Reduced GFR and albuminuria in Chinese type 2 diabetes mellitus patients are both independently associated with activation of the TNF-alpha system

Circulating tumor necrosis factor-related biomarkers predict kidney function decline in Japanese patients with diabetes: An observational cohort study

AIMS

Tumor necrosis factor (TNF) receptors (TNFRs: TNFR1 and, TNFR2) are reportedly associated with chronic kidney disease (CKD) progression chiefly in Caucasian patients with diabetes. We assessed the prognostic value of TNF-related biomarkers for CKD progression in Japanese patients with diabetes.

METHODS

We estimated TNF-related biomarkers using an enzyme-linked immunosorbent assay in 640 patients with diabetes. Cox proportional hazards analysis was performed to estimate hazard ratios (HRs) per one standard deviation (SD) increase in a log-transformed biomarker. The kidney and the composite outcome were defined as a 30% reduction in estimated glomerular filtration rate (eGFR) from baseline, and kidney outcome plus death before kidney outcome, respectively.

RESULTS

During the median follow-up of 5.4 years, 75 (11.7%) patients reached the kidney outcome and 37 (5.8%) died before reaching the kidney outcome. Each SD increase in baseline circulating TNFR1, TNFR2, and ephrin type-A receptor 2 (EphA2) was associated with a higher risk of the kidney outcome independently from baseline eGFR and urine albumin-to-creatinine ratio. However, circulating osteoprotegerin was associated with the composite outcome only.

CONCLUSIONS

Elevated TNFR1, TNFR2, and EphA2 were associated with both kidney and composite outcomes in Japanese patients with diabetes.

Biomarkers of Inflammation and Glomerular Filtration Rate in Individuals with Recent-Onset Type 1 and Type 2 Diabetes

CONTEXT

While inflammation has been associated with kidney function in long-standing diabetes, its possible association in newly diagnosed diabetes is unknown.

OBJECTIVE

To investigate cross-sectional and prospective associations between biomarkers of inflammation and kidney function in recent-onset diabetes.

METHODS

The study included individuals with type 1 and type 2 diabetes with known diabetes duration of <1 year from the German Diabetes Study. Baseline serum concentrations of 74 biomarkers were measured using proximity extension assay technology and their associations with estimated glomerular filtration rate (eGFR) and kidney function decline over 5 years were tested using multiple linear and logistic regression analysis.

RESULTS

The cross-sectional analysis included 165 individuals with type 1 diabetes and 291 with type 2 diabetes. Baseline eGFR was higher in type 1 compared with type 2 diabetes (102 ± 15 vs 90 ± 16 mL/min/1.73 m2; P < 0.0001). After full adjustment for covariates and multiple testing, 7 biomarkers were associated with lower baseline eGFR in type 1 diabetes and 24 were associated with lower baseline eGFR in type 2 diabetes. Among these biomarkers, 6 biomarkers (CD5, CCL23, CST5, IL-10RB, PD-L1, TNFRSF9) were inversely associated with eGFR in both diabetes types. The prospective analysis did not detect associations between inflammatory biomarkers and kidney function decline. No evidence of an interaction between diabetes type and inflammatory biomarkers was found.

CONCLUSION

Several biomarkers of inflammation associate with lower baseline eGFR in recent-onset type 1 and type 2 diabetes, but do not associate with kidney function loss during the first 5 years after the diagnosis of diabetes.

Cohort profile: the Singapore diabetic cohort study

PURPOSE

The diabetic cohort (DC) was set up to study the determinants of complications in individuals with type 2 diabetes and examine the role of genetic, physiological and lifestyle factors in the development of complications in these individuals.

PARTICIPANTS

A total of 14 033 adult participants with type 2 diabetes were recruited from multiple public sector polyclinics and hospital outpatient clinics in Singapore between November 2004 and November 2010. The first round of follow-up was conducted for 4131 participants between 2012 and 2016; the second round of follow-up started in 2016 and is expected to end in 2021. A questionnaire survey, physical assessments, blood and urine sample collection were conducted at recruitment and each follow-up visit. The data set also includes genetic data and linkage to medical and administrative records for recruited participants.

FINDINGS TO DATE

Data from the cohort have been used to identify determinants of diabetes and related complications. The longitudinal data of medical records have been used to analyse diabetes control over time and its related outcomes. The cohort has also contributed to the identification of genetic loci associated with type 2 diabetes and diabetic kidney disease in collaboration with other large cohort studies. About 25 scientific papers based on the DC data have been published up to May 2019.

FUTURE PLANS

The rich data in DC can be used for various types of research to study disease-related complications in patients with type 2 diabetes. We plan to further investigate disease progression and new biomarkers for common diabetic complications, including diabetic kidney disease and diabetic neuropathy.

Circulating TNF Receptors 1 and 2 Predict Mortality in Patients with End-stage Renal Disease Undergoing Dialysis

Relatively high circulating levels of soluble tumor necrosis factor (TNF) receptors (TNFRs: TNFR1, TNFR2) have been associated with not only progression to end-stage renal disease but also mortality in patients with diabetes. It remains unknown whether elevated TNFR levels in haemodialysis patients are associated with mortality. We studied 319 patients receiving maintenance haemodialysis who were followed for a median of 53 months. Circulating markers of TNF pathway (TNFα and TNFRs) were measured with immunoassay. Strong positive correlations between TNFR1 and TNFR2 were observed (r = 0.81, P < 0.0001). During follow-up, 88 (27.6%) patients died of any cause (40 [45.5%] died of cardiovascular disease). In the Cox multivariate model, either TNFR but not TNFα remained a significant independent predictor of all-cause mortality (TNFR1: hazard ratio [HR] 2.34, 95% confidence interval [CI], 1.50–3.64; TNFR2: HR 2.13, 95% CI 1.38–3.29) after adjustment for age, prior cardiovascular disease, predialysis systolic blood pressure, and large systolic blood pressure decline during dialysis session. For cardiovascular mortality, significance was only observed in TNFR1 (TNFR1: HR 2.15, 95% CI 1.13–4.10). Elevated TNFRs levels were associated with the risk of cardiovascular and/or all-cause mortality independent of all relevant covariates in patients undergoing haemodialysis.

Association of Circulating Biomarkers (Adrenomedullin, TNFR1, and NT-proBNP) With Renal Function Decline in Patients With Type 2 Diabetes: A French Prospective Cohort

OBJECTIVE

We explored the prognostic value of three circulating candidate biomarkers-midregional-proadrenomedullin (MR-proADM), soluble tumor necrosis factor receptor 1 (sTNFR1), and N-terminal prohormone brain natriuretic peptide (NT-proBNP)-for change in renal function in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Outcomes were defined as renal function loss (RFL), ≥40% decline of estimated glomerular filtration rate (eGFR) from baseline, and rapid renal function decline (RRFD), absolute annual eGFR slope <-5 mL/min/year. We used a proportional hazard model for RFL and a logistic model for RRFD. Adjustments were performed for established risk factors (age, sex, diabetes duration, HbA_1c, blood pressure, baseline eGFR, and urinary albumin-to-creatinine ratio [uACR]). C-statistics were used to assess the incremental predictive value of the biomarkers to these risk factors.

RESULTS

Among 1,135 participants (mean eGFR 76 mL/min, median uACR 2.6 mg/mmol, and median GFR slope -1.6 mL/min/year), RFL occurred in 397, RRFD developed in 233, and 292 died during follow-up. Each biomarker predicted RFL and RRFD. When combined, MR-proADM, sTNFR1, and NT-proBNP predicted RFL independently from the established risk factors (adjusted hazard ratio 1.59 [95% CI 1.34-1.89], P < 0.0001; 1.33 [1.14-1.55], P = 0.0003; and 1.22 [1.07-1.40], P = 0.004, respectively) and RRFD (adjusted odds ratio 1.56 [95% CI 1.7-2.09], P = 0.003; 1.72 [1.33-2.22], P < 0.0001; and 1.28 [1.03-1.59], P = 0.02, respectively). The combination of the three biomarkers yielded the highest discrimination (difference in C-statistic = 0.054, P < 0.0001; 0.067, P < 0.0001 for RFL; and 0.027, P < 0.0001 for RRFD).

CONCLUSIONS

In addition to established risk factors, MR-proADM, sTNFR1, and NT-proBNP improve risk prediction of loss of renal function in patients with type 2 diabetes.

Tumor necrosis factor receptors 1 and 2 are associated with early glomerular lesions in type 2 diabetes

Elevated serum tumor necrosis factor receptor 1 (TNFR1) and 2 (TNFR2) concentrations are strongly associated with increased risk of end-stage renal disease in type 2 diabetes. However, little is known about the early glomerular structural lesions that develop in patients when these markers are elevated. Here we examined the relationships between TNFRs and glomerular structure in 83 American Indians with type 2 diabetes. Serum TNFRs and glomerular filtration rates (GFR, iothalamate) were measured during a research exam performed within a median of 0.9 months from a percutaneous kidney biopsy. Associations of TNFRs with glomerular structural variables were quantified by Spearman's correlations and by multivariable linear regression after adjustment for age, gender, diabetes duration, hemoglobin A1c, body mass index, and mean arterial pressure. The baseline mean age was 46 years, median GFR 130 ml/min, median albumin/creatinine ratio 26 mg/g, median TNFR1 1500 pg/ml, and median TNFR2 3284 pg/ml. After multivariable adjustment, TNFR1 and TNFR2 significantly correlated inversely with the percentage of endothelial cell fenestration and the total filtration surface per glomerulus. There were significant positive correlations with mesangial fractional volume glomerular basement membrane width, podocyte foot process width, and percent of global glomerular sclerosis. Thus, TNFRs may be involved in the pathogenesis of early glomerular lesions in diabetic nephropathy.

Circulating TNF receptors 1 and 2 are associated with the severity of renal interstitial fibrosis in IgA nephropathy

The current study aimed to examine whether the levels of TNF receptors 1 and 2 (TNFR1 and TNFR2) in serum and urine were associated with other markers of kidney injury and renal histological findings, including TNFR expression, in IgA nephropathy (IgAN). The levels of the parameters of interest were measured by immunoassay in 106 biopsy-proven IgAN patients using samples obtained immediately before renal biopsy and in 34 healthy subjects. Renal histological findings were evaluated using immunohistochemistry. The levels of serum TNFRs were higher in IgAN patients than in healthy subjects. The levels of both TNFRs in serum or urine were strongly correlated with each other (r > 0.9). Serum TNFR levels were positively correlated with the urinary protein to creatinine ratio (UPCR) and four markers of tubular damage of interest (N-acetyl-β-D-glucosaminidase [NAG], β2 microglobulin [β2m], liver-type fatty acid-binding protein [L-FABP], and kidney injury molecule-1 [KIM-1]) and negatively correlated with estimated glomerular filtration rate (eGFR). Patients in the highest tertile of serum TNFR levels showed more severe renal interstitial fibrosis than did those in the lowest or second tertiles. The tubulointerstitial TNFR2-, but not TNFR1-, positive area was significantly correlated with the serum levels of TNFRs and eGFR. Stepwise multiple regression analysis revealed that elevated serum TNFR1 or TNFR2 levels were a significant determinant of renal interstitial fibrosis after adjusting for eGFR, UPCR, and other markers of tubular damage. In conclusion, elevated serum TNFR levels were significantly associated with the severity of renal interstitial fibrosis in IgAN patients. However, the source of TNFRs in serum and urine remains unclear.

Circulating TNF receptor 2 is closely associated with the kidney function in non-diabetic Japanese subjects

AIM

Chronic kidney disease (CKD) is associated with cardiovascular events. Tumor necrosis factor (TNF) and/or its receptors have been postulated to be involved in renal pathophysiology. It is unclear whether an increased TNF system activity is present before the development of apparent CKD.

METHODS

Four hundred and twenty non-diabetic Japanese subjects with an estimated GFR (eGFR) greater than 60 ml/min/1.73 m(2) were recruited for measurement of the HbA1c, insulin, TNF system activity (TNF-α, soluble TNF receptor 1 (sTNF-R1) and sTNF-R2) levels and various parameters, including the lipid, high-sensitivity C-reactive protein (hsCRP), high-molecular-weight (HMW) adiponectin and leptin levels. The subjects were stratified according to the eGFR: the G1 level (eGFR ≧90 ml/min/1.73 m(2)) and the G2 level (90 ＞eGFR ≧60 ml/min/1.73 m(2)).

RESULTS

Whereas no significant differences were observed in gender, body mass index (BMI), blood pressure, insulin, TNF-α, hsCRP, HMW adiponectin or leptin between the two groups, the values for age, HbA1c, triglycerides, sTNF-R1 and sTNF-R2 were significantly higher in the subjects with a G2 level of eGFR than in those with a G1 level. In contrast, the HDL cholesterol levels were significantly lower in the subjects with a G2 level than in those with a G1 level. Linear negative correlations were also observed between eGFR and age, BMI, HbA1c, triglycerides, sTNF-R1 and sTNFR2, respectively. A multiple logistic regression analysis revealed that only sTNF-R2 was associated with the presence of a G2 level of eGFR (Odds ratio 1.092, 95% CI 1.013-1.177, P=0.021).

CONCLUSIONS

The circulating sTNF-R2 level is closely associated with the kidney function in non-diabetic Japanese subjects.

Novel biomarkers for the progression of diabetic nephropathy: soluble TNF receptors

Despite 2 decades of advances in therapy of diabetic patients, the prevalence of diabetic nephropathy among patients with diabetes has not decreased. However, large-scale multicenter studies have achieved great success in terms of the reduction of albuminuria, suggesting that albuminuria might not be an accurate surrogate marker for slowing the rate of renal function decline. It is important to be able to identify individuals at high risk for renal function decline, or ultimately, end-stage kidney disease (ESKD) and its associated cardiovascular disease (CVD). More sensitive early biomarkers, other than albuminuria and the estimated glomerular filtration rate (eGFR), should be required. Recently, serum concentrations of soluble tumor necrosis factor (TNF), receptor 1 (TNFR1), and TNFR2 have predicted future GFR loss and ESKD in patients of a wide variety of stages and both types of diabetes. Longitudinal interventional studies are needed to validate these biomarkers in a broad range of populations prior to implementation in routine diabetes management.

Structural damage in diabetic nephropathy is associated with TNF-α system activity

In experimental animal studies, tumour necrosis factor-α (TNF-α) contributed to renal hypertrophy during diabetes, and antibodies against TNF-α have led to improved histological lesions in animals with nephrotoxicity and diabetic nephropathy. We aimed to evaluate TNF-α system activity in association with renal histology in patients with type 2 diabetes. This is a prospective, cross-sectional study of 22 patients with type 2 diabetes (16 men), 13 with microalbuminuria and 9 with normoalbuminuria. Plasma-soluble TNF-α receptor 1 and 2 (sTNFR1 and sTNFR2) concentrations were used as surrogates of TNF-α system activity. Glomerular filtration rate (GFR) was analysed using I(125)-Iodothalamine. Albumin excretion rate (AER) and a renal biopsy were performed in all subjects. AER did not associate significantly with mesangial expansion or interstitial fraction in these subjects (r < 0.12, P > 0.5). AER was also not associated with either sTNFR1 or sTNFR2 levels. However, after controlling for GFR, the correlation between AER and sTNFR1 became significant (r = 0.47, P = 0.03). sTNFR1 correlated with age (r = 0.65, P < 0.001), mesangial expansion (r = 0.59, P = 0.004) and interstitial fraction (r = 0.58, P = 0.005). After controlling for age, body mass index and blood pressure, the association of TNFR1 with mesangial expansion persisted significant. Circulating sTNFR2 concentrations were not significantly associated with histological changes. In summary, structural kidney damage in patients with type 2 diabetes is associated with TNF-α system activity and specifically with plasma sTNFR1 concentrations.

Association between serum soluble TNFα receptors and renal dysfunction in type 2 diabetic patients without proteinuria

AIM

The aim of our study was to investigate whether serum levels of soluble tumor necrosis factor α receptor (sTNFR) 1 and 2 are markers for renal dysfunction in type 2 diabetic patients without overt proteinuria.

METHODS

Japanese type 2 diabetic patients without overt proteinuria (n = 168) enrolled in the prospective observational follow-up study in 2001 were retrospectively analyzed. At baseline, the serum levels of sTNFR1 and sTNFR2 were measured by sandwich ELISA. The associations between these markers and change in estimated glomerular filtration rate (eGFR) after 5 years were evaluated.

RESULTS

The levels of sTNFR1 and sTNFR2 closely correlated. At baseline, sTNFR1 and sTNFR2 associated inversely with eGFR. After 5 years, patients with high level of both sTNFR1 and sTNFR2 showed a greater decline in eGFR (-13.8 ± 15.5% versus -8.5 ± 11.8%, P = 0.027) and a 4-fold higher risk for a GFR decline of ≥ 25% than those with high level of only one receptor or low level of both receptors. These associations were enhanced in diabetic women.

CONCLUSIONS

The higher levels of sTNFR1 and sTNFR2 were associated with a greater decline in eGFR in type 2 diabetic patients without proteinuria, especially in diabetic women.

Nephrinuria associates with multiple renal traits in type 2 diabetes

BACKGROUND

The involvement of nephrin in controlling renal function is unclear with the literature only emphasizing its role in albuminuria. We therefore investigated the potential association between nephrinuria as evidenced by the appearance of urinary immunopositive nephrin fragments, with multiple renal traits.

METHODS

Western blot analysis of the urine samples from a cross-sectional study of 381 Chinese type 2 diabetic patients revealed four distinct protein fragments, indicative of nephrinuria. Albuminuria was measured in random spot urine samples using the albumin/creatinine ratio (ACR), while estimated glomerular filtration rate (eGFR) was calculated using the creatinine-based Modification of Diet in Renal Disease formula.

RESULTS

Each nephrin fragment was associated with a decline in eGFR (smallest P = 0.001). Even with the inclusion of logarithmic form of ACR (ln ACR) in the multivariate model, nephrinuria still remained significantly associated with lower eGFR (smallest P < 0.05). Nephrinuria was also strongly associated with lnACR and this finding was independent of eGFR (smallest P < 0.001). Thus, nephrinuria was independently associated with both renal traits in the form of lnACR and eGFR. Furthermore, nephrinuria was significantly associated with lower eGFR even among normoalbuminuric patients (ACR ≤ 30 mg/g) (smallest P = 0.002), potentially implicating nephrinuria in the development of normoalbuminuric renal insufficiency. Apart from the renal traits under investigation, the presence of nephrinuria did not associate with other patient clinical characteristics.

CONCLUSIONS

Nephrinuria was associated with multiple renal traits in type 2 diabetes even in normoalbuminuric patients who are traditionally perceived as having a low risk of chronic kidney disease.

A single nucleotide polymorphism within the acetyl-coenzyme A carboxylase beta gene is associated with proteinuria in patients with type 2 diabetes

It has been suggested that genetic susceptibility plays an important role in the pathogenesis of diabetic nephropathy. A large-scale genotyping analysis of gene-based single nucleotide polymorphisms (SNPs) in Japanese patients with type 2 diabetes identified the gene encoding acetyl-coenzyme A carboxylase beta (ACACB) as a candidate for a susceptibility to diabetic nephropathy; the landmark SNP was found in the intron 18 of ACACB (rs2268388: intron 18 +4139 C > T, p = 1.4x10(-6), odds ratio = 1.61, 95% confidence interval [CI]: 1.33-1.96). The association of this SNP with diabetic nephropathy was examined in 9 independent studies (4 from Japan including the original study, one Singaporean, one Korean, and two European) with type 2 diabetes. One case-control study involving European patients with type 1 diabetes was included. The frequency of the T allele for SNP rs2268388 was consistently higher among patients with type 2 diabetes and proteinuria. A meta-analysis revealed that rs2268388 was significantly associated with proteinuria in Japanese patients with type 2 diabetes (p = 5.35 x 10(-8), odds ratio = 1.61, 95% Cl: 1.35-1.91). Rs2268388 was also associated with type 2 diabetes-associated end-stage renal disease (ESRD) in European Americans (p = 6 x 10(-4), odds ratio = 1.61, 95% Cl: 1.22-2.13). Significant association was not detected between this SNP and nephropathy in those with type 1 diabetes. A subsequent in vitro functional analysis revealed that a 29-bp DNA fragment, including rs2268388, had significant enhancer activity in cultured human renal proximal tubular epithelial cells. Fragments corresponding to the disease susceptibility allele (T) had higher enhancer activity than those of the major allele. These results suggest that ACACB is a strong candidate for conferring susceptibility for proteinuria in patients with type 2 diabetes.