Urinary Albumin Excretion Research Articles

To analyse the correlation between UAER and eGFR and the risk factors for reducing eGFR in patients with type 2 diabetes

ObjectiveTo analyse the correlation between urinary albumin excretion rate (UAER) and estimated glomerular filtration rate (eGFR) and the risk factors for reducing eGFR in patients with type 2 diabetes mellitus (T2DM).MethodsA total of 431 T2DM patients admitted between January 2019 and March 2020 were selected and divided into two groups according to eGFR level. Comparing the differences between baseline data and clinical indicators, multivariate logistic regression was used to analyse the risk factors of eGFR reduction and to analyse the association between UAER and eGFR.ResultsIn total, 167 patients were included in the study group and 264 patients were included in the conventional group. The study group participants were older, had longer diabetes duration, and had higher fatty liver, peripheral vascular disease (PVD), hypertension prevalence, and mean body mass index (P < 0.05). The levels of various indicators were lower than those of the conventional group (P < 0. 05). Additionally, PVD, nocturnal systolic blood pressure, fatty liver, and beta-2-microglobulin (β 2-MG) were independent risk factors for eGFR decline, with high density lipoprotein (HDL) and fasting C-peptide (CP) as protective factors. There was no obvious correlation between UAER and eGFR.ConclusionPeripheral vascular disease, systolic blood pressure, fatty liver, and beta-2-microglobulin are risk factors for decreased eGFR levels in patients with T2DM, which should be applied for control DKD. HDL and fasting CP have important effects on maintaining eGFR, and blood pressure and fasting CP can be used as new targets for subsequent diabetic kidney disease treatment.

Serum peroxiredoxin-4, a biomarker of oxidative stress, associates with new-onset chronic kidney disease: A population-based cohort study

BackgroundChronic Kidney Disease (CKD), is often detected late due to its asymptomatic nature in the early stage of the disease. Overproduction of reactive oxygen species contributes to various pathological processes through oxidative stress (OS), impacting on cellular structures and functions with previous studies suggesting a link between OS and CKD progression. This study investigated the association between serum peroxiredoxin-4 (Prx4), a biomarker of oxidative stress, and the development of CKD in the general population. MethodsThis study featured data from the Prevention of REnal and Vascular ENd-stage Disease (PREVEND) cohort, involving 5341 participants without CKD at baseline who underwent extensive prospective health evaluations. Serum Prx4 levels were quantified using an immunoluminometric assay. The primary outcome was new-onset CKD as defined by the composite of urinary albumin excretion (UAE) > 30 mg/24-h, an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2, or both. ResultsBaseline median Prx4 level was 0.65 [interquartile range (IQR): 0.42–1.04] U/L, median eGFR was 98 [IQR: 87–108] mL/min/1.73 m2, and median UAE was 8.1 [IQR: 6.0–12.1] mg/L. During a median follow-up of 10.4 [IQR: 6.3–11.4] years, 867 (16.2 %) patients developed new-onset CKD. Higher Prx4 levels were significantly associated with an increased risk of CKD (hazard ratio (HR) per doubling: 1.29 [95 % confidence interval (CI): 1.21–1.37], p < 0.001), also after adjustment for risk factors including sex, smoking status, systolic blood pressure, high-sensitive C-reactive protein, chronic heart failure, diabetes mellitus and dyslipidemia (HR per doubling: 1.16 [1.06–1.24], p < 0.001). Sensitivity analyses confirmed the robustness of these findings. ConclusionsThis study supports the hypothesis that systemic oxidative stress, reflected by higher serum Prx4 levels, is significantly associated with the risk of developing CKD in the general population. These findings suggest that Prx4 could be a valuable biomarker for early risk stratification and prevention strategies in CKD management.

The associations between functional vitamin K status and all-cause mortality, cardiovascular disease and end-stage kidney disease in persons with type 1 diabetes.

Vitamin K deficiency is common in persons with kidney disease, which is a known complication of diabetes. We aimed to assess the association of vitamin K status as reflected by plasma dephosphorylated-uncarboxylated matrix Gla protein (dp-ucMGP) with mortality, cardiovascular disease (CVD) and progression to end-stage kidney disease (ESKD) in persons with type 1 diabetes. We analysed plasma dp-ucMGP in stored baseline samples from a cohort of 667 persons with type 1 diabetes (baseline visit: 2009-2011). Information on mortality and CVD was obtained through linkage to registers. Cox-proportional hazards models were applied to estimate hazard ratios (HRs) of mortality, CVD and ESKD per one doubling of dp-ucMGP. A total of 53 deaths were recorded during follow-up. Persons with higher dp-ucMGP (reflecting lower vitamin K status) had higher mortality in the unadjusted model (HR: 2.06 [95% confidence interval-CI: 1.22-3.45]), but not in the fully adjusted model (HR: 0.88 [95% CI: 0.44-1.73]). Particularly, adjustment for glomerular filtration rate and urinary albumin excretion rate attenuated the HR. A similar pattern was observed in unadjusted models for incidence of CVD (HR: 1.58 [95% CI: 1.03-2.42]) and risk of ESKD (HR: 7.62 [95% CI: 4.25-13.68]). In the fully adjusted models, the HRs became statistically insignificant. In persons with type 1 diabetes, lower vitamin K status was associated with higher mortality, CVD and progression to ESKD, however, not after adjustment for other risk factors. Interventional studies are needed to elucidate the role of vitamin K in persons with type 1 diabetes.

Empagliflozin protects the kidney by reducing toxic ALB (albumin) exposure and preventing autophagic stagnation in proximal tubules

ABSTRACT The renoprotective effects of SLC5A2/SGLT2 (solute carrier 5 (sodium/glucose cotransporter), member 2) inhibitors have recently been demonstrated in non-diabetic chronic kidney disease (CKD), even without overt albuminuria. However, the mechanism underlying this renoprotection is largely unclear. We investigated the renoprotective mechanisms of the SLC5A2 inhibitor empagliflozin with a focus on ALB (albumin) reabsorption and macroautophagy/autophagy in proximal tubules using wild-type or drug-inducible lrp2/Megalin or atg5 knockout mice with high-fat diet (HFD)-induced obesity or 5/6 nephrectomy that elevated intraglomerular pressure without overt albuminuria. Empagliflozin treatment of HFD-fed mice reduced several hallmarks of lipotoxicity in the proximal tubules, such as phospholipid accumulation in the lysosome, inflammation and fibrosis. Empagliflozin, which decreases intraglomerular pressure, not only reduced the HFD-induced increase in ALB reabsorption via LRP2 in the proximal tubules (i.e. total nephron ALB filtration), as assessed by urinary ALB excretion caused by genetic ablation of Lrp2, but also ameliorated the HFD-induced imbalance in circulating ALB-bound fatty acids. Empagliflozin alleviated the HFD-induced increase in autophagic demand and successfully prevented autophagic stagnation in the proximal tubules. Similarly, empagliflozin decreased ALB exposure and autophagic demand in 5/6 nephrectomized mice. Finally, empagliflozin reduced HFD-induced vulnerability to ischemia–reperfusion injury, whereas LRP2 blockade and atg5 ablation separately diminished this effect. Our findings indicate that empagliflozin reduces ALB exposure and prevents autophagic stagnation in the proximal tubules even without overt albuminuria. Autophagy improvement may be critical for the renoprotection mediated by SLC5A2 inhibition.

9210 Nephron specific ATP6AP2 knockout reduces renal fat accumulation in mice consuming high fat diet

Abstract Disclosure: S.A. Culver: None. J. Balugo: None. M. Jansen: None. T. Harris: None. H.M. Siragy: None. Diet induced obesity causes increased renal fat accumulation in both humans and mice which contributes to obesity related kidney injury. We have previously shown that mice with nephron specific ATP6AP2 knockout (KO) consuming high fat diet (HFD) are resistant to weight gain due to increased urinary excretion of glucose, albumin, and fatty acids. Magnetic resonance imaging (MRI) is a useful imaging modality for quantifying organ fat content in live animals though there are few reports of its use quantifying fat in murine kidney. We hypothesized that nephron specific ATP6AP2 knockout inhibits renal fat accumulation with HFD and that we would be able to detect this using MRI. Eight-week-old male wild type (WT) or inducible nephron specific ATP6AP2 KO mice underwent either induction with oral doxycycline or received sucrose water as controls before being placed on either normal diet (ND) (12% fat) or HFD (45% fat) for 3 months. Mice were then imaged using a 9.4 Tesla Bruker BioSpin MRI to determine both liver and kidney cortex fat content. The mean weight of WT HFD mice was 36.03 g compared to 29.03 g in WT ND controls. ND fed and HFD fed KO mice weighed 22.74 g and 23.03 g respectively. MRI showed significant 67% (p&amp;lt;0.05) increase in liver fat content in WT HFD compared to WT ND fed controls, confirming the ability of our MRI technique to detect expected differences in organ fat content. In renal cortex, MRI detected a 54% (p&amp;lt;0.05) increase in lipid content for WT HFD mice compared to WT ND controls. Nephron specific ATP6AP2 KO on HFD demonstrated reduced renal cortical lipid content by 36% (p&amp;lt;0.05) compared to WT HFD controls. These results indicate that ATP6AP2 KO is associated with reduced renal fat accumulation that is measurable with in vivo MRI. MRI therefore represents a valuable tool for studying renal sequelae of obesity in live murine models. Future investigation should examine whether ATP6AP2 KO prevents renal lipotoxicity and kidney injury in the setting of obesity. Presentation: 6/3/2024

Association of urinary albumin excretion with all-cause and cardiovascular mortality among patients with rheumatoid arthritis: a national prospective study.

Rheumatoid arthritis (RA) patients suffering from chronic renal insufficiency tend to exhibit subtle manifestations at the beginning. Urine albumin to creatinine ratio (ACR) is a sensitive indicator for early assessment of renal function. However, it is unclear whether it serves as an independent risk factor influencing the prognosis of RA patients. National Health and Nutrition Examination Survey (NHANES) data from 2009-2018 were included. Kaplan-Meier (K-M) curves were plotted to compare the cumulative survival probability of RA patients with different urinary albumin excretion. The association of ACR with mortality among RA patients was investigated with Cox regression model, restricted cubic spline (RCS) and stratified analyses. The prognostic efficacy of ACR and estimated glomerular filtration rate (eGFR) was evaluated by receiver operating characteristic (ROC) curves. The Cox regression model adjusted with covariates showed a 53% (HR 1.53, 95% CI 1.06-2.21) increase in all-cause mortality and a statistically non-significant increase in cardiovascular disease (CVD) mortality in RA patients with microalbuminuria (30mg/g ≤ACR<300mg/g). ACR≥300mg/g was associated with an increase in all-cause mortality (HR 2.62, 95% CI 1.55-4.45) and CVD mortality (HR 5.67, 95% CI 1.96-16.39). RCS demonstrated a nonlinear correlation between ACR and all-cause mortality in RA patients with microalbuminuria. Subgroup analysis showed that CVD mortality was higher in RA patients with microalbuminuria characterized by the following features: female, other ethnicity, eGFR≥60 ml/min/1.73 m2, hypertension or hyperlipidemia. Compared with eGFR, ACR provided better prognostic efficacy than eGFR with higher values of the area under the curve (AUC) for all-cause mortality (AUC=0.683, 95% CI 0.613-0.754) and CVD mortality (AUC=0.681, 95% CI 0.541-0.820). ACR is an independent risk factor affecting the prognosis of RA patients. The all-cause mortality was increased in RA patients with albuminuria. There was an upward trend in the CVD mortality of those with macroalbuminuria when ACR increased.

Abstract P360: MicroRNAs: Potential Biomarkers and Therapeutic Targets for Hypertensive Nephropathy

Introduction: Hypertensive nephropathy (HN) is the second most common cause of end-stage renal disease after diabetic nephropathy. miRNAs are small epigenetic modulators whose levels change in many diseases. This review summarizes the diagnostic and therapeutic potential of miRNAs in HN. Methodology: We conducted a thorough literature review on PubMed, including both retrospective and prospective studies on animal and human subjects. Additional references were sourced through cross-referencing the bibliographies of the initial articles. Results: Our literature review revealed that intra-renal levels of miR-200a, miR-141, miR-200b, miR-205, miR-429, and miR-192 were elevated in patients with HN. Conversely, intra-renal miR-204-5p levels were decreased, and further reductions in animal models using anti-miR-204-5p or miR-204 gene knockout exacerbated renal injury. Exposure of renal tissue to exogenous albumin increased intra-renal miR-184 levels, prompting further investigation into whether albumin excretion from kidney injury alters miRNA expression or if miRNA dysregulation initiates kidney injury and subsequent albumin excretion. Urinary miR-146a, miR-184, and miR-34a levels were lower in patients with albuminuria than those without, whereas urinary miR-200a levels were higher. Interestingly, urinary miR-21 levels increased before the onset of albuminuria in hypertensive mice. A positive correlation was also observed between miR-208b and miR-133a levels in blood cells and urinary albumin excretion (UAE). Notably, plasma levels of miR-let-7g-5p and miR-191-5p correlated positively with eGFR but not with UAE. Since miRNA levels varied based on the sampling source, a pivotal study identified a consistent miRNA profile in HN patients, showing that miR-208a and miR-301a were upregulated in urine yet downregulated in plasma. The therapeutic potential of miRNAs was highlighted by an animal study showing that the knockdown of miR-103a-3p can nullify albuminuria in hypertensive mice. Conclusion: The role of miRNAs in HN is increasingly evident. Studies have linked varying miRNA expression profiles in patients with HN, and specific miRNAs were detectable earlier than albuminuria. Furthermore, certain miRNAs correlate with eGFR independently of UAE. Targeting specific miRNAs, using miRNA mimics and anti-miRNAs, could underpin preventive and therapeutic strategies. These findings advocate for further research into miRNAs as potential biomarkers and therapeutic targets for HN.

SS-31 protects diabetic nephropathy progression: A systematic review of in vivo and in vitro studies

Context: Diabetic nephropathy is the leading cause of end-stage renal disease and also death in the world. Administration of Szeto-Schiller-31 (SS-31) as a potential therapeutic candidate that can decrease the renal function damage progressivity in diabetes needs to be comprehensively analyzed. Aims: To assess the protective effects of SS31 against the progressivity of diabetic nephropathy. Methods: This systematic review follows PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines 2020. Searches of databases (Pubmed, Science Direct, Scopus, ProQuest, and Springer) were done on 17 September 2023 in order to find articles related to the animal diabetic model and SS-31 treatment. Manual searches from medRxiv were also conducted to obtain additional evidence. Renal function, histopathology analysis, reactive oxygen species in vivo, and in vitro analysis were described. Results: There were six in vivo studies, each of which discussed the renal function, histopathology, and reactive oxygen species (ROS), and four in vitro studies that discussed ROS. The available data suggested that SS-31 improves kidney function by lowering urinary albumin excretion, proteinuria, serum creatinine, creatinine clearance, and BUN, supported by histopathological improvements. In addition, SS-31 also has the effect of lowering 8-hydroxy-2-deoxyguanosine (8-OHdG) level, malondialdehyde (MDA) level, and nicotinamide adenine dinucleotide phosphate (NADPH) expression. Conclusions: SS31 had a renoprotective effect that could prevent the worsening of renal function in diabetic mice. In addition, the results of histopathology and ROS analysis also support the positive results of SS-31 treatment. Further studies are required to confirm its findings.

Correlation of serum thyrotropin and thyroid hormone levels with diabetic kidney disease: a cross-sectional study

ObjectiveThe relationship between thyrotropin (TSH), free triiodothyronine (FT3), free thyroxine (FT4) and diabetic kidney disease (DKD) is still controversial, and this study analyzed the correlation between TSH, FT3, FT4 and DKD in patients with type 2 diabetes mellitus (T2DM).MethodsT2DM patients (1216) were divided into five groups based on serum TSH, FT3, and FT4 levels, differences in urinary albumin excretion rate (UACR), estimated glomerular filtration rate (eGFR) were compared. Binary logistic regression verified independent correlations among TSH, FT3, FT4 and UACR, eGFR. TSH and FT3 predictive values for DKD were analyzed using receiver operating characteristic (ROC) curves.ResultsThe prevalence of albuminuria with decreased eGFR was higher in T2DM patients with subclinical hypothyroidism and overt hypothyroidism than that in patients with normal thyroid function. TSH positively correlated with UACR (r = 0.133, p < 0.001) and positively correlated with eGFR (r = -0.218, p < 0.001), FT3 negatively correlated with UACR (r = -0.260, p < 0.001) and positively correlated with eGFR (r = 0.324, p < 0.001). With the change from the lower normal level to the increased level of TSH and the change from the higher normal level to the reduced level of FT3, the prevalence of albuminuria gradually increased, the prevalence of decreased eGFR gradually increased in TSH groups and FT3 groups. After adjusting for age, BMI, duration of diabetes, TPOAb, TGAb, smoking, drinking, hypertension, the use of anti-diabetic medications (metformin, sodium–glucose cotransporter 2 inhibitors), HbA1c, CRP, TC, TG, LDL-C, and HDL-C, both TSH and FT3 correlated with increased UACR (TSH: OR 1.253, p = 0.001; FT3: OR 0.166, p < 0.001) and decreased eGFR (TSH: OR 1.245, p < 0.001, FT3: OR 0.579, p < 0.001), but this correlation of TSH with eGFR < 60 mL/min/1.73 m2 was not found in male. The area under the ROC curve (AUC) for FT3 was greater than that for TSH (FT3: 0.64; TSH: 0.61).ConclusionsIncreased TSH and reduced FT3 levels were associated with DKD in T2DM patients, but in a sex-dependent manner. FT3 had a higher predictive value for DKD.

Association of Genetically Predicted Skipping of COL4A4 Exon 27 with Hematuria and Albuminuria.

Hematuria is an established sign of glomerular disease and can be associated with kidney failure, but there has been limited scientific study of this trait. Here, we combined genetic data from the UK Biobank with predicted gene expression and splicing from GTEx kidney cortex samples (n = 65) in a transcriptome-wide association study (TWAS) to identify additional potential biological mechanisms influencing hematuria. The TWAS using kidney cortex identified significant associations for 5 genes in terms of expression and 3 significant splicing events. Notably, we identified an association between the skipping of COL4A4 exon 27, which is genetically predicted by intronic rs11898094 (minor allele frequency 13%), and hematuria. Association between this variant was also found with urinary albumin excretion. We found independent evidence supporting the same variant predicting this skipping event in glomeruli-derived mRNA transcriptomics data (n = 245) from NEPTUNE. The functional significance of loss of exon 27 was demonstrated using the split NanoLuc-based α3α4α5(IV) heterotrimer assay, in which type IV collagen heterotrimer formation was quantified by luminescence. The causal splicing variant for this skipping event is yet to be identified. In summary, by integrating multiple data types, we identify a potential splicing event associated with hematuria and albuminuria.

J-shaped relationship of serum neurofilament light chain with urinary albumin excretion in US adults: NHANES 2013–2014

Introduction This study focuses on investigating the relationship between serum neurofilament light chain (sNfL) and urinary albumin-to-creatinine ratio (uACR) among American adults aged 25–75. Methods An analysis was conducted on information gathered from 1741 individuals aged between 25 and 75 who participated in the National Health and Nutrition Examination Survey (NHANES) during the years 2013–2014. Generalized linear models were utilized, and restricted cubic spline (RCS) analysis was conducted to assess a non-linear relationship. Results Upon adjusting for multiple variables, a non-linear inverse J-shaped relationship was observed between sNfL and uACR. Compared with individuals in quartile 1 (Q1) of sNfL (2.8–8.3), those with quartile 4 (Q4) (≥19.1) had an adjusted β for uACR of 51.57. Conclusions The study found a J-shaped curve linking sNfL and uACR in American adults, with a turning point around log(sNfL) 2.928 pg/mL.

Development and validation of a nomogram of all-cause mortality in adult Americans with diabetes

This study aimed to develop and validate a predictive model of all-cause mortality risk in American adults aged ≥ 18 years with diabetes. 7918 participants with diabetes were enrolled from the National Health and Nutrition Examination Survey (NHANES) 1999–2016 and followed for a median of 96 months. The primary study endpoint was the all-cause mortality. Predictors of all-cause mortality included age, Monocytes, Erythrocyte, creatinine, Nutrition Risk Index (NRI), neutrophils/lymphocytes (NLR), smoking habits, alcohol consumption, cardiovascular disease (CVD), urinary albumin excretion rate (UAE), and insulin use. The c-index was 0.790 (95% CI 0.779–0.801, P < 0.001) and 0.792 (95% CI: 0.776–0.808, P < 0.001) for the training and validation sets, respectively. The area under the ROC curve was 0.815, 0.814, 0.827 and 0.812, 0.818 and 0.829 for the training and validation sets at 3, 5, and 10 years of follow-up, respectively. Both calibration plots and DCA curves performed well. The model provides accurate predictions of the risk of death for American persons with diabetes and its scores can effectively determine the risk of death in outpatients, providing guidance for clinical decision-making and predicting prognosis for patients.

Alterations of urine microRNA-7977/G6PD level in patients with diabetic kidney disease and its association with dysfunction of albumin-induced autophagy in proximal epithelial tubular cells.

Diabetic kidney disease (DKD) remains as one of the leading long-term complications of type 2 diabetic mellitus (T2DM). Studies have shown that decreased expression of glucose-6-phosphate dehydrogenase (G6PD) plays an important role in DKD. However, the upstream and downstream pathways of G6PD downregulation leading to DKD have not been elucidated. We conducted a series of studies including clinical study, animal studies, and in vitro studies to explore this. First, a total of 90 subjects were evaluated including 30 healthy subjects, 30 patients with T2DM, and 30 patients with DKD. The urinary G6PD activity and its association with the clinical markers were analyzed. Multivariate linear regression analysis was used to analyze the risk factors of urinary G6PD in these patients. Then, microRNAs that were differentially expressed in urine and could bind and degrade G6PD were screened and verified in patients with DKD. After that, high glucose (HG)-cultured human kidney cells (HK-2) and Zucker diabetic fatty (ZDF) rats were used to test the roles of miR-7977/G6PD/albumin-induced autophagy in DKD. Beclin and P62 were used as markers of kidney autophagy indicators. A dual-luciferase reporter assay system was used to test the binding of G6PD by mir-7977. The plasma and urinary G6PD activity were decreased significantly in patients with DKD, accompanied by increased urinary mir-7977 level. The fasting plasma glucose (FPG), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and urinary albumin excretion were independent predictors of urinary G6PD activity, according to multiple linear regression analysis. The increased expression of miR-7977 and decreased expression of G6PD were also found in the kidney of ZDF rats with early renal tubular damage. The correlation analysis showed that beclin protein expression levels were positively correlated with kidney G6PD activity, whereas P62 protein expression was negatively correlated with kidney G6PD activity in rats. In HK-2 cells cultured with normal situation, a low level of albumin could induce autophagy along with the stimulation of G6PD, although this was impaired under high glucose. Overexpression of G6PD reversed albumin-induced autophagy in HK-2 cells under high glucose. Further study revealed that G6PD was a downstream target of miR-7977. Inhibition of miR-7977 expression led to significantly increased expression of G6PD and reversed the effects of high glucose on albumin-induced autophagy. In conclusion, our study supports a new mechanism of G6PD downregulation in DKD. Therapeutic measures targeting the miR-7977/G6PD/autophagy signaling pathway may help in the prevention and treatment of DKD.NEW & NOTEWORTHY This study provides new evidence that reduced glucose-6-phosphate dehydrogenase (G6PD) may damage the endocytosis of renal tubular epithelial cells by reducing albumin-induced autophagy. More importantly, for the first time, our study has provided evidence from humans that the decrease in urinary G6PD activity is positively associated with renal injury, and abnormal glucose and lipid metabolism may be important reasons for reduced G6PD levels. Increased miR-7977 may at least in part explain the downregulation of G6PD.

Nephron specific ATP6AP2 knockout increases urinary excretion of fatty acids and decreases renal cortical megalin expression

ATP6AP2 knockout in the renal nephron impairs receptor-mediated endocytosis, increasing urinary albumin and glucose excretion and impairing weight gain. Nonesterified fatty acids (NEFA) in urine are bound to albumin and reabsorbed in the proximal tubule through receptor-mediated endocytosis by the megalin–cubilin complex. We hypothesized that ATP6AP2 knockout increases urinary NEFA excretion through a reduction in megalin. Ten-week-old male C57BL/6 mice with nephron specific inducible ATP6AP2 knockout and noninduced controls were fed either normal diet (ND 12% fat) or high fat diet (HFD 45% fat) for 6 months. ATP6AP2 knockout significantly increased urine albumin:creatinine ratio in both ND and HFD fed mice while normalized urine NEFA concentration increased 489% and 259% in ND and HFD knockout mice compared to respective controls. Knockout decreased renal cortical megalin mRNA by 47% on ND and 49% on HFD while megalin protein expression decreased by 36% and 44% respectively. At the same time, markers of mTOR activity were increased while autophagy was impaired. Our results indicate that nephron specific ATP6AP2 knockout increases urinary NEFA excretion in the setting of impaired receptor-mediated endocytosis. Further investigation should determine whether ATP6AP2 contributes to obesity related ectopic lipid deposition in the proximal tubule.

Protein Intake and Mortality in Older Adults With Chronic Kidney Disease

Avoiding high protein intake in older adults with chronic kidney disease (CKD) may reduce the risk of kidney function decline, but whether it can be suboptimal for survival is not well known. To estimate the associations of total, animal, and plant protein intake with all-cause mortality in older adults with mild or moderate CKD and compare the results to those of older persons without CKD. Data from 3 cohorts (Study on Cardiovascular Health, Nutrition and Frailty in Older Adults in Spain 1 and 2 and the Swedish National Study on Aging and Care in Kungsholmen [in Sweden]) composed of community-dwelling adults 60 years or older were used. Participants were recruited between March 2001 and June 2017 and followed up for mortality from December 2021 to January 2024. Those with no information on diet or mortality, with CKD stages 4 or 5, or undergoing kidney replacement therapy and kidney transplant recipients were excluded. Data were originally analyzed from June 2023 to February 2024 and reanalyzed in May 2024. Cumulative protein intake, estimated via validated dietary histories and food frequency questionnaires. The study outcome was 10-year all-cause mortality, ascertained with national death registers. Chronic kidney disease was ascertained according to estimated glomerular filtration rates, urine albumin excretion, and diagnoses from medical records. The study sample consisted of 8543 participants and 14 399 observations. Of the 4789 observations with CKD stages 1 to 3, 2726 (56.9%) corresponded to female sex, and mean (SD) age was 78.0 (7.2) years. During the follow-up period, 1468 deaths were recorded. Higher total protein intake was associated with lower mortality among participants with CKD; adjusted hazard ratio (HR) for 1.00 vs 0.80 g/kg/d was 0.88 (95% CI, 0.79-0.98); for 1.20 vs 0.80 g/kg/d, 0.79 (95% CI, 0.66-0.95); and for 1.40 vs 0.80 g/kg/d, 0.73 (95% CI, 0.57-0.92). Associations with mortality were comparable for plant and animal protein (HRs, 0.80 [95% CI, 0.65-0.98] and 0.88 [95% CI, 0.81-0.95] per 0.20-g/kg/d increment, respectively) and for total protein intake in participants younger than 75 years vs 75 years or older (HRs, 0.94 [95% CI, 0.85-1.04] and 0.91 [95% CI, 0.85-0.98] per 0.20-g/kg/d increment in total protein intake, respectively). However, the hazards were lower among participants without CKD than in those with CKD (HRs, 0.85 [95% CI, 0.79-0.92] and 0.92 [95% CI, 0.86-0.98] per 0.20-g/kg/d increment, respectively; P = .02 for interaction). In this multicohort study of older adults, higher intake of total, animal, and plant protein was associated with lower mortality in participants with CKD. Associations were stronger in those without CKD, suggesting that the benefits of proteins may outweigh the downsides in older adults with mild or moderate CKD.

Elucidating the effect of levothyroxine and triiodothyronine on methylglyoxal derived stress.

Methylglyoxal (MG) is the most potent precursor during the formation of the advanced glycation end products (AGEs). MG-dependent glycative stress contributes to pathogenesis of diabetes, age-related disorders, and cancer. There is a great need to study the reduction process of glycative stress for effective management of metabolic disorders. From natural compounds to synthetic drugs, each element contributes to the reduction of glycative stress. Previously, it was established that the lowering of uric acid, low-density lipoprotein cholesterol, and urine albumin excretion rate, as well as reducing total oxidative stress, were all achieved more effectively with a levothyroxine regimen. Still, there is no such study found that supports the MG-dependent glycative stress reduction with thyroid hormone compound. Our study aims to investigate the effects of T3 and T4 on MG-dependent glycative stress. The antiglycation effect was assayed through NBT assay, DNPH assay, ELISA, and fluorescence spectrophotometer. The intracellular reduction in reactive oxygen species (ROS) has been estimated through confocal microscopy. The results revealed an effective reduction in the formation of AGEs adducts and intracellular ROS formation. The investigation concludes AGEs formation was suppressed using these compounds, although in vivo and rigorous clinical trials are required in order to verify these findings.

Sestrin2 knockout exacerbates high-fat diet induced metabolic disorders and complications in female mice

BackgroundObesity and its associated complications raise significant public concern, revealing gender disparities in the susceptibility to metabolic disorders, with females often displaying greater resistance to obesity-related metabolic disorder than males. Sestrin2 is a crucial protein involved in metabolism and energy balance. This study seeks to explore whether Sesn2 knockout (KO) exacerbates high-fat diet (HFD) induced obesity in female mice.MethodsFemale mice with wild-type (WT) and Sesn2 KO were subjected to a 12-week regimen of normal diet or HFD. Using a Body Composition Analyzer, body composition was gauged. Biochemical assays encompassed glucose, lipid, and liver function measurements, alongside 24-hour urine albumin excretion. Echocardiographic evaluation assessed cardiac function. Histopathological analysis of key metabolic tissues (liver, kidney, and heart tissues) were conducted. Western blotting or qRT-PCR evaluated key proteins and genes linked to inflammation, mitochondrial, and lipid metabolism in adipose tissues.ResultsIn comparison to mice fed a regular diet, those on a HFD exhibited significant increases in body weight and fat mass. Notably, Sesn2 KO further aggravated obesity, showcasing the most pronounced metabolic anomalies: elevated body weight, fat mass, impaired glucose tolerance, and insulin sensitivity, alongside heightened levels of free fatty acids and triglycerides. Additionally, KO-HFD mice displayed exacerbated multi-tissue impairments, including elevated hepatic enzymes, increased urinary albumin excretion, compromised cardiac function, and accumulation of lipids in the liver, kidney, and heart. Moreover, adipose tissue showcased altered lipid dynamics and function, characterized by enhanced triglyceride breakdown and modified adipokine levels. Browning was diminished, along with decreased Pgc1α and Sirt1 in KO-HFD mice.ConclusionSesn2 KO exacerbates HFD-induced obesity and metabolic disorders in female mice. These findings underscore Sestrin2’s novel role as a regulator of obesity in female mice.

Coronary microvascular dysfunction and left heart filling pressures in patients with type 2 diabetes.

Patients with type 2 diabetes (T2D) have a high prevalence of diastolic dysfunction and heart failure with preserved ejection fraction (HFpEF), which in turn leads to an increased risk of hospitalization and death. However, the factors of risk and their relative importance in leading to higher left ventricular filling pressures are still disputed. We sought to clarify the associations of a wide range of invasive and non-invasive risk factors with cardiac filling pressures in high-risk T2D patients. Patients with T2D at high risk of cardiovascular events were prospectively enrolled in this study. Participants were thoroughly phenotyped including right heart catheterization at rest and during exercise, echocardiography, urinary excretion of albumin (UACR), and quantification of their myocardial blood flow rate (MFR) using cardiac 82Rb-PET/CT. Of the 37 patients included in the study, 22 (59%) patients met invasive criteria for HFpEF. Only 2 out of 39 variables emerged as independent factors associated with left ventricular filling pressure as assessed by pulmonary capillary wedge pressure (PCWP) at rest; history of hypertension (coefficient: 2.6mmHg [0.3; 5.0], P=0.030) and MFR (P=0.026). We found a significant inverse association between MFR and PCWP with a coefficient of -2.3mmHg (-4.3; -0.3) in PCWP per integer change of MFR. The MFR ranged from 1.18 to 3.68 in our study, which corresponds to a difference in PCWP of approximately 6mmHg between patients with the lowest compared to the highest MFR. During exercise, only 2 variables emerged as borderline independent factors associated with PCWP: myocardial flow reserve (coefficient: -4.4 [-9.6; 0.8], P=0.091) and beta-blockers use (coefficient: 6.1 [-0.1; 12.4], P=0.053). In patients with type 2 diabetes without known HFpEF but risk factors for cardiovascular disease, myocardial blood flow rate was independently associated with PCWP at rest across the range from normal to abnormal left heart filling pressures. A clinically significant difference of 6mmHg in PWCP was attributable to differences in MFR in patients with the lowest compared with the highest MFR values. This suggests that strategies than attenuate microvascular dysfunction could slow progression of increased left ventricular left heart filling pressures in patients at increased risk.

Insulin resistance is associated to future hypertension in normotensive salt-sensitive individuals: a 10-year follow-up study.

Salt-sensitive hypertension is associated with insulin resistance in nonobese individuals. However, no data have been reported for normotensive offspring of hypertensive salt-sensitive parents. To evaluate in normotensive salt-sensitive or salt-resistant offspring of hypertensive parents (offSS-HT and offSR-HT, respectively): the possible association between insulin resistance and endothelial dysfunction, and the risk of developing hypertension in a 10-year follow-up. Forty-one offSS-HT (29 ± 2 years; 20 female) and 36 offSR-HT (25 ± 3 years; 16 female) were followed up for 10 years. Both groups were considered lean. At baseline, creatinine clearance (CrCl), 24 h urinary albumin excretion (UAE), glycemia, and insulinemia were measured before and after 60 and 120 min of glucose overload (75 g). HOMA Index and the area under the curve (AUC) were calculated. Blood pressure (BP) and 24 h urine sodium excretion was measured annually. Postischemic minimum vascular resistance (forearm plethysmography) was assessed at baseline. In offSS-HT, UAE (53 ± 3 mg/min) and CrCl (136 ± 8 ml/min) were higher in offSS-HT than in offSR-HT. (UAE: 12 ± 4 mg.min; p,0.01 and CrCl 107 ± 6 ml.min; P < 0.01). An impaired vasodilatory postischemic response was observed in offSS-HT compared with offSR-HT ( P < 0.01). In offSS-HT glycemia, insulin, AUC at 69 and 120 min post OTG were greater than in offSR-HT, p < 0.02. In offSS-HT, blood pressure rose ( P < 0.01) the 10 years follow-up compared with offSR-HT. Salt sensitivity in the offspring of hypertensive salt-sensitive individuals is associated with insulin resistance and endothelial dysfunction and is prone to hypertension over a short period of time.

Caloric and time restriction diets improve acute kidney injury in experimental menopausal rats: role of silent information regulator 2 homolog 1 and transforming growth factor beta 1.

Estrogen has a protective impact on acute kidney injury (AKI); moreover, reducing the daily intake of calories impedes developing diseases. The present study aimed to determine the effects of calorie restriction (CR) and time restriction (TR) diets on the expression of silent information regulator 2 homolog 1 (SIRT1), transforming growth factor beta 1 (TGF-β1), and other indicators in the presence and absence of ovaries in AKI female rats. The female rats were divided into two groups, ovariectomized (OVX) and sham, and were placed on CR and TR diets for eight weeks; afterward, AKI was induced by injecting glycerol, and kidney injury indicators and biochemical parameters were measured before and after AKI. After AKI, the levels of urine albumin excretion rate, urea, and creatinine in serum, and TGF-β1 increased, while creatinine clearance and SIRT1 decreased in kidney tissue. CR improved kidney indicators and caused a reduction in TGF-β1 and an increase in SIRT1 in ovary-intact rats. Moreover, CR prevented total antioxidant capacity (TAC) decrease and malondialdehyde (MDA) increase resulting from AKI. Before AKI, an increase in body weight, fasting blood sugar (FBS), low-density lipoprotein (LDL), triglyceride (TG), and total cholesterol (TC), and a decrease in high-density lipoprotein (HDL) were observed in OVX rats compared to sham rats, but CR prevented these changes. The effects of TR were similar to those of CR in all indicators except for TGF-β1, SIRT1, urea, creatinine, and albumin. The present study indicated that CR is more effective than TR in preventing AKI, probably by increasing SIRT1 and decreasing TGF-β1 in ovary-intact animals.