Glomerular hemodynamics in severe obesity

Vancomycin population pharmacokinetics and dosing proposal for the initial treatment in obese adult patients

Aim

The aim of this study was to develop a vancomycin population pharmacokinetic model in adult obese patients and propose covariate-based dosing individualization in order to maximize the achievement of the newly recommended PK/PD target, according to a revised consensus guideline from 2020.

Methods

Therapeutic drug monitoring data from initial vancomycin therapy (first 3 days of treatment) in adult obese (BMI ≥ 30 kg/m2) patients from 2013 to 2022 were analyzed using a non-linear mixed-effects modeling method, and Monte Carlo simulations were then used to find the optimal dosage maximizing the PK/PD target attainment.

Results

A total of 147 vancomycin serum levels obtained from 138 patients were included in the analysis. Based on the covariate model diagnosis among all tested variables, no reliable predictor of vancomycin volume of distribution (Vd) was identified, while clearance (CL) was positively correlated with eGFR and lean body mass. Creatinine-based eGFR predicted vancomycin CL better than cystatin C-based eGFR. The median (interquartile range) value from conditional modes of individual estimates of Vd, CL, and elimination half-life in our population was 74.0 (70.5-75.4) L, 6.65 (4.95-8.42) L/h, and 7.7 (6.0-10.0) h, respectively.

Conclusion

We proposed dosing individualization based on the covariate found in order to maximize the achievement of the newly recommended PK/PD target of the AUC/MIC ratio of 400-600. Clinical pharmacy/pharmacology interventions may lead to an improvement in vancomycin dosing with a reflection in PK/PD target attainment.

Direct Oral Anticoagulants: Navigating Through Clinical Challenges

PURPOSE

Direct oral anticoagulants (DOACs) have been approved, for over a decade, by both European and American medicine agencies, for treatment and prevention of several cardiovascular conditions. Since then, an increasing amount of data has been added to the medical literature day by day, resulting in a dichotomy in selection of the appropriate agent, dosage, and duration of treatment for special populations with multiple comorbidities. Considering these issues, we have prepared a comprehensive review for the clinical practitioner, to optimize the DOAC utilization in clinical practice.

METHODS

A thorough literature search and review was conducted, concerning mainly the last decade. Our review focused on the current guidelines and the most recently published studies in PubMed, Science Direct Scopus, and Google Scholar to date.

CONCLUSION

The purpose of this study is to provide guidance for healthcare professionals for making proper decisions when confronted with clinical challenges. Nevertheless, further research is required to establish DOAC superiority in complicated cases, where there is clinical uncertainty.

The 10-Year Effects of Intensive Lifestyle Intervention on Kidney Outcomes

Rationale & Objective

Limited data exist on longitudinal kidney outcomes after nonsurgical obesity treatments. We investigated the effects of intensive lifestyle intervention on kidney function over 10 years.

Study Design

Post hoc analysis of Action for Health in Diabetes (Look AHEAD) randomized controlled trial.

Setting & Participants

We studied 4,901 individuals with type 2 diabetes and body mass index of ≥25 kg/m2 enrolled in Look AHEAD (2001-2015). The original Look AHEAD trial excluded individuals with 4+ urine dipstick protein, serum creatinine level of >1.4 mg/dL (women), 1.5 mg/dL (men), or dialysis dependence.

Exposures

Intensive lifestyle intervention versus diabetes support and education (ie, usual care).

Outcome

Primary outcome was estimated glomerular filtration rate (eGFR, mL/min/1.73 m2) slope. Secondary outcomes were mean eGFR, slope, and mean urine albumin to creatinine ratio (UACR, mg/mg).

Analytical Approach

Linear mixed-effects models with random slopes and intercepts to evaluate the association between randomization arms and within-individual repeated measures of eGFR and UACR. We tested for effect modification by baseline eGFR.

Results

At baseline, mean eGFR was 89, and 83% had a normal UACR. Over 10 years, there was no difference in eGFR slope (+0.064 per year; 95% CI: -0.036 to 0.16; P = 0.21) between arms. Slope or mean UACR did not differ between arms. Baseline eGFR, categorized as eGFR of <80, 80-100, or >100, did not modify the intervention's effect on eGFR slope or mean.

Limitations

Loss of muscle may confound creatinine-based eGFR.

Conclusions

In patients with type 2 diabetes and preserved kidney function, intensive lifestyle intervention did not change eGFR slope over 10 years. Among participants with baseline eGFR <80, lifestyle intervention had a slightly higher longitudinal mean eGFR than usual care. Further studies evaluating the effects of intensive lifestyle intervention in people with kidney disease are needed.

MAFLD and glomerular hyperfiltration in subjects with normoglycemia, prediabetes and type 2 diabetes: A cross-sectional population study

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD, 2020 diagnostic criteria) and glomerular hyperfiltration share common risk factors, including obesity, insulin resistance, impaired glucose tolerance, diabetes, dyslipidemia, and hypertension.

AIMS

To assess the prevalence of MAFLD and its association with glomerular hyperfiltration and age-related worsening of kidney function in subjects with normoglycemia, prediabetes and type 2 diabetes mellitus (T2DM).

METHODS

We analysed data recorded during occupational health visits of 125,070 Spanish civil servants aged 18-65 years with a de-indexed glomerular filtration rate (GFR) estimated with the chronic-kidney-disease-epidemiological (CKD-EPI) equation (estimated glomerular filtration rate [eGFR]) ≥60 mL/min. Subjects were categorised according to fasting plasma glucose levels <100 mg/dL (normoglycemia), ≥100 and ≤ 125 mg/dL (prediabetes), or ≥126 mg/dL and/or antidiabetic treatment (T2DM). The association between MAFLD and glomerular hyperfiltration, defined as a de-indexed eGFR above the age- and gender-specific 95th percentile, was assessed by multivariable logistic regression.

RESULTS

In the whole study group, MAFLD prevalence averaged 19.3%. The prevalence progressively increased from 14.7% to 33.2% and to 48.9% in subjects with normoglycemia, prediabetes and T2DM, respectively (p < 0.001 for trend). Adjusted odds ratio (95% CI) for the association between MAFLD and hyperfiltration was 9.06 (8.53-9.62) in the study group considered as a whole, and 8.60 (8.03-9.21), 9.52 (8.11-11.18) and 8.31 (6.70-10.30) in subjects with normoglycemia, prediabetes and T2DM considered separately. In stratified analyses, MAFLD amplified age-dependent eGFR decline in all groups (p < 0.001).

CONCLUSIONS

MAFLD prevalence increases across the glycaemic spectrum. MAFLD is significantly associated with hyperfiltration and amplifies the age-related eGFR decline.

Obesity aggravates acute kidney injury resulting from ischemia and reperfusion in mice

In critically ill patients, overweight and obesity are associated with acute respiratory distress syndrome and acute kidney injury (AKI). However, the effect of obesity on ischemia-reperfusion injury (IRI)-induced AKI is unknown. We hypothesized that obesity would aggravate renal IRI in mice. We fed mice a standard or high-fat diet for eight weeks. The mice were divided into four groups and submitted to sham surgery or IRI: obese, normal, normal + IRI, obese, and obese + IRI. All studies were performed 48 h after the procedures. Serum glucose, cholesterol, and creatinine clearance did not differ among the groups. Survival and urinary osmolality were lower in the obese + IRI group than in the normal + IRI group, whereas urinary neutrophil gelatinase-associated lipocalin levels, tubular injury scores, and caspase 3 expression were higher. Proliferating cell nuclear antigen expression was highest in the obese + IRI group, as were the levels of oxidative stress (urinary levels of thiobarbituric acid-reactive substances and renal heme oxygenase-1 protein expression), whereas renal Klotho protein expression was lowest in that group. Expression of glutathione peroxidase 4 and peroxiredoxin 6, proteins that induce lipid peroxidation, a hallmark of ferroptosis, was lower in the obese + IRI group. Notably, among the mice not induced to AKI, macrophage infiltration was greater in the obese group. In conclusion, greater oxidative stress and ferroptosis might aggravate IRI in obese individuals, and Klotho could be a therapeutic target in those with AKI.

Obesity is associated with acute kidney injury in ST-segment-elevation myocardial infarction undergoing percutaneous coronary intervention: A national representative cohort study

BACKGROUND

Acute kidney injury (AKI) is a frequent and potentially life-threatening complication after percutaneous coronary intervention (PCI) in patients with ST-segment-elevation myocardial infarction (STEMI). However, the relationship between obesity and the risk of AKI in this specific patient population has not been previously examined.

METHODS

We queried the National Inpatient Sample (2016-2019) using ICD-10 codes to obtain a sample of adults with STEMI undergoing PCI. All patients were further subcategorized into obese and nonobese cohorts. The primary outcome was the incidence of AKI. Multivariate regression analysis was performed to assess the impact of obesity on AKI. The consistency of this correlation between subgroups was investigated using subgroup analysis and interaction testing.

RESULTS

A total of 62,599 (weighted national estimate of 529,016) patients were identified, of which 9.80% (n = 6137) had AKI. Obesity comprised 19.78% (n = 1214) of the AKI cohort. Obese patients were on average younger, male, white, and had more comorbidities. Additionally, there was a significant positive association between obesity and AKI incidence (adjusted odds ratio [aOR]: 1.24, 95% confidence interval [CI]: 1.15-1.34), which was more pronounced in female patients (aOR: 1.56, 95% CI: 1.33-1.82, p < 0.001, p-interaction = 0.008). The AKI incidence in these patients increased steadily during the 4-year study period, and it was consistently higher in obese patients than in nonobese patients (p-trend < 0.001 for all).

CONCLUSIONS

Obesity was independently associated with a greater risk of AKI among adults with STEMI undergoing PCI, particularly in female patients.

Measurement of Glomerular Filtration Rate in Patients Undergoing Renal Surgery for Cancer: Estimated Glomerular Filtration Rate versus Measured Glomerular Filtration Rate in the Era of Precision Medicine

BACKGROUND

In the era of precision medicine, determining reliable renal function assessment remains a critical and debatable issue, especially in nephrology and oncology.

SUMMARY

This paper delves into the significance of accurately measured glomerular filtration rate (mGFR) in clinical practice, highlighting its essential role in guiding medical decisions and managing kidney health, particularly in the context of renal cancer (RC) patients undergoing nephrotoxic anti-cancer drugs. The limitations and advantages of traditional glomerular filtration rate (GFR) estimation methods, primarily using serum biomarkers like creatinine and cystatin C, are discussed, emphasizing their possible inadequacy in cancer patients. Specifically, newer formulae designed for GFR estimation in cancer patients may not perform at best in RC patients. The paper explores various methods for direct GFR measurement, including the gold standard inulin clearance and alternatives like iohexol plasma clearance.

KEY MESSAGE

Despite the logistical challenges of these methods, their implementation is crucial for accurate renal function assessment. The paper concludes by emphasizing the need for continued research and innovation in GFR measurement methodologies to improve patient outcomes, particularly in populations with complex medical needs.

Obesity-related glomerulopathy is associated with elevated WT1 expression in podocytes

BACKGROUND

The prevalence of obesity is increasing worldwide at an alarming rate. In addition to the increased incidence of cardiovascular and metabolic diseases, obesity is the most potent risk factor for developing chronic kidney disease (CKD). Although systemic events such as hemodynamic factors, metabolic effects, and lipotoxicity were implicated in the pathophysiology of obesity-related glomerulopathy (ORG) and kidney dysfunction, the precise mechanisms underlying the association between obesity and CKD remain unexplored.

METHODS

In this study, we employed spontaneous WNIN/Ob rats to investigate the molecular events that promote ORG. Further, we fed a high-fat diet to mice and analyzed the incidence of ORG. Kidney functional parameters, micro-anatomical manifestations, and podocyte morphology were investigated in both experimental animal models. Gene expression analysis in the rodents was compared with human subjects by data mining using Nephroseq and Kidney Precision Medicine Project database.

RESULTS

WNIN/Ob rats were presented with proteinuria and several glomerular deformities, such as adaptive glomerulosclerosis, decreased expression of podocyte-specific markers, and effacement of podocyte foot process. Similarly, high-fat-fed mice also showed glomerular injury and proteinuria. Both experimental animal models showed increased expression of podocyte-specific transcription factor WT1. The altered expression of putative targets of WT1 such as E-cadherin, podocin (reduced), and α-SMA (increased) suggests elevated expression of WT1 in podocytes elicits mesenchymal phenotype. Curated data from CKD patients revealed increased expression of WT1 in the podocytes and its precursors, parietal epithelial cells.

CONCLUSION

WT1 is crucial during nephron development and has minimal expression in adult podocytes. Our study discovered elevated expression of WT1 in podocytes in obesity settings. Our analysis suggests a novel function for WT1 in the pathogenesis of ORG; however, the precise mechanism of WT1 induction and its involvement in podocyte pathobiology needs further investigation.

Being precise with anticoagulation to reduce adverse drug reactions: are we there yet?

Anticoagulants are potent therapeutics widely used in medical and surgical settings, and the amount spent on anticoagulation is rising. Although warfarin remains a widely prescribed oral anticoagulant, prescriptions of direct oral anticoagulants (DOACs) have increased rapidly. Heparin-based parenteral anticoagulants include both unfractionated and low molecular weight heparins (LMWHs). In clinical practice, anticoagulants are generally well tolerated, although interindividual variability in response is apparent. This variability in anticoagulant response can lead to serious incident thrombosis, haemorrhage and off-target adverse reactions such as heparin-induced thrombocytopaenia (HIT). This review seeks to highlight the genetic, environmental and clinical factors associated with variability in anticoagulant response, and review the current evidence base for tailoring the drug, dose, and/or monitoring decisions to identified patient subgroups to improve anticoagulant safety. Areas that would benefit from further research are also identified. Validated variants in VKORC1, CYP2C9 and CYP4F2 constitute biomarkers for differential warfarin response and genotype-informed warfarin dosing has been shown to reduce adverse clinical events. Polymorphisms in CES1 appear relevant to dabigatran exposure but the genetic studies focusing on clinical outcomes such as bleeding are sparse. The influence of body weight on LMWH response merits further attention, as does the relationship between anti-Xa levels and clinical outcomes. Ultimately, safe and effective anticoagulation requires both a deeper parsing of factors contributing to variable response, and further prospective studies to determine optimal therapeutic strategies in identified higher risk subgroups.

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.

Anti-obesity pharmacotherapy in adults with chronic kidney disease

Obesity is a leading risk factor for the development and progression of kidney disease and a major barrier to optimal management of patients with chronic kidney disease. While in the past anti-obesity drugs offered only modest weight loss efficacy in exchange for various safety and tolerability risks, a wave of safer, more tolerable, and more effective treatment options is transforming the management of obesity. This review evaluates current and future pharmacologic anti-obesity therapy in adults through a kidney-oriented lens. It also explores the goals of anti-obesity treatment, describes the underlying putative mechanisms of action, and raises important scientific questions that deserve further exploration in people with chronic kidney disease.

Impact of body mass index on adverse kidney events in diabetes mellitus patients: A systematic-review and meta-analysis

BACKGROUND

The incidence of chronic kidney disease among patients with diabetes mellitus (DM) remains a global concern. Long-term obesity is known to possibly influence the development of type 2 diabetes mellitus. However, no previous meta-analysis has assessed the effects of body mass index (BMI) on adverse kidney events in patients with DM.

AIM

To determine the impact of BMI on adverse kidney events in patients with DM.

METHODS

A systematic literature search was performed on the PubMed, ISI Web of Science, Scopus, Ovid, Google Scholar, EMBASE, and BMJ databases. We included trials with the following characteristics: (1) Type of study: Prospective, retrospective, randomized, and non-randomized in design; (2) participants: Restricted to patients with DM aged ≥ 18 years; (3) intervention: No intervention; and (4) kidney adverse events: Onset of diabetic kidney disease [estimated glomerular filtration rate (eGFR) of < 60 mL/min/1.73 m2 and/or microalbuminuria value of ≥ 30 mg/g Cr], serum creatinine increase of more than double the baseline or end-stage renal disease (eGFR < 15 mL/min/1.73 m2 or dialysis), or death.

RESULTS

Overall, 11 studies involving 801 patients with DM were included. High BMI (≥ 25 kg/m2) was significantly associated with higher blood pressure (BP) [systolic BP by 0.20, 95% confidence interval (CI): 0.15-0.25, P < 0.00001; diastolic BP by 0.21 mmHg, 95%CI: 0.04-0.37, P = 0.010], serum albumin, triglycerides [standard mean difference (SMD) = 0.35, 95%CI: 0.29-0.41, P < 0.00001], low-density lipoprotein (SMD = 0.12, 95%CI: 0.04-0.20, P = 0.030), and lower high-density lipoprotein (SMD = -0.36, 95%CI: -0.51 to -0.21, P < 0.00001) in patients with DM compared with those with low BMIs (< 25 kg/m2). Our analysis showed that high BMI was associated with a higher risk ratio of adverse kidney events than low BMI (RR: 1.22, 95%CI: 1.01-1.43, P = 0.036).

CONCLUSION

The present analysis suggested that high BMI was a risk factor for adverse kidney events in patients with DM.

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.

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.

Obesity, Hyperfiltration, and Early Kidney Damage: A New Formula for the Estimation of Creatinine Clearance

CONTEXT

Glomerular hyperfiltration may represent a direct pathogenetic link between obesity and kidney disease. The most widely used methods to estimate creatine clearance such as Cockroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) have not been validated in subjects with obesity.

OBJECTIVE

The performance of prediction formulas was compared with measured creatinine clearance (mCrCl) in subjects with obesity.

METHODS

The study population included 342 patients with obesity (mean BMI 47.6 kg/m2) without primary kidney disease. A urine collection was performed over 24 hours for measurement of CrCl.

RESULTS

mCrCl increased with body weight. The CG formula showed an overestimation at high CrCl, whereas an underestimation resulted from CKD-EPI and MDRD. To improve the accuracy of estimated CrCl (eCrCl), a new CG-based formula was developed:53+0.7×(140-Age)×Weight/(96xSCr)×(0.85iffemale)A cut-off point for BMI of 32 kg/m2 was identified, at which the new formula may be applied to improve eCrCl.

CONCLUSION

In patients with obesity the glomerular filtration rate increases with body weight, and it is associated with the presence of albuminuria, suggesting an early kidney injury. We propose a novel formula that improves the accuracy of eCrCl to avoid missed diagnoses of hyperfiltration in patients with obesity.

Physiological confounders of renal blood flow measurement

OBJECTIVES

Renal blood flow (RBF) is controlled by a number of physiological factors that can contribute to the variability of its measurement. The purpose of this review is to assess the changes in RBF in response to a wide range of physiological confounders and derive practical recommendations on patient preparation and interpretation of RBF measurements with MRI.

METHODS

A comprehensive search was conducted to include articles reporting on physiological variations of renal perfusion, blood and/or plasma flow in healthy humans.

RESULTS

A total of 24 potential confounders were identified from the literature search and categorized into non-modifiable and modifiable factors. The non-modifiable factors include variables related to the demographics of a population (e.g. age, sex, and race) which cannot be manipulated but should be considered when interpreting RBF values between subjects. The modifiable factors include different activities (e.g. food/fluid intake, exercise training and medication use) that can be standardized in the study design. For each of the modifiable factors, evidence-based recommendations are provided to control for them in an RBF-measurement.

CONCLUSION

Future studies aiming to measure RBF are encouraged to follow a rigorous study design, that takes into account these recommendations for controlling the factors that can influence RBF results.

Non-albumin proteinuria marks tubular involvement and is associated with arterial stiffness in subjects affected by severe obesity

INTRODUCTION

Obesity is a well-established risk factor for kidney disease, and tubular damage can play a pivotal role in the development of obesity-related kidney damage. This study aimed to investigate the pathophysiological pathways involved in the development of non-albumin proteinuria (NAP), a marker of tubular involvement, in a cohort of subjects with severe obesity and preserved kidney function.

METHODS

A total of 106 subjects with BMI ≥ 35 kg/m2 in waiting list for bariatric surgery underwent blood chemistry analysis including metabolic and lipid profile, vascular tests for cardiovascular risk stratification and a comprehensive assessment of kidney function, including renal resistive index (RRI) and NAP measurement.

RESULTS

Nineteen patients with ACR ≥ 30 mg/g regardless of NAP values (ALB+), nineteen with NAP≥ 150 mg/g and albuminuria < 30 mg/g (iNAP) and sixty-eight without proteinuria (No-P) were found. Both ALB+ and iNAP groups exhibited a higher prevalence of hypertension and anti-hypertensive treatment compared to No-P, while the prevalence of diabetes was similar between groups. Concerning lipid profile, no differences in total, HDL and LDL cholesterol were found, while ALB+ patients had higher serum triglyceride levels than the other two groups. RRI and carotid-femoral pulse wave velocity (cf-PWV) was significantly higher in ALB+ and iNAP groups compared to No-P. Remarkably, cf-PWV remained still significant after adjustment for age, sex and MBP (p = 0.0004). In overall population, a multiple regression analysis showed that cf-PWV was an independent determinant of NAP in a model including age, sex, glycated hemoglobin, systolic and mean blood pressure (R2 =0.17, p = 0.031).

CONCLUSION

iNAP subjects showed increased arterial stiffness comparable to that observed in ALB+ group, suggesting that they may represent a subgroup at higher cardiovascular risk, often unrecognized in clinical practice.

Glomerular Hyperfiltration: A Marker of Fibrosis Severity in Metabolic Associated Steatotic Liver Disease in an Adult Population

Glomerular hyperfiltration (GH) is an increase in the glomerular filtration rate, possibly progressing to chronic kidney disease (CKD). Metabolic-associated steatotic liver disease (MASLD) is linked to an increased risk of CKD, especially if fibrosis is present; however, the association between GH and MASLD has not been explored. To evaluate GH prevalence in MASLD and its possible correlation with liver fibrosis. 772 consecutive patients with ultrasound MASLD (mean age 47.3 ± 8.9 years, 67.1% males) were enrolled. GH was defined as estimated glomerular filtration rate (eGFR) greater than the upper quartile of values in the cohort. Liver stiffness measurement (LSM) by FibroScan ≥ 7.2 kPa suggested liver fibrosis. GH was present in 20% of patients, liver fibrosis in 30%. In total, 53.4% of the cohort was obese, 40.9% hypertensive, 36.3% diabetic and 70.8% dyslipidaemic. GH patients compared to non-GH were significantly younger (38.4 ± 8.3 vs. 49.5 ± 7.7, p < 0.001), with higher prevalence of LSM > 7.2 kPa (35.5% vs. 29%, p < 0.001), without any difference in metabolic comorbidities. In multivariate analysis, age (OR 0.85, CI 95% 0.82-0.87) and significant fibrosis (OR 1.83; CI 95%1.10-3.03) remained independently associated with GH, regardless of the presence of metabolic alterations and nephrotoxic drugs. GH, an early marker of renal damage, is highly prevalent in MASLD and is associated with hepatic fibrosis. GH may be considered an early marker of both liver and renal disease and its recognition could prompt the management of risk factors aimed at preventing the progression of both hepatic and renal disease.

Association between input/weight ratio and acute kidney injury in obese critical ill patients: a propensity analysis of multicenter clinical databases

Rehydration volume may be underestimated in obese critically ill patients, which can lead to acute kidney injury (AKI). This study aimed to investigate the association between input/weight ratio (IWR) and AKI risk in obese critical patients. This retrospective observational study analyzed data from three large open databases. Patients were divided into lean and obese groups and matched 1:1 based on age, sex, APACHE II score, SOFA score, sepsis status, mechanical ventilation status, renal replacement therapy status, and hospital type. The exposure of interest was the mean IWR during the first three ICU admission days. The primary outcome was the incidence of AKI within 28 days after ICU admission. Cox regression analysis was used to evaluate the association between IWR and AKI risk. A total of 82,031 eligible patients were included in the study, with 25,427 obese patients matched with 25,427 lean patients. The IWRs were significantly lower in the obese groups in both the unmatched cohort (35.85 ± 19.05 vs. 46.01 ± 30.43 ml/kg, p < 0.01) and the matched cohort (36.13 ± 19.16 vs. 47.34 ± 31.13 ml/kg, p < 0.01). An increase in IWR was significantly associated with decreased creatinine levels, increased urine output and a lower AKI risk. The interaction terms of IWR and obesity were significantly associated with decreased AKI incidence in both the unmatched cohort (hazard ratio [HR] = 0.97, 95% CI 0.96-0.97, p < 0.01) and the matched cohort (HR = 0.97, 95% CI 0.96-0.97, p < 0.01). Inadequate rehydration of patients with obesity may contribute to an increased risk of AKI in patients with obesity. These results highlight the need for better rehydration management in patients with obesity.

Anemia and Hypoxia Impact on Chronic Kidney Disease Onset and Progression: Review and Updates

Chronic kidney disease (CKD) is caused by hypoxia in the renal tissue, leading to inflammation and increased migration of pathogenic cells. Studies showed that leukocytes directly sense hypoxia and respond by initiating gene transcription, encoding the 2-integrin adhesion molecules. Moreover, other mechanisms participate in hypoxia, including anemia. CKD-associated anemia is common, which induces and worsens hypoxia, contributing to CKD progression. Anemia correction can slow CKD progression, but it should be cautiously approached. In this comprehensive review, the underlying pathophysiology mechanisms and the impact of renal tissue hypoxia and anemia in CKD onset and progression will be reviewed and discussed in detail. Searching for the latest updates in PubMed Central, Medline, PubMed database, Google Scholar, and Google search engines were conducted for original studies, including cross-sectional studies, cohort studies, clinical trials, and review articles using different keywords, phrases, and texts such as "CKD progression, anemia in CKD, CKD, anemia effect on CKD progression, anemia effect on CKD progression, and hypoxia and CKD progression". Kidney tissue hypoxia and anemia have an impact on CKD onset and progression. Hypoxia causes nephron cell death, enhancing fibrosis by increasing interstitium protein deposition, inflammatory cell activation, and apoptosis. Severe anemia correction improves life quality and may delay CKD progression. Detection and avoidance of the risk factors of hypoxia prevent recurrent acute kidney injury (AKI) and reduce the CKD rate. A better understanding of kidney hypoxia would prevent AKI and CKD and lead to new therapeutic strategies.

Metformin reduces insulin resistance and attenuates progressive renal injury in prepubertal obese Dahl salt-sensitive rats

Prepubertal obesity is currently an epidemic and is considered as a major risk factor for renal injury. Previous studies have demonstrated that insulin resistance contributes to renal injury in obesity, independent of diabetes. However, studies examining the relationship between insulin resistance and renal injury in obese children are lacking. Recently, we reported that progressive renal injury in Dahl salt-sensitive (SS) leptin receptor mutant (SSLepRmutant) rats was associated with insulin resistance before puberty. Therefore, the aim of the present study was to examine whether decreasing insulin resistance with metformin will reduce renal injury in SSLepRmutant rats. Four-wk-old SS and SSLepRmutant rats were separated into the following two groups: 1) vehicle and 2) metformin (300 mg/kg/day) via chow diet for 4 wk. Chronic administration of metformin markedly reduced insulin resistance and dyslipidemia in SSLepRmutant rats. We did not detect any differences in mean arterial pressure between vehicle and metformin-treated SS and SSLepRmutant rats. Proteinuria was significantly greater in SSLepRmutant rats versus SS rats throughout the study, and metformin administration significantly reduced proteinuria in SSLepRmutant rats. At the end of the protocol, metformin prevented the renal hyperfiltration observed in SSLepRmutant rats versus SS rats. Glomerular and tubular injury and renal inflammation and fibrosis were significantly higher in vehicle-treated SSLepRmutant rats versus SS rats, and metformin reduced these parameters in SSLepRmutant rats. These data suggest that reducing insulin resistance with metformin prevents renal hyperfiltration and progressive renal injury in SSLepRmutant rats before puberty and may be therapeutically useful in managing renal injury during prepubertal obesity.NEW & NOTEWORTHY Childhood/prepubertal obesity is a public health concern that is associated with early signs of proteinuria. Insulin resistance has been described in obese children. However, studies investigating the role of insulin resistance during childhood obesity-associated renal injury are limited. This study provides evidence of an early relationship between insulin resistance and renal injury in a rat model of prepubertal obesity. These data also suggest that reducing insulin resistance with metformin may be renoprotective in obese children.

Effectiveness and Safety of Direct Oral Anticoagulants for Stroke Prevention in Atrial Fibrillation Patients With Extreme Obesity

Direct oral anticoagulants (DOACs) are a favored treatment to prevent stroke in patients with atrial fibrillation (AF). There are limited data concerning the efficacy and safety of DOACs in obese. Obesity leads to wide structural and physiological changes that may affect the pharmacokinetics and pharmacodynamics of drugs. The optimal dosing strategies for DOACs in this significant and growing sub-group remain unknown. The study aimed to evaluate on a large scale the safety and efficacy of DOAC treatment in extreme obese patients with AF. In this retrospective cohort study, we included patients with AF treated with DOACs. Patients were divided according to body mass index (BMI). Study outcomes included stroke, major bleeding, and death. Between 2012 and 2017, 5183 patients with AF were included in the analysis (2,688, 2137, and 358 patients had a BMI <30, 30 to 40, and >40 accordingly). There was no significant difference in the prevalence of ischemic events (9.9%, 8.2%, and 7.5% of patients with BMI <30, 30 to 40, and >40, respectively, p = 0.088), major bleeding events (13%, 14.1%, and 11.2% of patients with BMI <30, 30 to 40, and >40, respectively, p value = 0.257) or net ischemic and major bleeding events (18.7%, 18.7%, and 15.4% of patients with BMI <30, 30 to 40, and >40 respectively, p = 0.297) between the BMI groups. In conclusion, DOACs treatment for prevention of ischemic events in AF is effective and safe through the BMI spectrum, including extreme obesity.

Kidney Considerations in Pediatric Obesity

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is a common condition and a major cause of morbidity and mortality in adults, but children and adolescents are also at risk for early kidney injury and development of CKD. Obesity contributes both directly and indirectly to the development of CKD. The purpose of this review is to describe obesity-related kidney disease (ORKD) and diabetic kidney disease (DKD) and their impact in the pediatric population.

RECENT FINDINGS

Although obesity-related CKD in childhood and adolescence is uncommon, nascent kidney damage may magnify the lifetime risk of CKD. Glomerular hyperfiltration is an early phenotype of both ORKD and DKD and typically manifests prior to albuminuria and progressive decline in GFR. Novel treatments for obesity and type 2 diabetes exerting protective effects on the kidneys are being investigated for use in the pediatric population. It is important to understand the impact of obesity on the kidneys more fully in the pediatric population to help detect injury earlier and intervene prior to the onset of irreversible progression of disease and to guide future research in this area.

Association of underweight and obesity with adverse postoperative renal outcomes in infants and young children undergoing congenital heart surgery

Postoperative acute kidney injury (AKI) is a prevalent condition and associated with increased morbidity and mortality following cardiac surgery. This study aimed to investigate the association of underweight and obesity with adverse postoperative renal outcomes in infants and young children undergoing congenital heart surgery. This retrospective cohort study included patients aged from 1 month to 5 years who underwent congenital heart surgery with cardiopulmonary bypass at the Second Xiangya Hospital of Central South University from January 2016 to March 2022. On the basis of the percentile of body mass index (BMI) for age and sex, eligible participants were divided into three nutritional groups: normal bodyweight, underweight (BMI P5), and obesity (BMI P95). Primary outcomes included postoperative AKI and major adverse kidney events within 30 days (MAKE30). Multivariable logistic regression was performed to determine the association of underweight and obesity with postoperative outcomes. The same analyses were reproduced for classifying patients using weight-for-height instead of BMI. A total of 2,079 eligible patients were included in the analysis, including 1,341 (65%) patients in the normal bodyweight group, 683 (33%) patients in the underweight group, and 55 (2.6%) patients in the obesity group. Postoperative AKI (16% vs. 26% vs. 38%; P < 0.001) and MAKE30 (2.5% vs. 6.4% vs. 9.1%; P < 0.001) were more likely to occur in the underweight and obesity groups. After adjusting for potential confounders, underweight (OR1.39; 95% CI 1.08-1.79; P = 0.008) and obesity (OR 3.85; 95% CI 1.97-7.50; P < 0.001) were found to be associated with an increased risk of postoperative AKI. In addition, both underweight (OR 1.89; 95% CI 1.14-3.14; P = 0.014) and obesity (OR 3.14; 95% CI 1.08-9.09; P = 0.035) were independently associated with MAKE30. Similar results were also found when weight-for-height was used instead of BMI.    Conclusion: In infants and young children undergoing congenital heart surgery, underweight and obesity are independently associated with postoperative AKI and MAKE30. These results may help assess prognosis in underweight and obese patients, and will guide future quality improvement efforts. What is Known: • Postoperative acute kidney injury (AKI) is prevalent and associated with increased morbidity and mortality following pediatric cardiac surgery. • Major adverse kidney events within 30 days (MAKE30) have been recommended as a patient-centered endpoint for evaluating AKI clinical trajectories. A growing concern arises for underweight and obesity in children with congenital heart disease. What is New: • Prevalence of underweight and obesity among infants and young children undergoing congenital heart surgery was 33% and 2.6%, respectively. • Both underweight and obesity were independently associated with postoperative AKI and MAKE30 following congenital heart surgery.

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.

MAFLD and Glomerular Hyperfiltration in Subjects with Prediabetes, Visceral Obesity and "Preserved" Kidney Function:A Cross-Sectional Study

AIMS

To investigate the prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD) in prediabetes, visceral obesity, and preserved kidney function, and explore whether MAFLD is associated with hyperfiltration.

METHODS

We analyzed data from 6697 Spanish civil servants, aged 18-65 years, with fasting plasma glucose ≥100 and ≤125 mg/dL (prediabetes, ADA), waist circumference ≥94 cm in men and ≥80 cm in women (visceral obesity, IDF) and de-indexed estimated glomerular filtration rate (eGFR) ≥60 mL/min, collected during occupational health visits. The association between MAFLD and hyperfiltration (eGFR >age- and sex-specific 95^th percentile) was tested by multivariable logistic regression analyses.

RESULTS

Overall, 4213 patients (62.9%) had MAFLD, and 330 (4.9%) were hyperfiltering. MAFLD was more frequent in hyperfiltering than in non-hyperfiltering subjects (86.4% vs 61.7%, P<0.001). BMI, waist circumference, systolic, diastolic, mean arterial pressure, and prevalence of hypertension were higher in hyperfiltering than in non-hyperfiltering subjects (P<0.05). MAFLD was independently associated with hyperfiltration, even after adjusting for common confounders [OR (95% CI): 3.36 (2.33-4.84), P<0.001]. In stratified analyses MAFLD potentiated age-related eGFR decline vs. non-MAFLD (P<0.001).

CONCLUSIONS

More than half of subjects with prediabetes, visceral obesity and eGFR ≥60 ml/min presented MAFLD that was associated with hyperfiltration and potentiated the age-related eGFR decline.

Impact of Baseline Clinical Variables on SGLT2i's Antiproteinuric Effect in Diabetic Kidney Disease

INTRODUCTION

Proteinuria is a major risk factor for the progression of chronic kidney disease (CKD). Sodium-glucose cotransporter 2 inhibitors (SGLT2i) demonstrated a nephroprotective and antiproteinuric effect in people with type 2 diabetes (T2DM) and proteinuric CKD. We conducted a retrospective study to evaluate clinical and laboratory variables that can help predict proteinuria reduction with SGLT2i therapy.

MATERIALS AND METHODS

Patients affected by T2DM and CKD who started any SGLT2i were included in the study. Patients were stratified into two subgroups, Responder (R) and non-Responder (nR), based upon the response to the therapy with SGLT2i, namely the reduction in a 24 h urine proteins test (uProt) of ≥30% from baseline levels. The aim of the study is to analyse differences in baseline characteristics between the two groups and to investigate the relationship between them and the proteinuria reduction. A Kruskal-Wallis test, unpaired t-test and Chi² test were used to test the difference in means and the percentage (%) between the two groups. Linear and logistic regressions were utilized to analyse the relationship between proteinuria reduction and basal characteristics.

RESULTS

A total of 58 patients were enrolled in the study: 32 patients (55.1%) were in the R group and 26 patients (44.9%) in the nR group. R's patients had a significant higher uProt at baseline (1393 vs. 449 mg/24 h, p = 0.010). There was a significant correlation between baseline uProt and proteinuria reduction with SGLT2i in both univariate (β = -0.43, CI -0.55 to -031; p < 0.001) and multivariate analyses (β = -0.46, CI -0.57 to -0.35, p < 0.001). In the multivariate analysis, there was a significant positive correlation between the estimated glomerular filtration rate (eGFR) and proteinuria reduction (β = -17, CI -31 to -3.3, p = 0.016) and a significant negative correlation with body mass index (BMI) (β = 81, CI 13 to 50, p = 0.021). The multivariate logistic regressions show a positive correlation of being in the R group with diabetic retinopathy at baseline (Odds Ratio (OR) 3.65, CI 0.97 to 13.58, p = 0.054), while the presence of cardiovascular disease (CVD) at baseline is associated with being in the nR group (OR 0.34, CI 0.09 to 1.22, p = 0.1), even if these statements did not reach statistical significance.

CONCLUSIONS

In this real-life experience, following the administration of SGLT2i, a reduction of more than 30% in proteinuria was observed in more than half of the patients, and these patients had a significantly higher baseline proteinuria value. Variables such as eGFR and BMI are variables that, considered in conjunction with proteinuria, can help predict treatment response before therapy initiation. Different phenotypes of diabetic kidney disease may have an impact on the antiproteinuric response.

Short-term evaluation of renal markers in overweight adult cats

BACKGROUND

Obesity has been proposed as an independently risk factor for chronic kidney disease (CKD) in people, but its role in feline kidney function is unknown.

OBJECTIVE

Obesity has been proposed as an independent risk factor for chronic kidney disease (CKD) in people, but its role in feline kidney function is unknown. This study prospectively evaluated the effect of overweight on the concentration of symmetric dimethylarginine (SDMA) and creatinine in a cohort of healthy cats.

METHODS

Forty healthy adult cats were included, 14 with a body condition score (BCS) = 5 and 26 with a BCS > 5. Cats were examined every 6 months, for up to 12 months. SDMA and creatinine were measured at baseline and follow-up.

RESULTS

No effect was found for time of follow-up (p = 0.072), overweight (p = 0.9442) or their interaction (p = 0.902) on SDMA, though a significant effect was found for age (p < 0.001) [older cats showing higher SDMA] and sex (p = 0.007) [male cats showing higher SDMA]. Regarding creatinine, no effect for time (p = 0.671), age (p = 0.061), overweight (p = 0.319) or the latter's interaction (p = 0.386) were found.

CONCLUSIONS

In the short term, markers of renal function did not show an association with overweight. The role of obesity in feline kidney function still warrants further evaluation.

Clinical Characteristics of Acute Kidney Injury Associated with Tropical Acute Febrile Illness

Tropical acute febrile illness (TAFI) is one of the most frequent causes of acute kidney injury (AKI). The prevalence of AKI varies worldwide because there are limited reports available and different definitions are used. This retrospective study aimed to determine the prevalence, clinical characteristics, and outcomes of AKI associated with TAFI among patients. Patients with TAFI were classified into non-AKI and AKI cases based on the Kidney Disease Improving Global Outcomes (KDIGO) criteria. Of 1019 patients with TAFI, 69 cases were classified as having AKI, a prevalence of 6.8%. Signs, symptoms, and laboratory results were significantly abnormal in the AKI group, including high-grade fever, dyspnea, leukocytosis, severe transaminitis, hypoalbuminemia, metabolic acidosis, and proteinuria. 20.3% of AKI cases required dialysis and 18.8% received inotropic drugs. Seven patients died, all of which were in the AKI group. Risk factors for TAFI-associated AKI were being male (adjusted odds ratio (AOR) 3.1; 95% CI 1.3–7.4), respiratory failure (AOR 4.6 95% CI 1.5–14.1), hyperbilirubinemia (AOR 2.4; 95% CI 1.1–4.9), and obesity (AOR 2.9; 95% CI 1.4–6). We recommend clinicians investigate kidney function in patients with TAFI who have these risk factors to detect AKI in its early stages and offer appropriate management.

Association of Body Mass Index and Acute Kidney Injury Incidence and Outcome: A Systematic Review and Meta-Analysis

This study aims to provide pooled estimates for the incidence of acute kidney injury (AKI) in overweight, obese, and normal body mass index (BMI) patients, and to assess impact of BMI on mortality and chronic kidney disease (CKD) rates. We conducted literature search using online databases to analyze outcomes of BMI. This meta-analysis included 22 studies. Compared to normal BMI, underweight, overweight, or obese patients had higher risk of having AKI. Underweight individuals had 17% lower CKD risk (relative risk [RR]: 0.83, 95% confidence interval [CI]: 0.75, 0.90) while patients that were overweight (RR: 1.15, 95% CI: 1.08, 1.22) and obese (RR: 1.21, 95% CI: 1.10, 1.33) had higher risk of having CKD. Lower than normal BMI was associated with higher mortality risk (RR: 1.58, 95% CI: 1.35, 1.85), while being overweight or obese correlated with the decreased risk of mortality. An increased risk of AKI combined with an increased risk of mortality calls for renal protective strategies in subjects who are underweight at the time of hospital admission.

Muscle plasticity is influenced by renal function and caloric intake through the FGF23-vitamin D axis

Skeletal muscle, the main metabolic engine in the body of vertebrates, is endowed with great plasticity. The association between skeletal muscle plasticity and two highly prevalent health problems: renal dysfunction and obesity, which share etiologic links as well as many comorbidities, is a subject of great relevance. It is important to know how these alterations impact on the structure and function of skeletal muscle because the changes in muscle phenotype have a major influence on the quality of life of the patients. This literature review aims to discuss the influence of a nontraditional axis involving kidney, bone, and muscle on skeletal muscle plasticity. In this axis, the kidneys play a role as the main site for vitamin D activation. Renal disease leads to a direct decrease in 1,25(OH)₂-vitamin D, secondary to reduction in renal functional mass, and has an indirect effect, through phosphate retention, that contributes to stimulate fibroblast growth factor 23 (FGF23) secretion by bone cells. FGF23 downregulates the renal synthesis of 1,25(OH)₂-vitamin D and upregulates its metabolism. Skeletal production of FGF23 is also regulated by caloric intake: it is increased in obesity and decreased by caloric restriction, and these changes impact on 1,25(OH)₂-vitamin D concentrations, which are decreased in obesity and increased after caloric restriction. Thus, both phosphate retention, that develops secondary to renal failure, and caloric intake influence 1,25(OH)₂-vitamin D that in turn plays a key role in muscle anabolism.

Clinicopathological Characteristics and Risk Factors for Rapid eGFR Decline in Chinese Patients with Biopsy-Proven Obesity-Related Glomerulopathy

AIM

To investigate the clinicopathologic features and the related risk factors for rapid estimated glomerular filtration rate (eGFR) decline in Chinese obesity-related glomerulopathy (ORG) patients.

METHODS

A total of 63 ORG patients, who underwent a renal biopsy and received follow-up for at least 12 months, were recruited in our study. These patients were classified as rapid decliners and slow decliners based on the eGFR slope value (-5.0 mL/min/1.73 m²/year). Logistic regression analysis was used to determine the risk factors for rapid eGFR decline.

RESULTS

Of the 63 ORG patients, 48 (76.2%) were male, the mean age was 38.7 ± 9.0 years, the median of urinary protein excretion was 1.62 g/24 h, 27.0% of them had nephrotic-range proteinuria, while hypoalbuminemia was observed in 7.9% of them. The incidence of obvious hypertriglyceridemia, hypertension, glucose dysmetabolism and hyperuricemia were 71.4%, 60.3%, 36.5% and 27.0%, respectively. 13 (20.6%) patients became rapid decliners during the median 45 months of follow-up. Their mean BMI was 31.8 ± 3.6 kg/m², the median of baseline eGFR and urinary protein excretion were 71.8 (range of 30.5-118.2) mL/min/1.73 m²/year and 3.57 g/24 h, respectively. Multivariate logistic regression analysis showed that smoking (OR 9.205, 95% CI 1.704-49.740, P = 0.01), hyperuricemia (OR 5.541, 95% CI 1.079-28.460, P = 0.04) and nephrotic-range proteinuria (OR 6.128, 95% CI 1.311-28.637, P = 0.021) were the independent risk factors for rapid eGFR decline.

CONCLUSION

Chinese ORG patients were more likely to have clinical characteristics with hypertriglyceridemia, hypertension and hyperuricemia, and mild to severe degrees of urinary protein excretion at diagnosis, while patients with nephrotic-range proteinuria lacked hypoalbuminemia and hypercholesterolemia. Smoking, hyperuricemia and nephrotic-range proteinuria were independent risk factors for rapid eGFR decline in ORG patients.

Chemotherapy and Anticancer Drugs Adjustment in Obesity: A Narrative Review

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Strong Negative Association of non-HDL Cholesterol Goal Achievement With Incident CKD Among Adults With Diabetes

Context

The relative importance of the control of different metabolic risk factors for the prevention of chronic kidney disease among patients with diabetes in real life conditions is insufficiently understood.

Objective

We evaluated the effect of the achievement of glycated hemoglobin A_1c (HbA_1c), systolic blood pressure (SBP), and low-density lipoprotein cholesterol (LDLc) or non-high-density lipoprotein cholesterol (non-HDLc) goals (ABC goals) on the development of incident chronic kidney disease (iCKD) among patients with diabetes.

Methods

In a nationwide registry of all individuals diagnosed with diabetes assisted by the health system in Colombia, we analyzed the association between baseline or sustained goal achievement and development of iCKD over a 4-year follow-up. iCKD was defined as a new occurrence of an estimated glomerular filtration rate less than 60 mL/min/1.73 m², hemodialysis, peritoneal dialysis, or kidney transplant.

Results

The study included 998 790 adults with diabetes (56% female, mean age 59). There were 125 626 cases of iCKD. After adjustment for multiple confounders, a baseline SBP less than 130 mm Hg (odds ratio [OR] 0.79 [0.78-0.80]) and a baseline HbA_1c less than 7.0% (OR 0.86 [0.85-0.87]) were negatively associated with iCKD. Sustained achievement showed stronger negative associations with iCKD than just baseline achievement. Considering each goal separately, sustained non-HDLc less than 130 mg/dL had the strongest negative association with iCKD (OR 0.67 [0.65-0.69]). Patients who maintained the triple ABC goal over the entire follow-up had 32% (29-34) lower odds of developing CKD, 38% (34-42) if they additionally kept a normal body mass index (BMI). Sustained ABC control including a normal BMI was more strongly associated with a lower incidence of CKD in patients of Black race (OR 0.72 vs 0.89; P for interaction = .002).

Conclusion

At the country level, sustained achievement of ABC goals and most especially non-HDLc were associated with substantial reductions in iCKD.

Tangled relationship between insulin resistance and microalbuminuria in children with obesity

Childhood obesity represents a complex disease with a well-known cardiometabolic burden including fatty liver, type 2 diabetes, metabolic syndrome, and cardiovascular disease. From a pathogenic point of view, insulin resistance (IR) represents the key factor underlying the spectrum of these obesity consequences. As observed in adults, recent data supported the occurrence of microalbuminuria (MA) as marker of early kidney dysfunction and its potential link with cardiometabolic factors also in children with obesity. In fact, a well-documented pathophysiological hypothesis both in adults and children supported an intimate correlation with the major feature of obesity such as IR through the influence of insulin on renal hemodynamics. Based on the clinical and prognostic relevance of this relationship in daily practice (including an increased risk of chronic kidney disease development overtime), more scientific attention needs to be paid to the evaluation of early kidney damage in children with obesity. In this paper, we attempt to address three debated questions regarding the intriguing liaison between IR and MA in children with obesity: (1) What is the prevalence of pediatric MA? (2) What is the state of art of MA in children with obesity? and (3) Is there a link between IR and MA in children with obesity?

Waist-hip ratio measured by bioelectrical impedance analysis as a valuable predictor of chronic kidney disease development

Obesity is a major health problem worldwide and is associated with chronic kidney disease (CKD). Body mass index (BMI) is a common method of diagnosing obesity, but there are concerns about its accuracy and ability to measure body composition. This study evaluated the risk of CKD development in a middle-aged population in association with various body composition metrics. From a prospective cohort of 10,030 middle-aged adults, we enrolled 6727 for whom baseline and follow-up data were available. We collected data pertaining to participants' BMI, manually measured waist-hip ratio (WHR), and various measurements of bioelectrical impedance analysis (BIA), including total body fat content, muscle content, and calculated WHR, and classified the participants into quintiles accordingly. CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m² in follow-up laboratory tests. While an increase in BMI, WHR, and total body fat were associated with an elevated risk of CKD, an increase in total body muscle decreased the risk. Among the body composition metrics, WHR measured by BIA had the highest predictive value for CKD (C-statistics: 0.615). In addition, participants who were "healthy overweight, (defined as low WHR but high BMI), exhibited a 62% lower risk of developing CKD compared to those with "normal-weight obesity," (defined as high WHR despite a normal BMI). In conclusion, we suggest that central obesity measured by BIA is a more accurate indicator than BMI for predicting the development of CKD.

Is autosomal dominant polycystic kidney disease an early sweet disease?

The clinical course of autosomal dominant polycystic kidney disease (ADPKD) starts in childhood. Evidence of the beneficial impact of early nephron-protective strategies and lifestyle modifications on ADPKD prognosis is accumulating. Recent studies have described the association of overweight and obesity with rapid disease progression in adults with ADPKD. Moreover, defective glucose metabolism and metabolic reprogramming have been reported in distinct ADPKD models highlighting these pathways as potential therapeutic targets in ADPKD. Several "metabolic" approaches are currently under evaluation in adults, including ketogenic diet, food restriction, and metformin therapy. No data are available on the impact of these approaches in childhood thus far. Yet, according to World Health Organization (WHO), we are currently facing a childhood obesity crisis with an increased prevalence of overweight/obesity in the pediatric population associated with a cardio-metabolic risk profile. The present review summarizes the knowledge about the role of glucose metabolism in the pathophysiology of ADPKD and underscores the possible harm of overweight and obesity in ADPKD especially in terms of long-term cardiovascular outcomes and renal prognosis.

Review and evaluation of vancomycin dosing guidelines for obese individuals

INTRODUCTION

Vancomycin dosing decisions are informed by factors such as body weight and renal function. It is important to understand the impact of obesity on vancomycin pharmacokinetics and how this may influence dosing decisions. Vancomycin dosing guidelines use varied descriptors of body weight and renal function. There is uncertainty whether current dosing guidelines result in attainment of therapeutic targets in obese individuals.

AREAS COVERED

Literature was explored using PubMed, Embase and Google Scholar for articles from January 1980 to July 2021 regarding obesity-driven physiological changes, their influence on vancomycin pharmacokinetics and body size descriptors and renal function calculations in vancomycin dosing. Pharmacokinetic simulations reflective of international vancomycin dosing guidelines were conducted to evaluate the ability of using total, ideal and adjusted body weight, as well as Cockcroft-Gault and CKD-EPI equations to attain an area-under-the-curve to minimum inhibitory concentration ratio (AUC₂₄/MIC) target (400-650) in obese individuals.

EXPERT OPINION

Vancomycin pharmacokinetics in obese individuals remains debated. Guidelines that determine loading doses using total body weight, and maintenance doses adjusted based on renal function and adjusted body weight, may be most appropriate for obese individuals. Use of ideal body weight leads to subtherapeutic vancomycin exposure and underestimation of renal function.

Age, body mass index, and diabetes mellitus are associated with an increased risk of acute kidney injury after coronary surgery: Retrospective cohort study

Background/Aim: Cardiac surgery-associated acute kidney injury (CSA-AKI) is a significant complication of cardiac surgery and is associated with increased morbidity and mortality. Identifying risk factors can help clinicians alleviate the risk of developing CSA-AKI and associated complications. Therefore, this study aimed to identify pre-operative patient-related risk factors of CSA-AKI in patients undergoing coronary surgery. Methods: The current study was a single-center retrospective cohort study of adult patients undergoing coronary surgery with cardiopulmonary bypass (CPB) over an 8-month period. AKI was scored according to The Kidney Disease Improving Global Outcomes (KDIGO) scoring system. Patients’ age, gender, body mass index (BMI), comorbidities, KDIGO staging in AKI patients, and 30-day mortality rates were recorded. These variables were compared between AKI(−) and AKI (+) groups. Univariate binary regression analysis was performed between the variables that had statistically significant differences and AKI. Results: A total of 248 coronary surgery patients were analyzed. The overall incidence of CSA-AKI was 16.5%. Age, BMI, and the proportion of diabetic patients were significantly higher in the AKI (+) group (P = 0.04, P < 0.001, and P = 0.022, respectively). The proportion of gender, chronic obstructive pulmonary disease (COPD), hypertension (HT), baseline creatinine levels, aortic cross-clamping, cardiopulmonary bypass (CPB), total operation duration, and 30-day mortality were similar between the groups. Univariate analysis demonstrated that CSA-AKI was significantly associated with age ³ 65 years (odds ratio [OR] = 2.506; confidence interval [CI]: 1.265–4.967; P = 0.008), BMI of ³ 25 kg m-2 (OR = 8.994; CI: 1.199–67.980; P = 0.033), and diabetes mellitus (OR = 2.171; CI: 1.103–4.273; P = 0.025). Conclusion: The current study revealed that patients with increased age, BMI, and DM had a higher incidence of CSA-AKI. Therefore, even though these patient-related variables are known as non-modifiable parameters, more attention should be paid to preventing CSA-AKI during peri-operative management of these patients.

Vancomycin dosing in an obese patient with acute renal failure: A case report and review of literature

BACKGROUND

Vancomycin is the most commonly used drug for methicillin-resistant Staphylococcus aureus. The empirical clinical doses of vancomycin based on non-obese patients may not be optimal for obese ones.

CASE SUMMARY

This study reports a case of vancomycin dosing adjustment in an obese patient (body mass index 78.4 kg/m²) with necrotizing fasciitis of the scrotum and left lower extremity accompanied with acute renal failure. Dosing adjustment was performed based on literature review and factors that influence pharmacokinetic parameters are analyzed. The results of the blood drug concentration monitoring confirmed the successful application of our dosing adjustment strategy in this obese patient. Total body weight is an important consideration for vancomycin administration in obese patients, which affects the volume of distribution and clearance of vancomycin. The alterations of pharmacokinetic parameters dictate that vancomycin should be dose-adjusted when applied to obese patients. At the same time, the pathophysiological status of patients, such as renal function, which also affects the dose adjustment of the patient, should be considered.

CONCLUSION

Monitoring vancomycin blood levels in obese patients is critical to help adjust the dosing regimen to ensure that vancomycin concentrations are within the effective therapeutic range and to reduce the incidence of renal injury.

Repository Describing the Anatomical, Physiological, and Biological Changes in an Obese Population to Inform Physiologically Based Pharmacokinetic Models

Background

Obesity is associated with physiological changes that can affect drug pharmacokinetics. Obese individuals are underrepresented in clinical trials, leading to a lack of evidence-based dosing recommendations for many drugs. Physiologically based pharmacokinetic (PBPK) modelling can overcome this limitation but necessitates a detailed description of the population characteristics under investigation.

Objective

The purpose of this study was to develop and verify a repository of the current anatomical, physiological, and biological data of obese individuals, including population variability, to inform a PBPK framework.

Methods

A systematic literature search was performed to collate anatomical, physiological, and biological parameters for obese individuals. Multiple regression analyses were used to derive mathematical equations describing the continuous effect of body mass index (BMI) within the range 18.5–60 kg/m² on system parameters.

Results

In total, 209 studies were included in the database. The literature reported mostly BMI-related changes in organ weight, whereas data on blood flow and biological parameters (i.e. enzyme abundance) were sparse, and hence physiologically plausible assumptions were made when needed. The developed obese population was implemented in Matlab^® and the predicted system parameters obtained from 1000 virtual individuals were in agreement with observed data from an independent validation obese population. Our analysis indicates that a threefold increase in BMI, from 20 to 60 kg/m², leads to an increase in cardiac output (50%), liver weight (100%), kidney weight (60%), both the kidney and liver absolute blood flows (50%), and in total adipose blood flow (160%).

Conclusion

The developed repository provides an updated description of a population with a BMI from 18.5 to 60 kg/m² using continuous physiological changes and their variability for each system parameter. It is a tool that can be implemented in PBPK models to simulate drug pharmacokinetics in obese individuals.

Longitudinal Study of Glomerular Hyperfiltration in Adults with Sickle Cell Anemia: A Multicenter Pooled Analysis

Glomerular hyperfiltration is common in young sickle cell anemia patients and precedes development of overt kidney disease. In this multicenter pooled cohort, we characterized hyperfiltration and its decline to normal range in adult patients. Glomerular filtration rate (GFR) was estimated using the creatinine-based 2009 CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation omitting race adjustment and the 2021 CKD-EPI equation. Using CKD-EPI–2009, 506 patients had baseline estimated GFR (eGFR) ≥90 mL/min per 1.73 m², median age of 24 (interquartile range [IQR], 19-34) years and 5.17 years of follow-up. The prevalence of hyperfiltration (eGFR ≥140 and ≥130 mL/min per 1.73 m² for men and women, respectively) was 38.3%. Using CKD-EPI–2009, baseline hyperfiltration was less likely with older age (odds ratio [OR], 0.78; 95% confidence interval [CI], 0.73-0.83; P < .0001), male sex (OR, 0.32; 95% CI, 0.18-0.58; P = .0002), and higher weight (OR, 0.96; 95% CI, 0.94-0.99; P = .001). Using CKD-EPI–2021, hyperfiltration was similarly less likely with older age (OR, 0.75; 95% CI, 0.70-0.81; P < .0001), male sex (OR, 0.24; 95% CI, 0.13-0.44; P < .0001), and higher weight (OR, 0.97; 95% CI, 0.95-0.99; P = .004). In patients with baseline hyperfiltration, eGFR declined to normal values at a median age of 26.2 years. Using CKD-EPI–2009, this decline was associated with male sex (HR, 2.20; 95% CI, 1.26-3.87; P = .006), systolic blood pressure (hazard ratio [HR], 1.02; 95% CI, 1.01-1.04; P = .01), and hydroxyurea use (HR, 1.74; 95% CI, 1.002-3.03; P = .05). Using CKD-EPI–2021, decline of eGFR to normal was only associated with male sex (HR, 3.39; 95% CI, 2.01-5.69; P < .0001). Decline to normal eGFR range from hyperfiltration occurs earlier in males, those on hydroxyurea, and with higher systolic blood pressure.

Influence of carnosine and carnosinase-1 on diabetes-induced afferent arteriole vasodilation: implications for glomerular hemodynamics

BACKGROUND

Dysregulation in glomerular hemodynamics favors hyperfiltration in diabetic kidney disease (DKD). Although carnosine supplementation ameliorates features of DKD, its effect on glomerular vasoregulation is not known. We assessed the influence of carnosine and carnosinase-1 (CN1) on afferent glomerular arteriole vasodilation and its association with glomerular size, hypertrophy and nephrin expression in diabetic BTBR^ob/ob mice.

METHODS

Two cohorts of mice including appropriate controls were studied i.e., diabetic mice receiving oral carnosine supplementation (cohort 1) and human CN1 (hCN1) transgenic (TG) diabetic mice (cohort 2). Lumen area ratio (LAR) of the afferent arterioles and glomerular parameters were measured by conventional histology. Three-dimensional analysis using a tissue clearing strategy was also employed.

RESULTS

In both cohorts, LAR was significantly larger in diabetic BTBR^ob/ob vs non-diabetic BTBR^wt/ob mice (0.41±0.05 vs 0.26±0.07; p<0.0001) and (0.42±0.06 vs 0.29±0.04; p<0.0001), and associated with glomerular size (cohort 1: r =0.55, p=0.001; cohort 2: r=0.89, p<0.0001). LAR was partially normalized by oral carnosine supplementation (0.34±0.05 vs 0.41±0.05; p=0.004), but did not differ between hCN1 TG and wild type (WT) BTBR^ob/ob mice. In hCN1 TG mice, serum CN1 concentrations correlated with LAR (r=0.90; p=0.006). Diabetic mice displayed decreased nephrin expression and increased glomerular hypertrophy. This was not significantly different in hCN! TG BTBR^ob/ob mice (p=0,06 and p=0,08, respectively).

CONCLUSION

Carnosine and CN1 may affect intra-glomerular pressure in an opposing manner through regulation of afferent arteriolar tone. This study corroborates previous findings on the role of carnosine in the progression of DKD.

Glomerular hyperfiltration

Circulating blood is filtered across the glomerular barrier to form an ultrafiltrate of plasma in the Bowman's space. The volume of glomerular filtration adjusted by time is defined as the glomerular filtration rate (GFR), and the total GFR is the sum of all single-nephron GFRs. Thus, when the single-nephron GFR is increased in the context of a normal number of functioning nephrons, single glomerular hyperfiltration results in 'absolute' hyperfiltration in the kidney. 'Absolute' hyperfiltration can occur in healthy people after high protein intake, during pregnancy and in patients with diabetes, obesity or autosomal-dominant polycystic kidney disease. When the number of functioning nephrons is reduced, single-nephron glomerular hyperfiltration can result in a GFR that is within or below the normal range. This 'relative' hyperfiltration can occur in patients with a congenitally reduced nephron number or with an acquired reduction in nephron mass consequent to surgery or kidney disease. Improved understanding of the mechanisms that underlie 'absolute' and 'relative' glomerular hyperfiltration in different clinical settings, and of whether and how the single-nephron haemodynamic and related biomechanical forces that underlie glomerular hyperfiltration promote glomerular injury, will pave the way toward the development of novel therapeutic interventions that attenuate glomerular hyperfiltration and potentially prevent or limit consequent progressive kidney injury and loss of function.

A Wide-Proteome Analysis to Identify Molecular Pathways Involved in Kidney Response to High-Fat Diet in Mice

The etiopathogenesis of obesity-related chronic kidney disease (CKD) is still scarcely understood. To this aim, we assessed the effect of high-fat diet (HF) on molecular pathways leading to organ damage, steatosis, and fibrosis. Six-week-old male C57BL/6N mice were fed HF diet or normal chow for 20 weeks. Kidneys were collected for genomic, proteomic, histological studies, and lipid quantification. The main findings were as follows: (1) HF diet activated specific pathways leading to fibrosis and increased fatty acid metabolism; (2) HF diet promoted a metabolic shift of lipid metabolism from peroxisomes to mitochondria; (3) no signs of lipid accumulation and/or fibrosis were observed, histologically; (4) the early signs of kidney damage seemed to be related to changes in membrane protein expression; (5) the proto-oncogene MYC was one of the upstream transcriptional regulators of changes occurring in protein expression. These results demonstrated the potential usefulness of specific selected molecules as early markers of renal injury in HF, while histomorphological changes become visible later in obesity-related CDK. The integration of these information with data from biological fluids could help the identification of biomarkers useful for the early detection and prevention of tissue damage in clinical practice.

Glomerular resistances predict long-term GFR decline in type 2 diabetic patients without overt nephropathy: a longitudinal subgroup analysis of the DEMAND trial

AIMS

Investigating whether and to what extent changes in glomerular hemodynamic parameters, beyond glomerular hyperfiltration, could predict glomerular filtration rate (GFR) decline in hypertensive, non-proteinuric type 2 diabetic patients.

MATERIALS AND METHODS

We estimated baseline afferent (Ra) and efferent (Re) arteriolar resistances and glomerular hydrostatic pressure in 60 consecutive patients from DEMAND study, using the Gomez' equations. Baseline renal plasma flow was measured by para-aminohippurate plasma clearance, and GFR was measured by iohexol plasma clearance at baseline and every 6 months for a median of 4.0 years [IQR 3.5-4.0 years]. Patients with a GFR decline > or ≤ 3 mL/min/1.73 m²/year were categorized as "Progressors" and "Non-progressors," respectively. Predictors of GFR decline were studied by univariable and multivariable logistic regression analysis.

RESULTS

•The GFR declined by a median [IQR] of 4.06 [5.46-2.00] mL/min/1.73 m²/year in the study group as a whole and by 5.35 [6.60-4.48] mL/min/1.73 m²/year and 1.71 [2.14-1.33] mL/min/1.73 m²/year in Progressors and Non-progressors, considered separately. Progressors had a higher baseline Ra (3487.3 ± 1349.3 dyne•sec•cm^-5 vs. 2877.0 ± 668.9 dyne•sec•cm^-5, p < 0.05) and higher Ra/Re ratio (1.4 ± 0.5 vs. 1.1 ± 0.3, p < 0.01) than Non-progressors. At multivariable logistic regression analysis, Ra/Re ratio and arterial hypertension duration were independently associated with GFR decline (odds ratio [95% CI] 8.50 [1.56-46.28] and 1.14 [1.01-1.28]), respectively.

CONCLUSIONS

Increased Ra/Re ratio and arterial hypertension duration predict early GFR decline in hypertensive non-proteinuric type 2 diabetic patients. These findings could be explained by glomerular hypoperfusion and chronic ischemic injury related to pre-glomerular arteriolar narrowing.

CLINICAL TRIAL REGISTRATION

DEMAND, NCT00157586, September 12, 2005.

Glomerular Biomechanical Stress and Lipid Mediators during Cellular Changes Leading to Chronic Kidney Disease

Hyperfiltration is an important underlying cause of glomerular dysfunction associated with several systemic and intrinsic glomerular conditions leading to chronic kidney disease (CKD). These include obesity, diabetes, hypertension, focal segmental glomerulosclerosis (FSGS), congenital abnormalities and reduced renal mass (low nephron number). Hyperfiltration-associated biomechanical forces directly impact the cell membrane, generating tensile and fluid flow shear stresses in multiple segments of the nephron. Ongoing research suggests these biomechanical forces as the initial mediators of hyperfiltration-induced deterioration of podocyte structure and function leading to their detachment and irreplaceable loss from the glomerular filtration barrier. Membrane lipid-derived polyunsaturated fatty acids (PUFA) and their metabolites are potent transducers of biomechanical stress from the cell surface to intracellular compartments. Omega-6 and ω-3 long-chain PUFA from membrane phospholipids generate many versatile and autacoid oxylipins that modulate pro-inflammatory as well as anti-inflammatory autocrine and paracrine signaling. We advance the idea that lipid signaling molecules, related enzymes, metabolites and receptors are not just mediators of cellular stress but also potential targets for developing novel interventions. With the growing emphasis on lifestyle changes for wellness, dietary fatty acids are potential adjunct-therapeutics to minimize/treat hyperfiltration-induced progressive glomerular damage and CKD.

Effects of hyperuricaemia, with the superposition of being overweight and hyperlipidaemia, on the incidence of acute kidney injury following cardiac surgery: a retrospective cohort study

OBJECTIVES

Acute kidney injury (AKI) is a common complication of cardiac surgery. This study aimed to explore the effects of hyperuricaemia, being overweight and hyperlipidaemia as risk factors for AKI in patients following cardiac surgery (cardiac surgery-associated acute kidney injury (CSA-AKI)).

DESIGN

Retrospective observational study.

SETTING

University teaching, grade-A tertiary hospital in Shanghai, China.

PARTICIPANTS

Patients who underwent cardiac surgery from July 2015 to December 2015 in Zhongshan Hospital, Fudan University.

MAIN OUTCOME MEASURES

We investigated the effect of hyperuricaemia, in combination with being overweight and hyperlipidaemia, on the risk of CSA-AKI.

RESULTS

A total of 1420 patients were enrolled. The AKI incidence in the highest uric acid group was 44.4%, while that in the lowest uric acid group was 28.5% (p<0.001). Patients in the higher uric acid quartiles were more likely to be overweight and hyperlipidaemic at the same time (p<0.001). Multivariate logistic regression analysis showed that hyperuricaemia was an independent risk factor for AKI (OR=1.237, 95% CI 1.095 to 1.885; p=0.009); being overweight or hyperlipidaemia alone was not an independent risk factor, but the combination of being overweight and hyperlipidaemia was (OR=1.544, 95% CI 1.059 to 2.252; p=0.024). In the final model, the OR value increased to 3.126 when hyperuricaemia was combined with being overweight and hyperlipidaemia, and the Hosmer-Lemeshow test showed that all three models fit well (p=0.433, 0.638 and 0.597, respectively).

CONCLUSIONS

The combination of being overweight and having hyperlipidaemia was an independent risk factor, but being overweight or having hyperlipidaemia alone was not. The combination of hyperuricaemia, being overweight and hyperlipidaemia further increased the risk of CSA-AKI.