Approximately 30% of steroid-resistant nephrotic syndromes are attributed to monogenic disorders that involve 27 genes. Mutations in KANK family members have also been linked to nephrotic syndrome; however, the precise mechanism remains elusive. To investigate this, podocyte-specific Kank1 knockout mice were generated to examine phenotypic changes. In the initial assessment under normal conditions, Kank1 knockout mice showed no significant differences in the urinary albumin-creatinine ratio, blood urea nitrogen, serum creatinine levels, or histological features compared to controls. However, following kidney injury with adriamycin, podocyte-specific Kank1 knockout mice exhibited a significantly higher albumin-creatinine ratio and a significantly greater sclerotic index than control mice. Electron microscopy revealed more extensive foot process effacement in the knockout mice than in control mice. In addition, KANK1-deficient human podocytes showed increased detachment and apoptosis following adriamycin exposure. These findings suggest that KANK1 may play a protective role in mitigating podocyte damage under pathological conditions.

Glucagon-like peptide-1 (GLP-1) is an incretin hormone that acts on the pancreas to increase insulin and decrease glucagon secretion. Albuminuria is the pivotal marker for diabetic nephropathy, which is the leading microvascular complication of diabetes mellitus. Most of the previous studies mainly focused on the clinical trials of the therapeutic renal protective effect after administration of GLP-1 receptor agonists (GLP-1 RAs), not prior to administration. Therefore, this study aimed to investigate the association between fasting plasma GLP-1 levels and albuminuria before GLP-1 RA administration. A cross-sectional study was designed to evaluate the association between fasting plasma GLP-1 levels and albuminuria in patients with type 2 diabetes mellitus (T2DM). A total of 68 T2DM participants were analyzed from the data at Wonkwang University Hospital in Iksan, Korea. Logistic regression analysis was performed to evaluate the odds ratio (OR) and 95% confidence interval (CI) of the incidence of albuminuria between the GLP-1 low group (Group L) and the high group (Group H). The OR (95% CI) for the incidence of albuminuria comparing the Group L with the Group H of fasting plasma GLP-1 levels was 3.410 (1.160-10.023), p = 0.026 after adjustment for age, gender, fasting plasma glucose, HbA1c, C-peptide, the use of ACE inhibitors or ARBs, SGLT-2 inhibitors, and DPP-4 inhibitors. As a continuous variable, the OR (95% CI) for the incidence of albuminuria associated with the reduction of each 1 pmol/L in fasting plasma GLP-1 levels was 1.673 (1.173-1.870), p = 0.018, after full adjustment. This study showed the negative association between fasting plasma GLP-1 levels and the incidence of albuminuria in Korean patients with T2DM, before GLP-1 RA administration. This result suggests that endogenous GLP-1 may play a role in attenuating albuminuria.

Cadmium (Cd) is a pervasive, toxic environmental pollutant that preferentially accumulates in tubular epithelium of the kidney. Current evidence suggests that the cumulative burden of Cd here leads to progress loss of the glomerular filtration rate (GFR). In this study, we have quantified changes in estimated GFR (eGFR) and albumin excretion (Ealb) in according to levels of blood Cd ([Cd]b) and excretion of Cd (ECd) after adjustment for confounders. ECd and Ealb were normalized to creatinine clearance (Ccr) as ECd/Ccr and Ealb/Ccr. Among 482 residents of Cd-polluted and non-polluted regions of Thailand, 8.1% had low eGFR and 16.9% had albuminuria, (Ealb/Ccr)×100 ≥ 20 mg/L filtrate. In the low Cd burden group, (ECd/Ccr) ×100 < 1.44 µg/L filtrate, eGFR did not correlate with ECd/Ccr (β = 0.007), while an inverse association with ECd/Ccr was found in the medium (β =−0.230) and high-burden groups (β =−0.349). Prevalence odds ratios (POR) for low eGFR were increased in the medium (POR 8.26) and high Cd burden groups (POR 3.64). Also, eGFR explained a significant proportion of Ealb/Ccr variation among those with middle (η2 0.093) and high [Cd]b tertiles (η2 0.132), but did not with low tertile (η2 0.001). With adjustment of eGFR, age and BMI, POR values for albuminuria were increased in the middle (POR 2.36) and high [Cd]b tertiles (POR 2.74) and those with diabetes (POR 6.02) and hypertension (2.05). These data argue that ECd/Ccr of 1.44 µg/L filtrate (0.01−0.02 µg/g creatinine) could determine a Cd threshold level from which protective exposure guidelines should be formulated.

Introduction: Elevated albuminuria is an important outcome of diabetic complications and metabolic syndrome (MetS), the complex metabolic abnormalities manifested as glucose intolerance, hypertension, and dyslipidemia and enlarged waist circumference. These coexisting cardio-metabolic abnormalities are also associated with oxidative stress and low grade inflammation. Vitamin C (vitC) has long been recognized as hydrophilic antioxidant and blocker of oxidative stress which also has a protective role of MetS and kidney disease. Objective: The aim of this study was to identify the predictive effect of vitC deficiency on kidney disease among patients who developed metabolic syndrome. Method and procedures: To meet this objective, the National Health and Nutrition Examination Survey (NHANES) 2007-2008 data were used. NHANES represents the civilian, non-institutionalized US population data implemented for continuous system of monitoring health, nutritional status and well-being in the US. The predictive power of MetS on AU and vitC deficiency (vitC < 0.25 mg/dl) as effect modifier was assessed with binary logistic regression. Age, gender, race and BMI were used as covariates. Results: Among the respondents, 1.9% of the US population had risk of kidney damage, whereas 14.5 % of respondents had MetS. MetS was significantly positively correlated with AU (p < 0.01). Higher elevation of albuminuria creatinine ratio (ACR) was found in participants with VCD. The regression models developed in this study showed that the severity of kidney disease measured by ACR was increased among individuals who developed both VCD and MetS compared with individuals who developed MetS only (AOR=5.53; 95% CI: 2.73, 11.21). Increasing age and being African-American in race were independently associated with elevated AU. Conclusion: Specific considerations tailored to metabolic syndrome, vitamin C and kidney diseases measured by ACR screening and monitoring mechanisms at the community level is critical to tackle further medical complications. Moreover, the role of VitC fortified foods on prevention of kidney diseases among patients with MetS warrant further investigation.

Introduction: Elevated albuminuria is an important outcome of diabetic complications and metabolic syndrome (MetS), the complex metabolic abnormalities manifested as glucose intolerance, hypertension, and dyslipidemia and enlarged waist circumference. These coexisting cardio-metabolic abnormalities are also associated with oxidative stress and low grade inflammation. Vitamin C (vitC) has long been recognized as hydrophilic antioxidant and blocker of oxidative stress which also has a protective role of MetS and kidney disease. Objective: The aim of this study was to identify the predictive effect of vitC deficiency on kidney disease among patients who developed metabolic syndrome. Method and procedures: To meet this objective, the National Health and Nutrition Examination Survey (NHANES) 2007-2008 data were used. NHANES represents the civilian, non-institutionalized US population data implemented for continuous system of monitoring health, nutritional status and well-being in the US. The predictive power of MetS on AU and vitC deficiency (vitC < 0.25 mg/dl) as effect modifier was assessed with binary logistic regression. Age, gender, race and BMI were used as covariates. Results: Among the respondents, 1.9% of the US population had risk of kidney damage, whereas 14.5 % of respondents had MetS. MetS was significantly positively correlated with AU (p < 0.01). Higher elevation of albuminuria creatinine ratio (ACR) was found in participants with VCD. The regression models developed in this study showed that the severity of kidney disease measured by ACR was increased among individuals who developed both VCD and MetS compared with individuals who developed MetS only (AOR=5.53; 95% CI: 2.73, 11.21). Increasing age and being African-American in race were independently associated with elevated AU. Conclusion: Specific considerations tailored to metabolic syndrome, vitamin C and kidney diseases measured by ACR screening and monitoring mechanisms at the community level is critical to tackle further medical complications. Moreover, the role of VitC fortified foods on prevention of kidney diseases among patients with MetS warrant further investigation.

Chronic exposure to the nephrotoxic metal pollutant, cadmium (Cd), has been associated with the pathogenesis of hypertension, but so far, the mechanism has not been well defined. We hypothesize that exposure to Cd causes a decline in the glomerular filtration rate (GFR), which in turn, causes a rise in blood pressure. Data were collected from 447 Thai subjects with a mean age of 51.1 years, of which 48.8% had hypertension, 15.4% had diabetes and 6.9% had an estimated GFR (eGFR) below 60 mL/min/1.73m2 (low eGFR). The mean blood Cd and mean urinary Cd concentrations were 2.75 and 4.23 µg/L, respectively. Prevalence odds ratio (POR) for hypertension rose twofold in those with a medium Cd burden and blood Cd levels of 0.61-1.69 µg/L. In the hypertensive group, the eGFR was inversely associated with age (β =−0.517), the Cd excretion rate (β = −0.177), and diabetes (β = −0.175). Mean eGFR in those with hypertension was 7.5 mL/min/1.73m2 lower than those who were normotensive with the same Cd body burden. In addition, higher systolic blood pressure (SBP) values were associated with older age (β = 0.243), higher BMI (β = 0.113), lower eGFR (β = −0.106) and diabetes (β = 0.216). Mean SBP in those who had low eGFR and medium and heavy Cd body burden was 9.5 mmHg higher than those with the same Cd body burden and a normal eGFR. Thus, chronic environmental exposure to Cd that produces urinary and blood Cd levels of 0.57-0.61 µg/L, increases the risk of hypertension, and this could be mediated by a declining GFR.

Cadmium (Cd) is a metal with no nutritional or physiological value, but is found in most people because it is a contaminant in nearly all food types. The intestinal absorption rate determines the body burden of Cd because humans lack a physiologic mechanism for excretion of the metal. Most acquired Cd accumulates in the kidneys, in which the Cd content increases through age 50 but falls thereafter. The decline from maximal kidney content is probably due to release of Cd from injured tubular cells into urine and replacement of destroyed nephrons by scar tissue. Chronic kidney disease is diagnosed when the estimated glomerular filtration rate (eGFR) falls below 60 mL/min/1.73 m2, or when albuminuria is present. Albuminuria is defined as an albumin-to-creatinine ratio ≥ 30 mg/g creatinine in women or ≥ 20 mg/g creatinine in men that persists for at least 3 months. Generally, Cd-induced reductions in eGFR are not reversible, and Cd nephropathy may progress to end-stage kidney disease. There is no evidence that elimination of current environmental exposure can reverse Cd nephropathy, and no theoretical reason to believe that such a reversal is possible. This review provides an update of knowledge concerning CKD in population environmentally exposed to Cd. Special attention is devoted to mechanisms of Cd-induced albuminuria concurrently with eGFR reductions, and the difficult challenge of exposure guidelines sufficient to eliminate the risk of Cd-induced CKD is addressed.