Corrigendum: Normal High HbA1c a Risk Factor for Abnormal Pain Threshold in the Japanese Population.

[This corrects the article DOI: 10.3389/fendo.2019.00651.].

Normal High HbA1c a Risk Factor for Abnormal Pain Threshold in the Japanese Population.

Purpose: Small fiber dysfunction is common in subjects with diabetic polyneuropathy (DPN). It is unsettled, however, whether marginal glucose intolerance is implicated in the onset and progression of small fiber dysfunction. Herein, we explored the relationship between glycated hemoglobin levels (HbA1c) and pain sensation in the Japanese population. Methods: A population-based study of 894 individuals (352 men, 542 women; average age 53.8 ± 0.5 years) and 55 subjects with impaired fasting glucose (IFG) in the 2017 Iwaki project were enrolled in this study. Individuals with diabetes were excluded. Relationships between pain threshold for intraepidermal electrical stimulation (P-IES) and parameters associated with metabolic syndrome were examined. Results: P-IES was elevated with increasing of age in women but not in men. Average P-IES (mA) was increased in IFG subjects (n = 55, 0.20 ± 0.03) compared with normoglycemic/non-IFG individuals (n = 894, 0.15 ± 0.11) (p < 0.01). It was comparable between IFG and a group of normal high HbA1c (5.9-6.4%). Univariate linear regression analyses showed no influence of sex, triglyceride, or cholesterol on the value of P-IES. In contrast, there were significant correlations between P-IES and serum HbA1c level (ß = 0.120, p < 0.001) Adjustments for the multiple clinical measurements confirmed positive correlation of P-IES with HbA1c (ß = 0.077, p = 0.046). Conclusion: Individuals with normal high HbA1c exhibited an elevated P-IES in a healthy Japanese population which may be useful for the screening of subclinical DPN.

Worsened outcome in patients with pancreatic ductal carcinoma on long-term diabetes: association with E-cadherin1 (CDH1) promoter methylation.

Prevalence of pancreatic ductal carcinoma (PDC) is nearly twice in patients with diabetes mellitus, but the reason for this close association remains obscure. Recently promoter methylation of E-cadherin1 (CDH1) and CDKN2A genes, encoding E-cadherin and P16 respectively, are invoked in development of PDC. It is still unclear whether diabetes affects such epigenetic changes and malignant behavior in PDC. In this study, we studied whether diabetes influences the clinico-pathological profile and methylation status of CDH1 and CDKN2A genes in patients with PDC. PDC subjects were divided into 3 groups; 59 cases without diabetes (non-DM), 17 cases with short-term diabetes (short-DM)(diabetes duration 3 yrs>) and 33 cases with long-term diabetes (long-DM)(≧3 yrs). Compared to non-DM or short-DM, long-DM was associated with a higher histological grade of malignancy and a higher tumor stage. Promoter methylation of both CDH1 and CDKN2A was encountered more frequently in PDC patients with long-DM than non-DM or short DM. Cases with CDH1 promoter methylation showed reduced E-cadherin expression and worsened survival. We consider that the presence of long-DM has a negative impact on the prognosis of PDC patients which may be relevant to a high frequency of promoter methylation of CDH1.

Pancreas Atrophy and Islet Amyloid Deposition in Patients With Elderly-Onset Type 2 Diabetes.

Context: With prolonged life expectancy, we often encounter patients with elderly-onset type 2 diabetes mellitus (eT2DM). Although the clinical features of eT2DM are suggested to be different from those in patients with middle-age-onset type 2 diabetes mellitus (mT2DM), the islet pathologic features in eT2DM have not been addressed. Objective: We attempted to characterize the pancreatic pathology in eT2DM and sought its clinical implications. Materials and Methods: Pancreata from 13 young nondiabetic (age, 20 to 29 years), 27 patients with mT2DM (age, 45 to 87 years), 22 middle-age subjects without T2DM, 15 subjects with eT2DM (age, 85 to 100 years), and 30 elderly subjects without T2DM were investigated. Together with conventional microscopic observations, morphometric analysis on the islet, islet endocrine cells, and amyloid deposition was conducted on immunostained sections. Results: The estimated age of diabetes onset was 80.8 ± 1.4 years (mean ± standard error) in the eT2DM group and that of the mT2DM group was 48.3 ± 2.4 years. The pancreatic weight was nearly 50% less in the eT2DM group than in the other groups, showing duct obstruction with epithelial hyperplasia, marked acinar atrophy, fibrosis, and amyloid deposition in the islet. The islet mass was significantly reduced in the eT2DM group. The amyloid volume density correlated inversely with the ß-cell volume density but not with the body mass index in the eT2DM group. Laboratory data showed mild elevation of serum amylase in the eT2DM group, although clinical signs and symptoms of pancreatitis were not apparent. Conclusions: eT2DM is distinct from mT2DM and characterized by pancreas atrophy, ductal lesions, and amyloid deposition.

Dynamic pathology of islet endocrine cells in type 2 diabetes: ß-Cell growth, death, regeneration and their clinical implications.

Diabetes is defined as a disease of hyperglycemic metabolic disorder caused by impaired insulin action or low insulin secretion, resulting in the occurrence of vascular complications. Based on this definition, diabetes therapy has long been oriented to correct hyperglycemia against the specific complications of diabetes. This definition has posed some difficulties, however, in understanding of the pathophysiology of this complicated disease and as such in the establishment of an effective treatment. With continuing efforts to explore the structural basis for diabetes onset and methodological development of immunohistochemistry, progressive decline of ß-cells is now established as a salient feature of type 2 diabetes. Accordingly, diabetes therapy has now turned out to protect ß-cells concurrently with the correction of hyperglycemia. Together with this effort, exploration of the means to regenerate ß-cells or to supply new ß-cells by, for example, induced pluripotential stem cells, are vigorously made with the search for the mechanism of ß-cell decline in diabetes. In the present review, we describe the advances in the islet pathology in type 2 diabetes with special reference to the dynamic alterations of islet endocrine cells in the milieu of maturation, obesity, aging and ethnic differences. The effect of amyloid deposition is also discussed. We hope it will help with understanding the pathophysiology of diabetes, and suggest the future direction of diabetes treatment.

The dipeptidyl peptidase IV inhibitor vildagliptin suppresses development of neuropathy in diabetic rodents: effects on peripheral sensory nerve function, structure and molecular changes.

Incretin-related therapy was found to be beneficial for experimental diabetic neuropathy, but its mechanism is obscure. The purpose of this study is to explore the mechanism through which dipeptidyl peptidase IV inhibitor, vildagliptin (VG), influences neuropathy in diabetic rodents. To this end, non-obese type 2 diabetic Goto-Kakizaki rats (GK) and streptozotocin (STZ)-induced diabetic mice were treated with VG orally. Neuropathy was evaluated by nerve conduction velocity (NCV) in both GK and STZ-diabetic mice, whereas calcitonin-gene-related peptide expressions, neuronal cell size of dorsal root ganglion (DRG) and intraepidermal nerve fiber density were examined in GK. DRG from GK and STZ-diabetic mice served for the analyses of GLP-1 and insulin signaling. As results, VG treatment improved glucose intolerance and increased serum insulin and GLP-1 in GK accompanied by the amelioration of delayed NCV and neuronal atrophy, reduced calcitonin-gene-related peptide expressions and intraepidermal nerve fiber density. Diet restriction alone did not significantly influence these measures. Impaired GLP-1 signals such as cAMP response element binding protein, protein kinase B/Akt (PKB/Akt) and S6RP in DRG of GK were restored in VG-treated group, but the effect was equivocal in diet-treated GK. Concurrently, decreased phosphorylation of insulin receptor substrate 2 in GK was corrected by VG treatment. Consistent with the effect on GK, VG treatment improved NCV in diabetic mice without influence on hyperglycemia. DRG of VG-treated diabetic mice were characterized by correction of GLP-1 signals and insulin receptor substrate 2 phosphorylation without effects on insulin receptor ß expression. The results suggest close association of neuropathy development with impaired signaling of insulin and GLP-1 in diabetic rodents. Diabetic neurons are resistant to insulin and such insulin resistance may contribute to development of neuropathy. DPP-IV inhibitor, vildagliptin, corrected insulin resistance and improved neuropathy irrespective of blood glucose via augmented action of GLP-1.

Histological evaluation of low-intensity pulsed ultrasound on osteochondritis dissecans of the humeral capitellum.

BACKGROUND: The clinical use of low-intensity pulsed ultrasound (LIPUS) was recently evaluated in cases of osteochondritis dissecans of the humeral capitellum (elbow OCD). However, the mechanism underlying the effect of LIPUS in elbow OCD is not well understood. The aim of this study was to histopathologically evaluate the effect of LIPUS irradiation on elbow OCD. METHODS: Fifteen patients with elbow OCD were enrolled in this study. All patients were juvenile baseball players (average age, 13.1 years). LIPUS was performed under the same conditions as the fracture treatment for an average length of 15.1 days in the preoperative period in seven patients (LIPUS group). Cylindrical tissue specimens obtained at the time of surgery were stained with hematoxylin and eosin and alcian blue, and were also immunostained to detect type 1 collagen (Col-1), osteopontin (OPN), and Runx2. The state of the cartilage and subchondral bone and expression levels of Col-1, OPN, and Runx2 were evaluated with a semiquantitative grading system by a blinded pathologist. Histological and immunohistological findings in both groups were compared using Fisher's exact test. RESULTS: Both groups showed reparative tissue and cartilaginous metaplasia at the separation level near the subchondral bone; Col-1 was expressed in the reparative tissue. Furthermore, OPN and Runx2 were expressed in the interstitial cells near the separation level. The cartilage and subchondral bone findings in histological evaluations did not differ significantly between the LIPUS and control groups. The distribution of OPN expression levels in the two groups was as follows: Grade 0-LIPUS group, zero patients, and control group, five patients; Grade 1-LIPUS group and control group, two patients each; Grade 2-LIPUS group, five patients and control group, one patient; Grade 3-LIPUS group, one patient and control group, zero patients. OPN expression was significantly higher in the LIPUS group than in the control group (p = 0.04). CONCLUSION: LIPUS stimulation increased the expression levels of OPN in elbow OCD.

Islet amyloid with macrophage migration correlates with augmented ß-cell deficits in type 2 diabetic patients.

AIMS: Islet amyloid is a hallmark in type 2 diabetic subjects, but its implication in clinical features and development of islet pathology is still unclear. METHODS: From 118 autopsy cases with type 2 diabetes, 26 cases with islet amyloid deposition (DA+) were selected. Twenty diabetic subjects without obvious amyloid deposition (DA-) matched for the age and diabetes duration and 20 non-diabetic subjects (ND) served for comparison. We examined the severity of amyloid deposition and its relationships with population of endocrine cells, expression of cell damage markers or macrophage infiltration. Correlation of clinical profile with islet pathology was also sought on the subset of the investigated patients. RESULTS: ß-Cell volume density was nearly 40% less in DA+ and 20% less in DA- when compared to ND. Severity of amyloid deposition correlated with reduced volume densities of ß-cell and α-cell, and increased body mass index (BMI), but not with duration of diabetes, age or HbA1c. Amyloid-rich islets contained an increased number of macrophages mixed with ß-cells with oxidative stress-related DNA damage, characterized by γH2AX expression, and suppressed (pro)insulin mRNA expression. CONCLUSIONS: In Japanese type 2 diabetic patients, islet amyloid was more common with severe ß-cell loss and high BMI, associated with macrophage infiltration.

Age-associated changes of islet endocrine cells and the effects of body mass index in Japanese.

AIMS/INTRODUCTION: Impaired growth and premature death of ß-cells are implicated in the progression of islet pathology in type 2 diabetes. It remains unclear, however, how aging affects islet cells, or whether the islet change in diabetes is an augmented process of aging. We studied age-related changes of the islet structure in Japanese non-diabetic subjects and explored the underlying mechanism of the changes. MATERIALS AND METHODS: A total of 115 non-diabetic autopsy cases were subjected to morphometric analysis for volume densities of islets, ß- and non-ß-cells, as well as their masses. Proliferation activity identified by Ki67, and expressions of pancreatic and duodenal homeobox (PDX)-1, cell cycle inhibitor P16, and oxidative stress marker γH2AX were also examined. RESULTS: There was a gradual and marginal decline of volume densities of islets, ß- and non-ß-cells with aging, while masses of these components were increased during maturation and slowly decreased after the 40s. Islet density was high in the young, but reduced after maturation. There was only a minimal influence of increased body mass index (BMI) on the increase in ß-cell mass, but not on the other variables. Ki67 positivity and PDX-1 expressions were high in the young, but low after maturation, whereas expressions of P16 and γH2AX were elevated in the aged. CONCLUSIONS: Age-associated decline of ß-cell mass is marginal after maturation, and the reduction of ß-cell mass could be a specific process in diabetes. The impact of BMI on the islet structure is limited in Japanese with normal glucose tolerance.

Involvement of oxidative stress-induced DNA damage, endoplasmic reticulum stress, and autophagy deficits in the decline of ß-cell mass in Japanese type 2 diabetic patients.

OBJECTIVE: Deficits of ß-cells characterize the islet pathology in type 2 diabetes. It is yet to be clear how the ß-cell loss develops in type 2 diabetes. We explored the implication of oxidative stress, endoplasmic reticulum (ER)-induced stress, and autophagy deficit in the ß-cell decline in Japanese type 2 diabetic patients. RESEARCH DESIGN AND METHODS: Pancreases from recent autopsy cases of 47 type 2 diabetic and 30 nondiabetic subjects were investigated on the islet structure with morphometric analysis. Volume densities of islet (Vi), ß-cell (Vß), and α-cell (Vα) were measured. To evaluate cell damage of endocrine cells, immunohistochemical expressions of oxidative stress-related DNA damage as expressed by γH2AX, ER stress-related cell damage as CCAAT/enhancer 1 binding protein-ß (C/EBP-ß), and autophagy deficit as P62 were semiquantified, and their correlations to islet changes were sought. RESULTS: Compared with nondiabetic subjects, Vß was reduced in diabetic subjects. Contrariwise, there was an increase in Vα. There was a significant link between reduced Vß and increased HbA1c levels (P < 0.01) and a trend of inverse correlation between Vß and duration of diabetes (P = 0.06). Expressions of γH2AX, P62, and C/EBP-ß were all enhanced in diabetic islets, and reduced Vß correlated with the intensity of γH2AX expression but not with C/EBP-ß or P62 expressions. Combined expressions of γH2AX, P62, and C/EBP-ß were associated with severe reduction of Vß. CONCLUSIONS: ß-Cell deficit in type 2 diabetes was associated with increased oxidative stress and may further be augmented by autophagic deficits and ER stress.

Characterization of pancreatic islets in two selectively bred mouse lines with different susceptibilities to high-fat diet-induced glucose intolerance.

Hereditary predisposition to diet-induced type 2 diabetes has not yet been fully elucidated. We recently established 2 mouse lines with different susceptibilities (resistant and prone) to high-fat diet (HFD)-induced glucose intolerance by selective breeding (designated selectively bred diet-induced glucose intolerance-resistant [SDG-R] and -prone [SDG-P], respectively). To investigate the predisposition to HFD-induced glucose intolerance in pancreatic islets, we examined the islet morphological features and functions in these novel mouse lines. Male SDG-P and SDG-R mice were fed a HFD for 5 weeks. Before and after HFD feeding, glucose tolerance was evaluated by oral glucose tolerance test (OGTT). Morphometry and functional analyses of the pancreatic islets were also performed before and after the feeding period. Before HFD feeding, SDG-P mice showed modestly higher postchallenge blood glucose levels and lower insulin increments in OGTT than SDG-R mice. Although SDG-P mice showed greater ß cell proliferation than SDG-R mice under HFD feeding, SDG-P mice developed overt glucose intolerance, whereas SDG-R mice maintained normal glucose tolerance. Regardless of whether it was before or after HFD feeding, the isolated islets from SDG-P mice showed impaired glucose- and KCl-stimulated insulin secretion relative to those from SDG-R mice; accordingly, the expression levels of the insulin secretion-related genes in SDG-P islets were significantly lower than those in SDG-R islets. These findings suggest that the innate predispositions in pancreatic islets may determine the susceptibility to diet-induced diabetes. SDG-R and SDG-P mice may therefore be useful polygenic animal models to study the gene-environment interactions in the development of type 2 diabetes.

The effects of dipeptidyl-peptidase-IV inhibitor, vildagliptin, on the exocrine pancreas in spontaneously diabetic Goto-Kakizaki rats.

OBJECTIVES: The risk of adverse effects of dipeptidyl peptidase-4 inhibitors on the exocrine pancreas, particularly the high risk of pancreatitis, is controversial. In this study, we examined the exocrine pancreatic function and structure in spontaneously diabetic Goto-Kakizaki (GK) rats treated with a dipeptidyl peptidase-4 inhibitor. METHODS: Male GK rats and normal Wistar rats 4 weeks of age were treated with vildagliptin (VG; 30 mg/kg/d) for 18 weeks. Subsequently, exocrine pancreatic pathology and function in treated animals were compared to those in untreated animals. RESULTS: In GK rats, VG treatment suppressed elevated serum concentrations of amylase and lipase, reduced lymphocytic infiltration around ducts, around vessels, and in acinar areas, and reduced the frequency of apoptotic acinar cells and ductule formation (both of which occurred more frequently in GK rats than Wistar rats). However, VG treatment had no effect on the proliferation rate of pancreatic duct glandular cells (which was low in GK rats) and of cells in the main ducts, peripheral ducts, and acini (which was similar in all groups). CONCLUSIONS: Perturbations of exocrine pancreatic function and structure in GK rats are ameliorated by long-term VG treatment.

Immunohistochemical localization of mesenchymal stem cells in ossified human spinal ligaments.

Mesenchymal stem cells (MSCs) have been isolated from various tissues and used for elucidating the pathogenesis of numerous diseases. In our previous in vitro study, we showed the existence of MSCs in human spinal ligaments and hypothesized that these MSCs contributed to the pathogenesis of ossification of spinal ligaments. The purpose of this study was to use immunohistochemical techniques to analyze the localization of MSCs in ossified human spinal ligaments in situ. Ossified (OLF) or non-ossified ligamentum flavum (non-OLF) samples from the thoracic vertebra were obtained from patients who had undergone posterior spinal surgery. Serial sections were prepared from paraffin-embedded samples, and double immunofluorescence staining was performed using antibodies against markers for MSCs (CD73, CD90 and CD105), endothelial cells (CD31), pericytes (α-smooth muscle actin), and chondrocytes (S100). Immunolocalization of MSCs was observed in the perivascular area and collagenous matrix in spinal ligaments. Markers for MSCs and pericytes were co-expressed in the perivascular area. Compared with non-OLF, OLF had a large amount of neovascularization in the fragmented ligament matrix, and a high accumulation of MSCs around blood vessels. The prevalence of MSCs in OLF within collagenous matrix was significantly higher than that in non-OLF. Chondrocytes near the ossification front in OLF also presented expression of MSC markers. MSCs may contribute to the ectopic ossification process of OLF through endochondral ossification.

Effects of long-term treatment with the dipeptidyl peptidase-4 inhibitor vildagliptin on islet endocrine cells in non-obese type 2 diabetic Goto-Kakizaki rats.

Reduced ß cell mass is a characteristic feature of type 2 diabetes and incretin therapy is expected to prevent this condition. However, it is unknown whether dipeptidyl peptidase-4 inhibitors influence ß and α cell mass in animal models of diabetes that can be translated to humans. Therefore, we examined the long-term effects of treatment with the dipeptidyl peptidase-4 inhibitor vildagliptin on islet morphology in Goto-Kakizaki (GK) rats, a spontaneous, non-obese model of type 2 diabetes, and explored the underlying mechanisms. Four-week-old GK rats were orally administered with vildagliptin (15 mg/kg) twice daily for 18 weeks. Glucose tolerance was monitored during the study. After 18 weeks, ß and α cell morphology and the expression of molecules involved in cell proliferation and cell death were examined by immunohistochemistry and morphometric analysis. We found that vildagliptin improved glucose tolerance and insulin secretion, and suppressed hyperglucagonemia by increasing plasma active glucagon-like peptide-1 concentrations. ß cell mass was reduced in GK rats to 40% of that in Wistar rats, but was restored to 80% by vildagliptin. Vildagliptin enhanced ß and α cell proliferation, and increased the number of small neogenetic islets. Vildagliptin also reduced the number of 8-hydroxy-2'-deoxyguanosine-positive cells and forkhead box protein O1 expression, inhibited macrophage infiltration, and enhanced S6 ribosomal protein, molecule of target of rapamycin, and pancreatic duodenal homeobox 1 expression. These results indicate that starting vildagliptin treatment from an early age improved glucose tolerance and preserved islet ß cell mass in GK rats by facilitating the proliferation of islet endocrine cells.

Amelioration of acute kidney injury in lipopolysaccharide-induced systemic inflammatory response syndrome by an aldose reductase inhibitor, fidarestat.

BACKGROUND: Systemic inflammatory response syndrome is a fatal disease because of multiple organ failure. Acute kidney injury is a serious complication of systemic inflammatory response syndrome and its genesis is still unclear posing a difficulty for an effective treatment. Aldose reductase (AR) inhibitor is recently found to suppress lipopolysaccharide (LPS)-induced cardiac failure and its lethality. We studied the effects of AR inhibitor on LPS-induced acute kidney injury and its mechanism. METHODS: Mice were injected with LPS and the effects of AR inhibitor (Fidarestat 32 mg/kg) before or after LPS injection were examined for the mortality, severity of renal failure and kidney pathology. Serum concentrations of cytokines (interleukin-1ß, interleukin-6, monocyte chemotactic protein-1 and tumor necrosis factor-α) and their mRNA expressions in the lung, liver, spleen and kidney were measured. We also evaluated polyol metabolites in the kidney. RESULTS: Mortality rate within 72 hours was significantly less in LPS-injected mice treated with AR inhibitor both before (29%) and after LPS injection (40%) than untreated mice (90%). LPS-injected mice showed marked increases in blood urea nitrogen, creatinine and cytokines, and AR inhibitor treatment suppressed the changes. LPS-induced acute kidney injury was associated with vacuolar degeneration and apoptosis of renal tubular cells as well as infiltration of neutrophils and macrophages. With improvement of such pathological findings, AR inhibitor treatment suppressed the elevation of cytokine mRNA levels in multiple organs and renal sorbitol accumulation. CONCLUSION: AR inhibitor treatment ameliorated LPS-induced acute kidney injury, resulting in the lowered mortality.

Augmented reduction of islet ß-cell mass in Goto-Kakizaki rats fed high-fat diet and its suppression by pitavastatin treatment.

UNLABELLED: Aims/Introduction: High fat diet (HFD) is known to be a risk for development of type 2 diabetes. It is unclear, however, how it affects the glucose tolerance or the islet structure in type 2 diabetes. The aim of this study is: (i) to examine the effects of HFD on the islet in GK rats, non-obese type 2 diabetic model; and (ii) to explore if pitavastatin treatment influences the change. MATERIALS AND METHODS: To see the effects of HFD on islet changes in type 2 diabetes, 4-week old male GK and Wistar rats were fed HFD for 16 weeks and subjected to glucose tolerance tests and pathological studies of the islet. The effects of pitavastatin (3 mg/kg/day for 16 weeks, oral), one of the lipophilc statins, were also examined in both GK and Wistrar rats fed with or without HFD. RESULTS: The HFD induced hyperlipidemia and aggravated glucose intolerance in both GK and Wistar rats. Pitavastatin treatment did not influence the glucose tolerance in HFD-fed animals. HFD caused an increase in hepatic lipid contents in all the animals, which was partially suppressed by pitavastatin treatment. GK rats showed reduced ß-cell mass, and fibrosis and macrophage migration in the islets. HFD feeding in GK rats augmented these changes which were associated with enhanced expression of 8-hydroxydeoxyguanosine and an increase in apoptotic cells. Pitavastatin treatment improved the HFD-induced islet pathology, and pancreatic insulin contents paralleled the structural changes. CONCLUSIONS: HFD feeding worsened the islet pathology in GK rats which was suppressed by pitavastatin treatment. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00173.x, 2011).