Complete loss of insulin secretion capacity in type 1A diabetes patients during long-term follow up

β-cell neogenesis: A rising star to rescue diabetes mellitus

BACKGROUND

Diabetes Mellitus (DM), a chronic metabolic disease characterized by elevated blood glucose, is caused by various degrees of insulin resistance and dysfunctional insulin secretion, resulting in hyperglycemia. The loss and failure of functional β-cells are key mechanisms resulting in type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM).

AIM OF REVIEW

Elucidating the underlying mechanisms of β-cell failure, and exploring approaches for β-cell neogenesis to reverse β-cell dysfunction may provide novel strategies for DM therapy.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Emerging studies reveal that genetic susceptibility, endoplasmic reticulum (ER) stress, oxidative stress, islet inflammation, and protein modification linked to multiple signaling pathways contribute to DM pathogenesis. Over the past few years, replenishing functional β-cell by β-cell neogenesis to restore the number and function of pancreatic β-cells has remarkably exhibited a promising therapeutic approach for DM therapy. In this review, we provide a comprehensive overview of the underlying mechanisms of β-cell failure in DM, highlight the effective approaches for β-cell neogenesis, as well as discuss the current clinical and preclinical agents research advances of β-cell neogenesis. Insights into the challenges of translating β-cell neogenesis into clinical application for DM treatment are also offered.

Metabolic signatures of β-cell destruction in type 1 diabetes

AIMS/INTRODUCTION

In the development of type 1 diabetes, metabolites are significantly altered and might be involved in β-cell destruction and protection. We aimed to identify new metabolic markers of β-cell destruction in type 1 diabetes patients.

MATERIALS AND METHODS

A total of 33 participants were recruited for this cross-sectional observational study: 23 with type 1 diabetes, seven with type 2 diabetes and three healthy controls. Those with type 1 diabetes were further subdivided into three groups: new-onset, microsecretors and complete lack of endogenous insulin in type 1 diabetes.

RESULTS

Metabolomic analysis identified a total of 737 peaks, and partial least square analysis was successful in discriminating between the three groups of type 1 diabetes. Among the factor loadings discriminating type 1 diabetes, 3-phenylpropionic acid (r = 0.80, P = 4.7E^-6 ) and hypotaurine (r = -0.484, P = 1.9E^-2 ) strongly contributed to identifying new-onset type 1 diabetes, and 5-methylcytosine to identifying complete-lack type 1 diabetes (r = 0.586, P = 6.5E^-3 ). Reporter operating characteristics analysis, including all type 1 diabetes, type 2 diabetes and healthy controls, showed that high 3-phenylpropionic acid (Pc <0.0001) and low hypotaurine (Pc <0.0001) were useful for identifying new-onset type 1 diabetes, and high 5-methylcytosine (Pc = 0.002) for the complete-lack type 1 diabetes.

CONCLUSIONS

In the present study, metabolic signatures were shown to be useful in identifying type 1 diabetes at different clinical stages, and 3-phenylpropionic acid and hypotaurine are novel biomarkers for identifying new-onset type 1 diabetes, suggesting the involvement of the gut bacterial environment, anti-oxidant mechanisms through the hypotaurine-taurine pathway and methylated deoxyribonucleic acid fragmentation in the process of β-cell destruction.

Insulin-dependent diabetes mellitus in older adults: Current status and future prospects

The recent increase in life expectancy has resulted in an increase in the number of older adults with diabetes mellitus. In addition to type 2 diabetes, in which aging is a well‐known risk factor, individuals with type 1 and other types of diabetes are also increasing owing to longevity in the general population and improved prognosis of the disease and comorbidities. Insulin‐dependent state in type 1 diabetes and other types of diabetes, such as diabetes after pancreatectomy, inevitably requires insulin treatment for survival; however, daily injection of insulin is often hampered in older adults due to impaired cognitive function or limited activities of daily living. In this review, we aimed to discuss the current situation of insulin‐dependent diabetes mellitus in older adults and highlight future prospects. Geriatr Gerontol Int 2022; 22: 549–553.

New Advances on Pathophysiology of Diabetes Neuropathy and Pain Management: Potential Role of Melatonin and DPP-4 Inhibitors

Pre-diabetes and diabetes are growing threats to the modern world. Diabetes mellitus (DM) is associated with comorbidities such as hypertension (83.40%), obesity (90.49%), and dyslipidemia (93.43%), creating a substantial burden on patients and society. Reductive and oxidative (Redox) stress level imbalance and inflammation play an important role in DM progression. Various therapeutics have been investigated to treat these neuronal complications. Melatonin and dipeptidyl peptidase IV inhibitors (DPP-4i) are known to possess powerful antioxidant and anti-inflammatory properties and have garnered significant attention in the recent years. In this present review article, we have reviewed the recently published reports on the therapeutic efficiency of melatonin and DPP-4i in the treatment of DM. We summarized the efficacy of melatonin and DPP-4i in DM and associated complications of diabetic neuropathy (DNP) and neuropathic pain. Furthermore, we discussed the mechanisms of action and their efficacy in the alleviation of oxidative stress in DM.

β-Cell failure in diabetes: Common susceptibility and mechanisms shared between type 1 and type 2 diabetes

Diabetes mellitus is etiologically classified into type 1, type 2 and other types of diabetes. Despite distinct etiologies and pathogenesis of these subtypes, many studies have suggested the presence of shared susceptibilities and underlying mechanisms in β-cell failure among different types of diabetes. Understanding these susceptibilities and mechanisms can help in the development of therapeutic strategies regardless of the diabetes subtype. In this review, we discuss recent evidence indicating the shared genetic susceptibilities and common molecular mechanisms between type 1, type 2 and other types of diabetes, and highlight the future prospects as well.

Glucagon stimulation test as a possible predictor of residual β-cell function

BACKGROUND

We aimed to investigate the significance of the C-peptide levels on a glucagon stimulation test (GST) conducted soon after diagnosis as a predictive marker for residual β-cell function over time in Japanese children with type 1 diabetes (TD1).

METHODS

We retrospectively enrolled 65 Japanese children (25 male, 40 female; age <16 years) with new-onset TD1. A GST was conducted within 1 month of diagnosis, when glucose toxicity improved. One- to 2-h postprandial serum C-peptide values were measured at 0, 3, 6, 12, 24, 36, 60, and 120 months after diagnosis.

RESULTS

Receiver operating characteristic analysis showed that the cutoff values of peak serum C-peptide levels used to predict the complete destruction of β-cells at 3, 6, and 12 months after diagnosis were all 0.20 ng/mL (area under the curve [AUC] 0.867, 95% confidence interval [CI] 0.745-0.990; AUC 0.774, 95% CI 0.634-0.914; and AUC 0.804, 95% CI 0.695-0.914, respectively); the values at 24, 36, and 60 months were 0.69 ng/mL (AUC 0.828, 95% CI 0.721-0.936), 0.60 ng/mL (AUC 0.777, 95% CI 0.636-0.918), and 0.70 ng/mL (AUC 0.848, 95% CI 0.715-0.982), respectively. On multivariate analysis, peak serum C-peptide level on a GST, diabetic ketoacidosis, age, and HbA1c level at diagnosis were associated with residual β-cell function over time.

CONCLUSIONS

Peak serum C-peptide levels on a GST conducted soon after diagnosis in Japanese children with TD1 could predict the time to decrease in postprandial serum C-peptide values to < 0.20 ng/mL.

Residual β-cell function after 10 years of autoimmune type 1 diabetes: prevalence, possible determinants, and implications for metabolism

Background

Type 1 diabetes (T1D) has long been considered a progressive autoimmune disease resulting in the failure of pancreatic β-cell function and absolute endogenous insulin deficiency. However, several studies have demonstrated patients with T1D have detectable C-peptide levels long after diagnosis, which has remarkable clinical significance. Since this issue has not been systematically explored in non-Caucasian populations, we aimed to identify the prevalence of residual β-cell function and its related clinical features in Chinese long-term T1D patients.

Methods

We enrolled 109 patients with T1D for ≥10 years and administered a mixed-meal tolerance test (MMTT). Fasting and postprandial C-peptide (FCP/PCP) levels were measured to evaluate the insulin secretion function of β-cells. Patients whose FCP and PCP levels were both below the lower detection limit (16.7 pmol/L) were grouped as ‘β-cell function depleted’, while others were thought to have ‘residual β-cell function’. Demographic data, metabolic status, and diabetic complications were compared between patients with or without residual β-cell function.

Results

38.5% of subjects retained residual β-cell function, and among those, 33.3% responded to MMTT by a two-fold or greater rise of their FCP levels. Clinical features associated with residual β-cell function were older age of diagnosis [27.5 (interquartile range:11.5–37.0) vs. 17.0 (interquartile range: 8.0–30.0) years, P=0.037], lower HbA1c (64.6±20.3 vs. 72.4±18.5 mmol/mol, P=0.026), and reduced rate of hypoglycemia (23.8% vs. 52.2%, P=0.003). Age of diagnosis was positively correlated with detectable FCP level (r=0.393, P=0.020). Individuals diagnosed after 30 years of age tended to retain residual β-cell function (OR =3.016, P=0.044). We found no association between residual β-cell function and chronic diabetic complications.

Conclusions

Residual β-cell function can be found in nearly 40% of long-term patients with T1D in China and is associated with older age at diagnosis and better glucose control. The relationship between residual β-cell function and chronic diabetic complications remains to be explored.

Relationship of continuous glucose monitoring-related metrics with HbA1c and residual β-cell function in Japanese patients with type 1 diabetes

The targets for continuous glucose monitoring (CGM)-derived metrics were recently set; however, studies on CGM data over a long period with stable glycemic control are limited. We analyzed 194,279 CGM values obtained from 19 adult Japanese patients with type 1 diabetes. CGM data obtained during stable glycemic control over four months were analyzed. CGM-related metrics of different durations "within 120, 90, 60, 30, and 7 days" were calculated from baseline. Time in range (TIR; glucose 70-180 mg/dL), time above range (TAR; glucose ≥ 181 mg/dL), and average glucose levels, but not time below range (TBR; glucose ≤ 69 mg/dL), strongly correlated with glycated hemoglobin (HbA1c) values (P < 0.0001). TBR correlated with glucose coefficient of variation (CV) (P < 0.01). Fasting serum C-peptide levels negatively correlated with glucose CV (P < 0.01). HbA1c of approximately 7% corresponded to TIR of 74% and TAR of 20%. The shorter the CGM period, the weaker was the relationship between HbA1c and CGM-related metrics. TIR, TAR, and average glucose levels accurately reflected HbA1c values in Japanese patients with type 1 diabetes with stable glycemic control. Glucose CV and TBR complemented the limitation of HbA1c to detect glucose variability and hypoglycemia. Stable glycemic control with minimal hypoglycemia depended on residual β-cell function.

Circulating anti-glutamic acid decarboxylase-65 antibody titers are positively associated with the capacity of insulin secretion in acute-onset type 1 diabetes with short duration in a Japanese population

Aims/Introduction

To elucidate the relationship between titers of islet autoantibodies, the C‐X‐C motif chemokine 10 – a circulating chemokine that activates T‐helper 1 cells leading to β‐cell destruction – and β‐cell function in type 1 diabetes.

Materials and Methods

In total, 58 type 1 diabetes patients positive for glutamic decarboxylase‐65 autoantibodies (GADA)‐radioimmunoassay (mean age 54.1 years; 27 acute‐onset cases and 31 slowly progressive cases) were enrolled; serum C‐X‐C motif chemokine 10 (n = 50), zinc transporter 8 autoantibodies (n = 50) and GADA (n = 58) by an enzyme‐linked immunosorbent assay, and insulinoma‐associated antigen‐2 autoantibodies by radioimmunoassay (n = 50) were measured. The ratio of 100 × random C‐peptide (ng/mL)‐to‐plasma glucose levels (mg/dL; C‐peptide index [CPI]) was measured.

Results

The CPI significantly decreased in both groups with the progression of disease duration. GADA titers by radioimmunoassay and enzyme‐linked immunosorbent assay were strongly correlated with the CPI in acute‐onset type 1 diabetes patients with a shorter disease duration (≤10 years), but not in those with a longer duration or slowly progressive type 1 diabetes. Neither insulinoma‐associated antigen‐2 nor zinc transporter 8 autoantibodies titers were correlated with the CPI. Serum C‐X‐C motif chemokine 10 levels in both groups were significantly higher than in non‐diabetic controls, and persisted at high levels even in those with chronic duration.

Conclusions

Among islet autoantibodies, the intensity of the humoral immune response, as defined by GADA titers, reflected the degree of residual β‐cell function in acute‐onset type 1 diabetes patients with short duration. Prolonged disease activity might accelerate β‐cell impairment in both subtypes of type 1 diabetes.