Glomerular hyperfiltration: definitions, mechanisms and clinical implications

Predictive effect of estimated glomerular filtrate rate by creatinine or cystatin C on mortality in patients with coronary artery disease

BACKGROUND

Renal dysfunction leads to poor prognosis of patients with coronary artery disease (CAD). Current studies have reported the prognosis or mortality of various diseases using different estimated glomerular filtrate rate (eGFR) formulas, while the performance of these equations is unclear in CAD patients. We aim to evaluate the predict effect of creatinine-based eGFR (eGFRcr), cystatin C-based eGFR (eGFRcys), and both creatinine and cystatin C-based eGFR (eGFRcr-cys) in CAD patients.

METHODS

A total of 23,178 patients with CAD were included from CIN-II cohort study. The association of eGFRcr, eGFRcys and eGFRcr-cys with cardiovascular and all-cause mortality was detected by Cox regression analysis. The predictive effect of eGFRcr, eGFRcys and eGFRcr-cys on mortality was assessed.

RESULTS

During a median follow up of 4.3 years, totally 2051 patients (8.8%) experience all-cause mortality, of which 1427 patients (6.2%) died of cardiovascular disease. For the detection of cardiovascular mortality among CAD patients, eGFRcr-cys had high discriminatory capacity with area under the curve (AUC) in receiver operator characteristic analysis of 0.730, which was significantly better than eGFRcr (AUC = 0.707, p < 0.001) and eGFRcys (AUC = 0.719, p < 0.001). Similar results were observed in all-cause mortality. Restricted cubic spline showed a U-shaped association between eGFRcr and all outcomes in patients with both reduced and supranormal eGFR levels, while a L-shaped association in eGFRcys and eGFRcr-cys.

CONCLUSIONS

Estimated GFR based on both creatinine and cystatin C has highest predictive effect for cardiovascular and all-cause mortality among CAD patients. Meanwhile, supranormal eGFRcr may indicate a higher risk of mortality.

The key mediator of diabetic kidney disease: Potassium channel dysfunction

Diabetic kidney disease is a leading cause of end-stage renal disease, making it a global public health concern. The molecular mechanisms underlying diabetic kidney disease have not been elucidated due to its complex pathogenesis. Thus, exploring these mechanisms from new perspectives is the current focus of research concerning diabetic kidney disease. Ion channels are important proteins that maintain the physiological functions of cells and organs. Among ion channels, potassium channels stand out, because they are the most common and important channels on eukaryotic cell surfaces and function as the basis for cell excitability. Certain potassium channel abnormalities have been found to be closely related to diabetic kidney disease progression and genetic susceptibility, such as KATP, KCa, Kir, and KV. In this review, we summarized the roles of different types of potassium channels in the occurrence and development of diabetic kidney disease to discuss whether the development of DKD is due to potassium channel dysfunction and present new ideas for the treatment of DKD.

The extent of kidney involvement in paediatric tuberous sclerosis complex

BACKGROUND

Tuberous sclerosis (TSC)-associated kidney disease is a leading cause of mortality in adults with TSC. This study aimed to understand TSC features in children, particularly kidney involvement, to inform clinical care for this specific group.

METHODS

This retrospective cohort study included all paediatric (< 19 years) TSC cases at a large tertiary paediatric nephrology centre. Relevant data were collected from patients' records, statistical analyses were performed to identify associations between variables, survival probabilities were estimated with Kaplan‒Meier curves, and log-rank tests were conducted to assess survival differences among genetic mutations.

RESULTS

A total of 182 children with TSC were included. Among the 145 children with available kidney imaging data, 78.6% (114/145) exhibited kidney lesions. Angiomyolipomas (AMLs) were significantly more prevalent in the TSC2 mutation group (p = 0.018). Children with TSC2 mutations generally had poorer lesion-free survival than those with TSC1 mutations, but this difference was only significant for AMLs (p = 0.030). The change in size of largest AMLs increased with age and doubled in children above 9 years; a similar pattern was observed when stratified by genetic mutation. In contrast, kidney cysts exhibited two peaks: one in children under 5 years (2.31 mm/year) and the second in children between 15-19 years (2.82 mm/year). Chronic kidney disease was observed in 12.3% (10/81) of children, and high-risk AMLs above 3 cm were observed in 9% (13/145).

CONCLUSIONS

While TSC kidney disease emerges later in the disease course than neurological features, our findings emphasise the importance of kidney surveillance during childhood, including routine kidney imaging, kidney function, and blood pressure monitoring.

Effects of Empagliflozin in Type 2 Diabetes With and Without Chronic Kidney Disease and Nondiabetic Chronic Kidney Disease: Protocol for 3 Crossover Randomized Controlled Trials (SiRENA Project)

BACKGROUND

Sodium-glucose-cotransporter 2 inhibitors (SGLT2is) have revolutionized the treatment of type 2 diabetes mellitus (DM2) and chronic kidney disease (CKD), reducing the risk of cardiovascular and renal end points by up to 40%. The underlying mechanisms are not fully understood.

OBJECTIVE

The study aims to examine the effects of empagliflozin versus placebo on renal hemodynamics, sodium balance, vascular function, and markers of the innate immune system in patients with DM2, DM2 and CKD, and nondiabetic CKD.

METHODS

We conducted 3 double-blind, crossover, randomized controlled trials, each with identical study protocols but different study populations. We included patients with DM2 and preserved kidney function (estimated glomerular filtration rate >60 mL/min/1.73 m2), DM2 and CKD, and nondiabetic CKD (both with estimated glomerular filtration rate 20-60 mL/min/1.73 m2). Each participant was randomly assigned to 4 weeks of treatment with either 10 mg of empagliflozin once daily or a matching placebo. After a wash-out period of at least 2 weeks, participants were crossed over to the opposite treatment. End points were measured at the end of each treatment period. The primary end point was renal blood flow measured with 82Rubidium positron emission tomography-computed tomography (82Rb-PET/CT). Secondary end points include glomerular filtration rate measured with 99mTechnetium-diethylene-triamine-pentaacetate (99mTc-DTPA) clearance, vascular function assessed by forearm venous occlusion strain gauge plethysmography, measurements of the nitric oxide (NO) system, water and sodium excretion, body composition measurements, and markers of the complement immune system.

RESULTS

Recruitment began in April 2021 and was completed in September 2022. Examinations were completed by December 2022. In total, 49 participants completed the project: 16 participants in the DM2 and preserved kidney function study, 17 participants in the DM2 and CKD study, and 16 participants in the nondiabetic CKD study. Data analysis is ongoing. Results are yet to be published.

CONCLUSIONS

This paper describes the rationale, design, and methods used in a project consisting of 3 double-blind, crossover, randomized controlled trials examining the effects of empagliflozin versus placebo in patients with DM2 with and without CKD and patients with nondiabetic CKD, respectively.

TRIAL REGISTRATION

EU Clinical Trials Register 2019-004303-12; https://www.clinicaltrialsregister.eu/ctr-search/search?query=2019-004303-12, EU Clinical Trials Register 2019-004447-80; https://www.clinicaltrialsregister.eu/ctr-search/search?query=2019-004447-80, EU Clinical Trials Register 2019-004467-50; https://www.clinicaltrialsregister.eu/ctr-search/search?query=and+2019-004467-50.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/56067.

Correlation between the triglyceride-glucose index and chronic kidney disease among adults with metabolic-associated fatty liver disease: fourteen-year follow-up

Background and aims

According to previous studies, triglyceride-glucose (TyG) is related to chronic kidney disease (CKD), but no studies have explored the correlation between TyG and CKD among adults with metabolic dysfunction-associated fatty liver disease (MAFLD). We aimed to explore the associations of the TyG index with CKD among adults with MAFLD.

Methods

In this retrospective observational cohort study, data from 11,860 participants who underwent a minimum of three health assessments between 2008 and 2015 were retrospectively collected. Participants were followed up until the final medical visit or health examination. CKD refers to an eGFR < 60 mL/min per 1·73 m2 or the occurrence of two or more incidents of proteinuria.

Results

Within a median 10·02-year follow-up period, 2005 (16·9%) participants reported developing CKD. Multivariate Cox regression models indicated a noticeable correlation between the TyG index and CKD incidence (HR per unit increase, 1.19; 95% CI: 1.09-1.29) and between the TyG index and CKD incidence (HR per SD increase, 1.12; 95% CI: 1.06-1.18). The CKD incidence increased by 1.8 times in participants in the highest TyG index quartile relative to patients in the lowest quartile of the TyG index quartile (HR 1·18, 95% CI: 1.01-1.38, P = 0.007). According to subgroup analysis, an elevated TyG index is likely to become more harmful to participants younger than 60 years (P for interaction = 0.035).

Conclusion

An elevated TyG index may increase CKD incidence among MAFLD adults, particularly among younger people. Early intervention may help reduce the incidence of CKD.

SGLT2 inhibitors in diabetic and non-diabetic kidney transplant recipients: current knowledge and expectations

The beneficial effect of sodium-glucose cotransporter-2 inhibitors (SGLT2i) have been shown recently in numerous randomized controlled trials (RCT) and systematic reviews. According to KDIGO guidelines, SGLT2i currently represent a first choice for diabetic patients with chronic kidney disease (CKD). In addition, a recent meta-analysis of 13 large led by the 'SGLT2 inhibitor Meta-Analysis Cardio-Renal Trialists' Consortium' (SMART-C) provided solid evidence of SGLT2i beneficial effects in CKD or in patients with heart failure, with and without diabetes. Collectively, the patients treated with SGLT2i had a decreased risk of CKD progression, acute kidney injury (AKI), end-stage kidney disease (ESKD) or death from heart failure. Whether these cardio-renal benefits should be extrapolated to kidney transplant recipients (KTR) needs to be assessed in further studies. In this article, we report recent data accumulated so far in the literature, looking at the efficacy and safety of SGLT2i in diabetic and non-diabetic KTR. We found encouraging data regarding the use of SGLT2i in KTR with diabetes. These agents appeared to be safe, and they reduced body weight and blood pressure in this group of patients. Potential effects on kidney graft function and survival are yet to be investigated.

Pre-transplant glomerular hyperfiltration is not a risk factor for increased renal morbidity and mortality in pediatric stem cell transplant patients

Low glomerular filtration rate (GFR) prior to stem cell transplant (SCT) is associated with increased morbidity and mortality. The implications of abnormally high GFRs, or glomerular hyperfiltration, prior to SCT are unknown. Twenty-two of 74 consecutive pediatric SCT patients over 2 years old at a single center were hyperfiltrating prior to SCT, median nuclear medicine GFR 154 mL/min/1.73 m2 [interquartile range: 146-170]. There was no association between hyperfiltration and any transplant demographics, nor between hyperfiltration and acute kidney injury (p = .8), renal replacement therapy (p = .63), 1-year event-free survival (p = 1), or abnormal creatinine-based estimated GFR at a median follow-up of 4.7 years (p = .73).

Central Body Fat Distribution and Kidney Function after Living Kidney Donation

BACKGROUND

In most screening guidelines, high body mass index (BMI) is considered a contraindication for kidney donation. New insights suggest that central body fat distribution might provide greater power in assessing kidney risk. This study aimed to determine whether BMI and central body fat distribution measures are associated with long-term kidney function after donor nephrectomy. We hypothesized that higher BMI, waist circumference (WC), and waist-to-height ratio (WHtR) were associated with lower kidney function long term after donation.

METHODS

The study population consisted of living kidney donors. BMI, WC, and WHtR were measured during donor screening. The outcome postdonation kidney function was assessed using measured GFR (mGFR) (mGFR, 125 I-iothalamate infusion) at 3 months ( n =1042), 5 years ( n =556), and 10 years ( n =210) of follow-up. Primary multivariable linear regression analyses were performed with BMI and WC and secondary analyses with WHtR. Linear mixed models were performed to investigate change in postdonation eGFR.

RESULTS

The donor age was 52±11 years, and 48% were male. The mean BMI was 26.1±3.6 kg/m 2 , and WC was 91±11 cm. Higher predonation BMI was associated with lower mGFR throughout follow-up: -1.35 (95% confidence interval [CI], -1.95 to -0.80), -1.55 (95% CI, -2.50 to -0.65), and -2.35 (95% CI, -4.10 to -0.60) ml/min per m 2 per 5 kg/m 2 higher BMI at 3 months, 5, and 10 years after donation, respectively, adjusted for sex, age, and predonation GFR. For WC, differences in mGFR were -1.30 (95% CI, -1.70 to -0.90), -1.50 (95% CI, -2.20 to -0.80), and -1.70 (95% CI, -3.00 to -0.50) ml/min per m 2 per 10 cm higher WC at 3 months, 5, and 10 years after donation, respectively. In male donors, BMI and WC were significantly associated with a negative postdonation change in eGFR.

CONCLUSIONS

Higher BMI and WC were independently associated with lower GFR (long term) after living kidney donation.

Pediatric kidney dimensions and risk of persistent albuminuria in Mexican adolescents

In Mexico, chronic kidney disease of unknown origin is highly prevalent. Screening studies in adolescents have shown persistent microalbuminuria (pACR), adaptive podocytopathy and decreased kidney volume (KV). Here, we sought to develop normality tables of kidney dimensions by ultrasound in the Mexican state of Aguascalientes pediatric population (0 to 18y) and evaluate the relationship between the KV and pACR among the region's adolescents in a cross-sectional study. Kidney length (KL) and KV were determined by ultrasound. Our findings were compared with those in international literature of different populations where tables and graphs of normal kidney dimensions by ultrasound were reported. We compared organ dimensions in individuals above the age of 11 without albuminuria with those in patients with pACR recruited through screening studies in adolescents in Aguascalientes. This included 1068 individuals to construct percentile tables and graphs of the KL. Kidney dimensions were significantly lower when compared with all international comparisons. From a total 14,805 screen individuals, we compared 218 adolescents with pACR and 377 individuals without significant albuminuria. The Total KV adjusted to body surface (TKVBS) was significantly associated with pACR (odds ratio 1.03, 95% confidence interval 1.02-1.03). The upper quartile of TKVBS was highly associated with pACR (7.57, 4.13-13.87), hypertension (2.53, 1.66-3.86), and hyperfiltration (26 vs 11.5%). Thus, TKVBS is directly associated with pACR while greater KV, arterial hypertension, and hyperfiltration in patients with pACR suggest that the increase in volume is secondary to kidney hypertrophy. Additionally, the adaptative podocytopathy with low fibrosis seen on kidney biopsy which was performed in a subset of patients, and the smaller kidney dimensions in our population point to prenatal oligonephronia as the primary cause of the detected kidney disease.

The Relationship of Alcohol Consumption and Drinking Pattern to the Risk of Glomerular Hyperfiltration in Middle-aged Japanese Men: The Kansai Healthcare Study

BACKGROUND

Glomerular hyperfiltration has been reported to be associated with adverse renal outcomes in the general population. It is not known whether drinking pattern is associated with the risk of glomerular hyperfiltration in healthy individuals.

METHODS

We prospectively followed middle-aged 8,640 Japanese men with normal renal function, no proteinuria, no diabetes, and no use of antihypertensive medications at entry. Data on alcohol consumption were gathered by questionnaire. Glomerular hyperfiltration was defined as estimated glomerular filtration rate (eGFR) ≥117 mL/min/1.73 m2, which was the upper 2.5th percentile value of eGFR in the entire cohort.

RESULTS

During 46,186 person-years of follow-up, 330 men developed glomerular hyperfiltration. In a multivariate model, for men who consumed alcohol on 1-3 days per week, alcohol consumption of ≥69.1 g ethanol/drinking day was significantly associated with the risk of glomerular hyperfiltration (hazard ratio [HR] 2.37; 95% confidence interval [CI], 1.18-4.74) compared with non-drinkers. For those who consumed alcohol on 4-7 days per week, higher alcohol consumption per drinking day was associated with a higher risk of glomerular hyperfiltration: the HRs for alcohol consumption of 46.1-69.0, and ≥69.1 g ethanol/drinking day were 1.55 (95% CI, 1.01-2.38), and 1.78 (95% CI, 1.02-3.12), respectively.

CONCLUSION

For high drinking frequency per week, more alcohol intake per drinking day was associated with an increased risk of glomerular hyperfiltration, while for low drinking frequency per week, only very high alcohol intake per drinking day was associated with an increased risk of glomerular hyperfiltration in middle-aged Japanese men.

Association Between Plant-based Diet and Kidney Function in Adults

OBJECTIVE

A plant-based diet has both antioxidant and anti-inflammatory properties. Therefore, it is hypothesized that adherence to a plant-based diet may have a positive effect on kidney function. The study aimed to determine the association between the plant-based diet index (PDI) and chronic kidney disease (CKD).

METHODS

This cross-sectional analysis used information from the Ravansar noncommunicable diseases cohort study, which included 9,746 participants between the ages of 35 and 65. By measuring the estimation glomerular filtration rate (eGFR) with the modification of diet in the renal disease equation, CKD was determined. Using a food frequency questionnaire, the PDI was computed based on food intake. To determine odds ratios (ORs), multivariable logistic regression models were utilized.

RESULTS

1,058 (10.86%) participants had CKD (eGFR<60 mL/min/1.73 m2), and the mean PDI was 54.22 ± 6.68. The mean eGFR in the group with a high PDI score was significantly higher than the group with a low PDI score (fourth quartile: 79.20 ± 0.36 vs. first quartile: 72.95 ± 0.31, P < .001). Adherence to a plant-based diet was more prevalent in those with a higher socioeconomic status (P < .001). After adjusting for potential confounders, the odds of CKD in the third and fourth quartiles of PDI were 25% (OR: 0.75; 95% confidence interval: 0.62-0.91) and 39% (OR: 0.61; 95% confidence interval: 0.48-0.78, P trend<.001) lower than the first quartile, respectively.

CONCLUSIONS

The findings of this study suggest that having a plant-based diet may prevent the prevalent CDK. However, further studies with a cohort design are recommended.

Risk of mortality and cause of death according to kidney function parameters: a nationwide observational study in Korea

BACKGROUND

Further study is warranted to determine the association between estimated glomerular filtration rate (eGFR) or albuminuria and the risk of death from diverse causes.

METHODS

We screened >10 million general health screening examinees who received health examinations conducted in 2009 using the claims database of Korea. After the exclusion of those previously diagnosed with renal failure and those with missing data, 9,917,838 individuals with available baseline kidney function measurements were included. The primary outcome was mortality and cause-specific death between 2009 and 2019 identified through death certificates based on the diagnostic codes of International Classification of Diseases, 10th revision. Multivariable Cox regression analysis adjusted for various clinicodemographic and social characteristics was used to assess mortality risk.

RESULTS

The hazard ratio of death was significantly high in both the eGFR <60 mL/min/1.73 m2 and in the eGFR ≥120 mL/ min/1.73 m2 groups in univariable and multivariable regression analyses when compared to those within the reference range (eGFR of 90-120 mL/min/1.73 m2). The results were similar for death by cardiovascular, cancer, infection, endocrine, respiratory, and digestive causes. We also found that albuminuria was associated with higher risk of death regardless of eGFR range, and those in the higher categories of dipstick albuminuria showed higher risk.

CONCLUSION

We reconfirmed the significant association between eGFR, albuminuria, and mortality. Healthcare providers should keep in mind that albuminuria and decreased eGFR as well as kidney hyperfiltration are independent predictors of mortality.

Renal Congestion in Heart Failure: Insights in Novel Diagnostic Modalities

Heart failure is increasingly prevalent and is estimated to increase its burden in the following years. A well-reported comorbidity of heart failure is renal dysfunction, where predominantly changes in the patient's volume status, tubular necrosis or other mechanical and neurohormonal mechanisms seem to drive this impairment. Currently, there are established biomarkers evaluating the patient's clinical status solely regarding the cardiovascular or renal system. However, as the coexistence of heart and renal failure is common and related to increased mortality and hospitalization for heart failure, it is of major importance to establish novel diagnostic techniques, which could identify patients with or at risk for cardiorenal syndrome and assist in selecting the appropriate management for these patients. Such techniques include biomarkers and imaging. In regards to biomarkers, several peptides and miRNAs indicative of renal or tubular dysfunction seem to properly identify patients with cardiorenal syndrome early on in the course of the disease, while changes in their serum levels can also be helpful in identifying response to diuretic treatment. Current and novel imaging techniques can also identify heart failure patients with early renal insufficiency and assess the volume status and the effect of treatment of each patient. Furthermore, by assessing the renal morphology, these techniques could also help identify those at risk of kidney impairment. This review aims to present all relevant clinical and trial data available in order to provide an up-to-date summary of the modalities available to properly assess cardiorenal syndrome.

Coffee consumption and risk of kidney function decline in a Dutch population-based cohort

BACKGROUND AND AIMS

Whether coffee consumption is associated with changes in estimated glomerular filtration rate (eGFR) is unknown. We investigated the relationship between coffee consumption and annual eGFR change in a large Dutch population-based study.

METHODS AND RESULTS

This study was performed in 78,346 participants without chronic kidney disease (CKD) in the population-based Lifelines Cohort Study. Coffee consumption was assessed at baseline using food frequency questionnaires. Outcomes were annual eGFR change and a composite kidney outcome (defined as eGFR <60 mL/min per 1.73 m2 or >20 % eGFR decline). Multivariable linear and logistic regression analyses were used to evaluate the associations of coffee consumption (categories and cups/day) with kidney outcomes. Overall, 90 % of the participants drank coffee daily and 36 % drank >2-4 cups/day. Unadjusted mean ± SD annual eGFR change ranged from -2.86 ± 2.96 (for non-coffee drinkers) to -2.35 ± 2.62 (for participants consuming >6 cups/day) mL/min per 1.73 m2. During 3.6 ± 0.9 years follow-up, 11.1 % of participants reached the composite kidney outcome. As compared to non-coffee drinkers, higher coffee consumption was associated with less annual eGFR decline in multivariable models (β [95 % CIs] ranged from 0.15 [0.07, 0.22] for >0-2 cups/day to 0.29 [0.20, 0.38] for >6 cups/day, P-trend <0.001). Consumption of one more cup of coffee per day was associated with a 3 % lower risk of the composite kidney outcome (OR [95%CI], 0.97 [0.96, 0.99]). The inverse association was more pronounced in a subgroup of individuals with diabetes.

CONCLUSION

Coffee consumption was inversely associated with annual eGFR change and CKD risk in a large Dutch population-based cohort.

Light and Shadow of Na-Glucose Cotransporter 2 Inhibitors in the Treatment of Diabetes Mellitus: Points for Improvement Based on Our Clinical Experience

We analyzed the effect of Na-glucose cotransporter 2 inhibitors (SGLT2-I) in diabetic patients visiting our hospital. The study included 236 patients treated with SGLT2-I alone or with codiabetic drugs for at least two years. We analyzed overtime changes in glycosylated hemoglobin A1c (HbA1c) in the patients by repeated analyses of variance (ANOVA) and evaluated the therapeutic effect. HbA1c levels decreased significantly in the first six months after treatment. Afterward, they leveled off and increased slightly over the next two years. Six months after treatment, the mean (SD) of HbA1c was 8.19 (1.46) %; the mean difference dropped by 0.91%, and HbA1c in mild DM2 did not drop by below 8.0%. Overall, there was only a slight improvement. We performed multivariate logistic regression analysis using a model with or without improvement as the objective variable and several explanatory variables. Na and Hct were significant factors. They increased considerably over six months and then leveled off. eGFR significantly reduced in the hyperfiltration group six months after treatment. The annual decline rate in eGFR was also faster, even in the nonhyperfiltration group than in the healthy subjects, which may be a characteristic of renal clearance in SGLT2-I treatment. In conclusion, SGLT2-I is an excellent antidiabetic, nephroprotective agent to eliminate hyperfiltration, but unfortunately, SGLT2-I alone does not have enough power to reduce blood glucose levels. SGLT2-I, with insulin or insulin secretagogues, enhances insulin resistance, induces hyperinsulinemia, and exacerbates type 2 DM. In contrast, SGLT2-I, with noninsulin antidiabetic agents and a low-carbohydrate diet, may bring better results.

Application of nanotechnology in the treatment of glomerulonephritis: current status and future perspectives

Glomerulonephritis (GN) is the most common cause of end-stage renal failure worldwide; in most cases, it cannot be cured and can only delay the progression of the disease. At present, the main treatment methods include symptomatic therapy, immunosuppressive therapy, and renal replacement therapy. However, effective treatment of GN is hindered by issues such as steroid resistance, serious side effects, low bioavailability, and lack of precise targeting. With the widespread application of nanoparticles in medical treatment, novel methods have emerged for the treatment of kidney diseases. Targeted transportation of drugs, nucleic acids, and other substances to kidney tissues and even kidney cells through nanodrug delivery systems can reduce the systemic effects and adverse reactions of drugs and improve treatment effectiveness. The high specificity of nanoparticles enables them to bind to ion channels and block or enhance channel gating, thus improving inflammation. This review briefly introduces the characteristics of GN, describes the treatment status of GN, systematically summarizes the research achievements of nanoparticles in the treatment of primary GN, diabetic nephropathy and lupus nephritis, analyzes recent therapeutic developments, and outlines promising research directions, such as gas signaling molecule nanodrug delivery systems and ultrasmall nanoparticles. The current application of nanoparticles in GN is summarized to provide a reference for better treatment of GN in the future.

Narrative review investigating the nephroprotective mechanisms of sodium glucose cotransporter type 2 inhibitors in diabetic and nondiabetic patients with chronic kidney disease

Background and aims

Outcome trials using sodium glucose cotransporter type 2 inhibitors have consistently shown their potential to preserve kidney function in diabetic and nondiabetic patients. Several mechanisms have been introduced which may explain the nephroprotective effect of sodium glucose cotransporter type 2 inhibitors beyond lowering blood glucose. This current narrative review has the objective to describe main underlying mechanisms causing a nephroprotective effect and to show similarities as well as differences between proposed mechanisms which can be observed in patients with diabetic and nondiabetic chronic kidney disease.

Methods

We performed a narrative review of the literature on Pubmed and Embase. The research string comprised various combinations of items including "chronic kidney disease", "sodium glucose cotransporter 2 inhibitor" and "mechanisms". We searched for original research and review articles published until march, 2022. The databases were searched independently and the agreements by two authors were jointly obtained.

Results

Sodium glucose cotransporter type 2 inhibitors show systemic, hemodynamic, and metabolic effects. Systemic effects include reduction of blood pressure without compensatory activation of the sympathetic nervous system. Hemodynamic effects include restoration of tubuloglomerular feedback which may improve pathologic hyperfiltration observed in most cases with chronic kidney disease. Current literature indicates that SGLT2i may not improve cortical oxygenation and may reduce medullar oxygenation.

Conclusion

Sodium glucose cotransporter type 2 inhibitors cause nephroprotective effects by several mechanisms. However, several mediators which are involved in the underlying pathophysiology may be different between diabetic and nondiabetic patients.

Childhood Obesity: Insight into Kidney Involvement

This review examines the impact of childhood obesity on the kidney from an epidemiological, pathogenetic, clinical, and pathological perspective, with the aim of providing pediatricians and nephrologists with the most current data on this topic. The prevalence of childhood obesity and chronic kidney disease (CKD) is steadily increasing worldwide, reaching epidemic proportions. While the impact of obesity in children with CKD is less pronounced than in adults, recent studies suggest a similar trend in the child population. This is likely due to the significant association between obesity and the two leading causes of end-stage renal disease (ESRD): diabetes mellitus (DM) and hypertension. Obesity is a complex, systemic disease that reflects interactions between environmental and genetic factors. A key mechanism of kidney damage is related to metabolic syndrome and insulin resistance. Therefore, we can speculate about an adipose tissue-kidney axis in which neurohormonal and immunological mechanisms exacerbate complications resulting from obesity. Adipose tissue, now recognized as an endocrine organ, secretes cytokines called adipokines that may induce adaptive or maladaptive responses in renal cells, leading to kidney fibrosis. The impact of obesity on kidney transplant-related outcomes for both donors and recipients is also significant, making stringent preventive measures critical in the pre- and post-transplant phases. The challenge lies in identifying renal involvement as early as possible, as it is often completely asymptomatic and not detectable through common markers of kidney function. Ongoing research into innovative technologies, such as proteomics and metabolomics, aims to identify new biomarkers and is constantly evolving. Many aspects of pediatric disease progression in the population of children with obesity still require clarification. However, the latest scientific evidence in the field of nephrology offers glimpses into various new perspectives, such as genetic factors, comorbidities, and novel biomarkers. Investigating these aspects early could potentially improve the prognosis of these young patients through new diagnostic and therapeutic strategies. Hence, the aim of this review is to provide a comprehensive exploration of the pathogenetic mechanisms and prevalent pathological patterns of kidney damage observed in children with obesity.

Trajectories of eGFR and risk of albuminuria in youth with type 2 diabetes: results from the TODAY cohort study

BACKGROUND

We conducted exploratory analyses to identify distinct trajectories of estimated glomerular filtration rate (eGFR) and their relationship with hyperfiltration, subsequent rapid eGFR decline, and albuminuria in participants with youth-onset type 2 diabetes enrolled in the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study.

METHODS

Annual serum creatinine, cystatin C, urine albumin, and creatinine measurements were obtained from 377 participants followed for ≥ 10 years. Albuminuria and eGFR were calculated. Hyperfiltration peak is the greatest eGFR inflection point during follow-up. Latent class modeling was applied to identify distinct eGFR trajectories.

RESULTS

At baseline, participants' mean age was 14 years, type 2 diabetes duration was 6 months, mean HbA1c was 6%, and mean eGFR was 120 ml/min/1.73 m2. Five eGFR trajectories associated with different rates of albuminuria were identified, including a "progressive increasing eGFR" group (10%), three "stable eGFR" groups with varying starting mean eGFR, and an "eGFR steady decline" group (1%). Participants who exhibited the greatest peak eGFR also had the highest levels of elevated albuminuria at year 10. This group membership was characterized by a greater proportion of female and Hispanic participants.

CONCLUSIONS

Distinct eGFR trajectories that associate with albuminuria risk were identified, with the eGFR trajectory characterized by increasing eGFR over time associating with the highest level of albuminuria. These descriptive data support the current recommendations to estimate GFR annually in young persons with type 2 diabetes and provide insight into eGFR-related factors which may contribute to predictive risk strategies for kidney disease therapies in youth with type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00081328, date registered 2002. A higher resolution version of the Graphical abstract is available as Supplementary information.

Association of high-estimated glomerular filtration rate with the severity of ischemic stroke during non-vitamin K antagonist oral anticoagulants therapy: a nationwide cohort study

Aim

While the relationship between impaired kidney function and non-vitamin K antagonist oral anticoagulants (NOACs) is well established, there is limited research exploring the association between an elevated estimated glomerular filtration rate (eGFR) and the efficacy of NOACs, especially concerning the outcomes of acute ischemic stroke (AIS). This study aimed to examine the association between higher-than-normal eGFR and the severity of AIS during the use of NOACs using a nationwide multicenter stroke registry in Korea.

Material and methods

This study utilized data from the Korean Stroke Registry (KSR) database, examining information from 2,379 patients with AIS, who had atrial fibrillation (AF) and a history of utilizing NOACs prior to hospitalization due to incident stroke occurring between 2016 and 2021. Patients with a history involving two or more types of anticoagulants or one or more forms of antiplatelet agents were excluded. Baseline characteristics, medical history, medication usage, CHADS2-VASc score, and the anticoagulation and risk factors in atrial fibrillation (ATRIA) score were evaluated. Renal function was assessed using eGFR levels and calculated with the Cockcroft-Gault equation. The severity of stroke was measured by the National Institutes of Health Stroke Scale as an outcome. For sensitivity analysis, further evaluation was performed using eGFR levels according to the modification of diet in renal disease (MDRD) study equation.

Results

The mean age of subjects was 76.1 ± 8.9 years. The moderate-to-severe stroke severity group exhibited an elevation in creatinine levels. The eGFR of 60 to 89 mL/min/1.73 m2 group was associated with a decreased risk of moderate-to-severe stroke severity [hazard ratio (HR)] (0.77, 95% confidence interval (CI) [0.61, 0.98], p = 0.031) compared to the eGFR≥90 mL/min/1.73 m2 group. An increment of 10 units in eGFR was marginally associated with an increased risk of moderate-to-severe stroke severity (HR: 1.03, 95% CI [1.00, 1.07], p = 0.054).

Conclusion

The study revealed that individuals with eGFR ≥ 90 mL/min/1.73 m2 had an association linked to an increased risk of moderate-to-severe stroke severity. Our study suggests that patients taking NOACs with higher-than-normal eGFR levels may have an increased severity of AIS.

The Impact of Early-Stage Chronic Kidney Disease on Weight Loss Outcomes After Gastric Bypass

PURPOSE

Weight loss achieved through bariatric metabolic surgery was demonstrated to be effective at reversing chronic kidney dysfunction associated with obesity-related glomerulopathy. However, robust data on how pre-operative kidney status impacts on bariatric metabolic surgery weight loss outcomes is still lacking. The aim of this study was to evaluate the impact of kidney dysfunction on weight loss outcomes after bariatric metabolic surgery.

METHODS

Patients with obesity to be submitted to gastric bypass surgery underwent a pre-operative evaluation of creatinine clearance, estimated glomerular filtration rate (eGFR), proteinuria, and albuminuria in 24-hour urine. Body mass index (BMI), % total weight loss (%TWL), and % excess BMI loss (%EBMIL) were assessed at 6 and 12 months after surgery.

RESULTS

Before surgery, patients (N=127) had a mean BMI of 39.6 ± 3.0 kg/m2, and 56.7% (n=72) had a creatinine clearance > 130 mL/min, 23.6% (n= 30) presented proteinuria > 150 mg/24h, and 15.0% (n= 19) presented albuminuria > 30 mg/24h. After surgery, the mean BMI was 27.7 kg/m2 and 25.0 kg/m2 at 6 and 12 months, respectively (p<0.0001). The %TWL was lower in patients with pre-operative eGFR < percentile 25 (34.4 ± 5.8% vs 39.4 ± 4.9%, p=0.0007, at 12 months). There were no significant correlations between weight loss metrics and pre-operative creatinine clearance rate, proteinuria, or albuminuria.

CONCLUSION

Early-stage chronic kidney disease (G2) has a negative impact on short-term weight loss outcomes after bariatric metabolic surgery, albeit in a magnitude inferior to the clinically relevant threshold.

A physiological approach to renal clearance: From premature neonates to adults

AIMS

We propose using glomerular filtration rate (GFR) as the physiological basis for distinguishing components of renal clearance.

METHODS

Gentamicin, amikacin and vancomycin are thought to be predominantly excreted by the kidneys. A mixed-effects joint model of the pharmacokinetics of these drugs was developed, with a wide dispersion of weight, age and serum creatinine. A dataset created from 18 sources resulted in 27,338 drug concentrations from 9,901 patients. Body size and composition, maturation and renal function were used to describe differences in drug clearance and volume of distribution.

RESULTS

This study demonstrates that GFR is a predictor of two distinct components of renal elimination clearance: (1) GFR clearance associated with normal GFR and (2) non-GFR clearance not associated with normal GFR. All three drugs had GFR clearance estimated as a drug-specific percentage of normal GFR (gentamicin 39%, amikacin 90% and vancomycin 57%). The total clearance (sum of GFR and non-GFR clearance), standardized to 70 kg total body mass, 176 cm, male, renal function 1, was 5.58 L/h (95% confidence interval [CI] 5.50-5.69) (gentamicin), 7.77 L/h (95% CI 7.26-8.19) (amikacin) and 4.70 L/h (95% CI 4.61-4.80) (vancomycin).

CONCLUSIONS

GFR provides a physiological basis for renal drug elimination. It has been used to distinguish two elimination components. This physiological approach has been applied to describe clearance and volume of distribution from premature neonates to elderly adults with a wide dispersion of size, body composition and renal function. Dose individualization has been implemented using target concentration intervention.

Clinical and biochemical footprints of inherited metabolic diseases. XIV. Metabolic kidney diseases

Kidney disease is a global health burden with high morbidity and mortality. Causes of kidney disease are numerous, extending from common disease groups like diabetes and arterial hypertension to rare conditions including inherited metabolic diseases (IMDs). Given its unique anatomy and function, the kidney is a target organ in about 10% of known IMDs, emphasizing the relevant contribution of IMDs to kidney disease. The pattern of injury affects all segments of the nephron including glomerular disease, proximal and distal tubular damage, kidney cyst formation, built-up of nephrocalcinosis and stones as well as severe malformations. We revised and updated the list of known metabolic etiologies associated with kidney involvement and found 190 relevant IMDs. This represents the 14th of a series of educational articles providing a comprehensive and revised list of metabolic differential diagnoses according to system involvement.

Mitochondrial Impairment: A Link for Inflammatory Responses Activation in the Cardiorenal Syndrome Type 4

Cardiorenal syndrome type 4 (CRS type 4) occurs when chronic kidney disease (CKD) leads to cardiovascular damage, resulting in high morbidity and mortality rates. Mitochondria, vital organelles responsible for essential cellular functions, can become dysfunctional in CKD. This dysfunction can trigger inflammatory responses in distant organs by releasing Damage-associated molecular patterns (DAMPs). These DAMPs are recognized by immune receptors within cells, including Toll-like receptors (TLR) like TLR2, TLR4, and TLR9, the nucleotide-binding domain, leucine-rich-containing family pyrin domain-containing-3 (NLRP3) inflammasome, and the cyclic guanosine monophosphate (cGMP)-adenosine monophosphate (AMP) synthase (cGAS)-stimulator of interferon genes (cGAS-STING) pathway. Activation of these immune receptors leads to the increased expression of cytokines and chemokines. Excessive chemokine stimulation results in the recruitment of inflammatory cells into tissues, causing chronic damage. Experimental studies have demonstrated that chemokines are upregulated in the heart during CKD, contributing to CRS type 4. Conversely, chemokine inhibitors have been shown to reduce chronic inflammation and prevent cardiorenal impairment. However, the molecular connection between mitochondrial DAMPs and inflammatory pathways responsible for chemokine overactivation in CRS type 4 has not been explored. In this review, we delve into mechanistic insights and discuss how various mitochondrial DAMPs released by the kidney during CKD can activate TLRs, NLRP3, and cGAS-STING immune pathways in the heart. This activation leads to the upregulation of chemokines, ultimately culminating in the establishment of CRS type 4. Furthermore, we propose using chemokine inhibitors as potential strategies for preventing CRS type 4.

Usefulness of Alternative Therapy with Hydrocortisone in the Postoperative Management of Severe Primary Aldosteronism

Mineralocorticoid deficiency (MD) with hyperkalemia is an important complication of adrenalectomy in patients with primary aldosteronism (PA). We herein report a 52-year-old man with refractory hypertension, hypokalemia, and severe renal dysfunction due to PA caused by a right adrenal adenoma. His estimated glomerular filtration rate (eGFR) transiently increased immediately after adrenalectomy but then gradually declined, and he developed hyperkalemia. A postoperative endocrine examination revealed MD. Considering the patient's hypertension and severe renal dysfunction, we administered hydrocortisone instead of fludrocortisone, which improved the hyperkalemia and stopped the decline in the eGFR. Alternative therapy with hydrocortisone may be useful in such patients with MD.

Efficacy and Safety of Sodium-Glucose Cotransporter-2 Inhibitors in Nondiabetic Patients with Chronic Kidney Disease: A Review of Recent Evidence

Background

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) were initially developed as glucose-lowering agents in patients with type-2 diabetes. However, available data from clinical trials and meta-analyses suggest that SGLT2i have pleiotropic benefits in reducing mortality and delaying the progression of chronic kidney disease (CKD) in both diabetic and nondiabetic patients. Thus, we herein review the current evidence regarding the efficacy and safety of SGLT2i in patients with nondiabetic CKD and appraise the recently reported clinical trials that might facilitate the management of CKD in routine clinical practice.

Summary

The benefits of SGLT2i on nondiabetic CKD are multifactorial and are mediated by a combination of mechanisms. The landmark DAPA-CKD trial revealed that dapagliflozin administered with renin-angiotensin system blockade drugs reduced the risk of a sustained decline (at least 50%) in the estimated glomerular filtration rate, end-stage kidney disease, or death from cardiorenal causes. The recent EMPA-KIDNEY trial showed that empagliflozin therapy led to a lower risk of progression of kidney disease or death from cardiovascular causes. These benefits were consistent in patients with and without diabetes. Moreover, a meta-analysis of DAPA-HF and EMPEROR-Reduced trials confirmed reductions in the combined risk of cardiovascular death or worsening heart failure including composite renal endpoint.

Key Messages

Considering the robust data available from DAPA-CKD, EMPA-KIDNEY, and other trials such as EMPEROR-Preserved, DIAMOND that included nondiabetic patients, it may be necessary to update current guidelines to include SGLT2i as a first-line therapy for CKD and reevaluate current CKD therapeutic approaches.

Prescription of DOACs in Patients with Atrial Fibrillation at Different Stages of Renal Insufficiency

Atrial fibrillation (AF) and renal insufficiency often coexist and are increasingly prevalent with advancing age. Both the risk of thromboembolic events and bleeding propensity are higher in patients with AF and impaired renal function versus those with good renal health. Direct oral anticoagulants (DOACs) are being increasingly preferred over vitamin K antagonists (VKAs) in the treatment of patients with AF and impaired renal function as VKAs may accelerate progression of chronic kidney disease. DOACs, however, are eliminated by the kidneys to varying degrees, and their dosages must be adapted in accordance with renal function. Since creatinine clearance (CrCl) monitoring is recommended in patients with AF receiving DOAC therapy, CrCl must be routinely monitored in patients at the start and during the course of anticoagulation to avoid deviation from Summary of Product Characteristics dosage specifications. This review article provides an overview of current knowledge on the selection and dose of DOACs including apixaban, dabigatran, edoxaban and rivaroxaban in AF patients at different stages of renal insufficiency, with a special focus on elderly patients with comorbidities and receiving multiple medications. The groups discussed in this review include patients with varying levels of CrCl including hyperfiltration or CrCl > 90 ml/min, CrCl < 90-50 ml/min, CrCl < 50-30 ml/min, CrCl < 30-15 ml/min and end-stage renal disease or on dialysis.

Dose decision of HSK7653 oral immediate release tablets in specific populations clinical trials based on mechanistic physiologically-based pharmacokinetic model

HSK7653, an oral dipeptidyl peptidase-4 inhibitor administered every 2 weeks, is a candidate for the treatment of type 2 diabetes mellitus. The major elimination pathway of HSK7653 in vivo is renal excretion, and hepatic metabolism and fecal excretion of unchanged compound contribute less to the systemic clearance of HSK7653. Considering the disposition characteristics and the potential indication population of HSK7653, evaluating the HSK7653 exposure in patients with renal impairment and geriatric populations is a prerequisite for bringing more benefits to the patients. Here, a PBPK model was developed based on in vitro experimental results, such as dissolution, permeability, and metabolism, and the in vivo renal clearance, to evaluate the effects of physiological factors and food on HSK7653 exposure in specific populations, including adult and elder individuals with renal impairment and geriatric populations. Simulation results showed that the AUC of HSK7653 increased by 46%, 82%, and 129% in adult patients with mild, moderate, and severe renal impairment, and by 56%, 78%, and 101% in patients aged 65-75, 75-85 and 85-95 years, respectively. The AUC increased in the range of 62%-83%, 98%-133%, and 153%-195% in elderly patients (65-95 years) with mild, moderate, and severe renal impairment, respectively. Moreover, two different absorption model development methods (dissolution profile method and the diffusion layer model method) predicted that food had no effect on the exposure of the same simulated population. Since the predicted AUC of HSK7653 at the 10 mg dose in various specific populations was still within the relatively flat results of the exposure-response analysis, the 10 mg dose of HSK7653 was first used to explore the exposure in the renal impairment population (CTR20221952).

Pharmacokinetic relevance of glomerular hyperfiltration for drug dosing

In chronic kidney disease (CKD) patients, hypofiltration may lead to the accumulation of drugs that are cleared mainly by the kidney and, vice versa, hyperfiltration may cause augmented renal excretion of the same drugs. In this review we mainly focus on the issue of whether hyperfiltration significantly impacts the renal clearance of drugs and whether the same alteration may demand an up-titration of the doses applied in clinical practice. About half of severely ill, septic patients and patients with burns show glomerular hyperfiltration and this may lead to enhanced removal of drugs such as hydrophilic antibiotics and a higher risk of antibiotic treatment failure. In general, hyperfiltering obese individuals show higher absolute drug clearances than non-obese control subjects, but this depends on the body size descriptor adopted to adjust for fat excess. Several mechanisms influence pharmacokinetics in type 2 diabetes, including renal hyperfiltration, reduced tubular reabsorption and augmented tubular excretion. However, no consistent pharmacokinetic alteration has been identified in hyperfiltering obese subjects and type 2 diabetics. Non-vitamin K antagonist oral anticoagulants (NOACs) have exhibited lower plasma concentrations in hyperfiltering patients in some studies in patients with atrial fibrillation, but a recent systematic review failed to document any excess risk for stroke and systemic embolism in these patients. Hyperfiltration is common among severely ill patients in intensive care units and drug levels should be measured whenever possible in these high-risk patients to prevent underdosing and treatment failure. Hyperfiltration is also common in patients with obesity or type 2 diabetes, but no consistent pharmacokinetic alteration has been described in these patients. No NOAC dose adjustment is indicated in patients with atrial fibrillation being treated with these drugs.

Association of eGFR and mortality with use of a joint model: results of a nationwide study in Iceland

OBJECTIVES

Prior studies on the association of estimated glomerular filtration rate (eGFR) and mortality have failed to include methods to account for repeated eGFR determinations. The aim of this study was to estimate the association between eGFR and mortality in the general population in Iceland employing a joint model.

METHODS

We obtained all serum creatinine and urine protein measurements from all clinical laboratories in Iceland in the years 2008-16. Clinical data were obtained from nationwide electronic medical records. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation and categorized as follows: 0-29, 30-44, 45-59, 60-74, 75-89, 90-104 and >104 mL/min/1.73 m2. A multiple imputation method was used to account for missing urine protein data. A joint model was used to assess risk of all-cause mortality.

RESULTS

We obtained 2 120 147 creatinine values for 218 437 individuals, of whom 84 364 (39%) had proteinuria measurements available. Median age was 46 (range 18-106) years and 47% were men. Proteinuria associated with increased risk of death for all eGFR categories in persons of all ages. In persons ≤65 years, the lowest risk was observed for eGFR of 75-89 mL/min/1.73 m2 without proteinuria. For persons aged >65 years, the lowest risk was observed for eGFR of 60-74 mL/min/1.73 m2 without proteinuria. eGFR of 45-59 mL/min/1.73 m2 without proteinuria did not associate with increased mortality risk in this age group. eGFR >104 mL/min/1.73 m2 associated with increased mortality.

CONCLUSIONS

These results lend further support to the use of age-adapted eGFR thresholds for defining chronic kidney disease. Very high eGFR needs to be studied in more detail with regard to mortality.

Long-Term Renal Function in Adult Patients with Phenylketonuria

INTRODUCTION

In phenylketonuria (PKU), toxic phenylalanine (Phe) can harm other organs beyond the brain. Furthermore, the lifelong therapy of PKU consists of consumption of increased amounts of amino-acid mixture that provoke hyperfiltration in the glomeruli. Therefore, the adherence to therapy in PKU might influence the long-term kidney function in PKU patients.

METHODS

Data from 41 adult, early treated PKU patients were analyzed in this 10-year, retrospective, monocentric study. Two subgroups were created according to their therapy adherence: one with long-term blood Phe levels in the therapeutic range (<600 µmol/L), and one with suboptimal blood Phe levels. Renal function and metabolic parameters were collected over 10 years. Kidney function parameters were compared between the two groups and associations between blood Phe levels and kidney function were tested.

RESULTS

After 10 years, serum creatinine levels (p = 0.369) and estimated glomerular filtration rate (eGFR) (p = 0.723) did not change significantly from baseline in the good therapeutic group. The suboptimal therapeutic group's eGFR decreased in the same period (from 110.4 ± 14 mL/min/1.73 m2 to 94.2 ± 16 mL/min/1.73 m2, p = 0.017). At 10 years, the suboptimal therapeutic group had an increased serum creatinine level (81 ± 14.4 μmol/L vs. 71.5 ± 13 μmol/L, p = 0.038), and a decreased eGFR (94.2 ± 16 mL/min/1.73 m2 vs. 103.3 ± 13 mL/min/1.73 m2p = 0.031) compared to the good adhering group. Significant negative correlation between Phe levels and eGFR (r = -0.41, p = 0.008) was observed.

CONCLUSION

Long-term suboptimal therapy adherence in PKU patients with high blood Phe levels may lead to deterioration in 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.

The Triglyceride-Glucose Index is Independently Associated with Chronic Kidney Disease in the Geriatric Population, Regardless of Obesity and Sex

BACKGROUND

Insulin resistance (IR) negatively affects several risk factors of chronic kidney disease (CKD). This cross-sectional study investigated whether the triglyceride-glucose (TyG) index, which reflects IR, was independently associated with CKD in a geriatric population, regardless of obesity and sex.

METHODS

The analysis included 7,326 individuals (2,864 males and 4,462 females) aged ≥60 years. Non-obesity or obesity was evaluated using a body mass index cutoff of 25 kg/m2. The TyG index was calculated as ln [triglyceride concentration (mg/dL)×fasting plasma glucose concentration (mg/dL)]/2. All participants were categorized into three groups according to TyG tertiles. Moderate-to-severe CKD (MSCKD) was defined as an estimated glomerular filtration rate (eGFR) of <45.0 mL/min/1.73 m2.

RESULTS

In males and females with or without obesity, a trend test showed a decreasing tendency in the eGFR from the lowest to highest TyG tertiles. Males without obesity and females with obesity in the middle and highest tertiles of the TyG index were 2.342 and 2.393, and were 2.313 and 3.516 times more likely to have MSCKD, respectively. Those with or without obesity in the highest tertile of the TyG index were 1.736 and 2.374 times more likely to have MSCKD, respectively.

CONCLUSION

Geriatric populations with an increased TyG index have a high risk of MSCKD regardless of obesity and sex. Our findings suggest that increased IR is associated with CKD in the geriatric population independent of obesity and sex.

Association of high estimated glomerular filtration rate with risk of atrial fibrillation: a nationwide cohort study

Aim

While the relationship between impaired kidney function and atrial fibrillation (AF) is well established, there is limited research exploring the association between elevated estimated glomerular filtration rate (eGFR) and AF development. This study aimed to examine the association between higher-than-normal eGFR and AF risk using a nationwide longitudinal study of the general population in Korea.

Materials and methods

This study utilized the National Health Insurance Service cohort database of Korea, analyzing data from 2,645,042 participants aged 20-79 years who underwent health examinations between 2010 and 2011. Participants with a history of end-stage renal disease, renal transplantation, and AF prior to the index date were excluded. Renal function was assessed using eGFR levels, calculated with the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Baseline characteristics were gathered through questionnaires, while comorbidities and AF occurrence outcomes were identified and validated using diagnostic codes and medication histories. The study employed Kaplan-Meier survival curves and Cox proportional hazard models to evaluate the association between eGFR and AF occurrence.

Results

The mean age of subjects was 48.82 ± 10.08 years. Over a median follow-up of 9.58 years, 27,469 (1.04%) AF cases were identified. The risk for AF increased in the higher-than-normal decile, as demonstrated by Kaplan-Meier survival curves (p < 0.001). The eGFR <30 mL/min/1.73 m2 group was associated with an increased risk of AF [hazard ratio (HR): 1.22, 95% confidence interval (CI) (1.01, 1.46), p = 0.039], while the eGFR >120 mL/min/1.73 m2 group was associated with a decreased risk of AF [HR: 0.88, 95% CI (0.78, 0.98), p = 0.045]. Compared to the 5th decile, the 1st [HR: 1.08, 95% CI (1.03, 1.13), p = 0.010] eGFR decile was significantly associated with an increased risk of AF, while the 10th [HR: 0.77, 95% CI (0.70, 0.85), p < 0.001] eGFR decile was significantly associated with a reduced risk of AF.

Conclusion

The study revealed that individuals with eGFR>120 mL/min/1.73 m2 or those falling within eGFR 10th decile (>113.41 mL/min/1.73 m2) demonstrated an inverse association linked to a reduced risk of AF. Our study suggests that general population with higher-than-normal eGFR levels may have a lower risk of developing AF.

Dietary magnesium is able to influence the relationship between vitamin C and estimated glomerular filtration rate: A cross-sectional study

The estimated glomerular filtration rate (eGFR) is a comprehensive index that is widely used to assess renal function. Although studies have confirmed a correlation between eGFR and dietary vitamin C, the impact of varying levels of vitamin C on eGFR remains unclear. Additionally, the interaction between dietary magnesium intake and vitamin C concentration on eGFR is not well understood. As such, the objective of this study was to investigate the relationship between dietary magnesium intake and vitamin C in relation to eGFR. This study analyzed the data of consecutive NHANES from 2005 to 2018. We included 17,633 participants aged 20 or older and used multiple linear regression analysis to evaluate the relationship between dietary vitamin C and eGFR. Dietary Mg intake from experimental data was dichotomized into a low dietary Mg intake group (≤254 mg/day) and a normal dietary Mg intake group (>254 mg/day). To evaluate the impact of dietary magnesium intake on eGFR, a multivariable linear regression was conducted utilizing an interaction test between dietary vitamin C and eGFR. We discovered a positive association between dietary vitamin C content and eGFR. The relationship between dietary vitamin C levels and eGFR differed between individuals with low Mg intake and those with normal Mg intake (β: 2.96 95% CI:1.63 ~ 4.29 vs. β: 1.05 95% CI: -0.15 to 2.25), and the positive association of high dietary vitamin C content with eGFR was stronger in the low Mg intake group. Furthermore, we observed that dietary magnesium intake significantly altered the positive association between dietary vitamin C and eGFR (interaction value of 0.020). Our experimental study revealed that the interaction between dietary magnesium and dietary vitamin C can significantly impact eGFR. This finding carries significant implications for the treatment of diseases resulting from abnormal eGFR, as well as the selection of clinically relevant drugs.

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

Background

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

Methods

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

Results

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

Conclusion

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

Glomerular hyperfiltration and hypertrophy: an evaluation of maximum values in pathological indicators to discriminate "diseased" from "normal"

The success of sodium-glucose cotransporter 2 inhibitors and bariatric surgery in patients with chronic kidney disease has highlighted the importance of glomerular hyperfiltration and hypertrophy in the progression of kidney disease. Sustained glomerular hyperfiltration and hypertrophy can lead to glomerular injury and progressive kidney damage. This article explores the relationship between obesity and chronic kidney disease, focusing on the roles of glomerular hyperfiltration and hypertrophy as hallmarks of obesity-related kidney disease. The pathological mechanisms underlying this association include adipose tissue inflammation, dyslipidemia, insulin resistance, chronic systemic inflammation, oxidative stress, and overactivation of the sympathetic nervous system, as well as the renin-angiotensin aldosterone system. This article explains how glomerular hyperfiltration results from increased renal blood flow and intraglomerular hypertension, inducing mechanical stress on the filtration barrier and post-filtration structures. Injured glomeruli increase in size before sclerosing and collapsing. Therefore, using extreme values, such as the maximal glomerular diameter, could improve the understanding of the data distribution and allow for better kidney failure predictions. This review provides important insights into the mechanisms underlying glomerular hyperfiltration and hypertrophy and highlights the need for further research using glomerular size, including maximum glomerular profile, calculated using needle biopsy specimens.

A State-of-the-Science Review of Interactions of Per- and Polyfluoroalkyl Substances (PFAS) with Renal Transporters in Health and Disease: Implications for Population Variability in PFAS Toxicokinetics

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and have been shown to cause various adverse health impacts. In animals, sex- and species-specific differences in PFAS elimination half-lives have been linked to the activity of kidney transporters. However, PFAS molecular interactions with kidney transporters are still not fully understood. Moreover, the impact of kidney disease on PFAS elimination remains unclear.

OBJECTIVES

This state-of-the-science review integrated current knowledge to assess how changes in kidney function and transporter expression from health to disease could affect PFAS toxicokinetics and identified priority research gaps that should be addressed to advance knowledge.

METHODS

We searched for studies that measured PFAS uptake by kidney transporters, quantified transporter-level changes associated with kidney disease status, and developed PFAS pharmacokinetic models. We then used two databases to identify untested kidney transporters that have the potential for PFAS transport based on their endogenous substrates. Finally, we used an existing pharmacokinetic model for perfluorooctanoic acid (PFOA) in male rats to explore the influence of transporter expression levels, glomerular filtration rate (GFR), and serum albumin on serum half-lives.

RESULTS

The literature search identified nine human and eight rat kidney transporters that were previously investigated for their ability to transport PFAS, as well as seven human and three rat transporters that were confirmed to transport specific PFAS. We proposed a candidate list of seven untested kidney transporters with the potential for PFAS transport. Model results indicated PFOA toxicokinetics were more influenced by changes in GFR than in transporter expression.

DISCUSSION

Studies on additional transporters, particularly efflux transporters, and on more PFAS, especially current-use PFAS, are needed to better cover the role of transporters across the PFAS class. Remaining research gaps in transporter expression changes in specific kidney disease states could limit the effectiveness of risk assessment and prevent identification of vulnerable populations. https://doi.org/10.1289/EHP11885.

Comparative analysis of mortality and progression to end-stage renal disease between surgically induced and medical chronic kidney disease: A study using the National Health Insurance customized database

PURPOSE

We aimed to compare the mortality rate and the risk for progression to end-stage renal disease (ESRD) and cardiovascular disease (CVD) between patients who underwent surgery for localized renal cell carcinoma (RCC) and those with chronic kidney disease (CKD) without surgery by investigating the National Health Insurance Service.

MATERIALS AND METHODS

The surgical group (CKD-S) included patients who underwent radical or partial nephrectomy for RCC from 2007 to 2009. Grades of surgical CKD were classified according to the estimated glomerular filtration rate (eGFR) measured at a health screening within 2 years after surgery. The nonsurgical group (CKD-M) was graded according to the eGFR in the 2009-2010 health screenings. We performed 1:5 propensity score matching for age, gender, diabetes, hypertension, Charlson comorbidity index, smoking, alcohol consumption, baseline eGFR, and body mass index.

RESULTS

A total of 8,698 patients (CKD-S, n=1,521; CKD-M, n=7,177) were analyzed. The CKD-M group was at higher risk for progression to ESRD (hazard ratio [HR] 1.90, 95% confidence interval [CI] 1.04-3.44, p=0.036) and CVD (HR 1.17, 95% CI 1.06-1.29, p=0.002) than the CKD-S group. In the group of patients with grade 3 disease or higher, the CKD-M group was at significantly higher risk for progression to ESRD (HR 2.21, 95% CI 1.47-3.31, p<0.001), CVD (HR 1.32, 95% CI 1.20-1.45, p<0.001), and overall mortality (HR 1.50, 95% CI 1.21-1.86, p<0.001).

CONCLUSIONS

The risk for progression to ESRD, CVD, or mortality in patients with CKD-S may be lower than in patients with CKD-M.

Cross-phenotype association analysis of gastric cancer: in-silico functional annotation based on the disease-gene network

BACKGROUND

A gene or variant has pleiotropic effects, and genetic variant identification across multiple phenotypes can provide a comprehensive understanding of biological pathways shared among different diseases or phenotypes. Discovery of genetic loci associated with multiple diseases can simultaneously support general interventions. Several meta-analyses have shown genetic associations with gastric cancer (GC); however, no study has identified associations with other phenotypes using this approach.

METHODS

Here, we applied disease network analysis and gene-based analysis (GBA) to examine genetic variants linked to GC and simultaneously associated with other phenotypes. We conducted a single-nucleotide polymorphism (SNP) level meta-analysis and GBA through a systematic genome-wide association study (GWAS) linked to GC, to integrate published results for the SNP variants and group them into major GC-associated genes. We then performed disease network and expression quantitative trait loci (eQTL) analyses to evaluate cross-phenotype associations and expression levels of GC-related genes.

RESULTS

Seven genes (MTX1, GBAP1, MUC1, TRIM46, THBS3, PSCA, and ABO) were associated with GC as well as blood urea nitrogen (BUN), glomerular filtration rate (GFR), and uric acid (UA). In addition, 17 SNPs regulated the expression of genes located on 1q22, 24 SNPs regulated the expression of PSCA on 8q24.3, and rs7849820 regulated the expression of ABO on 9q34.2. Furthermore, rs1057941 and rs2294008 had the highest posterior causal probabilities of being a causal candidate SNP in 1q22, and 8q24.3, respectively.

CONCLUSIONS

These findings identified seven GC-associated genes exhibiting a cross-association with GFR, BUN, and UA.

Protein Biomarkers in Chronic Kidney Disease in Children-What Do We Know So Far?

Chronic kidney disease (CKD) in children is a major concern of medical care and public health as it is related to high morbidity and mortality due to progression to end-stage kidney disease (ESKD). It is essential to identify patients with a risk of developing CKD to implement therapeutic interventions. Unfortunately, conventional markers of CKD, such as serum creatinine, glomerular filtration rate (GFR) and proteinuria, have many limitations in serving as an early and specific diagnostic tool for this condition. Despite the above, they are still the most frequently utilized as we do not have better. Studies from the last decade identified multiple CKD blood and urine protein biomarkers but mostly assessed the adult population. This article outlines some recent achievements and new perspectives in finding a set of protein biomarkers that might improve our ability to prognose CKD progression in children, monitor the response to treatment, or even become a potential therapeutic target.

Association between triglyceride-glucose index and chronic kidney disease: A cohort study and meta-analysis

BACKGROUND AND AIMS

Nowadays, the relationship between triglyceride-glucose (TyG) index and chronic kidney disease (CKD) is still controversial. We aimed to prospectively investigate the relationship between TyG index and CKD in a cohort and meta-analysis.

METHODS AND RESULTS

A total of 10498 participants from the China Health and Retirement Longitudinal Study (CHARLS) were included. Participants were divided into four groups based on the quartiles of the TyG index. CKD was based on self-reported physicians' diagnosis or personal eGFR level. A cox regression model was established to analyze the correlation between TyG index and CKD. A meta-analysis was conducted to incorporate the results of the current study and previous studies on the association of TyG index with CKD. In multivariable-adjusted analyses, the adjusted hazard ratio (95% confidence interval) for the highest versus lowest quartile of TyG index was 1.30 (1.08-1.57). Each 1-SD higher TyG index was associated with an increased risk of 11% (HR 1.11, 95% CI 1.03-1.19). The meta-analysis further confirmed the significant associations between TyG and CKD and pooled relative risk for highest vs lowest TyG index quartile was 1.47 (1.32-1.63).

CONCLUSIONS

Higher TyG index was associated with increased risk of CKD, independently of established risk factors. The TyG index may be a predictor of incident CKD.

Protective effects of long-term nitrate administration against ovariectomy-induced kidney dysfunction in rats

BACKGROUND

Menopause is associated with higher risks of chronic kidney disease. We determined the effect of nitrate on ovariectomy-induced kidney dysfunction METHODS: Control, ovariectomized (OVX), control + nitrate, and OVX + nitrate female Wistar rats (n = 10/group); sodium nitrate (100 mg/L) administered in drinking water for 9 months. Glomerular filtration rate (GFR) and albumin excretion rate (AER) were calculated from serum and urine parameters. At month 9, serum and kidney levels of nitric oxide (NO) metabolites (NOx), oxidative stress indices, and mRNA expression of endothelial NO synthase (eNOS) were measured; with histological analyses of the kidney.

RESULTS

Compared to controls, OVX rats had lower GFR (31%, p = 0.0079), higher glomerular tuft volume (30%, p = 0.0402), and Bowman's capsule space (39%, p = 0.0224). OVX rats had lower serum NOx (33%, p = 0.0061) and kidney eNOS mRNA expression (34%, p = 0.0368). Nitrate administration to: (i) control rats increased serum NOx (59%, p < 0.0001), with no effect on other parameters; (ii) OVX rats increased serum (85%, p < 0.0001) and kidney (106%, p = 0.0008) NOx values, and restored kidney eNOS expression to normal value. Nitrate administration to OVX rats increased GFR (36%, p = 0.0361) and restored glomerular tuft volume and Bowman's capsule space to normal values. In OVX rats, it also increased serum catalase (CAT) activity, serum and kidney total antioxidant capacity (TAC), and decreased serum malondialdehyde (MDA).

CONCLUSIONS

Low-dose long-term nitrate administration protects against ovariectomy-induced kidney dysfunction in rats. This effect is associated with reducing ovariectomy-induced oxidative stress and restoring eNOS-derived NO deficiency in systemic circulation and the kidney.

Therapeutic Potential of Targeting Complement C5a Receptors in Diabetic Kidney Disease

Diabetic kidney disease (DKD) affects 30-40% of patients with diabetes and is currently the leading cause of end-stage renal disease (ESRD). The activation of the complement cascade, a highly conserved element of the innate immune system, has been implicated in the pathogenesis of diabetes and its complications. The potent anaphylatoxin C5a is a critical effector of complement-mediated inflammation. Excessive activation of the C5a-signalling axis promotes a potent inflammatory environment and is associated with mitochondrial dysfunction, inflammasome activation, and the production of reactive oxygen species. Conventional renoprotective agents used in the treatment of diabetes do not target the complement system. Mounting preclinical evidence indicates that inhibition of the complement system may prove protective in DKD by reducing inflammation and fibrosis. Targeting the C5a-receptor signaling axis is of particular interest, as inhibition at this level attenuates inflammation while preserving the critical immunological defense functions of the complement system. In this review, the important role of the C5a/C5a-receptor axis in the pathogenesis of diabetes and kidney injuries will be discussed, and an overview of the status and mechanisms of action of current complement therapeutics in development will be provided.

Long-term impact of pregnancy on renal function among Egyptian women with lupus nephritis: A case control study

Few studies tackled the long-term effect of pregnancy on lupus nephritis (LNs); thus, the study aimed to explore the long-term impact of pregnancy on renal outcomes in Egyptian patients with LN. Group I patients included females who had their first pregnancy after LN onset with ≥5 years elapsing after delivery; group II patients included females who had never got pregnant for ≥7 years after LN onset. Data were retrospectively collected at baseline (T₀) and the last visit (T_last). The study included 43 patients in group I and 39 patients in group II. The comparisons between the two groups regarding the characteristics at T_last showed no significant difference regarding the serum creatinine, estimated glomerular filtration rate (eGFR), renal component of SLICC/ACR Damage Index (SDI) as well as the rate of renal flares, new-onset chronic kidney disease (CKD), progressed CKD and end-stage renal disease. Multivariate regression analysis revealed that systemic hypertension and renal flares were predictors of new-onset/progressed CKD (p = 0.019, OR [95% CI] = 4 [1.3-13]; and 0.022, 13.8 [1.5-128.8], respectively) while pregnancy was not (p = 0.363). Paired comparisons between T₀ and T_last characteristics within each group revealed significant increment of serum creatinine, renal SDI and CKD prevalence; as well as decrement of eGFR in group I (p = 0.004, <0.001, 0.001 and <0.001, respectively) and group II (p = 0.006, <0.001, 0.004 and 0.002, respectively). In conclusion, pregnancy, per se, does not affect the long-term renal outcome in LN patients; however, it is rather dependent on the existence of baseline renal damage and the development of renal flares.

Association of urine phthalate metabolites levels with kidney function in 1610 US adolescents

Phthalates are widely used as plasticizer or fragrance ingredients in various consumer products worldwide. However, evidence for the overall effects of mixed exposure to phthalate on kidney function has not been widely investigated. The purpose of this article was to assess the association of urine phthalate metabolite levels and kidney injury parameters in adolescents. We used data from the combined 2007-2016 National Health and Nutrition Examination Survey (NHANES). We fitted weighted linear regressions and Bayesian kernel machine regressions (BKMR) models to explore the association of urinary phthalate metabolites with four parameters of kidney function after adjusting for covariates. Weighted linear regression models showed that MiBP (β = 8.057; P_FDR = 0.016) was significantly positively associated with eGFR and MEP (β = -0.799; P_FDR < 0.001) was significantly negatively correlated with BUN. BKMR analysis showed that the higher the concentration of phthalate metabolite mixture, the higher eGFR in adolescents. Based on the results of these two models, our findings revealed that mixed exposure to phthalates was associated with elevated eGFR in adolescents. However, as the study is cross-sectional, reverse causality is possible, and altered kidney function may impact the concentration of phthalate metabolites in urine.

A profile of SGLT-2 inhibitors in hyponatremia: The evidence to date

Hyponatremia is the most common electrolyte disorder in clinical practice, which may lead to life-threatening complications. Several lines of evidence suggest that hyponatremia is associated not only with significant increases in length of stay, cost, and financial burden, but also with increased morbidity and mortality. Hyponatremia is also considered to be a negative prognostic factor in patients with heart failure and cancer. Although multiple therapeutic methods are available for treating hyponatremia, most have some limitations, such as poor compliance, rapid correction of serum Na⁺, other negative side effects and high cost. Given these limitations, identifying novel therapies for hyponatremia is essential. Recent clinical studies have shown that SGLT-2 inhibitors (SGLT 2i) significantly increased serum Na⁺ levels and were well tolerated by patients who underwent this treatment. Therefore, oral administration of SGLT 2i appears to be an effective treatment for hyponatremia. This article will briefly review the etiology of hyponatremia and integrated control of sodium within the kidney, current therapies for hyponatremia, potential mechanisms and efficacy of SGLT 2i for hyponatremia, and the benefits in cardiovascular, cancer, and kidney disease by regulating sodium and water balance.

Candidate biomarkers as predictors of future kidney disease and cardiovascular dysfunction in adolescents with type 2 diabetes

AIMS

Evaluate changes in circulating biomarkers as predictors of kidney disease, and cardiac/vascular dysfunction in participants from the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study.

METHODS

Candidate biomarkers were assessed annually in 507 participants over a mean follow-up of 6.9 ± 2.4 years. Moderate albuminuria was defined as urine albumin-to-creatinine ratio ≥ 30 mg/g and hyperfiltration as eGFR ≥ 135 mL/min/1.73 m2 at two consecutive visits. Echocardiography (n = 256) and pulse wave velocity (n = 193) were evaluated twice, 5 years apart. Adjusted Cox proportional hazard models and logistic regression models were used to examine associations between biomarkers and outcomes.

RESULTS

At baseline, 35.7% were male, with a mean age 13.9 years, diabetes duration 7.8 months, and HbA1c 6.0%. Higher concentrations of E-selectin and proinsulin were associated with incident moderate albuminuria and hyperfiltration. Higher concentrations of FGF-23 were associated with lower risk of hyperfiltration and negatively correlated with eGFR. No candidate biomarkers predicted a decline in cardiac or vascular function.

CONCLUSIONS

Circulating biomarkers of endothelial dysfunction and markers of β-cell dysfunction and insulin sensitivity could be used in a more personalized risk assessment of kidney disease in youth-onset type 2 diabetes. However, biomarkers studied have limited value in predicting cardiac dysfunction or vascular stiffness.

Sex-specific association of body mass index and fatty liver index with prevalence of renal hyperfiltration: a cross sectional study using Japanese health check-up data

BACKGROUND

The relationship between obesity and nonalcoholic fatty liver disease and renal hyperfiltration is controversial. This study aimed to assess the correlations of body mass index and fatty liver index, respectively, with renal hyperfiltration in non-diabetic subjects, considering age, sex, and body surface area.

METHODS

This cross-sectional study assessed the Japanese health check-up data (FY2018) of 62,379 non-diabetic individuals from a health insurance database. Renal hyperfiltration is the ≥ 95th percentile of estimated glomerular filtration rate (derived by Chronic Kidney Disease Epidemiology Collaboration formula) by gender and age in healthy subjects. After adjusting for potential confounders, multiple logistic regression models were applied to evaluate the correlation of renal hyperfiltration with body mass index categories and fatty liver index (10 equal parts).

RESULTS

A negative and positive correlation, respectively, were noted when the body mass index was < 21 and ≥ 30 in women; however, a positive correlation was noted for BMI < 18.5 and ≥ 30 in men. Renal hyperfiltration prevalence increased when fatty liver index increased for both sexes; the cutoff value for fatty liver index was 14.7 for women and 30.4 for men.

CONCLUSIONS

Body mass index and renal hyperfiltration correlated linearly in women; however, in men, the correlation was U-shaped; therefore, differing by sex. However, fatty liver index correlated linearly with renal hyperfiltration in both sexes. Non-alcoholic fatty liver disease might be associated with renal hyperfiltration; Fatty liver index is a simple marker that can be obtained from health check-ups. Since a high fatty liver index correlated with renal hyperfiltration, it may be beneficial to monitor the renal function in such a population.