Association of plasma angiogenin with risk of major cardiovascular events in type 2 diabetes

BACKGROUND

Angiogenin, an enzyme belonging to the ribonucleases A superfamily, plays an important role in vascular biology. Here, we sought to study the association of plasma angiogenin and major adverse cardiovascular events (MACEs) in patients with type 2 diabetes (T2D).

METHODS

This prospective study included 1083 T2D individuals recruited from a secondary hospital and a primary care facility. The primary outcome was a composite of four-point MACE (nonfatal myocardial infarction, stroke, unstable angina pectoris leading to hospitalization and cardiovascular death). Circulating angiogenin was measured by a proximity extension assay. Cox regression models were used to evaluate the association of baseline plasma angiogenin with the risk of MACE.

RESULTS

During a median follow-up of 9.3 years, 109 (10%) MACE were identified. Plasma angiogenin was significantly higher in participants with MACE than in those without MACE (P < 0.001). Doubling of plasma angiogenin concentration was associated with a 3.10-fold (95% CI 1.84-5.22) increased risk for MACE. The association was only moderately attenuated after adjustment for demographic and cardiometabolic risk factors (adjusted HR 2.38, 95% CI 1.34-4.23) and remained statistically significant after additional adjustment for estimated glomerular filtration rate (eGFR) and urinary albumin to creatinine ratio (uACR) (adjusted HR 1.90, 95% CI 1.02-3.53). A consistent outcome was obtained when plasma angiogenin was analysed as a categorical variable in tertiles.

CONCLUSIONS

Plasma angiogenin was associated with the risk of future cardiovascular events in patients with T2D and may be a promising novel biomarker for identifying high-risk T2D patients for early management.

Plasma Tryptophan-Kynurenine Pathway Metabolites and Risk for Progression to End-Stage Kidney Disease in Patients With Type 2 Diabetes

OBJECTIVE

We sought to study the associations between plasma metabolites in the tryptophan-kynurenine pathway and the risk of progression to end-stage kidney disease (ESKD) in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Plasma tryptophan, kynurenine, 3-hydroxykynurenine, kynurenic acid, and xanthurenic acid concentrations were measured in discovery (n = 1,915) and replication (n = 346) cohorts. External validation was performed in Chronic Renal Insufficiency Cohort (CRIC) participants with diabetes (n = 1,312). The primary outcome was a composite of incident ESKD (progression to estimated glomerular filtration rate [eGFR] <15 mL/min/1.73 m2, sustained dialysis, or renal death). The secondary outcome was annual eGFR decline.

RESULTS

In the discovery cohort, tryptophan was inversely associated with risk for ESKD, and kynurenine-to-tryptophan ratio (KTR) was positively associated with risk for ESKD after adjustment for clinical risk factors, including baseline eGFR and albuminuria (adjusted hazard ratios [HRs] 0.62 [95% CI 0.51, 0.75] and 1.48 [1.20, 1.84] per 1 SD). High levels of kynurenic acid and xanthurenic acid were associated with low risks of ESKD (0.74 [0.60, 0.91] and 0.74 [0.60, 0.91]). Consistently, high levels of tryptophan, kynurenic acid, and xanthurenic acid were independently associated with a slower eGFR decline, while a high KTR was predictive of a faster eGFR decline. Similar outcomes were obtained in the replication cohort. Furthermore, the inverse association between kynurenic acid and risk of ESKD was externally validated in CRIC participants with diabetes (adjusted HR 0.78 [0.65, 0.93]).

CONCLUSIONS

Accelerated catabolism of tryptophan in the kynurenine pathway may be involved in progressive loss of kidney function. However, shunting the kynurenine pathway toward the kynurenic acid branch may potentially slow renal progression.

Urine Leucine-Rich α-2 Glycoprotein 1 (LRG1) Predicts the Risk of Progression to End-Stage Kidney Disease in Patients With Type 2 Diabetes

OBJECTIVE

Leucine-rich α-2 glycoprotein 1 (LRG1) was recently identified as an amplifier of transforming growth factor-β (TGF-β)-induced kidney fibrosis in animal models. We aimed to study whether urine LRG1 is associated with risk of progression to end-stage kidney disease (ESKD) in individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 1,837 participants with type 2 diabetes and estimated glomerular filtration rate (eGFR) >30 mL/min/1.73 m2 were recruited from a regional hospital and a primary care facility. Association of urine LRG1 with risk of ESKD (progression to sustained eGFR <15 mL/min/1.73 m2, dialysis, or death resulting from renal causes) was assessed by survival analyses.

RESULTS

During a median follow-up of 8.6 (interquartile range 5.8-9.6) years, 134 incident ESKD events were identified. Compared with those in the lowest tertile, participants with baseline urine LRG1 in the highest tertile had a 1.91-fold (95% CI 1.04-3.50) increased risk of progression to ESKD, after adjustment for cardiorenal risk factors, including eGFR and albuminuria. As a continuous variable, 1 SD increment in urine LRG1 was associated with a 1.53-fold (95% CI 1.19-1.98) adjusted risk of ESKD. Of note, the association of urine LRG1 with ESKD was independent of plasma LRG1. Moreover, urine LRG1 was associated with rapid kidney function decline and progression to macroalbuminuria, two common pathways leading to ESKD.

CONCLUSIONS

Urine LRG1, a TGF-β signaling modulator, predicts risk of progression to ESKD independently of clinical risk factors in patients with type 2 diabetes, suggesting that it may be a novel factor involved in the pathophysiological pathway leading to kidney disease progression.

Clinical variable-based cluster analysis identifies novel subgroups with a distinct genetic signature, lipidomic pattern and cardio-renal risks in Asian patients with recent-onset type 2 diabetes

AIMS/HYPOTHESIS

We sought to subtype South East Asian patients with type 2 diabetes by de novo cluster analysis on clinical variables, and to determine whether the novel subgroups carry distinct genetic and lipidomic features as well as differential cardio-renal risks.

METHODS

Analysis by k-means algorithm was performed in 687 participants with recent-onset diabetes in Singapore. Genetic risk for beta cell dysfunction was assessed by polygenic risk score. We used a discovery-validation approach for the lipidomics study. Risks for cardio-renal complications were studied by survival analysis.

RESULTS

Cluster analysis identified three novel diabetic subgroups, i.e. mild obesity-related diabetes (MOD, 45%), mild age-related diabetes with insulin insufficiency (MARD-II, 36%) and severe insulin-resistant diabetes with relative insulin insufficiency (SIRD-RII, 19%). Compared with the MOD subgroup, MARD-II had a higher polygenic risk score for beta cell dysfunction. The SIRD-RII subgroup had higher levels of sphingolipids (ceramides and sphingomyelins) and glycerophospholipids (phosphatidylethanolamine and phosphatidylcholine), whereas the MARD-II subgroup had lower levels of sphingolipids and glycerophospholipids but higher levels of lysophosphatidylcholines. Over a median of 7.3 years follow-up, the SIRD-RII subgroup had the highest risks for incident heart failure and progressive kidney disease, while the MARD-II subgroup had moderately elevated risk for kidney disease progression.

CONCLUSIONS/INTERPRETATION

Cluster analysis on clinical variables identified novel subgroups with distinct genetic, lipidomic signatures and varying cardio-renal risks in South East Asian participants with type 2 diabetes. Our study suggests that this easily actionable approach may be adapted in other ethnic populations to stratify the heterogeneous type 2 diabetes population for precision medicine.

Risk of Incident Heart Failure in Individuals With Early-Onset Type 2 Diabetes

CONTEXT

Early-onset diabetes has been associated with unfavorable cardiovascular risk but data on heart failure (HF) in this subpopulation are scarce.

OBJECTIVE

We aimed to study the risk of, and risk factors for, incident HF in individuals with early-onset type 2 diabetes.

METHODS

We studied 606 individuals with type 2 diabetes diagnosed before 40 years of age (early-onset) and 1258 counterparts with diabetes diagnosed from 41 to 65 years of age (usual-onset) with no HF history, at a regional hospital, over a median follow-up period of 7.1 years. Incident HF by European Cardiology Society criteria was determined.

RESULTS

A total of 62 and 108 HF events were identified in the early- and usual-onset groups (1.55 and 1.29 per 100 patient-years), respectively. Compared with usual-onset counterparts, individuals with early-onset diabetes had a 1.20-fold unadjusted (95% CI, 0.88-1.63; P = 0.26) and 1.91-fold age-adjusted (95% CI, 1.37-2.66; P < 0.001) hazard ratio (HR) for incident HF. Adjustment for traditional cardiometabolic risk factors only moderately mitigated the hazards (adjusted HR 1.69; 95% CI, 1.19-2.40; P = 0.003). However, additional adjustment for estimated glomerular filtration rate and albuminuria markedly attenuated the association of early-onset age with incident HF (adjusted HR 1.24; 95% CI, 0.87-1.77; P = 0.24). Notably, a long diabetes duration was not significantly associated with HF risk after accounting for kidney measures.

CONCLUSION

Individuals with early-onset diabetes have at least the same absolute risk and a 2-fold age-adjusted relative risk for incident HF. Excess cardiorenal risk factors but not a long diabetes duration are main drivers for HF development in this diabetic population.

Association of Plasma Leucine-Rich Alpha-2 Glycoprotein 1 (LRG1) with All-Cause and Cause-Specific Mortality in Individuals with Type 2 Diabetes

BACKGROUND

Leucine-rich alpha-2 glycoprotein 1 (LRG1) is a circulating protein in the transforming growth factor-beta superfamily. We sought to study whether LRG1 might predict risk for all-cause and cause-specific mortality in individuals with type 2 diabetes.

METHODS

2012 outpatients with type 2 diabetes were followed for a median of 7.2 years and 188 death events were identified. Association of LRG1 with risk for mortality was assessed by multivariable Cox regression models.

RESULTS

Participants with a higher concentration of LRG1 had an increased risk for all-cause mortality [HR (95% CI), 1.76 (1.03-3.01), 1.75 (1.03-2.98), and 4.37 (2.72-7.02) for quartiles 2, 3, and 4, respectively, compared to quartile 1]. The association remained significant after adjustment for known cardio-renal risk factors including estimated glomerular filtration rate and albuminuria [adjusted HR 2.76 (1.66-4.59), quartile 4 versus 1]. As a continuous variable, a 1-SD increment in LRG1 was associated with 1.34 (1.14-1.57)-fold adjusted risk for all-cause mortality. High plasma LRG1 was independently associated with mortality attributable to cardiovascular disease, infection, and renal diseases. Adding LRG1 into a clinical variable-based model improved discrimination (c statistics from 0.828 to 0.842, P = 0.006) and reclassification (net reclassification improvement 0.47, 95% CI 0.28-0.67) for prediction of 5-year all-cause mortality.

CONCLUSION

Plasma LRG1 predicts risk for all-cause mortality and mortality attributable to cardiovascular disease, infection, and renal disease independent of known cardio-renal risk factors. It may be a potential novel biomarker to improve risk stratification in individuals with type 2 diabetes.

Association of leukocyte telomere length with chronic kidney disease in East Asians with type 2 diabetes: a Mendelian randomization study

Background

Chronic kidney disease (CKD) is common among people with type 2 diabetes (T2D), and increases the risk of kidney failure and cardiovascular diseases. Shorter leukocyte telomere length (LTL) is associated with CKD in patients with T2D. We previously reported single-nucleotide polymorphisms (SNPs) associated with LTL in an Asian population. In this study, we elucidated the association of these SNPs with CKD in patients with T2D using the Mendelian randomization (MR) approach.

Methods

The cross-sectional association of 16 LTL SNPs with CKD, defined as an estimated glomerular filtration rate of <60 mL/min/1.73 m², was assessed among 4768 (1628 cases and 3140 controls) participants in the Singapore Study of Macro-angiopathy and Micro-vascular Reactivity in T2D and Diabetic Nephropathy cohorts. MR analysis was performed using the random-effect inverse-variance weighted (IVW) method, the weighted median, MR-Egger and Radial MR adjusted for age and sex-stratified by cohorts and ethnicity (Chinese and Malays), then meta-analyzed.

Results

Genetically determined shorter LTL was associated with increased risk of CKD in patients with T2D (meta-IVW adjusted odds ratio = 1.51, 95% confidence interval 1.12–2.12, P = 0.007, P_het = 0.547). Similar results were obtained following sensitivity analysis. MR-Egger analysis (intercept) suggested no evidence of horizontal pleiotropy (β = 0.010, P = 0.751).

Conclusions

Our findings suggest that genetically determined LTL is associated with CKD in patients with T2D. Further studies are warranted to elucidate the causal role of telomere length in CKD progression.

Association of leukocyte telomere length with obesity-related traits in Asian children with early-onset obesity

BACKGROUND

Leukocyte telomere length (LTL) is associated with obesity and obesity-related traits, and there are ethnic-specific determinants of LTL.

OBJECTIVE

To evaluate LTL associations with obesity and metabolic parameters in Asian children with early-onset obesity.

METHODS

Genomic DNA was extracted from peripheral blood leukocytes of a cohort of children with (N = 371) and without obesity (N = 23), and LTL was measured using quantitative PCR (qPCR). Blood plasma was used for metabolic phenotyping. Statistical analysis was performed using SPSS and STATA.

RESULTS

Children with obesity had shorter LTL (coefficient = -0.683, P_Adj = 1.24 × 10^-3 ) as compared to children who were lean. LTL was found to be associated with waist circumference (coefficient = -0.326, P_Adj = 0.044) and skin-fold measures (coefficient between 0.267 and 0.301, P_Adj between 4.27 × 10^-4 and 7.06 × 10^-7 ) in children with obesity. However, no significant associations were observed between LTL and metabolic parameters, and between LTL and inflammatory cytokines. LTL also did not significantly mediate the risk of non-alcoholic fatty liver disease (NAFLD) in children with obesity.

CONCLUSIONS

We showed for the first time that Asian children with severe obesity had shorter LTL, and the shortening of LTL was associated with other adiposity measures including waist circumference and skin-fold measurements.

Low frequency variants associated with leukocyte telomere length in the Singapore Chinese population

The role of low frequency variants associated with telomere length homeostasis in chronic diseases and mortalities is relatively understudied in the East-Asian population. Here we evaluated low frequency variants, including 1,915,154 Asian specific variants, for leukocyte telomere length (LTL) associations among 25,533 Singapore Chinese samples. Three East Asian specific variants in/near POT1, TERF1 and STN1 genes are associated with LTL (Meta-analysis P 2.49×10-14-6.94×10-10). Rs79314063, a missense variant (p.Asp410His) at POT1, shows effect 5.3 fold higher and independent of a previous common index SNP. TERF1 (rs79617270) and STN1 (rs139620151) are linked to LTL-associated common index SNPs at these loci. Rs79617270 is associated with cancer mortality [HR95%CI = 1.544 (1.173, 2.032), PAdj = 0.018] and 4.76% of the association between the rs79617270 and colon cancer is mediated through LTL. Overall, genetically determined LTL is particularly associated with lung adenocarcinoma [HR95%CI = 1.123 (1.051, 1.201), Padj = 0.007]. Ethnicity-specific low frequency variants may affect LTL homeostasis and associate with certain cancers.

Associations of young onset age and genetic risk of beta cell dysfunction with glycaemic progression in individuals with type 2 diabetes

AIM

To study the relationship between genetic risk of beta cell dysfunction, young onset age and glycaemic progression in individuals with type 2 diabetes (T2D).

MATERIALS AND METHODS

1385 T2D outpatients were included in cross-sectional sub-study and 730 insulin-naïve outpatients were followed for 3 years in prospective sub-study. Genetic risk score (GRS) was derived from 24 beta cell dysfunction-related single nucleotide polymorphisms, with lower and upper 25 percentiles defined as low and high genetic risk. Glycaemic progression was defined as requirement for sustained insulin therapy.

RESULTS

388 participants in cross-sectional and 128 in prospective sub-study experienced glycaemic progression. Young onset age (T2D diagnosis below 40 year-old) was associated with high risk of glycaemic progression as compared to usual-onset counterparts (adjusted OR 1.64 [95% CI 1.14-2.36], and 2.92 [95% CI 1.76-4.87] in cross-sectional and prospective sub-study, respectively). As compared to those with intermediate risk, a low GRS was associated with lower risk for glycaemic progression (adjusted OR 0.72 [95% CI 0.49-1.06], and 0.51 [95% CI 0.29-0.90]) whereas a high GRS was not significantly associated with glycaemic progression. Notably, the association of young-onset T2D with high risk of glycaemic progression was independent of known clinical risk factors and beta cell dysfunction GRS (P interaction > 0.10).

CONCLUSION

Young onset age and low genetic risk of beta cell dysfunction are independently associated with risk of glycaemic progression. Our data do not support that genetic risk modulates the risk of glycaemic progression in individuals with young-onset T2D.

Association of Plasma Leucine-Rich α-2 Glycoprotein 1, a Modulator of Transforming Growth Factor-β Signaling Pathway, With Incident Heart Failure in Individuals With Type 2 Diabetes

OBJECTIVE

Leucine-rich α-2 glycoprotein 1 (LRG1) is a circulating protein potentially involved in several pathways related to pathogenesis of heart failure (HF). We aimed to study whether plasma LRG1 is associated with risks of incident HF and hospitalization attributable to HF (HHF) in individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 1,978 individuals with type 2 diabetes were followed for a median of 7.1 years (interquartile range 6.1-7.6). Association of LRG1 with HF was studied using cause-specific Cox regression models.

RESULTS

In follow-up, 191 incident HF and 119 HHF events were identified. As compared with quartile 1, participants with LRG1 in quartiles 3 and 4 had 3.60-fold (95% CI 1.63-7.99) and 5.99-fold (95% CI 2.21-16.20) increased risk of incident HF and 5.88-fold (95% CI 1.83-18.85) and 10.44-fold (95% CI 2.37-45.98) increased risk of HHF, respectively, after adjustment for multiple known cardiorenal risk factors. As a continuous variable, 1 SD increment in natural log-transformed LRG1 was associated with 1.78-fold (95% CI 1.33-2.38) adjusted risk of incident HF and 1.92-fold (95% CI 1.27-2.92) adjusted risk of HHF. Adding LRG1 to the clinical variable-based model improved risk discrimination for incident HF (area under the curve [AUC] 0.79-0.81; P = 0.02) and HHF (AUC 0.81-0.84; P = 0.02).

CONCLUSIONS

Plasma LRG1 is associated with risks of incident HF and HHF, suggesting that it may potentially be involved in pathogenesis of HF in individuals with type 2 diabetes. Additional studies are warranted to determine whether LRG1 is a novel biomarker for HF risk stratification.

Correlation of Telomere Length in Adipose Tissue and Leukocytes and its Association with Postsurgical Weight Loss

OBJECTIVE

The aim of this study was to determine the relationship between telomere length (TL) in subcutaneous adipose tissue (SAT), visceral adipose tissues (VAT), and leukocytes, as well as to examine the associations of TL in these tissues with postsurgical weight loss in Asians with severe obesity.

METHODS

Presurgery TL was measured in leukocytes, SAT, and VAT of 91 patients who underwent weight loss surgery. Correlation between TL in multiple tissues was assessed using Pearson correlation. The association of presurgery TL and postsurgical weight loss at 6 or 12 months, expressed as a percentage of weight loss, was determined using linear regression in 70 patients.

RESULTS

Telomeres were longer in VAT compared with those in leukocytes and SAT (P < 0.001) but were highly correlated between tissues. The strongest correlation was observed between TL in VAT and leukocytes (r = 0.739, P = 6.22 × 10^-17 ). Compared with individuals in the highest tertile, those in the lowest tertile of VAT TL showed greater weight loss (β = 6.23, SE = 3.10, P = 0.044) independent of age, sex, ethnicity, types of surgery, diabetes condition, preoperative BMI, and follow-up period.

CONCLUSIONS

Among patients with severe obesity, TL in leukocytes and adipose tissue was highly correlated. However, there was variability in the association of TL in these tissues with weight loss after surgery.

Aortic pulse wave velocity, central pulse pressure, augmentation index and chronic kidney disease progression in individuals with type 2 diabetes: a 3- year prospective study

BACKGROUND

Pulse wave velocity (PWV), central pulse pressure and augmentation index are arterial stiffness- related hemodynamic parameters but their associations with renal outcome are still controversial. We hereby aim to study, 1) which hemodynamic parameter is independently associated with progressive chronic kidney disease (CKD), 2) the association of 3-year change in PWV with CKD progression and, 3) the additive predictive value of PWV for progressive CKD.

METHODS

Carotid- femoral PWV, central pulse pressure and augmentation index were measured in 1444 participants with type 2 diabetes at baseline and 3 years apart. Progressive CKD was defined as confirmed eGFR decline 40% or greater.

RESULTS

In the follow-up, 102 participants experienced progressive CKD. All 3 hemodynamic parameters were significantly associated with progressive CKD In univariable analysis. However, only PWV remained statistically significant after adjustment for known clinical risk factors and the other 2 hemodynamic parameters (OR 1.14 [95% CI 1.01-1.29] per m/s increment). One m/s regression (decrement) in PWV in the 3-year follow-up was associated with 26% lower adjusted- risk of progressive CKD (OR 0.74, 95% CI 0.56-0.97). Adding PWV onto traditional risk factor- based model significantly improved classification (net reclassification improvement 0.25, 95% CI 0.05-0.45, P = 0.01) and positive prediction rate (24.5 to 32.3%).

CONCLUSIONS

Of 3 arterial stiffness- related hemodynamic parameters, only PWV is independently associated with progressive CKD. PWV may be a potential intervention target to mitigate risk of CKD progression and also a biomarker to improve risk-stratification of adverse renal outcome in individuals with type 2 diabetes.

Risk of progressive chronic kidney disease in individuals with early-onset type 2 diabetes: a prospective cohort study

BACKGROUND

The progression trajectory of renal filtration function has not been well characterized in patients with early-onset type 2 diabetes mellitus (T2DM) although albuminuria is often reported in this population. We aim to study the risk of progressive chronic kidney disease (CKD) in individuals with early-onset T2DM.

METHODS

In total, 1189 T2DM participants were followed for 3.9 (interquartile range 3.2-4.7) years. Progressive CKD was defined as estimated glomerular filtration rate (eGFR) decline of ≥5 mL/min/1.73 m2 per year. Early-onset T2DM was defined as age at T2DM diagnosis between 18 and 30 years.

RESULTS

Compared with later-onset counterparts (N = 1032), participants with early-onset T2DM (N = 157) were more obese and had poorer glycaemic control at baseline. In the follow-up, 24.2% and 15.6% experienced progressive CKD in early-onset and later-onset participants, respectively (P = 0.007). Logistic regression suggested that participants with early-onset T2DM had 2.63-fold [95% confidence interval (CI) 1.46-4.75] higher risk of progressive CKD after accounting for multiple traditional risk factors. Furthermore, the excess risk of progressive CKD associated with early-onset T2DM mainly occurred in participants with preserved renal function [eGFR ≥60 mL/min/1.73 m2, odds ratio (OR) 2.85, 95% CI 1.50-5.42] and was more pronounced in those with diabetes duration <10 years (OR 3.67, 95% CI 1.51-8.90).

CONCLUSIONS

Individuals with early-onset T2DM have a higher risk of progressive CKD. The excess risk mainly exhibits in early stage of CKD and cannot be solely attributed to traditional risk factors and a longer diabetes duration.

Association of Urine Haptoglobin With Risk of All-Cause and Cause-Specific Mortality in Individuals With Type 2 Diabetes: A Transethnic Collaborative Work

OBJECTIVE

Haptoglobin is an acute-phase reactant with pleiotropic functions. We aimed to study whether urine haptoglobin may predict risk of mortality in people with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We employed a transethnic approach with a cohort of Asian origin (Singapore) (N = 2,061) and a cohort of European origin (France) (N = 1,438) included in the study. We used survival analyses to study the association of urine haptoglobin with risk of all-cause and cause-specific mortality.

RESULTS

A total of 365 and 525 deaths were registered in the Singapore cohort (median follow-up 7.5 years [interquartile range 3.5-12.8]) and French SURDIAGENE cohort (median follow-up 6.8 years [interquartile range 4.3-10.5], respectively. Singapore participants with urine haptoglobin in quartiles 2 to 4 had higher risk for all-cause mortality compared with quartile 1 (unadjusted hazard ratio [HR] 1.47 [95% CI 1.02-2.11], 2.28 [1.62-3.21], and 4.64 [3.39-6.35], respectively). The association remained significant in quartile 4 after multiple adjustments (1.68 [1.15-2.45]). Similarly, participants in the French cohort with haptoglobin in quartile 4 had significantly higher hazards for all-cause mortality compared with quartile 1 (unadjusted HR 2.67 [2.09-3.42] and adjusted HR 1.49 [1.14-1.96]). In both cohorts, participants in quartile 4 had a higher risk of mortality attributable to cardiovascular disease and infection but not malignant tumor.

CONCLUSIONS

Urine haptoglobin predicts risk of mortality independent of traditional risk factors, suggesting that it may potentially be a novel biomarker for risk of mortality in patients with type 2 diabetes.

Arterial Stiffness Modulates the Association of Resting Heart Rate With Rapid Renal Function Decline in Individuals With Type 2 Diabetes Mellitus

Objective:

Resting heart rate (RHR) has been associated with cardiovascular risk, but data on renal outcomes are still scarce. We aimed to study the association of RHR with rapid renal function decline (RRFD) and to explore whether the association of RHR with RRFD is modulated by arterial stiffness in individuals with type 2 diabetes mellitus.

Approach and Results:

One thousand one hundred forty-two Asian people with type 2 diabetes mellitus were followed for 3.9±0.9 years in a regional hospital and a primary care facility. RRFD was defined as eGFR decline of 5 mL/min per 1.73 m2 or greater per year. Arterial stiffness was assessed by carotid-femoral pulse wave velocity. One hundred sixty-eight participants (15%) were classified as having RRFD. Participants with elevated RHR were younger, had higher levels of HbA1c, albuminuria, C-reactive protein, and pulse wave velocity. Compared with the lowest quartile, participants in quartile 4 had a higher risk for RRFD after adjustment for known risk factors (adjusted odds ratio 1.91 [1.11–3.28]). RHR improved discrimination and net reclassification for prediction of RRFD above traditional risk factors. Remarkably, arterial stiffness modulated the association of RHR with RRFD ( P for interaction =0.03). RHR was significantly associated with risk of RRFD only in those with increased arterial stiffness (pulse wave velocity above age-reference value 7.7 m/s).

Conclusions:

RHR independently predicts RRFD, and the association is modulated by arterial stiffness. An elevated heart rate may be one factor in the spectrum of cardiovascular risk factors associated with renal functional impairment, especially in those with type 2 diabetes mellitus and an increased arterial stiffness.

Clinical Determinants of Diabetes Progression in Multiethnic Asians with Type 2 Diabetes - A 3-Year Prospective Cohort Study

INTRODUCTION

The risk for diabetes progression varies greatly in individuals with type 2 diabetes mellitus (T2DM). We aimed to study the clinical determinants of diabetes progression in multiethnic Asians with T2DM.

MATERIALS AND METHODS

A total of 2057 outpatients with T2DM from a secondary-level Singapore hospital were recruited for the study. Diabetes progression was defined as transition from non-insulin use to requiring sustained insulin treatment or glycated haemoglobin (HbA1c) ≥8.5% when treated with 2 or more oral hypoglycaemic medications. Multivariable logistic regression (LR) was used to study the clinical and biochemical variables that were independently associated with diabetes progression. Forward LR was then used to select variables for a parsimonious model.

RESULTS

A total of 940 participants with no insulin use or indication for insulin treatment were analysed. In 3.2 ± 0.4 (mean ± SD) years' follow-up, 163 (17%) participants experienced diabetes progression. Multivariable LR revealed that age at T2DM diagnosis (odds ratio [95% confidence interval], 0.96 [0.94-0.98]), Malay ethnicity (1.94 [1.19-3.19]), baseline HbA1c (2.22 [1.80-2.72]), body mass index (0.96 [0.92-1.00]) and number of oral glucose-lowering medications (1.87 [1.39-2.51]) were independently associated with diabetes progression. Area under receiver operating characteristic curve of the parsimonious model selected by forward LR (age at T2DM diagnosis, Malay ethnicity, HbA1c and number of glucose-lowering medication) was 0.76 (95% CI, 0.72-0.80).

CONCLUSION

Young age at T2DM diagnosis, high baseline HbA1c and Malay ethnicity are independent determinants of diabetes progression in Asians with T2DM. Further mechanistic studies are needed to elucidate the pathophysiology underpinning progressive loss of glycaemic control in patients with T2DM.

Association of haptoglobin phenotype with incident acute myocardial infarction in Chinese patients with type 2 diabetes

Background

Haptoglobin (Hp) is an abundant plasma protein with anti-oxidant properties. Hp polymorphism is associated with cardio-metabolic dysfunction but the allele conferring risk of developing acute myocardial infarction (AMI) in type 2 diabetes (T2D) patients is unclear. This study aimed to investigate the association of Hp phenotype (Hp 1-1, 2-1 and 2-2) with incident AMI in Chinese T2D patients.

Methods

This prospective study included Chinese T2D participants from the Singapore Study of Macro-angiopathy and Micro-vascular Reactivity in Type 2 Diabetes (SMART2D) and Diabetic Nephropathy (DN) cohorts. Information on incidence of non-fatal AMI was collected by data linkage with the Singapore Myocardial Infarction Registry. Hp phenotype was determined using enzyme-linked immunosorbent assay. Cox proportional hazards regression models were used to evaluate the association of Hp phenotype with incident AMI, adjusted for traditional risk factors separately in two cohorts, then meta-analysed.

Results

In total, 2324 Chinese participants (SMART2D; N = 1034, mean age [SD] of 59 [11]) and (DN: N = 1290, mean age [SD] of 58 [12]) were included in this study. There were total of 30 (56 events per 10,000 patient-years) and 99 (128 events per 10,000 patient-years) AMI events in SMART2D and DN cohorts respectively. In meta-analysis, presence of Hp 1 allele conferred 43% (hazard ratio [HR] = 1.43 [95% CI 1.10–1.87], P = 0.008, P_het = 0.413) increased risk of incident AMI, independent of age, sex, smoking, body mass index, HbA1c, diabetes duration, lipids, hypertension, renal function and usage of insulin and RAS antagonist. In adjusted model, compared to Hp 2-2 groups, individuals with Hp 1-1 (HR = 2.18 [95% CI 1.19–3.76], P = 0.010, P_het = 0.193) and Hp 2-1 (HR = 1.45 [95% CI 0.98–2.14], P = 0.065, P_het = 0.576) were at a higher risk of incident AMI. Moreover, compared to Hp 2-2 groups, non-Hp 2-2 groups (Hp 1-1 and Hp 2-1) were at 55% increased risk of incident AMI (HR = 1.55 [95% CI 1.07–2.24], P = 0.021, P_het = 0.940).

Conclusions

Hp 1-1 phenotype was associated with increased risk of incident AMI, independent of traditional risk factors, in Chinese patients with T2D. Hp phenotyping may allow for identification of T2D individuals at higher risk for onset of AMI. However, further studies are needed to understand the underlying mechanism between Hp alleles and risk for AMI.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0867-4) contains supplementary material, which is available to authorized users.

Cause-Specific Mortality in Multiethnic South East Asians With Type 2 Diabetes Mellitus

Data on specific causes of mortality in South East Asians with type 2 diabetes mellitus (T2DM) remain scarce. We followed 2061 outpatients with T2DM (Chinese 63%, Malays 20%, and Asian Indians 17%) for an average of 5.5 (standard deviation = 2.9) years and identified 365 death events by data linkage with national death registry. Cardiovascular disease was the main cause of mortality (44%), followed by renal disease (17%), infection (17%), cancer (14%), and others causes (8%). Survival analyses revealed that risks for all-cause and cause-specific mortality vary greatly among ethnic groups. Presence of diabetic kidney disease was an independent risk factor for death attributable to cardiovascular disease, renal disease, and infection, while HbA1c level predicted all major causes of deaths even after accounting for multiple other risk factors. These data reinforce the importance of glycemic control and prevention of diabetic kidney disease for mitigation of mortality burden in multiethnic Asians with T2DM.

Relationship Between Fasting Plasma Glucagon Level and Renal Function-A Cross-Sectional Study in Individuals With Type 2 Diabetes

Background and Aim

The kidney is the main site for glucagon clearance. However, a recent study showed that hyperglucagonemia in patients with end-stage renal disease might not be caused by full-length intact glucagon. Additionally, the relationship between glucagon and renal function in early-stage chronic kidney disease (CKD) has not yet been characterized. We studied the association of fasting glucagon with renal function across a wide range of glomerular filtration rates (GFRs) in participants with type 2 diabetes.

Participants and Methods

326 participants with type 2 diabetes and renal function spanning CKD stage 1 to 5 were included in the present cross-sectional study. Fasting full-length plasma glucagon was quantified using a newly developed ELISA (Mercodia AB, Uppsala, Sweden).

Results

The fasting plasma glucagon level was elevated linearly from CKD stage 1 to 5 [from a median of 2.5 pM (interquartile range, 1.4 to 4.7) in CKD 1 to a median of 8.3 pM (interquartile range, 5.9 to 12.8) in CKD 5; P for trend < 0.0001], from as early as CKD stage 2 compared with that in stage 1 (Bonferroni-corrected P < 0.0001). The estimated GFR and homeostatic model of assessment–insulin resistance were the main determinants of the fasting glucagon level. These explained 14.3% and 10.3% of the glucagon variance, respectively. Albuminuria was not associated with fasting glucagon after adjustment for estimated GFR.

Conclusions

Fasting full-length glucagon was elevated linearly with the deterioration in renal function in individuals with type 2 diabetes, even in those with early CKD. In addition to renal function, insulin sensitivity was also a main determinant of glucagon variance.

Urine Tricarboxylic Acid Cycle Metabolites Predict Progressive Chronic Kidney Disease in Type 2 Diabetes

CONTEXT

Metabolites in the tricarboxylic acid (TCA) cycle are not only involved in energy metabolism but also play important roles in non-energy production activities.

OBJECTIVE

To study whether baseline urine key TCA cycle metabolites (lactate, pyruvate, citrate, α-ketoglutaric acid, succinate, fumarate, and malate) independently predict risk of chronic kidney disease (CKD) progression [fast estimated glomerular filtration rate (eGFR) decline] in individuals with type 2 diabetes mellitus (T2DM).

DESIGN

One discovery and one validation nested case-control studies in two independent T2DM cohorts.

SETTING AND PARTICIPANTS

Subjects with T2DM were recruited and followed in a regional hospital and at a primary care facility.

MAIN OUTCOME MEASURES

eGFR trajectory (slope) was estimated by linear regression. Progressive CKD was defined as eGFR decline of ≥5 mL/min/1.73 m2 per year.

RESULTS

As compared with those with stable renal function (n = 271), participants who experienced progressive CKD (n = 116) had a lower level of urine citrate but significantly higher levels of lactate, fumarate, and malate levels at baseline. Both fumarate and malate predicted progressive CKD independent of traditional cardio-renal risk factors, including eGFR and albuminuria. Fumarate interacted with sex (P for interaction = 0.03) and independently predicted progressive CKD in male but not female participants. All these findings were reproducible in a validation study (case n = 96, control n = 402). Exploratory analysis suggested that fumarate might partially mediate the effect of oxidative stress on CKD progression.

CONCLUSIONS

Key TCA cycle metabolites, especially fumarate, may be involved in the pathophysiologic pathway independent of traditional cardio-renal risk factors, leading to CKD progression in patients with T2DM.

Tpz1TPP1 SUMOylation reveals evolutionary conservation of SUMO-dependent Stn1 telomere association

Elongation of the telomeric overhang by telomerase is counteracted by synthesis of the complementary strand by the CST complex, CTC1(Cdc13)/Stn1/Ten1. Interaction of budding yeast Stn1 with overhang-binding Cdc13 is increased by Cdc13 SUMOylation. Human and fission yeast CST instead interact with overhang-binding TPP1/POT1. We show that the fission yeast TPP1 ortholog, Tpz1, is SUMOylated. Tpz1 SUMOylation restricts telomere elongation and promotes Stn1/Ten1 telomere association, and a SUMO-Tpz1 fusion protein has increased affinity for Stn1. Our data suggest that SUMO inhibits telomerase through stimulation of Stn1/Ten1 action by Tpz1, highlighting the evolutionary conservation of the regulation of CST function by SUMOylation.

Inhibition of poly (ADP-Ribose) polymerase-1 in telomerase deficient mouse embryonic fibroblasts increases arsenite-induced genome instability

Background

The telomerase enzyme is a viable target for anti-cancer therapy given the innate differences in telomerase activity between tumour cells and normal somatic cells. However, the time lag between telomerase inhibition and telomeres becoming critically short to trigger cell death, allows cancer cells to acquire drug resistance. Inhibition of DNA repair pathways along with telomerase could be an alternative strategy to enhance anti-tumour effects and circumvent the possibility of drug resistance. Poly (ADP-Ribose) Polymerase-1 (PARP-1), an important DNA damage sensor and a DNA repair factor, has important roles in maintaining telomeres and chromosomal stability. In this study, the effects of combined inhibition of PARP-1 and telomerase in mouse embryonic fibroblasts (MEFs) following sodium arsenite exposure (a carcinogen and potent DNA damaging agent), were evaluated.

Results

Inhibition of PARP in telomerase deficient MEFs induced an increase in arsenite-induced DNA damage as compared to control cells. Combined inhibition also resulted in enhanced genomic instability, demonstrated by elevated micronuclei induction and chromosomal aberrations with decreased cell survival. In addition, telomerase inhibition in PARP-1 deficient MEFs led to greater telomere shortening and increased genomic instability.

Conclusions

Our study demonstrated that the co-inhibition of PARP-1 and telomerase in MEFs rendered cells more susceptible to DNA damaging agents. Hence, these results offer support for the use of combined inhibition of PARP-1 and telomerase as a strategy to minimise the problems associated with long-term telomerase inhibition in cancer therapeutics.