Clinical factors associated with resistance to microvascular complications in diabetic patients of extreme disease duration: the 50-year medalist study

Circulating microRNAs demonstrate limited diagnostic potential for diabetic retinopathy in the population of Kazakhstan

Background

Diabetic retinopathy (DR) is the most common complication of diabetes, leading to blindness. The asymptomatic onset and the existing difficulties in diagnosing warrant the search for biomarkers that can facilitate the early diagnosis of DR. The aim of this study was to evaluate the potential of plasma microRNAs (miRNAs), which have previously been shown to be involved in the pathogenesis of DR and differentially expressed in plasma/serum of patients, as biomarkers for DR in the Kazakhstani population.

Materials and Methods

Using quantitative RT-PCR, we compared the levels of ten candidate miRNAs in plasma among three groups: type 2 diabetes mellitus (T2DM) patients with DR (DR patients, N = 100), T2DM patients without DR (noDR patients, N = 98), and healthy controls (N = 30).

Results

Level of miR-423-3p was significantly reduced in DR patients compared to noDR patients (pFDR = 5.4 × 10-3). Levels of miR-423-3p and miR-221-3p were significantly reduced in DR patients compared to controls (pFDR = 5.4 × 10-3 and 0.024, respectively ), level of miR-23a-3p was significantly reduced in noDR patients compared to controls (pFDR = 0.047), levels of miR-221-3p and miR-23a-3p were significantly reduced in T2DM patients (combined group) compared to controls (pFDR = 0.047, and 0.049, respectively). Also, there were several significant differences between groups formed based on clinical-pathological characteristics, but none of these results remained significant after adjustment for multiple comparisons. Correlation analysis revealed weak associations between the levels of miR-423 and miR-221-3p and DR staging (pFDR = 1.3 × 10-3 and 0.026, respectively), and fair associations between the levels of miR-29b-3p and miR-328-3p and diabetes duration in noDR patients (pFDR = 8.8 × 10-3 and 0.016, respectively). According to receiver operating characteristic (ROC) analysis, only miR-23a-3p can be considered a potential biomarker with moderate informativeness for diagnosing proliferative DR (PDR); however, a larger sample size is needed to verify this finding. Furthermore, the small magnitude of observed changes in miRNA levels between groups significantly complicates classification.

Conclusions

Due to the low specificity and small magnitude of deviations from the norm, the studied miRNAs have low potential in the diagnosis of DR.

Association between retinal vessels caliber and systemic health: A comprehensive review

The unique nature of the retinal microvasculature that permits non-invasive visualization has garnered interest as a potential method for detecting microvascular alterations indicative of systemic diseases. This concept, supported by advancements in imaging technologies, has been increasingly validated by studies linking retinal microvasculature with systemic conditions such as diabetes, hypertension, and cerebrovascular disease. Structural changes in the retinal microvasculature are associated with cardiovascular risk factors, metabolic diseases, and are significant predictors of systemic hypertensive damage and mortality. Given that most systemic diseases present life-long burdens and complications if undetected or untreated, the development of diagnostic tools like retinal vascular imaging becomes important for early detection, monitoring of disease progression, and facilitating timely interventions. Technological advancements have enabled objective and accurate quantification of retinal microvascular characteristics. We consolidate current literature on retinal vascular changes across various systemic health conditions, including metabolic diseases, cerebrovascular diseases, pregnancy complications, systemic inflammatory conditions, leukemia, human immunodeficiency virus infection, and COVID-19. We also emphasizes the need for dynamic parameters, an understanding of 3-dimensional vascular architecture, and larger-scale longitudinal studies to elucidate the temporal relationship between retinal vascular changes and systemic diseases, helping shape future diagnostic and monitoring approaches.

Identification of Metabolic Patterns in Korean Patients With Type 2 Diabetes and Their Association With Diabetes-Related Complications

ARTICLE HIGHLIGHTS

Identifying patterns of metabolic heterogeneity in type 2 diabetes (T2D) can help in the development of optimal treatment strategies. We aimed to identify metabolic patterns in patients with T2D in the Republic of Korea and analyze the risk of developing diabetes-related complications according to patterns. We identified three distinct metabolic patterns and observed that each pattern was associated with a heightened risk of developing various cardiovascular diseases. These findings highlight the necessity of devising treatment strategies based on these patterns to prevent diabetes-related complications.

Characterization of cognitive decline in long-duration type 1 diabetes by cognitive, neuroimaging, and pathological examinations

BACKGROUNDWe aimed to characterize factors associated with the under-studied complication of cognitive decline in aging people with long-duration type 1 diabetes (T1D).METHODSJoslin "Medalists" (n = 222; T1D ≥ 50 years) underwent cognitive testing. Medalists (n = 52) and age-matched nondiabetic controls (n = 20) underwent neuro- and retinal imaging. Brain pathology (n = 26) was examined. Relationships among clinical, cognitive, and neuroimaging parameters were evaluated.RESULTSCompared with controls, Medalists had worse psychomotor function and recall, which associated with female sex, lower visual acuity, reduced physical activity, longer diabetes duration, and higher inflammatory cytokines. On neuroimaging, compared with controls, Medalists had significantly lower total and regional brain volumes, equivalent to 9 years of accelerated aging, but small vessel disease markers did not differ. Reduced brain volumes associated with female sex, reduced psychomotor function, worse visual acuity, longer diabetes duration, and higher inflammation, but not with glycemic control. Worse cognitive function, lower brain volumes, and diabetic retinopathy correlated with thinning of the outer retinal nuclear layer. Worse baseline visual acuity associated with declining psychomotor function in longitudinal analysis. Brain volume mediated the association between visual acuity and psychomotor function by 57%. Brain pathologies showed decreased volumes, but predominantly mild vascular or Alzheimer's-related pathology.CONCLUSION To our knowledge, this is the first comprehensive study of cognitive function, neuroimaging, and pathology in aging T1D individuals demonstrated that cognitive decline was related to parenchymal rather than neurovascular abnormalities, unlike type 2 diabetes, suggestive of accelerated aging in T1D. Improving visual acuity could perhaps be an important preventive measure against cognitive decline in people with T1D.FUNDINGThe Beatson Foundation, NIH/NIDDK grants 3P30DK036836-34S1 and P30DK036836-37, and Mary Iacocca fellowships.

Long-duration type 1 diabetes is associated with deficient cortical bone mechanical behavior and altered matrix composition in human femoral bone

Type 1 diabetes (T1D) is associated with an increased risk of hip fracture beyond what can be explained by reduced bone mineral density, possibly due to changes in bone material from accumulation of advanced glycation end-products (AGEs) and altered matrix composition, though data from human cortical bone in T1D are limited. The objective of this study was to evaluate cortical bone material behavior in T1D by examining specimens from cadaveric femora from older adults with long-duration T1D (≥50 yr; n = 20) and age- and sex-matched nondiabetic controls (n = 14). Cortical bone was assessed by mechanical testing (4-point bending, cyclic reference point indentation, impact microindentation), AGE quantification [total fluorescent AGEs, pentosidine, carboxymethyl lysine (CML)], and matrix composition via Raman spectroscopy. Cortical bone from older adults with T1D had diminished postyield toughness to fracture (-30%, p = .036), elevated levels of AGEs (pentosidine, +17%, p = .039), lower mineral crystallinity (-1.4%, p = .010), greater proline hydroxylation (+1.9%, p = .009), and reduced glycosaminoglycan (GAG) content (-1.3%, p < .03) compared to nondiabetics. In multiple regression models to predict cortical bone toughness, cortical tissue mineral density, CML, and Raman spectroscopic measures of enzymatic collagen crosslinks and GAG content remained highly significant predictors of toughness, while diabetic status was no longer significant (adjusted R2 > 0.60, p < .001). Thus, the impairment of cortical bone to absorb energy following long-duration T1D is well explained by AGE accumulation and modifications to the bone matrix. These results provide novel insight into the pathogenesis of skeletal fragility in individuals with T1D.

Transient but not chronic hyperglycemia accelerates ocular glymphatic transport

Glymphatic transport is vital for the physiological homeostasis of the retina and optic nerve. Pathological alterations of ocular glymphatic fluid transport and enlarged perivascular spaces have been described in glaucomatous mice. It remains to be established how diabetic retinopathy, which impairs vision in about 50% of diabetes patients, impacts ocular glymphatic fluid transport. Here, we examined ocular glymphatic transport in chronic hyperglycemic diabetic mice as well as in healthy mice experiencing a daily transient increase in blood glucose. Mice suffering from severe diabetes for two and four months, induced by streptozotocin, exhibited no alterations in ocular glymphatic fluid transport in the optic nerve compared to age-matched, non-diabetic controls. In contrast, transient increases in blood glucose induced by repeated daily glucose injections in healthy, awake, non-diabetic mice accelerated antero- and retrograde ocular glymphatic transport. Structural analysis showed enlarged perivascular spaces in the optic nerves of glucose-treated mice, which were absent in diabetic mice. Thus, transient repeated hyperglycemic events, but not constant hyperglycemia, ultimately enlarge perivascular spaces in the murine optic nerve. These findings indicate that fluid transport in the mouse eye is vulnerable to fluctuating glycemic levels rather than constant hyperglycemia, suggesting that poor glycemic control drives glymphatic malfunction and perivascular enlargement in the optic nerve.

Protective Factors and the Pathogenesis of Complications in Diabetes

Chronic complications of diabetes are due to myriad disorders of numerous metabolic pathways that are responsible for most of the morbidity and mortality associated with the disease. Traditionally, diabetes complications are divided into those of microvascular and macrovascular origin. We suggest revising this antiquated classification into diabetes complications of vascular, parenchymal, and hybrid (both vascular and parenchymal) tissue origin, since the profile of diabetes complications ranges from those involving only vascular tissues to those involving mostly parenchymal organs. A major paradigm shift has occurred in recent years regarding the pathogenesis of diabetes complications, in which the focus has shifted from studies on risks to those on the interplay between risk and protective factors. While risk factors are clearly important for the development of chronic complications in diabetes, recent studies have established that protective factors are equally significant in modulating the development and severity of diabetes complications. These protective responses may help explain the differential severity of complications, and even the lack of pathologies, in some tissues. Nevertheless, despite the growing number of studies on this field, comprehensive reviews on protective factors and their mechanisms of action are not available. This review thus focused on the clinical, biochemical, and molecular mechanisms that support the idea of endogenous protective factors, and their roles in the initiation and progression of chronic complications in diabetes. In addition, this review also aimed to identify the main needs of this field for future studies.

Fasted C-Peptide Distribution and Associated Clinical Factors in Adults With Longstanding Type 1 Diabetes: Analysis of the Canadian Study of Longevity in Type 1 Diabetes

OBJECTIVE

Although insulin production is reportedly retained in many people with longstanding type 1 diabetes (T1D), the magnitude and relevance of connecting peptide (C-peptide) production are uncertain. In this study, we aimed to define fasted C-peptide distributions and associated clinical factors.

METHODS

In a cross-sectional analysis of the Canadian Study of Longevity, fasted serum and urinary C-peptide was measured in 74 patients with longstanding T1D (duration ≥50 years) and 75 age- and sex-matched controls. Extensive phenotyping for complications was performed and patient-reported variables were included. C-peptide distributions were analyzed, and multivariable logistic regression was used to assess the variable association in participants with T1D.

RESULTS

The 74 participants with T1D had a mean age of 66±8 years, a disease duration of 54 (interquartile range 52 to 58) years, and a glycated hemoglobin (A1C) of 7.4%±0.8% (56.8±9.15 mmol/mol). The 75 controls had a mean age of 65±8 years and an A1C of 5.7%±0.4% (38.4±4.05 mmol/mol). Participants with T1D had lower fasted serum C-peptide than controls (0.013±0.022 vs 1.595±1.099 nmol/L, p<0.001). Of the participants with T1D, C-peptide was detectable in 30 of 73 (41%) serum samples, 32 of 74 (43%) urine samples, and 48 of 74 (65%) for either serum or urine. The variables independently associated with detectable serum or urinary C-peptide were lower total daily insulin requirement (odds ratio 2.351 [for 1 lower unit/kg], p=0.013) and lower hypoglycemia worry score (odds ratio 1.059 [for 1 point lower on the worry subscore of the Hypoglycemia Fear Survey], p=0.030).

CONCLUSIONS

Although detectable C-peptide in longstanding diabetes was common, the magnitude of concentration was extremely low when compared with age- and sex-matched controls. Despite minimal detectability, its presence is validated by lower insulin requirements and strongly associated with lower hypoglycemia worry.

A Review on Diabetic Retinopathy

Diabetic retinopathy is a well-recognised microvascular complication of diabetes and is among the leading cause of blindness all over the world. Over the last decade, there have been advances in the diagnosis of diabetic retinopathy and diabetic macular edema. At the same time, newer therapies for the management of diabetic retinopathy have evolved. As a result of these advances, a decline in severe vision loss due to diabetes has been witnessed in some developing countries. However, there is a steady increase in the number of people affected with diabetes, and is expected to rise further in the coming years. Therefore, it is prudent to identify diabetic retinopathy, and timely intervention is needed to decrease the burden of severe vision loss. An effort has been made to review all the existing knowledge regarding diabetic retinopathy in this article and summarize the present treatment options for diabetic retinopathy.

New Insights on Dietary Polyphenols for the Management of Oxidative Stress and Neuroinflammation in Diabetic Retinopathy

Diabetic retinopathy (DR) is a neurodegenerative and vascular pathology that is considered one of the leading causes of blindness worldwide, resulting from complications of advanced diabetes mellitus (DM). Current therapies consist of protocols aiming to alleviate the existing clinical signs associated with microvascular alterations limited to the advanced disease stages. In response to the low resolution and limitations of the DR treatment, there is an urgent need to develop more effective alternative therapies to optimize glycemic, vascular, and neuronal parameters, including the reduction in the cellular damage promoted by inflammation and oxidative stress. Recent evidence has shown that dietary polyphenols reduce oxidative and inflammatory parameters of various diseases by modulating multiple cell signaling pathways and gene expression, contributing to the improvement of several chronic diseases, including metabolic and neurodegenerative diseases. However, despite the growing evidence for the bioactivities of phenolic compounds, there is still a lack of data, especially from human studies, on the therapeutic potential of these substances. This review aims to comprehensively describe and clarify the effects of dietary phenolic compounds on the pathophysiological mechanisms involved in DR, especially those of oxidative and inflammatory nature, through evidence from experimental studies. Finally, the review highlights the potential of dietary phenolic compounds as a prophylactic and therapeutic strategy and the need for further clinical studies approaching the efficacy of these substances in DR management.

Residual β-cell function in Brazilian Type 1 diabetes after 3 years of diagnosis: prevalence and association with low presence of nephropathy

BACKGROUND

Persistence of β cell-function in Type 1 diabetes (T1D) is associated with glycaemia stability and lower prevalence of microvascular complications. We aimed to assess the prevalence of residual C- peptide secretion in long-term Brazilian childhood onset T1D receiving usual diabetes care and its association to clinical, metabolic variables and microvascular complications.

METHODS

A cross-sectional observational study with 138 T1D adults with ≥ 3 years from the diagnosis by routine diabetes care. Clinical, metabolic variables and microvascular complications were compared between positive ultra-sensitive fasting serum C-peptide (FCP +) and negative (FCP-) participants.

RESULTS

T1D studied had ≥ 3 yrs. of diagnosis and 60% had FCP > 1.15 pmol/L. FCP + T1D were older at diagnosis (10 vs 8 y.o; p = 0.03) and had less duration of diabetes (11 vs 15 y.o; p = 0.002). There was no association between the FCP + and other clinical and metabolic variable but there was inversely association with microalbuminuria (28.6% vs 13.4%, p = 0.03), regardless of HbA_1c. FCP > 47 pmol/L were associated with nephropathy protection but were not related to others microvascular complications.

CONCLUSION

Residual insulin secretion is present in 60% of T1D with ≥ 3 years of diagnosis in routine diabetes care. FCP + was positively associated with age of diagnosis and negatively with duration of disease and microalbuminuria, regardless of HbA_1c.

Coronary Microvascular Dysfunction in Diabetes Mellitus: Pathogenetic Mechanisms and Potential Therapeutic Options

Diabetic patients are frequently affected by coronary microvascular dysfunction (CMD), a condition consisting of a combination of altered vasomotion and long-term structural change to coronary arterioles leading to impaired regulation of blood flow in response to changing cardiomyocyte oxygen requirements. The pathogenesis of this microvascular complication is complex and not completely known, involving several alterations among which hyperglycemia and insulin resistance play particularly central roles leading to oxidative stress, inflammatory activation and altered barrier function of endothelium. CMD significantly contributes to cardiac events such as angina or infarction without obstructive coronary artery disease, as well as heart failure, especially the phenotype associated with preserved ejection fraction, which greatly impact cardiovascular (CV) prognosis. To date, no treatments specifically target this vascular damage, but recent experimental studies and some clinical investigations have produced data in favor of potential beneficial effects on coronary micro vessels caused by two classes of glucose-lowering drugs: glucagon-like peptide 1 (GLP-1)-based therapy and inhibitors of sodium-glucose cotransporter-2 (SGLT2). The purpose of this review is to describe pathophysiological mechanisms, clinical manifestations of CMD with particular reference to diabetes, and to summarize the protective effects of antidiabetic drugs on the myocardial microvascular compartment.

Elevated Retinol Binding Protein 3 Concentrations Are Associated With Decreased Vitreous Inflammatory Cytokines, VEGF, and Progression of Diabetic Retinopathy

OBJECTIVE

To correlate inflammatory cytokines and vascular endothelial growth factor (VEGF) in vitreous and plasma with vitreous retinol binding protein 3 (RBP3), diabetic retinopathy (DR) severity, and DR worsening in a population with type 1 and type 2 diabetes.

RESEARCH DESIGN AND METHODS

RBP3, VEGF, and inflammatory cytokines were measured in plasma and vitreous samples (n = 205) from subjects of the Joslin Medalist Study and Beetham Eye Institute.

RESULTS

Higher vitreous RBP3 concentrations were associated with less severe DR (P < 0.0001) and a reduced risk of developing proliferative DR (PDR) (P < 0.0001). Higher RBP3 correlated with increased photoreceptor segment thickness and lower vitreous interleukin-12 (IL-12), tumor necrosis factor-α (TNF-α), and TNF-β (P < 0.05). PDR was associated with lower vitreous interferon-γ and IL-10 and higher VEGF, IL-6, and IL-15 (P < 0.05), but was not associated with their plasma concentrations.

CONCLUSIONS

Higher vitreous RBP3 concentrations are associated with less severe DR and slower rates of progression to PDR, supporting its potential as a biomarker and therapeutic agent for preventing DR worsening, possibly by lowering retinal VEGF and inflammatory cytokines.

Methylglyoxal and glyoxalase 1-a metabolic stress pathway-linking hyperglycemia to the unfolded protein response and vascular complications of diabetes

The study of the glyoxalase system by Thornalley and co-workers in clinical diabetes mellitus and correlation with diabetic complications revealed increased exposure of patients with diabetes to the reactive, dicarbonyl metabolite methylglyoxal (MG). Twenty-eight years later, extended and built on by Thornalley and co-workers and others, the glyoxalase system is an important pathway contributing to the development of insulin resistance and vascular complications of diabetes. Other related advances have been: characterization of a new kind of metabolic stress—‘dicarbonyl stress’; identification of the major physiological advanced glycation endproduct (AGE), MG-H1; physiological substrates of the unfolded protein response (UPR); new therapeutic agents—‘glyoxalase 1 (Glo1) inducers’; and a refined mechanism underlying the link of dysglycemia to the development of insulin resistance and vascular complications of diabetes.

Relationship between soluble protein ST2 (sST2) levels and microvascular complications in a cohort of patients with type 1 diabetes

AIM

To determine the association and the prognostic value of soluble ST2 (sST2) levels in the development of diabetic retinopathy (DR), diabetic macular oedema (DMO) or diabetic nephropathy (DN), in a cohort of patients with type 1 diabetes (T1D).

METHODS

A total of 269 individuals with T1D (154 males and 115 females) were recruited. The overall mean age was 43.2±14.9 years, and the diabetes duration was 17.1±12.1 years. Levels of sST2 in serum were evaluated, and the presence as well as the degree of DR, DMO and DN was recorded. Additionally, other clinical and analytical parameters including demographic variables were recovered from patients' electronic health record. Ten years later, the presence and stage of DR, DMO and DN were again recorded under the same criteria. The association between previously mentioned parameters with DR and DN was analysed by univariate and multivariate logistic regression. The variables in the final multivariate models were adjusted from complete models via backward elimination and maintained only when significant.

RESULTS

An increase of 10ng/ml in the levels of sST2 was associated with a 1.50 (1.02-2.19) and 1.48 (1.05-2.08) prevalence odds ratio (OR) in DMO and DR, respectively. There was no association between sST2 levels and DN. Meanwhile, sST2 levels did not display a prognostic effect in any of the microangiopathic diabetic complications studied.

CONCLUSIONS

Levels of sST2 are associated with the presence of DR and DMO, they do not seem to be predictive for the development or deterioration of DR, DMO or DN.

Integration of Metabolomics and Proteomics in Exploring the Endothelial Dysfunction Mechanism Induced by Serum Exosomes From Diabetic Retinopathy and Diabetic Nephropathy Patients

Background

The prevalence of diabetic microvascular diseases has increased significantly worldwide, the most common of which are diabetic nephropathy (DN) and diabetic retinopathy (DR). Microvascular endothelial cells are thought to be major targets of hyperglycemic damage, while the underlying mechanism of diffuse endothelial dysfunction in multiple organs needs to be further investigated.

Aim

The aim of this study is to explore the endothelial dysfunction mechanisms of serum exosomes (SExos) extracted from DR and DN (DRDN) patients.

Methods

In this study, human glomerular endothelial cells (HGECs) were used as the cell model. Metabolomics ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and proteomics tandem mass tag (TMT)-based liquid chromatography-tandem mass spectrometry (LC-MS/MS) together with bioinformatics, the correlation analysis, and the joint pathway analysis were employed to discover the underlying mechanisms of endothelial dysfunction caused by patient's SExos.

Results

It can be assumed that serum exosomes extracted by DRDN patients might cause endothelial dysfunction mainly by upregulating alpha subunit of the coagulation factor fibrinogen (FIBA) and downregulating 1-methylhistidine (1-MH). Bioinformatics analysis pointed to an important role in reducing excess cysteine and methionine metabolism.

Conclusion

FIBA overexpression and 1-MH loss may be linked to the pathogenicity of diabetic endothelial dysfunction in DR/DN, implying that a cohort study is needed to further investigate the role of FIBA and 1-MH in the development of DN and DR, as well as the related pathways between the two proteins.

"Clinical status and mortality in older adults with type 1 diabetes: Results from a public health system"

AIM

To evaluate clinical status and mortality in older adults with long-standing type 1 diabetes mellitus (T1D).

METHODS

Cross-sectional analysis of all patients with T1D for 50 years or more from a cohort followed since 2010 at Castilla-La Mancha Public Health Service (Spain). Primary outcome was HbA1c change during the follow-up (2010-2020 period). Secondary outcomes included evaluation of insulin and continuous glucose monitoring (CGM) use, cardiovascular risk factors (CVRF), diabetes chronic complications and mortality.

RESULTS

A total of fifty-five T1D patients were analysed. Mean age was 69.5 ± 8.3 yrs. and T1D duration of 54.7 ± 4.7 yrs. We detected a HbA1c reduction of -0.5% (-6 mmol/mol) [95% CI -0.1, -0.9 (-2, -10); P = 0.016]. CGM was used by 26% of the patients. More patients suffered from hypertension and obesity in 2020 (66% vs. 78%, P = 0.016; and 26% vs. 31%, P = 0.016; respectively). An increase of diabetic polyneuropathy was detected (45% vs. 67%, P = 0.008). Rate of mortality was higher among patients with long-standing T1D (26% vs. 3.5%, P < 0.001), due to cardiovascular disease (57%).

CONCLUSIONS

Older adults with long-standing T1D patients improved glycemic control although a worsening of CVRF and higher mortality rateweredetected.

Prolactin and vasoinhibin are endogenous players in diabetic retinopathy revisited

Diabetic retinopathy (DR) and diabetic macular edema (DME) are major causes for visual loss in adults. Nearly half of the world's population with diabetes has some degree of DR, and DME is a major cause of visual impairment in these patients. Severe vision loss occurs because of tractional retinal detachment due to retinal neovascularization, but the most common cause of moderate vision loss occurs in DME where excessive vascular permeability leads to the exudation and accumulation of extracellular fluid and proteins in the macula. Metabolic control stands as an effective mean for controlling retinal vascular alterations in some but not all patients with diabetes, and the search of other modifiable factors affecting the risk for diabetic microvascular complications is warranted. Prolactin (PRL) and its proteolytic fragment, vasoinhibin, have emerged as endogenous regulators of retinal blood vessels. PRL acquires antiangiogenic and anti-vasopermeability properties after undergoing proteolytic cleavage to vasoinhibin, which helps restrict the vascularization of ocular organs and, upon disruption, promotes retinal vascular alterations characteristic of DR and DME. Evidence is linking PRL (and other pituitary hormones) and vasoinhibin to DR and recent preclinical and clinical evidence supports their translation into novel therapeutic approaches.

Using Machine Learning Techniques to Develop Risk Prediction Models for the Risk of Incident Diabetic Retinopathy Among Patients With Type 2 Diabetes Mellitus: A Cohort Study

OBJECTIVE

To construct and validate prediction models for the risk of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus.

METHODS

Patients with type 2 diabetes mellitus hospitalized over the period between January 2010 and September 2018 were retrospectively collected. Eighteen baseline demographic and clinical characteristics were used as predictors to train five machine-learning models. The model that showed favorable predictive efficacy was evaluated at annual follow-ups. Multi-point data of the patients in the test set were utilized to further evaluate the model's performance. We also assessed the relative prognostic importance of the selected risk factors for DR outcomes.

RESULTS

Of 7943 collected patients, 1692 (21.30%) developed DR during follow-up. Among the five models, the XGBoost model achieved the highest predictive performance with an AUC, accuracy, sensitivity, and specificity of 0.803, 88.9%, 74.0%, and 81.1%, respectively. The XGBoost model's AUCs in the different follow-up periods were 0.834 to 0.966. In addition to the classical risk factors of DR, serum uric acid (SUA), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), estimated glomerular filtration rate (eGFR), and triglyceride (TG) were also identified to be important and strong predictors for the disease. Compared with the clinical diagnosis method of DR, the XGBoost model achieved an average of 2.895 years prior to the first diagnosis.

CONCLUSION

The proposed model achieved high performance in predicting the risk of DR among patients with type 2 diabetes mellitus at each time point. This study established the potential of the XGBoost model to facilitate clinicians in identifying high-risk patients and making type 2 diabetes management-related decisions.

Correlation between Diabetic Retinopathy and Diabetic Peripheral Neuropathy in Patients with Type II Diabetes Mellitus

Background and Objectives:

The two most common complications of diabetes mellitus are retinopathy and neuropathy which are dealt by two different medical departments. Early detection and management are therefore necessary to prevent progression of these two diseases and will give a knowledgeable idea regarding the both. Thus, this study was done to know the association of diabetic peripheral neuropathy and diabetic retinopathy.

Methods:

This was a cross sectional study comprised of 200 cases of type 2 diabetes mellitus selected from the ophthalmology department and referred cases from other departments. A thorough history and examination was done in both departments, that is, complete ophthalmic and neurological examination respectively. Relevant investigations, if needed, were done and diabetic retinopathy was classified according to ETDRS classification.

Results:

Of the 200 patients having type 2 diabetes for more than 5 years, 28% of cases had diabetic retinopathy and 59% of cases had peripheral neuropathy. Peripheral neuropathy was twice more common than retinopathy. 33.1% had retinopathy and 65.46% had peripheral neuropathy among the uncontrolled diabetics. The prevalence of retinopathy increased 1.3 times in patients with neuropathy (16%) than in patients without peripheral neuropathy (12%).

Conclusion:

As there was higher incidence of peripheral neuropathy, it is important as ophthalmologists to look for peripheral neuropathy in diabetics which will help in reducing diabetes-related morbidities.

Research Progress of circRNAs in Inflammatory Mechanisms of Diabetic Retinopathy: An Emerging Star with Potential Therapeutic Targets

PURPOSE

 We summarized the existing studies to elaborate the biogenesis and function of circRNAs, the effect of aberrant circRNAs expression in the mechanism of inflammation and diabetic retinopathy (DR) respectively and further explored the vital roles of circRNAs in inflammation involved in DR. Methods: We conducted a systematical literature search of abundant electronic databases (PubMed, GeneMedical and MEDLINE) up to August 2021. Results: In this review, we exhibited the biogenesis and function of circRNAs and highlighted the components of inflammatory mediators implicated in DR. Numerous circRNAs, such as circHIPK3, circZNF609, circRNA_0084043, circ_0002570, circ_0041795, circEhmt1 and circ-ITCH were discovered to play vital roles in inflammation involved in DR, which provided new ideas for diagnosis and treatment of DR. Moreover, we proposed not only the epigenetic functions of circRNAs but also novel forms of the inflammatory response, including pyroptosis, to inspire further exploration and creative research in this field. Conclusion: CircRNAs were implicated in the progression and development of inflammation in DR via aberrant expression and modulation of gene expression, serving as an emerging star with potential therapeutic targets.

Hypoxia-inducible factor-prolyl hydroxylase inhibitors for renal anemia in chronic kidney disease: Advantages and disadvantages

Anemia is a common feature and complication of chronic kidney disease (CKD). Erythropoiesis-stimulating agents (ESAs) and recombinant human erythropoietin have been used widely in renal anemia treatment. Recently, hypoxia-inducible factor-prolyl hydroxylase domain inhibitors (HIF-PHIs) that may improve the treatment of renal anemia patients were launched. Previous studies indicated that HIF-PHIs may decrease hepcidin levels and modulate iron metabolism, thereby increasing total iron-binding capacity and reducing the need for iron supplementation. Furthermore, HIF-PHIs can reduce inflammation and oxidative stress in CKD. Recombinant erythropoietin has become a routine treatment for patients with CKD and end-stage renal disease with relatively few adverse effects. However, higher doses of recombinant erythropoietin have been demonstrated to be an independent predictor of mortality in patients under hemodialysis. Phase III clinical trials of HIF-PHIs in patients with anemia and dialysis-dependent CKD have shown their efficacy and safety in both non-dialysis and dialysis CKD patients. However, HIFα binds to specific hypoxia-response elements in the vascular endothelial growth factor or retinoic acid-related orphan receptor gamma t (RORγt) promoter, which may be involved in the progression of cancer, psoriasis, and rheumatoid arthritis. In this paper, we have summarized the mechanism, clinical application, and clinical trials of HIF-PHIs in the treatment of renal anemia and aimed to provide an overview of the new drugs in clinical practice, as well as reconsider the advantages and disadvantages of HIF-PHIs and ESAs. Presently, there are not enough clinical studies examining the effects of long-term administration of HIF-PHIs. Therefore, further studies will be needed.

Association of Coding Variants in Hydroxysteroid 17-beta Dehydrogenase 14 (HSD17B14) with Reduced Progression to End Stage Kidney Disease in Type 1 Diabetes

BACKGROUND

Rare variants in gene coding regions likely have a greater impact on disease-related phenotypes than common variants through disruption of their encoded protein. We searched for rare variants associated with onset of ESKD in individuals with type 1 diabetes at advanced kidney disease stage.

METHODS

Gene-based exome array analyses of 15,449 genes in five large incidence cohorts of individuals with type 1 diabetes and proteinuria were analyzed for survival time to ESKD, testing the top gene in a sixth cohort (n=2372/1115 events all cohorts) and replicating in two retrospective case-control studies (n=1072 cases, 752 controls). Deep resequencing of the top associated gene in five cohorts confirmed the findings. We performed immunohistochemistry and gene expression experiments in human control and diseased cells, and in mouse ischemia reperfusion and aristolochic acid nephropathy models.

RESULTS

Protein coding variants in the hydroxysteroid 17-β dehydrogenase 14 gene (HSD17B14), predicted to affect protein structure, had a net protective effect against development of ESKD at exome-wide significance (n=4196; P value=3.3 × 10-7). The HSD17B14 gene and encoded enzyme were robustly expressed in healthy human kidney, maximally in proximal tubular cells. Paradoxically, gene and protein expression were attenuated in human diabetic proximal tubules and in mouse kidney injury models. Expressed HSD17B14 gene and protein levels remained low without recovery after 21 days in a murine ischemic reperfusion injury model. Decreased gene expression was found in other CKD-associated renal pathologies.

CONCLUSIONS

HSD17B14 gene is mechanistically involved in diabetic kidney disease. The encoded sex steroid enzyme is a druggable target, potentially opening a new avenue for therapeutic development.

Vitamin B6 in Health and Disease

Vitamin B6 is a fascinating molecule involved in the vast majority of changes in the human body because it is a coenzyme involved in over 150 biochemical reactions. It is active in the metabolism of carbohydrates, lipids, amino acids, and nucleic acids, and participates in cellular signaling. It is an antioxidant and a compound with the ability to lower the advanced glycation end products (AGE) level. In this review, we briefly summarize its involvement in biochemical pathways and consider whether its deficiency may be associated with various diseases such as diabetes, heart disease, cancer, or the prognosis of COVID-19.

Changes in Oxidative and Nitrosative Stress Indicators and Vascular Endothelial Growth Factor After Maximum-Intensity Exercise Assessing Aerobic Capacity in Males With Type 1 Diabetes Mellitus

In type 1 diabetes mellitus (T1DM), chronic hyperglycemia causes reactive oxygen and nitrogen species production. Exercise alters the oxidant-antioxidant balance. We evaluated the aerobic capacity and oxidant-antioxidant balance changes after maximum-intensity exercise in T1DM patients. The study involved 30 T1DM participants and 23 controls. The patients' average age was 23.4 ± 5.1 years, with a body mass index of 24.3 ± 3.1 kg m-2 and with satisfactory glycemic control. Among the controls, the respective values equaled 24.7 ± 2.9 years and 22.9 ± 2.1 kg m-2. Aerobic capacity was assessed with a treadmill test. Peak minute oxygen uptake was significantly lower in T1DM compared with the controls (44.7 ± 5.7 vs. 56.0 ± 7.3 mL kg-1 min-1). The total oxidant capacity measured by total oxidative status/total oxidative capacity (TOS/TOC) equaled 321.5 ± 151 μmol L-1 before and 380.1 ± 153 μmol L-1 after exercise in T1DM, and 164.1 ± 75 and 216.6 ± 75 μmol L-1 in the controls (p < 0.05 for all comparisons). A significant difference in the ratio of total antioxidant status/total antioxidant capacity (TAS/TAC) between the groups after the treadmill test was observed (p < 0.05). Nitrosative stress indicators where significantly higher in the T1DM group both before and after the exercise. In conclusion, diabetic patients demonstrated a lower aerobic capacity. The TOS/TOC and nitrosative stress indicators were significantly higher in T1DM before and after the test.

Heterogeneous long-term trajectories of glycaemic control in type 1 diabetes

AIMS

We aimed to identify long-term HbA1c trajectories and examine associated characteristics in an observational, childhood-onset (<17 years) type 1 diabetes cohort.

METHODS

Data are from the Epidemiology of Diabetes Complications study, comprising 405 participants with ≥2 of seven possible HbA1c measurements over follow-up (1988-2013) and available DNA (baseline mean diabetes duration 21 years, 53% men). HbA1c trajectories were estimated using latent class growth models. Baseline and change in participant characteristics were compared across trajectories.

RESULTS

Five HbA1c trajectories were identified: low (51%), intermediate stable (22%), improved (19%), high stable (6%), and worsened (2%; not included in analyses). Age, diabetes duration, diabetes onset age, and sex did not differ across trajectories. Characteristics did not differ significantly between intermediate stable and low trajectories at baseline, though albumin excretion rate (AER, p = 0.0002) and estimated glomerular filtration rate (eGFR, p = 0.001) worsened slightly more in intermediate stable over time. Improved and high stable trajectories had higher baseline LDL-c (p = 0.002 and 0.003, respectively). Improved trajectory increased median self-monitoring of blood glucose from <1 to 3.5 times/day (p < 0.0001) and had larger LDL-c improvement (p = 0.004) but greater worsening of AER (p < 0.0001) and eGFR (p < 0.0001) than low. The A allele of rs12970134 (near MC4R) was associated with improved (p = 0.0003) or high stable (p = 0.001) HbA1c trajectory, both patterns with high baseline HbA1c.

CONCLUSIONS

Long-term HbA1c trajectories were primarily associated with modifiable factors in this type 1 diabetes cohort. The intermediate stable pattern had a risk factor profile that suggests some protection against adverse metabolic effects of chronic hyperglycaemia, warranting further study.

Noninvasive OCT angiography-based blood attenuation measurements correlate with blood glucose level in the mouse retina

In this study, we investigated the correlation of the blood optical attenuation coefficient (OAC) and the blood glucose concentration (BGC). The blood OAC was measured in mouse retina in vivo by analyzing the depth attenuation of backscattered light under the guidance of OCT angiography (OCTA) vascular mapping, and then its correlation to the BGC was further investigated. The optical attenuation of the blood components presented a more reliable correlation to BGC than that of the background tissues. The arteries and veins presented a blood OAC change of ∼0.05-0.07 mm^-1 per 10 mg/dl and a significant (P < 0.001) elevation of blood OAC in diabetic mice was observed. Furthermore, different kinds of vessels also presented different performances. The veins had a higher correlation coefficient (R=0.86) between the measured blood OAC and BGC than that of the arteries (R=0.73). Besides, the blood OAC changes of the specific vessels occur without any obvious change in the vascular morphology in the retina. The blood OAC-BGC correlation suggests a concept of non-invasive OCTA-based glucometry, allowing a fast assessment of the blood glucose of specific vessels with superior motion immunity. A direct glucometry of the retina would be helpful for accurately monitoring the progression of diabetic retinopathy.

Relationship between soluble protein ST2 (sST2) levels and microvascular complications in a cohort of patients with type 1 diabetes

AIM

To determine the association and the prognostic value of soluble ST2 (sST2) levels in the development of diabetic retinopathy (DR), diabetic macular oedema (DMO) or diabetic nephropathy (DN), in a cohort of patients with type 1 diabetes (T1D).

METHODS

A total of 269 individuals with T1D (154 males and 115 females) were recruited. The overall mean age was 43.2±14.9 years, and the diabetes duration was 17.1±12.1 years. Levels of sST2 in serum were evaluated, and the presence as well as the degree of DR, DMO and DN was recorded. Additionally, other clinical and analytical parameters including demographic variables were recovered from patients' electronic health record. Ten years later, the presence and stage of DR, DMO and DN were again recorded under the same criteria. The association between previously mentioned parameters with DR and DN was analysed by univariate and multivariate logistic regression. The variables in the final multivariate models were adjusted from complete models via backward elimination and maintained only when significant.

RESULTS

An increase of 10ng/ml in the levels of sST2 was associated with a 1.50 (1.02-2.19) and 1.48 (1.05-2.08) prevalence odds ratio (OR) in DMO and DR, respectively. There was no association between sST2 levels and DN. Meanwhile, sST2 levels did not display a prognostic effect in any of the microangiopathic diabetic complications studied.

CONCLUSIONS

Levels of sST2 are associated with the presence of DR and DMO, they do not seem to be predictive for the development or deterioration of DR, DMO or DN.

Residual β-Cell Function in Type 1 Diabetes Followed for 2 Years after 3C Study

OBJECTIVE

To investigate the natural history and related factors of the pancreatic β-cell function in Chinese type 1 diabetic patients from 3C study Shantou center.

METHOD

Stimulated C-peptide levels from follow-up data of 201 individuals in 3C study Shantou subgroup starting in 2012 were used. Residual β-cell function was defined as stimulated C - peptide level ≥ 0.2 pmol/mL, on the basis of cut-points derived from the Diabetes Control and Complications Trial (DCCT).

RESULTS

36.8% of patients had residual β-cell function, and the percentage was 68.2% in newly diagnosed diabetic patients. COX regression analysis indicated that the age of diagnosis, HbA1C level, and duration were independent factors of residual β-cell function in individuals with ≤5 years duration, but in those with duration ≥5 years, only the age of diagnosis was a predictor. The pancreatic β-cell function mainly declined in the first 5 years of the duration, and the rate of decline was correlated negatively with the duration and age of diagnosis. Receiver operating characteristic (ROC) analysis indicated that the cut-off point of stimulated C-peptide was 0.615 pmol/mL in patients with <5 years duration to have 7% HbA1c.

CONCLUSION

Age at diagnosis was the strongest predictor for residual C-peptide. There was a more rapid decline of stimulated C-peptide in duration ≤5 years and younger patients. Therefore, intervention therapies of β-cells should start from the early stage, and the recommended target goal of stimulated C-peptide is 0.615 pmol/mL or above.

Diagnosis and management of pediatric type 1 diabetes mellitus

Background: In contrast to type 2 diabetes, type 1 diabetes mellitus (T1DM) requires insulin treatment to control blood glucose. As the incidence and prevalence of T1DM have steadily increased; therefore, T1DM is increasingly being diagnosed not only in children and adolescents, but also in adults. Therefore, the importance of accurate diagnosis and optimal management of T1DM is being recognized in clinical practice.Current Concepts: T1DM is caused by insulin deficiency, following the destruction of insulin-producing pancreatic β-cells. Diagnosis of diabetes is based on the following criteria: fasting blood glucose levels ≥126 mg/dL, random blood glucose levels ≥200 mg/dL accompanied by symptoms of hyperglycemia, an abnormal 2-hour oral glucose tolerance test, or glycated hemoglobin ≥6.5%. Accurate diagnosis of T1DM based on patients’ clinical characteristics, serum C-peptide levels, and detection of autoantibodies against β-cell autoantigens is important for optimum care and to avoid complications. A target glycated hemoglobin level is recommended in children, adolescents, and young adults with access to comprehensive care. The availability of insulin analogues and mechanical technologies (insulin pumps and continuous glucose monitors) has improved the management of T1DM, and these are useful for the prevention of microvascular complications. Screening for microvascular complications should commence at puberty or 5 years after diagnosis of T1DM.Discussion and Conclusion: Effective cooperation and coordination between patient, parents, and healthcare providers are necessary to achieve a successful transition from pediatric to adult care in patients with T1DM. Diabetic management for T1DM should be individualized based on patients’ lifestyle, as well as psychosocial, and medical circumstances.

Discoveries from the study of longstanding type 1 diabetes

Award programmes that acknowledge the remarkable accomplishments of long-term survivors with type 1 diabetes have naturally evolved into research programmes to determine the factors associated with survivorship and resistance to chronic complications. In this review, we present an overview of the methodological sources of selection bias inherent in survivorship research (selection of those with early-onset diabetes, incidence-prevalence bias and bias from losses to follow-up in cohort studies) and the breadth and depth of literature focusing on this special study population. We focus on the learnings from the study of longstanding type 1 diabetes on discoveries about the natural history of insulin production loss and microvascular complications, and mechanisms associated with them that may in future offer therapeutic targets. We detail descriptive findings about the prevalence of preserved insulin production and resistance to complications, and the putative mechanisms associated with such resistance. To date, findings imply that the following mechanisms exist: strategies to maintain or recover beta cells and their function; activation of specific glycolytic enzymes such as pyruvate kinase M2; modification of AGE production and processing; novel mechanisms for modification of renin-angiotensin-aldosterone system activation, in particular those that may normalise afferent rather than efferent renal arteriolar resistance; and activation and modification of processes such as retinol binding and DNA damage checkpoint proteins. Among the many clinical and public health insights, research into this special study population has identified putative mechanisms that may in future serve as therapeutic targets, knowledge that likely could not have been gained without studying long-term survivors.

Association of Cognitive Function and Retinal Neural and Vascular Structure in Type 1 Diabetes

CONTEXT

Cognitive dysfunction is a growing and understudied public health issue in the aging type 1 diabetic population and is difficult and time-consuming to diagnose. Studies in long duration type 1 diabetes have reported the presence of proliferative diabetic retinopathy was associated with cognitive dysfunction.

OBJECTIVE

This study assessed whether structural and vascular abnormalities of the retina, representing an extension of the central nervous system, are associated with cognitive impairment and other complications of type 1 diabetes.

METHODS

An observational cross-sectional study of individuals with 50 or more years of type 1 diabetes (Joslin Medalist Study) was conducted at a university hospital in the United States. The study included 129 participants with complete cognitive testing. Validated cognitive testing measures included psychomotor speed, and immediate, and delayed memory. Optical coherence tomography (OCT) and OCT angiography (OCTA) were performed to obtain neural retinal layer thicknesses and vascular density for superficial (SCP) and deep retinal capillary plexus (DCP). Multivariable modeling was adjusted for potential confounders associated with outcomes in unadjusted analyses.

RESULTS

Decreased vessel density of the SCP and DCP was associated with worse delayed memory (DCP: P = .002) and dominant hand psychomotor speed (SCP: P = .01). Thinning of the retinal outer nuclear layer was associated with worse psychomotor speed both in nondominant and dominant hands (P = .01 and P = .05, respectively). Outer plexiform layer thickness was associated with delayed memory (P = .04).

CONCLUSION

These findings suggest that noninvasive retinal imaging using OCT and OCTA may assist in estimating the risks for cognitive dysfunction in people with type 1 diabetes.

Circulating miRNAs in diabetic retinopathy patients: Prognostic markers or pharmacological targets?

In this study we analyzed the expression of circulating miRNAs, in the serum of diabetic retinopathy (DR) patients. Five miRNAs (hsa-miR-195-5p, hsa-miR-20a-5p, hsa-miR-20b-5p, hsa-miR-27b-3p and hsa-miR-451a) were validated as biomarkers for stratification of DR stages, from the early non-proliferative (NPDR) to the late proliferative (PDR) phase. Furthermore, circulating levels of these miRNAs correlated with retinal hyper-reflective spots (HRS), assessed by optical coherence tomography (OCT). The number of HRS increased with worsening of DR stages. On the contrary, no significant vascular density differences between NPDR and PDR patients were detected by angio-OCT (OCTA). A post-hoc bioinformatics analysis associated these five miRNAs to target genes belonging to the "Tumor Necrosis Factor alfa signaling" pathway, and several molecules were predicted to modify miRNAs expression. In conclusion, correlation between specific circulating miRNAs and intraretinal hyper-reflective spots was demonstrated, confirming that these miRNAs were validated as prognostic biomarkers, and also as potential pharmacological targets, warranting further clinical evaluation to explore novel therapeutics for diabetic retinopathy.

CaM Kinase II-δ Is Required for Diabetic Hyperglycemia and Retinopathy but Not Nephropathy

Type 2 diabetes has become a pandemic and leads to late diabetic complications of organs, including kidney and eye. Lowering hyperglycemia is the typical therapeutic goal in clinical medicine. However, hyperglycemia may only be a symptom of diabetes but not the sole cause of late diabetic complications; instead, other diabetes-related alterations could be causative. Here, we studied the role of CaM kinase II-δ (CaMKIIδ), which is known to be activated through diabetic metabolism. CaMKIIδ is expressed ubiquitously and might therefore affect several different organ systems. We crossed diabetic leptin receptor-mutant mice to mice lacking CaMKIIδ globally. Remarkably, CaMKIIδ-deficient diabetic mice did not develop hyperglycemia. As potential underlying mechanisms, we provide evidence for improved insulin sensing with increased glucose transport into skeletal muscle and also reduced hepatic glucose production. Despite normoglycemia, CaMKIIδ-deficient diabetic mice developed the full picture of diabetic nephropathy, but diabetic retinopathy was prevented. We also unmasked a retina-specific gene expression signature that might contribute to CaMKII-dependent retinal diabetic complications. These data challenge the clinical concept of normalizing hyperglycemia in diabetes as a causative treatment strategy for late diabetic complications and call for a more detailed analysis of intracellular metabolic signals in different diabetic organs.

Role of Glucose Metabolism and Mitochondrial Function in Diabetic Kidney Disease

PURPOSE OF REVIEW

Diabetic kidney disease (DKD) continues to be the primary cause of chronic kidney disease in the USA and around the world. The numbers of people with DKD also continue to rise despite current treatments. Certain newer hypoglycemic drugs offer a promise of slowing progression, but it remains to be seen how effective these will be over time. Thus, continued exploration of the mechanisms underlying the development and progression of DKD is essential in order to discover new treatments. Hyperglycemia is the main cause of the cellular damage seen in DKD. But, exactly how hyperglycemia leads to the activation of processes that are ultimately deleterious is incompletely understood.

RECENT FINDINGS

Studies primarily over the past 10 years have provided novel insights into the interplay of hyperglycemia, glucose metabolic pathways, mitochondrial function, and the potential importance of what has been called the Warburg effect on the development and progression of DKD. This review will provide a brief overview of glucose metabolism and the hypotheses concerning the pathogenesis of DKD and then discuss in more detail the supporting data that indicate a role for the interplay of glucose metabolic pathways and mitochondrial function.

Protection from neuropathy in extreme duration type 1 diabetes

A proportion of individuals with type 1 diabetes mellitus for more than 50 years (medallists) may be protected from developing nephropathy, retinopathy and neuropathy. Detailed neuropathy phenotyping was undertaken in a cohort of 33 medallists aged 63.7 ± 1.4 years with diabetes for 58.5 ± 0.8 years and HbA1c of 65.9 ± 2.1 mmol/mmol. Medallists had a significantly higher HbA1c (P < .001), lower estimated glomerular filtration rate (eGFR) (P = .005) and higher albumin creatinine excretion ratio (ACR) (P = .01), but a lower total cholesterol (P < .001), triacylglycerols (P = .001), low density lipoprotein‐cholesterol (P < .001) and higher high density lipoprotein‐cholesterol (P = .03), compared to controls. Twenty‐four percent of participants were identified as “escapers” without confirmed diabetic neuropathy. They had a lower neuropathy symptom profile (P = .002), vibration perception threshold (P = .02), warm threshold (P = .05), higher peroneal amplitude (P = .005), nerve conduction velocity (P = .03), heart rate variability (P = .001), corneal nerve fibre density (P = 0.001), branch density (P < .001) and length (P = .001), compared to medallists with diabetic neuropathy. Escapers had a shorter duration of diabetes (P = .006), lower alcohol consumption (P = .04), lower total cholesterol (P = .04) and LDL (P = .02), higher eGFR (P = .001) and lower ACR (P < .001). Patients with extreme duration diabetes without diabetic neuropathy have a comparable HbA1c, blood pressure and body mass index, but a more favourable lipid profile and consume less alcohol compared to those with diabetic neuropathy.

Direct and indirect therapeutic effect of traditional Chinese medicine as an add-on for non-proliferative diabetic retinopathy: a systematic review and meta-analysis

Background

Diabetic retinopathy (DR) is the leading cause of blindness in many countries. The current treatment for non-proliferative DR (NPDR) using Western medicine (WM) alone is insufficient. At present, the combination of NPDR treatment with traditional Chinese medicine (TCM) and WM is universally applied. We aimed to evaluate the effectiveness and safety of TCM as an add-on for NPDR using a systematic review and meta-analysis.

Method

Data from randomized controlled trials (RCTs) of TCM for NPDR treatment along with WM before July 6, 2019, were collected from the China National Knowledge Infrastructure, Wanfang Database, China Biomedical Database, Pubmed, Embase, and Cochrane Library. Relevant data were extracted by two reviewers. I² statistics was adopted to appraise heterogeneity. If I² < 50% the fixed-effects model was employed, otherwise a random-effect model was employed. (PROSPERO: CRD42019134947)

Result

Eighteen RCTs (1522 patients) were included based on the inclusion and exclusion criteria. The results showed that compared with WM alone, TCM (including Compound Xueshuantong Capsule, Qiming Granule, and others) combined with WM for NPDR could improve the overall effiicacy [n = 1686, RR 1.24 (1.18,1.30), P < 0.00001, I² = 0%], and reduce the influence of risk factors related to NPDR, such as glycated hemoglobin level [n = 360, MD − 0.85 (− 1.28, − 0.41), P = 0.0001, I² = 72%], triglyceride (P < 0.00001), and total cholesterol (P = 0.0008). Moreover, no serious adverse events were reported.

Conclusion

Compared with WM alone, TCM + WM could significantly improve NPDR and also reduce the correlation levels of risk factors, such as hyperglycemia, dyslipidemia. However, the small sample included in the study might lead to a publication bias, and therefore, our results should be treated with caution.

Vitamin D Protects against Oxidative Stress and Inflammation in Human Retinal Cells

Diabetic retinopathy is a vision-threatening microvascular complication of diabetes and is one of the leading causes of blindness. Oxidative stress and inflammation play a major role in its pathogenesis, and new therapies counteracting these contributors could be of great interest. In the current study, we investigated the role of vitamin D against oxidative stress and inflammation in human retinal pigment epithelium (RPE) and human retinal endothelial cell lines. We demonstrate that vitamin D effectively counteracts the oxidative stress induced by hydrogen peroxide (H₂O₂). In addition, the increased levels of proinflammatory proteins such as Interleukin (IL)-6, IL-8, Monocyte chemoattractant protein (MCP)-1, Interferon (IFN)-γ, and tumor necrosis factor (TNF)-α triggered by lipopolysaccharide (LPS) exposure were significantly decreased by vitamin D addition. Interestingly, the increased IL-18 only decreased by vitamin D addition in endothelial cells but not in RPE cells, suggesting a main antiangiogenic role under inflammatory conditions. Moreover, H₂O₂ and LPS induced the alteration and morphological damage of tight junctions in adult retinal pigment epithelium (ARPE-19) cells that were restored under oxidative and inflammatory conditions by the addition of vitamin D to the media. In conclusion, our data suggest that vitamin D could protect the retina by enhancing antioxidant defense and through exhibiting anti-inflammatory properties.

Protective factors as biomarkers and targets for prevention and treatment of diabetic nephropathy: From current human evidence to future possibilities

Although hyperglycemia, high blood pressure and aging increase the risk of developing kidney complications, some diabetes patients exposed to these risk factors do not develop kidney disease, suggesting the presence of endogenous protective factors. There is a growing need to understand these factors determining protection of the kidney in order to improve the design of preventive strategies and to enhance the processes responsible for renoprotection. The aim of this review was to present the existing molecular and epidemiological data on factors showing protective effects in diabetic kidney disease, and to summarize the evidence regarding their potential in the area of future clinical diagnostics, therapeutics and early preventive strategies. These include transcriptomic and proteomic studies regarding the anti-inflammatory, anti-fibrotic and regenerative factors that were associated with slower progression of renal function loss. Another focus is the new evidence regarding the evaluation of alterations in the regulatory epigenome and its involvement in the risk of diabetic kidney disease. Further effort is required to validate and extend these findings, and to define their potential for clinical implementation in the future.

Progression of Diabetic Complications in Subgroups of People with Long Term Diabetes Type 1 According to Clinical Course

AIMS

Prevention and prediction of microvascular complications are important aims of medical care in people with type 1 diabetes. Since the course of the disease is heterogenous, we tried to identify subgroups with specific risk profiles for microvascular complications.

METHODS

Retrospective analysis of a cohort of 285 people (22637 consultations) with >10 years of type 1 diabetes. Persons were grouped into slow (<15 years), fast (>15 years) and non progressors according to the average onset of microvascular complications. Generalized estimating equations for binary outcomes were applied and pseudo coefficients of determination were calculated.

RESULTS

Progression to microvascular disease was associated with age (OR: 1.034 [1.001-1.068]; p=0.04), diabetes duration (OR: 1.057 [1.021-1.094]; p=0.002), HbA_1c (OR: 1.035 [1.011-1.060]; p=0.005), BMI (OR: 0.928 [0.866-0.994]; p=0.034) and the social strata index (OR: 0.910 [0.830-0.998]; p=0.046). Generalized estimating equations predicted 31.02% and exclusion of HbA_1c marginally reduced the value to 28.88%. The proportion of patients with LADA was higher in fast than slow progressors [13 (26.5%) vs. 14 (11.9%); p=0.019]. A generalized estimating equation comparing slow to fast progressors revealed no significant markers.

CONCLUSION

In our analysis, we were able to confirm known risk factors for microvascular disease in people with type 1 diabetes. Overall, prediction of individual risk was difficult, the effect of individual markers minor and we could not find differences regarding slow or fast progression. We therefore emphasis the need for additional markers to predict individual risk for microvascular disease.

Retinol binding protein 3 is increased in the retina of patients with diabetes resistant to diabetic retinopathy

The Joslin Medalist Study characterized people affected with type 1 diabetes for 50 years or longer. More than 35% of these individuals exhibit no to mild diabetic retinopathy (DR), independent of glycemic control, suggesting the presence of endogenous protective factors against DR in a subpopulation of patients. Proteomic analysis of retina and vitreous identified retinol binding protein 3 (RBP3), a retinol transport protein secreted mainly by the photoreceptors, as elevated in Medalist patients protected from advanced DR. Mass spectrometry and protein expression analysis identified an inverse association between vitreous RBP3 concentration and DR severity. Intravitreal injection and photoreceptor-specific overexpression of RBP3 in rodents inhibited the detrimental effects of vascular endothelial growth factor (VEGF). Mechanistically, our results showed that recombinant RBP3 exerted the therapeutic effects by binding and inhibiting VEGF receptor tyrosine phosphorylation. In addition, by binding to glucose transporter 1 (GLUT1) and decreasing glucose uptake, RBP3 blocked the detrimental effects of hyperglycemia in inducing inflammatory cytokines in retinal endothelial and Müller cells. Elevated expression of photoreceptor-secreted RBP3 may have a role in protection against the progression of DR due to hyperglycemia by inhibiting glucose uptake via GLUT1 and decreasing the expression of inflammatory cytokines and VEGF.

Is primary open-angle glaucoma a risk factor for diabetic retinopathy?

PURPOSE

To compare the prevalences of diabetic retinopathy in diabetes mellitus patients, with and without primary open-angle glaucoma, with a view to determine if glaucoma is a risk factor for the development of diabetic retinopathy.

METHODS

Cross-sectional, comparative study consisting of 86 diabetic patients with glaucoma matched with 86 diabetic patients without glaucoma. The two groups were matched by age, sex and duration of diabetes mellitus. Demographic data were obtained via patient medical records and self-administered questionnaires. Participants underwent a standardized examination protocol including blood pressure measurement and ocular examination. Main outcome measure was the presence of diabetic retinopathy.

RESULTS

Two hundred and ninety-two eyes (144 glaucomatous eyes and 148 non-glaucomatous eyes) of 172 participants with diabetes mellitus were assessed. The prevalence of diabetic retinopathy among 86 participants with glaucoma comorbidity was 23.6%, while the prevalence among 86 non-glaucomatous participants was 33.8% (p = 0.06). After the regression analysis, controlling for systemic and ocular risk factors for diabetic retinopathy, the odds of developing diabetic retinopathy were significantly higher in the glaucomatous eyes compared with eyes without glaucoma (OR: 2.75; p = 0.03; 95% CI: 1.10-6.87).

CONCLUSION

This study demonstrated that glaucomatous diabetic eyes were almost three times more likely to develop diabetic retinopathy compared to non-glaucomatous diabetic eyes. Prospective studies may be required to establish a risk-cause relationship. Ocular perfusion pressure control should be considered in patients with diabetes mellitus and glaucoma.

Subclinical macroangiopathic target organ damage in type 1 diabetes mellitus patients

PURPOSE

We have summarized key studies regarding the assessment of subclinical macroangiopathic target organ damage (TOD) in type 1 diabetes mellitus (T1DM).

RESULTS

Although chronic complications resulting from hyperglycemia, in particular macroangiopathies, are still the first cause of death in T1DM, there has been growing recognition of the role of hypoglycemia in cardiovascular morbidity and mortality. Subclinical TOD diagnosis ensures early implementation of the complex management aiming at either partial reversal of these complications or at least its downturn. To better identify patients with early TODs, several non-invasive diagnostic techniques are employed, including the ultrasonographic assessment of the intima-media thickness (IMT), computed tomography (CT) for coronary artery calcium (CAC) scores, and pulse wave velocity (PWV) measurement for arterial stiffness evaluation. Various studies reported that T1DM patients present an increased IMT. An increasing IMT fairly correlates with the cardiovascular (CV) events risk even after the adjustment to age, diabetes duration, quality of glucose control as well as the presence of hypertension, and chronic complications. Another, well established marker of the organ damage - CAC score is recommended by ACC/AHA guidelines to assess the overall CV risk in T1DM. Also, the arterial stiffness evaluation with PWV may further improve CV risk prediction, which has been reported in multiple studies including the Framingham Heart Study.

CONCLUSIONS

There is shortage of data from prospective studies which could confirm the benefits of early treatment initiation based on the presence of the subclinical organ damage in T1DM. Most evidence comes from T2DM trials, where effective preventive measures were identified i.e.: smoking cessation, reasonable blood glucose control, efficacious hypertension treatment, and dyslipidemia management, as well as renoprotection. There is still a field for further research to see if routine assessment of asymptomatic vascular damage and early implementation of aggressive treatment would reduce mortality excess from CVD in T1DM.

Case report on two diabetic donor eyes with no retinopathy: Clinicopathological and molecular studies

We were intrigued to analyze donor eyes of two individuals without retinopathy even after 40 years of type 2 diabetes mellitus. Targeted molecular factors associated with angiogenesis and the key antioxidant enzymes in retinal tissue were analyzed. Accordingly PEDF, Adiponectin and Paraoxonase 2 showed augmented mRNA expression in both the retina with no significant change in VEGF expression. Vitreous showed increased PEDF protein in donor 1 and Adiponectin in donor 2 with no change in VEGF protein. This study highlights the profile of specific molecular factors that contribute to the non-development of diabetic retinopathy changes in these individuals.

The Usefulness of Serum Biomarkers in the Early Stages of Diabetic Retinopathy: Results of the EUROCONDOR Clinical Trial

The main aim of this study was to evaluate the ability of serum biomarkers to predict the worsening of retinal neurodysfunction in subjects with type 2 diabetes. For this purpose, we measured selected molecules (N-epsilon-carboxy methyl lysine (CML), laminin P1 (Lam-P1), and asymmetric dimethylarginine (ADMA)) in the serum of 341 participants of the EUROCONDOR study at baseline, 24, and 48 weeks. Retinal neurodysfunction was assessed by measuring implicit time (IT) using multifocal electroretinography, and structural changes were examined by spectral domain–optical coherence tomography. The values of IT at baseline were directly correlated with baseline serum concentrations of CML (r = 0.135, p = 0.013). Furthermore, in the placebo group, increase in CML concentration throughout follow-up correlated with the IT (r = 0.20; p = 0.03). Baseline serum levels of CML also correlated with macular retinal thickness (RT) (r = 0.231; p < 0.001). Baseline Lam-P1 levels correlated with the increase of the RT at the end of follow-up in the placebo group (r = 0.22; p = 0.016). We provide evidence that CML may be a biomarker of both retinal neurodysfunction and RT, whereas Lam-P1 was associated with RT only. Therefore, circulating levels of these molecules could provide a complementary tool for monitoring the early changes of diabetic retinopathy (DR).

Living Well With Type 1 Diabetes for 40 Years or More

Background

Although many studies explore the experiences of persons with type 1 diabetes, most examine the experience of children, adolescents, or persons in transition to adulthood. Few studies focus on the person living long term with type 1 diabetes.

Purpose

The purpose of this study was to explore the facilitators and barriers for people living well with type 1 diabetes over the long term.

Methods

An inductive interpretive description approach was used to explore living with type 1 diabetes for a duration of 40 years or more. Qualitative semistructured interviews with a convenience sample (n = 8) were conducted.

Results

Four dialectic themes were identified: accommodating and battling the disease, convenience and constraint of technology and treatment, self-reliance and reliance on others, and external and personal knowledge.

Conclusions

Recommendations for the health-care team emphasize person-centered care with acknowledgment of the person as expert and as more than their condition. Further research with this population would strengthen the implications for practice. Specifically, research is needed on diabetes distress, losses experienced due to diabetes, how to meet their educational needs, and how to tap into their expertise for the benefit of those with type 1 following them.

Factors associated with resistance to complications in long-standing type 1 diabetes in China

OBJECTIVE

Type 1 diabetes (T1DM) is associated with a higher risk of premature death, but there are factors in certain patients with T1DM that protect them from complications and premature death. These factors had not been identified in non-Caucasian populations, so we aimed to identify factors that protect against the development of diabetic nephropathy (DN) and diabetic retinopathy (DR) in long-standing T1DM in China

METHODS

Ninety-five T1DM patients with >30 years’ duration of diabetes were enrolled in this nationwide study. Differences between groups of patients with and without complications were compared, and multivariable regression analysis was used to evaluate the relationships between candidate protective factors and the development of DN or DR.

RESULTS

Thirty of the participants did not have DN and the same amount did not have DR. 6/52 of participants without DN were from a rural area, whereas 11/28 of participants with DN had been born in a rural area (P = 0.005). Systolic blood pressure (SBP) was higher in participants with DN (135 ± 26 mmHg vs 121 ± 13 mmHg; P = 0.002). In participants without DR, 27/30 were married or cohabitating, and only 3/30 were single, never married, or widowed, but for those with proliferative DR (PDR), 13/26 had been married (P = 0.003). A rural or urban origin and SBP were associated with DN in the multivariable analysis.

CONCLUSION

we have shown that higher socioeconomic status, indicated by birth in an urban area, and being married or cohabitating, are accompanied by better blood pressure control and a lower risk of microvascular complications in Chinese patients with long-standing T1DM. These findings illustrate the importance of improving care for patients with T1DM in China.

Attenuation of diabetic retinopathy and neuropathy by resveratrol: Review on its molecular mechanisms of action

Resveratrol is an important phenolic phytochemical from the therapeutic perspective. It has therapeutic impacts over wide range of diseases, especially the ones related to oxidative stress. Resveratrol, being primarily a potent anti-oxidant phytochemical, has significant impact against major diseases as inflammatory disorders, diabetes, and cancer. In the current review article, we intend to highlight the molecular aspects of the mechanism of action of resveratrol against major diabetic implications, namely, retinopathy and neuropathy. Both these diabetic implications are among the first fallouts of chronic hyperglycaemia. Resveratrol, via multiple molecular pathways, tend to attenuate and reverse these deformity and other disease-causing implications.

Morphofunctional analysis of the retina in patients with type 1 diabetes without complications after 30 years of disease

There is a lack of studies evaluating the sub-clinical retinal changes in patients with long-term type 1 diabetes mellitus (T1DM) and without history of systemic/ocular complications. The aim of this cross-sectional study was to investigate sub-clinical structural and/or vascular retinal changes in patients with long-term (≥30 years) T1DM and without systemic/ocular complications ("happy few" patients) using structural optical coherence tomography (OCT), OCT-angiography and microperimetry. Twelve eyes of 12 consecutive T1DM patients (mean age 52 ± 12 years, mean duration of disease 35 ± 3 years, mean HbA1c level 7.3 ± 2.8%), without micro/macrovascular complications associated with long-standing T1DM, and twelve healthy subjects were consecutively included. No statistically significant differences were disclosed comparing patients and controls for age, sex, best-corrected visual acuity, central macular thickness, and choroidal thickness. Using OCT-angiography, we did not find any significant difference in foveal avascular zone area, perfusion density, vessel length density, and tortuosity. Moreover, no significant differences were disclosed in retinal nerve fiber layer and ganglion cell complex thickness using structural OCT. No differences were disclosed in retinal sensitivity by microperimetry. New diagnostic tools are able to confirm the presence of a particular population of patients with type 1 diabetes who have been completely spared from diabetic retinal complications. The finding of these "happy few" patients could help us to better understand and target future treatments for diabetes.