Arteriolar Hyalinosis Predicts the Onset of Both Macroalbuminuria and Impaired Renal Function in Patients with Type 2 Diabetes.

INTRODUCTION: Arteriolar hyalinosis (AH) has been shown to be associated with albuminuria and GFR. In this study, we investigated whether or not index of AH (IAH) is a predictor of the onset of macroalbuminuria and impaired renal function (eGFR <60 mL/min/1.73 m2 [eGFR <60]) in type 2 diabetic patients with early diabetic nephropathy. METHODS: The study population consisted of 35 patients with type 2 diabetes (25 men; age: 47 ± 9 years; eGFR: 92.7 ± 18.0 mL/min/1.73 m2) with normo- or microalbuminuria who underwent percutaneous renal biopsy. These patients were followed for at least 5 (18 ± 6, range: 6-28) years. The study endpoint was the onset of macroalbuminuria or eGFR <60. Light and electron microscopy-based morphometric analyses were performed to quantitatively evaluate glomerular and interstitial structural changes. RESULTS: During the observation period, 9 out of the 35 patients progressed to macroalbuminuria, and 15 out of the 35 patients developed eGFR <60. The annual rate of eGFR decline was significantly correlated with IAH (r = -0.40, p = 0.016). Kaplan-Meier analysis demonstrated that AH was associated with a significantly higher risk of onset of macroalbuminuria and eGFR <60, and microalbuminuria is associated with the onset of macroalbuminuria but not the onset of eGFR <60. CONCLUSIONS: Aggravated AH is a histological risk factor which predicts the onset of macroalbuminuria and eGFR <60 in patients with type 2 diabetes. These findings provide novel insights into the mechanism of progression of diabetic nephropathy.

Lost in translation: assessing the nomenclature change for diabetic kidney disease in Japan.

Recently in Japan, the term "tonyobyo sei jinzobyo", the Japanese translation of "diabetic kidney disease", has been increasingly used in place of the term "tonyobyo sei jinsho", the Japanese translation of "diabetic nephropathy". Many international diabetes and nephrology guidelines have defined diabetic kidney disease as a condition caused by diabetes, typically presenting with albuminuria, similar to or identical to current and historical definitions for diabetic nephropathy. However, recent guidelines from the Japanese Society of Nephrology propose a broader disease concept for the term diabetic kidney disease, including patients without albuminuria. A rationale for proposing a broader disease concept for diabetic kidney disease may have come from changes in the kidney phenotype of patients with diabetes observed in recent years. Epidemiological studies have shown that an increasing proportion of patients with diabetes have reduced kidney function, while the prevalence of those with albuminuria appears to have decreased. However, these studies also suggested that the more advanced age of patients presenting with diabetes and increased use of renin-angiotensin system blockers may have contributed to this change in disease phenotype. We believe the principal rationale for the nomenclature change from diabetic nephropathy to diabetic kidney disease was to create a more easily understood, lay-language term for English speakers, rather than to create a term to encompass a broader population of diabetes with chronic kidney disease (CKD). Further discussion and international consensus are needed for the definition of diabetic kidney disease, to avoid ambiguity or possible confusion.

Risk of fetal undergrowth in the management of gestational diabetes mellitus in Japan.

AIMS/INTRODUCTION: In Japan, the increasing frequency of underweight among women of reproductive age and the accompanying increase in the rate of low birth weight (LBW) are social issues. The study aimed to establish a prospective registry system for gestational diabetes mellitus (GDM) in Japan and to clarify the actual status of GDM according to the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria. MATERIALS AND METHODS: Pregnant women with gestational diabetes mellitus and those in the normal glucose tolerance (NGT) group were enrolled in the Diabetes and Pregnancy Outcome for Mother and Baby study from October 2015. Pregnant women with positive glucose screening in early and mid-to-late pregnancy underwent a 75 g oral glucose tolerance test by gestational week 32. Gestational diabetes mellitus was diagnosed according to IADPSG criteria. Women with a positive glucose screening test at mid-to-late pregnancy but NGT were enrolled as references (NGT group). Treatment for gestational diabetes mellitus and maternal and neonatal pregnancy data were prospectively collected on outcomes. RESULTS: In total 1,795 singleton pregnancies (878 women with GDM and 824 NGT women) were analyzed. The risk of LBW and small-for-gestational age in the GDM group was significantly higher than in the NGT group. A similar relationship was found for LBW risk in the non-overweight/obese group but not in the overweight/obese group. CONCLUSIONS: We established a prospective GDM registry system in Japan. In the management of GDM in Japan, suppression of maternal weight gain may be associated with reduced fetal growth, especially in non-overweight/obese women with GDM; however, further investigation is required.

Sex differences in risk factors for end-stage kidney disease and death in type 2 diabetes: A retrospective cohort study.

BACKGROUND: This study investigated the sex differences in the risk of end-stage kidney disease (ESKD) and mortality, as well as the effect modification of sex on associated factors in patients with type 2 diabetes. METHODS: This multicenter observational cohort study included 4328 patients with type 2 diabetes. Hazard ratios (HRs) with 95% confidence intervals (CIs) of sex for ESKD and death were estimated using Cox proportional regression with adjustment for baseline covariates. For assessing risk modification, HRs and incidence rates for ESKD and death were compared between sexes across patient characteristics using Cox proportional and Poisson regression models. RESULTS: During a median follow-up of 7 years, 276 patients (70% men) developed ESKD, and 241 patients (68% men) died. Men had higher risks of ESKD (HR 1.34; 95% CI 1.02-1.75; p = .034) and death (HR 1.64; 95% CI 1.24-2.16; p = .001) versus women after adjusting for multiple covariates. Among patients with microalbuminuria, men had a substantially higher risk of ESKD versus women, compared to those with normo- and macroalbuminuria (p for interaction .04). Incidence rates were also increased in men versus women with albuminuria of around 300 mg/g. No differences were detected in the association of sex and death across baseline patient subgroups. CONCLUSIONS: In type 2 diabetes, men had an increased risk of ESKD and death versus women. Moderately increased albuminuria was strongly associated with sex difference in developing ESKD.

Pre-Vaccination Anti-Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Seroprevalence in Workers at Three Japanese Hospitals.

BACKGROUND: Antibody testing is essential for accurately estimating the number of people infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study aimed to investigate the influence of background factors on seroprevalence by testing for anti-SARS-CoV-2 antibodies in blood samples obtained from the staff of three hospitals. METHODS: This cross-sectional observational study was conducted from June 8 to July 4, 2020, as part of a mandatory health examination. Leftover blood samples collected during the health examinations at each hospital were used to test for the presence of anti-SARS-CoV-2 antibodies. The Elecsys Anti-SARS-CoV-2 RUO assay was used for antibody detection. The relationship between staff age, gender, body mass index, blood pressure, work environments with different exposure risks, place of residence, and campus location and seroprevalence was investigated. The data were anonymized prior to analysis. RESULTS: A total of 3,677 individuals were included in the study, comprising 2,554 females (69.5%) and 1,123 males (30.5%). Anti-SARS-CoV-2 antibody (immunoglobulin G) was detected in 13 participants (0.35%). Seroprevalence was slightly higher in males than females (0.62% vs. 0.23%, P=0.08). By occupation, anti-SARS-CoV-2 antibodies were found in 6 (0.75%) physicians, 6 (0.31%) nurses, and one individual (0.11%) in the medical personnel group, with slightly higher levels in physicians. No significant difference was noted in the seroprevalence in terms of all background factors. CONCLUSIONS: Our study shows that the background factors do not impact seropositivity rates. Thorough daily infection control and adherence to recommended health guidelines were found to reduce infection risk.

Glucose control, diabetic retinopathy, and hemodialysis induction in subjects with normo-microalbuminuric type 2 diabetic patients with normal renal function followed for 15 years.

AIMS: A high urinary albumin excretion (UAE) and low glomerular filtration rate (GFR) are risk factors for progressive renal function loss in type 2 diabetic patients. In addition, diabetic retinopathy (DR) is also a risk factor for progressive renal function decline in microalbuminuric type 2 diabetic patients. We aimed to elucidate the factors, including DR, associated with a more severe situation of diabetic nephropathy, i.e., hemodialysis (HD) induction in normo- and microalbuminuric type 2 diabetic patients without renal dysfunction. METHODS: Normo- and microalbuminuric type 2 diabetic patients with normal renal function whose GFRs had been measured by iohexol injection in 1995-1997 and had been followed for over 5 years were analyzed (n = 199). HbA1c levels was divided into HbA1c ≥ 7.0 (n = 146) and <7.0 (n = 53) groups. The UAE levels were classified as normoalbuminuria (NA, n = 114) and microalbuminuria (MA, n = 85). Seventy-two patients had DR, and 96 had hypertension. Patients were followed up for 15.7 ± 6.0 years and frequency of and duration to the HD induction were evaluated. RESULTS: During the study period, 8 patients received HD induction. There were no remarkable differences in the rates of HD induction between patients with and without HbA1c ≥7.0, microalbuminuria, DR or hypertension. A Kaplan-Meier analysis revealed that HbA1c ≥7.0 (p = 0.037) and DR (p = 0.037) were associated with a significantly higher risk of HD induction than HbA1c <7.0 and no DR, respectively while albuminuria grade and hypertension were not associated with the risk of HD induction. There was significant negative correlation between HbA1c and annual decline rate of eGFR and annual decline rate of eGFR in the patients with prepro-proliferative DR (PDR) was significantly higher than that in the patients without DR. In the multivariate analysis, HbA1c and PDR showed significant relationships with the annual decline rate of eGFR. CONCLUSIONS: It was reasonable that poorer glycemic control affected HD induction for 16 years follow-up. However, DR, especially PDR, should also be considered a substantial risk factor for HD induction although microalbuminuria and hypertension did not predict it at the early stage of diabetic nephropathy in type 2 diabetic patients with normal renal function.

Developing a health economic model for Asians with type 2 diabetes based on the Japan Diabetes Complications Study and the Japanese Elderly Diabetes Intervention Trial.

INTRODUCTION: Cost-effectiveness analyses are becoming increasingly important in Japan following the introduction of a health technology assessment scheme. The study objective was to develop an economic model to evaluate the cost-effectiveness of two interventions for type 2 diabetes in a Japanese population. RESEARCH DESIGN AND METHODS: The Japan Diabetes Complications Study/Japanese Elderly Diabetes Intervention Trial risk engine (JJRE) Cost-Effectiveness Model (JJCEM) was developed, incorporating validated risk equations in Japanese patients with type 2 diabetes from the JJRE. Weibull regression models were developed for progression of the model outcomes, and a targeted literature review was performed to inform default values for utilities and costs. To illustrate outcomes, two simulated analyses were performed in younger (aged 40 years) and older (aged 80 years) Japanese populations, comparing a hypothetical treatment with placebo. RESULTS: The model considers a population based on user-defined values for 11 baseline characteristic parameters and simulates rates of diabetic complications over a defined time horizon. Costs, quality-adjusted life years, and an incremental cost-effectiveness ratio are estimated. The model provides disaggregated results for two competing interventions, allowing visualization of the key drivers of cost and utility. A scatterplot of simulations and cost-effectiveness acceptability curve are generated for each analysis. CONCLUSIONS: This is the first cost-effectiveness model for East Asian patients with type 2 diabetes, developed using Japan-specific risk equations. This population constitutes the largest share of the global population with diabetes, making this model highly relevant. The model can be used to evaluate the cost-effectiveness of anti-diabetic interventions in patients with type 2 diabetes in Japan and other East Asian populations.

Combined changes in albuminuria and kidney function and subsequent risk for kidney failure in type 2 diabetes.

INTRODUCTION: Changes in albuminuria or estimated glomerular filtration rate (eGFR) can be used as a surrogate endpoint of end-stage kidney disease (ESKD) in people with type 2 diabetes. We investigated whether the combined changes in albuminuria and eGFR are more strongly associated with future risk of ESKD. RESEARCH DESIGN AND METHODS: Using data from a multicenter observational cohort study of people with type 2 diabetes, we evaluated the association of percentage change in urine albumin to creatinine ratio (UACR) and/or annual change in eGFR over 2 years with subsequent ESKD risk. RESULTS: Among 1417 patients with repeated albuminuria and eGFR over 2 years, 129 (9.1%) developed ESKD. Patients with >30% UACR decline had lower ESKD risk (HR 0.47; 95% CI 0.29 to 0.77), whereas those with >30% UACR increase had higher ESKD risk (HR 2.31; 95% CI 1.52 to 3.51), compared with those with minor UACR change. Patients with greater eGFR decline had an increased ESKD risk than those with minor eGFR change (a decline of <2.5 mL/min/1.73 m2/year): HR 4.19 (95% CI 1.87 to 9.38) and 2.89 (95% CI 1.32 to 6.33) for those with a decline of >5 and 2.5-5 mL/min/1.73 m2/year, respectively. When the combined changes in UACR and eGFR were used, the highest ESKD risk (HR 5.60; 95% CI 2.08 to 15.09) was observed among patients with >30% UACR increase and an eGFR decline of >5 mL/min/1.73 m2/year compared with those with a minor change in UACR and eGFR. CONCLUSIONS: Combined changes in albuminuria and eGFR over 2 years were strongly associated with future risk of kidney failure in patients with type 2 diabetes.

Sodium Intake and Incidence of Diabetes Complications in Elderly Patients with Type 2 Diabetes-Analysis of Data from the Japanese Elderly Diabetes Intervention Study (J-EDIT).

This study investigates the associations between sodium intake and diabetes complications in a nationwide cohort of elderly Japanese patients with type 2 diabetes aged 65-85. Data from 912 individuals regarding their dietary intake at baseline is analyzed and assessed by the Food Frequency Questionnaire based on food groups. Primary outcomes are times to diabetic retinopathy, overt nephropathy, cardiovascular disease (CVD), and all-cause mortality during six years. We find that mean sodium intake in quartiles ranges from 2.5 g to 5.9 g/day. After adjustment for confounders, no significant associations are observed between sodium intake quartiles and incidence of diabetes complications and mortality, except for a significant trend for an increased risk of diabetic retinopathy (p = 0.039). Among patients whose vegetable intake was less than the average of 268.7 g, hazard ratios (HRs) for diabetic retinopathy in patients in the second, third, and fourth quartiles of sodium intake compared with the first quartile were 0.87 (95% CI, 0.31-2.41), 2.61 (1.00-6.83), and 3.70 (1.37-10.02), respectively. Findings indicate that high sodium intake under conditions of low vegetable intake is associated with an elevated incidence of diabetic retinopathy in elderly patients with type 2 diabetes.

Arteriolar hyalinosis is related to rapid GFR decline and long-standing GFR changes observed on renal biopsies in normo-microalbuminuric type 2 diabetic patients.

AIMS: Whether or not renal structural changes, especially arteriolar hyalinosis, are related to the rate of renal functional decline and increase in urinary albumin excretion (UAE) at the early stage of diabetic nephropathy in patients with type 2 diabetes is still unknown. Our previous study determined that arteriolar hyalinosis is an independent risk factor for low GFR. We sought to determine whether arteriolar hyalinosis is also a risk factor for rapidly progressive decline in GFR. METHODS: We evaluated 22 type 2 diabetic patients with normo- or microalbuminuria who took part in the previous study, to clarify which renal histological factors were associated with changes in UAE and the glomerular filtration rate (GFR) during 11.0 ±â€¯3.0 years of follow-up. Light and electron microscopy-based morphometric analyses were performed to quantitatively evaluate the glomerular and interstitial structural changes. RESULTS: In all 22 patients, the GFR was significantly decreased from baseline to follow-up, while the UAE did not change markedly between the 2 periods. After 11 ±â€¯3 years of follow-up, the GFR was significantly lower in the rapid decliner group (annual rate of GFR decline ≥3.0%) than in the non-rapid decliner group (p = 0.017). The index of arteriolar hyalinosis (IAH) at baseline in the rapid decliners was significantly larger than in the non-rapid decliners (p = 0.015). The IAH showed a significant negative correlation with the GFR at follow-up (r = 0.50, p = 0.018) and the annual rate in the GFR decline (r = 0.47, p = 0.027) and significant positive correlations with UAE at follow-up (r = 0.46, p = 0.034) and the annual rate in the UAE increase (r = 0.57, p = 0.005). The GFR at follow-up in patients with IAH ≥2.0 was significantly decreased from baseline (p = 0.042) and significantly lower than that of the patients with IAH <2.0 (p = 0.026), which did not decrease significantly from baseline. The frequency of rapid decliners was larger in the IAH ≥2.0 than in the IAH <2.0 patients (p = 0.037). CONCLUSIONS: Aggravated arteriolar hyalinosis was a risk factor for a rapid GFR decline. This finding might reflect initial changes in early diabetic nephropathy.

Development of glomerular hyperfiltration, a multiphasic phenomenon.

The trajectory of glomerular filtration rate (GFR) in relation to glomerular hyperfiltration (GHF) has been unknown. It was evaluated retrospectively in 23,982 GHF-free health examinees who were followed for 2-10 yr (mean: 5.1 yr). GFR was estimated by the serum creatinine concentration, and GHF was defined as age- and sex-specific estimated GFR (eGFR) ≥ 95% of the Japanese general population. The temporal profile of eGFR was plotted in a GHF-centered way, which was fitted to a random coefficient linear mixed model. Of the 23,982 subjects, 797 and 23,185 subjects developed or did not develop GHF, respectively, so that they were termed as the GHF(+) and GHF(-) groups. At baseline, median eGFR was significantly elevated in the GHF(+) group compared with in the GHF(-) group: 94.1 versus 77.3 mL/min/1.73 m2 (P < 0.001). Elevation of basal eGFR lasted for a mean (SD) of 3.3 (1.9) yr in the GHF(+) group; mean eGFR then rose to the GHF range, which was 108.5 mL/min/1.73 m2. The eGFR decline after the peak was steeper in the GHF(+) group than in the GHF(-) group: -0.984 versus -0.497 mL/min/1.73 m2/yr (P < 0.001). Baseline eGFR, but no other variable, well predicted incident GHF, with an area under the receiver operating characteristic curve of 0.87 (95% confidence interval: 0.86-0.88). In conclusion, GHF occurs as a chronic, multiphasic phenomenon: initially with a sustained GFR elevation for years, followed by a GFR surge to the GHF range, which was accompanied by accelerated GFR declining.

Association between Low Protein Intake and Mortality in Patients with Type 2 Diabetes.

The aim of this study was to investigate the association between protein intake and mortality risk in patients with type 2 diabetes. We analyzed a pooled data of 2494 diabetic patients from two prospective longitudinal studies. Nutritional intake was assessed using a Food Frequency Questionnaire at baseline. Protein intake per body weight (kg) per day was categorized into quartile groups. Adjusted hazard ratios (HRs) and 95% confidence interval (CI) were calculated using Cox regression analysis. During the six-year follow-up, there were 152 incidents of all-cause mortality. The HR for mortality in the lowest quartile of protein intake per body weight compared with the highest quartile was 2.26 (95% CI: 1.34-3.82, p = 0.002) after adjustment for covariates. Subgroup analyses revealed significant associations between low protein intake and mortality in patients aged over 75 years or under 65 years. After further adjustment of the total energy intake, a significant association between protein intake and mortality remained in patients aged ≥ 75 years, whereas the association was attenuated in those aged < 65 years. Our results suggest that adequate protein intake is necessary in older diabetic patients over 75 years, whereas with diabetes, whereas whole optimal total energy intake is required in younger patients with type 2 diabetes.

Vitamin B6 intake and incidence of diabetic retinopathy in Japanese patients with type 2 diabetes: analysis of data from the Japan Diabetes Complications Study (JDCS).

PURPOSE: Although vitamin B6 has been suspected to prevent the progression of diabetic retinopathy, evidence of this in patients with type 2 diabetes based on longitudinal studies is sparse. This study investigated the relationship between vitamin B6 intake and the incidence of diabetic retinopathy in Japanese patients with type 2 diabetes. METHODS: The study was part of an examination of a nationwide cohort of patients with type 2 diabetes aged 40-70 years with HbA1c ≥ 48 mmol/mol. After excluding nonresponders to a dietary survey using the Food Frequency Questionnaire based on food groups, 978 patients were analyzed. Primary outcome was the 8-year risk of a diabetic retinopathy event, and Cox regression analyses estimated hazard ratios (HRs) for retinopathy according to vitamin B6 intake adjusted for age, gender, body mass index, HbA1c, smoking, energy intake, and other confounders. RESULTS: Mean vitamin B6 intake in quartiles ranged from 1.1 to 1.6 mg/day, and half of the participants had vitamin B6 intake below the recommended daily dietary allowance according to dietary reference intakes in Japanese adults (men 1.4 mg/day; women 1.2 mg/day). After adjusting for confounders, HRs for diabetic retinopathy in the 2nd, 3rd, and 4th quartile groups of vitamin B6 intake compared with the 1st quartile group were 1.17 (95% confidence interval 0.81-1.69, p = 0.403), 0.88 (0.58-1.34, p = 0.550), and 0.50 (0.30-0.85, p = 0.010), respectively. CONCLUSIONS: Findings suggested that high vitamin B6 intake was associated with a lower incidence of diabetic retinopathy in Japanese with type 2 diabetes.

Serial renal biopsies in normo- and microalbuminuric patients with type 2 diabetes demonstrate that loss of renal function is associated with a reduction in glomerular filtration surface secondary to mesangial expansion.

AIMS: The aim of the present study was to explore the relationship between changes in renal structure in patients with type 2 diabetes at an early stage of diabetic nephropathy using serial renal biopsies, and change in renal function. METHODS: The study population comprised 10 patients with type 2 diabetes with normo- or microalbuminuria at baseline. Light and electron microscopy-based morphometric analyses were performed to quantitatively evaluate glomerular and interstitial structural changes. Urinary albumin excretion (UAE) and glomerular filtration rate (GFR) were measured annually. A second renal biopsy was performed after a mean of 6.1 ±â€¯2.4 years of follow-up. RESULTS: UAE, GFR, blood pressure and severity of diabetic retinopathy (DR) did not change between the baseline and follow-up. The annual decrease in the surface density of the peripheral glomerular basement membrane (GBM) (Sv[PGBM/glom]) was correlated with the rate of loss of GFR during the six-year follow-up period. The annual change in the Sv(PGBM/glom) was negatively correlated with the change in mesangial volume fraction. CONCLUSIONS: Decreases in the GFR in patients with type 2 diabetes with normo- or microalbuminuria at baseline were associated with a decreased glomerular filtration surface, as a result of mesangial expansion during a mean six years of observation. These findings confirm ongoing pathological progression of glomerulopathy despite no significant change in albuminuria or retinopathy status.

Estimated glomerular filtration rate decline and risk of end-stage renal disease in type 2 diabetes.

BACKGROUND: According to studies by the National Kidney Foundation and Food and Drug Administration, 30% and 40% declines in estimated glomerular filtration rate (eGFR) could be used as surrogate endpoints of end-stage renal disease (ESRD). However, the benefits of using these endpoints in diabetic patients remain unclear. METHODS: This cohort study comprised Japanese patients with type 2 diabetes; those with repeated serum creatinine measurements during a baseline period of 2 years (n = 1868) or 3 years (n = 2001) were enrolled. Subsequent risks of ESRD following eGFR declines were assessed. RESULTS: In the 2-year baseline analysis, the cumulative prevalence of -20%, -30%, -40%, and -53% changes in eGFR were 23.9%, 11.1%, 6.8%, and 3.7%, respectively. There were 133 cases (7.1%) of subsequent ESRD during a median follow-up period of 6.5 years. In the 3-year baseline analysis, the corresponding proportions were 28.1%, 14.0%, 7.7%, and 3.9%, respectively, with 110 participants (5.5%) reaching ESRD during a median follow-up period of 5.5 years. The adjusted hazard ratios of subsequent ESRD following -53%, -40%, -30%, and -20% changes in eGFR during the 2-year baseline period were 22.9 (11.1-47.3), 12.8 (6.9-23.7), 8.2 (4.3-15.5), and 3.9 (2.2-7.0), respectively when compared with the no changes in eGFR. In the 3-year baseline analysis, the corresponding risks were 29.7 (10.8-81.9), 18.4 (7.6-44.7), 12.8 (5.2-32.2), and 5.4 (2.3-12.8), respectively. In the subgroup analysis, similar trends were observed in patients with macroalbuminuria at baseline. CONCLUSIONS: Declines in eGFR were strongly associated with subsequent risk of ESRD in Japanese type 2 diabetic patients. In addition to 30% and 40% declines, a 20% decline in eGFR over 2 years could be considered as a candidate surrogate endpoint of ESRD in diabetic kidney disease.

Urinary IgG4 and Smad1 Are Specific Biomarkers for Renal Structural and Functional Changes in Early Stages of Diabetic Nephropathy.

Diabetic nephropathy (DN) is the major cause of end-stage kidney disease, but early biomarkers of DN risk are limited. Herein we examine urinary IgG4 and Smad1 as additional early DN biomarkers. We recruited 815 patients with type 2 diabetes; 554 patients fulfilled the criteria of an estimated glomerular filtration rate (eGFR) >60 mL/min and no macroalbuminuria at baseline, with follow-up for 5 years. Patients without macroalbuminuria were also recruited for renal biopsies. Urinary IgG4 and Smad1 were determined by enzyme-linked immunoassays using specific antibodies. The specificity, sensitivity, and reproducibility were confirmed for each assay. Increased urinary IgG4 was significantly associated with lower eGFR. The level of urinary IgG4 also significantly correlated with surface density of peripheral glomerular basement membrane (Sv PGBM/Glom), whereas Smad1 was associated with the degree of mesangial expansion-both classic pathological findings in DN. Baseline eGFR did not differ between any groups; however, increases in both urinary IgG4 and Smad1 levels at baseline significantly predicted later development of eGFR decline in patients without macroalbuminuria. These data suggest that urinary IgG4 and Smad1 at relatively early stages of DN reflect underlying DN lesions and are relevant to later clinical outcomes.

Arteriolar Hyalinosis Predicts Increase in Albuminuria and GFR Decline in Normo- and Microalbuminuric Japanese Patients With Type 2 Diabetes.

OBJECTIVE: This study investigated the association between renal histology, as assessed by morphometric analysis using light (LM) and electron (EM) microscopy, and changes in urinary albumin excretion (UAE) and glomerular filtration rate (GFR) in Japanese people with type 2 diabetes in the early stages of diabetic nephropathy. RESEARCH DESIGN AND METHODS: We performed percutaneous renal biopsies in 29 patients with type 2 diabetes (22 men, mean ± SD age 49 ± 10 years and GFR 119 ± 27 mL/min/1.73 m2, with 15 normoalbuminuric [UAE <20 µg/min] and 14 microalbuminuric [UAE 20-200 µg/min]) to clarify which histological factors were associated with changes in UAE and GFR during 8.0 ± 3.5 years' follow-up. Glomerular structural changes including mesangial volume fraction [Vv(Mes/glom)] were estimated using EM, whereas the index of arteriolar hyalinosis (IAH) score was assessed by LM. Patients underwent annual measurement of GFR using iohexol injection with simultaneous urine collections for UAE. RESULTS: Vv(Mes/glom) was negatively correlated with baseline and follow-up GFR but not with UAE. The IAH score was positively correlated with UAE and negatively correlated with GFR at follow-up, but it was not correlated with either UAE or GFR at baseline. GFR at follow-up was significantly decreased from baseline in patients with IAH scores ≥2.0 and significantly lower than in patients with IAH scores <2.0. Patients with IAH scores <2.0 showed no significant change in GFR during follow-up. CONCLUSIONS: Arteriolar hyalinosis is an additional histological predictor for albuminuria increase and GFR decline in normo- and microalbuminuric Japanese people with type 2 diabetes.

Mesangial Cell Mammalian Target of Rapamycin Complex 1 Activation Results in Mesangial Expansion.

Human glomerular diseases can be caused by several different diseases, many of which include mesangial expansion and/or proliferation followed by glomerulosclerosis. However, molecular mechanisms underlying the pathologic mesangial changes remain poorly understood. Here, we investigated the role of the mammalian target of rapamycin complex 1 (mTORC1)-S6 kinase pathway in mesangial expansion and/or proliferation by ablating an upstream negative regulator, tuberous sclerosis complex 1 (TSC1), using tamoxifen-induced Foxd1-Cre mice [Foxd1ER(+) TSC1 mice]. Foxd1ER(+) TSC1 mice showed mesangial expansion with increased production of collagen IV, collagen I, and α-smooth muscle actin in glomeruli, but did not exhibit significant mesangial proliferation or albuminuria. Furthermore, rapamycin treatment of Foxd1ER(+) TSC1 mice suppressed mesangial expansion. Among biopsy specimens from patients with glomerular diseases, analysis of phosphorylated ribosomal protein S6 revealed mesangial cell mTORC1 activation in IgA nephropathy and in lupus mesangial proliferative nephritis but not in the early phase of diabetic nephropathy. In summary, mesangial cell mTORC1 activation can cause mesangial expansion and has clinical relevance for human glomerular diseases. This report also confirms that the tamoxifen-induced mesangium-specific Cre-loxP system is useful for studies designed to clarify the role of the mesangium in glomerular diseases in adults.

Primacy of lowered baseline glomerular filtration rate as a risk for incident chronic kidney disease: A longitudinal study in Japanese subjects.

AIM: Risk profile for incident chronic kidney disease (CKD) in Japanese subjects has not been established. Our aim was to identify risk factors for CKD in Japanese. METHODS: Consecutive 171 536 health examinees (median age 49 years and estimated glomerular filtration rate (eGFR) 78.2 mL/min per 1.73 m2 ) without CKD were re-examined after a median period of 6.2 years. Results of Cox proportional hazards models in randomly assigned two thirds (Derivation cohort) were verified in the rest (Validation cohort). CKD was defined as eGFR <60 mL/min per 1.73 m2 or positive dipstick proteinuria. RESULTS: In the Derivation cohort, CKD developed in 1002 (5.8%) subjects. Seven variables such as lower eGFR, male gender, higher uric acid concentration, lower red cell count and higher age and systolic blood pressure were identified as significant risks for CKD, with lowered eGFR being an overwhelmingly strong risk: adjusted hazard ratio for those with the baseline eGFR <70 mL/min per 1.73 m2 was as high as 90.1. Performance of prediction of CKD by the probability on the basis of the seven risk factors combined was only marginally preferable to eGFR alone. The area under the receiver operating characteristic curve (95% CI) for the prediction was 0.846 (0.826-0.864) and 0.822 (0.802-0.840) (P < 0.01), the kappa statistic was 0.263 and 0.250 (n.s.), and the mean absolute difference between "predicted probability" and "observed" CKD was 1.4% and 1.9% (P = 0.14) by the combined model and eGFR alone, respectively. CONCLUSION: Seven risk factors for incident CKD were identified in Japanese health examinees. However, lowered baseline eGFR outweighed other risks to the degree that eGFR alone was suffice for CKD prediction.

Patients with type 2 diabetes having higher glomerular filtration rate showed rapid renal function decline followed by impaired glomerular filtration rate: Japan Diabetes Complications Study.

AIMS: The Japan Diabetes Complications Study (JDCS), a nation-wide, multicenter, prospective study of patients with type 2 diabetes, reported that hemoglobin A1c (HbA1c), systolic blood pressure, and smoking were risk factors for the onset of macroalbuminuria. This study explored the risk factors for glomerular filtration rate (GFR) decline in the JDCS patients. METHODS: We examined the 1407 JDCS patients (667 women, mean age 59years, 974 normoalbuminuria, 433 microalbuminuria) whose urinary albumin-to-creatinine ratio (UACR) and estimated GFR (eGFR) were determined at baseline with an 8-year follow-up. We divided all the patients into four groups according to baseline eGFR: G1 (120≤eGFR), G2 (90≤eGFR<120), G3 (60≤eGFR<90), G4 (eGFR<60). RESULTS: The eGFRs in groups G1 and G2 decreased at follow-up compared to those at the baseline. The risk of annual eGFR decline rate≥3ml/min/1.73m2 (rapid decliners) increased as the baseline eGFR increased. Advanced age, high HbA1c, and UACR, or diabetic retinopathy at baseline were risk factors for the rapid decliners. Especially the G1 group had a significant risk for the rapid decliners. The frequency of the patients with GFR<60ml/min/1.73m2 at the follow-up amounted to 31.1% in the rapid decliners, which was higher than 12% in the non-rapid decliners. CONCLUSIONS: In normo- and microalbuminuric patients with type 2 diabetes, extra careful attention should be paid to patients with eGFR ≥120ml/min/1.73m2 to detect cases with rapidly decreased GFR under the normal range.