Experimental animal models for diabetes and its related complications-a review

Cocoa flavanol supplementation in optimizing post-exercise glycemic control in rats with normoglycemia or diabetes mellitus: findings from the ECODIA study

OBJECTIVE

This study investigated the acute effects of cocoa flavanol (CF) supplementation on glucose homeostasis, aerobic performance, and lactate concentration in rats with type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and normoglycemia (NORM).

MATERIALS AND METHODS

The study included 28 male Wistar rats (220-290 g). Induction of T1DM (n = 8) was achieved through intraperitoneal injection of streptozotocin, while T2DM (n = 10) was induced using an ad libitum high-fat diet combined with a fructose-rich beverage. The rats in the NORM group (n = 10) received a standard diet for 30 days. Two experiments were conducted: (1) T1DM rats performed two successive 30-minute treadmill runs below the anaerobic threshold and (2) T2DM and NORM rats underwent two incremental maximal treadmill running tests, both after CF or placebo supplementation. Blood glucose concentrations were measured from pre-exercise to 60 minutes post-exercise.

RESULTS

Glycemic reduction at 60 minutes post-exercise was significantly potentiated by CF compared with placebo supplementation in T1DM, T2DM, and normoglycemic rats (p < 0.05 for all). In T2DM rats, CF induced a glycemic response comparable to the NORM placebo-supplemented condition. These effects of CF persisted despite variations in aerobic performance or lactate concentration after incremental exercise.

CONCLUSION

Supplementation with CF prior to physical exercise elicited a pronounced post-aerobic exercise glycemic reduction. This represents a promising strategy for mitigating the duration of hyperglycemia exposure after physical exercise.

Controlled platelet-derived growth factor delivery by hyaluronic acid hydrogels with tunable crosslinking for accelerated chronic wound healing

Chronic wound healing is a complex process requiring sustained activity of growth factors across the whole healing process. Among these growth factors, platelet-derived growth factor (PDGF) plays a pivotal role. However, the short half-life of PDGF limits its therapeutic efficacy. This study introduces a hyaluronic acid-based hydrogel system loading with PDGF, MA-HA-Gelx/PDGF, designed for the controlled release of PDGF. By tuning the ratio of cross-linkers with different hydrolysis rates, the PDGF loaded hydrogel system ensures sustained release of bioactive PDGF. In vivo assays proved that, MA-HA-Gelx/PDGF could efficiently promote the proliferation and migration of fibroblasts. Furthermore, MA-HA-Gelx/PDGF could enhance neovascularization and accelerate the wound closure of a chronic wound bearing mouse model. This PDFG loaded hydrogel system offers a promising strategy for chronic wound treatment.

Tacrolimus and diabetic rodent models

Tacrolimus (TAC) is an immunosuppressant widely utilized in organ transplantation. One of its primary adverse effects is glucose metabolism disorder, which significantly increases the risk of diabetes. Investigating the molecular mechanisms underlying TAC-induced diabetes is essential for developing effective prevention and treatment strategies for these adverse effects. In addition, TAC can induce cost-effective, non-obese animal models of diabetes, where the metabolic parameter changes closely resemble those observed during the onset and progression of type 2 diabetes (T2DM), post-transplantation diabetes mellitus (PTDM), and associated complications. This review, based on articles indexed in PubMed up to August 19, 2024, identified 48 studies focusing on TAC-induced diabetic rodent models and 22 studies exploring the effects of TAC on diabetic or obese rodent models. These studies were systematically summarized based on TAC dosage, route of administration, duration of administration, and glucose metabolism indices used for evaluation. Additionally, the impact of TAC dose reduction or discontinuation on glucose metabolism was assessed, along with pharmacological agents that modulate TAC-induced diabetes, including anti-diabetic medications, anti-inflammatory and antioxidant compounds, biologics, and antibiotics. Key signaling pathways implicated in TAC-induced diabetes include CaN/NFAT, PI3K/AKT/mTOR, and TGF-β/Smad, all of which impair islet β-cell function, thereby contributing to diabetes development. This review provides a concise summary of the characteristics of relevant murine models, offering valuable guidance for selecting appropriate and economical animal models for future research.

The Zucker Diabetic Fatty Rat as a Model for Vascular Changes in Diabetic Kidney Disease: Characterising Hydronephrosis

Background/Objectives: Diabetic kidney disease (DKD) is a significant concern for global healthcare, particularly in individuals with diabetes. The Zucker rat strain is a commonly used model of type 2 diabetes, despite awareness that this animal can develop hydronephrosis. In this study, we present novel imaging data evaluating the accuracy of this animal model in replicating the vascular aspects of human DKD while examining the impact of hydronephrosis on its validity as a disease model. Methods: This study reused data from a population of male Zucker Diabetic Fatty (ZDF; n = 22) rats and Zucker Lean (ZL) rats (n = 22) aged 12 to approximately 40 weeks. Vascular casting was performed to enable visualisation of the renal vasculature. Anatomical regional volumes and vascular density data were obtained from μCT scans using image thresholding and manual analysis. The effects of hydronephrosis were evaluated using renal functional parameters and histological examination. Results: A significantly lower cortical vascular density, as well as lower total renal vascular density, was seen in ZDF rats compared to ZL rats, independent of age. We identified that hydronephrosis affected 92% of ZDF rats and 69% of ZL rats. Hydronephrosis cavity size was significantly correlated with the degree of hyperglycaemia and rate of diuresis but had no other detected impact on renal function, vascularity, or tissue histological architecture. Conclusions: These findings support using the Zucker rat strain as a model for vascular changes in DKD. Despite identifying severe hydronephrosis in this population, it had minimal quantifiable impact on renal function or diabetes modelling.

Targeted animal models for preclinical assessment of cellular and gene therapies in pancreatic and liver diseases: regulatory and practical insights

Cellular and gene therapy (CGT) products have emerged as a popular approach in regenerative medicine, showing promise in treating various pancreatic and liver diseases in numerous clinical trials. Before these therapies can be tested in human clinical trials, it is essential to evaluate their safety and efficacy in relevant animal models. Such preclinical testing is often required to obtain regulatory approval for investigational new drugs. However, there is a lack of detailed guidance on selecting appropriate animal models for CGT therapies targeting specific pancreatic and liver conditions, such as pancreatitis and chronic liver diseases. In this review, the gastrointestinal committee for the International Society for Cell and Gene Therapy provides a summary of current recommendations for animal species and disease model selection, as outlined by the US Food and Drug Administration, with references to EU EMA and Japan PMDA. We discuss a range of small and large animal models, as well as humanized models, that are suitable for preclinical testing of CGT products aimed at treating pancreatic and liver diseases. For each model, we cover the associated pathophysiology, commonly used metrics for assessing disease status, the pros and limitations of the models, and the relevance of these models to human conditions. We also summarize the use and application of humanized mouse and other animal models in evaluating the safety and efficacy of CGT products. This review aims to provide comprehensive guidance for selecting appropriate animal species and models to help bridge the gap between the preclinical research and clinical trials using CGT therapies for specific pancreatic and liver diseases.

Inhibition of repulsive guidance molecule A ameliorates diabetes-induced cognitive decline and hippocampal neurogenesis impairment in mice

Although diabetes mellitus is strongly associated with dementia, the mechanism underlying diabetes-induced cognitive dysfunction has not been clarified. Here, we demonstrate the vital role of repulsive guidance molecule A (RGMa) in the regulation of adult hippocampal neurogenesis and cognitive impairment under diabetic conditions. In type 2 diabetic db/db mice and streptozotocin-mediated type 1 diabetic mice, RGMa is upregulated in the granular cell layer of the dentate gyrus. Additionally, both neural stem cells (NSCs) and immature neurons express its receptor, neogenin. In vitro experiments revealed that high glucose-conditioned hippocampal neurons inhibited the differentiation of NSCs, and the application of an anti-RGMa antibody restored it. The treatment with an anti-RGMa antibody ameliorated diabetes-induced cognitive decline and impairment of hippocampal neurogenesis. These findings suggest that the RGMa negatively regulates hippocampal neurogenesis and is involved in diabetes mellitus-induced cognitive decline.

Mechanisms and early efficacy data of caloric restriction and caloric restriction mimetics in neurodegenerative disease

Neurodegenerative disorders (NDDs) have been prevalent for more than a decade, and the number of individuals affected per year has increased exponentially. Among these NDDs, Alzheimer's disease, which causes extreme cognitive impairment, and Parkinson's disease, characterized by impairments in motor activity, are the most prevalent. While few treatments are available for clinical practice, they have minimal effects on reversing the neurodegeneration associated with these debilitating diseases. Lifestyle modifications and dietary choices are emerging and promising approaches to combat these disorders. Of the lifestyle changes that one could adopt, a major habit is caloric restriction. Caloric restriction (CR) is a lifestyle modification in which the amount of calories ingested is reduced to a significant amount without resulting in malnutrition. However, maintaining such a lifestyle is challenging. As alternatives, certain compounds have been recognized to mimic the effects produced by CR. These compounds are called caloric restriction mimetics (CRMs). Among these compounds, some have been designated established CRMs, namely, resveratrol, metformin, and rapamycin, whereas several other candidates are termed potential CRMs because of a lack of conclusive evidence of their effects. The potential CRMs discussed in this review are quercetin, chrysin, astragalin, apigenin, curcumin, epigallocatechin-3-gallate, and NAD+ precursors. This review aims to provide an overview of these CRMs' effectiveness in preventing neurodegenerative disorders associated with aging. Moreover, we highlight the clinical relevance of these compounds by discussing in detail the results of clinical trials on them.

The Effect of Stem Cell Secretome on the Improvement of Diabetic Wound Recovery: A Systematic Review and Meta-Analysis of In Vivo Studies

Background

Diabetic wounds, characterized by their chronic nature, represent a critical challenge for patients with diabetes, often leading to amputation and mortality. Although stem cells show great promise, their use is limited by challenges related to stability and tumorigenicity. The secretome of stem cells, comprising molecules released by these cells, offers a potential alternative to the challenges associated with stem cell therapy and provides a promising solution for diabetic wound healing.

Objective

We conducted a systematic review and meta-analysis of relevant preclinical studies to evaluate the effectiveness of stem cell secretomes in treating diabetic wounds.

Methods

The protocol registration for this systematic review and meta-analysis was recorded in the PROSPERO database (CRD42023473726). Databases were searched from their inception until November 20, 2023. The quality assessment of the included studies was performed utilizing the CAMARADES 10-item Quality Checklist. Statistical analyses were conducted using a random-effects model to calculate standardized mean differences (SMD) and 95% confidence intervals (CI), with heterogeneity assessed via the I² statistic. The primary outcome evaluated was the wound closure rate, while secondary outcomes included parameters such as the number of fibroblasts, neutrophils, and macrophages.

Results

Twenty studies were included, comprising 382 animal subjects, and five of which were eligible for quantitative evaluation in a meta-analysis. The stem cell secretome significantly improved the wound closure rate (SMD = 9.63; 95% CI = 2.01 -17.25; P = 0.01, I2 = 76%) and reduced the number of neutrophils (SMD =  -8.47; 95% CI =  -13.05 to -3.90; P = 0.0003) and macrophages (SMD = -5.32; 95% CI = -9.09 to -1.55; P = 0.006).

Conclusion

This review suggests that stem cell secretomes have potential as a novel therapeutic strategy for diabetic wound healing, enhancing wound closure rates and reducing inflammation. These findings support the use of stem cell secretomes as a safer and more stable alternative to direct stem cell therapy, but further clinical studies are needed to confirm these results in human patients.

Diabetes Mellitus Impairs Blood-Brain Barrier Integrality and Microglial Reactivity

Diabetes mellitus (DM), a chronic metabolic disorder that adversely affects the blood-brain barrier (BBB) and microglial function in the central nervous system (CNS), contributing to neuronal damage and neurodegenerative diseases. However, the underlying molecular mechanisms linking diabetes to BBB dysfunction and microglial dysregulation remain poorly understood. Here, we assessed the impacts of diabetes on BBB and microglial reactivity and investigated its mechanisms. We found diabetes severely disrupted the BBB integrity and microglial response to vascular injury. We also revealed a potential relationship between BBB disruption and impaired microglial function, whereby increasing BBB permeability led to a downregulation of microglial P2RY12 expression, thereby impairing microglial protection against cerebrovascular injury. Understanding these mechanisms may contribute to the developing of therapeutic strategies for diabetes-related neurological complications.

Comprehensive review of animal models in diabetes research using chemical agents

Diabetes mellitus, characterized by insufficient insulin secretion and impaired insulin efficacy, disrupts carbohydrate, protein, and lipid metabolism. The global diabetic population is expected to double by 2025, from 380 million, posing a significant health challenge. Most diabetic individuals fall into the type 1 or type 2 categories, and diabetes adversely affects various organs, such as the kidneys, liver, nervous system, reproductive system, and eyes.This review focuses on animal models of diabetes induced by chemical agents, which are essential tools for understanding disease mechanisms, investigating complications, and testing antidiabetic drugs. Models include those caused by streptozotocin (STZ), alloxan, ferric nitrilotriacetate (Fe-NTA), dithizone, and anti-insulin serum.Streptozotocin (STZ)-induced diabetes models create type 1 and 2 diabetes by destroying pancreatic beta cells. The combination of STZ with nicotinamide mimics type 2 diabetes phenotypes. Alloxan induces a hyperglycemic state by causing free radical formation that selectively destroys pancreatic beta cells. Fe-NTA and dithizone also create diabetes models by damaging pancreatic beta cells. Anti-insulin serum models induce insulin resistance and hyperglycemia by generating antibodies against insulin receptors, leading to a condition similar to type 1 diabetes.Each model has unique characteristics that make it suitable for different aspects of diabetes research. These models are used to understand the pathogenesis of diabetes, develop new treatment strategies, and evaluate the efficacy of potential drugs.

A novel combination therapy using Dapagliflozin and Cycas media extract in experimentally induced diabetic wounds by targeting novel pathways in wound healing

Diabetes mellitus, a globally prevalent condition, often complicates wound healing, leading to chronic, non-healing wounds. This study explores a novel combination therapy using Dapagliflozin and Cycas media extract for treating experimentally induced diabetic wounds in rats. By targeting the Notch signaling pathway, a critical pathway in wound healing, this research investigates the efficacy of this combination therapy in accelerating wound repair. Forty-two male Wistar albino rats were divided into control and treatment groups, receiving various Dapagliflozin and Cycas media gel combinations. The study evaluated wound healing, biochemical markers, gene expression, and histopathological changes. The findings suggest that the combination therapy significantly enhances wound healing, modulates oxidative stress, alters inflammatory responses, and influences key genes in the Notch pathway. This research provides a new perspective on diabetic wound management and underlines the potential of combining Dapagliflozin and Cycas media as a therapeutic approach.

Molecular Findings Before Vision Loss in the Streptozotocin-Induced Rat Model of Diabetic Retinopathy

The streptozotocin-induced rat model of diabetic retinopathy presents similarities to the disease observed in humans. After four weeks following the induction of diabetes, the rats experience vision impairment. During this crucial four-week period, significant changes occur, with vascular damage standing out as a clinically significant factor, alongside neovascularization. While redox imbalance, activation of microglia, secretion of pro-inflammatory cytokines, and neuronal cell death are also observed, the latter remains an emerging hypothesis requiring further exploration. This review is a comprehensive and up-to-date chronological depiction of the progression of diabetic retinopathy within the initial four weeks of hyperglycemia, which precede the onset of vision loss. The data are structured in weekly changes. In the first week, oxidative stress triggers the activation of retinal microglia, which produces inflammation, leading to altered neurotransmission. The second week is characterized by leukostasis, which promotes ischemia, while neural degeneration begins and is accompanied by a simultaneous increase in vessel permeability. The progression of redox and inflammatory imbalances characterized the third week. Finally, in the fourth week, significant developments occur as vessels dilate and become tortuous, neovascularization develops, and retinal thickness diminishes, ultimately leading to vision loss. Through this clearly structured outline, this review aims to delineate a framework for the progression of streptozotocin-induced diabetic retinopathy.

Potentilla fulgens root extract rich in polyphenols ameliorate diabetic foot ulcers in wistar rats via regulating oxidative stress and connective tissue markers

BACKGROUND

Potentilla fulgens (Wall.) ex Hook. (Rosaceae), commonly known as 'Bajradanti' is native to the lower Himalayan regions inclusive of the North-East India. Traditionally, the plant is used to treat chronic ailments like diabetes and diverse wounds, including gastric and mouth ulcers, and injuries from tiger bites.

OBJECTIVE

This study aims to assess the efficacy of P. fulgens root extract rich in polyphenolics in healing diabetic foot ulcer (DFU) in rats.

METHODS

DFU was induced in streptozotocin-nicotinamide diabetic rat feet by open excision wound model. Rats were divided into eight groups (n = 6/group): normal, negative control, plain gel (placebo) control, 1% silver sulfadiazine, and P. fulgens treated with topical ethyl acetate (EAPF, 5% and 10%) and methanol extract (MEPF, 5% and 10%). The morphological, histological and various biochemical parameters associated with the wound healing process such as connective tissue repair and oxidative stress biomarkers were evaluated.

RESULTS

Topical application of EAPF 10% and MEPF 10% over 21 days significantly (p < 0.05) reduced ulcer area in DFU rats compared to negative control. Furthermore, the extracts treated group notably (p < 0.05) increased levels of connective tissue biomarkers (total protein, hydroxyproline, hexosamine, and hexuronic acid) and antioxidant components (SOD and GSH), while significantly (p < 0.05) decreasing levels of lipid peroxidation (LPO) in foot tissue homogenate. Histological analysis of rats treated with the extracts revealed significant evidence of tissue repair, characterised by enhanced epithelial and collagen formation, along with decreased polymorphonuclear infiltration and edema.

CONCLUSION

In summary, treatment with EAPF 10% significantly improved foot ulcers by modulating oxidative stress and connective tissue biomarkers in DFU animals.

Harnessing cellular therapeutics for type 1 diabetes mellitus: progress, challenges, and the road ahead

Type 1 diabetes mellitus (T1DM) is a growing global health concern that affects approximately 8.5 million individuals worldwide. T1DM is characterized by an autoimmune destruction of pancreatic β cells, leading to a disruption in glucose homeostasis. Therapeutic intervention for T1DM requires a complex regimen of glycaemic monitoring and the administration of exogenous insulin to regulate blood glucose levels. Advances in continuous glucose monitoring and algorithm-driven insulin delivery devices have improved the quality of life of patients. Despite this, mimicking islet function and complex physiological feedback remains challenging. Pancreatic islet transplantation represents a potential functional cure for T1DM but is hindered by donor scarcity, variability in harvested cells, aggressive immunosuppressive regimens and suboptimal clinical outcomes. Current research is directed towards generating alternative cell sources, improving transplantation methods, and enhancing cell survival without chronic immunosuppression. This Review maps the progress in cell replacement therapies for T1DM and outlines the remaining challenges and future directions. We explore the state-of-the-art strategies for generating replenishable β cells, cell delivery technologies and local targeted immune modulation. Finally, we highlight relevant animal models and the regulatory aspects for advancing these technologies towards clinical deployment.

Deciphering the Anti-Diabetic Potential of Gymnema Sylvestre Using Integrated Computer-Aided Drug Design and Network Pharmacology

This study explores novel therapeutic avenues for diabetes, a global health concern marked by elevated blood glucose levels. We investigated the anti-diabetic potential of Gymnema Sylvestre's bioactive compounds, including Gymnemic acid I, Stigmasterol, Deacylgymnemic acid, Beta-Amyrin acetate, Longispinogenin, Gymnemic acid II, Gymnemic acid, Gymnemic acid X, Gymnemaside VI, Phytic acid and Gymnemic acid X. Employing network pharmacology, molecular docking and molecular dynamics (MD), we elucidated the potential mechanism of action. SwissTargetPrediction identified targets for bioactive constituents, while DisGeNET provided diabetes-related targets. A GeneVenn diagram revealed 397 common potential targets for diabetes management. The protein-protein interaction network, constructed via the STRING database, underwent topological analysis in Cytoscape, identifying AKT1, SRC, TNF, PPARG and IL1B as top targets. Gene ontology analysis using FunRich identified crucial roles of screened targets in integrin family cell surface interactions and glypican pathways for diabetes management. Molecular interactions and binding affinities with the top target, AKT1, were assessed, with Gymnemic acid I displaying the least binding energy (-9.813) with H- and non-H-bond interactions. Molecular dynamics simulations provided insights into the distinct behaviours of Gymnemic acid I within the protein complex. In conclusion, our study elucidates the potential anti-diabetic mechanism of Gymnemic acid I, underscoring the need for further in vitro, in vivo and clinical studies to validate our findings.

Phylogenomic analyses of hamsters (Cricetinae) inferred from GBS data and mitochondrial genomes

Accurate species delimitation and identification is crucial for species conservation, providing a foundation for studies on evolutionary biology, ecology, and essentially all biological disciplines. The subfamily Cricetinae (Cricetidae, Rodentia), known as hamsters, is widely distributed in the Palearctic region. At present, there are nine genera and 18 species of hamsters are recognized worldwide, although the taxonomic status of certain taxa remains unclear. In this study, we collected 146 hamster specimens representing 14 species and generated new mitochondrial genomes and nuclear genome-wide single nucleotide polymorphisms (SNPs) to explore their relationships among these hamsters using multiple species delimitation approaches. Results showed: (1) strong phylogenetic support for the classification of Urocricetus, Nothocricetulus, and Cansumys as separate genera; (2) Urocricetus contained two separate species, U. kamensis and U. lama, with U. alticola and U. tibetanus considered synonyms of U. lama; (3) U. kamensis and U. lama are separated by the Nujiang River, with the matching divergence time suggesting that the formation of the river was the primary evolutionary factor driving the species differentiation, and (4) genetic differentiation occurred within the Tscherskia genus, which included two cryptic species.

Natural Compounds in Kidney Disease: Therapeutic Potential and Drug Development

Diabetic kidney disease (DKD) poses a major global health challenge, affecting millions of individuals and contributing to substantial morbidity and mortality. Traditional treatments have focused primarily on managing symptoms and slowing disease progression rather than reversing or halting kidney damage. However, recent advancements in natural compound research have unveiled promising new avenues for therapeutic development. Extensive research has been conducted to showcase the antioxidant advantages for kidney health, supporting the potential effectiveness of natural and synthetic products in clinical and experimental research. Bioactive substances found in large quantities in food, such as polyphenols, have emerged as adjuvants. This review manuscript aims to provide a comprehensive overview of natural compounds and their potential efficacy, mechanisms of action, and clinical applications in the prevention and treatment of various kidney diseases. This review emphasizes the connection between oxidative stress and inflammation in diabetic nephropathy (DN), which leads to harmful effects on kidney cells due to pathological damage. A lower incidence of DM2-related problems and a slower progression of end-stage renal disease have been associated with the consumption of these compounds.

The Wound Reporting in Animal and Human Preclinical Studies (WRAHPS) Guidelines

Preclinical studies for wound healing disorders are an essential step in translating discoveries into therapies. Also, they are an integral component of initial safety screening and gaining mechanistic insights using an in vivo approach. Given the complexity of the wound healing process, existing guidelines for animal testing do not capture key information due to the inevitable variability in experimental design. Variations in study interpretation are increased by complexities associated with wound aetiology, wounding procedure, multiple treatment conditions, wound assessment, and analysis, as well as lack of acknowledgement of limitation of the model used. Yet, no standards exist to guide reporting crucial experimental information required to interpret results in translational studies of wound healing. Consistency in reporting allows transparency, comparative, and meta-analysis studies and avoids repetition and redundancy. Therefore, there is a critical and unmet need to standardise reporting for preclinical wound studies. To aid in reporting experimental conditions, The Wound Reporting in Animal and Human Preclinical Studies (WRAHPS) Guidelines have now been created by the authors working with the Wound Care Collaborative Community (WCCC) GAPS group to provide a checklist and reporting template for the most frequently used preclinical models in support of development for human clinical trials for wound healing disorders. It is anticipated that the WRAHPS Guidelines will standardise comprehensive methods for reporting in scientific manuscripts and the wound healing field overall. This article is not intended to address regulatory requirements but is intended to provide general guidelines on important scientific considerations for such studies.

Exploring the Potential of Epigallocatechin Gallate in Combating Insulin Resistance and Diabetes

BACKGROUND/OBJECTIVES

In this study, the potential effects are evaluated of epigallocatechin gallate (EGCG) on the prognosis of diabetes and insulin resistance.

METHODS

In an experiment, 35 male Wistar albino rats were used and in the streptozotocin (STZ)-induced diabetic rats, the effects were examined of different doses (50 mg/kg, 100 mg/kg, 200 mg/kg) of EGCG on metabolic parameters associated with diabetes and insulin resistance.

RESULTS

The findings show favorable effects of EGCG on fasting blood glucose levels, insulin secretion, insulin resistance, and beta cell function. In this study, it was observed that EGCG was able to significantly lower fasting blood glucose levels, especially at high doses (200 mg/kg), providing the most significant improvement. Furthermore, EGCG has been found to reduce insulin resistance and improve insulin sensitivity by increasing insulin secretion. When the biochemical parameters of increased insulin secretion are evaluated, it is also observed that it creates clinically significant changes. At doses of 100 mg/kg and 200 mg/kg, EGCG has the potential to help control diabetes by most effectively improving insulin resistance and beta cell function. The study results suggest that EGCG, especially at high doses, is an effective component in the treatment of diabetes and the management of insulin resistance.

CONCLUSIONS

The inclusion of EGCG as a natural flavonoid in medical nutrition therapy may contribute to glycemic control and improve insulin sensitivity in individuals with diabetes. These findings suggest that EGCG may be used as an alternative option in the treatment of diabetes and future studies may further clarify the potential benefits in this area.

The Alteration of Proteomic Profiles in Hippocampus of Type 2 Diabetic Mice Associated With Cognitive Impairment

Clinical and experimental studies have demonstrated that type 2 diabetes mellitus (T2DM) affects the brain structure and function, in particular the hippocampus, leading to cognitive impairments. However, the molecular mechanisms underlying cognitive deficits induced by T2DM are not fully understood. In this study, we aimed to investigate the effects of T2DM on behavior, the proteome profile in the hippocampus, and the potential molecular pathways involved in the development of cognitive dysfunction in T2DM mice. We found that the diabetic mice exhibited cognitive impairment in the novel object location recognition test and the novel object recognition test. The proteomic analysis revealed that various molecular pathways were involved in this context. These included the upregulation of proteins in the protein synthesis and folding pathway (EIF5A, RSP24, and PPIB), endocytosis and cellular trafficking (VPS24, SNX12, and ARP2/3), cannabinoid receptor interacting (CRIP1), ubiquitination (SKP1), and oxidative stress response (NUDT3). Downregulated proteins were related to mitochondria function (ANT1), neuronal development (ELP1), protein glycosylation (RPN2), and endocytosis (VPS4). Our study shows that T2DM mice exhibit neurocognitive impairment, which is linked to the dysregulation of hippocampal proteins involved in various molecular pathways. These findings contribute to a better understanding of the pathophysiology of T2DM-related cognitive impairment and may identify molecular targets for drug development to treat T2DM-associated cognitive impairment conditions.

Advanced drug delivery strategies for diabetic retinopathy: current therapeutic advancement, and delivery methods overcoming barriers, and experimental modalities

INTRODUCTION

Diabetic retinopathy, a significant trigger for blindness among working age individuals with diabetes, poses a substantial global health challenge. Understanding its underlying mechanisms is pivotal for developing effective treatments. Current treatment options, such as anti-VEGF agents, corticosteroids, laser photocoagulation, and vitreous surgery, have their limitations, prompting the exploration of innovative approaches like nanocapsules based drug-delivery systems. Nanoparticles provide promising solutions to improve drug delivery in ocular medicine, overcoming the complexities of ocular anatomy and existing treatment constraints.

AREAS COVERED

This review explored advanced therapeutic strategies for diabetic retinopathy, focusing on current medications with their limitations, drug delivery methods, device innovations, and overcoming associated barriers. Through comprehensive review, it aimed to contribute to the discovery of more efficient management strategies for diabetic retinopathy in the future.

EXPERT OPINION

In the next five to ten years, we expect a revolutionary shift in how diabetic retinopathy is treated. As we deepen our understanding of oxidative stress and metabolic dysfunction, antioxidants with specialised delivery matrices are poised to take center stage in prevention and treatment strategies. Our vision is to create a more integrated approach to diabetic retinopathy management that not only improves patient outcomes but also reduces the risks associated to traditional therapies.

Advances in microbial exopolysaccharides as α-amylase inhibitors: Effects, structure-activity relationships, and anti-diabetic effects in vivo

The rapid digestion of starch, as the main source of energy in the human diet, causes an acute increase in blood sugar levels that will affect blood glucose homeostasis. The inhibition of α-amylase activity is an effective way of reducing starch digestibility, thereby controlling postprandial glycemia. As a class of carbohydrate polymers, microbial exopolysaccharides (EPSs) have garnered widespread attention for their inhibitory effects on α-amylase, but there is a lack of comprehensive review in this area. This paper aimed to review the inhibitory activity of microbial EPSs on α-amylase and their interaction mechanisms, and the effect of microbial EPSs on lowering blood glucose levels and regulating glycolipid metabolism in vivo were also discussed. Numerous studies have reported that EPSs with α-amylase inhibition activity are primarily produced by lactic acid bacteria. Microbial EPSs with an appropriate range of molecular weight, high proportion of glucose or mannose or arabinose residues, and high uronic acid content might be acceptable to inhibit α-amylase activity. Additionally, microbial EPSs exhibited potential anti-diabetic effects in mice, reducing blood glucose levels, and regulating glycolipid metabolism and gut microbiota. The information covered in this review may enhance the development and application of EPSs in functional food and pharmaceutical research.

Diminished light sensitivities of ON alpha retinal ganglion cells observed in a mouse model of hyperglycemia

This study aimed to investigate potential functional changes in retinal ganglion cells (RGCs) in a mouse model of hyperglycemia and explore possible therapeutic approaches. Hyperglycemia resembling type 1 diabetes mellitus (DM) was induced in C57BL/6 mice through intraperitoneal injection of streptozotocin (STZ). Blood glucose levels were confirmed to be elevated after 1 week and 4 weeks of injection. Mice with blood glucose levels above 350 mg/mL after 4 weeks of one-dose STZ injection were considered hyperglycemic. The light sensitivity of ON alpha (α) retinal ganglion cells (RGCs), not OFF αRGCs, was reduced in the hyperglycemic mouse model. The number of apoptotic cells, RGCs, and amacrine cells (ACs) remained unaffected at this stage. Similarly, the eletroretinogram (ERG) and optokinetic test results showed no significant differences. The application of picrotoxin (PTX) to block GABA receptors could increase the light sensitivity of ON αRGCs by 1 log unit in hyperglycemic mice. The results show that ON αRGCs may be more susceptible to microenvironmental changes caused by hyperglycemia than OFF αRGCs. This decline in light sensitivity may occur before cell apoptosis during the early stages of the hyperglycemic mouse model but has the potential to be reversed.

Type 2 diabetes remodels collateral circulation and promotes leukocyte adhesion following ischemic stroke

Type 2 diabetes mellitus (T2DM) is associated with impaired leptomeningeal collateral compensation and poor stroke outcome. Neutrophils tethering and rolling on endothelium after stroke can also independently reduce flow velocity. However, the chronology and topological changes in collateral circulation in T2DM is not yet defined. Here, we describe the spatial and temporal blood flow dynamics and vessel remodeling in pial arteries and veins and leukocyte-endothelial adhesion following middle cerebral artery (MCA) stroke using two-photon microscopy in awake control and T2DM mice. Relative to control mice prior to stroke, T2DM mice already exhibited smaller pial vessels with reduced flow velocity. Following stroke, T2DM mice displayed persistently reduced blood flow in pial arteries and veins, resulting in a poor recovery of downstream penetrating arterial flow and a sustained deficit in microvascular flow. There was also persistent increase of leukocyte adhesion to the endothelium of veins, coincided with elevated neutrophils infiltration into brain parenchyma in T2DM mice compared to control mice after stroke. Our data suggest that T2DM-induced increase in chronic inflammation may contribute to the remodeling of leptomeningeal collateral circulation and the observed hemodynamics deficiency that potentiates poor stroke outcome.

Sexual Dimorphism in Impairment of Acetylcholine-Mediated Vasorelaxation in Zucker Diabetic Fatty (ZDF) Rat Aorta: A Monogenic Model of Obesity-Induced Type 2 Diabetes

Several reports, including our previous studies, indicate that hyperglycemia and diabetes mellitus exert differential effects on vascular function in males and females. This study examines sex differences in the vascular effects of type 2 diabetes (T2D) in an established monogenic model of obesity-induced T2D, Zucker Diabetic Fatty (ZDF) rats. Acetylcholine (ACh) responses were assessed in phenylephrine pre-contracted rings before and after apocynin, a NADPH oxidase (NOX) inhibitor. The mRNA expressions of aortic endothelial NOS (eNOS), and key NOX isoforms were also measured. We demonstrated the following: (1) diabetes had contrasting effects on aortic vasorelaxation in ZDF rats, impairing relaxation to ACh in females while enhancing it in male ZDF rats; (2) inhibition of NOX, a major source of superoxide in vasculature, restored aortic vasorelaxation in female ZDF rats; and (3) eNOS and NOX4 mRNA expressions were elevated in female (but not male) ZDF rat aortas compared to their respective leans. This study highlights sexual dimorphism in ACh-mediated vasorelaxation in the aorta of ZDF rats, suggesting that superoxide may play a role in the impaired vasorelaxation observed in female ZDF rats.

Wharton's Jelly Mesenchymal Stem Cell Conditioned Medium Ameliorates Diabetes-Induced Testicular Damage and Sperm Abnormalities by Mitigating Oxidative Stress, Apoptosis, and Inflammation

Diabetes leads to testicular damage and infertility. Mesenchymal stem cells and their secretory trophic factors have shown potential as regenerative therapies for diabetes and its associated complications. This study examined the effects of conditioned medium derived from Wharton's jelly mesenchymal stem cells (WJMSCs-CM) on sperm parameters, reproductive hormones, biochemical parameters, and histological changes in the testes of diabetic rats. Fifty-six male Sprague-Dawley rats (250-300 g) were assigned to eight groups: control, diabetes, and six diabetic groups receiving early or late treatments with WJMSCs-CM (D-CME, D-CML), insulin (D-INSE, D-INSL), or DMEM (D-DME, D-DML). In the early treatment groups, insulin (3 U/day, subcutaneously) and WJMSCs-CM (10 mg/week, intraperitoneally) were administered immediately after diabetes induction; in the late treatment groups, these interventions began 30 days postinduction. Blood glucose and insulin levels, along with sperm parameters, were assessed. Sex hormones, testicular antioxidant enzyme activity, malondialdehyde (MDA), and glutathione (GSH) concentrations were measured using colorimetric methods. Real-time PCR detected Bax, Bcl-2, and tumor necrosis factor-alpha (TNF-α) gene expression. Our results showed that diabetes increased blood glucose levels, decreased insulin and sex hormone levels, induced testicular oxidative stress and apoptosis, and reduced sperm parameters compared to the control. WJMSCs-CM significantly ameliorated hyperglycemia, increased insulin and sex hormone levels, and improved sperm quality. In WJMSCs-CM-treated diabetic rats, MDA levels were reduced, while GSH and antioxidant enzyme activity increased. Furthermore, WJMSCs-CM decreased the testicular Bax/Bcl-2 ratio and TNF-α expression, as well as enhanced spermatogenic, Sertoli, and Leydig cells. In conclusion, WJMSC-CM administration effectively mitigated diabetes-induced testicular damage by reducing oxidative stress, inflammation, and apoptosis. Early treatment with WJMSCs-CM was more effective than late treatment for diabetes-induced reproductive dysfunction.

The screening of α-glucosidase inhibitory peptides from β-conglycinin and hypoglycemic mechanism in HepG2 cells and zebrafish larvae

Inhibition of carbohydrate digestive enzymes is a key focus across diverse fields, given the prominence of α-glucosidase inhibitors as preferred oral hypoglycaemic drugs for diabetes treatment. β-conglycinin is the most abundant functional protein in soy; however, it is unclear whether the peptides produced after its gastrointestinal digestion exhibit α-glucosidase inhibitory properties. Therefore, we examined the α-glucosidase inhibitory potential of soy peptides. Specifically, β-conglycinin was subjected to simulated gastrointestinal digestion by enzymatically cleaving it into 95 peptides with gastric, pancreatic and chymotrypsin enzymes. Eight soybean peptides were selected based on their predicted activity; absorption, distribution, metabolism, excretion and toxicity score; and molecular docking analysis. The results indicated that hydrogen bonding and electrostatic interactions play important roles in inhibiting α-glucosidase, with the tripeptide SGR exhibiting the greatest inhibitory effect (IC50 = 10.57 μg/mL). In vitro studies revealed that SGR markedly improved glucose metabolism disorders in insulin-resistant HepG2 cells without affecting cell viability. Animal experiments revealed that SGR significantly improved blood glucose and decreased maltase activity in type 2 diabetic zebrafish larvae, but it did not result in the death of zebrafish larvae. Transcriptomic analysis revealed that SGR exerts its anti-diabetic and hypoglycaemic effects by attenuating the expression of several genes, including Slc2a1, Hsp70, Cpt2, Serpinf1, Sfrp2 and Ggt1a. These results suggest that SGR is a potential food-borne bioactive peptide for managing diabetes.

Experimental approaches for induction of diabetes mellitus and assessment of antidiabetic activity: An in vitro and in vivo methodological review

BACKGROUND

Diabetes mellitus poses a global health challenge, driving the need for innovative therapeutic solutions. Experimental methods play a crucial role in evaluating the efficacy of potential antidiabetic drugs, both in vitro and in vivo. Yet concerns about reproducibility persist, necessitating comprehensive reviews.

OBJECTIVES

This review aims to outline experimental approaches for inducing diabetes and evaluating antidiabetic activity, synthesizing data from authoritative sources and academic literature.

METHODS

We conducted a systematic search of prominent databases, including PubMed, ScienceDirect, and Scopus, to identify relevant articles spanning from 1943 to the present. A total of 132 articles were selected for inclusion in this review, focusing on in vitro and in vivo experimental validations of antidiabetic treatments.

RESULTS

Our review highlights the diverse array of experimental methods employed for inducing diabetes mellitus and evaluating antidiabetic interventions. From cell culture assays to animal models, researchers have employed various techniques to study the effectiveness of novel therapeutic agents.

CONCLUSION

This review provides a comprehensive guide to experimental approaches for assessing antidiabetic activity. By synthesizing data from a range of sources, we offer valuable insights into the current methodologies used in diabetes research. Standardizing protocols and enhancing reproducibility are critical for advancing effective antidiabetic treatments.

Edible mushroom (Pleurotus cornucopiae) extract vs. glibenclamide on alloxan induced diabetes: sub-acute in vivo study of Nrf2 expression and renal toxicity

The study aims to compare the action of Pleurotus cornucopiae and glibenclamide on alloxan-induced diabetes and ascertain how an aqueous extract of the edible mushroom regulates the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), oxidative stress biomarkers and renal toxicity in a diabetic male Wistar rat model. Twenty-five adult male Wistar rats were randomly grouped into five groups with five rats per. Group 1 and those in the treatment groups received normal feed and water ad libitum. Group 2 received intraperitoneal administration of alloxan monohydrate (150 mg/kg body weight). Group 3 received alloxan monohydrate and glibenclamide (5 mg/kg body weight bwt), group 4 received alloxan monohydrate plus the extract (250 mg/kg bwt) and group 5 received alloxan monohydrate plus the extract (500 mg/kg bwt). The administration of glibenclamide plus the extract was oral for 14 days. Glibenclamide and the extract lowered blood glucose level, catalase, and glutathione peroxidase activities, increased the superoxide dismutase (SOD) activity in rats with alloxan induced diabetes. The extract at 500 mg/kg bwt reduced the plasma urea and sodium concentration in the treated rats. The extract and glibenclamide could detoxify alloxan and restore its induced renal degeneration and glomeruli atrophy, intra renal hemorrhage and inflammation and oxidative biomarkers through activation of Nrf2 expression. The drug glibenclamide and P. cornucopiae have appreciable hypoglycemic activity and potential to restore the normal renal architecture in the rats, hence they offer similar curative effects. Additionally, the extract at 500 mg/kg bwt activated SOD and Nrf2 expression more than glibenclamide in rats with alloxan-induced diabetes.

Highly Miniaturized, Low-Power CMOS ASIC Chip for Long-Term Continuous Glucose Monitoring

BACKGROUND

The objective of this work is to develop a highly miniaturized, low-power, biosensing platform for continuous glucose monitoring (CGM). This platform is based on an application-specific integrated circuit (ASIC) chip that interfaces with an amperometric glucose-sensing element. To reduce both size and power requirements, this custom ASIC chip was implemented using 65-nm complementary metal oxide semiconductor (CMOS) technology node. Interfacing this chip to a frequency-counting microprocessor with storage capabilities, a miniaturized transcutaneous CGM system can be constructed for small laboratory animals, with long battery life.

METHOD

A 0.45 mm × 1.12 mm custom ASIC chip was first designed and implemented using the Taiwan Semiconductor Manufacturing Company (TSMC) 65-nm CMOS technology node. This ASIC chip was then interfaced with a multi-layer amperometric glucose-sensing element and a frequency-counting microprocessor with storage capabilities. Variation in glucose levels generates a linear increase in frequency response of this ASIC chip. In vivo experiments were conducted in healthy Sprague Dawley rats.

RESULTS

This highly miniaturized, 65-nm custom ASIC chip has an overall power consumption of circa 36 µW. In vitro testing shows that this ASIC chip produces a linear (R2 = 99.5) frequency response to varying glucose levels (from 2 to 25 mM), with a sensitivity of 1278 Hz/mM. In vivo testing in unrestrained healthy rats demonstrated long-term CGM (six days/per charge) with rapid glucose response to glycemic variations induced by isoflurane anesthesia and tail vein injection.

CONCLUSIONS

The miniature footprint of the biosensor platform, together with its low-power consumption, renders this CMOS ASIC chip a versatile platform for a variety of highly miniaturized devices, intended to improve the quality of life of patients with type 1 and type 2 diabetes.

Association Between Type 2 Diabetes Mellitus and Alzheimer's Disease: Common Molecular Mechanism and Therapeutic Targets

Diabetes mellitus (DM) and Alzheimer's disease (AD) rates are rising, mirroring the global trend of an aging population. Numerous epidemiological studies have shown that those with Type 2 diabetes (T2DM) have an increased risk of developing dementia. These degenerative and progressive diseases share some risk factors. To a large extent, the amyloid cascade is responsible for AD development. Neurofibrillary tangles induce neurodegeneration and brain atrophy; this chain reaction begins with hyperphosphorylation of tau proteins caused by progressive amyloid beta (Aβ) accumulation. In addition to these processes, it seems that alterations in brain glucose metabolism and insulin signalling lead to cell death and reduced synaptic plasticity in AD, before the onset of symptoms, which may be years away. Due to the substantial evidence linking insulin resistance in the brain with AD, researchers have coined the name "Type 3 diabetes" to characterize the condition. We still know little about the processes involved, even though current animal models have helped illuminate the links between T2DM and AD. This brief overview discusses insulin and IGF-1 signalling disorders and the primary molecular pathways that may connect them. The presence of GSK-3β in AD is intriguing. These proteins' association with T2DM and pancreatic β-cell failure suggests they might be therapeutic targets for both disorders.

Antidiabetic and Anti-Inflammatory Effect of Cinnamomum cassia Oil in Alloxan-Induced Diabetic Rats

Diabetes mellitus presents a great diversity of treatments that cause adverse effects; therefore, plants are a source of compounds that may have fewer adverse effects; Cinnamomum cassia (C. cassia) has compounds with potential antidiabetic activity. The objective was to evaluate the antidiabetic effect of C. cassia oil (CCO) and its impact on oxidative stress in Wistar rats. Five groups were evaluated: (1) sham (SH), (2) 300 mg/kg CCO (CCO), (3) diabetic (D) induced with alloxan, (4) D + 300 mg/kg of CCO (D + CCO), and (5) D + 500 mg/kg of metformin (D + MET); all were treated for 5 days. CCO did not show alteration in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) vs. SH. D + CCO vs. D significantly reduced glucose (333 ± 109 vs. 458 ± 81 mg/dL), ALT (66 ± 15 vs. 160 ± 54 U/L), AST (119 ± 26 vs. 243 ± 104 U/L), and blood urea nitrogen (18.8 ± 2.3 vs. 29.2 ± 6.9 mg/dL). No significant changes were observed in D + CCO vs. D in malondialdehyde (MDA), reduced glutathione (GSH), and superoxide dismutase (SOD), whereas a significant reduction in MDA and GSH was achieved in D + MET, with an increase in SOD. There was a reduction in Rela and Gpx in D + CCO and D + MET vs. D. CCO has antidiabetic and anti-inflammatory effects and reduces ALT, AST, and BUN levels.

The Synergistic Effects of Polyol Pathway-Induced Oxidative and Osmotic Stress in the Aetiology of Diabetic Cataracts

Cataracts are the world's leading cause of blindness, and diabetes is the second leading risk factor for cataracts after old age. Despite this, no preventative treatment exists for cataracts. The altered metabolism of excess glucose during hyperglycaemia is known to be the underlying cause of diabetic cataractogenesis, resulting in localised disruptions to fibre cell morphology and cell swelling in the outer cortex of the lens. In rat models of diabetic cataracts, this damage has been shown to result from osmotic stress and oxidative stress due to the accumulation of intracellular sorbitol, the depletion of NADPH which is used to regenerate glutathione, and the generation of fructose metabolites via the polyol pathway. However, differences in lens physiology and the metabolism of glucose in the lenses of different species have prevented the translation of successful treatments in animal models into effective treatments in humans. Here, we review the stresses that arise from hyperglycaemic glucose metabolism and link these to the regionally distinct metabolic and physiological adaptations in the lens that are vulnerable to these stressors, highlighting the evidence that chronic oxidative stress together with osmotic stress underlies the aetiology of human diabetic cortical cataracts. With this information, we also highlight fundamental gaps in the knowledge that could help to inform new avenues of research if effective anti-diabetic cataract therapies are to be developed in the future.

Replacing Animal Testing with Stem Cell-Organoids : Advantages and Limitations

Various groups including animal protection organizations, medical organizations, research centers, and even federal agencies such as the U.S. Food and Drug Administration, are working to minimize animal use in scientific experiments. This movement primarily stems from animal welfare and ethical concerns. However, recent advances in technology and new studies in medicine have contributed to an increase in animal experiments throughout the years. With the rapid increase in animal testing, concerns arise including ethical issues, high cost, complex procedures, and potential inaccuracies.Alternative solutions have recently been investigated to address the problems of animal testing. Some of these technologies are related to stem cell technologies, such as organ-on-a-chip, organoids, and induced pluripotent stem cell models. The aim of the review is to focus on stem cell related methodologies, such as organoids, that can serve as an alternative to animal testing and discuss its advantages and limitations, alongside regulatory considerations.Although stem cell related methodologies has shortcomings, it has potential to replace animal testing. Achieving this requires further research on stem cells, with potential societal and technological benefits.

Untangling the genetics of beta cell dysfunction and death in type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is a complex multi-system disease which arises from both environmental and genetic factors, resulting in the destruction of insulin-producing pancreatic beta cells. Over the past two decades, human genetic studies have provided new insight into the etiology of T1D, including an appreciation for the role of beta cells in their own demise.

SCOPE OF REVIEW

Here, we outline models supported by human genetic data for the role of beta cell dysfunction and death in T1D. We highlight the importance of strong evidence linking T1D genetic associations to bona fide candidate genes for mechanistic and therapeutic consideration. To guide rigorous interpretation of genetic associations, we describe molecular profiling approaches, genomic resources, and disease models that may be used to construct variant-to-gene links and to investigate candidate genes and their role in T1D.

MAJOR CONCLUSIONS

We profile advances in understanding the genetic causes of beta cell dysfunction and death at individual T1D risk loci. We discuss how genetic risk prediction models can be used to address disease heterogeneity. Further, we present areas where investment will be critical for the future use of genetics to address open questions in the development of new treatment and prevention strategies for T1D.

Mangiferin Induces Post-Implant Osteointegration in Male Diabetic Rats

Background and Objectives: Hyperglycemia is known to undermine the osteointegration process of implants. In this study, the effects of mangiferin (MF) on the post-implant osteointegration process in a type-II diabetes model were investigated molecularly and morphologically. Materials and Methods: Sprague Dawley male rats were divided into three groups: control, diabetes, and diabetes + MF. All animals were implanted in their tibia bones on day 0. At the end of the 3-month experimental period, the animals' blood and the implant area were isolated. Biochemical measurements were performed on blood samples and micro-CT, qRT-PCR, histological, and immunohistochemical measurements were performed on tibia samples. Results: MF significantly improved the increased glucose, triglyceride-VLDL levels, and liver enzymes due to diabetes. By administering MF to diabetic rats, the osteointegration percentage and bone volume increased while porosity decreased. DKK1 and BMP-2 mRNA expressions and OPN, OCN, and OSN mRNA-protein expressions increased by MF administration in diabetic rats. Additionally, while osteoblast and osteoid surface areas increased with MF, osteoclast and eroded surface areas decreased. Conclusions: The findings of our study indicate that MF will be beneficial to the bone-repairing process and osteointegration, which are impaired by type-II diabetes.

Semaglutide Attenuates Anxious and Depressive-Like Behaviors and Reverses the Cognitive Impairment in a Type 2 Diabetes Mellitus Mouse Model Via the Microbiota-Gut-Brain Axis

Newly conducted research suggests that metabolic disorders, like diabetes and obesity, play a significant role as risk factors for psychiatric disorders. This connection presents a potential avenue for creating novel antidepressant medications by repurposing drugs originally developed to address antidiabetic conditions. Earlier investigations have shown that GLP-1 (Glucagon-like Peptide-1) analogs exhibit neuroprotective qualities in various models of neurological diseases, encompassing conditions such as Alzheimer's disease, Parkinson's disease, and stroke. Moreover, GLP-1 analogs have demonstrated the capability to enhance neurogenesis, a process recognized for its significance in memory formation and the cognitive and emotional aspects of information processing. Nonetheless, whether semaglutide holds efficacy as both an antidepressant and anxiolytic agent remains uncertain. To address this, our study focused on a mouse model of depression linked to type 2 diabetes induced by a High Fat Diet (HFD). In this model, we administered semaglutide (0.05 mg/Kg intraperitoneally) on a weekly basis to evaluate its potential as a therapeutic option for depression and anxiety. Diabetic mice had higher blood glucose, lipidic profile, and insulin resistance. Moreover, mice fed HFD showed higher serum interleukin (IL)-1β and lipopolysaccharide (LPS) associated with impaired humor and cognition. The analysis of behavioral responses revealed that the administration of semaglutide effectively mitigated depressive- and anxiety-like behaviors, concurrently demonstrating an enhancement in cognitive function. Additionally, semaglutide treatment protected synaptic plasticity and reversed the hippocampal neuroinflammation induced by HFD fed, improving activation of the insulin pathway, demonstrating the protective effects of semaglutide. We also found that semaglutide treatment decreased astrogliosis and microgliosis in the dentate gyrus region of the hippocampus. In addition, semaglutide prevented the DM2-induced impairments of pro-opiomelanocortin (POMC), and G-protein-coupled receptor 43 (GPR43) and simultaneously increased the NeuN + and Glucagon-like Peptide-1 receptor (GLP-1R+) neurons in the hippocampus. Our data also showed that semaglutide increased the serotonin (5-HT) and serotonin transporter (5-HTT) and glutamatergic receptors in the hippocampus. At last, semaglutide changed the gut microbiota profile (increasing Bacterioidetes, Bacteroides acidifaciens, and Blautia coccoides) and decreased leaky gut, improving the gut-brain axis. Taken together, semaglutide has the potential to act as a therapeutic tool for depression and anxiety.

Enteric neuroprotection-A matter of balancing redox potentials, limiting inflammation, and boosting resilience

The enteric nervous system (ENS) orchestrates intricate and autonomous functions throughout the gastrointestinal (GI) tract. Disruptions in ENS function are associated GI disorders. This mini review focuses on the past decade's research, utilizing rodent models, with an emphasis on protecting enteric neurons from loss. The review specifically looks at efforts to reduce oxidative stress, limit inflammation, and enhance neuronal resilience. Protective interventions including administration of antioxidants and compounds targeting cellular redox buffer systems, are evaluated for their effectiveness in preventing loss of enteric neurons in the ischemia-reperfusion model and streptozotocin-induced diabetes model. Interventions such as engrafting mesenchymal stem cells and targeting inflammatory signaling pathways in enteric neurons and glial cells are evaluated in inflammatory bowel disease models including the Winnie mouse, DSS-, and DNBS/TNBS-induced colitis models. The review also touches upon neuronal resilience, particularly in the context of Parkinson's disease models. Including estrogen's neuroprotective role, and the influence of metal ions on enteric neuronal protection. Understanding the dynamic interplay within the ENS and its role in disease pathogenesis holds promise for developing targeted therapies to effectively manage and treat various GI ailments.

Cilostazol Ameliorates Motor Dysfunction and Schwann Cell Impairment in Streptozotocin-Induced Diabetic Rats

This study investigated the effects of cilostazol on motor dysfunction, spinal motor neuron abnormalities, and schwannopathy in rats with diabetes. Diabetes mellitus (DM) was induced in rats via femoral intravenous streptozotocin (STZ) injection (60 mg/kg). After successful DM induction, cilostazol was administered on day 15 via oral gavage (100 mg/kg/day) for 6 weeks until sacrifice. Behavioral assays, including motor function, were performed weekly. The sciatic nerve, L5 spinal cord, and spinal ventral root were collected to evaluate the expression of the glial fibrillary acidic protein (GFAP), myelin protein zero (P0), and choline acetyltransferase (ChAT) by immunofluorescence and Western blotting. DM rats displayed decreased running speeds, running distances, and toe spread but increased foot pressure. In addition, loss of non-myelinating Schwann cells and myelin sheaths was observed in the sciatic nerve and L5 spinal ventral root. Reduced numbers of motor neurons were also found in the L5 spinal ventral horn. Cilostazol administration significantly potentiated running speed and distance; increased hind paw toe spread; and decreased foot pressure. In the sciatic nerve and L5 spinal ventral root, cilostazol treatment significantly improved non-myelinated Schwann cells and increased myelin mass. ChAT expression in motor neurons in the spinal ventral horn was improved, but not significantly. Cilostazol administration may protect sensorimotor function in diabetic rats.

Global trends in publications regarding macrophages-related diabetic foot ulcers in the last two decades

BACKGROUND

Diabetic foot ulcers (DFUs) are one of the most severe and popular complications of diabetes. The persistent non-healing of DFUs is the leading cause of ampu-tation, which causes significant mental and financial stress to patients and their families. Macrophages are critical cells in wound healing and perform essential roles in all phases of wound healing. However, no studies have been carried out to systematically illustrate this area from a scientometric point of view. Although there have been some bibliometric studies on diabetes, reports focusing on the investigation of macrophages in DFUs are lacking.

AIM

To perform a bibliometric analysis to systematically assess the current state of research on macrophage-related DFUs.

METHODS

The publications of macrophage-related DFUs from January 1, 2004, to December 31, 2023, were retrieved from the Web of Science Core Collection on January 9, 2024. Four different analytical tools: VOSviewer (v1.6.19), CiteSpace (v6.2.R4), HistCite (v12.03.07), and Excel 2021 were used for the scientometric research.

RESULTS

A total of 330 articles on macrophage-related DFUs were retrieved. The most published countries, institutions, journals, and authors in this field were China, Shanghai Jiao Tong University of China, Wound Repair and Regeneration, and Aristidis Veves. Through the analysis of keyword co-occurrence networks, historical direct citation networks, thematic maps, and trend topics maps, we synthesized the prevailing research hotspots and emerging trends in this field.

CONCLUSION

Our bibliometric analysis provides a comprehensive overview of macrophage-related DFUs research and insights into promising upcoming research.

Guidelines for assessing maternal cardiovascular physiology during pregnancy and postpartum

Maternal mortality rates are at an all-time high across the world and are set to increase in subsequent years. Cardiovascular disease is the leading cause of death during pregnancy and postpartum, especially in the United States. Therefore, understanding the physiological changes in the cardiovascular system during normal pregnancy is necessary to understand disease-related pathology. Significant systemic and cardiovascular physiological changes occur during pregnancy that are essential for supporting the maternal-fetal dyad. The physiological impact of pregnancy on the cardiovascular system has been examined in both experimental animal models and in humans. However, there is a continued need in this field of study to provide increased rigor and reproducibility. Therefore, these guidelines aim to provide information regarding best practices and recommendations to accurately and rigorously measure cardiovascular physiology during normal and cardiovascular disease-complicated pregnancies in human and animal models.

Selenium Species in Diabetes Mellitus Type 2

Selenium is an important trace element for humans and animals as it plays a key role in several major metabolic pathways. Several studies were conducted to better understand the role of selenium against diabetes mellitus (DM), particularly type 2 (T2DM), but the obtained conclusions are contradictory. A simple linear relationship does not exist between the risk of T2DM and selenium levels but is best represented in a dose-dependent manner, getting often the U-graph. This relation also depends on selenium chemical forms that are present in a diet or supplements. Both too low and too high selenium intakes could increase the risk of diabetes. Moreover, the baseline status of Se should be taken into consideration to avoid over-supplementation. The focus of this brief overview is to report the recent updates concerning selenium participation in diabetes mellitus.

Antidiabetic effect of combined extract of Coccinia grandis and Blumea balsamifera on streptozotocin-nicotinamide induced diabetic rats

BACKGROUND

Coccinia grandis and Blumea balsamifera are two medicinal plants that have been known to have good antidiabetic properties. Combining these two plant extracts may generate a greater effect that can increase efficacy and decrease the dose.

OBJECTIVE

This research investigated the antidiabetic activity of the combination of C. grandis and B. balsamifera leaves extracts on experimental diabetic rats.

MATERIALS AND METHODS

The dried leaves of C. grandis and B. balsamifera were powdered and macerated with ethanol 70% (v/v). A diabetic condition in male Wistar albino rats was generated by intraperitoneal injection of a single dose of streptozotocin (65 mg/kg) followed by nicotinamide (110 mg/kg). Diabetes-confirmed rats were then given glibenclamide (4.5 mg/kg), C. grandis extract (300 mg/kg), B. balsamifera extract (150 mg/kg), and the combined extracts with a dose ratio of 1:1, 1:3, and 3:1. The treatment was performed for 28 days and fasting blood glucose was tested once a week. The pancreas and liver organs were taken on day 29 for antioxidant, histological, and immunohistochemical assessment.

RESULTS

Among all the extracts, the combined extract with a ratio of 1:3 showed the greatest glucose lowering effect. This combination also lowered malondialdehyde levels while increasing superoxide dismutase and catalase levels in the pancreas and liver organs. Histological examination showed this combination regenerated the islet of Langerhans. It also increased pancreatic insulin expression in immunohistochemical evaluation.

CONCLUSION

This study revealed that the combined extracts of C. grandis and B. balsamifera exhibited enhanced antidiabetic activity via ameliorating oxidative stress, regenerating β-cells, and increasing insulin expression.

A comprehensive in-vitro/in-vivo screening toolbox for the elucidation of glucose homeostasis modulating properties of plant extracts (from roots) and its bioactives

Plant extracts are increasingly recognized for their potential in modulating (postprandial) blood glucose levels. In this context, root extracts are of particular interest due to their high concentrations and often unique spectrum of plant bioactives. To identify new plant species with potential glucose-lowering activity, simple and robust methodologies are often required. For this narrative review, literature was sourced from scientific databases (primarily PubMed) in the period from June 2022 to January 2024. The regulatory targets of glucose homeostasis that could be modulated by bioactive plant compounds were used as search terms, either alone or in combination with the keyword "root extract". As a result, we present a comprehensive methodological toolbox for studying the glucose homeostasis modulating properties of plant extracts and its constituents. The described assays encompass in-vitro investigations involving enzyme inhibition (α-amylase, α-glucosidase, dipeptidyl peptidase 4), assessment of sodium-dependent glucose transporter 1 activity, and evaluation of glucose transporter 4 translocation. Furthermore, we describe a patch-clamp technique to assess the impact of extracts on KATP channels. While validating in-vitro findings in living organisms is imperative, we introduce two screenable in-vivo models (the hen's egg test and Drosophila melanogaster). Given that evaluation of the bioactivity of plant extracts in rodents and humans represents the current gold standard, we include approaches addressing this aspect. In summary, this review offers a systematic guide for screening plant extracts regarding their influence on key regulatory elements of glucose homeostasis, culminating in the assessment of their potential efficacy in-vivo. Moreover, application of the presented toolbox might contribute to further close the knowledge gap on the precise mechanisms of action of plant-derived compounds.

Adiposity in mares induces insulin dysregulation and mitochondrial dysfunction which can be mitigated by nutritional intervention

Obesity is a complex disease associated with augmented risk of metabolic disorder development and cellular dysfunction in various species. The goal of the present study was to investigate the impacts of obesity on the metabolic health of old mares as well as test the ability of diet supplementation with either a complex blend of nutrients designed to improve equine metabolism and gastrointestinal health or L-carnitine alone to mitigate negative effects of obesity. Mares (n = 19, 17.9 ± 3.7 years) were placed into one of three group: normal-weight (NW, n = 6), obese (OB, n = 7) or obese fed a complex diet supplement for 12 weeks (OBD, n = 6). After 12 weeks and completion of sample collections, OB mares received L-carnitine alone for an additional 6 weeks. Obesity in mares was significantly associated with insulin dysregulation, reduced muscle mitochondrial function, and decreased skeletal muscle oxidative capacity with greater ROS production when compared to NW. Obese mares fed the complex diet supplement had better insulin sensivity, greater cell lipid metabolism, and higher muscle oxidative capacity with reduced ROS production than OB. L-carnitine supplementation alone did not significantly alter insulin signaling, but improved lipid metabolism and muscle oxidative capacity with reduced ROS. In conclusion, obesity is associated with insulin dysregulation and altered skeletal muscle metabolism in older mares. However, dietary interventions are an effective strategy to improve metabolic status and skeletal muscle mitochondrial function in older mares.

Evaluating the Antihyperalgesic Potential of Sildenafil-Metformin Combination and Its Impact on Biochemical Markers in Alloxan-Induced Diabetic Neuropathy in Rats

(1) Background: Globally, about 600 million people are afflicted with diabetes, and one of its most prevalent complications is neuropathy, a debilitating condition. At the present time, the exploration of novel therapies for alleviating diabetic-neuropathy-associated pain is genuinely captivating, considering that current therapeutic options are characterized by poor efficacy and significant risk of side effects. In the current research, we evaluated the antihyperalgesic effect the sildenafil (phosphodiesterase-5 inhibitor)-metformin (antihyperglycemic agent) combination and its impact on biochemical markers in alloxan-induced diabetic neuropathy in rats. (2) Methods: This study involved a cohort of 70 diabetic rats and 10 non-diabetic rats. Diabetic neuropathy was induced by a single dose of 130 mg/kg alloxan. The rats were submitted to thermal stimulus test using a hot-cold plate and to tactile stimulus test using von Frey filaments. Moreover, at the end of the experiment, the animals were sacrificed and their brains and livers were collected to investigate the impact of this combination on TNF-α, IL-6, nitrites and thiols levels. (3) Results: The results demonstrated that all sildenafil-metformin combinations decreased the pain sensitivity in the von Frey test, hot plate test and cold plate test. Furthermore, alterations in nitrites and thiols concentrations and pro-inflammatory cytokines (specifically TNF-α and IL-6) were noted following a 15-day regimen of various sildenafil-metformin combinations. (4) Conclusions: The combination of sildenafil and metformin has a synergistic effect on alleviating pain in alloxan-induced diabetic neuropathy rats. Additionally, the combination effectively decreased inflammation, inhibited the rise in NOS activity, and provided protection against glutathione depletion.

A Novel Diabetic Arthritic Model in Rats Induced by Streptozotocin, High-Fat Diet, and Complete Freund's Adjuvant

Introduction

Ankle arthrodesis is one of the treatments of choice, particularly in late-stage and unstable diabetic Charcot arthropathy. Unfortunately, poor healing capacity might play a role in the high nonunion rate (10-40%). The advancement in regenerative medicine opens a new horizon for enhancing fusion after ankle arthrodesis in patients with poor healing capacity. However, a suitable small animal model is warranted to study the effectivity of these regenerative medicine approaches. Streptozotocin (STZ)-induced diabetes models and adjuvant-induced arthritis models with complete Freund's adjuvant are two established models. However, no study has combined those two models to make a diabetic arthritic model that more closely resembles the condition in Charcot arthropathy.

Methods

Twenty male Sprague-Dawley rats were assigned into five groups, consisting of one control group, and four diabetic groups which were induced by STZ injection and a high-fat diet. Among these diabetic rats, two groups received complete Freund's adjuvant (CFA) injections to the left ankle of the hind limb. The control group, one of the diabetic-only groups, and one of the arthritic-diabetic-induced groups were euthanized at 4 weeks after STZ induction, and the remainder were euthanized 6 weeks after STZ induction. Clinical, radiological, and histological examinations were then compared in all five groups.

Results

Diabetic status was successfully achieved in the model, which was maintained until the completion of the study. The CFA-induced ankles were significantly larger than the contralateral ankles in all groups (p<0.05). Histopathological evaluation confirmed arthritic changes in the CFA-induced group with less variability after 4 weeks of arthritis induction.

Conclusion

This rat model of arthritic diabetic mimics the progressive and chronic nature of Charcot arthropathy in humans. This model can be further use to study treatments that might enhance the fusion rate in ankle arthrodesis in healing-defective patients such as those with diabetes.

Level of Clinical Evidence

5.

Effects of paradoxical sleep deprivation on oxidative parameters in the serum and brain of mice submitted to the animal model of hyperglycemia

The present study aimed to investigate the effects of paradoxical sleep deprivation (PSD) on behavioral and oxidative stress parameters in the brain and serum of mice submitted to the animal model of hyperglycemia induced by alloxan, mimicking the main symptom of diabetes mellitus (DM). Adults C57BL/6 male and female mice received an injection of alloxan, and ten days later, the animals were submitted to the PSD for 36 h. The animals' behavioral parameters were evaluated in the open-field test. Oxidative stress parameters [Diacetyldichlorofluorescein (DCF), Thiobarbituric acid reactive substances (TBARS), Superoxide dismutase (SOD), and Glutathione] were assessed in the frontal cortex, hippocampus, striatum, and serum. The PSD increased the male and female mice locomotion, but the alloxan's pre-administration prevented the PSD-induced hyperactivity. In addition, the male mice receiving alloxan and submitted to the PSD had elevated latency time in the first quadrant and the number of fecal boli, demonstrating increased anxiety-like behavior. The HPA-axis was hyperactivating in male and female mice pre-administered alloxan and/or PSD-submitted animals. The oxidative stress parameters were also increased in the serum of the animals administered alloxan and/or sleep-deprived mice. Despite alloxan or PSD leading to behavioral or biochemical alterations, the one did not potentiate the other in mice. However, more studies are necessary to identify the link between sleep and hyperglycemia.

The effect of Andaliman (Zanthoxylum acanthopodium DC.) fruit extracted with ethanol on TNF-α and TRPA-1 levels in type II diabetes-induced mice

Objective

The present study investigated the effects of Andaliman fruit extract on tumor necrosis factor-alpha (TNF-α) and transient receptor potential ankyrin-1 (TRPA-1) levels in type 2 diabetes mellitus (T2DM) mouse models induced with streptozocin (STZ) and a high-fat diet (HFD).

Materials and Methods

In this research, mice were allocated into six distinct groups: normal, negative control (HFD and STZ), positive control (metformin, HFD, and STZ), and three treatment groups (HFD, STZ, and Andaliman extract at varying dosages of 100, 300, and 500 mg/kg, respectively). Body weight and blood glucose levels (BGLs) were recorded at weeks 1 (baseline), 8, 12, and 16. The levels of TNF-α and TRPA-1 were measured during the 16th week.

Results

Phytochemical screening of the Andaliman extract revealed the presence of flavonoids, alkaloids, tannins, saponins, and glycosides. The one-way ANOVA revealed significantly elevated BGL at week 16 in the negative control group in comparison to the other groups (p < 0.05). The Kruskal-Wallis test followed by Bonferroni-corrected pairwise comparisons showed that the negative control had significantly higher TNF-α levels than the Andaliman-groups (z = 22.11, p < 0.01). TRPA-1 was significantly higher in the negative control group compared to the treatment groups (p < 0.05). Furthermore, Spearman's rho analysis revealed a statistically significant positive association between BGL and both TNF-α and TRPA-1, as well as between TNF-α and TRPA.

Conclusion

Andaliman extract potentially serves as a therapy for diabetic neuropathy in T2DM by lowering BGL and inhibiting the expression of TNF-α and TRPA-1.