Nicotine, smoking, podocytes, and diabetic nephropathy

Association of the interaction between interleukin-1β gene polymorphism and smoking status with the diabetic nephropathy risk in a Chinese Han population

OBJECTIVES

we aimed to evaluate the association of interleukin-1β (IL-1β) gene single nucleotide polymorphisms (SNPs) and its interaction with smoking status on diabetic nephropathy (DN) risk in a Chinese Han population.

METHODS

The Hardy-Weinberg equilibrium (HWE) was tested by using SNPStats ( https://www.snpstats.net/start.htm ), which was also used for testing the relationship between four SNPs and DN risk and haplotype analysis. The SNP- SNP and gene- smoking interaction were verified by using generalized multifactor dimensionality reduction (GMDR) model.

RESULTS

Logistic regression suggested that the DN risks of participants with rs16944- G allele were significantly higher than those with AA genotype, adjusted OR (95%CI) = 1.62 (1.24-2.01) for AG versus AA, 1.41 (0.75-2.12) for GG versus AA. Additionally, we also found that participants with rs3917356- T allele had an obviously higher DN risk than those with CC genotype, adjusted OR (95%CI) = 1.75 (1.34-2.19) for CT versus CC, 1.87 (1.23-2.54) for TT versus CC. GMDR model found a significant two-locus model (P = 0.011) including rs16944 and smoking. Compared with non- smokers with rs16944- AA genotype, smokers with rs1225404 AG or GG genotype had the highest DN risk after covariates adjustment, OR (95%CI) was 3.04 (1.98-4.12). We also found a haplotype containing rs1143634- T and rs3917356- T was associated with higher DN risk.

CONCLUSIONS

we found that the rs16944- G and rs3917356- T allele, interaction between rs16944 and smoking, haplotype containing rs1143634- T and rs3917356- T were all associated with increased DN risk.

Diabetic kidney disease and polymorphisms of the ELMO1 and AGTR1 genes: Systematic review

BACKGROUND

Diabetic kidney disease (DKD) is one of the main complications of diabetes, the main cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD) worldwide. The etiopathogenesis of DKD is complex and multifactorial; recently, genetic susceptibility has gained relevance since certain ethnicities, such as Native Americans and Mexican Americans, have a higher risk of developing this disease. Numerous studies have described that single nucleotide polymorphisms (SNPs), including those for ELMO1 and AGTR1 genes, could be associated with DKD.

OBJECTIVE

To carry out a systematic review of the scientific literature on the association of SNPs of the ELMO1 and AGTR1 gene with DKD in adult patients with type 2 diabetes mellitus (T2D).

METHODS

Systematic review in PubMed, Google Scholar, Worldwide Science, and Science Direct databases. The selection of publications was carried out following the guidelines proposed by PRISMA (Preferred Reporting Items for Systematic Reviews and Meta Analyses). Original articles that reported results in the adult population with T2D were included. Information about the allelic and genotypic frequencies of the SNPs and their association with DKD was obtained.

RESULTS

The polymorphisms most frequently associated with a DKD higher risk were rs741301, rs1345365, and rs10951509 for the ELMO1 gene, whereas the rs5186 and rs388915 for the AGTR1 gene.

CONCLUSION

The risk of developing DKD depends on several factors, including the genetic susceptibility conferred by the ELMO1 and AGTR1 gene polymorphisms, without ignoring the patient's lifestyle and environmental factors. The studies about these polymorphisms' association with DKD will allow a better understanding of non-modifiable risk factors for developing this disease and recognize the differences between different studied ethnicities, which would allow faster detection of patients with T2D susceptible to developing DKD, become early markers of kidney damage, as well as implementing preventive strategies on the most susceptible ethnicities.

Acid Sphingomyelinase and Ceramide Signaling Pathway Mediates Nicotine-Induced NLRP3 Inflammasome Activation and Podocyte Injury

Background: Recent studies have shown that Nlrp3 inflammasome activation is importantly involved in podocyte dysfunction induced by nicotine. The present study was designed to test whether acid sphingomyelinase (Asm) and ceramide signaling play a role in mediating nicotine-induced Nlrp3 inflammasome activation and subsequent podocyte damage. Methods and Results: Nicotine treatment significantly increased the Asm expression and ceramide production compared to control cells. However, prior treatment with amitriptyline, an Asm inhibitor significantly attenuated the nicotine-induced Asm expression and ceramide production. Confocal microscopic and biochemical analyses showed that nicotine treatment increased the colocalization of NLRP3 with Asc, Nlrp3 vs. caspase-1, IL-1β production, caspase-1 activity, and desmin expression in podocytes compared to control cells. Pretreatment with amitriptyline abolished the nicotine-induced colocalization of NLRP3 with Asc, Nlrp3 with caspase-1, IL-1β production, caspase-1 activity and desmin expression. Immunofluorescence analyses showed that nicotine treatment significantly decreased the podocin expression compared to control cells. However, prior treatment with amitriptyline attenuated the nicotine-induced podocin reduction. In addition, nicotine treatment significantly increased the cell permeability, O2 production, and apoptosis compared to control cells. However, prior treatment with amitriptyline significantly attenuated the nicotine-induced cell permeability, O2 production and apoptosis in podocytes. Conclusions: Asm is one of the important mediators of nicotine-induced inflammasome activation and podocyte injury. Asm may be a therapeutic target for the treatment or prevention of glomerulosclerosis associated with smoking.

High mobility group box 1 (HMGB1) mediates nicotine-induced podocyte injury

Introduction

Cigarette smoking is a well-established risk factor for renal dysfunction. Smoking associated with renal damage bears distinct physiological correlations in conditions such as diabetic nephropathy and obesity-induced glomerulopathy. However, the cellular and molecular basis of such an association remains poorly understood. High mobility group box 1(HMGB1) is a highly conserved non-histone chromatin associated protein that largely contributes to the pathogenesis of chronic inflammatory and autoimmune diseases such as sepsis, atherosclerosis, and chronic kidney diseases. Hence, the present study tested whether HMGB1 contributes to nicotine-induced podocyte injury.

Methods and Results

Biochemical analysis showed that nicotine treatment significantly increased the HMGB1 expression and release compared to vehicle treated podocytes. However, prior treatment with glycyrrhizin (Gly), a HMGB1 binder, abolished the nicotine-induced HMGB1 expression and release in podocytes. Furthermore, immunofluorescent analysis showed that nicotine treatment significantly decreased the expression of podocyte functional proteins- podocin and nephrin as compared to control cells. However, prior treatment with Gly attenuated the nicotine-induced nephrin and podocin reduction. In addition, nicotine treatment significantly increased desmin expression and cell permeability compared to vehicle treated podocytes. However, prior treatment with Gly attenuated the nicotine-induced desmin expression and cell permeability. Mechanistic elucidation revealed that nicotine treatment augmented the expression of toll like receptor 4 (TLR4) and pre-treatment with Gly abolished nicotine induced TLR4 upregulation. Pharmacological inhibition of TLR4 with Resatorvid, a TLR4 specific inhibitor, also attenuated nicotine induced podocyte damage.

Conclusion

HMGB1 is one of the important mediators of nicotine-induced podocyte injury through TLR4 activation.

Coffee intake, plasma caffeine levels, and diabetic microvascular complications: A Mendelian randomization study

BACKGROUND AND AIM

Diabetic microvascular complications pose significant health challenges for individuals. The influence of modifiable lifestyle factors, such as coffee intake, on these complications has not been conclusively determined, highlighting the need for a causality assessment.

METHODS AND RESULTS

Utilizing Mendelian randomization (MR), this study explored the causal links between coffee intake, plasma caffeine levels, and diabetic microvascular complications using data from FinnGen. Single nucleotide polymorphisms associated with coffee intake and plasma caffeine levels were identified through genome-wide association study meta-analyses. The univariable MR analysis indicated a slightly increased risk for diabetic retinopathy (OR 1.006; 95 % CI: 1.002-1.010; P = 0.003) and a suggestively elevated risk for nephropathy (OR 1.011; 95 % CI: 1.001-1.022; P = 0.036) associated with genetically predicted higher coffee intake, while no significant effect on neuropathy was observed. Multivariable MR analysis, adjusted for smoking, revealed a significant protective effect of coffee intake on diabetic retinopathy (OR 0.895; 95 % CI: 0.856-0.936; P = 9.468 × 10-7) and a suggestive reduction in risk for diabetic nephropathy (OR 0.828; 95 % CI: 0.712-0.963; P = 0.014). Higher plasma caffeine levels were also suggestively protective against these complications.

CONCLUSIONS

Our findings suggest that genetically predicted higher coffee intake and plasma caffeine levels are protective for diabetic retinopathy and nephropathy. Further research is necessary to substantiate these findings and to investigate their potential impact on diabetes management strategies.

Association Between Maternal Smoking, Isolated Proteinuria During Pregnancy and Preterm Birth: A Finnish Registry Analysis

Introduction

Smoking during pregnancy (SDP) seems to paradoxically decrease the likelihood of preeclampsia. We aimed to investigate the association between smoking and isolated proteinuria during pregnancy. In addition, we investigated the associations and potential interaction between smoking and proteinuria on the risk for preterm birth.

Methods

The study included all women with singleton pregnancies (N = 791,183) in Finland during the years 2006 to 2018, excluding those with previous kidney diseases, gestational hypertension or diabetes, or preeclampsia. Information on smoking and background factors were derived from the Finnish Medical Birth Register. Smoking was categorized as no smoking, quit in the first trimester, or continued smoking thereafter. Information on isolated proteinuria at any time of pregnancy was derived from the Finnish Hospital Discharge Register and the Finnish Medical Birth Register with an International Classification of Diseases (ICD) (Tenth Revision [ICD-10]) code O12, excluding gestational edema (O12.0). Logistic and linear regression models were used to estimate the associations.

Results

Of the participants, 14.6% were smokers, of which 36.9% quit smoking; 2534 (0.3%) had a diagnosis of isolated proteinuria. Those who quit smoking (odds ratio [OR] = 1.31, 95% confidence interval [CI] = 1.14-1.52) and those who continued smoking (OR = 1.29, 95% CI=1.15-1.46) were associated with having a diagnosis of isolated proteinuria. Isolated proteinuria (OR = 1.24, 95% CI = 1.03-1.49) and those who continued smoking (OR = 1.45, 95% CI = 1.40-1.50) were associated with preterm birth. The interaction of smoking and isolated proteinuria with preterm birth lacked statistical significance.

Conclusion

We found evidence of an association between smoking and the diagnosis of isolated proteinuria. Furthermore, smoking and a diagnosis of isolated proteinuria were both associated with a higher risk for preterm birth.

Tanshinone IIA Promoted Autophagy and Inhibited Inflammation to Alleviate Podocyte Injury in Diabetic Nephropathy

Purpose

Tanshinone IIA (Tan-IIA) is widely used in patients with diabetic nephropathy (DN), but its protective effect on podocytes in DN has not been well studied. In this study, the effects of Tan-IIA on autophagy and inflammation of glomerular podocytes in DN were observed in vivo and in vitro, and the underlying mechanisms were investigated. Irbesartan, an angiotensin II receptor blocker, is a representative medication for the clinical treatment of DN. So irbesartan was chosen as a positive control drug.

Methods

Eight-week-old male db/db mice were randomly divided into a DN group, an irbesartan group, and three groups receiving different doses of Tan-IIA. The control group consisted of the db/m littermate mice. Blood, urine, and kidney samples were taken from the mice after 12 weeks of continuous administration. Renal protection of Tan-IIA was evaluated using enzyme-linked immunosorbent assay kits, haematoxylin and eosin staining, transmission electron microscopy, Western blotting, and immunohistochemistry. In vitro, the protective effect of Tan-IIA on podocytes was explored using MPC5 cells cultured with high glucose.

Results

Tan-IIA significantly improved renal pathological injury and relieved the renal dysfunction in DN. Compared with the DN group, Tan-IIA could up-regulate the expression of Synaptopodin, Podocin, LC3II/I and Beclin-1 (p < 0.05), and down-regulate the expression of p62, F4/80, NF-κB p65, IL-1β, TNF-α and IL-6 (p < 0.05) both in vivo and in vitro, suggesting that Tan-IIA treatment alleviated podocyte injury by promoting autophagy and inhibiting inflammation during DN. The levels of p-PI3K/PI3K, p-Akt/Akt and p-mTOR/mTOR in Tan-IIA group were lower than those in DN group (p < 0.05), indicating that Tan-IIA inhibited the PI3K/Akt/mTOR signalling pathway in podocytes, which was a key pathway in regulating both autophagy and inflammation.

Conclusion

Tan-IIA prevented podocyte injury in DN by fostering autophagy and inhibiting inflammation, at least in part via inhibition of the PI3K/Akt/mTOR signalling pathway.

Effects of smokeless nicotine on blood physiology, biochemical, and histological alterations using Labeo rohita as a model organism

Objective

The present research was conducted to evaluate the negative effects of nicotine powder on the blood physiology, and biochemical and histological alterations of Labeo rohita.

Materials and Methods

Fish were divided into four groups (1-4). Fish groups 2, 3, and 4 were exposed to different concentrations of nicotine, such as 0.75, 1.25, and 1.75 mg/l, while group 1 acted as a control. To find out the long-term impact of nicotine on body physiology, we conducted a 42-day experiment. After the completion of the experiment, hematology, biochemical assays, and histology were done.

Results

Results revealed a considerable increase in HGB, red blood cells, WBCs, hematocrit, mean corpuscular volume, red cell distribution width -SD, procalcitonin, neutrophils, lymphocytes, monocytes, triglycerides, total cholesterol, low-density lipoprotein, very low-density lipoprotein, alanine transaminase, aspartate aminotransferase, globulin, thyroid stimulating hormone, BUN, creatinine, and blood glucose levels, whereas mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, RDW, platelet, high-density lipoprotein, albumin, total proteins, and T3 levels were significantly (p ≤ 0.05) decreased in exposed fish as compared to control group fish. Histological alterations showed that exposure to smokeless nicotine causes deleterious and degenerative effects in the liver, kidney, and gills of exposed fish.

Conclusion

Nicotine administration in fish results in adverse effects on different biochemical and hematological parameters and causes histological alterations in some vital organs of exposed fish.

Sex disparities in the association between serum cotinine and chronic kidney disease

INTRODUCTION

Despite the existence of numerous studies highlighting the adverse effects of smoking on kidney function, the investigation of the correlation between serum cotinine and chronic kidney disease (CKD) remains inconclusive due to insufficient evidence. Consequently, the primary objective of this study was to ascertain the association between serum cotinine levels and CKD.

METHODS

This study analyzed data from 10900 Americans participating in the National Health and Nutrition Examination Survey between 2005 and 2016. The independent variable under investigation was log serum cotinine, while the dependent variable was the presence of CKD. To investigate the potential linear and non-linear correlations between serum cotinine and CKD, logistic regression models and generalized additive models (GAM) were employed. Furthermore, stratified analyses and interaction tests were conducted to evaluate potential disparities in the relationship between serum cotinine and CKD, based on sex.

RESULTS

The median age in the study participants was 49.28 ± 17.96 years, and the median log serum cotinine (ng/mL) was -0.54 ± 1.68. The prevalence of CKD was found to be 17.04%. Multifactorial regression analysis did not show a statistically significant association between log serum cotinine and CKD (OR=1.02; 95% CI: 0.98-1.06, p=0.4387). A statistically significant non-linear association between log serum cotinine and CKD was also not observed in the GAM analysis (p non-linear value=0.091). Subgroup analyses revealed sex differences in the association between log serum cotinine and CKD. Briefly, males had a positive association between log serum cotinine and incident CKD (OR=1.08; 95% CI: 1.02-1.15, p=0.0049). In females, there was a U-shaped association between log serum cotinine and CKD, with an optimal inflection point for log serum cotinine of -0.30 (serum cotinine=0.5 ng/mL).

CONCLUSIONS

Cross-sectional analyses of NHANES data showed gender differences in the association between serum cotinine and the development of CKD.

Better Life's Essential 8 Is Associated With Lower Risk of Diabetic Kidney Disease: A Community-Based Study

Background Diabetic kidney disease (DKD) is a common diabetic complication and increases the complexity of diabetes management. No prospective study has focused on the association between DKD and Life's Essential 8 (LE8). Our study aims to examine the association between LE8 and DKD risk. Methods and Results A total of 7605 participants, aged 54.32±9.77 years, and 4688 participants, aged 56.11±10.38 years, were included in the longitudinal and trajectory analyses, respectively, from 2006 to 2020. The DKD was confirmed using data collected during each follow-up. LE8 was based on 4 health behaviors and 4 health factors. The range of each metric was 0 to 100, and the overall LE8 score was calculated as the unweighted average of all 8 component metric scores. The trajectories of LE8 during 2006 to 2010 were classified using latent mixture models. Cox models and restricted cubic splines were applied. After a median follow-up of 12.41 and 6.71 years in longitudinal and trajectory analyses, respectively, the DKD incidence decreased, with the LE8 level increasing (P-trend<0.05), and the linearity assumption for this relationship (P-nonlinear=0.685) had been satisfied. Adjusted hazard ratios (HRs) for the highest tertile were 0.77 (95% CI, 0.69-0.87) and 0.70 (95% CI, 0.62-0.78) in baseline and time-updated LE8 scores, respectively, compared with the lowest tertile. Adjusted HR was 0.53 (95% CI, 0.41-0.69) for the stable-high pattern compared with the stable-low pattern. Conclusions Although LE8 is an indicator of cardiovascular health, the beneficial impact of a high LE8 score is also evident in the protection of renal health among patients with diabetes.

Nicotine exacerbates diabetic nephropathy through upregulation of Grem1 expression

BACKGROUND

Diabetic nephropathy (DN) is a major complication of diabetes mellitus. Clinical reports indicate that smoking is a significant risk factor for chronic kidney disease, and the tobacco epidemic exacerbates kidney damage in patients with DN. However, the underlying molecular mechanisms remain unclear.

METHOD

In the present study, we used a diabetic mouse model to investigate the molecular mechanisms for nicotine-exacerbated DN. Twelve-week-old female mice were injected with streptozotocin (STZ) to establish a hyperglycemic diabetic model. After four months, the control and hyperglycemic diabetic mice were further divided into four groups (control, nicotine, diabetic mellitus, nicotine + diabetic mellitus) by intraperitoneal injection of nicotine or PBS. After two months, urine and blood were collected for kidney injury assay, and renal tissues were harvested for further molecular assays using RNA-seq analysis, real-time PCR, Western blot, and immunohistochemistry. In vitro studies, we used siRNA to suppress Grem1 expression in human podocytes. Then we treated them with nicotine and high glucose to compare podocyte injury.

RESULT

Nicotine administration alone did not cause apparent kidney injury, but it significantly increased hyperglycemia-induced albuminuria, BUN, plasma creatinine, and the kidney tissue mRNA expression of KIM-1 and NGAL. Results from RNA-seq analysis, real-time PCR, Western blot, and immunohistochemistry analysis revealed that, compared to hyperglycemia or nicotine alone, the combination of nicotine treatment and hyperglycemia significantly increased the expression of Grem1 and worsened DN. In vitro experiments, suppression of Grem1 expression attenuated nicotine-exacerbated podocyte injury.

CONCLUSION

Grem1 plays a vital role in nicotine-exacerbated DN. Grem1 may be a potential therapeutic target for chronic smokers with DN.

Protective Effect of Astragaloside IV against Cadmium-Induced Damage on Mouse Renal Podocytes (MPC5)

In this study, we investigated the protective effect of Astragaloside IV (Ast) on mouse podocytes and its possible mechanism of action by constructing a cadmium-induced mouse renal podocytes model. We investigated the effects of cadmium (Cd) toxicity on cell number, morphology, the mitochondrial status of subcellular organelles, protein and gene levels, and the protective effects of Ast by constructing a model of Cd-induced damage to mouse renal podocytes (MPC5) and giving Ast protection at the same time. The results showed that exposure of MPC5 cells to CdCl₂ culture medium containing 6.25 μM concentration acted with low cell mortality, but the mortality of MPC5 cells increased with the prolongation of cadmium exposure time. Given Ast, the death rate in the low dose group (12.5 μM) was significantly reduced, while the death rate in the medium dose group (25 μM) was extremely significantly reduced. In comparison to the control group, the Cd-exposed group exhibited a significant increase of 166.7% in malondialdehyde (MDA) content and a significant decrease of 17.1% in SOD activity. The mitochondrial membrane potential was also reduced to varying degrees. However, in the Ast-protected group compared to the Cd-exposed group, the MDA content significantly decreased by 20.8%, the SOD activity decreased by 7.14%, and the mitochondrial membrane potential showed a significant increase. Fluorescence staining of mitochondrial membrane potential indicated that Cd exposure caused mitochondrial apoptosis. In the 12-h cadmium-exposed group, the protein expression of Nephrin in mice significantly decreased by 33.4%. However, the expression of the Desmin protein significantly increased by 67.8%, and the expression of the autophagy protein LC3-II significantly increased by 55.5%. Meanwhile, the expression of PINK1, a mitochondrial autophagy pathway protein, was significantly increased in the 12 h and 24 h cadmium exposure groups. The mRNA level of PINK1 was significantly increased, and that of Parkin was decreased in the 48 h cadmium exposure group. Compared to the Cd-exposed group, the Ast group showed more significant improvements in the expression of podocyte structure, functional proteins, and mitochondrial autophagy pathway proteins. The immunological assay of mitochondrial autophagic pathway proteins further indicated that Cd-induced damage to MPC5 cells might be associated with the dysregulation of mitochondrial autophagy.

Tobacco exposure in adults and children with proteinuric glomerulopathies: a NEPTUNE cohort study

BACKGROUND

Tobacco exposure has been recognized as a risk factor for cardiovascular disease (CVD) and progression of kidney disease. Patients with proteinuric glomerulopathies are at increased risk for cardiovascular morbidity and mortality. Multiple studies have linked tobacco exposure to CVD and chronic kidney disease, but the relationships between smoking and proteinuric glomerulopathies in adults and children have not been previously explored.

METHODS

Data from the Nephrotic Syndrome Study Network (NEPTUNE), a multi-center prospective observational study of participants with proteinuric glomerulopathies, was analyzed. 371 adults and 192 children enrolled in NEPTUNE were included in the analysis. Self-reported tobacco exposure was classified as non-smoker, active smoker, former smoker, or exclusive passive smoker. Baseline serum cotinine levels were measured in a sub-cohort of 178 participants.

RESULTS

The prevalence of active smokers, former smokers and exclusive passive smoking among adults at baseline was 14.6%, 29.1% and 4.9%, respectively. Passive smoke exposure was 16.7% among children. Active smoking (reference non-smoking) was significantly associated with greater total cholesterol among adults (β 17.91 95% CI 0.06, 35.76, p = 0.049) while passive smoking (reference non-smoking) was significantly associated with greater proteinuria over time among children (β 1.23 95% CI 0.13, 2.33, p = 0.03). Higher cotinine levels were associated with higher baseline eGFR (r = 0.17, p = 0.03).

CONCLUSION

Tobacco exposure is associated with greater risk for CVD and worse kidney disease outcomes in adults and children with proteinuric glomerulopathies. Preventive strategies to reduce tobacco exposure may help protect against future cardiovascular and kidney morbidity and mortality in patients with proteinuric glomerulopathies.

B7-1 mediates podocyte injury and glomerulosclerosis through communication with Hsp90ab1-LRP5-β-catenin pathway

Podocyte injury is a hallmark of glomerular diseases; however, the underlying mechanisms remain unclear. B7-1 is increased in injured podocytes, but its intrinsic role is controversial. The clinical data here revealed the intimate correlation of urinary B7-1 with severity of glomerular injury. Through transcriptomic and biological assays in B7-1 transgenic and adriamycin nephropathy models, we identified B7-1 is a key mediator in podocyte injury and glomerulosclerosis through a series of signal transmission to β-catenin. Using LC-MS/MS, Hsp90ab1, a conserved molecular chaperone, was distinguished to be an anchor for transmitting signals from B7-1 to β-catenin. Molecular docking and subsequent mutant analysis further identified the residue K69 in the N terminal domain of Hsp90ab1 was the key binding site for B7-1 to activate LRP5/β-catenin pathway. The interaction and biological functions of B7-1-Hsp90ab1-LRP5 complex were further demonstrated in vitro and in vivo. We also found B7-1 is a novel downstream target of β-catenin. Our results indicate an intercrossed network of B7-1, which collectively induces podocyte injury and glomerulosclerosis. Our study provides an important clue to improve the therapeutic strategies to target B7-1.

Xenobiotics Delivered by Electronic Nicotine Delivery Systems: Potential Cellular and Molecular Mechanisms on the Pathogenesis of Chronic Kidney Disease

Chronic kidney disease (CKD) is characterized as sustained damage to the renal parenchyma, leading to impaired renal functions and gradually progressing to end-stage renal disease (ESRD). Diabetes mellitus (DM) and arterial hypertension (AH) are underlying diseases of CKD. Genetic background, lifestyle, and xenobiotic exposures can favor CKD onset and trigger its underlying diseases. Cigarette smoking (CS) is a known modified risk factor for CKD. Compounds from tobacco combustion act through multi-mediated mechanisms that impair renal function. Electronic nicotine delivery systems (ENDS) consumption, such as e-cigarettes and heated tobacco devices, is growing worldwide. ENDS release mainly nicotine, humectants, and flavorings, which generate several byproducts when heated, including volatile organic compounds and ultrafine particles. The toxicity assessment of these products is emerging in human and experimental studies, but data are yet incipient to achieve truthful conclusions about their safety. To build up the knowledge about the effect of currently employed ENDS on the pathogenesis of CKD, cellular and molecular mechanisms of ENDS xenobiotic on DM, AH, and kidney functions were reviewed. Unraveling the toxic mechanisms of action and endpoints of ENDS exposures will contribute to the risk assessment and implementation of proper health and regulatory interventions.

ACEI and ARB Lower the Incidence of End-Stage Renal Disease among Patients with Diabetic Nephropathy: A Meta-analysis

Objective

This study explores the effects of Angiotensin-Converting Enzyme Inhibitors (ACEI) or Angiotensin Receptor Blockers (ARB) on the incidence of end-stage renal disease (ESRD) in diabetic nephropathy (DN) patients.

Methods

Literatures were searched in PubMed, Embase, Medline, CENTRAL, and CNKI databases. These literatures included a randomized controlled trial to evaluate the efficacy of ACEI and ARB among patients with DN. The endpoint event included the occurrence of ERSD. Risk ratio (RR) and 95% confidence interval (CI) were used to represent the combined effect size. A fixed-effect model was used to analyze if heterogeneity did not exist between literatures. If heterogeneity exists between literatures, a random-effect model was used to analyze. The source of heterogeneity was explored by subgroup analysis and sensitivity analysis.

Results

A total of 11 literatures were included in the study. The RR of ESRD was 0.79 (95% CI (0.79, 0.90), Z = 3.58, P = 0.0003) in the patients treated with RAS blockers compared with placebo, and there was no heterogeneity between studies (Chi² = 5.09, P = 0.88, I² = 0%). The funnel plot showed that the scatter point was biased to the left with publication bias. The RR of ESRD was 0.63 (95% CI (0.41, 0.95), Z = 2.18, P = 0.03) in the patients treated with ACEI compared with placebo. There was no heterogeneity between studies (Chi² = 2.23, P = 0.95, I² = 0%). Compared with placebo, RR of ESRD among patients with ARB intervention was 0.81 (95% CI (0.71, 0.93), Z = 3.00, P = 0.003). There was no heterogeneity between studies (Chi² = 1.49, P = 0.48, I² = 0%).

Conclusion

ACEI and ARB can reduce the risk of ESRD among diabetic nephropathy patients.

Diabetes duration and types of diabetes treatment in data-driven clusters of patients with diabetes

BACKGROUND

This study aimed to cluster patients with diabetes and explore the association between duration of diabetes and diabetes treatment choices in each cluster.

METHODS

A Two-Step cluster analysis was performed on 1332 Chinese patients with diabetes based on six parameters (glutamate decarboxylase antibodies, age at disease onset, body mass index, glycosylated hemoglobin, homeostatic model assessment 2 to estimate β-cell function and insulin resistance). Associations between the duration of diabetes and diabetes treatment choices in each cluster of patients were analyzed using Kaplan-Meier survival curves and logistic regression models.

RESULTS

The following five replicable clusters were identified: severe autoimmune diabetes (SAID), severe insulin-deficient diabetes (SIDD), severe insulin-resistant diabetes (SIRD), mild obesity-related diabetes (MOD), and mild age-related diabetes (MARD). There were significant differences in blood pressure, blood lipids, and diabetes-related complications among the clusters (all P < 0.05). Early in the course of disease (≤5 years), compared with the other subgroups, the SIRD, MOD, and MARD populations were more likely to receive non-insulin hypoglycemic agents for glycemic control. Among the non-insulin hypoglycemic drug options, SIRD had higher rates of receiving metformin, alpha-glucosidase inhibitor (AGI), and glucagon-like peptide-1 drug; the MOD and MARD groups both received metformin, AGI and sodium-glucose cotransporter 2 inhibitor (SGLT-2i) drug ratio was higher. While the SAID and SIDD groups were more inclined to receive insulin therapy than the other subgroups, with SAID being more pronounced. With prolonged disease course (>5 years), only the MOD group was able to accept non-insulin hypoglycemic drugs to control the blood sugar levels, and most of them are still treated with metformin, AGI, and SGLT-2i drugs. While the other four groups required insulin therapy, with SIDD being the most pronounced.

CONCLUSIONS

Clustering of patients with diabetes with a data-driven approach yields consistent results. Each diabetes cluster has significantly different disease characteristics and risk of diabetes complications. With the development of the disease course, each cluster receives different hypoglycemic treatments.

Urinary exosomal circular RNAs of sex chromosome origin are associated with gender-related risk differences of clinicopathological features in patients with IgA nephropathy

BACKGROUND

There are arguments for individualized treatments and the necessity of non-invasive biomarkers for patients with IgA nephropathy (IgAN) according to gender, but the rationale remains unclear. We aimed to investigate the relationship between urine exosomal circular RNA (circRNA) levels, related genes, clinical features, and renal pathological features in IgA nephropathy patients of different genders.

METHODS

Clinicopathological data from patients of different genders from a multicenter cohort were retrospectively analyzed. We used the Oxford classification to examine the severity of pathological damage in these patients. We compared clinical features and renal pathologies between IgAN patients of different genders. Using findings of urine exosomal circRNAs from male IgAN patients, we analyzed the relationship between this factor, the regulated genes located on the sex chromosomes, and renal pathologies.

RESULTS

A total of 502 IgAN patients were included. The proportion of male patients with crescent formation was higher than that of females (p = 0.019). Multivariate logistic regression analysis showed that proteinuria was an independent marker for crescent formation in male and female patients with IgAN, while smoking and higher low-density lipoprotein cholesterol (LDL-C) levels were independent risk factors for crescent formation in males alone. Urine exosomal circRNA chrY:15478147-15481229- located on the Y chromosome in male patients was negatively correlated with the expressions of UTY in specific regions of the Y chromosome.

CONCLUSION

Compared with female patients, males with IgAN had more severe renal dysfunction and a higher probability of glomerular crescent formation. Urine exosomal circRNA chrY:15478147-15481229- might participate in the pathogenesis of IgAN in male patients by altering UTY expressions.

Podocyte Lipotoxicity in CKD

CKD represents the ninth most common cause of death in the United States but, despite this large health burden, treatment options for affected patients remain limited. To remedy this, several relevant pathways have been identified that may lead to novel therapeutic options. Among them, altered renal lipid metabolism, first described in 1982, has been recognized as a common pathway in clinical and experimental CKD of both metabolic and nonmetabolic origin. This observation has led many researchers to investigate the cause of this renal parenchyma lipid accumulation and its downstream effect on renal structure and function. Among key cellular components of the kidney parenchyma, podocytes are terminally differentiated cells that cannot be easily replaced when lost. Clinical and experimental evidence supports a role of reduced podocyte number in the progression of CKD. Given the importance of the podocytes in the maintenance of the glomerular filtration barrier and the accumulation of TG and cholesterol-rich lipid droplets in the podocyte and glomerulus in kidney diseases that cause CKD, understanding the upstream cause and downstream consequences of lipid accumulation in podocytes may lead to novel therapeutic opportunities. In this review, we hope to consolidate our understanding of the causes and consequences of dysregulated renal lipid metabolism in CKD development and progression, with a major focus on podocytes.