Diabetic myonecrosis: A rare complication of long-standing diabetes mellitus

BACKGROUND

Diabetes mellitus is a rapidly growing health illness worldwide and its incidence is expected to continue rising. Various complications have been cited including retinopathy, nephropathy, peripheral artery disease and ulceration among others. However, rarer complications such as diabetic myonecrosis are limited in literature. This case report demonstrates the presentation of this complication to allow for earlier detection and treatment by providers.

CASE REPORT

This case highlights a 49-year-old man with an extensive past medical history inclusive of diabetes mellitus type 2, who presented with acute onset left thigh pain and swelling. On presentation, the patient has an HbA1c of 8 % and hyperpigmented spots were noted bilaterally on the lower extremities. Initial management was centered around infectious etiologies and management which failed to improve his symptoms. Further work-up included a negative lower extremity duplex ultrasound and a CT scan showing a hypodense lesion in the left lower extremity. Following unsuccessful drainage of the lesion to assess for a possible abscess, MRI of the lower extremities showed bilateral myositis and myonecrosis centered in the left vastus medialis.

CONCLUSION

This case report highlights a rare complication of diabetes mellitus known as diabetic myonecrosis (DMN). The gold-standard diagnostic tool is a muscle biopsy, however, sensitive imaging like MRI and clinical context are sufficient for a diagnosis. Supportive care centered around pain management remains the standard of care. While this remains as a diagnosis of exclusion, early identification may decrease the number of unnecessary treatments and should remain as a differential in patients with this presentation.

Characterizing Vascular Wall and Lumen Caliber in Eyes with Diabetic Retinopathy Based on Adaptive Optics Scanning Laser Ophthalmoscopy

(200/200) Purpose: Our aim was to evaluate structural alterations of retinal arterioles due to type 1 diabetes (T1D) and/or diabetic retinopathy (DR) under AOSLO imaging.

METHODS

Each study eye underwent mydriasis and AOSLO imaging in a single-visit study. The instrument's arrangement of four offset aperture images provided two orthogonal split-detector images and enabled isotropic analysis of the arteriolar boundaries. For each arteriole, we calculated the wall-to-lumen ratio (WLR), mean wall thickness, and luminal and external diameters.

RESULTS

In total, we enrolled 5 (20.8%) healthy control eyes and 19 eyes of patients with T1D. The DR distribution was: four (16.7%) no-DR, nine (37.5%%) mild or moderate nonproliferative DR (NPDR), and six (25%) severe NPDR or proliferative DR. Mean wall thickness increased significantly in eyes with T1D compared to healthy controls (p = 0.0006) and in eyes with more advanced DR (p = 0.0004). The WLR was significantly higher in eyes with T1D (p = 0.002) or more severe DR (p = 0.004). There was no significant relationship between T1D status or DR severity and any of the arteriolar diameters.

CONCLUSIONS

In this preliminary study, there appeared to be increases in the WLR and mean wall thickness in eyes with T1D and more severe DR than in the controls and eyes with no/less severe DR. Future studies may further elucidate the relationship between the retinal arteriolar structure and physiologic alterations in DR.

Pathogenic Mechanisms That May Link Periodontal Disease and Type 2 Diabetes Mellitus-The Role of Oxidative Stress

Given the posited role of oxidative stress in the pathogenesis of both periodontitis and type 2 diabetes mellitus (T2DM), it may also serve as a link between these highly prevalent chronic inflammatory diseases. This view is supported by an ample body of evidence indicating that the severity and progression of periodontitis is in part driven by diabetes, while periodontal infection may hinder the attainment of adequate glycemic control in diabetic patients. Thus, this review focuses on the potential synergistic interactions along the oxidative stress-inflammation pathway characterizing both conditions. Because periodontitis and T2DM share the same risk factors and compromise patients' quality of life, to develop effective strategies for combatting both conditions, their mutual influence needs to be explored.

Ageing-Related Neurodegeneration and Cognitive Decline

Neuropathological assessment was conducted on 1630 subjects, representing 5% of all the deceased that had been sent to the morgue of Uppsala University Hospital during a 15-year-long period. Among the 1630 subjects, 1610 were ≥41 years of age (range 41 to 102 years). Overall, hyperphosphorylated (HP) τ was observed in the brains of 98% of the 1610 subjects, and amyloid β-protein (Aβ) in the brains of 64%. The most common alteration observed was Alzheimer disease neuropathologic change (ADNC) (56%), followed by primary age-related tauopathy (PART) in 26% of the subjects. In 16% of the subjects, HPτ was limited to the locus coeruleus. In 14 subjects (<1%), no altered proteins were observed. In 3 subjects, only Aβ was observed, and in 17, HPτ was observed in a distribution other than that seen in ADNC/PART. The transactive DNA-binding protein 43 (TDP43) associated with limbic-predominant age-related TDP encephalopathy (LATE) was observed in 565 (35%) subjects and α-synuclein (αS) pathology, i.e., Lewy body disease (LBD) or multi system atrophy (MSA) was observed in the brains of 21% of the subjects. A total of 39% of subjects with ADNC, 59% of subjects with PART, and 81% of subjects with HPτ limited to the locus coeruleus lacked concomitant pathologies, i.e., LATE-NC or LBD-NC. Of the 293 (18% of the 1610 subjects) subjects with dementia, 81% exhibited a high or intermediate level of ADNC. In 84% of all individuals with dementia, various degrees of concomitant alterations were observed; i.e., MIXED-NC was a common cause of dementia. A high or intermediate level of PART was observed in 10 subjects with dementia (3%), i.e., tangle-predominant dementia. No subjects exhibited only vascular NC (VNC), but in 17 subjects, severe VNC might have contributed to cognitive decline. Age-related tau astrogliopathy (ARTAG) was observed in 37% of the 1610 subjects and in 53% of those with dementia.

Single-cell transcriptional profiling reveals immunomodulatory properties of stromal and epithelial cells in periodontal immune milieu with diabetes in rats

Periodontitis is the sixth major complication of diabetes. Gingiva, as an important component of periodontal tissues, serves as the first defense barrier against infectious stimuli. However, relatively little is known about cellular heterogeneity and cell-specific changes in gingiva in response to diabetes-associated periodontitis. To characterize molecular changes linking diabetes with periodontitis, we profiled single-cell transcriptome analyses of a total of 45,259 cells from rat gingiva with periodontitis under normoglycemic and diabetic condition. The single-cell profiling revealed that stromal and epithelial cells of gingiva contained inflammation-related subclusters enriched in functions of immune cell recruitment. Compared to normoglycemic condition, diabetes led to a reduction in epithelial basal cells, fibroblasts and smooth muscle cells in gingiva with periodontitis. Analysis of differentially expressed genes indicated that stromal and epithelial populations were reprogrammed towards pro-inflammatory phenotypes promoting immune cell recruitment in diabetes-related periodontitis. In aspect of immune cells, diabetes prominently enhanced neutrophil and M1 macrophage infiltration in periodontitis lesions. Cell-cell communications revealed enhanced crosstalk between stromal/epithelial cells and immune cells mediating by chemokine/chemokine receptor interplay in diabetes-associated periodontitis. Our findings deconvolved cellular heterogeneity of rat gingiva associated with periodontitis and diabetes, uncovered altered immune milieu caused by the disease, and revealed immunomodulatory functions of stromal and epithelial cells in gingival immune niche. The present study improves the understanding of the link between the diabetes and periodontitis and helps in formulating precise therapeutic strategies for diabetes-enhanced periodontitis.

Co-occurrence of Periodontitis and Diabetes-Related Complications

Periodontitis is a common finding among people with diabetes mellitus (DM) and has been cited as a DM complication. Whether and how periodontitis relates to other diabetes-related complications has yet to be explored. This study aims to examine the clustering of periodontitis with other diabetes-related complications and explore pathways linking diabetes-related complications with common risk factors. Using data from participants with DM across 3 cycles of the National Health and Nutrition Examination Survey (NHANES) (n = 2,429), we modeled direct and indirect pathways from risk factors to diabetes-related complications, a latent construct comprising periodontitis, cardiovascular diseases, proteinuria, and hypertension. Covariates included age, sex, socioeconomic status (SES), smoking, physical activity, healthy diet, alcohol consumption, hemoglobin A1c (HbA1c), dyslipidemia, and body mass index (BMI). Sensitivity analyses were performed considering participants with overweight/obesity and restricting the sample to individuals without DM. Periodontitis clustered with other diabetes complications, forming a latent construct dubbed diabetes-related complications. In NHANES III, higher HbA1c levels and BMI, older age, healthy diet, and regular physical activity were directly associated with the latent variable diabetes-related complications. In addition, a healthy diet and BMI had a total effect on diabetes-related complications. Although sex, smoking, dyslipidemia, and SES demonstrated no direct effect on diabetes-related complications in NHANES III, a direct effect was observed using NHANES 2011-2014 cycles. Sensitivity analysis considering participants with overweight/obesity and without DM showed consistent results. Periodontal tissue breakdown seems to co-occur with multiple diabetes-related complications and may therefore serve as a valuable screening tool for other well-known diabetes-related complications.

Nephroprotective Effect of Coenzyme Q10 alone and in Combination with N-acetylcysteine in Diabetic Nephropathy

Aim

Oxidative stress due to chronic hyperglycaemia is a key factor in the development and progression of various microvascular complications including diabetic nephropathy (DN) and associated renal injury. Treatment with antioxidants is one of the strategies to protect the kidney from oxidative tissue damage to improve renal physiology during DN. The investigation, therefore, was designed to assess the nephroprotective effect of coenzyme Q10 (CoQ10) and N-acetylcysteine (NAC), either alone or in combination in streptozotocin (STZ)-nicotinamide (NAD) induced diabetic nephropathy (DN) in rats.

Methods

T2DM induced by STZ (55 mg/kg, i.p.)-NAD (110 mg/kg, i.p.) in Sprague-Dawley rats (220–250 g) was confirmed by the elevated blood glucose level and glycated haemoglobin. DN was assessed by renal function tests. The diabetic rats were treated with CoQ10 (10 mg/kg, p.o.) and/or NAC (300 mg/kg, p.o.) for 8 weeks after confirmation of DN. Oxidative tissue damage due to STZ-NAD was estimated by malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT), reduced glutathione (GSH), myeloperoxidase (MPO) and nitric oxide (NO) in the renal homogenate.

Results

Data showed significant alteration in serum and urinary creatinine, total protein, albumin, serum urea, blood urea nitrogen (BUN) and uric acid in diabetic animals as compared to the control rats. CoQ10 and/or NAC effectively alleviated the disturbances in renal function. Diabetic rats showed increased MDA, decreased SOD and CAT activities and decreased GSH along with a significant increase in MPO activity and nitrite content. Treatment with the aforementioned antioxidants and their combination ameliorated the kidney damage as indicated by the reduced OS with improved renal function.

Conclusion

The investigation suggests that the chronic hyperglycaemia-induced OS leads to the development and progression of DN. The combined treatment with CoQ10 and NAC has shown a remarkable nephroprotective effect suggesting that combined antioxidant therapy with CoQ10 and NAC may be useful in the attenuation of DN.

Current molecular aspects in the development and treatment of diabetes

Diabetes mellitus (DM) leads to microvascular, macrovascular, and neurological complications. Less is understood about the mechanisms of this disease that give rise to weak bones. The many molecular mechanisms proposed to explain the damage caused by chronic hyperglycemia are organ and tissue dependent. Since all the different treatments for DM involve therapeutic activity combined with side effects and each patient represents a unique condition, there is no generalized therapy. The alterations stemming from hyperglycemia affect metabolism, osmotic pressure, oxidative stress, and inflammation. In part, hemodynamic modifications are linked to the osmotic potential of the excess of carbohydrates implicated in the disease. The change in osmotic balance increases as the disease progresses because hyperglycemia becomes chronic. The aim of the current contribution is to provide an updated overview of the molecular mechanisms that participate in the development and treatment of diabetes.

Effect of high glucose on cytokine production by human peripheral blood immune cells and type I interferon signaling in monocytes: Implications for the role of hyperglycemia in the diabetes inflammatory process and host defense against infection

The major metabolic feature of diabetes is hyperglycemia which has been linked to the diabetes inflammatory processes, and diabetes-related vulnerability to infection. In the present study, we assessed how glucose affected PBMCs in type I interferon (IFN) production and subsequent signaling. We found that the moderately elevated glucose promoted, and high glucose suppressed type I IFN production, respectively. Pre-exposure to high glucose rendered monocytes more sensitive to IFN-α stimulation with heightened signaling, whereas, instantaneous addition of high glucose did not exhibit such effect. Consistent with this finding, the mRNA levels of IFN-α-induced IRF-7 in PBMCs were positively correlated with HbA1c levels of diabetes patients. Additionally, we found that high glucose promoted the production of other proinflammatory cytokines/chemokines. This study suggests that hyperglycemia may affect the inflammatory process in diabetes via promoting proinflammatory cytokines, as well as the host defense against microbial infections through impeding type I IFN production and signaling.

Connexin channel and its role in diabetic retinopathy

Diabetic retinopathy is the leading cause of blindness in the working age population. Unfortunately, there is no cure for this devastating ocular complication. The early stage of diabetic retinopathy is characterized by the loss of various cell types in the retina, namely endothelial cells and pericytes. As the disease progresses, vascular leakage, a clinical hallmark of diabetic retinopathy, becomes evident and may eventually lead to diabetic macular edema, the most common cause of vision loss in diabetic retinopathy. Substantial evidence indicates that the disruption of connexin-mediated cellular communication plays a critical role in the pathogenesis of diabetic retinopathy. Yet, it is unclear how altered communication via connexin channel mediated cell-to-cell and cell-to-extracellular microenvironment is linked to the development of diabetic retinopathy. Recent observations suggest the possibility that connexin hemichannels may play a role in the pathogenesis of diabetic retinopathy by allowing communication between cells and the microenvironment. Interestingly, recent studies suggest that connexin channels may be involved in regulating retinal vascular permeability. These cellular events are coordinated at least in part via connexin-mediated intercellular communication and the maintenance of retinal vascular homeostasis. This review highlights the effect of high glucose and diabetic condition on connexin channels and their impact on the development of diabetic retinopathy.

Muscle changes in patients with diabetes and chronic exertional compartment syndrome before and after treatment with fasciotomy

INTRODUCTION

Muscle changes in patients with diabetes and lower leg pain due to chronic exertional compartment syndrome (CECS) were investigated before and after fasciotomy.

METHODS

The tibialis anterior muscle was analyzed with histochemical and morphological techniques in 7 patients with diabetes and CECS before fasciotomy and in 5 of them 1 year after fasciotomy. Nondiabetic patients with CECS and healthy participants served as references.

RESULTS

Before treatment, walking distance until occurrence of pain was limited (<0.2 km). Intramuscular pressure was significantly higher than in reference participants. Muscle analysis showed changes pathognomonic for neuropathy and myopathy and a restricted capillary network, with significantly more severe changes in the muscles of patients with diabetes than in the muscles of nondiabetic patients. Treatment with fasciotomy improved clinical signs, increased walking ability, and reduced muscle abnormalities, but muscle capillarization remained low.

DISCUSSION

Patients with diabetes and CECS have distinct pathological changes in affected muscles. Pressure-relieving fasciotomy triggers a regenerative response in the muscle tissue but not in the capillary bed. Muscle Nerve 57: 229-239, 2018.

The number of microvascular complications is associated with an increased risk for severity of periodontitis in type 2 diabetes patients: Results of a multicenter hospital-based cross-sectional study

Aims/Introduction

To explore the relationships between periodontitis and microvascular complications as well as glycemic control in type 2 diabetes patients.

Materials and Methods

This multicenter, hospital‐based, cross‐sectional study included 620 patients with type 2 diabetes. We compared the prevalence and severity of periodontitis between patients with ≥1 microvascular complication and those without microvascular complications. We also compared the prevalence and severity of periodontitis among patients with different degrees of glycemic control.

Results

After adjusting for confounding factors, multiple logistic regression analysis showed that the severity of periodontitis was significantly associated with the number of microvascular complications (odds ratio 1.3, 95% confidence interval 1.1–1.6), glycated hemoglobin ≥8.0% (64 mmol/mol; odds ratio 1.6; 95% confidence interval 1.1–2.3), and older age (≥50 years; odds ratio 1.7; 95% confidence interval 1.1–2.6). However, the prevalence of periodontitis was not significantly associated with the number of microvascular complications, but was associated with male sex, high glycated hemoglobin (≥8.0% [64 mmol/mol]), older age (≥40 years), longer duration of diabetes (≥15 years) and fewer teeth (≤25). Furthermore, propensity score matching for age, sex, diabetes duration and glycated hemoglobin showed that the incidence of severe periodontitis was significantly higher among patients with microvascular complications than among those without microvascular complications (P < 0.05).

Conclusions

The number of microvascular complications is a risk factor for more severe periodontitis in patients with type 2 diabetes, whereas poor glycemic control is a risk factor for increased prevalence and severity of periodontitis.

Nephroprotective effect of Paeonia emodi via inhibition of advanced glycation end products and oxidative stress in streptozotocin-nicotinamide induced diabetic nephropathy

The present study aimed to evaluate the effect of alcohol (PA) and hydroalcohol (PHA) extract of Paeonia emodi Royale roots in treatment of streptozotocin–nicotinamide induced diabetic nephropathy. Diabetes mellitus was induced in male Wistar rats by streptozotocin (65 mg/kg intraperitoneally) 15 minutes after nicotinamide (230 mg/kg, intraperitoneally) administration and diabetic nephropathy was assessed by measuring serum glucose, renal parameters (urea, uric acid, creatinine, and blood urea nitrogen level) and lipid profile. The rats were treated with different doses of extracts (100 mg/kg, 200 mg/kg, and 400 mg/kg) for 45 days. Oxidative stress was assessed by measuring tissue antioxidant enzymes level along with the formation of advanced glycation end-products (AGEs) in kidney. PA and PHA (400 mg/kg) produced significant attenuation in the serum glucose level (165.08 ± 3.353 mg/dL and 154.27 ± 2.209 mg/dL, respectively) as compared to control. Elevated renal parameters, lipid levels, tissue antioxidant enzymes and AGE formation were also restored in a dose-dependent manner. These findings suggest that by amelioration of oxidative stress and formation of AGEs, PA and PHA significantly inhibited the progression diabetic nephropathy in rats.

Assessment of the hemodynamic profile in periodontal tissues of diabetic subjects with periodontitis by optical spectroscopy

BACKGROUND AND OBJECTIVE

The influence of diabetes mellitus (DM) on the hemodynamics of periodontal tissues has not been assessed previously. The primary objective of this study was to validate optical spectroscopy as a periodontal diagnostic tool for subjects with type 2 DM and chronic periodontitis.

MATERIAL AND METHODS

Using a portable optical near-infrared spectrometer, optical spectra were obtained from healthy (n = 127), gingivitis (n = 115), and periodontitis (n = 109) sites of 65 subjects with type 2 DM and chronic periodontitis. Healthy (n = 65) sites of 15 nondiabetic subjects without periodontitis were used as controls. A modified Beer-Lambert unmixing model that incorporates a nonparametric scattering-loss function was used to determine the relative contribution of deoxygenated hemoglobin and oxygenated hemoglobin (HbO2 ) to the overall spectrum. The balance between tissue oxygen delivery and oxygen utilization in periodontal tissues was assessed.

RESULTS

In diabetic subjects, tissue oxygen saturation and HbO2 concentration were significantly decreased in the periodontitis sites (p < 0.01) compared with the healthy and gingivitis sites. Furthermore, tissue oxygenation in healthy sites of control subjects was significantly higher than that in sites of diabetic subjects (p < 0.01).

CONCLUSION

In summary, the results of this study suggest that optical spectroscopy can monitor the hemodynamic profile in diabetic subjects with chronic periodontitis. Furthermore, healthy sites of diabetic subjects presented lower tissue oxygenation than did those of nondiabetic subjects.

FOXO1, TGF-β regulation and wound healing

Re-epithelialization is a complex process that involves migration and proliferation of keratinocytes, in addition to the production of cytokines and growth factors that affect other cells. The induction of transcription factors during these processes is crucial for successful wound healing. The transcription factor forkhead boxO-1 (FOXO1) has recently been found to be an important regulator of wound healing. In particular, FOXO1 has significant effects through regulation of transforming growth factor-beta (TGF-β) expression and protecting keratinocytes from oxidative stress. In the absence of FOXO1, there is increased oxidative damage, reduced TGF-β1 expression, reduced migration and proliferation of keratinocytes and increased keratinocytes apoptosis leading to impaired re-epithelialization of wounds.

Relationship between serum transforming growth factor β 1 concentrations and the duration of type 1 diabetes mellitus in children and adolescents

The aim of this study was to evaluate the relationship between serum transforming growth factor β 1 (TGF- β 1) concentrations and the duration of type 1 diabetes mellitus (T1DM) in children and adolescents. One hundred and sixteen patients with T1DM and 19 healthy controls were examined. Serum TGF- β 1 concentrations were measured using the cytometric bead array (CBA). A positive association between the time of diabetes duration and higher serum TGF- β 1 concentrations was observed. Similarly, the prevalence of microvascular complications, such as retinopathy and nephropathy, increased with the duration of diabetes. Logistic regression analysis showed that serum TGF- β 1 concentrations and the duration of the disease are independent risk factors of microangiopathy development. Higher serum TGF- β 1 concentrations were associated with a significant risk of microangiopathy development after 10 years of T1DM duration. In the successive years of the disease, the effect was even stronger. The results of our study indicate that serum TGF- β 1 concentrations are one of the factors that may have an impact on the progression of vascular complications in children and adolescents with T1DM.

Plumbagin ameliorates diabetic nephropathy via interruption of pathways that include NOX4 signalling

NADPH oxidase 4 (Nox4) is reported to be the major source of reactive oxygen species (ROS) in the kidneys during the early stages of diabetic nephropathy. It has been shown to mediate TGFβ1-induced differentiation of cardiac fibroblasts into myofibroblasts. Despite TGFβ1 being recognised as a mediator of renal fibrosis and functional decline role in diabetic nephropathy, the renal interaction between Nox 4 and TGFβ1 is not well characterised. The aim of this study was to investigate the role of Nox4 inhibition on TGFβ1-induced fibrotic responses in proximal tubular cells and in a mouse model of diabetic nephropathy. Immortalised human proximal tubular cells (HK2) were incubated with TGFβ1 ± plumbagin (an inhibitor of Nox4) or specific Nox4 siRNA. Collagen IV and fibronectin mRNA and protein expression were measured. Streptozotocin (STZ) induced diabetic C57BL/6J mice were administered plumbagin (2 mg/kg/day) or vehicle (DMSO; 50 µl/mouse) for 24 weeks. Metabolic, physiological and histological markers of nephropathy were determined. TGFβ1 increased Nox4 mRNA expression and plumbagin and Nox4 siRNA significantly inhibited TGF-β1 induced fibronectin and collagen IV expression in human HK2 cells. STZ-induced diabetic C57BL/6J mice developed physiological features of diabetic nephropathy at 24 weeks, which were reversed with concomitant plumbagin treatment. Histologically, plumbagin ameliorated diabetes induced upregulation of extracellular matrix protein expression compared to control. This study demonstrates that plumbagin ameliorates the development of diabetic nephropathy through pathways that include Nox4 signalling.

Occurrence of red complex microorganisms and Aggregatibacter actinomycetemcomitans in patients with diabetes

AIM

The aim of the present study was to analyze the occurrence of Porphyromonas gingivalis (P. gingivalis), Tannerella forsythia (T. forsythia), Treponema denticola (T. denticola), and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) in patients with diabetes.

METHODS

Periodontal and diabetic parameters and subgingival biofilm samples were obtained from 60 patients with diabetes and 62 patients without diabetes. By using polymerase chain reaction, the prevalence of red complex microorganisms (P. gingivalis, T. forsythia, and T. denticola) and A. actinomycetemcomitans were determined. Descriptive and non-parametric statistical analyses between groups were performed (Kruskal-Wallis, Mann-Whitney U-test, and Fisher's exact test).

RESULTS

Patients with diabetes presented significantly higher periodontal attachment loss levels compared to patients without diabetes. Red complex microorganisms were detected in lower frequencies in patients with diabetes. The detection of A. actinomycetemcomitans was higher in patients with diabetes and periodontitis compared to systemically-healthy patients without periodontitis (P < 0.05). P. gingivalis was associated with periodontitis in non-diabetic patients (P < 0.05), whereas A. actinomycetemcomitans was associated with periodontitis in diabetic patients (P < 0.05).

CONCLUSIONS

The findings of the present study indicate that there might be differences in the subgingival microbiota between diabetic and non-diabetic patients. In addition, P. gingivalis and A. actinomycetemcomitans were associated with periodontitis in patients without diabetes and patients with diabetes, respectively.

Oleanolic acid prevents progression of streptozotocin induced diabetic nephropathy and protects renal microstructures in Sprague Dawley rats

Objective:

To study the effect of oleanolic acid (OA) on streptozotocin induced diabetic nephropathy in Sprague Dawley rats.

Materials and Methods:

Four weeks after intra-peritoneal injection of streptozotocin (STZ; 55 mg/kg), the rats with proteinuria were grouped as: Control (non-diabetic, treated orally with vehicle), diabetic control (treated orally with vehicle) and three diabetic groups receiving 20, 40 and 60 mg/kg/day oral doses of OA. At the end of 8 weeks, urine and serum samples from the rats were processed for determination of creatinine, BUN and GFR. The kidney samples were processed for determination of weight changes, oxidative stress related parameters like catalase, superoxide dismutase and reduced glutathione levels. A part of one kidney from each rat was used for transmission electron microscopy (TEM).

Result:

As evident in TEM, OA inhibited the nephropathy induced alterations in podocyte integrity, basement membrane thickness and spacing between the podocytes at 60 mg/kg dose. It increased GFR and reduced oxidative stress in the kidneys in a dose dependent manner. These findings conclusively demonstrate the efficacy of OA in diabetic nephropathy. Significant decrease in the oxidative stress in kidneys indicates the role of anti-oxidant mechanisms in the effects of OA. However, OA is known to act through multiple mechanisms like inhibition of the generation of advanced glycation end products and improving the insulin secretion. These mechanisms might have contributed to its efficacy.

Conclusion:

These results conclusively demonstrate the efficacy of OA in diabetic nephropathy through its possible antioxidant activity.

High glucose-induced downregulation of connexin 30.2 promotes retinal vascular lesions: implications for diabetic retinopathy

PURPOSE

To investigate whether high glucose (HG) alters expression of connexin 30.2 (Cx30.2) and influences gap junction intercellular communication (GJIC) in retinal endothelial cells and promotes vascular lesions characteristic of diabetic retinopathy (DR).

METHODS

Western blot analysis and immunostaining were performed to determine Cx30.2 protein expression and localization in rat retinal endothelial cells (RRECs) grown in normal (N; 5 mM) or HG (30 mM) medium for 7 days. Concurrently, GJIC was assessed in cells grown in N or HG medium and in cells transfected with Cx30.2 siRNA. Similarly, retinal Cx30.2 expression was assessed in nondiabetic and diabetic rats. Additionally, the effect of reduced Cx30.2 on development of acellular capillaries (ACs) and pericyte loss (PL) was studied in retinas of Cx30.2 knockout mice.

RESULTS

Cx30.2 was identified in RRECs in vitro and in vascular cells of retinal capillaries. RRECs grown in HG exhibited significantly reduced Cx30.2 protein levels consistent with decreased Cx30.2 immunostaining compared with those grown in N medium. Cells grown in HG and cells transfected with Cx30.2 siRNA exhibited significantly diminished dye transfer compared with N or nontransfected cells. Importantly, Cx30.2 protein level and immunostaining were decreased in diabetic retinas compared with nondiabetic retinas. Retinal capillaries of Cx30.2 knockout mice exhibited increased numbers of ACs and PL compared with those of wild-type mice.

CONCLUSIONS

These results indicate that HG- or diabetes-induced downregulation of Cx30.2 expression and decrease in GJIC activity play a critical role in the development of retinal vascular lesions in early DR.

Effect of glycemic control on periodontitis in type 2 diabetic patients with periodontal disease

AIMS/INTRODUCTION

Diabetes mellitus and periodontitis are closely related. A huge number of reports has addressed the effect of periodontal intervention therapy on glycemic control, but no reports have addressed the effect of glycemic intervention therapy on periodontal disease in type 2 diabetic patients. The aim of this study was to examine the effect of improved glycemic control by glycemic intervention therapy on periodontitis in type 2 diabetic patients.

MATERIALS AND METHODS

A total of 35 patients underwent intervention therapy to improve glycemic control without periodontal treatment. Glycohemoglobin (HbA_1c), high-sensitivity C-reactive protein (hs-CRP), bleeding on probing (BOP), probing pocket depth (PPD) and intraoral community periodontal index (CPI) codes of the World health Organization (WHO) were examined at baseline, and 2 and 6 months after the intervention therapy to improve glycemic control.

RESULTS

After the improvement of glycemic control, BOP lesions improved, but deep PPD lesions and WHO CPI codes did not improve. Subanalyses showed that effective glycemic control (average HbA_1c reduction 1.8%) improved BOP lesions, but did not affect deep PPD lesions and WHO CPI codes. In addition, high BOP lesions at baseline responded more effectively to glycemic intervention. Further analysis of CPI codes in all individual periodontal sites independent of WHO CPI codes in 35 patients showed that only gingival inflammation without a deep periodontal pocket improved after glycemic intervention.

CONCLUSIONS

Effective glycemic control improves BOP lesions in type 2 diabetic patients with periodontitis through ameliorating inflammation at the gingival sites of periodontal tissue. This trial was registered with the University Hospital Medical Information Network (no. UMIN000007670).

Gut region-specific diabetic damage to the capillary endothelium adjacent to the myenteric plexus

OBJECTIVE

Damage in the capillaries supplying the MP has been proposed as a critical factor in the development of diabetic enteric neuropathy. We therefore investigated connections between STZ-induced diabetes and the BM morphology, the size of caveolar compartments, the width of TJs, the transport of albumin, and the quantitative features of Cav-1 and eNOS expression in these microvessels.

METHODS

Gut segments from diabetic rats were compared with those from insulin-treated diabetics and those from controls. The effects of diabetes on the BM, the caveolar compartments, and the TJs were evaluated morphometrically. The quantitative features of the albumin transport were investigated by postembedding immunohistochemistry. The diabetes-related changes in Cav-1 and eNOS expression were assessed by postembedding immunohistochemistry and molecular method.

RESULTS

Thickening of the BM, enlargement of the caveolar compartments, opening of the junctions, enhanced transport of albumin, and overexpression of Cav-1 and eNOS were documented in diabetic animals. Insulin replacement in certain gut segments prevented the development of these alterations.

CONCLUSIONS

These data provide morphological, functional, and molecular evidence that the endothelial cells in capillaries adjacent to the MP is a target of diabetic damage in a regional manner.

Preventive effects of North American ginseng (Panax quinquefolium) on diabetic nephropathy

PURPOSE

Ginseng has been used as an herbal medicine and nutritional supplement in East Asia for thousands of years and gained popularity in the west because of its various pharmacological properties. Panax ginseng (Asian ginseng) and Panax quinquefolium (North American ginseng) both are reported to possess antihyperglycemic properties. The aim of the present study is to evaluate the preventive effects of North American ginseng on diabetic nephropathy (DN) and the underlying mechanisms of such effects.

METHODS

Models of both type 1 (C57BL/6 mice with STZ-induced diabetes) and type 2 diabetes (db/db mice) and age- and sex-matched controls were examined. Alcoholic ginseng root (200mg/kgbodywt, daily oral gavage) extract was administered to the diabetic mice (type 1 and type 2) for two or four months in order to evaluate its effects on DN.

RESULTS

Dysmetabolic state in the diabetic mice was significantly improved by ginseng treatment. In the kidneys of diabetic animals, ginseng significantly prevented oxidative stress and reduced the NF-κB (p65) levels. Diabetes-induced up-regulations of ECM proteins and vasoactive factors in the kidneys were significantly diminished by ginseng administration. Furthermore, albuminuria and mesangial expansion in the diabetic mice were prevented by ginseng therapy.

CONCLUSION

North American ginseng has preventive effects on DN and it works through a combination of mechanisms such as antihyperglycemic and antioxidant activities.

Connexins and diabetes

Cell-to-cell interactions via gap junctional communication and connexon hemichannels are involved in the pathogenesis of diabetes. Gap junctions are highly specialized transmembrane structures that are formed by connexon hemichannels, which are further assembled from proteins called “connexins.” In this paper, we discuss current knowledge about connexins in diabetes. We also discuss mechanisms of connexin influence and the role of individual connexins in various tissues and how these are affected in diabetes. Connexins may be a future target by both genetic and pharmacological approaches to develop treatments for the treatment of diabetes and its complications.

Noninvasive measurement of plasma glucose from exhaled breath in healthy and type 1 diabetic subjects

Effective management of diabetes mellitus, affecting tens of millions of patients, requires frequent assessment of plasma glucose. Patient compliance for sufficient testing is often reduced by the unpleasantness of current methodologies, which require blood samples and often cause pain and skin callusing. We propose that the analysis of volatile organic compounds (VOCs) in exhaled breath can be used as a novel, alternative, noninvasive means to monitor glycemia in these patients. Seventeen healthy (9 females and 8 males, 28.0 ± 1.0 yr) and eight type 1 diabetic (T1DM) volunteers (5 females and 3 males, 25.8 ± 1.7 yr) were enrolled in a 240-min triphasic intravenous dextrose infusion protocol (baseline, hyperglycemia, euglycemia-hyperinsulinemia). In T1DM patients, insulin was also administered (using differing protocols on 2 repeated visits to separate the effects of insulinemia on breath composition). Exhaled breath and room air samples were collected at 12 time points, and concentrations of ~100 VOCs were determined by gas chromatography and matched with direct plasma glucose measurements. Standard least squares regression was used on several subsets of exhaled gases to generate multilinear models to predict plasma glucose for each subject. Plasma glucose estimates based on two groups of four gases each (cluster A: acetone, methyl nitrate, ethanol, and ethyl benzene; cluster B: 2-pentyl nitrate, propane, methanol, and acetone) displayed very strong correlations with glucose concentrations (0.883 and 0.869 for clusters A and B, respectively) across nearly 300 measurements. Our study demonstrates the feasibility to accurately predict glycemia through exhaled breath analysis over a broad range of clinically relevant concentrations in both healthy and T1DM subjects.

GSK-3β/CREB axis mediates IGF-1-induced ECM/adhesion molecule expression, cell cycle progression and monolayer permeability in retinal capillary endothelial cells: Implications for diabetic retinopathy

Various growth factors and cytokines are implicated in endothelial dysfunction and blood-retinal barrier (BRB) breakdown in early diabetic retinopathy (DR). However, cellular and molecular mechanisms that may underlie the pathology of DR are not fully understood yet. We therefore examined the effect of insulin-like growth factor (IGF)-1 on ECM/adhesion molecule expression, cell cycle regulation and monolayer permeability in an endothelial cell line (TR-iBRB2). We investigate whether the action of IGF-1 (1) involves glycogen synthase kinase 3beta (GSK-3β) and cAMP responsive transcription factor (CREB) and (2) alters ECM/adhesion molecule gene expression. Treatment of TR-iBRB2 cell with IGF-1 (100ng/ml for 0-24h) increases phosphorylation of (i) Akt Thr308, and its substrates including GSK-3β at Ser9, which inactivates its kinase function, and (ii) CREB at Ser133 (activation). These phosphorylations correlate positively with enhanced expression of CREB targets such as ECM protein fibronectin and cell cycle progression factor cyclin D1. However, stable transfection of a mutant GSK3β(S9A) or a dominant negative K-CREB in TR-iBRB2 prevents IGF-1-induced fibronectin and cyclin D1 expression. Furthermore, IGF-1 reduces the level of intercellular adherence molecule VE-cadherin and increases monolayer permeability in TR-iBRB2 cells when measured by FITC-dextran leakage. The effect of IGF-1 on VE-cadherin and membrane permeability is absent in TR-iBRB2 cells expressing the GSK-3β(S9A). Similarly, K-CREB reverses IGF-1 down-regulation of VE-cadherin and up-regulation of fibronectin. These results indicate that GSK-3β/CREB axis alters ECM/adhesion molecule expression and cell cycle progression in retinal endothelial cells, and may potentially contribute to endothelial dysfunction and BRB leakage in DR.

The mechanism of protracted wound healing on oral mucosa in diabetes. Review

Diabetic patients increase their body's susceptibility to infection and diabetes is a risk factor for periodontal diseases and oral infection. Although many studies showed the mechanism of impaired wound healing in diabetes, there are still arguments to shed light on what kind of factors, including local and systemic factors are involved in the protracted wound healing. This review article summarizes reports on the wound healing in diabetes and discusses the mechanism of the protracted wound healing of the oral mucosa in diabetes. Delayed vascularization, reduction in blood flow, decline in innate immunity, decreases in growth factor production, and psychological stresses may be involved in the protracted wound healing of the oral mucosa in diabetics.