Markers of insulin resistance are strong risk factors for retinopathy incidence in type 1 diabetes

Role of Systemic Factors in Improving the Prognosis of Diabetic Retinal Disease and Predicting Response to Diabetic Retinopathy Treatment

Topic

To review clinical evidence on systemic factors that might be relevant to update diabetic retinal disease (DRD) staging systems, including prediction of DRD onset, progression, and response to treatment.

Clinical relevance

Systemic factors may improve new staging systems for DRD to better assess risk of disease worsening and predict response to therapy.

Methods

The Systemic Health Working Group of the Mary Tyler Moore Vision Initiative reviewed systemic factors individually and in multivariate models for prediction of DRD onset or progression (i.e., prognosis) or response to treatments (prediction).

Results

There was consistent evidence for associations of longer diabetes duration, higher glycosylated hemoglobin (HbA1c), and male sex with DRD onset and progression. There is strong trial evidence for the effect of reducing HbA1c and reducing DRD progression. There is strong evidence that higher blood pressure (BP) is a risk factor for DRD incidence and for progression. Pregnancy has been consistently reported to be associated with worsening of DRD but recent studies reflecting modern care standards are lacking. In studies examining multivariate prognostic models of DRD onset, HbA1c and diabetes duration were consistently retained as significant predictors of DRD onset. There was evidence of associations of BP and sex with DRD onset. In multivariate prognostic models examining DRD progression, retinal measures were consistently found to be a significant predictor of DRD with little evidence of any useful marginal increment in prognostic information with the inclusion of systemic risk factor data apart from retinal image data in multivariate models. For predicting the impact of treatment, although there are small studies that quantify prognostic information based on imaging data alone or systemic factors alone, there are currently no large studies that quantify marginal prognostic information within a multivariate model, including both imaging and systemic factors.

Conclusion

With standard imaging techniques and ways of processing images rapidly evolving, an international network of centers is needed to routinely capture systemic health factors simultaneously to retinal images so that gains in prediction increment may be precisely quantified to determine the usefulness of various health factors in the prognosis of DRD and prediction of response to treatment.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Lack of association between month of birth and risk of developing type 1 diabetes in Brazil: a 40-year analysis

OBJECTIVES

Seasonal environment at birth may influence diabetes incidence in later life. We sought evidence for this effect and analyzed the association between the month of birth and the risk of developing type 1 diabetes mellitus (T1DM).

METHODS

This was a cohort study carried out with 814 patients diagnosed with T1DM in the region of Bauru - São Paulo State, Brazil, receiving medical care in a private Endocrinology clinic or in the public Brazilian National Health Care System, from 1981 to 2021. All live births that occurred in São Paulo State between 1974 and 2020 were classified by month of birth and were considered as the control group.

RESULTS

We found no statistically significant difference (χ2=16.31, critical 19.68) between the month of birth and risk of developing T1DM, when comparing our patients with the background population of the region. There was no association between the month of birth, sex, age at diagnosis, duration of symptoms before diagnosis, self-reported color, and socioeconomic status.

CONCLUSIONS

We found no association between month of birth and the risk of developing T1DM in this highly admixed South American population. Our data suggest that our population heterogeneity and geographic location may be important factors in the development of T1DM. Future prospective studies, evaluating environmental factors that may confer risk or protection to the disease, are warranted.

Serum MicroRNA-191-5p Levels in Vascular Complications of Type 1 Diabetes: The EURODIAB Prospective Complications Study

CONTEXT

MicroRNA-191-5p regulates key cellular processes involved in the pathogenesis of diabetic complications such as angiogenesis, extracellular matrix deposition, and inflammation. However, no data on circulating microRNA-191-5p in the chronic complications of diabetes are available.

OBJECTIVE

To assess whether serum levels of microRNA-191-5p were associated with micro- and macrovascular disease in a large cohort of subjects with type 1 diabetes mellitus (DM1) from the EURODIAB Prospective Complication Study.

DESIGN AND SETTING

Levels of microRNA-191-5p were measured by quantitative PCR in 420 patients with DM1 recruited as part of the cross-sectional analysis of the EURODIAB Prospective Complication Study. Cases (n = 277) were subjects with nephropathy and/or retinopathy and/or cardiovascular disease (CVD). Controls (n = 143) were patients without complications. Logistic regression analysis was performed to evaluate the potential independent association of microRNA-191-5p levels with chronic complications of diabetes.

RESULTS

Levels of microRNA-191-5p were significantly reduced (P < .001) in cases compared with controls even after adjustment for age, sex, and diabetes duration. Logistic regression analysis revealed that microRNA-191-5p was negatively associated with a 58% reduced odds ratio (OR) of chronic diabetes complications, specifically CVD, micro-macroalbuminuria, and retinopathy (OR, 0.42; 95% CI, 0.23-0.77), independent of age, sex, physical activity, educational levels, diabetes duration, glycated hemoglobin, total insulin dose, hypertension, smoking, total cholesterol, albumin excretion rate, estimated glomerular filtration rate, serum vascular cell adhesion molecule-1, and tumor necrosis factor-α. Analyses performed separately for each complication demonstrated a significant independent association with albuminuria (OR, 0.36; 95% CI, (0.18-0.75) and CVD (OR, 0.34; 95% CI, 0.16-0.70).

CONCLUSIONS

In DM1 subjects, microRNA-191-5p is inversely associated with vascular chronic complications of diabetes.

Association between the triglyceride glucose index and diabetic retinopathy in type 2 diabetes: a meta-analysis

The triglyceride-glucose (TyG) index is an accessible and reliable surrogate indicator of insulin resistance and is strongly associated with diabetes. However, its relationship with diabetic retinopathy (DR) remains controversial. This meta-analysis aimed to assess the relationship between the TyG index and the prevalence of DR. Initial studies were searched from PubMed, Embase, Web of Science, and China National Knowledge Infrastructure (CNKI) electronic databases. The retrieval time range was from the establishment of the database to June 2023. Pooled estimates were derived using a random-effects model and reported as odds ratio (OR) with 95% confidence intervals (CIs). Two researchers independently assessed the methodological quality of the included studies. The Newcastle-Ottawa Quality Scale (NOS) was utilized to assess cohort studies or case-control studies. The Agency for Healthcare Research and Quality (AHRQ) methodology checklist was applied to assess cross-sectional studies. Ten observational studies encompassing 13716 patients with type 2 diabetes were included in the meta-analysis. The results showed that a higher TyG index increased the risk of DR compared with a low TyG index (OR: 2.34, 95% CI: 1.31-4.19, P < 0.05). When the index was analyzed as a continuous variable, consistent results were observed (OR: 1.48, 95% CI: 1.12-1.97, P < 0.005). There was no significant effect on the results of the sensitivity analyses excluding one study at a time (P all < 0.05). A higher TyG index may be associated with an increased prevalence of DR in patients with type 2 diabetes. However, high-quality cohort or case-control studies are needed to further substantiate this evidence.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023432747.

Insulin Resistance in Adolescents and Youth With Type 1 Diabetes: A Review of Problems and Solutions

Though insulin resistance (IR) was previously considered a feature of only type 2 Diabetes (T2DM), its development in type 1 Diabetes (T1DM) is not an uncommon occurrence, the causes of which are multifactorial (gender, pubertal status, diabetes duration, ethnicity, genetics, adiposity, glycemic control, chronic inflammation). Despite improvements in glucose, blood pressure and lipid profile, vascular complications (coronary artery disease and nephropathy) continue to remain common causes of morbidity and mortality in T1DM. Aggressive glycemic control reduces but does not eliminate the risk of IR. IR accelerates the development of micro and macrovascular complications, many of which can be potentially reversed if diagnosed and managed early. Lack of endogenous insulin production makes estimation of insulin sensitivity in T1DM difficult. As hyperinsulinemic-euglycemic clamp studies are cumbersome and invasive, the use of prediction equations for calculating estimated insulin sensitivity may prove to be useful. Along with intensive insulin therapy, dietary modifications and increasing physical activity, the role of Metformin in managing IR in T1DM is becoming increasingly popular. Metformin adjunct therapy in T1DM has been shown to improve insulin sensitivity, glycemic control, lipid profile, body composition, vascular smooth muscle function, thereby reducing the risk of vascular complications, as well as reversal of early vascular dysfunction. However, further studies to assess long-term efficacy and safety of Metformin use in adolescents and youth with T1DM are needed. This review aims at revisiting the pathophysiology of IR in T1DM and techniques of identifying those at risk so as to put into action various strategies for management of the same.

Insulin resistance is more frequent in type 1 diabetes patients with long disease duration

AIMS

To investigate the clinical status of insulin resistance (IR) and its correlation with disease duration in patients with type 1 diabetes (T1D).

MATERIALS AND METHODS

Cross-sectional data from a T1D cohort were obtained (n = 923). IR-related metabolic disorders including hypertension, obesity, and dyslipidemia were used as outcome variables to explore the cut-off point for estimated glucose disposal rate (eGDR) by restricted cubic spline (RCS) curve. Regression models were used for multivariate analysis of the clinical factors associated with IR. The correlation between the status of IR and diabetes duration was depicted with the RCS curve.

RESULTS

IR-related metabolic disorders were observed in 39.4% of patients, with 9.1% meeting the criteria for metabolic syndrome. Specifically, patients with ≥10 years of T1D were more likely to have IR-related metabolic disorders (54.7% vs. 36.9%, p < 0.05). The presence of IR, defined as an eGDR ≤9.0 mg/kg/min, was observed in 42.2% of patients. Patients with IR had a longer diabetes duration (3.5 vs. 2.7, years, p = 0.003) and higher insulin dose (0.5 vs. 0.4, units per kg per day, p < 0.001). Moreover, the presence of IR showed a gradual increase during 10 years' disease duration and further analysis showed that diabetes duration ≥10 years was a key element behind the development of IR and IR-related metabolic disorders.

CONCLUSIONS

The status of IR is common in T1D patients, especially in those with ≥10 years of disease duration. Therapies targeting balancing glycaemic control and IR are needed to decrease the future risk of cardiovascular diseases in T1D.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT03610984 (cohort study of patients with type 1 diabetes).

Metabolic syndrome in patients with type 1 diabetes mellitus at a tertiary centre in North India: A five year follow up study

BACKGROUND AND AIMS

Metabolic syndrome (MS) is prevalent in the Indian population and has been traditionally linked to Type 2 diabetes mellitus (T2DM). Its presence is now being increasingly recognized in patients with Type 1 diabetes mellitus (T1DM). Presence of MS may increase the risk of diabetes related complications. This study was designed to determine the prevalence of MS in a cohort of patients with T1DM at baseline and at 5 years of follow up.

METHODS

Longitudinal cohort study in a tertiary care center in North India. Patients with T1DM attending the Diabetes of the Young (DOY) Clinic from January 2015 to March 2016 included. Microvascular and macrovascular complications assessed. The cohort was followed after a period of 5 years.

RESULTS

We included 161 patients (males, 49.4%) with a median (IQR) age of 23 (18-34) years and median (IQR) diabetes duration of 12 (7, 17) years. At baseline, 31 (19.2%) patients had MS. Patients with MS were more likely to have microvascular complications: retinopathy (p = 0.003), neuropathy (p = 0.02) and nephropathy (p = 0.04). Independent predictors of MS: insulin sensitivity (IS) (adjusted OR (aOR) 0.02 [95% CI, 0.003-0.118]), body weight (aOR 1.05 [95% CI, 1.007-1.108]), diastolic blood pressure (aOR 1.08 [95% CI, 1.01-1.15]) and duration of diabetes (aOR 1.09 [95% CI, 1.02-1.16]). On follow-up (n = 100), 13 (13%) had MS.

CONCLUSIONS

One in 5 patients with T1DM suffers from MS, and is therefore predisposed to its attendant risks, calling for early identification and targeted interventions.

Estimated glucose disposal rate is associated with retinopathy and kidney disease in young people with type 1 diabetes: a nationwide observational study

AIMS

The aim of this study was to investigate the association between estimated glucose disposal rate (eGDR), a proxy for insulin resistance, and retinopathy or kidney disease, i.e. micro-, or macroalbuminuria, in young individuals with type 1 diabetes (T1D).

MATERIAL AND METHODS

Using data from the Swedish pediatric registry for diabetes (SweDiabKids) and the registry for adults (NDR), all individuals with T1D with a duration of diabetes of less than 10 years between 1998 and 2017 were included. We calculated the crude incidence rates with 95% confidence intervals (CIs) and used multivariable Cox regression to estimate crude and adjusted hazard ratios (HRs) for two cohorts: retinopathy cohort or kidney disease cohort, stratified by eGDR categories: < 4, 4 to 5.99, 6 to 7.99, and ≥ 8 mg/kg/min (reference).

RESULTS

A total of 22 146 (10 289 retinopathy cohort, and 11 857 kidney disease cohort with an overlapping of 9575) children and adults with T1D (median age 21 years, female 42% and diabetes duration of 6 and 7 years, respectively for the cohorts) were studied. During a median follow-up of 4.8 years (IQR 2.6-7.7) there were 5040 (24.7%), 1909 (48.1%), 504 (52.3%) and 179 (57.6%) events for retinopathy in individuals with an eGDR ≥ 8, 7.99 to 6, 5.99 to 4, and < 4 mg/kg/min, respectively. Corresponding numbers for kidney disease was 1321 (6.5%), 526 (13.3%), 255 (26.8%) and 145 (46.6%). After multiple adjustments for different covariates, individuals with an eGDR 7.99 to 6, 5.99 to 4 and < 4 mg/kg/min, had an increased risk of retinopathy compared to those with an eGDR ≥ 8 mg/kg/min (adjusted HRs, 95% CIs) 1.29 (1.20 to 1.40); 1.50 (1.31 to 1.71) and 1.74 (1.41 to 2.14). Corresponding numbers for kidney disease was (adjusted HRs, 95% CIs) 1.30 (1.11 to 1.52); 1.58 (1.25 to 1.99) and 1.33 (0.95 to 1.86), respectively.

CONCLUSIONS

eGDR, a proxy for insulin resistance, is associated with retinopathy and kidney disease in young adults with T1D. The risk of retinopathy increased with lower eGDR. The risk of kidney disease also increased with lower eGDR; however results show no association between the lowest eGDR and kidney disease. eGDR can be helpful to identify young T1D individuals at risk.

Prevalence of overweight/obesity and its relationship with metabolic syndrome and fatty liver index in adult patients with type 1 diabetes. A Brazilian multicenter study

AIMS

To determine the prevalence of overweight/obesity and its relationship with metabolic syndrome (MS), fatty liver index (FLI), cardiovascular risk factors (CVRF), and diabetes-related chronic complications (DRCC) in adult patients with type 1 diabetes (T1D).

METHODS

This study was conducted in 14 Brazilian public clinics in ten cities, with 1,390 patients: 802 females (57.7%), 779 (56.0%) Caucasians, aged 33.6 ± 10.8 years, age at diagnosis, 16.2 ± 9.2 years, diabetes duration, 17.4 ± 9.2 years, and HbA1c 8.8 ± 2.0%.

RESULTS

Overall, 825 patients (59.4%) had normal weight, and 565 had overweight/obesity; ( 429 (30.9%) presented overweight and 136 (9.8%) presented obesity). After adjustments, overweight/obesity was associated with age, family history of overweight/obesity, total daily insulin dose, hypertension, adherence to diet, type of health care insurance, use of metformin, levels of C-reactive protein, triglycerides, uric acid and HDL-cholesterol. These patients also presented a higher prevalence of MS, FLI ≥ 60, and CVRF than patients without overweight/obesity. Overweight/obesity was not associated with DRCC and with HbA1c levels.

CONCLUSIONS

Patients with T1D with overweight/obesity presented traditional risk factors for DRCC, cardiovascular diseases, MS, and non-alcoholic fatty liver disease; most of these risk factors are modifiable and can be avoided with interventions that prevent overweight/obesity.

Sex-Related Effects of Gut Microbiota in Metabolic Syndrome-Related Diabetic Retinopathy

The metabolic syndrome (MetS) is a complex disease of metabolic abnormalities, including obesity, insulin resistance, hypertension and dyslipidaemia, and it is associated with an increased risk of cardiovascular disease (CVD). Diabetic retinopathy (DR) is the leading cause of vision loss among working-aged adults around the world and is the most frequent complication in type 2 diabetic (T2D) patients. The gut microbiota are a complex ecosystem made up of more than 100 trillion of microbial cells and their composition and diversity have been identified as potential risk factors for the development of several metabolic disorders, including MetS, T2D, DR and CVD. Biomarkers are used to monitor or analyse biological processes, therapeutic responses, as well as for the early detection of pathogenic disorders. Here, we discuss molecular mechanisms underlying MetS, the effects of biological sex in MetS-related DR and gut microbiota, as well as the latest advances in biomarker research in the field. We conclude that sex may play an important role in gut microbiota influencing MetS-related DR.

Association of parental cardiovascular risk factors with offspring type 1 diabetes mellitus insulin sensitivity

AIM

This study aimed to determine whether the insulin resistance (IR) and lipid profiles in Type 1 Diabetes (T1D) offspring are associated with IR and other cardiovascular risk factors in their parents.

METHODS

This study included 99 T1D patients (19.6 ± 4.0 yrs.), 85 mothers and 60 fathers. Parents' IR was assessed by HOMA-IR, and the insulin sensitivity in T1D patients was assessed by the estimated Glucose Disposal Rate (eGDR).

RESULTS

The eGDR in the T1D offspring was negatively related to age (p = 0.023), weight (p = 0.004), LDL (p = 0.026), and microalbuminuria (p = 0.019). Maternal Type 2 Diabetes (p < 0.001) and HOMA-IR (p = 0.029) were negatively related to eGDR in their T1D offspring. The maternal HOMA-IR and the proband's eGDR were positively (p = 0.012) and negatively (p = 0.042) associated with the birth weight of the T1D offspring, respectively. We didn't find an association with the fathers' profiles.

CONCLUSIONS

In a cohort of offspring with T1D the insulin sensitivity was related to the IR, lipid profile, and the presence of T2D only in their mothers. Precocious screening and treatment of these risk factors beyond glycemic control will benefit T1D with this background.

Association between abdominal obesity and diabetic retinopathy in patients with diabetes mellitus: A systematic review and meta-analysis

OBJECTIVE

Previous studies have reported different opinions regarding the association between abdominal obesity and diabetic retinopathy (DR) in patients with diabetes mellitus (DM). In this study, we aimed to investigate this problem through a systematic review and meta-analysis to provide a basis for clinical interventions.

METHODS

A comprehensive search was conducted in the PubMed, Embase, and Web of Science databases up to May 1, 2022, for all eligible observational studies. Standardized mean differences (SMD) and 95% confidence intervals (CI) were evaluated using a random-effects model in the Stata software. We then conducted, publication bias assessment, heterogeneity, subgroup and sensitivity analyses.

RESULTS

A total of 5596 DR patients and 17907 non-DR patients were included from 24 studies. The results of the meta-analysis of abdominal obesity parameters showed statistically significant differences between DR and non-DR patients in both type 1 and type 2 diabetes. Waist circumference (WC) was higher in patients with DR than in the non-DR patients. In the waist-hip ratio (WHR) subgroup, the level of WHR was higher in patients with DR than that in non-DR patients. The association between abdominal obesity and mild to moderate nonproliferative DR or vision-threatening DR groups did not show any statistical difference. Subgroup analysis according to ethnicity showed that Caucasians had higher levels of combined abdominal obesity parameters than Asians.

CONCLUSION

We found that abdominal obesity measured by WC and WHR is associated with DR in patients with type 1 and type 2 diabetes. This association is stronger in Caucasians than in Asians, where isolated abdominal obesity might be more related to DR. However, no correlation was found between abdominal obesity and varying degrees of diabetic retinopathy. Further prospective cohort studies with larger sample sizes are yet to be conducted to clarify our findings.

Relationship Between Estimated Glucose Disposal Rate and Type 2 Diabetic Retinopathy

PURPOSE

To investigate the association between diabetic retinopathy (DR), DR intensity, and estimated glucose disposal rate (eGDR) in individuals with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

This study comprised 1762 T2DM patients who were admitted between January and December, 2021. Overall, the DR was identified in 430 patients. Based on the eGDR, the participants were divided into four study groups. One-way analysis of variance was used to compare the groups. The correlations between eGDR and DR risk, eGDR, and DR severity were analyzed using regression analysis. Furthermore, these relationships were analyzed in different sex groups.

RESULTS

Patients with T2DM had a 19.75% (348/1762) DR detection rate, whereas those with DR had a 22.41% (78/348) proliferative DR detection rate. The DR group had substantially reduced levels of eGDR compared with the non-DR group. Multivariate logistic regression analysis demonstrated that reduced eGDR was an independent risk factor for DR, after adjusting for confounding variables. eGDR correlated significantly with proliferative DR in women but not in men.

CONCLUSION

In Chinese individuals with T2DM, lower eGDR was independently associated with a higher risk of DR.

Association of serum MicroRNA-145-5p levels with microvascular complications of type 1 Diabetes: The EURODIAB prospective complications study

AIMS

To investigate whether serum miR-145-5p levels were associated with micro-macrovascular chronic complications in patients with type 1 diabetes (DM1).

METHODS

A nested case-control study from the EURODIAB Prospective Complications Study was performed. Cases (n = 289) had one or more complications of diabetes, whereas controls (n = 153) did not have any complication. We measured miR-145-5p levels by qPCR and investigated the association with diabetes complications.

RESULTS

Mean miR-145-5p levels were significantly lower in cases with microangiopathy [2.12 (0.86-4.94)] compared to controls [3.15 (1.21-7.36), P < 0.05] even after adjustment for age, gender, and diabetes duration. In logistic regression analysis, miR-145-5p levels in the lowest tertile were associated with an over three-fold increased odds ratio (OR) of albuminuria [3.22 (1.17-8.81)], independently of both demographic and diabetes-related factors. In addition, mir145-5p levels in the lowest tertile were independently and inversely associated with arterial hypertension [1.96 (1.08-3.56)] and hypertension was the mediator of the relationship between miR-145-5p and albuminuria.

CONCLUSIONS

In this large cohort of DM1 patients, we found an inverse association between miR-145-5p and albuminuria that was mediated by systemic hypertension.

Changes of insulin resistance status and development of complications in type 1 diabetes mellitus: Analysis of DCCT/EDIC study

AIM

There is no longitudinal study regarding the changes of insulin resistance (IR) status and the development of complications in type 1 diabetes (T1D). By analyzing data sets from DCCT/EDIC study, we investigated the associations of IR status changes and diabetic complications in T1D.

MATERIALS AND METHODS

Estimated glucose disposal rate (eGDR) was calculated at entry of DCCT and in EDIC year 12 (average 18.5 years later) to represent IR. The participants (n = 957) were divided into four groups based on IR changes from baseline: RR group (stayed resistant; n = 49), RS group (became sensitive; n = 42), SR group (became resistant; n = 197), and SS group (stayed sensitive; n = 669). The association of diabetic complications were analyzed by using multivariable logistic regression models.

RESULTS

The improved IR decreased the risk of peripheral neuropathy, whereas the deteriorated IR increased the risk of diabetic complications including hypertension, peripheral artery disease, coronary artery calcification, retinopathy, albuminuria, peripheral neuropathy, and cardiac autonomic neuropathy (P < 0.05). Moreover, RR group (HR = 3.59, 95% CI (2.05-6.32)), RS group (HR = 2.27, 95% CI (1.11-4.64)) and SR group (HR = 1.90, 95% CI (1.24-2.92)) had higher risk of cardiovascular events compared to SS group (P < 0.05).

CONCLUSIONS

This study highlights the importance of IR changes represented by eGDR in the development of diabetic complications. Patients with T1D and IR may require intensive therapy.

Overweight/obesity in adolescents with type 1 diabetes belonging to an admixed population. A Brazilian multicenter study

BACKGROUND

To determine the prevalence of overweight/obesity and associated risk factors in Brazilian adolescents with type 1 diabetes (T1D) and its association with diabetic retinopathy (DR) and chronic kidney disease (CKD).

METHODS

This study was performed in 14 Brazilian public clinics in ten cities, with 1,760 patients. 367 were adolescents (20.9%):184 females (50.1%), 176 (48.0%) Caucasians, aged 16.4 ± 1.9 years, age at diagnosis 8.9 ± 4.3 years, diabetes duration 8.1 ± 4.3 years, school attendance 10.9 ± 2.5 years and HbA1c 9.6 ± 2.4%.

RESULTS

95 (25.9%) patients presented overweight/obesity, mostly females. These patients were older, had longer diabetes duration, higher levels of total and LDL-cholesterol, higher prevalence of family history of hypertension, hypertension, undesirable levels of LDL-cholesterol, and metabolic syndrome compared to eutrophic patients. No difference was found regarding ethnicity, HbA1c, uric acid, laboratorial markers of non-alcoholic fatty liver disease (alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase).

CONCLUSIONS

Almost one quarter of our patients presented overweight/obesity. These patients had higher prevalence of traditional risk factors for micro and macrovascular diabetes-related chronic complications such as diabetes duration, hypertension, high levels of LDL-cholesterol and metabolic syndrome. The majority of the patients with or without overweight/obesity presented inadequate glycemic control which is also an important risk factor for micro and macrovascular diabetes-related chronic complications. No association was found between overweight/obesity with diabetic CKD, DR and laboratorial markers of non-alcoholic fatty liver disease. The above-mentioned data point out that further prospective studies are urgently needed to establish the clinical prognosis of these young patients.

Diabetic retinopathy risk in patients with unhealthy lifestyle: A Mendelian randomization study

PURPOSE

This study aimed to investigate the causal association between unhealthy lifestyle factors and diabetic retinopathy (DR) risk and to determine better interventions targeting these modifiable unhealthy factors.

DESIGN

Two-sample Mendelian randomization (MR) analysis was performed in this study. The inverse variance-weighted method was used as the primary method.

METHOD

Our study included 687 single-nucleotide polymorphisms associated with unhealthy lifestyle factors as instrumental variables. Aggregated data on individual-level genetic information were obtained from the corresponding studies and consortia. A total of 292,622,3 cases and 739,241,18 variants from four large consortia (MRC Integrative Epidemiology Unit [MRC-IEU], Genetic Investigation of Anthropometric Traits [GIANT], GWAS & Sequencing Consortium of Alcohol and Nicotine Use [GSCAN], and Neale Lab) were included.

RESULT

In the MR analysis, a higher body mass index (BMI) (odds ratio [OR], 95% confidence interval [CI] = 1.42, 1.30-1.54; P < 0.001] and cigarettes per day (OR, 95% CI = 1.16, 1.05-1.28; P = 0.003) were genetically predicted to be causally associated with an increased risk of DR, while patients with higher hip circumference (HC) had a lower risk of DR (OR, 95% CI = 0.85, 0.76-0.95; P = 0.004). In the analysis of subtypes of DR, the results of BMI and HC were similar to those of DR, whereas cigarettes per day were only related to proliferative DR (PDR) (OR, 95% CI = 1.18, 1.04-1.33; P = 0.009). In the MR-PRESSO analysis, a higher waist-to-hip ratio (WHR) was a risk factor for DR and PDR (OR, 95% CI = 1.24, 1.02-1.50, P = 0.041; OR, 95% CI = 1.32, 1.01-1.73, P = 0.049) after removing the outliers. Furthermore, no pleiotropy was observed in these exposures.

CONCLUSION

Our findings suggest that higher BMI, WHR, and smoking are likely to be causal factors in the development of DR, whereas genetically higher HC is associated with a lower risk of DR, providing insights into a better understanding of the etiology and prevention of DR.

MicroRNA 146a is associated with diabetic complications in type 1 diabetic patients from the EURODIAB PCS

Background

MicroRNA-146a-5p (miR-146a-5p) is a key regulator of inflammatory processes. Expression of miR-146a-5p is altered in target organs of diabetic complications and deficiency of miR-146a-5p has been implicated in their pathogenesis. We investigated if serum miR-146a-5p levels were independently associated with micro/macrovascular complications of type 1 diabetes (DM1).

Methods

A nested case–control study from the EURODIAB PCS of 447 DM1 patients was performed. Cases (n = 294) had one or more complications of diabetes, whereas controls (n = 153) did not have any complication. Total RNA was isolated from all subjects and miR-146a-5p levels measured by qPCR. Both the endogenous controls U6 snRNA and the spike (Cel-miR-39) were used to normalize the results. Logistic regression analysis was carried out to investigate the association of miR-146a-5p with diabetes complications.

Results

MiR-146a-5p levels were significantly lower in cases [1.15 (0.32–3.34)] compared to controls [1.74 (0.44–6.74) P = 0.039]. Logistic regression analysis showed that levels of miR-146a-5p in the upper quartile were inversely associated with reduced odds ratio (OR) of all complications (OR 0.34 [95% CI 0.14–0.76]) and particularly with cardiovascular diseases (CVD) (OR 0.31 [95% CI 0.11–0.84]) and diabetic retinopathy (OR 0.40 [95% CI 0.16–0.99]), independently of age, sex, diabetes duration, A1c, hypertension, AER, eGFR, NT-proBNP, and TNF-α.

Conclusions

In this large cohort of DM1 patients, we reported an inverse and independent association of miR-146a-5p with diabetes chronic complications and in particular with CVD and retinopathy, suggesting that miR-146a-5p may be a novel candidate biomarker of DM1 complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03142-4.

Estimated glucose disposal rate as a candidate biomarker for thrombotic biomarkers in T1D: a pooled analysis

PURPOSE

To determine the utility of estimated glucose disposal rate (eGDR) as a candidate biomarker for thrombotic biomarkers in patients with type 1 diabetes (T1D).

METHODS

We reanalysed baseline pretreatment data in a subset of patients with T1D from two previous RCTs, consisting of a panel of thrombotic markers, including fibrinogen, tissue factor (TF) activity, and plasminogen-activator inhibitor (PAI)-1, and TNFα, and clinical factors (age, T1D duration, HbA1c, insulin requirements, BMI, blood pressure, and eGDR). We employed univariate linear regression models to investigate associations between clinical parameters and eGDR with thrombotic biomarkers.

RESULTS

Thirty-two patients were included [mean ± SD age 31 ± 7 years, HbA1c of 58 ± 9 mmol/mol (7.5 ± 0.8%), eGDR 7.73 ± 2.61]. eGDR negatively associated with fibrinogen (P < 0.001), PAI-1 concentrations (P = 0.005), and TF activity (P = 0.020), but not TNFα levels (P = 0.881). We identified 2 clusters of patients displaying significantly different characteristics; 56% (n = 18) were categorised as 'higher-risk', eliciting significantly higher fibrinogen (+ 1514 ± 594 μg/mL; P < 0.001), TF activity (+ 59.23 ± 9.42 pmol/mL; P < 0.001), and PAI-1 (+ 8.48 ± 1.58 pmol/dL; P < 0.001), HbA1c concentrations (+ 14.20 ± 1.04 mmol/mol; P < 0.001), age (+ 7 ± 3 years; P < 0.001), duration of diabetes (15 ± 2 years; P < 0.001), BMI (+ 7.66 ± 2.61 kg/m²; P < 0.001), and lower mean eGDR (- 3.98 ± 1.07; P < 0.001).

CONCLUSIONS

Compared to BMI and insulin requirements, classical surrogates of insulin resistance, eGDR is a suitable and superior thrombotic risk indicator in T1D.

TRIAL REGISTRATION

ISRCTN4081115; registered 27 June 2017.

Prevalence, severity stages, and risk factors of diabetic retinopathy in 1464 adult patients with type 1 diabetes

PURPOSE

To determine the prevalence of diabetic retinopathy (DR) and its risk factors in adult type 1 diabetes (T1D) patients METHODS: In this cross-sectional study, all T1D patients followed in the University Center for Diabetes and its Complications of Lariboisière Hospital (Paris, France) between January 2017 and February 2019 were included. Ophthalmologic and systemic data were collected from electronic records. The association between DR (and each grade) and associated factors were estimated by univariate and multivariate analyses using logistic regression models.

RESULTS

A total of 1464 patients (46.2% of women, mean age: 42.2 ± 15.8 years) were included. The mean hemoglobin A1c (HbA1c) was 7.8 ± 1.7% and the mean diabetes duration was 20.5 ± 13.5 years. DR prevalence was 50.1% (47.4-52.6) and the prevalence of mild, moderate, and severe non-proliferative DR and proliferative DR was 19.1%, 9.4%, 3.9%, and 17.6%, respectively. DR was significantly associated with male gender, an older age, former and current smoking status, a higher BMI, the presence of nephropathy and neuropathy, higher HBA1c, and longer diabetes duration. Patients with HbA1c > 10% had an adjusted odds ratio (OR) of 3.25 (1.77-6.01) of having DR compared to patients with HbA1c < 6.5%. Patients with a diabetes duration > 30 years had an adjusted OR of 24.87 (14.82-42.67) higher of having DR compared to patients with a diabetes duration < 10 years.

CONCLUSION

In this study, 50.1% of adult T1D patients had DR and 17.6% had proliferative DR. Diabetes duration and HbA1c were major risk factors.

Diabetic retinopathy in the Eastern Morocco: Different stage frequencies and associated risk factors

Diabetes is a major cause of morbidity and mortality worldwide. It can affect many organs and, over time, leads to serious complications. Diabetic retinopathy (DR), a specific ocular complication of diabetes, remains the leading cause of vision loss and vision impairment in adults. This work is the first in Eastern Morocco aimed at identifying the different stages of DR and to determine their frequencies and associated risk factors. It is a case-control study conducted from December 2018 to July 2019 at the ophthalmology department of Al-Irfane Clinic (Oujda). Data were obtained from a specific questionnaire involving 244 diabetic patients (122 cases with retinopathy vs 122 controls without retinopathy). All results were analyzed by the EPI-Info software. This study shows a predominance of proliferative diabetic retinopathy (PDR) with 57.4% of cases (uncomplicated proliferative diabetic retinopathy (UPDR): 23.8%; complicated proliferative diabetic retinopathy (CPDR): 33.6%). The non-proliferative diabetic retinopathy (NPDR) represents 42.6% (minimal NPDR: 8.2%; moderate NPDR: 26.2%; severe NPDR: 8.2%). The determinants of DR were insulin therapy, high blood pressure, poor glycemic control and duration of diabetes. Regarding the chronological evolution, retinopathy precedes nephropathy. Diabetic nephropathy (DN) was present in 10.6% of cases especially in patients with PDR. In summary, the frequency of PDR was higher than that of NPDR. DR appears before DN with a high frequency of DN in patients with PDR. Good glycemic control and blood pressure control, as well as early diagnosis are the major preventive measures against DR.

A Human Randomized Controlled Trial Comparing Metabolic Responses to Single and Repeated Hypoglycemia in Type 1 Diabetes

AIMS

Hypoglycemia hinders optimal glycemic management in type 1 diabetes (T1D). Long diabetes duration and hypoglycemia impair hormonal counter-regulatory responses to hypoglycemia. Our study was designed to test whether (1) the metabolic responses and insulin sensitivity are impaired, and (2) whether they are affected by short-lived antecedent hypoglycemia in participants with T1D.

MATERIALS AND METHODS

In a randomized, crossover, 2x2 factorial design, 9 male participants with T1D and 9 comparable control participants underwent 30 minutes of hypoglycemia (p-glucose < 2.9 mmol/L) followed by a euglycemic clamp on 2 separate interventions: with and without 30 minutes of hypoglycemia the day before the study day.

RESULTS

During both interventions insulin sensitivity was consistently lower, while counter-regulatory hormones were reduced, with 75% lower glucagon and 50% lower epinephrine during hypoglycemia in participants with T1D, who also displayed 40% lower lactate and 5- to 10-fold increased ketone body concentrations following hypoglycemia, whereas palmitate and glucose turnover, forearm glucose uptake, and substrate oxidation did not differ between the groups. In participants with T1D, adipose tissue phosphatase and tensin homolog (PTEN) content, hormone-sensitive lipase (HSL) phosphorylation, and muscle glucose transporter type 4 (GLUT4) content were decreased compared with controls. And antecedent hypoglycemic episodes lasting 30 minutes did not affect counter-regulation or insulin sensitivity.

CONCLUSIONS

Participants with T1D displayed insulin resistance and impaired hormonal counter-regulation during hypoglycemia, whereas glucose and fatty acid fluxes were intact and ketogenic responses were amplified. We observed subtle alterations of intracellular signaling and no effect of short-lived antecedent hypoglycemia on subsequent counter-regulation. This plausibly reflects the presence of insulin resistance and implies that T1D is a condition with defective hormonal but preserved metabolic responsiveness to short-lived hypoglycemia.

Insulin resistance is associated with preclinical carotid atherosclerosis in patients with type 1 diabetes

AIM

Although insulin resistance (IR) is a growing trait among type 1 diabetes (T1D) population, its relationship with atherosclerosis has been scarcely studied. We assessed the association between IR indexes and carotid atherosclerosis in T1D, a population at high cardiovascular disease (CVD) risk.

MATERIALS AND METHODS

We evaluated 191 participants with T1D and no prior CVD with at least one of the following criteria: ≥40 years old; diabetic nephropathy; or T1D duration ≥10 years harbouring ≥1 additional CVD risk factor. IR was assessed with the metabolic syndrome (MetS) harmonized definition proposed in 2009 and the estimated glucose disposal rate (eGDR), a T1D-specific IR surrogate marker (lower values indicating higher IR). Standardized carotid ultrasonography was performed, recording intima-media thickness (IMT), plaque presence and maximum height of plaque. Comparisons between patients according to their MetS status as well as concerning eGDR values were performed.

RESULTS

The participants' median age was 47.4 (41.1-53.3) years and diabetes duration 25.7 (21.6-32.5) years. Plaque prevalence was higher in patients with greater IR (49.1%, 29.1% and 20%, P = .001, for any plaque according to decreasing eGDR tertiles). Conversely, no statistically significant higher plaque prevalence was found in participants with MetS. In multivariate analyses (adjusted for general- and T1D-specific risk factors, and statin treatment), MetS was associated with neither IMT nor plaque. On the contrary, eGDR was independently related to ≥2 plaques (P = .018) and maximum plaque height (P < .01).

CONCLUSIONS

In T1D, IR assessed through eGDR but not by MetS definition was independently associated with plaque burden, a predictor of CVD.

Vascular and metabolic effects of metformin added to insulin therapy in patients with type 1 diabetes: A systematic review and meta-analysis

BACKGROUND

The incidence of type 1 diabetes mellitus (T1DM) is increasing among youth worldwide, translating to an increased risk ofearly-onset cardiovascular disease (CVD). Mounting studies have shown that metformin may reduce maximal carotidintima-media thickness (cIMT), improve insulin resistance and metabolic control in subjects with T1DM, and thus, may extend cardioprotective benefits. This systematic review and meta-analysis was performed to assess the efficacy and safety of metformin added to insulin therapy on reducing CVD risks and improving metabolism in T1DM.

METHODS

PubMed, EMBASE, and the Cochrane Library were systematically searched for randomized controlled trials (RCTs) that compared metformin and insulin combination (duration ≥3 months) to insulin treatment alone in T1DM. Data were expressed as weighted/standardized mean differences (MDs/SMDs) for continuous outcomes and risk ratios (RRs) for dichotomous outcomes, along with 95% confidence intervals (CIs). The Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to evaluate the overall certainty of the evidence.

RESULTS

Nineteen RCTs (n = 1540) met the eligibility criteria. Metformin treatment significantly reduced carotid artery intima-media thickness (MD -0.06 mm [95% CI -0.88, -0.28], P < .001). Though no significant difference was found in insulin sensitivity (SMD 2.21 [95% CI -1.88, 6.29], P = .29), the total daily insulin dosage (SMD -0.81 [95% CI -1.25, -0.36], P < .001) along with traditional CVD risk factors showed improvement by better glycaemic control, partial lipid profiles, diastolic blood pressure, and limited weight gain, with neutral effect on diabetic ketoacidosis, lactic acidosis, and hypoglycaemia. However, metformin therapy increased the incidence of gastrointestinal adverse events.

CONCLUSIONS

Metformin with insulin has the potential to retard the progression of atherosclerosis and provides better metabolic control in patients with T1DM, and thus, providing a potential therapeutic strategy for patients with T1DM on reducing CVD risks.

Utility of estimated glucose disposal rate for predicting metabolic syndrome in children and adolescents with type-1 diabetes

Objectives To determine the clinical utility of the estimated glucose disposal rate (eGDR) for predicting metabolic syndrome (MetS) in children and adolescents with type-1 diabetes (T1D). Methods Modified criteria of the International Diabetes Federation were used to determine MetS in children and adolescents between 10 and 18 years of age with T1D. The eGDR, a validated marker of insulin sensitivity, was calculated in two different ways using either the waist-to-hip ratio (WHR) or waist circumference (WC). Receiver operating characteristic (ROC) curve analysis was performed to ascertain cut-off levels of the eGDR to predict MetS. Results A total of 200 patients (52% male) with T1D were enrolled in the study. The prevalence of MetS was 10.5% (n: 21). Lower eGDR levels, indicating greater insulin resistance, were found in T1D patients with MetS when compared to those without (6.41 ± 1.86 vs. 9.50 ± 1.34 mg/kg/min) (p < 0.001). An eGDRWHR cut-off of 8.44 mg/kg/min showed 85.7% sensitivity and 82.6% specificity, while an eGDRWC cut-off of 8.16 mg/kg/min showed 76.1% sensitivity and 92.1% specificity for MetS diagnosis. The diagnostic odds ratio was 28.6 (7.3-131.0) for the eGDRWHR cut-off and 37.7 (10.8-140.8) for the eGDRWC cut-off. Conclusions The eGDR is a mathematical formula that can be used in clinical practice to detect the existence of MetS in children and adolescents with T1D using only the WC, existence of hypertension, and hemoglobin A1c levels. An eGDR calculated using the WC could be a preferred choice due to its higher diagnostic performance.

Comparison of indirect markers of insulin resistance in adult patients with Double Diabetes

BACKGROUND

The presence of insulin resistance (IR) and metabolic syndrome (MS) in patients with type 1 diabetes (T1D) has been called "double diabetes". This entity increases the risk for development of micro and macrovascular complications and cardiovascular mortality. The gold standard for IR quantification is the hyperinsulinemic euglycemic clamp (HEC) but it is invasive, time-consuming and not available in the majority of the clinical settings. Because of this, some formulas for IR quantification have been proposed. We aimed to compare the utility of those methods for MS detection in patients with T1D.

METHODS

We conducted a cross-sectional study in 112 patients with T1D and determined the presence of MS using the Joint Statement Criteria. We calculated the estimated glucose disposal rate (eGDR), estimated insulin sensitivity index (eIS), natural logarithm of glucose disposal rate (lnGDR), triglyceride/high-density lipoprotein cholesterol ratio (TG/HDL-c), visceral adipose index (VAI) and waist-to-height ratio (WHtR), and compared among patients with and without MS using Student t-test or Mann-Whitney U test. Receiver Operating Characteristics curves for the different indexes were used to identify the best cut-off points for MS detection.

RESULTS

Thirty three percent of the patients were considered to have MS. The patients with MS had lower eGDR (5.49 [4.37-6.80] vs. 8.93 [8.03-9.94] mg/kg/min), eIS (2.89 [1.54-3.54] vs. 3.51 [2.68-4.68]) and lnGDR (1.69 ± 0.27 vs. 1.95 ± 0.21 mg/kg/min), and higher WHtR (0.55 ± 0.05 vs. 0.50 ± 0.05), VAI (3.4 [1.92-5.70] vs. 1.39 [0.97-1.92]) and TG/HDL-c (3.78 [2.63-5.73] vs. 1.77 [1.18-2.75]) in comparison with patients without MS. The cut-off points of TG-HDL-c > 2.0, eGDR < 7.32 mg/kg/min, lnGDR < 1.8 mg/kg/min, VAI > 1.84, WHtR > 0.52 and eIS < 2.92 had a sensitivity of 86, 85, 82, 77 and 70% respectively, for MS detection. The TG/HDL-c, lnGDR and eIS sensitivity changed depending on sex meanwhile eGDR, WHtR and VAI did not need adjust by sex.

CONCLUSION

Our data show that an eGDR < 7.32 mg/kg/min have the highest sensitivity and specificity to detect the presence of MS in patients with T1D.

Insulin Resistance in Type 1 Diabetes Mellitus and Its Association with Patient's Micro- and Macrovascular Complications, Sex Hormones, and Other Clinical Data

INTRODUCTION

The main objective of this research was to evaluate the association of insulin resistance (IR) with micro- and macrovascular complications, sex hormones, and other clinical data.

METHODS

Cross-sectional study of patients older than 18 years old with type 1 diabetes mellitus (T1DM) was performed. Participants filled in questionnaires about T1D, disease duration, smoking, glycemic control, chronic diabetes complications, and hypertension status. Data about chronic diabetic complications (neuropathy, retinopathy, and nephropathy) were collected from medical records. History of major cardiovascular events such as angina, myocardial infarction, and stroke were collected from medical records also. Laboratory tests including creatinine, cholesterol levels, testosterone (T), sex hormone-binding globulin (SHBG), estradiol levels, and albumin in 24-h urine sample were performed. IR was calculated using the following formula: estimated glucose disposal rate (eGDR) = 24.31 - [12.22 × waist-to-hip ratio (WHR)] - [3.29 ×  hypertension status (defined as 0 = no, 1 = yes)] - [0.57 × glycated hemoglobin (HbA1c)]. The data was considered statistically significant at p < 0.05.

RESULTS

A total of 200 people (mean age 39.9 ± 12.1 years) with T1D were included in the study. Patients with T1D were analyzed according to eGDR levels stratified by tertiles. The cutoff value of eGDR which reflects IR was less than 6.4 mg kg-1 min-1. When eGDR was less than 6.4 mg kg-1 min-1, diabetes microvascular complications occurred significantly more often (p < 0.001); the cutoff of eGDR for cardiovascular disease (CVD) events was less than 2.34 mg kg-1 min-1. Lower eGDR, longer diabetes duration, and lower HbA1c significantly increased CVD outcomes risk. eGDR was also significantly lower in smokers (7.3 ± 2.5 vs. non-smokers 8.2 ± 2.6, p = 0.011), the obese (lean 8.25 ± 2.47 vs. obese 5.36 ± 2.74, p < 0.000), older patients (less than 50 years 8.0 ± 2.5 vs. more than 50 years 6.2 ± 2.8, p = 0.001), men (men 6.4 ± 2.4 vs. women 8.7 ± 2.2, p < 0.001), patients with long-standing diabetes (< 10 years 7.3 ± 2.6 vs. > 10 years 8.7 ± 2.3, p < 0.001), and chronic diabetes complications (diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, p < 0.001), and patients with CVD (with CVD 5.5 ± 2.4 vs. no CVD 8.0 ± 2.4, p < 0.001). Patients with T1D and a family history of T2D were not susceptible to weight gain during intensive insulin treatment. Metabolic syndrome (MS) phenotype prevalence, including and dyslipidemia rate, were higher in the obese group than in normal weight, but a clear difference was not seen (p = 0.07). Positive linear correlation between men's T and eGDR level was observed (r = 0.33, p = 0.04), i.e., men with higher testosterone level had better insulin sensitivity. Other parameters (like T in women, estrogens, SHBG) did not show any significant association with eGDR.

CONCLUSIONS

According to stratified eGDR, IR was found for one-third of the current T1D population. Insulin resistant patients more frequently had microvascular complications and CVD events. Lower eGDR, longer diabetes duration, and lower HbA1c significantly increased CVD outcomes risk. IR was related to smoking, obesity, gender, age, and diabetes duration. Moreover, men's testosterone had a positive correlation with IR in T1D. Finally, patients with T1D and a positive family history of T2D were not susceptible to weight gain, while MS metabolic phenotype prevalence tended to be higher in obese than in lean patients with T1D, with a tendency to significant difference.

Carbohydrate Restriction in Type 1 Diabetes: A Realistic Therapy for Improved Glycaemic Control and Athletic Performance?

Around 80% of individuals with Type 1 diabetes (T1D) in the United States do not achieve glycaemic targets and the prevalence of comorbidities suggests that novel therapeutic strategies, including lifestyle modification, are needed. Current nutrition guidelines suggest a flexible approach to carbohydrate intake matched with intensive insulin therapy. These guidelines are designed to facilitate greater freedom around nutritional choices but they may lead to higher caloric intakes and potentially unhealthy eating patterns that are contributing to the high prevalence of obesity and metabolic syndrome in people with T1D. Low carbohydrate diets (LCD; <130 g/day) may represent a means to improve glycaemic control and metabolic health in people with T1D. Regular recreational exercise or achieving a high level of athletic performance is important for many living with T1D. Research conducted on people without T1D suggests that training with reduced carbohydrate availability (often termed "train low") enhances metabolic adaptation compared to training with normal or high carbohydrate availability. However, these "train low" practices have not been tested in athletes with T1D. This review aims to investigate the known pros and cons of LCDs as a potentially effective, achievable, and safe therapy to improve glycaemic control and metabolic health in people with T1D. Secondly, we discuss the potential for low, restricted, or periodised carbohydrate diets in athletes with T1D.

Insulin Resistance in Adults with Type 1 Diabetes is Associated with Lower Vitamin D Serum Concentration

AIM

Type 1 diabetes mellitus (T1DM) is a disease characterized by an absolute deficiency of endogenous insulin secretion. Insulin resistance (IR) may develop among patients with T1DM. Vitamin D deficiency was reported to be a risk factor in the development of IR. The aim of the study was to assess the relationship between serum concentrations of 25-hydroxyvitamin D (25(OH)D) and IR among patients with T1DM.

METHODS

The test group consisted of 110 adult patients [males=65 (59%)] with T1DM. Participants were recruited in Poland between 1^st October and 30^th April in 2015/2016 and 2016/2017. VD serum level was assessed by ELISA array. IR was assessed by estimated Glucose Disposal Rate (eGDR).

RESULTS

In the study group 21 (19%) patients were recognized as IR according to eGDR cut-offs (<7.5 mg/kg/min), 52 (47.3%) patients had VD deficiency (25(OH)D<20 ng/ml), 16 (14.5%) patients had 25(OH)D<10 ng/ml. Only 6 (5%) participants reported VD supplementation. Patients with IR, according to eGDR cut-off revealed significantly lower 25(OH)D serum level 15.7 (9.2-28.4) vs. 22.1 (13.0-38.4) ng/ml; p=0.04 as compared to patients without IR. R Spearman analysis found a positive relationship between VD and eGDR (Rs=0.27; p<0.01). Logistic regression analysis revealed significant relationship between the presence of IR and VD serum level/presence of 25(OH)D serum level below 10 ng/ml, both models adjusted to sex, age, BMI, LDL and triglycerides, accordingly (OR=0.95, CI: 0.90-0.99; p=0.04) and (OR=4.19, CI: 1.04-16.93; p=0.04).

CONCLUSION

The serum concentration of Vitamin D is negatively associated with insulin resistance in patients with T1DM and may have clinical implications.

Antioxidative potential of antidiabetic agents: A possible protective mechanism against vascular complications in diabetic patients

Many vascular complications are related to exposure of tissues to elevated levels of glucose, a condition that promotes oxidative stress. The primary goal of antidiabetic medication is for normalization of blood glucose. However, antidiabetic medications may have antioxidant effects that go beyond their hypoglycemic influences. Therefore, antidiabetic drugs may be doubly beneficial in preventing diabetic complications. Vascular dysfunction due to uncontrolled diabetes is a serious complication of the disease and one which has a severe impact on quality of life. Readjustment of the oxidative balance in subjects with diabetes, and the positive effects thereof is a topic of intense interest at present. In the current review, we highlight the antioxidant effects of antidiabetic medications which may prevent or delay the onset of vascular dysfunction.

Differential associations of lower cardiac vagal tone with insulin resistance and insulin secretion in recently diagnosed type 1 and type 2 diabetes

OBJECTIVE

It is unclear to which extent altered insulin sensitivity/secretion contribute to the development of diabetic cardiovascular autonomic neuropathy (CAN) characterized by diminished heart rate variability (HRV). We hypothesised that lower HRV is differentially associated with measures of insulin resistance and insulin secretion in recent-onset type 1 and type 2 diabetes.

MATERIALS/METHODS

This cross-sectional study included participants from the German Diabetes Study with type 1 (n=275) or type 2 diabetes (n=450) with known diabetes duration ≤1year and glucose-tolerant controls (n=81). Four time domain and frequency domain HRV measures each, reflecting vagal and/or sympathetic modulation were determined over 3h during a hyperinsulinaemic-euglycaemic clamp. Insulin sensitivity was calculated as the M-value, while insulin secretion was determined by glucagon-stimulated incremental C-peptide (ΔC-peptide).

RESULTS

After adjustment for sex, age, BMI, smoking, and HbA1c, both M-value and ΔC-peptide were lower in the diabetes groups compared to controls (P<0.05). In multiple linear regression analyses after Bonferroni correction, vagus-mediated HRV indices were positively associated with M-value in both diabetes types (P<0.05) and inversely associated with ΔC-peptide only in participants with type 1 diabetes (P<0.05). In type 2 diabetes, the low-frequency/high-frequency (LF/HF) power as an indicator of sympathovagal balance was weakly inversely associated with M-value.

CONCLUSIONS

Insulin resistance may contribute to the development of early cardiovagal suppression rather than sympathetic predominance in both diabetes types, while in type 1 diabetes a lower glucagon-stimulated insulin secretion is linked to a possibly compensatory higher parasympathetic tone. Whether interventions aimed at reducing insulin resistance could also reduce the risk of CAN remains to be established.

Gonadal Hormones and Retinal Disorders: A Review

AIM

Gonadal hormones are essential for reproductive function, but can act on neural and other organ systems, and are probably the cause of the large majority of known sex differences in function and disease. The aim of this review is to provide evidence for this hypothesis in relation to eye disorders and to retinopathies in particular.

METHODS

Epidemiological studies and research articles were reviewed.

RESULTS

Analysis of the biological basis for a relationship between eye diseases and hormones showed that estrogen, androgen, and progesterone receptors are present throughout the eye and that these steroids are locally produced in ocular tissues. Sex hormones can have a neuroprotective action on the retina and modulate ocular blood flow. There are differences between the male and the female retina; moreover, sex hormones can influence the development (or not) of certain disorders. For example, exposure to endogenous estrogens, depending on age at menarche and menopause and number of pregnancies, and exposure to exogenous estrogens, as in hormone replacement therapy and use of oral contraceptives, appear to protect against age-related macular degeneration (both drusenoid and neurovascular types), whereas exogenous testosterone therapy is a risk factor for central serous chorioretinopathy. Macular hole is more common among women than men, particularly in postmenopausal women probably owing to the sudden drop in estrogen production in later middle age. Progestin therapy appears to ameliorate the course of retinitis pigmentosa. Diabetic retinopathy, a complication of diabetes, may be more common among men than women.

CONCLUSION

We observed a correlation between many retinopathies and sex, probably as a result of the protective effect some gonadal hormones may exert against the development of certain disorders. This may have ramifications for the use of hormone therapy in the treatment of eye disease and of retinal disorders in particular.

Circulating matrix metalloproteinases are associated with arterial stiffness in patients with type 1 diabetes: pooled analysis of three cohort studies

Background

Altered regulation of extracellular matrix (ECM) composition by matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) may contribute to arterial stiffening. We investigated associations between circulating MMP-1, -2, -3, -9, -10 and TIMP-1, and carotid-femoral pulse wave velocity (cfPWV) and pulse pressure (PP), as markers of arterial stiffness in type 1 diabetic patients.

Methods

Individuals with type 1 diabetes from three different cohorts were included in this study: EURODIAB Prospective Complications study (n = 509), LEACE (n = 370) and PROFIL (n = 638). Linear regression analyses were used to investigate cross-sectional associations between circulating levels of MMP-1, -2, -3, -9, -10, and TIMP-1 and cfPWV (n = 614) as well as office PP (n = 1517). Data on 24-h brachial and 24-h central PP were available in 638 individuals from PROFIL. Analyses were adjusted for age, sex, duration of diabetes, HbA1c, mean arterial pressure (MAP), and eGFR, and additionally for other cardiovascular risk factors and presence of vascular complications.

Results

After adjustment for potential confounders and presence of vascular complications, circulating MMP-3 was associated with cfPWV [β per 1 SD higher lnMMP3 0.29 m/s (0.02; 0.55)]. In addition, brachial and central 24-h PP measurements in PROFIL were significantly associated with MMP-2 [(1.40 (0.47:2.33) and 1.43 (0.63:2.23)]. Pooled data analysis showed significant associations of circulating levels of MMP-1 and MMP-2 with office PP [β per 1 SD higher lnMMP-1 and lnMMP-2 = − 0.83 mmHg (95% CI − 1.50; − 0.16) and = 1.33 mmHg (0.55; 2.10), respectively].

Conclusions

MMPs-1, -2, and -3 are independently associated with markers of arterial stiffening in patients with type 1 diabetes and may become therapeutic targets.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-017-0620-9) contains supplementary material, which is available to authorized users.

Obesity, metabolic syndrome and diabetic retinopathy: Beyond hyperglycemia

Diabetic retinopathy (DR) is the most feared ocular manifestation of diabetes. DR is characterized by progressive retinal damage that may eventually result in blindness. Clinically, this blindness is caused by progressive damage to the retinal microvasculature, which leads to ischemia, retinal swelling, and neovascularization. Retinopathy is associated with both type 1 and type 2 diabetes, with DR being the leading cause of new onset blindness in United States adults. Despite this strong association with diabetes, it must be noted that the development of retinopathy lesions is multifactorial and may occur in individuals without an established history of diabetes. Metabolic syndrome is a multifactorial condition of central obesity, hypertriglyceridemia, dyslipidemia, hypertension, fasting hyperglycemia, and insulin resistance. Although several studies examined the individual components observed in the metabolic syndrome in relation to the development of DR, there is conflicting data as to the association of the metabolic syndrome with the development of retinopathy lesions in non-diabetic subjects. This review will summarize the current literature on the evidence of the metabolic syndrome on retinopathy in subjects with and without an established history of diabetes. This review will also discuss some of the mechanisms through which metabolic syndrome can contribute to the development of retinopathy.

Potential Association of Triglyceride Glucose Index with Cardiac Autonomic Neuropathy in Type 2 Diabetes Mellitus Patients

Cardiac autonomic neuropathy (CAN) is a common and most neglected complication of diabetes, estimated to be roughly 8% in recently diagnosed patients and greater than 50% in patients with chronic disease history. The insulin resistance (IR) itself is bidirectionally associated with increased risk of type 2 diabetes mellitus (T2DM) and CAN is a predisposing factor. The primary objective of the present study was aimed to find a correlation of triglyceride glucose index (TyG index) in CAN patients along with the prevalence of CAN in T2DM patients as a secondary objective. This prevalence study was conducted on 202 patients visiting the diabetic clinic of Hamdard Institute of Medical Sciences and Research, Jamia Hamdard (HIMSR) teaching hospital in New Delhi, India who fulfilled the inclusion criteria. The Ewings autonomic function test was used for diagnosis of CAN. TyG index was calculated for patients based on fasting levels of glucose and triglyceride. The CAN was diagnosed in 62 participants out of 202 T2DM patients (overall prevalence 30.7%). The mean ± standard deviation (SD) for TyG index was 10.3 ± 0.2 and 9.5 ± 0.2 in CAN positive, T2DM patients, respectively. The difference of TyG index, in CAN positive and T2DM patients, was highly significant (P < 0.001). Further correlation analysis was performed to find an association of TyG index, duration, and age with patient groups. TyG index showed a positive correlation with heart rate during deep breathing (HRD), heart rate variation during standing (HRS), blood pressure (BP) response to handgrip and BP response to standing. Our finding highlights the TyG index, low-cost IR index, might be useful as an alternative tool for the early screening of patients at a high risk of diabetic neuropathy.

Sex differences in micro- and macro-vascular complications of diabetes mellitus

Vascular complications are a leading cause of morbidity and mortality in both men and women with type 1 (T1DM) or type 2 (T2DM) diabetes mellitus, however the prevalence, progression and pathophysiology of both microvascular (nephropathy, neuropathy and retinopathy) and macrovascular [coronary heart disease (CHD), myocardial infarction, peripheral arterial disease (PAD) and stroke] disease are different in the two sexes. In general, men appear to be at a higher risk for diabetic microvascular complications, while the consequences of macrovascular complications may be greater in women. Interestingly, in the absence of diabetes, women have a far lower risk of either micro- or macro-vascular disease compared with men for much of their lifespan. Thus, the presence of diabetes confers greater risk for vascular complications in women compared with men and some of the potential reasons, including contribution of sex hormones and sex-specific risk factors are discussed in this review. There is a growing body of evidence that sex hormones play an important role in the regulation of cardiovascular function. While estrogens are generally considered to be cardioprotective and androgens detrimental to cardiovascular health, recent findings challenge these assumptions and demonstrate diversity and complexity of sex hormone action on target tissues, especially in the setting of diabetes. While some progress has been made toward understanding the underlying mechanisms of sex differences in the pathophysiology of diabetic vascular complications, many questions and controversies remain. Future research leading to understanding of these mechanisms may contribute to personalized- and sex-specific treatment for diabetic micro- and macro-vascular disease.

MicroRNA-126 and micro-/macrovascular complications of type 1 diabetes in the EURODIAB Prospective Complications Study

AIMS

Increasing evidence suggests a potential role of circulating miRNAs as clinical biomarkers, and loss of miRNA-126 has been proposed as a predictor of type 2 diabetes onset. However, a systematic analysis of circulating miRNAs in type 1 diabetic patients with micro-/macrovascular complications has not yet been performed.

METHODS

A cross-sectional nested case-control study from the EURODIAB Prospective Complications Study of 455 type 1 diabetic patients was performed. Case subjects (n = 312) were defined as those with one or more complications of diabetes; control subjects (n = 143) were those with no evidence of any complication. A differential miRNA expression profiling was performed in pooled serum samples from cases and controls. Furthermore, miR-126 levels were quantified by qPCR in all individual samples and associations with diabetic complications investigated.

RESULTS

Twenty-five miRNAs differed in pooled samples from cases and controls. miR-126 levels were significantly lower in case than in control subjects, even after adjustment for age and sex. In logistic regression analyses, miR-126 was negatively associated with all complications (OR = 0.85, 95 % CI 0.75-0.96) as well as with each micro-/macrovascular complication examined separately. This was likely dependent of diabetes as associations were no longer significant after adjustment for both hyperglycemia and diabetes duration. However, a significant 25 % risk reduction, independent of age, sex, A1C, and diabetes duration, was still observed for proliferative retinopathy (OR = 0.75, 95 % CI 0.59-0.95).

CONCLUSIONS

In this large cohort of type 1 diabetic subjects, we found that miR-126 levels are associated with vascular complications of diabetes, particularly with proliferative retinopathy.

Does Retinal Neurodegeneration Seen in Diabetic Patients Begin in the Insulin Resistance Stage?

OBJECTIVES

To investigate whether retinal neurodegeneration and impairment in contrast sensitivity (CS), which have been demonstrated to begin in diabetic patients before the presence of signs of diabetic retinal vasculopathy, also occur in the stage of insulin resistance.

MATERIALS AND METHODS

The average, minimum and sectoral (inferior, superior, inferonasal, superonasal, inferotemporal and superotemporal) thicknesses of the ganglion cell-inner plexiform layer (GCIPL) measured using optical coherence tomography were compared between an insulin-resistant group and control group in order to evaluate the presence of retinal neurodegeneration. The CS of the two groups was also compared according to the logarithmic values measured at spatial frequencies of 1.5, 3, 6, 12 and 18 cycles per degree in photopic light using functional acuity contrast test (FACT).

RESULTS

Twenty-five eyes of 25 patients with insulin resistance (insulin resistant group) and 25 eyes of 25 healthy subjects (control group) were included in this study. There were no statistically significant differences between the two groups in any of the spatial frequencies in the FACT. The mean average GCIPL thickness and mean GCIPL thickness in the inferotemporal sector were significantly less in the insulin-resistant group when compared with the control group (mean average GCIPL thicknesses in the insulin-resistant and control groups were 83.6±4.7 µm and 86.7±3.7 µm respectively, p=0.01; mean inferotemporal GCIPL thicknesses in the insulin-resistant and control groups were 83±6.0 µm and 86.7±4.6 µm respectively, p=0.02).

CONCLUSION

Although it may not lead to functional visual impairment such as CS loss, the retinal neurodegeneration seen in diabetic patients may begin in the insulin resistance stage.

Jiangzhi Capsule improves fructose-induced insulin resistance in rats: Association with repair of the impaired sarcolemmal glucose transporter-4 recycling

ETHNOPHARMACOLOGICAL RELEVANCE

Jiangzhi Capsule, originated from an experienced formula in traditional Chinese Medicine, has been listed and used for the management of metabolic abnormalities in Australia for a long time. To better understand Jiangzhi Capsule, this study investigated its effect on insulin resistance.

MATERIALS AND METHODS

Male rats were treated with liquid fructose in their drinking water over 14 weeks. Jiangzhi Capsule was co-administered (once daily, by oral gavage) during the last 7 weeks. Indexes of lipid and glucose homeostasis were determined enzymatically, by ELISA and/or histologically. Gene expression was analyzed by real-time PCR, Western blot and/or immunohistochemistry.

RESULTS

Treatment with Jiangzhi Capsule (100mg/kg) attenuated fructose overconsumption-induced increases in basal plasma insulin concentrations, the homeostasis model assessment of insulin resistance index and the adipose tissue insulin resistance index in rats. The increased plasma glucose concentrations during oral glucose tolerance test were also inhibited. Furthermore, Jiangzhi Capsule had a trend to attenuate the decreased ratios of glucose and non-esterified fatty acids to plasma insulin concentrations. Mechanistically, this insulin-sensitizing action was accompanied by normalization of the downregulated sarcolemmal glucose transporter (GLUT)-4 protein expression and the decreased phosphorylated Akt to total Akt protein ratio in gastrocnemius.

CONCLUSIONS

These results suggest that Jiangzhi Capsule ameliorates fructose-induced insulin resistance with a link to repair of the impaired sarcolemmal GLUT-4 recycling through modulation of the ratio of phosphorylated Akt to total Akt in gastrocnemius. Our findings provide an evidence-based and mechanistic understanding of Jiangzhi Capsule for the management of insulin resistance-associated disorders.

Prevalence and risk factors for diabetic retinopathy in a hospital-based population of Australian children and adolescents with type 1 diabetes

BACKGROUND

The aim of this study was to investigate the prevalence of, and traditional and emerging risk factors associated with, retinopathy in a hospital-based population of Australian children and adolescents with type 1 diabetes.

METHODS

This was a cross-sectional study of 483 children and adolescents with type 1 diabetes. Medical files were audited to collect all relevant clinical data. Diabetic retinopathy was assessed from colour retinal images by an ophthalmologist.

RESULTS

Diabetic retinopathy was observed in 11 (2.3%) participants. Logistic regression revealed that the principal components analysis derived risk profile of: higher serum creatinine, older age, higher systolic blood pressures, higher body mass index, abnormal estimated glomerular filtration rate (eGFR) (<59 mL/min), lower high density lipoproteins (HDL) cholesterol, higher serum sodium, longer duration of diabetes and narrower retinal arteriolar calibre was associated with diabetic retinopathy (ExpB=2.60, 95% CI 1.36/4.96, p=0.004).

CONCLUSIONS

These results support the concept that the pathogenesis of diabetic retinopathy is likely due to the combined influence of various risk factors, many already identified.

[Vascular endothelial growth factors (VEGF): role in pathological processes]

Russian and foreign literature sources on vascular endothelial growth factors (VEGF) from different parts of the human body, their prevalence and involvement in pathological processes were analyzed. A conclusion has been drawn that further research on different types of VEGF is needed.

Epidemiology of diabetic retinopathy, diabetic macular edema and related vision loss

Diabetic retinopathy (DR) is a leading cause of vision-loss globally. Of an estimated 285 million people with diabetes mellitus worldwide, approximately one third have signs of DR and of these, a further one third of DR is vision-threatening DR, including diabetic macular edema (DME). The identification of established modifiable risk factors for DR such as hyperglycemia and hypertension has provided the basis for risk factor control in preventing onset and progression of DR. Additional research investigating novel risk factors has improved our understanding of multiple biological pathways involved in the pathogenesis of DR and DME, especially those involved in inflammation and oxidative stress. Variations in DR prevalence between populations have also sparked interest in genetic studies to identify loci associated with disease susceptibility. In this review, major trends in the prevalence, incidence, progression and regression of DR and DME are explored, and gaps in literature identified. Established and novel risk factors are also extensively reviewed with a focus on landmark studies and updates from the recent literature.

Epidemiology of diabetic retinopathy, diabetic macular edema and related vision loss

Diabetic retinopathy (DR) is a leading cause of vision-loss globally. Of an estimated 285 million people with diabetes mellitus worldwide, approximately one third have signs of DR and of these, a further one third of DR is vision-threatening DR, including diabetic macular edema (DME). The identification of established modifiable risk factors for DR such as hyperglycemia and hypertension has provided the basis for risk factor control in preventing onset and progression of DR. Additional research investigating novel risk factors has improved our understanding of multiple biological pathways involved in the pathogenesis of DR and DME, especially those involved in inflammation and oxidative stress. Variations in DR prevalence between populations have also sparked interest in genetic studies to identify loci associated with disease susceptibility. In this review, major trends in the prevalence, incidence, progression and regression of DR and DME are explored, and gaps in literature identified. Established and novel risk factors are also extensively reviewed with a focus on landmark studies and updates from the recent literature.

Age-related eye disease and gender

Worldwide, the prevalence of moderate to severe visual impairment and blindness is 285 millions, with 65% of visually impaired and 82% of all blind people being 50 years and older. Meta-analyses have shown that two out of three blind people are women, a gender discrepancy that holds true for both developed and developing countries. Cataract accounts for more than half of all blindness globally and gender inequity in access to cataract surgery is the major cause of the higher prevalence of blindness in women. In addition to gender differences in cataract surgical coverage, population-based studies on the prevalence of lens opacities indicate that women have a higher risk of developing cataract. Laboratory as well as epidemiologic studies suggest that estrogen may confer antioxidative protection against cataractogenesis, but the withdrawal effect of estrogen in menopause leads to increased risk of cataract in women. For the other major age-related eye diseases; glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy, data are inconclusive. Due to anatomic factors, angle closure glaucoma is more common in women, whereas the dominating glaucoma type; primary open-angle glaucoma (POAG), is more prevalent in men. Diabetic retinopathy also has a male predominance and vascular/circulatory factors have been implied both in diabetic retinopathy and in POAG. For AMD, data on gender differences are conflicting although some studies indicate increased prevalence of drusen and neovascular AMD in women. To conclude, both biologic and socioeconomic factors must be considered when investigating causes of gender differences in the prevalence of age-related eye disease.

Epidemiology of diabetic retinopathy, diabetic macular edema and related vision loss

Diabetic retinopathy (DR) is a leading cause of vision-loss globally. Of an estimated 285 million people with diabetes mellitus worldwide, approximately one third have signs of DR and of these, a further one third of DR is vision-threatening DR, including diabetic macular edema (DME). The identification of established modifiable risk factors for DR such as hyperglycemia and hypertension has provided the basis for risk factor control in preventing onset and progression of DR. Additional research investigating novel risk factors has improved our understanding of multiple biological pathways involved in the pathogenesis of DR and DME, especially those involved in inflammation and oxidative stress. Variations in DR prevalence between populations have also sparked interest in genetic studies to identify loci associated with disease susceptibility. In this review, major trends in the prevalence, incidence, progression and regression of DR and DME are explored, and gaps in literature identified. Established and novel risk factors are also extensively reviewed with a focus on landmark studies and updates from the recent literature.

New Therapeutic Approaches in Diabetic Retinopathy

Diabetic retinopathy is a common microvascular complication of diabetes mellitus. It affects a substantial proportion of US adults over age 40. The condition is a leading cause of visual loss. Much attention has been given to expanding the role of current treatments along with investigating various novel therapies and drug delivery methods. In the treatment of diabetic macular edema (DME), intravitreal pharmacotherapies, especially anti-vascular endothelial growth factor (anti-VEGF) agents, have gained popularity. Currently, anti-VEGF agents are often used as first-line agents in center-involved DME, with recent data suggesting that among these agents, aflibercept leads to better visual outcomes in patients with worse baseline visual acuities. While photocoagulation remains the standard treatment for proliferative diabetic retinopathy (PDR), recent FDA approvals of ranibizumab and aflibercept in the management of diabetic retinopathy associated with DME may suggest a potential for pharmacologic treatments of PDR as well. Novel therapies, including small interfering RNAs, chemokines, kallikrein-kinin inhibitors, and various anti-angiogenic agents, are currently being evaluated for the management of diabetic retinopathy and DME. In addition to these strategies, novel drug delivery methods such as sustained-release implants and refillable reservoir implants are either under active evaluation or have recently gained FDA approval. This review provides an update on the novel developments in the treatment of diabetic retinopathy.