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Attia MS, Ayman F, Attia MS, Yahya G, Zahra MH, Khalil MMI, Diab AAA. Mitigating diabetes-related complications: Empowering metformin with cholecalciferol and taurine supplementation in type 2 diabetic rats. World J Diabetes 2024; 15:1778-1792. [PMID: 39192867 PMCID: PMC11346095 DOI: 10.4239/wjd.v15.i8.1778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 06/30/2024] [Accepted: 07/17/2024] [Indexed: 07/25/2024] Open
Abstract
BACKGROUND Type 2 diabetes is one of the most prevalent chronic diseases worldwide, significantly impacting patients' quality of life. Current treatment options like metformin (MET) effectively counteract hyperglycemia but fail to alleviate diabetes-associated complications such as retinopathy, neuropathy, nephropathy, hepatopathy, and cardiovascular diseases. AIM To propose the supplementation of cholecalciferol (CHO) and taurine (TAU) to enhance MET efficacy in controlling diabetes while minimizing the risk of associated complications. METHODS The study involved sixty rats, including ten non-diabetic control rats and fifty experimental rats with type 2 diabetes induced by streptozotocin. The experimental rats were further subdivided into positive control and treatment subgroups. The four treatment groups were randomly allocated to a single MET treatment or MET combined with supplements either CHO, TAU, or both. RESULTS Diabetic rats exhibited elevated levels of glucose, insulin, Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), glycated hemoglobin%, lipid markers, aspartate aminotransferase, and malondialdehyde, along with reduced levels of antioxidant enzymes (catalase and superoxide dismutase). The administration of CHO and TAU supplements alongside MET in diabetic rats led to a noticeable recovery of islet mass. The antioxidative, anti-inflammatory, and anti-apoptotic properties of the proposed combination therapy significantly ameliorated the aforementioned abnormalities. CONCLUSION The supplementation of CHO and TAU with MET showed the potential to significantly improve metabolic parameters and protect against diabetic complications through its antioxidative, anti-inflammatory, and anti-apoptotic effects.
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Affiliation(s)
- Mai S Attia
- Department of Zoology, Faculty of Science, Zagazig 44519, Egypt
| | - Fadwa Ayman
- Department of Zoology, Faculty of Science, Zagazig 44519, Egypt
| | - Mohamed S Attia
- Department of Pharmaceutics, Faculty of Pharmacy, Zagazig 44519, Egypt
| | - Galal Yahya
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Mansour H Zahra
- Department of Zoology, Faculty of Science, Zagazig 44519, Egypt
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Cheng Y, Chen Y, Li K, Liu S, Pang C, Gao L, Xie J, Wenjing LV, Yu H, Deng B. How inflammation dictates diabetic peripheral neuropathy: An enlightening review. CNS Neurosci Ther 2024; 30:e14477. [PMID: 37795833 PMCID: PMC11017439 DOI: 10.1111/cns.14477] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/28/2023] [Accepted: 09/08/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND Diabetic peripheral neuropathy (DPN) constitutes a debilitating complication associated with diabetes. Although, the past decade has seen rapid developments in understanding the complex etiology of DPN, there are no approved therapies that can halt the development of DPN, or target the damaged nerve. Therefore, clarifying the pathogenesis of DPN and finding effective treatment are the crucial issues for the clinical management of DPN. AIMS This review is aiming to summary the current knowledge on the pathogenesis of DPN, especially the mechanism and application of inflammatory response. METHODS We systematically summarized the latest studies on the pathogenesis and therapeutic strategies of diabetic neuropathy in PubMed. RESULTS In this seminal review, the underappreciated role of immune activation in the progression of DPN is scrutinized. Novel insights into the inflammatory regulatory mechanisms of DPN have been unearthed, illuminating potential therapeutic strategies of notable clinical significance. Additionally, a nuanced examination of DPN's complex etiology, including aberrations in glycemic control and insulin signaling pathways, is presented. Crucially, an emphasis has been placed on translating these novel understandings into tangible clinical interventions to ameliorate patient outcomes. CONCLUSIONS This review is distinguished by synthesizing cutting-edge mechanisms linking inflammation to DPN and identifying innovative, inflammation-targeted therapeutic approaches.
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Affiliation(s)
- Yifan Cheng
- Center for Rehabilitation Medicine, Department of Neurology, Zhejiang Provincial People's HospitalAffiliated People's Hospital, Hangzhou Medical CollegeHangzhouChina
| | - Yinuo Chen
- Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang ProvinceChina
- First School of Clinical MedicineWenzhou Medical UniversityWenzhouZhejiang ProvinceChina
| | - Kezheng Li
- Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang ProvinceChina
- First School of Clinical MedicineWenzhou Medical UniversityWenzhouZhejiang ProvinceChina
| | - Shuwei Liu
- First School of Clinical MedicineWenzhou Medical UniversityWenzhouZhejiang ProvinceChina
| | - Chunyang Pang
- Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang ProvinceChina
| | - Lingfei Gao
- Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang ProvinceChina
| | - Jiali Xie
- Department of Neurology, Shanghai East HospitalTongji UniversityShanghaiP.R. China
| | - L. V. Wenjing
- Department of GeriatricsThe Affiliated Hospital of Qingdao UniversityQingdaoShandong ProvinceChina
| | - Huan Yu
- Department of PediatricsSecond Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Binbin Deng
- Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang ProvinceChina
- First School of Clinical MedicineWenzhou Medical UniversityWenzhouZhejiang ProvinceChina
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Contreras CM, Gutiérrez-García AG. Insulin and fluoxetine produce opposite actions on lateral septal nucleus-infralimbic region connection responsivity. Behav Brain Res 2023; 437:114146. [PMID: 36202146 DOI: 10.1016/j.bbr.2022.114146] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 09/28/2022] [Accepted: 10/02/2022] [Indexed: 11/07/2022]
Abstract
Some diabetes patients develop depression, the main treatment for which is antidepressants. Pharmacological interactions between insulin and antidepressants (e.g., fluoxetine) are controversial in the literature. Some authors reported hypoglycemic actions of fluoxetine, whereas others reported antidepressant-like actions. In healthy rats, insulin produces an antidespair-like action in rats through an increase in locomotor and exploratory activity, but differences in actions of insulin and fluoxetine on neuronal activity are unknown. The present study evaluated Wistar healthy rats that were treated with saline, insulin, fluoxetine, or fluoxetine + insulin for 3 days (short-term) or 21 days (long-term). The model consisted of electrical stimulation of the lateral septal nucleus (LSN) while we performed single-unit extracellular response recordings in the prelimbic cortex (PL) and infralimbic cortex (IL) subregions of the medial prefrontal cortex (mPFC). Stimulation of the LSN produced an initial brief excitatory paucisynaptic response and then a long-lasting inhibitory afterdischarge in the PL and IL. Treatment with saline and fluoxetine, but not insulin, minimally affected the paucisynaptic response. Differences were found in LSN-IL responsivity. The inhibitory afterdischarge was clearly enhanced in the long-term fluoxetine group but not by insulin alone or fluoxetine + insulin. These findings suggest that insulin produces some actions that are opposite to fluoxetine on LSN-mPFC connection responsivity, with no synergistic actions between the actions of insulin and fluoxetine.
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Affiliation(s)
- Carlos M Contreras
- Unidad Periférica del Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Xalapa, Veracruz 91190, Mexico.
| | - Ana G Gutiérrez-García
- Laboratorio de Neurofarmacología, Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Veracruz 91190, Mexico
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Association of Non-Dipping Blood Pressure Patterns with Diabetic Peripheral Neuropathy: A Cross-Sectional Study among a Population with Diabetes in Greece. Nutrients 2022; 15:nu15010072. [PMID: 36615728 PMCID: PMC9824387 DOI: 10.3390/nu15010072] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/11/2022] [Accepted: 12/15/2022] [Indexed: 12/28/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN) is present in 20-50% of cases with diabetes. The pathophysiology of DPN is not yet clear regarding hypertension (HTN). The aim of this study was to assess the association between the stages of DPN and HTN in a Greek population with diabetes. We examined 102 adults for diabetic neuropathy (DPN) from November 2020 to December 2021, using the Toronto Clinical Neuropathy Scale System (TCNSS) to categorize them into two groups (no/mild DPN versus medium/severe DPN). Ambulatory blood pressure monitoring was performed to evaluate their hypertensive status. Univariate and multivariate logistic regression analyses were performed to assess the association between the stage of DPN and HTN. The multivariate analysis, considering sex, age, and dipping status, did not show statistically significant associations between stages of HTN and DPN. However, in contrast to dippers, non-dippers had an almost four-times higher risk of developing medium-to-severe DPN (odds ratio (OR) 3.93; 95% confidence interval (CI) [1.33-11.64]); females, in contrast to males, had a 65% lower risk of developing moderate/severe DPN (OR 0.35; 95%CI [0.14-0.92]). In conclusion, our findings showed no statistically significant associations between DPN and HTN; however, dipping status, hyperglycemia, and female sex were shown to play a role in the pathophysiology of DPN.
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Shida K, Ohsawa M, Takahashi S, Ota H, Tamura T, Kusama N, Nakasone M, Yamazaki H, Sobue K. Peripheral neuropathy in the pre-diabetic state of the type 2 diabetes mouse model (TSOD mice) involves TRPV1 expression in dorsal root ganglions. IBRO Neurosci Rep 2022; 12:163-169. [PMID: 35199097 PMCID: PMC8850332 DOI: 10.1016/j.ibneur.2022.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 01/08/2022] [Accepted: 02/04/2022] [Indexed: 12/31/2022] Open
Abstract
Peripheral neuropathy, which is a complication of diabetes mellitus (DM), is thought to occur in the pre-DM state, being known as impaired glucose tolerance (IGT) neuropathy, although its pathogenesis is unknown. Since it is reversible, an effective treatment at the pre-DM stage could stop the progression of peripheral neuropathy and improve patients’ quality of life and reduce medical costs. We investigated the hypersensitivity to mechanical and thermal stimuli during the pre-DM state in Tsumura Suzuki Obese Diabetes (TSOD) mice, a type 2 DM mouse model. The expression pattern of the Transient Receptor Potential Vanilloid 1 (TRPV1)-positive cells in the dorsal root ganglia (DRG) was examined in TSOD mice, which showed a pre-DM state at 5–12 weeks of age and decreased mechanical and thermal nociceptive thresholds. Additionally, the size of TRPV1-positive cells in TSOD mice increased compared with that in non-diabetic controls (Tsumura Suzuki Non-Obesity; TSNO). Furthermore, the expression of TRPV1 on myelinated nerve fibers (neurofilament heavy-positive cells) had significantly increased. Thus, TSOD mice in the pre-DM state at 5–12 weeks of age could be a useful animal model of IGT neuropathy. We also hypothesized that the development of IGT neuropathy may involve a switch in TRPV1 expression from small, unmyelinated neurons to large, myelinated neurons in the DRG. The mechanism of peripheral neuropathy was investigated in insulin resistance state. Tsumura Suzuki Obese Diabetes (TSOD) mice showed a pre-diabetic state. TSOD mice showed mechanical and thermal hypersensitivity in a pre-diabetic state. The TRPV1 expression shifted to larger dorsal root ganglia (DRG) cells in TSOD mice. TRPV1 expression in myelinated neurons of the DRG was involved in neuropathy.
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Affiliation(s)
- Kyoko Shida
- Department of Anesthesiology and Intensive Care Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
- Correspondence to: Department of Anesthesiology and Intensive Care Medicine, Nagoya City University Graduate School of Medical Sciences, 467–8601 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Japan.
| | - Masahiro Ohsawa
- Laboratory of CNS Pharmacology, Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Satoru Takahashi
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Haruko Ota
- Department of Anesthesiology and Intensive Care Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Tetsuya Tamura
- Department of Anesthesiology and Intensive Care Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Nobuyoshi Kusama
- Department of Anesthesiology and Intensive Care Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Mina Nakasone
- Laboratory of CNS Pharmacology, Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Hisaaki Yamazaki
- Laboratory of CNS Pharmacology, Nagoya City University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Kazuya Sobue
- Department of Anesthesiology and Intensive Care Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Lee KA, Park TS, Jin HY. Non-glucose risk factors in the pathogenesis of diabetic peripheral neuropathy. Endocrine 2020; 70:465-478. [PMID: 32895875 DOI: 10.1007/s12020-020-02473-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 08/23/2020] [Indexed: 11/29/2022]
Abstract
In this review, we consider the diverse risk factors in diabetes patients beyond hyperglycemia that are being recognized as contributors to diabetic peripheral neuropathy (DPN). Interest in such alternative mechanisms has been encouraged by the recognition that neuropathy occurs in subjects with metabolic syndrome and pre-diabetes and by the reporting of several large clinical studies that failed to show reduced prevalence of neuropathy after intensive glucose control in patients with type 2 diabetes. Animal models of obesity, dyslipidemia, hypertension, and other disorders common to both pre-diabetes and diabetes have been used to highlight a number of plausible pathogenic mechanisms that may either damage the nerve independent of hyperglycemia or augment the toxic potential of hyperglycemia. While pathogenic mechanisms stemming from hyperglycemia are likely to be significant contributors to DPN, future therapeutic strategies will require a more nuanced approach that considers a range of concurrent insults derived from the complex pathophysiology of diabetes beyond direct hyperglycemia.
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Affiliation(s)
- Kyung Ae Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Research Institute of Clinical Medicine of Jeonbuk National University-Jeonbuk National University Hospital, Jeonbuk National University, Medical School, Jeonju, South Korea
| | - Tae Sun Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Research Institute of Clinical Medicine of Jeonbuk National University-Jeonbuk National University Hospital, Jeonbuk National University, Medical School, Jeonju, South Korea
| | - Heung Yong Jin
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Research Institute of Clinical Medicine of Jeonbuk National University-Jeonbuk National University Hospital, Jeonbuk National University, Medical School, Jeonju, South Korea.
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Fajrin FA, Nugroho AE, Nurrochmad A, Susilowati R. Ginger extract and its compound, 6-shogaol, attenuates painful diabetic neuropathy in mice via reducing TRPV1 and NMDAR2B expressions in the spinal cord. JOURNAL OF ETHNOPHARMACOLOGY 2020; 249:112396. [PMID: 31743763 DOI: 10.1016/j.jep.2019.112396] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 10/21/2019] [Accepted: 11/12/2019] [Indexed: 06/10/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE In silico data revealed that the active compound of ginger (Zingiber officinale Roscoe), 6-shogaol, has strong affinity toward transient receptor potential vanilloid-1 (TRPV-1). TRPV-1 is expressed in nervous tissue and pancreatic β-cells. Prolonged induction of TRPV-1 is related to the expression of N-methyl-D-aspartate receptor subunit 2B (NMDAR2B). However, there are no data on TRPV-1 and NMDAR2B expressions in nervous tissue after 6-shogaol or ginger extract treatment nor pancreatic islet morphology and insulin expression in mice model of painful diabetic neuropathy (PDN). AIM OF THE STUDY This study aimed to investigate the mechanism of action of ginger extract and its compound, 6-shogaol, on pancreatic islets as well as on expressions of TRPV-1 and NMDAR2B in the spinal cord of streptozotocin (STZ)-induced mice model of PDN. MATERIALS AND METHODS Sixty-four 5-6 weeks old male-Balb/C mice were induced with 110 mg/kgBW STZ i.p., while eight mice were used as control group. Mice with blood glucose level ≥200 mg/d, that suffered hyperalgesia and allodynia were classified as PDN mice. Hot plate and von Frey filament tests were performed once a week until termination. At day 28 after considered as PDN, ginger extracts, 6-shogaol or gabapentin as control treatment were given once daily for 21 days until day 49, except for the diabetic control group. Upon termination, mice' pancreas were fixed, processed as paraffin sections and stained with hematoxylin eosin. Total volume of pancreatic islets was estimated using Cavalieri methods. Immunohistochemistry on pancreatic sections were performed to observe insulin expression. mRNA was extracted from lumbar segments of the spinal cord, followed by cDNA preparation and quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) to measure the expressions of TRPV1 and NMDAR2B. The mean differences between groups were analyzed using one-way analysis of variance (ANOVA) with p < 0.05 considered statistically significant. RESULTS Ginger extracts and 6-shogaol alleviated hyperalgesia and allodynia. The groups that received ginger extract 400 mg/kgBW or 6-shogaol 15 mg/kgBW had significantly lower TRPV1 and NMDAR2B expressions in the spinal cord compared to the diabetic control group (p < 0.001; p < 0.05). However, no differences in volume of pancreatic islets (p > 0.05) nor insulin expression were observed in all PDN groups. CONCLUSION Ginger extracts and its compound, 6-shogaol, reduced pain symptoms in PDN via its effect on decreasing TRPV1 and NMDAR2B expressions in the spinal cord, with very limited effect on pancreatic islets.
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Affiliation(s)
- Fifteen Aprila Fajrin
- Department of Clinical and Community Pharmacy, Faculty of Pharmacy, Universitas Jember, Jember, 68121, Indonesia
| | - Agung Endro Nugroho
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
| | - Arief Nurrochmad
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
| | - Rina Susilowati
- Department of Histology and Cell Biology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.
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Sugimoto K, Murakami H, Deguchi T, Arimura A, Daimon M, Suzuki S, Shimbo T, Yagihashi S. Cutaneous microangiopathy in patients with type 2 diabetes: Impaired vascular endothelial growth factor expression and its correlation with neuropathy, retinopathy and nephropathy. J Diabetes Investig 2019; 10:1318-1331. [PMID: 30719863 PMCID: PMC6717820 DOI: 10.1111/jdi.13020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 01/21/2019] [Accepted: 01/31/2019] [Indexed: 12/14/2022] Open
Abstract
AIMS/INTRODUCTION To examine the three-dimensional morphology and vascular endothelial growth factor (VEGF) expression of skin microvasculature in patients with type 2 diabetes in relation to neuropathy, retinopathy and nephropathy. MATERIALS AND METHODS The present study enrolled 17 individuals with type 2 diabetes and 16 without. Skin sections were double-immunostained for type IV collagen and VEGF-A or protein gene product 9.5. Projected images from confocal microscopy served to quantify the occupancy rate of subepidermal type IV collagen-immunoreactive microvascular basement membrane area (OR-T4MBM), subepidermal VEGF-A-immunoreactive area and the VEGF/T4MBM ratio, as well as the protein gene product 9.5-immunoreactive intraepidermal nerve fiber density. Reduced intraepidermal nerve fiber density was applied for the diagnosis of neuropathy, fundic ophthalmoscopy and fluorescein angiography for retinopathy, and microalbuminuria or persistent proteinuria for nephropathy. RESULTS A total of 12 patients with diabetes had neuropathy, 10 had retinopathy and eight had nephropathy. Regardless of the presence or absence of neuropathy, retinopathy or nephropathy, OR-T4MBM was significantly increased in patients with diabetes compared with individuals without diabetes. In contrast, VEGF/T4MBM ratio was significantly decreased in those with neuropathy and retinopathy, as well as in those with and without nephropathy, whereas a trend toward a decreased VEGF/T4MBM ratio was seen in patients without retinopathy, as compared with individuals without diabetes. CONCLUSIONS The present study is the first report to show that cutaneous microangiopathy, as indicated by subepidermal microvascular proliferation and impaired VEGF expression, appears to occur before the development of overt clinical neuropathy, retinopathy or nephropathy in patients with type 2 diabetes.
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Affiliation(s)
| | - Hiroshi Murakami
- Department of Endocrinology and MetabolismHirosaki University Graduate School of MedicineHirosakiJapan
| | - Takahisa Deguchi
- Department of Diabetes and Endocrine MedicineKagoshima University Graduate School of Medical and Dental SciencesKagoshimaJapan
| | - Aiko Arimura
- Department of Diabetes and Endocrine MedicineKagoshima University Graduate School of Medical and Dental SciencesKagoshimaJapan
| | - Makoto Daimon
- Department of Endocrinology and MetabolismHirosaki University Graduate School of MedicineHirosakiJapan
| | - Susumu Suzuki
- Diabetes CenterOhta Nishinouchi HospitalKoriyamaJapan
| | - Takuro Shimbo
- Department of Internal MedicineOhta Nishinouchi HospitalKoriyamaJapan
| | - Soroku Yagihashi
- Department of Pathology and Molecular MedicineHirosaki University Graduate School of MedicineHirosakiJapan
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Grote CW, Wright DE. A Role for Insulin in Diabetic Neuropathy. Front Neurosci 2016; 10:581. [PMID: 28066166 PMCID: PMC5179551 DOI: 10.3389/fnins.2016.00581] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 12/06/2016] [Indexed: 12/13/2022] Open
Abstract
The peripheral nervous system is one of several organ systems that are profoundly affected in diabetes. The longstanding view is that insulin does not have a major role in modulating neuronal function in both central and peripheral nervous systems is now being challenged. In the setting of insulin deficiency or excess insulin, it is logical to propose that insulin dysregulation can contribute to neuropathic changes in sensory neurons. This is particularly important as sensory nerve damage associated with prediabetes, type 1 and type 2 diabetes is so prevalent. Here, we discuss the current experimental literature related to insulin's role as a potential neurotrophic factor in peripheral nerve function, as well as the possibility that insulin deficiency plays a role in diabetic neuropathy. In addition, we discuss how sensory neurons in the peripheral nervous system respond to insulin similar to other insulin-sensitive tissues. Moreover, studies now suggest that sensory neurons can also become insulin resistant like other tissues. Collectively, emerging studies are revealing that insulin signaling pathways are active contributors to sensory nerve modulation, and this review highlights this novel activity and should provide new insight into insulin's role in both peripheral and central nervous system diseases.
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Affiliation(s)
- Caleb W Grote
- Department of Anatomy and Cell Biology, University of Kansas Medical Center Kansas City, KS, USA
| | - Douglas E Wright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center Kansas City, KS, USA
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Tsukamoto M, Niimi N, Sango K, Takaku S, Kanazawa Y, Utsunomiya K. Neurotrophic and neuroprotective properties of exendin-4 in adult rat dorsal root ganglion neurons: involvement of insulin and RhoA. Histochem Cell Biol 2015; 144:249-59. [PMID: 26026990 DOI: 10.1007/s00418-015-1333-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2015] [Indexed: 11/26/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is thought to preserve neurons and glia following axonal injury and neurodegenerative disorders. We investigated the neurotrophic and neuroprotective properties of exendin (Ex)-4, a synthetic GLP-1 receptor (GLP-1R) agonist, on adult rat dorsal root ganglion (DRG) neurons and PC12 cells. GLP-1R was predominantly localized on large and small peptidergic neurons in vivo and in vitro, suggesting the involvement of GLP-1 in both the large and small sensory fiber functions. Ex-4 dose-dependently (1 ≤ 10 ≤ 100 nM) promoted neurite outgrowth and neuronal survival at 2 and 7 days in culture, respectively. Treatment with 100 nM Ex-4 restored the reduced neurite outgrowth and viability of DRG neurons caused by the insulin removal from the medium and suppressed the activity of RhoA, an inhibitory regulator for peripheral nerve regeneration, in PC12 cells. Furthermore, these effects were attenuated by co-treatment with phosphatidylinositol-3'-phosphate kinase (PI3K) inhibitor, LY294002. These findings imply that Ex-4 enhances neurite outgrowth and neuronal survival through the activation of PI3K signaling pathway, which negatively regulates RhoA activity. Ex-4 and other GLP-1R agonists may compensate for the reduced insulin effects on neurons, thereby being beneficial for the treatment of diabetic neuropathy.
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Affiliation(s)
- Masami Tsukamoto
- Diabetic Neuropathy Project (Former Laboratory of Peripheral Nerve Pathophysiology), Department of Sensory and Motor Systems, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan
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Downs CA, Faulkner MS. Toxic stress, inflammation and symptomatology of chronic complications in diabetes. World J Diabetes 2015; 6:554-565. [PMID: 25987953 PMCID: PMC4434076 DOI: 10.4239/wjd.v6.i4.554] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 12/30/2014] [Accepted: 02/12/2015] [Indexed: 02/05/2023] Open
Abstract
Diabetes affects at least 382 million people worldwide and the incidence is expected to reach 592 million by 2035. The incidence of diabetes in youth is skyrocketing as evidenced by a 21% increase in type 1 diabetes and a 30.5% increase in type 2 diabetes in the United States between 2001 and 2009. The effects of toxic stress, the culmination of biological and environmental interactions, on the development of diabetes complications is gaining attention. Stress impacts the hypothalamus-pituitary-adrenal axis and contributes to inflammation, a key biological contributor to the pathogenesis of diabetes and its associated complications. This review provides an overview of common diabetic complications such as neuropathy, cognitive decline, depression, nephropathy and cardiovascular disease. The review also provides a discussion of the role of inflammation and stress in the development and progression of chronic complications of diabetes, associated symptomatology and importance of early identification of symptoms of depression, fatigue, exercise intolerance and pain.
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12
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Kwai N, Arnold R, Poynten AM, Lin CSY, Kiernan MC, Krishnan AV. Continuous subcutaneous insulin infusion preserves axonal function in type 1 diabetes mellitus. Diabetes Metab Res Rev 2015; 31:175-82. [PMID: 25066412 DOI: 10.1002/dmrr.2583] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 07/17/2014] [Accepted: 07/18/2014] [Indexed: 01/22/2023]
Abstract
BACKGROUND Diabetic peripheral neuropathy is a common and debilitating complication of diabetes mellitus. Although strict glycaemic control may reduce the risk of developing diabetic peripheral neuropathy, the neurological benefits of different insulin regimens remain relatively unknown. METHODS In the present study, 55 consecutive patients with type 1 diabetes mellitus underwent clinical neurological assessment. Subsequently, 41 non-neuropathic patients, 24 of whom were receiving multiple daily insulin injections (MDII) and 17 receiving continuous subcutaneous insulin infusion (CSII), underwent nerve excitability testing, a technique that assesses axonal ion channel function and membrane potential in human nerves. Treatment groups were matched for glycaemic control, body mass index, disease duration and gender. Neurophysiological parameters were compared between treatment groups and those taken from age and sex-matched normal controls. RESULTS Prominent differences in axonal function were noted between MDII-treated and CSII-treated patients. Specifically, MDII patients manifested prominent abnormalities when compared with normal controls in threshold electrotonus (TE) parameters including depolarizing TE(10-20ms), undershoot and hyperpolarizing TE (90-100 ms) (P < 0.05). Additionally, recovery cycle parameters superexcitability and subexcitability were also abnormal (P < 0.05). In contrast, axonal function in CSII-treated patients was within normal limits when compared with age-matched controls. The differences between the groups were noted in cross-sectional analysis and remained at longitudinal follow-up. CONCLUSIONS Axonal function in type 1 diabetes is maintained within normal limits in patients treated with continuous subcutaneous insulin infusion and not with multiple daily insulin injections. This raises the possibility that CSII therapy may have neuroprotective potential in patients with type 1 diabetes.
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Affiliation(s)
- Natalie Kwai
- Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales, Sydney, Australia
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