Glomerular hyperfiltration: definitions, mechanisms and clinical implications

Glomerular diameter is associated with a reduction in urinary protein by treatment with dapagliflozin in patients with chronic kidney disease

BACKGROUND

Several clinical trials showed that sodium-glucose cotransporter 2 (SGLT2) inhibitors have protective effects against chronic kidney disease (CKD) in both patients with and those without type 2 diabetes mellitus. Since one of the renoprotective mechanisms of SGLT2 inhibitors is thought to be amelioration of glomerular hyperfiltration, we hypothesized that an enlarged glomerular diameter, which suggests increased single-nephron glomerular filtration rate, is associated with a reduction in urinary protein after treatment with an SGLT2 inhibitor.

METHODS

This study was a retrospective multicentered study including 28 adult patients with CKD who underwent kidney biopsy and were then treated with dapagliflozin, an SGLT2 inhibitor. The association of glomerular diameter with changes in urinary protein 4-8 weeks after the initiation of treatment with dapagliflozin was investigated.

RESULTS

Maximum glomerular diameter was significantly and positively correlated with change in urinary protein-to-creatinine ratio (UPCR) (R2 = 0.44; P < 0.001). Maximum glomerular diameter was significantly larger in patients who achieved ≥ 30% reduction in UPCR after the initiation of treatment with dapagliflozin than in patients who achieved < 30% reduction in UPCR (219.4 ± 23.9 vs. 188.0 ± 29.0; P = 0.005). After adjustment of age, sex and estimated glomerular filtration rate, maximum glomerular diameter was independently associated with change in UPCR (β = 0.645, P < 0.001). Furthermore, maximum glomerular diameter was independently associated with ≥ 30% reduction in UPCR (odds ratio: 1.07, 95% confidential interval: 1.01-1.14).

CONCLUSION

Glomerular diameter is independently associated with an early change in UPCR after the initiation of treatment with dapagliflozin in patients with CKD.

Walking versus running and GFR trajectory in healthy young adults

BACKGROUND

The effect of physical activity on the primary prevention of chronic kidney disease (CKD) is unclear. We assessed walking and running as exercise behaviors and their associations with individual-level risk for kidney function decline.

METHODS

We conducted a historical cohort study in which we followed 20,976 young adults. Participants were interviewed periodically about their lifestyle, and clinical parameters were assessed. The decline in estimated glomerular filtration rate (eGFR) over time was divided into quartiles. Using logistic regressions, we estimated the odds ratio (OR) for being in the slowest declining quartile by consistency of running or walking. We also used Cox proportional hazards models to estimate the associations of physical activity with future eGFR < 90 ml/min/1.73m2. All models were adjusted for age, sex, smoking status, family history of kidney diseases, BMI, blood-pressure, baseline eGFR and serum cholesterol.

RESULTS

During 9.5 years of follow-up, the eGFR decreased by 0.97 ml/min/1.73m2 per year. Participants who reported in two consecutive questionnaires on walking as a leisure time activity had an OR of 1.21 (95% confidence interval: 1.03-1.41) to have slow eGFR decline compared to those who were physically inactive. Participants who predominantly reported on running as their physical activity were less likely to be slow eGFR decliners (OR:0.81, 95% CI:0.71-0.93). Similarly, consistent walking was associated with decreased risk for future eGFR < 90 ml/min/1.73m2 in contrast to consistent running which was associated with an increased risk for reduced eGFR. All associations showed dose dependent effects in terms of the number of weekly activity sessions.

CONCLUSIONS

Consistent walking, as opposed to consistent running, was associated with slower eGFR decline compared to inactive participants. These associations start already within the normal GFR range.

Sex-specific impact of polycyclic aromatic hydrocarbons and metals on renal function in U.S. adults: Mediating roles of inflammation, oxidative stress and aging

BACKGROUND

Previous research has established associations between polycyclic aromatic hydrocarbons (PAHs), heavy metals (HMs), and kidney damage. However, the impact of PAHs and HMs mixtures on chronic kidney disease (CKD), particularly gender differences, remains unclear.

METHODS

This study utilized data from the National Health and Nutrition Examination Survey (NHANES) data spanning 2003-2016 to investigate the association between PAHs and HMs with CKD, employing weighted logistic regression analyses. This exploration was complemented by gender-stratified restricted cubic spline (RCS) methods. Multiple mixture analysis models were applied to evaluate the combined effects of PAHs and HMs on kidney damage. Mediation analyses were conducted to explore the mediating effects of inflammation, oxidative stress, and aging biomarkers.

RESULTS

The results of the mixture analysis indicated a significant positive correlation between PAHs and HMs with the CKD risk in the general population, with cadmium (Cd), lead (Pb), and 2-naphthalene (2-NAP) contributing prominently to this relationship. These findings were consistent in the female subgroup. However, no effect of co-exposure to PAHs and HMs on CKD and urine albumin-to-creatinine ratio (UACR) was observed in the male subgroup. PAHs and HMs mixtures with CKD risk mediated by the biological age (BA) and phenotypic age (PA), with mediation proportions of 44.1 % and 61.4 %, respectively.

CONCLUSION

The study reveals a significant association between PAHs and HMs mixtures and CKD in the US population, with females being particularly susceptible. Biological aging emerges as a primary mediator in this relationship. Further prospective cohort studies are required to validate these findings.

Long-Term Functional and Structural Renoprotection After Experimental Acute Kidney Injury in Subclinical Chronic Kidney Disease In Vivo

Subclinical chronic kidney disease (sCKD) predisposes one to acute kidney injury (AKI) and chronic kidney disease (CKD). Reduced kidney functional reserve (KFR) detects sCKD in preclinical studies and predicts AKI after cardiac surgery. We evaluated renal protection in a rat model of kidney injury where ischaemia-reperfusion injury (IRI) was induced after sCKD. Dual treatment boosting nicotinamide adenine dinucleotide (NAD) by nicotinamide riboside (NR) combined with the mitochondria-targeted antioxidant SkQR1 protected the KFR and reduced structural kidney damage, including markers of vascular integrity and the relative blood volume (rBV). The dual treatment upregulated Sirt1 and Nrf2, increased the nuclear localisation of the mitochondrial biogenesis regulator PGC-1α and the mitochondrial protein marker COX4, and upregulated the antioxidant gene NOQ1. These observations suggest mitochondrial protection and modulation of the cellular redox state provided long-term structural and functional protection against kidney injury superimposed on background sCKD.

Renal hyperfiltration is associated with a reduced incidence of hypertension in individuals younger than 70

Although the connection between decreased kidney function and hypertension is commonly acknowledged, there is insufficient research examining the relationship between renal hyperfiltration (higher-than-normal estimated glomerular filtration rate (eGFR)) and the incidence risk of hypertension. Therefore, through a nationwide longitudinal study, our research aimed to explore the relationship between the eGFR and the incidence risk of hypertension in the general population. This research used the cohort records for the National Health Insurance Service in Korea, analyzing records from 1,873,550 individuals between the ages of 20 and 79 who underwent health check-ups between 2010 and 2011. The eGFR levels, determined by applying the 2009 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, were employed to evaluate the renal function. An incidence of hypertension was confirmed when a diagnosis of (primary or secondary) hypertension (International Classification of Diseases (ICD)-10 codes I10-I11) was noted at least once per year during outpatient or inpatient care with a prescription for antihypertensive medication or at least one more surpassing 140/90 mmHg from a health examination after the index date after excluding diagnosis of secondary hypertension. The mean age of subjects was 46.03 ± 11.24 years. The 411,029 (21.9%) hypertension cases were identified over a median follow-up of 9.53 years. In the multivariable Cox regression analysis, compared with the 5th decile, the 10th eGFR deciles (≥ 115.58 mL/min/1.73 m²) (hazard ratio (HR): 0.87, 95% confidence interval (CI)(0.85-0.88), p < 0.001) demonstrated a significant association with a reduced incidence of hypertension. Moreover, an eGFR exceeding 120 mL/min/1.73 m² was linked to a lowered likelihood of hypertension (HR: 0.78, 95% CI (0.76-0.80), p < 0.001) compared to normal eGFR levels (90 ~ 120 mL/min/1.73 m²). In contrast, in the subgroup analysis of ages over 70 years old, renal hyperfiltration was not associated with a reduced incidence of hypertension. In our study, renal hyperfiltration were associated with a reduced risk of hypertension, and this association was particularly significant in those younger than 70 years old. The association between renal hyperfiltration and a lower risk of hypertension incidence was likely to vary with age.

Association between daily coffee intake and diabetic kidney disease: evidence from the 2007 to 2016 NHANES

PURPOSE

Regular coffee intake is recognized as a protective factor against various chronic diseases, particularly diabetes. However, the correlation between coffee intake-both the act of drinking coffee and the amount consumed-and diabetic kidney disease (DKD) remains uncertain. The goal of this study is to measure the correlation between coffee intake and DKD.

METHODS

This cross-sectional study was based on data from the 2007 to 2016 National Health and Nutrition Examination Survey (NHANES). DKD was characterized by the coexistence of diabetes combined with impaired glomerular filtration rate (eGFR < 60 mL/min/1.73 m2) or ACR ≥ 30 mg/g. Weighted logistic regression and restricted cubic spline (RCS) analyses were adopted to evaluate the correlation between coffee intake and DKD. The subgroup analyses were implemented to assess the reliability of the results.

RESULTS

The study included 13,177 participants, representing a weighted population of 125,388,198 individuals. Among them, 8198 (64%) participants consumed coffee and 1430 (7.6%) were classified as having DKD. After controlling for covariates, multivariable logistic regression showed a negative correlation between moderate coffee intake and DKD (OR = 0.68; 95% CI: 0.55-0.83; P < 0.001). The RCS analysis suggested a U-shaped, non-linear correlation between coffee intake and DKD (P overall = 0.013; P nonlinear = 0.047). The subgroup analyses further supported the stability and reliability of these findings.

CONCLUSION

The results indicate a U-shaped correlation between coffee intake and diabetic kidney disease.

Overview of ADPKD in Pregnancy

Autosomal dominant polycystic kidney disease (ADPKD) is a systemic disorder that often affects patients in their third to fifth decades of life and is characterized by kidney cysts, chronic kidney disease (CKD), hypertension, and hepatic cysts. The development of clinical symptoms often coincides with childbearing years. Consequently, there are several considerations regarding pregnant patients with ADPKD. In this review, we detail the effects and management of ADPKD in the peripartum period and discuss family planning options, including assisted reproductive techniques (ART) and preimplantation genetic testing.

Upregulation of Piezo2 and increased extracellular matrix protein in diabetic kidney disease mice

Mechanical forces such as glomerular hyperfiltration are crucial in the pathogenesis and progression of diabetic kidney disease. Piezo2 is a mechanosensitive cation channel and plays a major role in various biological and pathophysiological phenomena. We previously reported Piezo2 expression in mouse and rat kidneys and its alteration by dehydration and hypertension. To elucidate the alteration of Piezo2 expression and its consequences in a mouse model of diabetic kidney disease, we used high salt-fed male KK-Ay mice, an accelerated genetic model of diabetic kidney disease. KK-Ay mice exhibited marked obesity, hyperglycemia, elevated blood pressure, higher creatinine clearance, and overt albuminuria. Histopathological analysis revealed glomerular hypertrophy, mesangial expansion, macrophage infiltration, tubular vacuolization, and interstitial fibrosis. The mRNA and protein expression analyses revealed (1) increased fibronectin protein expression in the glomerular areas, (2) upregulated Piezo2 expression in the glomerular mesangial cells and interstitial region, (3) increased Piezo2 and the fibronectin-coding gene Fn1 mRNA, and (4) a strong correlation of Piezo2 expression with that of Fn1 in the kidneys of diabetic kidney disease mice. Piezo2 upregulation and fibronectin accumulation were alleviated by an angiotensin II receptor blocker. In accordance with these in vivo results, in vitro study demonstrated that Piezo2 overexpression increased fibronectin production in HEK293T cells. In conclusion, we demonstrated that Piezo2 expression was upregulated in glomerular mesangial cells in a mouse model of diabetic kidney disease. Our results suggest that Piezo2 contributes to the progression of diabetic kidney disease by mediating glomerular fibronectin production, leading to glomerulosclerosis. Hyperfiltration is crucial in the pathogenesis of diabetic kidney disease. We showed that Piezo2 expression is upregulated in mesangial cells of diabetic kidney disease mice with glomerular fibronectin accumulation. Piezo2 overexpression increased fibronectin production in HEK293T cells. Piezo2 may contribute to diabetic kidney disease progression by mediating glomerular fibronectin production.

Influence of carnosine supplementation on disease progression in a rat model of focal segmental glomerulosclerosis

In diabetic kidney disease models, carnosine supplementation ameliorates renal pathology, but its influence in other renal pathologies is less explored. Thus, using the transgenic rat TGRNeph-hAT1 with sex-dependent focal segmental glomerulosclerosis, we first tested whether renal expression levels of carnosine system components correlate with disease. Next, we assessed whether carnosine supplementation in male rats improves pathology. In 10-wk-old phenotypically healthy male and female TGRNeph-hAT1 rats, we compared the renal expression of components of the carnosine system by qRT-PCR. Next, male TGRNeph-hAT1 rats were supplemented with carnosine in drinking water for 20 wk. Subsequently, urinary parameters, renal histology, and renal gene expression of renin-angiotensin system components were assessed. Male TGRNeph-hAT1 rats exhibited less renal expression of carnosine synthase 1, oligopeptide transporter 2, and taurine transporter and higher carnosinase 1 expression than female TGRNeph-hAT1 rats at a young age, before disease starts to develop. Male, but not female, TGRNeph-hAT1 rats developed severe albuminuria, glomerular hypertrophy, and focal and segmental glomerulosclerosis on aging. Carnosine supplementation ameliorated the glomerular hypertrophy but did not affect albuminuria, renal fibrosis, and podocyte loss. Moreover, carnosine significantly reduced renin and increased angiotensin-converting enzyme 2 expression within the kidney. Carnosine treatment alleviates glomerular hypertrophy in TGRNeph-hAT1 rats but does not improve other renal pathologies. Although amelioration of glomerular hypertrophy might be explained by changes in renal renin-angiotensin system expression, further studies are warranted to assess causality.NEW & NOTEWORTHY In diabetic kidney disease models, carnosine supplementation ameliorates renal pathology, but its influence in other renal pathologies is less explored. We tested whether renal expression levels of carnosine system components correlate with disease in the model of the transgenic rat TGRNeph-hAT1 with sex-dependent focal segmental glomerulosclerosis and whether carnosine supplementation in male rats improves pathology. Our results provide evidence that carnosine feeding affects the glomerular hypertrophy and renal RAS expression.

Cells of all trades - on the importance of spatial positioning of senescent cells in development, healing and aging

Biological processes are often spatially regulated, ensuring molecular and cellular events occur in their most strategically advantageous locations. Cellular senescence, marked by cell cycle arrest and hypersecretion, is recognized as an important part of physiological processes like development and healing, but it also contributes to aging and disease. However, the spatial distribution of senescent cells and its physiological and pathological impact remain unclear. Here we compile evidence on senescent cell localization in development, healing, and aging. We emphasize the significance of their spatial patterns and speculate on the effects of disrupted spatial positioning of senescence in relation to pathologies. To summarize the specific spatial functions of senescent cells, we propose to refer to them as 'barrier' and 'conductor' functions. The 'barrier' function of senescent cells, due to their altered morphology and apoptosis resistance, separates tissues and builds a border between two environments. The conductor function, with the secretion of signaling factors, influences the surrounding area and stimulates migration, differentiation, or proliferation, among other processes. Overall, this Review explores the spatial patterning of cellular senescence in biological processes, highlighting its dual roles as 'barrier' and 'conductor' functions, and examines the implications of senescent cell distribution in development, healing, aging, and disease.

Ultrasound Doppler renal pulsatility index is a predictive marker of arterial stiffness in children with solitary functioning kidney

INTRODUCTION

Patients with solitary functioning kidney (SFK) have glomerular hyperfiltration, hypertension, proteinuria and impaired renal function resulting in microvascular atherosclerotic abnormalities. This condition leads to an increase in arterial stiffness. In this study, we aimed to investigate the usefulness of non-invasive renal Doppler ultrasonography hemodynamic parameters in demonstrating arterial stiffness in pediatric patients with SFK.

METHODS

The study included 59 children aged 6-18 years who were diagnosed with SFK. Demographic, biochemical, anthropometric, and blood pressure data were recorded. The renal Doppler ultrasound hemodynamic parameters renal resistive index (RRI), renal pulsatility index (RPI), carotid-femoral pulse wave velocity (cfPWV), central augmentation index (cAIx) and carotid intima media thickness (cIMT) were evaluated.

RESULTS

Eighteen (30.5%) cases with acquired SFK and 41 (64.5%) cases with congenital SFK were detected. Central augmentation indices were higher in children with congenital SFK than in children with acquired SFK (p = 0.038). CkiD-eGFR-SCr-CysC was lower in patients with acquired SFK (p = 0.011). LDL cholesterol levels were higher in children with acquired SFK (p = 0.018). We found a significant correlation between RPI and cfPWV with a correlation coefficient (r) of 0.321 and a statistically significant p-value of 0.013.

CONCLUSIONS

Congenital SFK is associated with increased microvascular atherosclerotic burden. RPI assessment with renal Doppler ultrasound may be a non-invasive method to identify arterial stiffness.

Significantly higher rates of KIDINS220 polymorphisms in patients with obesity and end-stage renal disease

Background

Kinase D-interacting substrate of 220 kDa ("KIDINS220") is an integral plasma membrane protein essential to signaling throughout the body; abnormalities are linked to a variety of disorders, including obesity, but have never been directly linked to chronic- or end-stage renal disease.

Methods

Retrospective chart review identified patients with severe obesity who presented for pre-kidney transplant weight management. 20 individuals met criteria for testing for genetic causes of obesity. A χ2 test of independence was utilized to compare genetic mutation rates in this cohort to all individuals tested nationally.

Results

This case series presents a cohort of patients with severe obesity and end-stage renal disease who were subsequently found to have a significantly higher rate of KIDINS220 mutations (20 %, χ2 = 27.8, p < 0.0001) compared to the national positivity rate of all individuals tested for genetic causes of obesity.

Conclusions

Mutations within KIDINS220 may play a modulatory role in the progression of chronic kidney disease in patients with obesity, as evidenced by this small retrospective study. The relationship between KIDINS200, kidney disease, and obesity is complex and requires further study, but may represent a potential therapeutic target in the future.

Correlation Between Triglyceride-Glucose Index and Microvascular Complications in Patients With Early- Onset of Type 2 Diabetes Mellitus

OBJECTIVE

This study aimed to explore the potential correlation between the triglyceride-glucose (TyG) index and diabetic nephropathy (DN) and diabetic retinopathy (DR) in patients with early-onset type 2 diabetes mellitus (T2DM).

DESIGN

This cross-sectional study statistically analysed TyG index levels across DN and DR stages in patients with early-onset and non-early-onset T2DM.

PATIENTS

A total of 1530 T2DM patients were enrolled between January 2017 and August 2023 at Tianjin Fourth Central Hospital in Tianjin.

MEASUREMENTS

Correlation analysis and logistic regression were used to examine the association between the TyG index and microvascular complications. Kaplan-Meier plots and Cox regression analyses were employed to evaluate the effects of the TyG index on DN incidence. TyG index's diagnostic ability for DN was explored using the area under the receiver operating characteristic curve.

RESULTS

In patients with early-onset T2DM, the TyG index gradually decreased with DR aggravation and gradually increased with DN aggravation, showing a negative correlation with DR and a positive correlation with DN in patients with early-onset T2DM; logistic regression analysis suggested that the TyG index was an independent risk factor for DN (OR = 1.623, 95% CI = 1.175-2.242). The Cox regression analysis and Kaplan-Meier plots suggested that higher TyG was associated with an earlier incidence of DN in patients with early-onset T2DM.

CONCLUSION

In patients with early-onset T2DM, the TyG index could be used to evaluate the risk of microvascular complications, with elevated TyG levels potentially indicating high risk of insulin- resistance related renal injury.

Effect of Glomerular Hyperfiltration on Incident Cardiovascular Disease in Patients with Type 2 Diabetes Mellitus

Key Points

Patients with type 2 diabetes mellitus who had glomerular hyperfiltration (GHF) were younger and had fewer comorbid metabolic disorders, despite poor glycemic control. The relationship between eGFR and incident cardiovascular disease showed an inverted J-shaped pattern, which was highest among low filtration, followed by GHF. GHF was associated with a higher risk of cardiovascular disease, particularly myocardial infarction and heart failure.

Background

The effects of glomerular hyperfiltration (GHF) on cardiovascular disease (CVD) risk in patients with type 2 diabetes mellitus were explored.

Methods

This retrospective cohort study enrolled 1,952,053 patients with type 2 diabetes mellitus from the Korean National Health Insurance Service database between 2015 and 2016. On the basis of age- and sex-specific eGFR percentiles, patients were classified into five groups: <5 (low filtration), 5–40, 40–60, 60–95, and >95 (GHF). Patients with incident CVD (myocardial infarction [MI], stroke, and hospitalization for heart failure) were followed up until December 2022.

Results

CVD occurred in 214,111 patients (11%). The incidence rates were 36.1, 20.8, 18.3, 18.7, and 19.3 per 1000 person-years for the eGFR groups, respectively. Low filtration (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.53 to 1.59) and GHF (HR, 1.13; 95% CI, 1.10 to 1.15) were associated with higher CVD risk adjusted for covariates than that of the eGFR 40–60 percentile, showing an inverted J-shaped relationship. GHF was associated with a higher risk of MI (HR, 1.06; 95% CI, 1.01 to 1.11) and heart failure (HR, 1.17; 95% CI, 1.14 to 1.20) and with a higher risk of stroke. eGFR was associated with CVD risk across subgroups of age, sex, obesity, hypertension, and dyslipidemia. The effect of GHF on CVD may be greater in younger patients (HR=1.30, 1.17, and 1.05 in <40, 40–60, and ≥65 years old, respectively).

Conclusions

GHF was associated with CVD, particularly MI and heart failure. Screening for GHF in the early stages of type 2 diabetes mellitus may be beneficial.

Effect of dapagliflozin on renal haemodynamics in hyperfiltering T2D patients

AIMS

To investigate the effect of sodium-glucose co-transporter 2 inhibitor [SGLT-2i] therapy on renal haemodynamics in T2D patients with glomerular hyperfiltration.

MATERIALS AND METHODS

Sixty T2D patients with elevated [HYPER] and normal [NORMO] GFR were randomized to dapagliflozin 10 mg/day [DAPA/HYPER, n = 15; DAPA/NORMO, n = 15] or to metformin/glipizide [CONTROL/HYPER, n = 15; CONTROL/NORMO, n = 15] to reach similar glycaemic control after 4 months. GFR was measured with Iohexol and hyperfiltration was empirically defined as >125 mL/min/1.73 m2. GFR, renal plasma flow [RPF], mean arterial pressure [MAP], filtration fraction [FF], and renal vascular resistance [RVR] were determined before/after therapy.

RESULTS

HbA1c decreased similarly in all 4 groups. GFR declined by ~18% in DAPA/HYPER and by ~7% in DAPA/NORMO and did not change in CONTROLS (p < 0.05 vs. DAPA). RPF remained unchanged in all four groups. Thus, FF (%) declined from 0.23 ± 0.01 to 0.18 ± 0.01 in DAPA/HYPER and from 0.17 ± 0.01 to 0.15 ± 0.01 in DAPA/NORMO and remained unchanged in CONTROLS (p < 0.05 vs. DAPA). MAP (mmHg) decreased from 95.4 ± 1.4 to 88.1 ± 1.3 in DAPA/HYPER and from 95.6 ± 1.3 to 91.8 ± 0.8 in DAPA/NORMO and remained unchanged in CONTROLS (p < 0.05 vs. DAPA). RVR [mmHg/L/min] declined in DAPA/HYPER (92.7 ± 7.8 to 80.4 ± 6.1) and DAPA/NORMO (90.1 ± 3.0 to 81.4 ± 2.1) but not in CONTROLS (p < 0.05 vs. DAPA).

CONCLUSIONS

Despite comparable glycaemic control, dapagliflozin treatment, but not metformin and /or glipizide, reduced glomerular hyperfiltration in T2D patients and decreased both filtration fraction and renal vascular resistance. These findings suggest that a post-glomerular vasodilatory action of SGLT2 inhibitors contributes to their renal protective effect in T2D.

Relation of volatile organic compounds to renal function in American adolescents: three statistical models

This study was conducted to evaluate the relationship between 17 urinary metabolites of volatile organic compounds (mVOCs) in adolescents and renal function parameters (estimated glomerular filtration rate (eGFR), albumin-to-creatinine ratio (ACR), urinary albumin, serum uric acid (SUA), and blood urea nitrogen (BUN)). In adjusted generalised linear models (GLM), mVOCs were positively correlated with eGFR, urinary albumin, and BUN, and mVOCs were negatively correlated with ACR and SUA. Weighted Quartile Sum (WQS) index correlated with eGFR [β(95%CI): 0.040 (0.028, 0.052)], urine albumin [β(95%CI): 0.275 (0.203, 0.622)], SUA [β(95%CI): 0.040 (0.025, 0.055)] and BUN [β(95%CI): 0.102 (0.082, 0.122)]. In Bayesian Kernel Machine Regression (BKMR) model, total compound effect was positively correlated with eGFR, positive associations were observed in high concentration of the mixture with urine albumin and ACR. Findings suggest that single and mixed exposures to mVOCs may affect renal parameters in adolescents.

Chronic kidney disease

Chronic kidney disease (CKD) is defined by persistent abnormalities of kidney function or structure that have consequences for the health. A progressive decline of excretory kidney function has effects on body homeostasis. CKD is tightly associated with accelerated cardiovascular disease and severe infections, and with premature death. Kidney failure without access to kidney replacement therapy is fatal - a reality in many regions of the world. CKD can be the consequence of a single cause, but CKD in adults frequently relates rather to sequential injuries accumulating over the life course or to the presence of concomitant risk factors. The shared pathomechanism of CKD progression is the irreversible loss of kidney cells or nephrons together with haemodynamic and metabolic overload of the remaining nephrons, leading to further loss of kidney cells or nephrons. The management of patients with CKD focuses on early detection and on controlling all modifiable risk factors. This approach includes reducing the overload of the remaining nephrons with inhibitors of the renin-angiotensin system and the sodium-glucose transporter 2, as well as disease-specific drug interventions, if available. Hypertension, anaemia, metabolic acidosis and secondary hyperparathyroidism contribute to cardiovascular morbidity and reduced quality of life, and require diagnosis and treatment.

Association between visceral adipose tissue and glomerular hyperfiltration in adolescents: A cross-sectional study

OBJECTIVE

Glomerular hyperfiltration is an early indicator of obesity-related glomerular disease. However, in adolescents, there are no quantifiable indicators of obesity and glomerular hyperfiltration. This study investigates the association between visceral adipose tissue and glomerular hyperfiltration in adolescents.

METHODS

This cross-sectional study used data from the National Health and Nutrition Examination Survey (NHANES; 2011-2018), and adolescents aged 12-17 years were included. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) formed the independent variables while estimated glomerular filtration rate (eGFR) acted as the dependent variable. Their association was assessed using unadjusted and multivariate regression analyses, as well as subgroup and interaction analyses.

RESULTS

Multivariate regression analysis revealed that VAT was positively associated with eGFR and glomerular hyperfiltration among adolescents. The incidence of glomerular hyperfiltration increased by 99 % in boys and 56 % in girls per 100 g of VAT increase. Additionally, VAT and eGFR exhibited a linear relationship in both boys (β = 5.63, p < 0.001) and girls (β = 2.72, p < 0.001).

CONCLUSIONS

In US adolescents aged 12-17 years, VAT was positively correlated with eGFR and glomerular hyperfiltration.

Insightful Perspectives on Sodium-glucose Co-transporter 2 Inhibitors: Navigating Safety Updates and Beyond

SGLT2 (Sodium-Glucose Co-transporter 2) inhibitors, also known as gliflozin class, are a novel family of oral drugs being used to treat type 2 diabetes. SGLT2 inhibitors can work alone or in conjunction with other medications. This class includes five drugs, including canagliflozin, ertugliflozin, sotagliflozin, dapagliflozin, and empagliflozin. SGLT2 inhibitors inhibit the SGLT2 cotransporter in the proximal tubules of the kidney, reducing glucose and sodium reabsorption. It promotes the elimination of sugar in urine (diabetes mellitus) and lowers blood sugar levels. SGLT2 inhibitors also have pleiotropic effects on cardiac and renal function, broadening their therapeutic applications in heart failure. Despite the clinical benefits, regulators have placed secondary warnings in product information since the medications first hit the market. SGLT2 inhibitors, in particular, have had a significant impact on a variety of risk factors. This can lead to hypoglycaemia, urinary tract infections, diabetic ketoacidosis, lower limb amputation, and fractures. Although some of these events are uncommon, they can lead to severe and deadly consequences; therefore, patients must be closely monitored. In general, SLGT2 inhibitors are an efficient diabetes treatment with strong cardiovascular and renal protection and a favourable safety overview. This review sought to summarise the safety overview of commercially available SGLT2 inhibitors.

Challenges of Serum Creatinine Level in GFR Assessment and Drug Dosing Decisions in Kidney Injury

Serum creatinine (SCr) is widely regarded as a standard biomarker for assessing glomerular filtration rate (GFR) and is commonly used to guide dose adjustments for renally eliminated drugs. However, the application of SCr as a marker for evaluating GFR and drug dosing in kidney injury has significant limitations that are often overlooked in clinical practice. This oversight can result in subtherapeutic drug concentrations or adverse drug reactions due to inappropriate dosing adjustments based on SCr levels alone. This review aimed to highlight the factors affecting serum creatinine (SCr) and the challenges associated with using SCr as a biomarker for assessing GFR and adjusting drug doses with regard to its limitations and variability. The findings of this review underscore the complexity of SCr regulation, which is affected by its synthesis, metabolism, and excretion processes (glomerular filtration, tubular secretion, tubular reabsorption and extra-renal elimination), and disease states (such as trauma-induced hyperfiltration and HIV) and the use of medications (drug-creatinine interactions) lead to altered renal excretion of creatinine, either increasing or decreasing its levels. Additionally, the renal excretion pathways for drugs and creatinine are not entirely the same, making it difficult to use creatinine to evaluate drug renal excretion. In conclusion, SCr is an imperfect index of GFR and adjusting drug dosing, and the development of multi-biomarker panels, incorporating biomarkers from different excretory pathways-particularly those involving tubular transport-holds promise for improving the evaluation of renal excretory function and ensuring safer and more effective drug dosing.

Machine learning models predict the progression of long-term renal insufficiency in patients with renal cancer after radical nephrectomy

BACKGROUND

Chronic Kidney Disease (CKD) is a common severe complication after radical nephrectomy in patients with renal cancer. The timely and accurate prediction of the long-term progression of renal function post-surgery is crucial for early intervention and ultimately improving patient survival rates.

OBJECTIVE

This study aimed to establish a machine learning model to predict the likelihood of long-term renal dysfunction progression after surgery by analyzing patients' general information in depth.

METHODS

We retrospectively collected data of eligible patients from the Affiliated Hospital of Qingdao University. The primary outcome was upgrading of the Chronic Kidney Disease stage between pre- and 3-year post-surgery. We constructed seven different machine-learning models based on Logistic Regression (LR), Support Vector Machine (SVM), Random Forest (RF), Extreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (Lightgbm), Gaussian Naive Bayes (GaussianNB), and K-Nearest Neighbors (KNN). The performance of all predictive models was evaluated using the area under the receiver operating characteristic curve (AUC), precision-recall curves, confusion matrices, and calibration curves.

RESULTS

Among 360 patients with renal cancer who underwent radical nephrectomy included in this study, 185 (51.3%) experienced an upgrade in Chronic Kidney Disease stage 3-year post-surgery. Eleven predictive variables were selected for further construction of the machine learning models. The logistic regression model provided the most accurate prediction, with the highest AUC (0.8154) and an accuracy of 0.787.

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 systemic inflammatory response index is associated with chronic kidney disease in patients with hypertension: data from the national health and nutrition examination study 1999-2018

BACKGROUND

Studies have shown that in hypertensive patients, chronic kidney disease (CKD) is associated with a poor prognosis. Inflammation is a highly important factor in the progression of CKD. Detecting systemic inflammation and intervening promptly in patients with hypertension may help reduce the risk of CKD. The systemic inflammatory response index (SIRI) is a tool used to measure the systemic inflammatory response, but its relationship with CKD in patients with hypertension remains uncertain.

METHODS

We utilized data from the National Health and Nutrition Examination Survey (NHANES), which was conducted between 1999 and 2018. The analysis included a total of 20,243 participants, categorized into three groups based on SIRI tertiles. Logistic regression analysis and restricted cubic spline analysis were used to examine the relationship between the SIRI and CKD.

RESULTS

In patients with hypertension, there was a notable relationship between the SIRI and the odds of developing CKD. After full adjustment, there was a 31% greater likelihood of developing CKD associated with each incremental increase of 1 unit in the SIRI (OR: 1.31, 95% CI: 1.24-1.39, p < 0.001). The groups with greater SIRI values exhibited greater odds of developing CKD than did the T1 group (T2: OR: 1.20, 95% CI: 1.04-1.38, p = 0.015; T3: OR: 1.69, 95% CI: 1.47-1.94, p < 0.001).

CONCLUSION

A high SIRI is associated with an increased risk of CKD in hypertensive patients. The greater the SIRI is, the greater the risk of CKD in hypertensive patients.

Analyzing body composition in living kidney donors: impact on post-transplant kidney function

Living donor kidney transplantation boasts superior patient and graft survival rates compared to deceased donor kidney transplantation. However, the impact of living donor body composition (BC) on post-transplant kidney function remains uncertain. In a cohort of 293 living kidney donor-recipients pairs, we utilized linear mixed model analyses, adjusted for time and including a multiplicative interaction term of time with the donor body composition measure, and found no significant associations between any donor BC measure and the annual change in recipient post-transplantation estimated glomerular filtration rate (eGFR) [donor body mass index (BMI): B=-0.01, 95%CI -0.13; 0.11, p=0.88; donor waist circumference: B=0.02, 95%CI -0.02; 0.06, p=0.38; donor skeletal muscle index: B=-0.02, 95%CI -0.07; 0.04, p=0.63; donor skeletal muscle radiation attenuation: B=-0.002, 95%CI -0.06; 0.06, p=0.96; donor visceral adipose tissue index: B=-0.001, 95%CI -0.02; 0.02, p=0.93; donor subcutaneous adipose tissue index: B=-0.001, 95%CI -0.02; 0.02, p=0.94; donor intramuscular adipose tissue index: B=-0.12, 95%CI -0.29; 0.06, p=0.19; donor total abdominal adipose tissue index: B=-0.001, 95%CI -0.01; 0.01, p=0.89]. Our study suggests that pre-donation BC does not affect post-transplantation recipient eGFR in donor populations with a BMI below 35 kg/m2.

Hematological Response to Particle Debris Generated During Wear-Corrosion Processes of CoCr Surfaces Modified with Graphene Oxide and Hyaluronic Acid for Joint Prostheses

Various surface modifications to increase the lifespan of cobalt-chromium (CoCr) joint prostheses are being studied to reduce the wear rate in bone joint applications. One recently proposed modification involves depositing graphene oxide functionalized with hyaluronic acid (a compound present in joints) on CoCr surfaces, which can act as a solid lubricant. This paper analyzes the biological alterations caused by wear-corrosion phenomena that occur in joints, both from the perspective of the worn surface (in vitro model) and the particles generated during the wear processes (in vivo model). The analysis of the inflammatory response of macrophage was performed on CoCr surfaces modified with graphene oxide and functionalized with hyaluronic acid (CoCr-GO-HA), before and after wear-corrosion processes. The wear particles released during the wear-corrosion tests of the CoCr-GO-HA/CoCr ball pair immersed in 3 g/L hyaluronic acid were intra-articularly injected into the experimental animals. The hematological analysis in vivo was made considering a murine model of intra-articular injection into the left knee in male adult Wistar rats, at increasing concentrations of the collected wear particles dispersed in 0.9% NaCl. Non-significant differences in the inflammatory response to unworn CoCr-GO-HA surfaces and control (polystyrene) were obtained. The wear-corrosion of the CoCr-GO-HA disk increased the inflammatory response at both 72 and 96 h of material exposure compared to the unworn CoCr-GO-HA surfaces, although the differences were not statistically significant. The pro-inflammatory response of the macrophages was reduced on the worn surfaces of the CoCr modified and functionalized with graphene oxide (GO) and hyaluronic acid (HA), compared to the worn surfaces of the unmodified CoCr. The hematological analysis and tissue reactions after intra-articular injection did not reveal pathological damage, with average hematological values recorded, although slight reductions in creatinine and protein within non-pathological ranges were found. Some traces of biomaterial particles in the knee at the highest concentration of injected particles were only found but without inflammatory signs. The results show the potential benefits of using graphene in intra-articular prostheses, which could improve the quality of life for numerous patients.

Magnesium depletion score and depression: a positive correlation among US adults

Background

The Magnesium depletion score (MDS) serves as a novel metric for quantifying magnesium deficiency in the human body, comprehensively assessing four indicators: diuretic use, proton pump inhibitor use, estimated glomerular filtration rate, and alcohol abuse. However, there have been no studies examining the potential association between MDS and depression.

Methods

The study population for this cross-sectional study comprised adults from the National Health and Nutrition Examination Survey database from 2009 to 2018. Participants with a score of 10 or above on the Patient Health Questionnaire-9 were defined as having depression. We employed multivariable logistic regression models to investigate the association between MDS and depression. Furthermore, subgroup analyses were conducted to assess potential differences in this association among populations with diverse characteristics.

Results

A total of 13,197 participants were included in this study. After adjusting for all covariates, a significant positive correlation was observed between MDS and depression. Specifically, for every unit increase in MDS, the likelihood of developing depression increased by 13% (OR = 1.13, 95% CI: 1.04-1.22, p = 0.0025). This positive correlation was consistent across MDS groups, with a 19% increase in depression likelihood in the medium group (OR = 1.19, 95% CI: 1.01-1.41, p = 0.0404) and a 58% increase in the high group (OR = 1.58, 95% CI: 1.21-2.07, p = 0.0007), using the low subgroup as a reference. Subgroup analyses revealed significant differences in the relationship between MDS and depression across races, marital statuses, and hypertension status.

Conclusion

Our study has uncovered a significant positive association between MDS and depression. Reducing MDS in individuals may play a positive role in both the prevention and treatment of depression.

Obesity-related renal dysfunction: gender-specific influence of visceral adiposity and early impact of metabolic and bariatric surgery

Introduction

Renal dysfunction is a recognized complication of obesity with an incompletely characterized pathophysiology. Improvement of glomerular filtration rate (GFR) after metabolic and bariatric surgery (MBS) has been reported across all classes of renal function. Inter-gender differences with regard to correlates of renal function have been described, but the influence of body composition is an understudied area. We aimed to explore determinants of renal function in obesity and to assess its variations after MBS, with a focus on body composition parameters in males and females, respectively.

Materials methods

We conducted a retrospective study on 196 patients who underwent laparoscopic sleeve gastrectomy, evaluated preoperatively and 6 months after the intervention. Recorded data included clinical and biochemical assessment, as well as body composition estimation via dual-energy X-ray absorptiometry. Serum creatinine-based formulas were used for the estimation of GFR.

Results

We included a total of 196 patients (80 males and 116 females), with a mean age of 41.43 ± 10.79. Median baseline body mass index was 42.6 (6.61) kg/m2 and 6 months excess weight loss (EWL) reached 71.43 ± 17.18%, in females, estimated GFR correlated negatively with visceral adipose tissue (VAT) mass (rho=-.368) and this correlation was stronger in females with type 2 diabetes mellitus. Moreover, women in the third VAT mass tertile were 5 times more likely to have reduced GFR compared to the first tertile. Renal function improved after MBS across all classes of filtration. In males, this improvement correlated with EWL (rho=.358) and lean mass variation (rho=-.412), while in females it correlated with VAT mass variation (rho=-.266).

Conclusions

Our results are consistent with previous findings on the positive impact of MBS on renal function and suggest a more prominent impact of visceral adiposity on GFR in females.

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.

Association of Renal Hyperfiltration with Incidence of New-Onset Diabetes Mellitus: A Nationwide Cohort Study

Background and Objectives: While the connection between decreased kidney function and diabetes mellitus (DM) is commonly acknowledged, there is insufficient research examining the relationship between higher-than-normal estimated glomerular filtration rate (eGFR) and the incidence risk of new-onset DM. Our research aimed to explore the relationship between an eGFR and the incidence risk of new-onset DM in the Korean general population through a nationwide longitudinal study. Methods: This research employed the cohort records of the National Health Insurance Service in Korea, analyzing records from 2,294,358 individuals between the ages of 20 and 79 who underwent health check-ups between 2010 and 2011. The eGFR levels from the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation were used to assess the renal function. New-onset DM was defined as two or more claims with the International Classification of Diseases-10 classification codes E10 to E14, being prescribed any medication for lowering blood glucose, or having a record of fasting plasma glucose levels of ≥126 mg/dL from a health examination after the index date. Results: The mean age of subjects was 47.34 ± 13.76 years. The 150,813 (6.57%) new-onset DM cases were identified over a median follow-up of 9.63 years. In the multivariable Cox regression analysis, in comparison with the 5th decile, the 10th (≥114.12 mL/min/1.73 m2) (hazard ratio (HR): 0.52, 95% confidence interval (CI) (0.50-0.54), p < 0.001) eGFR decile was significantly associated with a decreased incidence of new-onset DM. Moreover, eGFR >120 mL/min/1.73 m2 was associated with a reduced risk of new-onset DM (HR: 0.40, 95% CI (0.39-0.42), p < 0.001). These results were consistent regardless of the presence of impaired glucose tolerance, age, or obesity. Conclusion: Our study showed higher-than-normal eGFR levels were associated with a lower risk of incidence for new-onset DM regardless of the presence of impaired glucose tolerance, age, or obesity. In general population, higher-than-normal eGFR may be associated with a lower risk of incidence of new-onset DM.

Associations between urinary rare Earth elements with renal function: Findings from a cross-sectional study in Guangxi, China

BACKGROUND

With increased applications of rare earth elements (REEs) across various industries, evaluating the relationship between REEs exposure and potential health effects has become a public concern. In vivo experiments have established that REEs impact renal function. However, relevant epidemiological evidence on this relationship remains scarce. The objective of this study is to examine the impact of exposure to REEs on renal function.

METHODS

In this cross-sectional study, 1052 participants were recruited from Guangxi, China. We measured urinary concentrations of 12 REEs using an inductively coupled plasma-mass spectrometer (ICP-MS). Multiple linear regression models were developed to explore the relationship between a single REEs exposure and the estimated glomerular filtration rate (eGFR), a marker of renal function. Weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to examine the combined effects of REE co-exposure on eGFR.

RESULTS

In the multiple linear regression analysis, increasing the concentrations of lanthanum (La, β: 8.22, 95% CI: 5.67-10.77), cerium (Ce, β:6.61, 95% CI: 3.80-9.43), praseodymium (Pr, β: 8.46, 95% CI: 5.85-11.07), neodymium (Nd, β:8.75, 95% CI: 6.10-11.41), and dysprosium (Dy, β:7.38, 95% CI: 4.85-9.91) significantly increased the eGFR. In the WQS regression model, the WQS index was significantly associated with eGFR (β: 4.03, 95% CI: 2.46-5.60), with Pr having the strongest correlation with eGFR. Similar results were obtained in the BKMR model. Additionally, interactions between Pr and La, and Pr and Nd were observed.

CONCLUSIONS

Co-exposure to REEs is positively associated with elevated eGFR. Pr is likely to have the most significant influence on increased eGFRs and this might be exacerbated when interacting with La and Nd. Mixed exposure to low doses of REEs had a protective effect on renal function, which can provide some evidence for the exposure threshold of REEs in the environment.

TRIAL REGISTRATION

The study has been approved by the Guangxi Medical University Medical Ethics Committee (#20170206-1), and all participants provided written informed consent.

Combined UPLC-QqQ-MS/MS and AP-MALDI Mass Spectrometry Imaging Method for Phospholipidomics in Obese Mouse Kidneys: Alleviation by Feeding Sea Cucumber Phospholipids

Sea cucumber phospholipids have ameliorative effects on various diseases related to lipid metabolism. However, it is unclear whether it can ameliorate obesity-associated glomerulopathy (ORG) induced by a high-fat diet (HFD). The present study applied UPLC-QqQ-MS/MS and atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry imaging (AP-MALDI MSI) to investigate the effects of sea cucumber phospholipids, including plasmalogen PlsEtn and plasmanylcholine PakCho, on phospholipid profiles in the HFD-induced ORG mouse kidney. Quantitative analysis of 135 phospholipids revealed that PlsEtn and PakCho significantly modulated phospholipid levels. Notably, PlsEtn modulated kidney overall phospholipids better than PakCho. Imaging the "space-content" of 9 phospholipids indicated that HFD significantly increased phospholipid content within the renal cortex. Furthermore, PlsEtn and PakCho significantly decreased the expression of transport-related proteins CD36, while elevating the expression of fatty acid β-oxidation-related protein PPAR-α in the renal cortex. In conclusion, sea cucumber phospholipids reduced renal lipid accumulation, ameliorated renal damage, effectively regulated the content and distribution of renal phospholipids, and improved phospholipid homeostasis, exerting an anti-OGR effect.

Machine Learning for Predicting Chronic Renal Disease Progression in COVID-19 Patients with Acute Renal Injury: A Feasibility Study

This study aimed to determine the feasibility of applying machine-learning methods to assess the progression of chronic kidney disease (CKD) in patients with coronavirus disease (COVID-19) and acute renal injury (AKI). The study was conducted on patients aged 18 years or older who were diagnosed with COVID-19 and AKI between April 2020 and March 2021, and admitted to a second-level hospital in Mérida, Yucatán, México. Of the admitted patients, 47.92% died and 52.06% were discharged. Among the discharged patients, 176 developed AKI during hospitalization, and 131 agreed to participate in the study. The study's results indicated that the area under the receiver operating characteristic curve (AUC-ROC) for the four models was 0.826 for the support vector machine (SVM), 0.828 for the random forest, 0.840 for the logistic regression, and 0.841 for the boosting model. Variable selection methods were utilized to enhance the performance of the classifier, with the SVM model demonstrating the best overall performance, achieving a classification rate of 99.8% ± 0.1 in the training set and 98.43% ± 1.79 in the validation set in AUC-ROC values. These findings have the potential to aid in the early detection and management of CKD, a complication of AKI resulting from COVID-19. Further research is required to confirm these results.

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.

Pediatric Bilateral Hypoplastic Kidney Complicated With C1q Nephropathy: A Case Report

Progressive kidney dysfunction is often observed in children with bilateral hypoplastic kidneys. While glomerulopathy can exacerbate hypoplastic kidney progression, only IgA nephropathy and post-streptococcal acute glomerulonephritis have been noted in such cases. Herein, we present a case of a four-year-old female patient with bilateral hypoplastic kidney, kidney dysfunction, and significant proteinuria (urinary protein/creatinine ratio > 1 g/gCr), prompting referral owing to persistent hematuria since two years of age. Enalapril was initiated; however, urinary findings exhibited no improvement despite stable symptoms and kidney function. Subsequently, a kidney biopsy was performed at six years of age, and C1q nephropathy was diagnosed. Given the presence of only mild mesangial proliferation, steroids were not administered; enalapril treatment was continued. By seven years of age, the patient's hematuria had resolved, and proteinuria levels had decreased. On the latest follow-up at 12 years of age, kidney function was preserved with only mild proteinuria. This case report highlights the favorable prognosis of asymptomatic C1q nephropathy characterized by mild mesangial proliferation, even in patients with hypoplastic kidneys, renal dysfunction, and significant proteinuria. It emphasizes the significance of timely pathological evaluation for guiding appropriate interventions in such patients.

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.