Naringin (4',5,7-Trihydroxyflavanone 7-Rhamnoglucoside) Attenuates β-Cell Dysfunction in Diabetic Rats through Upregulation of PDX-1

Naringin: Cardioprotective properties and safety profile in diabetes treatment

Flavonoids derived from plants offer a broad spectrum of therapeutic potential for addressing metabolic syndrome, particularly diabetes mellitus (DM), a prevalent non-communicable disease. Hyperglycemia in DM is a known risk factor for cardiovascular diseases (CVDs), which substantially impact global mortality rates. This review examines the potential effects of naringin, a citrus flavonoid, on both DM and its associated cardiovascular complications, including conditions like diabetic cardiomyopathy. The safety profile of naringin is summarized based on various pre-clinical studies. The data for this review was gathered from diverse electronic databases, including Medline, PubMed, ScienceDirect, SpringerLink, Google Scholar, and Emerald Insight. Multiple pre-clinical studies have demonstrated that naringin exerts hypoglycemic and cardioprotective effects by targeting various vascular mechanisms. Specifically, research indicates that naringin down-regulates the renin-angiotensin and oxidative stress systems while concurrently upregulating β-cell and immune system functions. Clinical trial outcomes also support the therapeutic potential of naringin in managing hyperglycemic states and associated cardiovascular issues. Moreover, toxicity studies have confirmed the safety of naringin in animal models, suggesting its potential for safe administration in humans. In conclusion, naringin emerges as a promising natural candidate for both antidiabetic and cardioprotective purposes, offering potential improvements in health outcomes. While naringin presents a new avenue for therapies targeting DM and CVDs, additional controlled and long-term clinical trials are necessary to validate its efficacy and safety for human use.

The association between circulatory, local pancreatic PCSK9 and type 2 diabetes mellitus: The effects of antidiabetic drugs on PCSK9

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a potent modulator of cholesterol metabolism and plays a crucial role in the normal functioning of pancreatic islets and the progression of diabetes. Islet autocrine PCSK9 deficiency can lead to the enrichment of low-density lipoprotein (LDL) receptor (LDLR) and excessive LDL cholesterol (LDL-C) uptake, subsequently impairing the insulin secretion in β-cells. Circulatory PCSK9 levels are primarily attributed to hepatocyte secretion. Notably, anti-PCSK9 strategies proposed for individuals with hypercholesterolemia chiefly target liver-derived PCSK9; however, these anti-PCSK9 strategies have been associated with the risk of new-onset diabetes mellitus (NODM). In the current review, we highlight a new direction in PCSK9 inhibition therapy strategies: screening candidates for anti-PCSK9 from the drugs used in type 2 diabetes mellitus (T2DM) treatment. We explored the association between circulating, local pancreatic PCSK9 and T2DM, as well as the relationship between PCSK9 monoclonal antibodies and NODM. We discussed the emergence of artificial and natural drugs in recent years, exhibiting dual benefits of antidiabetic activity and PCSK9 reduction, confirming that the diverse effects of these drugs may potentially impact the progression of diabetes and associated disorders, thereby introducing novel avenues and methodologies to enhance disease prognosis.

PDX-1: A Promising Therapeutic Target to Reverse Diabetes

The pancreatic duodenum homeobox-1 (PDX-1) is a transcription factor encoded by a Hox-like homeodomain gene that plays a crucial role in pancreatic development, β-cell differentiation, and the maintenance of mature β-cell functions. Research on the relationship between PDX-1 and diabetes has gained much attention because of the increasing prevalence of diabetes melitus (DM). Recent studies have shown that the overexpression of PDX-1 regulates pancreatic development and promotes β-cell differentiation and insulin secretion. It also plays a vital role in cell remodeling, gene editing, and drug development. Conversely, the absence of PDX-1 increases susceptibility to DM. Therefore, in this review, we summarized the role of PDX-1 in pancreatic development and the pathogenesis of DM. A better understanding of PDX-1 will deepen our knowledge of the pathophysiology of DM and provide a scientific basis for exploring PDX-1 as a potential target for treating diabetes.

The new exploration of pure total flavonoids extracted from Citrus maxima (Burm.) Merr. as a new therapeutic agent to bring health benefits for people

The peel and fruit of Citrus varieties have been a raw material for some traditional Chinese medicine (TCM). Pure total flavonoids from Citrus maxima (Burm.) Merr. (PTFC), including naringin, hesperidin, narirutin, and neohesperidin, have been attracted increasing attention for their multiple clinical efficacies. Based on existing in vitro and in vivo research, this study systematically reviewed the biological functions of PTFC and its components in preventing or treating liver metabolic diseases, cardiovascular diseases, intestinal barrier dysfunction, as well as malignancies. PTFC and its components are capable of regulating glycolipid metabolism, blocking peroxidation and persistent inflammation, inhibiting tumor progression, protecting the integrity of intestinal barrier and positively regulating intestinal microbiota, while the differences in fruit cultivation system, picking standard, manufacturing methods, delivery system and individual intestinal microecology will have impact on the specific therapeutic effect. Thus, PTFC is a promising drug for the treatment of some chronic diseases, as well as continuous elaborate investigations are necessary to improve its effectiveness and bioavailability.

Fucoidan protects pancreas and improves glucose metabolism through inhibiting inflammation and endoplasmic reticulum stress in T2DM rats

It is important to maintain the normal function of pancreas in the prevention and intervention of type 2 diabetes mellitus (T2DM). This study was undertaken to explore the protective effects...

New Perspectives in the Pharmacological Potential of Naringin in Medicine

BACKGROUND

Naringin (NAR) is a flavonoid enriched in several medicinal plants and fruits. An increasing interest in this molecule has emerged because it has the potential to contribute to alleviating many health problems.

OBJECTIVE

This review briefly describes the NAR pharmacokinetics and it mainly focuses on the in vitro and in vivo animal studies showing NAR beneficial effects on cardiovascular, metabolic, neurological and pulmonary disorders and cancer. The anabolic effects of NAR on different models of bone and dental diseases are also analyzed. In addition, the evidence of the NAR action on the gastrointestinal tract is reported as well as its influence on the microbiota composition and activity. Finally, current research on NAR formulations and clinical applications are discussed.

METHODS

The PubMed database was searched until 2019, using the keywords NAR, naringenin, cardiovascular and metabolic disorders, neurological and pulmonary disorders, cancer, bone and dental diseases, gastrointestinal tract, microbiota, NAR formulations, clinical trials.

RESULTS

The number of studies related to the bioavailability and pharmacokinetics of NAR is limited. Positive effects of NAR have been reported on cardiovascular diseases, Type 2 Diabetes Mellitus (T2DM), metabolic syndrome, pulmonary disorders, neurodegenerative diseases, cancer, and gastrointestinal pathologies. The current NAR formulations seem to improve its bioavailability, which would allow its clinical applications.

CONCLUSION

NAR is endowed with broad biological effects that could improve human health. Since a scarce number of clinical studies have been performed, the NAR use requires more investigation in order to know better their safety, efficacy, delivery, and bioavailability in humans.

Citrus flavanone metabolites protect pancreatic-β cells under oxidative stress induced by cholesterol

Cholesterol is one of the triggers of oxidative stress in the pancreatic-β cell, generating high levels of reactive oxygen species, which leads to impairment of insulin synthesis and secretion. Bioactive compounds, such as citrus flavanones, which possess anti-inflammatory and antioxidant activities, could reduce oxidative stress in β-cells and improve their function. We describe for the first time the protective effects of the phase-II flavanone metabolites [naringenin 7-O-glucuronide, hesperetin 3'-O-glucuronide, and hesperetin 7-O-glucuronide], and two flavanones-catabolites derived from gut microbiota metabolism [hippuric acid and 3-(4-hydroxyphenyl)propionic acid], on pancreatic β-cell line MIN6 under oxidative stress, at physiologically relevant concentration. Cholesterol reduced cell viability in a dose and time-dependent manner, with an improvement in the presence of the metabolites. Moreover, flavanone metabolites attenuated oxidative stress by reducing levels of lipid peroxides, superoxide anions, and hydrogen peroxide. In response to the reduction of reactive oxygen species, a decrease in superoxide dismutase and glutathione peroxidase activities was observed; these activities were elevated by cholesterol. Moreover, all the flavanone metabolites improved mitochondrial function and insulin secretion, and reduced apoptosis. Flavanone metabolites were found uptake by β-cells, and therefore could be responsible for the observed protective effects. These results demonstrated that circulating phase-II hesperetin and naringenin metabolites, and also phenolics derived from gut microbiota, protect pancreatic-β cells against oxidative stress, leading to an improvement in β-cell function and could be the bioactive molecules derived from the citrus consumption.

Angiotensin-(1-7) Improves Islet Function in a Rat Model of Streptozotocin- Induced Diabetes Mellitus by Up-Regulating the Expression of Pdx1/Glut2

OBJECTIVE

To observe the effects of angiotensin-(1-7) (Ang-(1-7)) on glucose metabolism, islet function and insulin resistance in a rat model of streptozotocin-induced diabetes mellitus (DM) and investigate its mechanism.

METHODS

Thirty-four male Wistar rats were randomly divided into 3 groups: control group, which was fed a standard diet, DM group, high-fat diet and injected with streptozotocin, and Ang-(1-7) group receiving an injection of streptozotocin followed by Ang-(1-7) treatment. Blood glucose level, fasting serum Ang II and insulin levels, and homeostasis model assessment of insulin resistance (HOMA-IR) were measured. The pancreases were collected for histological examination, protein and gene expression analysis.

RESULTS

Compared with the control group, fasting blood glucose, serum angiotensin II level, and HOMA-IR value increased, while serum insulin level decreased in the DM group. Moreover, islet structure was damaged, β cells were irregularly arranged, the cytoplasm was loose in the DM group. Expressions of Pancreatic duodenal homeobox-1 (Pdx1), glucose transporter-2 (Glut2) and glucokinase (Gk) were significantly decreased in the DM group compared with the control group. However, the DM-associated changes were dramatically reversed following Ang-(1-7) treatment.

CONCLUSION

Ang-(1-7) protects against streptozotocin-induced DM through the improvement of insulin secretion, insulin resistance and islet fibrosis, which is associated with the upregulation of Pdx1, Glut2 and Gk expressions.

Islet Stellate Cells Regulate Insulin Secretion via Wnt5a in Min6 Cells

BACKGROUND

Type 2 diabetes mellitus is a serious public health problem worldwide. Accumulating evidence has shown that β-cell dysfunction is an important mechanism underlying diabetes mellitus. The changes in the physiological state of islet stellate cells (ISCs) and the effects of these cells on β-cell dysfunction is an important mechanism underlying diabetes mellitus. The changes in the physiological state of islet stellate cells (ISCs) and the effects of these cells on.

METHODS

Glucose-stimulated insulin secretion (GSIS) from Min6 cells was examined by estimating the insulin levels in response to high glucose challenge after culture with ISC supernatant or exogenous Wnt5a. Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) analyses were used to observe changes in the β-cell dysfunction is an important mechanism underlying diabetes mellitus. The changes in the physiological state of islet stellate cells (ISCs) and the effects of these cells on.

RESULTS

We observed a significant increase in insulin secretion from Min6 cells cocultured in vitro with supernatant from db/m mouse ISCs compared to that from Min6 cells cocultured with supernatant from db/db mouse ISCs; The intracellular Ca²⁺ concentration in Min6 cells increased in cultured in vitro with supernatant from db/m mouse ISCs and exogenous Wnt5a compared to that from control Min6 cells. Culture of Min6 cells with exogenous Wnt5a caused a significant increase in pCamKII, pFoxO1, PDX-1, and Glut2 levels compared to those in Min6 cells cultured alone; this treatment further decreased Ror2 and Cask expression but did not affect β-cell dysfunction is an important mechanism underlying diabetes mellitus. The changes in the physiological state of islet stellate cells (ISCs) and the effects of these cells on.

CONCLUSION

ISCs regulate insulin secretion from Min6 cells through the Wnt5a protein-induced Wnt-calcium and FoxO1-PDX1-GLUT2-insulin signalling cascades.