Effects and Underlying Mechanisms of Bioactive Compounds on Type 2 Diabetes Mellitus and Alzheimer's Disease

Single oral administration of quercetin glycosides prevented acute hyperglycemia by promoting GLUT4 translocation in skeletal muscles through the activation of AMPK in mice

Quercetin is a natural flavonol and has various health beneficial functions. Our pervious study demonstrated that long-term feeding (13 weeks) of quercetin and its glycosides, isoquercitrin, rutin, and enzymatically modified isoquercitrin, which is a mixture of quercetin monoglycoside and its oligoglycosides, prevented hyperglycemia and adiposity in mice fed a high-fat diet but not standard diet. It is, however, unclear whether a single administration of these compounds prevent postprandial hyperglycemia or not. In the present study, we estimated their prevention effect on acute hyperglycemia by an oral glucose tolerance test in ICR mice and investigated its mechanism. It was found that quercetin glycosides, but not the aglycone, suppressed acute hyperglycemia and isoquercitrin showed the strongest effect among the glycosides. As the underlying mechanism, quercetin glycosides promoted translocation of glucose transporter 4 to the plasma membrane of skeletal muscle of mice through phosphorylation of adenosine monophosphate-activated protein kinase and its upstream Ca2+/calmodulin-dependent protein kinase kinase β without activating the insulin- and JAK/STAT-signal pathways. In conclusion, single oral administration of quercetin glycosides prevented a blood sugar spike by promoting glucose transporter 4 translocation through activating the CAMKKβ/AMPK signaling pathway.

Genetics of diabetes

Diabetes mellitus is a complicated disease characterized by a complex interplay of genetic, epigenetic, and environmental variables. It is one of the world's fastest-growing diseases, with 783 million adults expected to be affected by 2045. Devastating macrovascular consequences (cerebrovascular disease, cardiovascular disease, and peripheral vascular disease) and microvascular complications (like retinopathy, nephropathy, and neuropathy) increase mortality, blindness, kidney failure, and overall quality of life in individuals with diabetes. Clinical risk factors and glycemic management alone cannot predict the development of vascular problems; multiple genetic investigations have revealed a clear hereditary component to both diabetes and its related complications. In the twenty-first century, technological advancements (genome-wide association studies, next-generation sequencing, and exome-sequencing) have led to the identification of genetic variants associated with diabetes, however, these variants can only explain a small proportion of the total heritability of the condition. In this review, we address some of the likely explanations for this "missing heritability", for diabetes such as the significance of uncommon variants, gene-environment interactions, and epigenetics. Current discoveries clinical value, management of diabetes, and future research directions are also discussed.

Beneficial Contribution to Glucose Homeostasis by an Agro-Food Waste Product Rich in Abscisic Acid: Results from a Randomized Controlled Trial

The control of glucose homeostasis represents the primary goal for the prevention and management of diabetes and prediabetes. In recent decades, the hypoglycemic hormone abscisic acid (ABA) has attracted considerable interest in the scientific literature. In this regard, the high ABA concentration in immature fruits led us to consider these food matrices as candidates for diabetes control. Therefore, the beneficial efficacy of a nutraceutical formulation based on thinned nectarines (TNs) rich in ABA was tested through a three-month, three-arm, parallel-group, randomized controlled trial (RCT) conducted on sixty-one patients with type 2 diabetes (T2D). After 3 months, both the treatments with low doses of TN (500 mg 3 times/day) and high doses of TN (750 mg 3 times/day) showed a significant reduction in glycemic parameters compared to baseline. Treatment with low doses of TN showed a greater insulin-sparing effect (fasting plasma insulin, FPI: −29.2%, p < 0.05 vs. baseline) compared to the high-dose group (FPI: −16.5%, p < 0.05 vs. baseline). Moreover, a significant correlation between glycemia and ABA plasmatic levels was observed for both intervention groups at baseline and after 3 months. Overall, our data reasonably support TN as a promising and innovative nutraceutical product able to contribute to the management of glucose homeostasis.

Evaluation of Antidiabetic and Antihyperlipidemic Activity of 80% Methanolic Extract of the Root of Solanum incanum Linnaeus (Solanaceae) in Mice

Background

Conventional antidiabetic drugs are linked with a number of contraindications and untoward effects. The root decoction of Solanum incanum L. has traditionally been used to treat diabetes. However, its safety and efficacy have not been scientifically authenticated yet. Hence, the study was conducted in mice to corroborate its antidiabetic potential and safety profile.

Methods

Using normoglycemic, oral glucose-loaded, and streptozotocin-induced diabetic mice models, the hypoglycemic and antihyperglycemic activities of 80% methanolic root extract were investigated. On streptozotocin-induced diabetic mice, the effect of the test extract on diabetic lipid profile and body weight was also investigated. Further, the in vitro α-amylase inhibition activity was assessed.

Results

The test extract was safe at a limit test dose of 2 g/kg. Dose-dependent α-amylase inhibition activity was seen with peak percentage inhibition of 75.95% at 700 μg/mL. In normoglycemic mice, the plant extract showed statistically significant hypoglycemic activity at 200 and 400 mg/kg (P < 0.001) at 6  h and 4 and 6 h of treatment, respectively; in oral glucose-loaded mice, at both the test doses, the glucose level was also significantly dropped at 120 (P < 0.01) and 60 and 120 min (P < 0.001), respectively; whereas, in the third model, the test extract showed significant antihyperglycemic activity at 100 mg/kg (P < 0.05) on the 14^th day and at 200 (P < 0.01) and 400 mg/kg (P < 0.001) on the 7^th and 14^th day of treatment. Similarly, following repeated administration of the test extract at 200 and 400 mg/kg, the body weight was significantly improved on the 14^th day (P < 0.05) and on the 7^th and 14^th day (P < 0.01), respectively, while diabetic dyslipidemia after 14 days (P < 0.05).

Conclusion

The study revealed that the test extract showed promising antihyperglycemic and antihyperlipidemic activity. Thus, the findings back up its use in Ethiopian remedies for diabetes.

Antidiabetic Potential of Plants from the Caribbean Basin

Diabetes mellitus (DM) is a group of metabolic disorders characterized by hyperglycemia, insulin insufficiency or insulin resistance, and many issues, including vascular complications, glycative stress and lipid metabolism dysregulation. Natural products from plants with antihyperglycemic, hypolipidemic, pancreatic protective, antioxidative, and insulin-like properties complement conventional treatments. Throughout this review, we summarize the current status of knowledge of plants from the Caribbean basin traditionally used to manage DM and treat its sequelae. Seven plants were chosen due to their use in Caribbean folk medicine. We summarize the antidiabetic properties of each species, exploring the pharmacological mechanisms related to their antidiabetic effect reported in vitro and in vivo. We propose the Caribbean flora as a source of innovative bioactive phytocompounds to treat and prevent DM and DM-associated complications.

Cardiometabolic Modification of Amyloid Beta in Alzheimer's Disease Pathology

In recent years, several studies have suggested that cardiometabolic disorders, such as diabetes, obesity, hypertension, and dyslipidemia, share strong connections with the onset of neurodegenerative disorders such as Parkinson’s and Alzheimer’s disease (AD). However, establishing a definitive link between medical disorders with coincident pathophysiologies is difficult due to etiological heterogeneity and underlying comorbidities. For this reason, amyloid β (Aβ), a physiological peptide derived from the sequential proteolysis of amyloid precursor protein (APP), serves as a crucial link that bridges the gap between cardiometabolic and neurodegenerative disorders. Aβ normally regulates neuronal synaptic function and repair; however, the intracellular accumulation of Aβ within the brain has been observed to play a critical role in AD pathology. A portion of Aβ is believed to originate from the brain itself and can readily cross the blood-brain barrier, while the rest resides in peripheral tissues that express APP required for Aβ generation such as the liver, pancreas, kidney, spleen, skin, and lungs. Consequently, numerous organs contribute to the body pool of total circulating Aβ, which can accumulate in the brain and facilitate neurodegeneration. Although the accumulation of Aβ corresponds with the onset of neurodegenerative disorders, the direct function of periphery born Aβ in AD pathophysiology is currently unknown. This review will highlight the contributions of individual cardiometabolic diseases including cardiovascular disease (CVD), type 2 diabetes (T2D), obesity, and non-alcoholic fatty liver disease (NAFLD) in elevating concentrations of circulating Aβ within the brain, as well as discuss the comorbid association of Aβ with AD pathology.

Nutrigenomics in Regulating the Expression of Genes Related to Type 2 Diabetes Mellitus

Nutrigenomics is the study of the gene-nutrient interaction and it indicates that some nutrients, called bioactive compounds, can mold the genetic expression or change the nucleotide chain. Polyphenols are secondary metabolites found in plants that are regularly consumed in functional foods and help prevent or delay the onset of type 2 diabetes mellitus (T2DM) and its complications. This article objected to review studies about the interaction of diet with polyphenols and Mediterranean diet in the expression of human genes related to T2DM. Resveratrol acts as an antioxidant, anti-inflammatory, and increases mitochondrial function. Regular consumption of quercetin resulted in improvement of hypertension and suppression of diabetes-induced vasoconstriction. Genistein also showed positive results in T2DM, such as increased cell mass and improved glucose tolerance and insulin levels. Catechins showed efficiency in inducing genes in triacylglycerol biosynthesis, inhibition of fatty acids and cholesterol, and resulting in their participation in mitigating complications of diabetes. Lastly, curcumin was demonstrated to be a protector of the pancreatic islets against streptozotocin-induced oxidative stress. Growing evidence suggest that bioactive compounds such as polyphenols have an important role in T2DM and the prevention and treatment of its complication, as they cause activation or inhibition of related genes.

Improving Drug Delivery for Alzheimer's Disease Through Nose-to-Brain Delivery Using Nanoemulsions, Nanostructured Lipid Carriers (NLC) and in situ Hydrogels

Current treatments for Alzheimer's disease (AD) attenuate the progression of symptoms and aim to improve the patient's quality of life. Licensed medicines are mostly for oral administration and are limited by the difficulty in crossing the blood-brain barrier (BBB). Here in, the nasal route has been explored as an alternative pathway that allows drugs to be directly delivered to the brain via the nasal cavity. However, clearance mechanisms in the nasal cavity impair the delivery of drugs to the brain and limit their bioavailability. To optimize nose-to-brain delivery, formulations of lipid-based nanosystems, namely nanoemulsions and nanostructured lipid carriers (NLC), formulated in situ gelling hydrogels have been proposed as approaches for nose-to-brain delivery. These formulations possess characteristics that facilitate drug transport directly to the brain, minimizing side effects and maximizing therapeutic benefits. It has been recommended that the manufacture of these drug delivery systems follows the quality by design (QbD) approach based on nasal administration requirements. This review provides an insight into the current knowledge of the AD, highlighting the need for an effective drug delivery to the brain. Considering the mounting interest in the use of nanoemulsions and NLC for nose-to-brain delivery, a description of drug transport pathways in the nasal cavity and the application of these nanosystems and their in situ hydrogels through the intranasal route are presented. Relevant preclinical studies are summarised, and the future prospects for the use of lipid-based nanosystems in the treatment of AD are emphasized.

Pathology, Risk Factors, and Oxidative Damage Related to Type 2 Diabetes-Mediated Alzheimer's Disease and the Rescuing Effects of the Potent Antioxidant Anthocyanin

The pathology and neurodegeneration in type 2 diabetes- (T2D-) mediated Alzheimer's disease (AD) have been reported in several studies. Despite the lack of information regarding the basic underlying mechanisms involved in the development of T2D-mediated AD, some common features of the two conditions have been reported, such as brain atrophy, reduced cerebral glucose metabolism, and insulin resistance. T2D phenotypes such as glucose dyshomeostasis, insulin resistance, impaired insulin signaling, and systemic inflammatory cytokines have been shown to be involved in the progression of AD pathology by increasing amyloid-beta accumulation, tau hyperphosphorylation, and overall neuroinflammation. Similarly, oxidative stress, mitochondrial dysfunction, and the generation of advanced glycation end products (AGEs) and their receptor (RAGE) as a result of chronic hyperglycemia may serve as critical links between diabetes and AD. The natural dietary polyflavonoid anthocyanin enhances insulin sensitivity, attenuates insulin resistance at the level of the target tissues, inhibits free fatty acid oxidation, and abrogates the release of peripheral inflammatory cytokines in obese (prediabetic) individuals, which are responsible for insulin resistance, systemic hyperglycemia, systemic inflammation, brain metabolism dyshomeostasis, amyloid-beta accumulation, and neuroinflammatory responses. In this review, we have shown that obesity may induce T2D-mediated AD and assessed the recent therapeutic advances, especially the use of anthocyanin, against T2D-mediated AD pathology. Taken together, the findings of current studies may help elucidate a new approach for the prevention and treatment of T2D-mediated AD by using the polyflavonoid anthocyanin.

Natural Bioactive Compounds Useful in Clinical Management of Metabolic Syndrome

Metabolic syndrome (MetS) is a clinical manifestation characterized by a plethora of comorbidities, including hyperglycemia, abdominal obesity, arterial hypertension, and dyslipidemia. All MetS comorbidities participate to induce a low-grade inflammation state and oxidative stress, typical of this syndrome. MetS is related to an increased risk of cardiovascular diseases and early death, with an important impact on health-care costs. For its clinic management a poly-pharmaceutical therapy is often required, but this can cause side effects and reduce the patient's compliance. For this reason, finding a valid and alternative therapeutic strategy, natural and free of side effects, could represent a useful tool in the fight the MetS. In this context, the use of functional foods, and the assumption of natural bioactive compounds (NBCs), could exert beneficial effects on body weight, blood pressure and glucose metabolism control, on endothelial damage, on the improvement of lipid profile, on the inflammatory state, and on oxidative stress. This review focuses on the possible beneficial role of NBCs in the prevention and in the clinical management of MetS and its comorbidities.

Polyphenols and Cognition In Humans: An Overview of Current Evidence from Recent Systematic Reviews and Meta-Analyses

BACKGROUND

There is increasing interest in the impact of dietary influences on the brain throughout the lifespan, ranging from improving cognitive development in children through to attenuating ageing related cognitive decline and reducing risk of neurodegenerative diseases. Polyphenols, phytochemicals naturally present in a host of fruits, vegetables, tea, cocoa and other foods, have received particular attention in this regard, and there is now a substantial body of evidence from experimental and epidemiological studies examining whether their consumption is associated with cognitive benefits.

OBJECTIVE

The purpose of this overview is to synthesise and evaluate the best available evidence from two sources, namely meta-analyses and systematic reviews, in order to give an accurate reflection of the current evidence base for an association between polyphenols and cognitive benefits.

METHOD

Four meta-analyses and thirteen systematic reviews published between 2017-2020 were included, and were categorised according to whether they reviewed specific polyphenol-rich foods and classes or all polyphenols. A requirement for inclusion was assessment of a behavioural cognitive outcome in humans.

RESULTS

A clear and consistent theme emerged that whilst there is support for an association between polyphenol consumption and cognitive benefits, this conclusion is tentative, and by no means definitive. Considerable methodological heterogeneity was repeatedly highlighted as problematic such that the current evidence base does not support reliable conclusions relating to efficacy of specific doses, duration of treatment, or sensitivity in specific populations or certain cognitive domains. The complexity of multiple interactions between a range of direct and indirect mechanisms of action is discussed.

CONCLUSIONS

Further research is required to strengthen the reliability of the evidence base.

Reno-Hepatoprotective and Antidiabetic Properties of Methanol Leaf Extract of Laportea Aestuans in Wistar Rats

Toxicities due to exposure to arsenic-contaminated water and the occurrence of diabetes mellitus are major health concerns. Treatment of these concerns using therapeutic measures have recorded limited success. Traditionally, Laportea aestuans (LA) has been used in managing various diseases. Hence, we investigated the reno-hepatoprotective/antidiabetic potentials of methanol leaf extract of LA (MeLELA) in male Wistar rats. Thirty rats (100-150 g) were equally distributed into 6 groups: Group I (vehicle-treated); group II received 2.5 mg/kg sodium arsenite (SA) thrice a week for 2 weeks; group III received streptozotocin (STZ, 50 mg/kg once); group IV received 200 mg/kg LA daily for 14 days; group V received SA and LA; group VI received STZ and LA. Sodium arsenite and STZ induced reno-hepatotoxicity and diabetes, respectively. Phytochemical screening, biomarkers/enzyme activities, blood glucose levels, micronucleus assay, kidney, liver and pancreas histologies were determined according to standard procedures. Alkaloids, carotenoids and flavonoids were present in abundance. Both SA-and STZ-treated groups recorded significant (p < 0.05) reductions in serum protein concentrations, while co-treatment with LA significantly restored the levels. The SA-induced significant increase in creatinine/urea levels were significantly reduced by LA. Co-treatment of each of SA-and STZ-treated groups, respectively, with LA significantly decreased the elevated serum alanine and aspartate aminotransferases' activities. Increased blood glucose level in diabetic group was remarkably lowered by LA. Also, the SA-induced frequency of micronucleated polychromatic erythrocytes was significantly ameliorated by LA. Conclusively, LA is protective against SA-induced toxicity and STZ-induced diabetes in Wistar rats.

Oral Nano Drug Delivery Systems for the Treatment of Type 2 Diabetes Mellitus: An Available Administration Strategy for Antidiabetic Phytocompounds

In view of the worldwide serious health threat of type 2 diabetes mellitus (T2DM), natural sources of chemotherapies have been corroborated as the promising alternatives, with the excellent antidiabetic activities, bio-safety, and more cost-effective properties. However, their clinical application is somewhat limited, because of the poor solubility, instability in the gastrointestinal tract (GIT), low bioavailability, and so on. Nowadays, to develop nanoscaled systems has become a prominent strategy to improve the drug delivery of phytochemicals. In this review, we primarily summarized the intervention mechanisms of phytocompounds against T2DM and presented the recent advances in various nanosystems of antidiabetic phytocompounds. Selected nanosystems were grouped depending on their classification and structures, including polymeric NPs, lipid-based nanosystems, vesicular systems, inorganic nanocarriers, and so on. Based on this review, the state-of-the-art nanosystems for phytocompounds in T2DM treatment have been presented, suggesting the preponderance and potential of nanotechnologies.

Glycemic traits and Alzheimer's disease: a Mendelian randomization study

Previous observational studies have reported an association between impaired glucose metabolism and Alzheimer’s disease. This study aimed to examine the causal association of glycemic traits with Alzheimer’s disease. We used a two-sample Mendelian randomization approach to evaluate the causal effect of six glycemic traits (type 2 diabetes, fasting glucose, fasting insulin, hemoglobin A1c, homeostasis model assessment- insulin resistance and HOMA-β-cell function) on Alzheimer’s disease. Summary data on the association of single nucleotide polymorphisms with these glycemic traits were obtained from genome-wide association studies of the DIAbetes Genetics Replication And Meta-analysis and Meta-Analyses of Glucose and Insulin-related traits Consortium. Summary data on the association of single nucleotide polymorphisms with Alzheimer’s disease were obtained from the International Genomics of Alzheimer's Project. The Mendelian randomization analysis showed that 1-standard deviation higher fasting glucose and lower HOMA-β-cell function (indicating pancreatic β-cell dysfunction) were causally associated with a substantial increase in risk of Alzheimer’s disease (odds ratio=1.33, 95% confidence interval: 1.04-1.68, p=0.02; odds ratio=1.92, 95% confidence interval: 1.15-3.21, p=0.01). However, no significant association was observed for other glycemic traits. This Mendelian randomization analysis provides evidence of causal associations between glycemic traits, especially high fasting glucose and pancreatic β-cell dysfunction, and high risk of Alzheimer's disease.

Important Flavonoids and Their Role as a Therapeutic Agent

Flavonoids are phytochemical compounds present in many plants, fruits, vegetables, and leaves, with potential applications in medicinal chemistry. Flavonoids possess a number of medicinal benefits, including anticancer, antioxidant, anti-inflammatory, and antiviral properties. They also have neuroprotective and cardio-protective effects. These biological activities depend upon the type of flavonoid, its (possible) mode of action, and its bioavailability. These cost-effective medicinal components have significant biological activities, and their effectiveness has been proved for a variety of diseases. The most recent work is focused on their isolation, synthesis of their analogs, and their effects on human health using a variety of techniques and animal models. Thousands of flavonoids have been successfully isolated, and this number increases steadily. We have therefore made an effort to summarize the isolated flavonoids with useful activities in order to gain a better understanding of their effects on human health.

Betanin as a multipath oxidative stress and inflammation modulator: a beetroot pigment with protective effects on cardiovascular disease pathogenesis

Oxidative stress is a common physiopathological condition enrolled in risk factors for cardiovascular diseases. Individuals in such a redox imbalance status present endothelial dysfunctions and inflammation, reaching the onset of heart disease. Phytochemicals are able to attenuate the main mechanisms of oxidative stress and inflammation and should be considered as supportive therapies to manage risk factors for cardiovascular diseases. Beetroot (Beta vulgaris L.) is a rich source of bioactive compounds, including betanin (betanidin-5-O-β-glucoside), a pigment displaying the potential to alleviate oxidative stress and inflammantion, as previously demonstrated in preclinical trials. Betanin resists gastrointestinal digestion, is absorbed by the epithelial cells of intestinal mucosa and reaches the plasma in its active form. Betanin displays free-radical scavenger ability through hydrogen or electron donation, preserving lipid structures and LDL particles while inducing the transcription of antioxidant genes through the nuclear factor erythroid-2-related factor 2 and, simultaneously, suppressing the pro-inflammatory nuclear factor kappa-B pathways. This review discusses the anti-radical and gene regulatory cardioprotective activities of betanin in the pathophysiology of endothelial damage and atherogenesis, the main conditions for cardiovascular disease. In addition, betanin influences on these multipath cellular signals and aiding in reducing cardiovascular disorders is proposed.

Management of Type 2 Diabetes: Current Strategies, Unfocussed Aspects, Challenges, and Alternatives

Type 2 diabetes mellitus (T2DM) accounts for >90% of the cases of diabetes in adults. Resistance to insulin action is the major cause that leads to chronic hyperglycemia in diabetic patients. T2DM is the consequence of activation of multiple pathways and factors involved in insulin resistance and β-cell dysfunction. Also, the etiology of T2DM involves the complex interplay between genetics and environmental factors. This interplay can be governed efficiently by lifestyle modifications to achieve better management of diabetes. The present review aims at discussing the major factors involved in the development of T2DM that remain unfocussed during the anti-diabetic therapy. The review also focuses on lifestyle modifications that are warranted for the successful management of T2DM. In addition, it attempts to explain flaws in current strategies to combat diabetes. The employability of phytoconstituents as multitargeting molecules and their potential use as effective therapeutic adjuvants to first line hypoglycemic agents to prevent side effects caused by the synthetic drugs are also discussed.

Beneficial Effect of Genistein on Diabetes-Induced Brain Damage in the ob/ob Mouse Model

Purpose

Diabetes mellitus (DM)-induced brain damage is characterized by cellular, molecular and functional changes. The mechanisms include oxidative stress, neuroinflammation, reduction of neurotrophic factors, insulin resistance, excessive amyloid beta (Aβ) deposition and Tau phosphorylation. Both antidiabetic and neuroprotective effects of the phytoestrogen genistein have been reported. However, the beneficial effect of genistein in brain of the ob/ob mouse model of severe obesity and diabetes remains to be determined.

Methods

In this study, female ob/ob mice and lean control mice were fed with either a standard diet or a diet containing genistein (600mg/kg) for a period of 4 weeks. Body weight was monitored weekly. Blood was collected for the measurement of glucose, insulin and common cytokines. Mice brains were isolated for Western immunoblotting analyses.

Results

Treatment with genistein reduced weight gain of ob/ob mice and decreased hyperglycemia compared to ob/ob mice fed the standard diet. The main findings show that genistein treatment increased insulin sensitivity and the expression levels of the neurotrophic factors nerve growth factor (NGF) and brain-derived neurotrophic factors (BDNF). In these mice, genistein also reduced Aβ deposition and the level of hyper-phosphorylated Tau protein.

Conclusion

The results of our study indicate the beneficial effects of genistein in the obese diabetic mouse brain, including improving brain insulin signaling, increasing neurotrophic support, and alleviating Alzheimer’s disease-related pathology.

Effect of Caesalpinia bonduc Polyphenol Extract on Alloxan-Induced Diabetic Rats in Attenuating Hyperglycemia by Upregulating Insulin Secretion and Inhibiting JNK Signaling Pathway

Caesalpinia bonduc has been used in herbal medicines for the treatment of a wide range of diseases from decades. The present study has explored the remedial potential and underlying mechanism of polyphenol extract of Caesalpinia bonduc in alloxanized diabetic rats. HPLC/MS analysis confirmed the presence of phenolics in considerable concentrations in Caesalpinia bonduc extract. Administration of different doses (250 and 500 mg/kg) of CPP extract to hyperglycemic rats for 8 weeks restored blood and serum glucose, insulin, glycosylated hemoglobin, leptin, amylin, and carbohydrate metabolizing enzymes level towards normal compared to alloxanized diabetic group. The effect of CPP extract on various genes such as Pdx-1, Ins-1, ngn-3, GLUT-4, and IRS-1 in insulin signaling pathway and Traf-4, Traf-6, and Mapk-8 in MAPK downstream JNK cascade was examined through qRT-PCR to access the core molecular mechanism involved in CPP-induced recovery of diabetes. Results have revealed that CPP extract reduced oxidative stress in pancreatic β cells by restoring free radical scavenging potential, reducing the mRNA expression of Mapk-8, Traf-4, and Traf-6, and increasing the Pdx-1, Ins-1, ngn-3, GLUT-4, and IRS-1 expression ensuing regeneration of β cells and subsequent insulin release from pancreas. The results obtained in this study recommend that CPP extract may be a promising therapeutic restorative agent in the treatment of diabetes mellitus.

Increased Brain Iron Deposition in the Putamen in Patients with Type 2 Diabetes Mellitus Detected by Quantitative Susceptibility Mapping

BACKGROUND

The underlying brain structural changes in type 2 diabetes mellitus (T2DM) patients have attracted increasing attention. The insulin-resistant state causes iron overload in neurons and leads to lesions in the central nervous system. Quantitative susceptibility mapping (QSM) can provide a noninvasive quantitative analysis of brain iron deposition. We aimed to compare the difference of brain iron deposition in the gray matter nucleus between T2DM patients and healthy elderly individuals using QSM.

METHODS

Thirty-two T2DM patients and thirty-two age- and gender-matched healthy controls (HCs) were enrolled in this research. Twenty-three patients and twenty-six HCs underwent cognitive assessments. Brain QSM maps were computed from multiecho GRE data using morphology-enabled dipole inversion with automatic uniform cerebrospinal fluid zero reference algorithm (MEDI+0). ITK-SNAP was used to measure the susceptibility values reflecting the content of iron in the regions of interest (ROIs).

RESULTS

The study included thirty-two T2DM patients (20 males and 12 females; mean age of 61.09 ± 9.99 years) and 32 HCs (14 males and 18 females; mean age of 59.09 ± 9.77 years). These participants had no significant difference in age or gender (P > 0.05). Twenty-three patients with T2DM (11 males and 12 females; mean age, 64.65 ± 8.44 years) and twenty-six HCs (14 males and 12 females; mean age, 62.30 ± 6.13 years) received an assessment of cognitive function. T2DM patients exhibited an obviously (t = 3.237, P = 0.003) lower Montreal Cognitive Assessment (MoCA) score (26.78 ± 2.35; HCs, 28.42 ± 0.64; normal standard ≥26) and a higher Stroop color-word test (SCWT)-C score [87(65,110); HC, 63(60,76.75), Z = -2.232, P = 0.003] than HCs. The mean susceptibility values in the putamen appeared obviously higher in T2DM patients than in HCs (t = -3.994, P < 0.001). The susceptibility values and cognitive assessment scores showed no obvious association (P > 0.05). However, an obvious correlation was observed between the changes in the susceptibility values in the putamen and the thalamus/dentate nucleus (r = 0.404, P < 0.001; r = 0.423, P < 0.001).

CONCLUSION

T2DM patients showed increased susceptibility values in the putamen and had declines in executive functions, but the linear association between them was not statistically significant. Changes in susceptibility values in the putamen indicated increased iron deposition and might be used as a quantitative imaging marker of central nervous system injury in T2DM patients. QSM might be able to help probe micro neuronal damage in gray matter and provide information on diabetic encephalopathy.

Effect of the ZiBuPiYin Recipe on Diabetes-Associated Cognitive Decline in Zucker Diabetic Fatty Rats After Chronic Psychological Stress

BACKGROUND

Cognitive impairment is a complication of type 2 diabetes mellitus (T2DM) that affects the central nervous system (CNS). Studies have shown that chronic psychological stress may promote the development of T2DM into diabetes-associated cognitive decline (DACD). Previously, cognitive impairment in T2DM was correlated predominantly with insulin resistance in the medial prefrontal cortex (mPFC).

AIMS

We examined the effect of the ZiBuPiYin recipe (ZBPYR) on Zucker diabetic fatty (ZDF) rats and explored the impact of chronic stress on altered β-amyloid (Aβ) metabolism through insulin receptor substrate (IRS) 1/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway after the induction of chronic psychological stress.

MAIN METHODS

After chronic psychological stress and drug treatment, cognitive function was observed via behavioral experiments. The activation of the hypothalamus-pituitary-adrenal (HPA) axis and levels of Aβ were detected by enzyme-linked immunosorbent assay, and the expression of related proteins was evaluated by Western blotting.

KEY FINDINGS

ZBPYR treatment significantly decreased anxious-like behaviors and plasma corticosterone (CORT) levels, and ameliorated learning and memory impairments of ZDF rats after chronic psychological stress. ZBPYR also reduced the deposition of Aβ in the mPFC, improved brain insulin resistance, and modulated the mTOR-autophagy pathway.

SIGNIFICANCE

ZBPYR may be a potential therapeutic application for the treatment of DACD induced by chronic psychological stress.