A Comprehensive Review of Neuronal Changes in Diabetics

Dietary menhaden fish oil supplementation suppresses lipopolysaccharide-induced neuroinflammation and cognitive impairment in diabetic rats

CONTEXT

Menhaden fish oil (FO) is widely recognized for inhibiting neuroinflammatory responses and preserving brain function. Nevertheless, the mechanisms of FO influencing brain cognitive function in diabetic states remain unclear.

OBJECTIVE

This study examines the potential role of FO in suppressing LPS-induced neuroinflammation and cognitive impairment in diabetic animals (DA).

MATERIALS AND METHODS

Thirty male Wistar rats were divided into 5 groups: i) DA received LPS induction (DA-LPS); ii) DA received LPS induction and 1 g/kg FO (DA-LPS-1FO); iii) DA received LPS induction and 3 g/kg FO (DA-LPS-3FO); iv) animals received normal saline and 3 g/kg FO (NS-3FO) and v) control animals received normal saline (CTRL). Y-maze test was used to measure cognitive performance, while brain samples were collected for inflammatory markers and morphological analysis.

RESULTS

DA received LPS induction, and 1 or 3 g/kg FO significantly inhibited hyperglycaemia and brain inflammation, as evidenced by lowered levels of pro-inflammatory mediators. Additionally, both DA-LPS-1FO and DA-LPS-3FO groups exhibited a notable reduction in neuronal damage and glial cell migration compared to the other groups. These results were correlated with the increasing number of entries and time spent in the novel arm of the Y-maze test.

DISCUSSION AND CONCLUSION

This study indicates that supplementation of menhaden FO inhibits the LPS signaling pathway and protects against neuroinflammation, consequently maintaining cognitive performance in diabetic animals. Thus, the current study suggested that fish oil may be effective as a supporting therapy option for diabetes to avoid diabetes-cognitive impairment.

Diabetic Neuropathy: Pathophysiology Review

PURPOSE OF REVIEW

Diabetic neuropathy is a debilitating complication of diabetes mellitus that affects millions of individuals worldwide. It is characterized by nerve damage resulting from prolonged exposure to high blood glucose levels. Diabetic neuropathy may cause a range of symptoms, including pain, numbness, muscle weakness, autonomic dysfunction, and foot ulcers, potentially causing significant impairment to the quality of life for those affected. This review article aims to provide a comprehensive overview of the pathophysiology of diabetic neuropathy. The etiology of diabetic neuropathy will be discussed, including risk factors, predisposing conditions, and an overview of the complex interplay between hyperglycemia, metabolic dysregulation, and nerve damage. Additionally, we will explore the molecular mechanisms and pathways of diabetic neuropathy, including the impact of hyperglycemia on nerve function, abnormalities in glucose metabolism, the role of advanced glycation end products (AGEs), and inflammatory and immune-mediated processes. We will provide an overview of the various nerve fibers affected by diabetic neuropathy and explore the common symptoms and complications associated with diabetic neuropathy in the pain medicine field.

RECENT FINDINGS

This review highlights advances in understanding the pathophysiology of diabetic neuropathy as well as reviews potential novel therapeutic strategies and promising areas for future research. In conclusion, this review article aims to shed light on the pathophysiology of diabetic neuropathy, its far-reaching consequences, and the evolving strategies for prevention and management. In understanding the mechanisms of diabetic neuropathy and the ongoing research in this area, healthcare professionals can better serve patients with diabetes, ultimately improving well-being and reducing complications.

Systematic review and meta-analysis of the effects of exercise on cognitive impairment and neuroprotective mechanisms in diabetes mellitus animal models

This study aims to assess the effects of exercise on cognitive impairment behavioral performance and neuroprotective mechanisms in diabetes mellitus (DM) animal models. PubMed, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang Database, VIP Database (VIP), and China Biomedical Literature Database (CBM) were systematically searched for studies investigating the impact of exercise on cognitive impairment in animal models of diabetes mellitus (DM) from the inception of these databases through July 2023. Rigorous quality assessments were conducted on the included literature. Primary outcome measures comprised fasting blood glucose (FBG) levels and performance in the Morris water maze test, while secondary outcomes focused on mechanisms related to neuroprotection. Statistical analysis of outcome data was conducted using RevMan 5.3 and R software. A total of 17 studies were included, encompassing 399 animals. The results of the meta-analysis of primary outcome measures revealed that, compared to the control group, exercise effectively reduced fasting blood glucose (FBG) levels in diabetic animal models. In the Morris water maze experiment, exercise also significantly decreased the escape latency of diabetic animal models, increased the number of platform crossings, improved the percentage of time spent in the target quadrant, extended the time spent in the target quadrant, and enhanced swimming speed. Meta-analysis of secondary outcome measures indicated that exercise effectively reduced Aβ deposition, attenuated oxidative stress, enhanced synaptic function, suppressed cellular apoptosis and neuroinflammation, and promoted neurogenesis. Exercise represents a promising non-pharmacological therapy with a positive impact on diabetes-related cognitive function and neuroprotection. Moreover, this study provides a theoretical foundation for further preclinical and clinical trials.

The circadian rhythm: an influential soundtrack in the diabetes story

Type 2 Diabetes Mellitus (T2DM) has been the main category of metabolic diseases in recent years due to changes in lifestyle and environmental conditions such as diet and physical activity. On the other hand, the circadian rhythm is one of the most significant biological pathways in humans and other mammals, which is affected by light, sleep, and human activity. However, this cycle is controlled via complicated cellular pathways with feedback loops. It is widely known that changes in the circadian rhythm can alter some metabolic pathways of body cells and could affect the treatment process, particularly for metabolic diseases like T2DM. The aim of this study is to explore the importance of the circadian rhythm in the occurrence of T2DM via reviewing the metabolic pathways involved, their relationship with the circadian rhythm from two perspectives, lifestyle and molecular pathways, and their effect on T2DM pathophysiology. These impacts have been demonstrated in a variety of studies and led to the development of approaches such as time-restricted feeding, chronotherapy (time-specific therapies), and circadian molecule stabilizers.

Plasma-Lyte-148 Versus Normal Saline 0.9% in Diabetic Ketoacidosis Management: A Review

Diabetic ketoacidosis (DKA) is a critical complication of diabetes mellitus characterized by hyperglycemia, ketonemia, circulatory collapse, hypokalemia, and metabolic acidosis. The therapeutic management of DKA includes vigilant fluid resuscitation to address dehydration and electrolyte imbalances and restore hemodynamic stability. The choice of fluid, either isotonic saline or a balanced electrolyte solution like Plasma-Lyte 148 (PL), is pivotal in the clinical outcomes of DKA patients. Recent studies have compared the effectiveness of these fluid solutions in DKA management, focusing on different clinical outcomes such as the resolution of metabolic acidosis, electrolyte imbalances, the incidence of acute kidney injury, and length of hospital stay. This review examines the literature comparing isotonic saline and balanced electrolyte solutions for fluid resuscitation in DKA, analyzing the associated clinical outcomes. Through synthesizing research findings, this review aims to elucidate the efficacy and potential advantages of utilizing PL as an alternative to traditional isotonic saline for fluid resuscitation in treating DKA. This would further facilitate evidence-based decision-making among healthcare professionals and contribute to optimizing DKA management strategies. Understanding the intricacies and implications of fluid resuscitation is crucial, given its profound impact on patient outcomes in DKA management.

O-GlcNAcylation is crucial for sympathetic neuron development, maintenance, functionality and contributes to peripheral neuropathy

O-GlcNAcylation is a post-translational modification (PTM) that regulates a wide range of cellular functions and has been associated with multiple metabolic diseases in various organs. The sympathetic nervous system (SNS) is the efferent portion of the autonomic nervous system that regulates metabolism of almost all organs in the body. How much the development and functionality of the SNS are influenced by O-GlcNAcylation, as well as how such regulation could contribute to sympathetic neuron (symN)-related neuropathy in diseased states, remains unknown. Here, we assessed the level of protein O-GlcNAcylation at various stages of symN development, using a human pluripotent stem cell (hPSC)-based symN differentiation paradigm. We found that pharmacological disruption of O-GlcNAcylation impaired both the growth and survival of hPSC-derived symNs. In the high glucose condition that mimics hyperglycemia, hPSC-derived symNs were hyperactive, and their regenerative capacity was impaired, which resembled typical neuronal defects in patients and animal models of diabetes mellitus. Using this model of sympathetic neuropathy, we discovered that O-GlcNAcylation increased in symNs under high glucose, which lead to hyperactivity. Pharmacological inhibition of O-GlcNAcylation rescued high glucose-induced symN hyperactivity and cell stress. This framework provides the first insight into the roles of O-GlcNAcylation in both healthy and diseased human symNs and may be used as a platform for therapeutic studies.

Neurological Features and Their Association With Gender in Diabetes Mellitus Patients

Introduction Understanding the wide range of clinical signs and symptoms associated with diabetes mellitus (DM) is crucial because people with DM are frequently misdiagnosed, given incorrect care, or poorly controlled. Therefore, the purpose of this study was to evaluate the neurological symptoms associated with type 1 and type 2 DM patients with respect to patient gender. Methods This was a cross-sectional multicenter study that was conducted at different hospitals using a non-probability sampling method. The duration of the study was eight months, from January 2022 to August 2022. The study involved 525 type 1 and type 2 DM patients with an age range from 35 to 70 years. Demographic details such as age, gender, socioeconomic status, past medical history, presence of comorbidities, type, and duration of DM, and neurological features were recorded as frequencies and percentages. A Chi-square test was used to determine the association between neurological symptoms associated with type 1 and type 2 DM and gender. Results The study findings showed that of 525 diabetic patients, 210 (40.0%) were females and 315 (60.0%) were males. The mean male and female mean ages were 57.36±14.99 and 50.52±14.8 years, respectively, with a significant difference with respect to gender (p<0.001). The prevalence of neurological manifestations showed that irritability or mood swings were reported by most of the male 216 (68.6%) and 163 (77.6%) female diabetic patients, with a significant association noticed (p=0.022). Moreover, a significant association was observed between both genders in terms of swelling of feet, ankles, hands, and eyes (p=0.042), confusion or difficulty in concentration (p=0.040), burning pain in feet or legs (p=0.012), and muscular pain or cramps in legs or feet (p=0.016).  Conclusion This study concluded that the prevalence of neurological manifestations was high among diabetic patients. Most of the neurological symptoms were significantly more pronounced in female diabetic patients. Moreover, most of the neurological symptoms were associated with the type (type 2 DM) and duration of DM. The presence of hypertension, dyslipidemia, and smoking also influenced some neurological manifestations.

Neuroprotective Effect of Wharton's Jelly-Derived Mesenchymal Stem Cell-Conditioned Medium (WJMSC-CM) on Diabetes-Associated Cognitive Impairment by Improving Oxidative Stress, Neuroinflammation, and Apoptosis

According to strong evidence, diabetes mellitus increases the risk of cognitive impairment. Mesenchymal stem cells have been shown to be potential therapeutic agents for neurological disorders. In the current study, we aimed to examine the effects of Wharton's jelly-derived mesenchymal stem cell-conditioned medium (WJMSC-CM) on learning and memory, oxidative stress, apoptosis, and histological changes in the hippocampus of diabetic rats. Randomly, 35 male Sprague Dawley rats weighing 260-300 g were allocated into five groups: control, diabetes, and three diabetic groups treated with insulin, WJMSC-CM, and DMEM. The injections of insulin (3 U/day, S.C.) and WJMSC-CM (10 mg/week, I.P.) were done for 60 days. The Morris water maze and open field were used to measure cognition and anxiety-like behaviors. Colorimetric assays were used to determine hippocampus glutathione (GSH), malondialdehyde (MDA) levels, and antioxidant enzyme activity. The histopathological evaluation of the hippocampus was performed by Nissl staining. The expression levels of Bax, Bcl-2, BDNF, and TNF-α were detected by real-time polymerase chain reaction (RT-PCR). According to our findings, WJMSC-CM significantly reduced and increased blood glucose and insulin levels, respectively. Enhanced cognition and improved anxiety-like behavior were also found in WJMSC-CM-treated diabetic rats. In addition, WJMSC-CM treatment reduced oxidative stress by lowering MDA and elevating GSH and antioxidant enzyme activity. Reduced TNF-α and enhanced Bcl-2 gene expression levels and elevated neuronal and nonneuronal (astrocytes and oligodendrocytes) cells were detected in the hippocampus of WJMSC-CM-treated diabetic rats. In conclusion, WJMSC-CM alleviated diabetes-related cognitive impairment by reducing oxidative stress, neuroinflammation, and apoptosis in diabetic rats.

Exploration of Lipid-Based Nanocarriers as Drug Delivery Systems in Diabetic Foot Ulcer

Diabetes mellitus is a chronic manifestation characterized by high levels of glucose in the blood resulting in several complications including diabetic wounds and ulcers, which predominantly require a longer duration of treatment and adversely affect the quality of life of the patients. Nanotechnology-based therapeutics (both intrinsic and extrinsic types) have emerged as a promising treatment in diabetic foot ulcer/chronic wounds owing to their unique characteristics and specific functional properties. In this review, we have focused on the significance of the use of lipids in the healing of diabetic ulcers, their interaction with the injured skin, and recent trends in lipid-based nanocarriers for the healing of diabetic wounds. Lipid nanocarriers are also being investigated for gene therapy in diabetic wound healing to encapsulate nucleic acids such as siRNA and miRNA, which could silence the expression of inflammatory cytokines overexpressed in chronic wounds. Additionally, these are also being explored for encapsulating proteins, peptides, growth factors, and other biological genetic material as therapeutic agents. Lipid-based nanocarriers encompassing a wide variety of carriers such as liposomes, niosomes, ethosomes, solid lipid nanoparticles, and lipidoid nanoparticles that are explored for the treatment of foot ulcers supplemented with relevant research studies have been discussed in the present review. Lipid-based nanodrug delivery systems have demonstrated promising wound healing potential, particularly in diabetic conditions due to the enhanced efficacy of the entrapped active molecules.

Neuroprotective Effect of 3',4'-Dihydroxyphenylglycol in Type-1-like Diabetic Rats-Influence of the Hydroxytyrosol/3',4'-dihydroxyphenylglycol Ratio

The aim of this study was to assess the possible neuroprotective effect of 3′,4′-dihydroxyphenylglycol (DHPG), a polyphenol from extra virgin olive oil (EVOO), in an experimental model of diabetes and whether this effect is modified by the presence of another EVOO polyphenol, hydroxytyrosol (HT). The neuroprotective effect was assessed in a hypoxia–reoxygenation model in brain slices and by quantifying retinal nerve cells. The animals were distributed as follows: (1) normoglycemic rats (NDR), (2) diabetic rats (DR), (3) DR treated with HT (5 mg/kg/day p.o.), (4) DR treated with DHPG (0.5 mg/kg/day), or (5) with 1 mg/kg/day, (6) DR treated with HT plus DHPG 0.5 mg/kg/day, or (7) HT plus 1 mg/kg/day p.o. DHPG. Diabetic animals presented higher levels of oxidative stress variables and lower numbers of neuronal cells in retinal tissue. The administration of DHPG or HT reduced most of the oxidative stress variables and brain lactate dehydrogenase efflux (LDH) as an indirect index of cellular death and also reduced the loss of retinal cells. The association of DHPG+HT in the same proportions, as found in EVOO, improved the neuroprotective and antioxidant effects of both polyphenols.