ABSTRACT
Diabetic peripheral neuropathy (DPN) is one of the most common microvascular complications occurring in both type 1 and type 2 diabetes mellitus patients, which often results in patients suffering from severe hyperalgesia and allodynia. Up to now, the clinical therapeutic effect of DPN is still unsatisfactory. Metformin is an anti-diabetic drug that has been safely and widely used for the treatment of type 2 diabetes for decades. Studies have shown that metformin can improve pain caused by DPN, but its effects on the nerve conduction velocity and morphology of the sciatic nerve of DPN, and the mechanism for improving DPN are not clear. Therefore, the STZ-induced model of type 1 DPN in SD rats was used to study the effects of metformin on DPN, and to preliminarily explore its mechanism in this study. All animal experiments were carried out with approval of the Experimental Animal Welfare Ethics Committee of the Institute of Materia Medica (Chinese Academy of Medical Sciences and Peking Union Medical College). After the model was established successfully, STZ diabetic rats were randomly divided into a model group and a metformin treatment group, and 10 normal SD rats were selected as the normal control group, and the rats were intragastrically administered for 12 weeks. The results showed that metformin significantly reduced blood glucose, glycosylated hemoglobin, food consumption and water consumption in STZ rats. Metformin markedly increased the motor nerve conduction velocity and mechanical stabbing pain threshold, prolonged the hot plate latency threshold, and improved the pathological morphological abnormalities of the sciatic nerve in STZ rats. In addition, metformin increased the content of glutathione (GSH), enhanced the activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and reduced the content of malondialdehyde (MDA) in serum and sciatic nerve of STZ diabetic rats, as well as regulating the expression of genes related to oxidative stress in the sciatic nerve. Metformin obviously reduced the levels of pro-inflammatory factors such as tumor necrosis factor α (TNF-α), interleukin (IL)-1β and IL-6 in the serum in STZ rats, and inhibited the gene expression of these inflammatory factors in the sciatic nerve. In summary, metformin significantly increased nerve conduction velocity, improved sciatic nerve morphological abnormalities and pain in DPN rats, which may be related to its effect in improving oxidative stress and reducing inflammation.
ABSTRACT
Our previous studies have shown that puerarin, an active component of the traditional Chinese medicine-Pueraria Lobata, can improve glycometabolism in high-fat diet (HFD) mice with diabetes by activating the glucagon-like peptide-1 receptor (GLP-1R) pathway. This study intends to further evaluate the effect of puerarin on depressive symptoms in HFD mice. Long-term HFD induces type 2 diabetes and depressive-like symptoms in mice. Animal welfare and experimental procedures follow the regulations of the Animal Ethics Committee of the Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Traditional Chinese Medicine (approval No. AEWC-025). The experiment was divided into: control group, model group, model/puerarin (150 mg·kg-1·day-1) group, and model/fluoxetine (15 mg·kg-1·day-1) group. The oral glucose tolerance test (OGTT) and behavioral experimental analysis were performed after 6 weeks of continuous administration. Afterwards, enzyme-linked immunosorbent assay (ELISA) was used to detect interleukin-1β (IL-1β), interleukin-6 (IL-6), 5-hydroxytryptamine (5-HT), and corticosterone (CORT) in serum of mice for each group. Western blot assays were used to detect the level of activation and expression of proteins related to neuroplasticity and depressive disorder in the hippocampus. Moreover, HT-22 cell line was used to investigate the protective effect of puerarin on cell morphology and survival. The results show that puerarin can effectively maintain the survival of HT22 in an environment with high glucose and corticosterone. Meantime, the glycemic regulation of diabetic mice was improved after treatment of puerarin, the depressive symptoms were alleviated, the 5-HT increased, and the corticosterone, IL-1β, and IL-6 decreased in the serum. The up-regulation of related proteins in GLP-1R/Wnt/mTOR (mammalian target of rapamycin) signaling in hippocampus suggests that its effect on ameliorating depression in diabetic mice may be related to the activation of GLP-1R/Wnt/mTOR signaling pathway. This study shows that puerarin can significantly ameliorate the depressive symptoms of HFD induced diabetic mice which might be achieved through activating the GLP-1R/Wnt/mTOR signaling pathway and improving hippocampal neuroplasticity.
ABSTRACT
Metabolomics based on liquid chromatography coupled with mass spectrometry (LC-MS) was used to study the initiation and development of diabetes in rats, and the ability of Ginkgo biloba extract (GBE) to ameliorate this pathology. Diabetes mellitus (DM) was induced by intra-peritoneal injection of streptozotocin. The rats were randomly divided into a normal control group treated with drug-free solution (NC), a normal control group treated with GBE (N-GBE), a DM group treated with drug-free solution (DM), and a DM group treated with GBE (D-GBE); rats were maintained on this protocol for 9 weeks. Rat plasma was collected from the sixth week to the ninth week and then analyzed with LC-MS. Animal experimentation was approved by the Committee on the Ethics of Animal Experiments of Xuzhou Medical University. Twelve plasma metabolites with continuous differentiation were monitored to indicate dysfunction of metabolic pathways including fatty acid metabolism, phospholipid metabolism, amino acid metabolism, tricarboxylic acid cycle activity, bile acid metabolism, and purine metabolism to confirm the occurrence and development of DM. Treatment with GBE partially reversed the changes seen in five metabolites in DM rats, indicating that GBE could prevent the occurrence and development of DM by acting on fatty acid metabolism, phospholipid metabolism, amino acid metabolism, and the tricarboxylic acid cycle.
ABSTRACT
Type 2 diabetes is a complex metabolic disease, accompanied by insulin resistance and elevated blood glucose. As the disease progresses, hyperglucagonemia will occur. Glucagon has a significant effect on glucose increase and energy expenditure. In recent years, several glucagon receptor (GCGR) antagonists were developed. They lowered blood glucose in clinical studies, along with side effects, such as increased blood lipids and elevated liver transaminase. In order to solve these problems, glucagon like peptide 1 receptor (GLP-1R)/GCGR co-agonists were developed, which not only lower blood glucose, but also reduce weight and promote lipolysis. In this review, we will focus on the biological effects of glucagon, the treatments of GCGR antagonists, and GLP-1R/GCGR co-agonists on type 2 diabetes.
ABSTRACT
Thiazolidinediones (TZDs) are currently the only recognized insulin sensitizers available for the clinical treatment of type 2 diabetes. Although their advantages are recognized, the profiles of numerous adverse effects hinder the continued use of these drugs. Peroxisome proliferator-activated receptor γ (PPARγ) is known as a receptor for TZDs, and its underlying mechanisms of pharmacological actions and adverse effects have been deeply explored. To maximally preserve the PPARγ-mediated insulin sensitizing effects and reduce the occurrence of related adverse effects, the concept of "selective PPARγ modulators (SPPARMs)" has been proposed and developed, guiding the development of new drugs. In this review, we summarize the recent research progress in the definition of SPPARMs, the candidate classification and the molecular underpinnings, as well as present the discovery of the YR series compounds as an example, and discuss the potential application prospects of SPPARMs.
ABSTRACT
Fatigue is a common complication of type 2 diabetes mellitus (T2DM). We examined the relationship between T2DM fatigue and the skeletal muscle 5-hydroxytryptamine (5-HT) system. In animal experiments, a T2DM model was established in mice by feeding a high-fat diet with intraperitoneal injection of streptozotocin. The mice were treated with the 5-HT2A receptor antagonist sarpogrelate hydrochloride (SH) and the 5-HT synthesis inhibitor carbidopa (CDP) (separately and in combination). In cell culture experiments, C2C12 cells were stimulated with D-glucose, palmitic acid or 5-HT. 5-HT2AR, 5-HT synthesis and 5-HT degradation were inhibited by SH, CDP, or monoamine oxidase A (MAO-A) inhibitor. The animal experiments were in accordance with the regulations of the Animal Ethics Committee of China Pharmaceutical University. The results showed that 5-HT2AR, 5-HT synthase and MAO-A were expressed in mouse skeletal muscle and C2C12 cells. The expression of these proteins was significantly up-regulated in T2DM mice or when C2C12 cells were exposed to palmitic acid and D-glucose; palmitic acid was a stronger stimulant of their expression than D-glucose. Rotating rod experiments and biochemical index tests have shown that T2DM fatigue is associated with an increase in skeletal muscle 5-HT2AR, 5-HT synthesis and 5-HT degradation. 5-HT2AR mediates the expression of MAO-A and the synthesis of 5-HT, which indirectly regulates the degradation of 5-HT. MAO-A regulates cell inflammation, mitochondrial ROS production and membrane potential depolarization by mediating 5-HT degradation. MAO-A also inhibits the expression of peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1), carnitine palmitoyltransferase-1 (CPT1) and ATP synthase-6 (ATP6), thus inhibiting mitochondrial functions such as fatty acid β oxidation and ATP synthesis. SH and CDP can effectively treat T2DM fatigue, and can also reduce blood glucose and blood lipid, and the combination of SH and CDP has a clear synergistic effect.
ABSTRACT
Wound healing is a complex and highly regulated process to maintaining the skin barrier function. Wounds of diabetic patients are hard or even not healing. Non-healing diabetic foot ulcers can lead to lower-extremity amputations. Diabetic wound healing problem is the main complication that leads to high disability rate of diabetes and can threaten the lives in severe cases. The healing of skin wounds requires the synergy of multiple factors to restore the injured skin to its barrier function. The mechanisms that cause it difficult to heal diabetic wounds are complex, including oxidative stress, chronic inflammation, decreased neovascularization, peripheral neuropathy, and imbalance of extracellular matrix accumulation and remodeling. This review classifies mechanisms of diabetic wound healing and provides a reference for its further research.
ABSTRACT
Diabetes is characterized by hyperglycemia, resulting from insulin deficiency or resistance, or both. Insulin plays an irreplaceable role in the treatment of diabetes. Subcutaneous injection is the main route of insulin administration, but usually leads to poor compliance and many side effects. Oral insulin is safer and more convenient, which has always been the Holy Grail for people to explore. After oral administration, insulin is absorbed into the hepatic portal vein and transported to the liver, which can activate the normal physiological functions and reduce the risk of hypoglycemia, insulin resistance, and improve patient compliance. However, the gastrointestinal tract has multiple absorption barriers such as chemical barrier, enzyme barrier, and permeation barrier. Due to the physical and chemical properties of insulin, it is difficult to achieve desired oral bioavailability. This article reviews the recent attempts and progress in the field of oral administration of insulin driven by innovative drug delivery technologies and biomaterials, including structural modification, enzyme inhibitors, absorption enhancers, various nanoparticles, liposomes, microspheres, and even microorganisms. Some clinical researches on oral insulin are also introduced.
ABSTRACT
@#Malaysia seeks to transform its public healthcare sector to manage the growing number of people with diabetes. Patient engagement is a critical clinical competency for healthcare providers treating people with diabetes. In this study, we investigate the perceptions of and ability to practice patient engagement among doctors and nurses working in Malaysia’s primary healthcare system. Semi-structured interviews were conducted with nine non-specialist doctors and ten nurses working in primary healthcare clinics. Further, 12 key informants with specialist knowledge about diabetes care and the healthcare system in Malaysia were interviewed. The interviews were analyzed using qualitative content analysis. Three main themes emerged: 1) understanding barriers to self-care and treatment, 2) perceived training needs and skills within patient engagement and empowerment, and 3) challenges to the practice of patient engagement. A range of barriers was identified in healthcare providers’ ability to practice patient engagement. Future efforts should seek to improve competencies within patient engagement, identification of especially psychosocial barriers to self-care and empowerment. Yet, available manpower and time also influence whether patient engagement is practiced.
ABSTRACT
Seven main components in eleutheroside were used as research objects, and the mechanism of action of total eleutheroside for treatment of diabetes mellitus type 2 was investigated by network pharmacology. The SwissTargetPrediction, GeneCard, and String platforms were used to predict the 35 potential targets of these 7 components that are related to diabetes mellitus type 2. Then we used cytoscape 3.6.1 to build a "component-target" network map and used the Networkanalyzer tool for topology analysis. Gene ontology (GO) enrichment analysis and KEGG pathway enrichment analysis were performed on the DAVID6.8 platform, and the "component-target-path" network map was constructed based on the enrichment results. Those components mainly used in diabetes mellitus type 2 were screened as core components, and the core components were docked with key disease target proteins to verify the potential mechanism of the total eleutheroside. After screening, 8 important pathways associated with diabetes mellitus type 2 were identified. This study showed that eleutheroside A, eleutheroside D, eleutheroside E and sesamin played key roles in insulin resistance, apoptosis and inflammation pathways. The total eleutheroside may ameliorate type 2 diabetes mainly through regulating signal transducer and activator of transcription factors (STATs), non-receptor protein tyrosine phosphatase (PTPN) 1, PTPN2, c-Jun N-terminal kinase (JNK), and p38 mitogen activate protein kinase. These components worked together through multiple signaling pathway. Based on our data, eleutheroside is proposed as a novel therapeutic strategy for treatment of type 2 diabetes.
ABSTRACT
Diabetes is a metabolic disease with an extremely high incidence in China. In parallel with an increased incidence yearly, the population of diabetes is showing a trend towards younger age. Therefore, it is urgent to carry out research on diabetes in order to develop strategy for prevention. In recent years, metabolomics has made significant progress in the study of biomarkers, pathogenesis, early diagnosis and prognosis, and evaluation of drug efficacy in diabetes. However, limited by metabolomics technology and the complexity of diabetes research, metabolomics in the diabetes research remains challenging. We summarize the progress and prospect the future development of metabolomics in the diabetes research.