was made up of respondents aged 15–64 for whom complete information was available. The sample size was 29,120 respondents. The variables analyzed in this study were diabetes, hypertension, obesity, smoking, and CKD. The analysis method used was the chi-square test. Results: Bivariate analysis showed a significant relationship between CKD and diabetes (p = 0.01; prevalence ratio [PR] = 2.71; 95% CI = 1.74–4.22), hypertension (p = 0.01; PR = 2.62; 95% CI = 2.08–3.30), obesity (p = 0.01; PR = 1.67; 95% CI = 1.25–2.23), and smoking (p = 0.01; PR = 1.43; 95% CI = 1.17–1.75) in the productive age group in Indonesia. Conclusion: Diabetes, hypertension, obesity, and smoking have a significant relationship with CKD in the productive age group in Indonesia.

Rice bran modulates renal disease risk factors in animals submitted to high sugar-fat diet

Introduction:

Obesity, diabetes, and hypertension are common risk factors for chronic kidney disease (CKD). CKD arises due to many pathological insults, including inflammation and oxidative stress, which affect renal function and destroy nephrons. Rice bran (RB) is rich in vitamins and minerals, and contains significant amount of antioxidants. The aim of this study was to evaluate the preventive effect of RB on renal disease risk factors.

Methods:

Male Wistar rats (±325 g) were divided into two experimental groups to received a high sugar-fat diet (HSF, n = 8) or high sugar-fat diet with rice bran (HSF + RB, n = 8) for 20 weeks. At the end, renal function, body composition, metabolic parameters, renal inflammatory and oxidative stress markers were analyzed.

Results:

RB prevented obesity [AI (HSF= 9.92 ± 1.19 vs HSF + RB= 6.62 ± 0.78)], insulin resistance [HOMA (HSF= 83 ± 8 vs. HSF + RB= 42 ± 11)], dyslipidemia [TG (HSF= 167 ± 41 vs. HSF + RB=92 ± 40)], inflammation [TNF-α (HSF= 80 ± 12 vs. HSF + RB=57 ± 14), IL-6 (903 ± 274 vs. HSF + RB=535 ± 277)], oxidative stress [protein carbonylation (HSF= 3.38 ± 0.18 vs. HSF + RB=2.68 ± 0.29), RAGE (HSF=702 ± 36 vs. RSF + RB=570 ± 190)], and renal disease [protein/creatinine ratio (HSF=1.10 ± 0.38 vs. HSF + RB=0.49 ± 0.16)].

Conclusion:

In conclusion, rice bran prevented renal disease by modulating risk factors.

Gender difference in the association of chronic kidney disease with visceral adiposity index and lipid accumulation product index in Korean adults: Korean National Health and Nutrition Examination Survey

BACKGROUND

This study was conducted to assess gender difference in the association of chronic kidney disease (CKD) with visceral adiposity index (VAI) and lipid accumulation product index (LAP) in Korean adults.

MATERIALS AND METHODS

The study was performed using data from the 2015 Korean National Health and Nutrition Examination Survey and included 4947 adults aged 20 years or older.

RESULTS

There were several key findings in the present study. First, overall, after adjusting for related variables (including age), CKD (estimated glomerular filtration rate < 60 ml/min/1.73 m²) was positively associated with the quartiles of VAI and LAP. Second, when analyzed separately for gender, the results in men and women were different. After adjusting for the related variables (except age), CKD was positively associated with the quartiles of VAI and LAP in both men and women. After further adjustment for age, CKD was still positively associated with the quartiles of VAI and LAP in men. However, in women, the relationships between CKD and the quartiles of VAI and LAP were no longer significant.

CONCLUSIONS

The VAI and LAP index were positively associated with CKD in Korean men but not in women.

Saturated fatty acids induce insulin resistance in podocytes through inhibition of IRS1 via activation of both IKKβ and mTORC1

Diabetic nephropathy (DN), a microvascular complication of diabetes, is the leading cause of end-stage renal disease worldwide. Multiple studies have shown that podocyte dysfunction is a central event in the progression of the disease. Beside chronic hyperglycemia, dyslipidemia can induce insulin resistance and dysfunction in podocytes. However, the exact mechanisms of free fatty acid (FFA)-induced podocyte insulin unresponsiveness are poorly understood. We used a type 2 diabetic mouse model (db/db) and mouse podocytes exposed to palmitic acid for 24 h followed by an insulin stimulation. Renal function and pathology were evaluated at 25 weeks of age to confirm the DN development. Our results demonstrate that saturated FFA activated the serine/threonine kinases IκB kinase (IKK)β/IκBα and mTORC1/S6K1, but not protein kinase C and c-jun N-terminal kinase, in podocytes and glomeruli of db/db mice. Activation of both kinases promoted serine 307 phosphorylation of IRS1, a residue known to provoke IRS1 inhibition. Using IKK, mTORC1 and ceramide production inhibitors, we were able to blunt IRS1 serine 307 phosphorylation and restore insulin stimulation of Akt. In conclusion, our results indicate that FFA and diabetes contribute to insulin resistance through the activation of IKKβ and S6K1 leading to podocyte dysfunction and DN.

Treatment With Gemfibrozil Prevents the Progression of Chronic Kidney Disease in Obese Dahl Salt-Sensitive Rats

Recently, we reported that Dahl salt-sensitive leptin receptor mutant (SS^LepRmutant) rats exhibit dyslipidemia and renal lipid accumulation independent of hyperglycemia that progresses to chronic kidney disease (CKD). Therefore, in the current study, we examined the effects of gemfibrozil, a lipid-lowering drug (200 mg/kg/day, orally), on the progression of renal injury in SS and SS^LepRmutant rats for 4 weeks starting at 12 weeks of age. Plasma triglyceride levels were markedly elevated in the SS^LepRmutant strain compared to SS rats (1193 ± 243 and 98 ± 16 mg/day, respectively). Gemfibrozil treatment only reduced plasma triglycerides in the SS^LepRmutant strain (410 ± 79 mg/dL). MAP was significantly higher in the SS^LepRmutant strain vs. SS rats at the end of the study (198 ± 7 vs. 165 ± 7 mmHg, respectively). Administration of gemfibrozil only lowered MAP in SS^LepRmutant rats (163 ± 8 mmHg). During the course of the study, proteinuria increased to 125 ± 22 mg/day in SS rats. However, proteinuria did not change in the SS^LepRmutant strain and remained near baseline (693 ± 58 mg/day). Interestingly, treatment with gemfibrozil increased the progression of proteinuria by 77% in the SS^LepRmutant strain without affecting proteinuria in SS rats. The renal injury in the SS^LepRmutant strain progressed to CKD. Moreover, the kidneys from SS^LepRmutant rats displayed significant glomerular injury with mesangial expansion and increased renal lipid accumulation and fibrosis compared to SS rats. Treatment with gemfibrozil significantly reduced glomerular injury and lipid accumulation and improved renal function. These data indicate that reducing plasma triglyceride levels with gemfibrozil inhibits hypertension and CKD associated with obesity in SS^LepRmutant rats.

Cross-shift change of acute kidney injury biomarkers in sugarcane farmers and cutters

Sugarcane farmers and cutters have been reported to be at high risk of acute kidney injury. This cross-sectional study aimed to assess acute kidney injury biomarkers, and cross-shift change among 150 sugarcane cutters and 98 sugarcane farmers in Thailand. Physical health examination, environmental measurements, and measured urinary neutrophil gelatinase-associated lipocalin (NGAL) were assessed. Cross-shift change of urine creatinine (uCr), albumin creatinine ratio (ACR), and NGAL between sugarcane farmers and cutters was compared. Factors influencing abnormal post-shift ACR and NGAL were analyzed by binary logistic regression adjusted with covariates. Sugarcane cutters were significantly more likely to take nonsteroidal anti-inflammatory drugs (NSAID) and herbs to relieve pain than sugarcane farmers. Males were more likely to be current smokers and drinkers although 62% of cutters and 56% of farmers were female. Sugarcane farmers and cutters had similar post-shift estimated glomerular filtration rate (eGFR) and ACR levels. Cross-shift measurements showed that both sugarcane cutters and sugarcane farmers had significantly higher post-shift geometric mean (GM) urinary NGAL, but that the cross-shift changes of NGAL were significantly higher for sugarcane cutters (182%) vs. sugarcane farmers (112%). Water intake less than recommendation of subjects was a significant predictor of a higher risk for an abnormal post-shift ACR after controlling for covariates, while being a sugarcane cutter was a predictor of a lower risk of an abnormal risk of a post-shift NGAL after controlling for covariates. Measurements of heat stress (WBGT plus workload) found that sugarcane cutters exceeded recommended exposures while sugarcane farmers were compliance to the TLV. These findings suggest that to protect sugarcane farmers and cutters, preventative measures are needed.

Bariatric Surgery Improves Renal Function: a Large Inner-City Population Outcome Study

BACKGROUND

Bariatric surgery is associated with improved renal dysfunction in general population studies. The study examined the effects of bariatric surgery on renal function in a predominantly Hispanic and African American population at a community hospital in New York, USA.

METHODS

This retrospective study analyzed prospectively collected bariatric surgical data from 2247 patients (89% female) who underwent bariatric surgery at a single center. Changes in glomerular filtration rate (eGFR), urine albumin-creatinine ratio (UACR), micro- and macroalbuminuria, and hyperfiltration, which were measured preoperatively and then yearly for 3 years postoperatively, were evaluated with t tests and logistic regression analysis, after adjusting for confounding variables. The mean age of the patients at surgery was 37.1 years; the mean preoperative body mass index was 45 ± 7 kg/m².

RESULTS

The results obtained 3 years postoperatively showed the following significant improvements compared with the preoperative values: mean UACR decreased from 40.3 to 11.1 mg/g, mean eGFR improved from 79.4 to 87.3 mL/min, the prevalence of microalbuminuria decreased from 13.7 to 6.2%, the prevalence of macroalbuminuria decreased from 2.5 to 0%, and the prevalence of hyperfiltration decreased from 4.4 to 2.7% (all P < .0001). In adjusted multivariate regression analysis, these results remained significant after adjusting for age, sex, race, type of surgery, and presence of diabetes mellitus or hypertension.

CONCLUSION

In this large study at an inner-city hospital, bariatric surgery was associated with significant improvements in renal dysfunction parameters. These results could assist with informed decisions regarding indications for bariatric surgery.

Association of Pulmonary Hypertension With End-Stage Renal Disease Among the Obese Population

Introduction

Pulmonary hypertension (PH) is a known complication that occurs in patients of end-stage renal disease (ESRD) that have an arteriovenous fistula (AVF) for hemodialysis (HD). It is defined as pulmonary artery pressure (PAP) of greater than 30 mmHg on echocardiography. The presence of PH in ESRD is an independent risk factor and decreases the survival likelihood among HD patients. Unexplained PH is frequently seen in ESRD following AVF.

Obesity can lead to various complications, such as sleep apnea, cardiac complications, pulmonary hypertension, and mortality. Data on the prevalence of coexisting PH and obesity are scarce.

Obese patients often have increased albumin excretion rates (AER) that can lead to early renal impairment and an increase in intraglomerular pressure, which may increase the risk of cardiovascular (CV) morbidity and mortality.

Therefore, the study aimed to evaluate and compare the associated PH and obesity separately and collectively among ESRD patients.

Methods

This comparative cross-sectional study was conducted in a tertiary care public sector hospital with the approval of the medical ethics review board committee.

The study enrolled all consecutive patients with ESRD as defined by having an estimated glomerular filtration rate (GFR) of <15 mL/min/1.7 3 m² from April 2017 till March 2019, who presented to our facility. These patients underwent dialysis twice or thrice a week, each session lasting three to four hours approximately. On initial encounter, trans-thoracic echocardiography (TTE) was done by the cardiologist to diagnose pulmonary hypertension.

In addition, body mass index (BMI) was calculated for all patients, and the patients were categorized into underweight, normal, overweight, or obese. All patients underwent post-dialysis TTE at one hour or when patients were at the optimal dry weight. Systolic PAP and ejection fraction were measured, and pulmonary hypertension was defined as a PAP of 30 mmHg or greater on TTE.

ESRD patients that were diagnosed with PH prior to hemodialysis or had primary PH were excluded from the study. Only ESRD patients developing secondary PH after hemodialysis were included in the study.

The chi-square test was used to see the correlation of gender, ambulation status, smoking status, obesity, pulmonary hypertension, body mass index (BMI), and pulmonary hypertension and obesity combined on the final outcome. A p-value of 0.05 was considered significant. Odds ratio (OR) and relative risk (RR) were calculated for pulmonary hypertension and obesity combined, obesity, and pulmonary hypertension in the final outcome.

Results

The study enrolled 204 patients with a mean age of 46.23 (±20.45 SD) having higher female participation of 108 (52.9%), whereas 96 (47.1%) were males. The average weight of the cohort was 66.78 kg (±22.98 SD) with a mean BMI of 29.91 kg/m² (±13.29SD), 52 (25.5%) patients were underweight, 40 (19.6%) had a normal BMI, 29 (14.2%) were overweight, and 83 (40.7%) patients were obese.

Pulmonary hypertension and obesity combined were observed in 48 (23.5%) of the cases and there was a 4.60 relative risk of death among these individuals, with an odds ratio of 13.35 and a p-value of 0.00.

Conclusion

The study shows a strong synergistic effect of pulmonary hypertension and obesity towards the final survival outcome in ESRD patients who are on hemodialysis.

The effect of type 2 diabetes diagnosis in the elderly

In this paper, I use a novel approach based on biomarkers data to examine the effect of type 2 diabetes (T2D) diagnosis on both physical and mental health for a sample of individuals aged 50 and above. In order to retrieve reliable estimates, I exploit the fact that medical guidelines cause a discontinuity in the probability that General Practitioners (GP) diagnose their patients with T2D as a function of exact blood test cut-off in a regression discontinuity design (RDD) approach. Using data from the English Longitudinal Study of Ageing (ELSA), I find compelling evidence that health information, in the form of T2D diagnosis, influences the protection of health into old age. Specifically, after receiving T2D diagnosis, over time, individuals reported a 2.1 lower body mass index (BMI) as well as 5.5 cm lower waist circumference, relative to their counterparts. With respect to self-reported physical health, the results imply that those diagnosed with T2D reported a 0.19 and 0.70 higher score in increased activities of daily living (ADL) and body mobility indexes, respectively. Finally, while I find evidence that T2D-diagnosed patients reported a significant, 0.5 higher, score in the word listening test, I find no evidence that T2D diagnosis impacted self-reported depression levels. I provide a wide variety of evidence on the validity of the results.

The effect of a multidisciplinary weight loss program on renal circadian rhythm in obese adolescents

Adolescent obesity is a serious health problem associated with many comorbidities. Obesity-related alterations in circadian rhythm have been described for nocturnal blood pressure and for metabolic functions. We believe renal circadian rhythm is also disrupted in obesity, though this has not yet been investigated. This study aimed to examine renal circadian rhythm in obese adolescents before and after weight loss.In 34 obese adolescents (median age 15.7 years) participating in a residential weight loss program, renal function profiles and blood samples were collected at baseline, after 7 months, and again after 12 months of therapy. The program consisted of dietary restriction, increased physical activity, and psychological support. The program led to a median weight loss of 24 kg and a reduction in blood pressure. Initially, lower diurnal free water clearance (- 1.08 (- 1.40-- 0.79) mL/min) was noticed compared with nocturnal values (0.75 (- 0.89-- 0.64) mL/min). After weight loss, normalization of this inverse rhythm was observed (day - 1.24 (- 1.44-1.05) mL/min and night - 0.98 (- 1.09-- 0.83) mL/min). A clear circadian rhythm in diuresis rate and in renal clearance of creatinine, solutes, sodium, and potassium was seen at all time points. Furthermore, we observed a significant increase in sodium clearance. Before weight loss, daytime sodium clearance was 0.72 mL/min (0.59-0.77) and nighttime clearance was 0.46 mL/min (0.41-0.51). After weight loss, daytime clearance increased to 0.99 mL/min (0.85-1.17) and nighttime clearance increased to 0.78 mL/min (0.64-0.93).Conclusion: In obese adolescents, lower diurnal free water clearance was observed compared with nocturnal values. Weight loss led to a normalization of this inverse rhythm, suggesting a recovery of the anti-diuretic hormone activity. Both before and after weight loss, clear circadian rhythm of diuresis rate and renal clearance of creatinine, solutes, sodium, and potassium was observed.What is Known:• Obesity-related alterations in circadian rhythm have been described for nocturnal blood pressure and for metabolic functions. We believe renal circadian rhythm is disrupted in obesity, though this has not been investigated yet.What is New:• In obese adolescents, an inverse circadian rhythm of free water clearance was observed, with higher nighttime free water clearance compared with daytime values. Weight loss led to a normalization of this inverse rhythm, suggesting a recovery of the anti-diuretic hormone activity.• Circadian rhythm in diuresis rate and in the renal clearance of creatinine, solutes, sodium, and potassium was preserved in obese adolescents and did not change after weight loss.

Obese trauma patients have increased need for dialysis

PURPOSE

Obesity is a risk factor for the development of acute kidney injury but its effect on the need for dialysis in trauma has not been elucidated. Additionally, the contribution that obesity has towards risk of mortality in trauma is unclear. We hypothesized that patients with a higher body mass index (BMI) will have a higher risk for need of dialysis and mortality after trauma.

METHODS

This is a retrospective analysis using the National Trauma Data Bank. All patients ≥ 8 years old were grouped based on BMI: normal (18.5-24.99 kg/m²), obese (30-34.99 kg/m²), severely obese (35-39.99 kg/m²) and morbidly obese (≥ 40 kg/m²). The primary outcome was hemodialysis initiation. The secondary outcome was mortality during the index hospitalization.

RESULTS

From 988,988 trauma patients, 571,507 (57.8%) had a normal BMI, 233,340 (23.6%) were obese, 94,708 (9.6%) were severely obese, and 89,433 (9.0%) were morbidly obese. The overall rate of hemodialysis was 0.3%. After adjusting for covariates, we found that obese (OR 1.36, CI 1.22-1.52, p < 0.001), severely obese (OR 1.89, CI 1.66-2.15, p < 0.001) and morbidly obese (OR 2.04, CI 1.82-2.29, p < 0.001) patients had a stepwise increased need for hemodialysis after trauma. Obese patients had decreased (OR 0.92, CI 0.88-0.95, p < 0.001), severely obese had similar (OR 1.02, CI 0.97-1.08, p = 0.50) and morbidly obese patients had increased (OR 1.06, CI 1.01-1.12, p = 0.011) risk of mortality after trauma.

CONCLUSIONS

Obesity was associated with an increased risk for dialysis after trauma. Mortality risk was reduced in obese, similar in severely obese, and increased in morbidly obese trauma patients suggesting an inflection threshold BMI for risk of mortality in trauma.

Oxidative Imbalance and Kidney Damage in Cafeteria Diet-Induced Rat Model of Metabolic Syndrome: Effect of Bergamot Polyphenolic Fraction

Obesity is a potent risk factor for kidney disease as it increases the possibility of developing diabetes and hypertension, and it has a direct impact on the development of chronic kidney disease and end-stage renal disease. In this study, we tested the effect of bergamot polyphenolic fraction in a cafeteria with diet-fed rats, an excellent experimental model for studying human metabolic syndrome, as it is able to induce severe obesity with insulin resistance and high plasma triglyceride levels more efficiently than a traditional lard-based high-fat diet used in rodent models. We analyzed the plasmatic oxidative balance by photometric tests, and the expression of cytoplasmic antioxidant enzymes (superoxide dismutase 1 and glutatione S-tranferasi P1) and apoptotic markers (Caspase 8 and 9) in kidney tissues by Western blot analysis. Our results clearly showed that the cafeteria diet induces a marked pro-oxidant effect: significant reduction of plasmatic antioxidant capacity; downregulation of cytoplasmic antioxidant enzymes expression; and activation of apoptotic pathways. All these hallmarks of redox disequilibrium were mitigated by treatment with polyphenolic fraction of bergamot, highlighting its antioxidant effect in the metabolic syndrome. Our data show that the link between obesity and renal damage could be represented by oxidative stress.

Role of connecting tubule glomerular feedback in obesity related renal damage

Zucker obese rats (ZOR) have higher glomerular capillary pressure (P_GC) that can cause renal damage. P_GC is controlled by afferent (Af-Art) and efferent arteriole (Ef-Art) resistance. Af-Art resistance is regulated by factors that regulate other arterioles, such as myogenic response. In addition, it is also regulated by 2 intrinsic feedback mechanisms: 1) tubuloglomerular feedback (TGF) that causes Af-Art constriction in response to increased NaCl in the macula densa and 2) connecting tubule glomerular feedback (CTGF) that causes Af-Art dilatation in response to an increase in NaCl transport in the connecting tubule via the epithelial sodium channel. Since CTGF is an Af-Art dilatory mechanism, we hypothesized that increased CTGF contributes to TGF attenuation, which in turn increases P_GC in ZOR. We performed a renal micropuncture experiment and measured stop-flow pressure (P_SF), which is an indirect measurement of P_GC in ZOR. Maximal TGF response at 40 nl/min was attenuated in ZOR (4.47 ± 0.60 mmHg) in comparison to the Zucker lean rats (ZLR; 8.54 ± 0.73 mmHg, P < 0.05), and CTGF was elevated in ZOR (5.34 ± 0.87 mmHg) compared with ZLR (1.12 ± 1.28 mmHg, P < 0.05). CTGF inhibition with epithelial sodium channel blocker normalized the maximum P_SF change in ZOR indicating that CTGF plays a significant role in TGF attenuation (ZOR, 10.67 ± 1.07 mmHg vs. ZLR, 9.5 ± 1.53 mmHg). We conclude that enhanced CTGF contributes to TGF attenuation in ZOR and potentially contribute to progressive renal damage.

Effect of Gamma-Oryzanol as Therapeutic Agent to Prevent Cardiorenal Metabolic Syndrome in Animals Submitted to High Sugar-Fat Diet

BACKGROUND

The high consumption of fat and sugar contributes to the development of obesity and co-morbidities, such as diabetes, and cardiovascular and kidney diseases. Different strategies have been used to prevent these diseases associated with obesity, such as changes in eating habits and/or the addition of dietary components with anti-inflammatory and anti-oxidant properties, such as gamma-oryzanol (γOz) present mainly in bran layers and rice germ.

METHODS

Animals were randomly divided into four experimental groups and fed ad libitum for 20 weeks with control diet (C, n = 8), control diet + γOz (C + γOz, n = 8), high-sugar and high-fat diet (HSF, n = 8), and high-sugar and high-fat diet + γOz (HSF + γOz, n = 8). HSF groups also received water + sucrose (25%). The dose of γOz was added to diets to reach 0.5% of final concentration (w/w). Evaluation in animals included food and caloric intake, body weight, plasma glucose, insulin, triglycerides, uric acid, HOMA-IR, glomerular filtration rate, protein/creatinine ratio, systolic blood pressure, and Doppler echocardiographic.

RESULTS

Animals that consumed the HSF diet had weight gain compared to group C, increased insulin, HOMA, glucose and triglycerides, there were also atrial and ventricular structural alterations, deterioration of systolic and diastolic function, decreased glomerular filtration rate, and proteinuria. Gamma-oryzanol is significantly protective against effects on body weight, hypertriglyceridemia, renal damage, and against structural and functional alteration of the heart.

CONCLUSION

Gamma-oryzanol shows potential as a therapeutic to prevent Cardiorenal Metabolic Syndrome.