Garlic decreases liver and kidney receptor for advanced glycation end products expression in experimental diabetes

Among Other Tissues, Short-Term Garlic Oral Treatment Incrementally Improves Indicants of Only Pancreatic Islets of Langerhans Histology and Insulin mRNA Transcription and Synthesis in Diabetic Rats

BACKGROUND

The source, mRNA transcription, and synthesis of insulin in the pancreas, in addition to the bile duct and liver, in streptozotocin (STZ)-induced diabetic rats (DR) in response to garlic oral treatment are not yet clear.

OBJECTIVE

This study investigated the accumulative effects of continued garlic oral treatment on changes in the pancreas, bile duct, and liver with regards to: 1-Insulin mRNA transcription, synthesis, and concentration in relation to changes in serum insulin (SI); 2-Insulinogenic cells insulin intensity and distribution, proliferation, and morphology.

METHOD

Fasting blood glucose (FBG) and insulin concentration in serum and pancreas (PI) and sources and mRNA transcription in the pancreas, bile duct, and liver in normal rats given normal saline (NR-NS) and DR given either NS (DR-NS) or garlic extract (DR-GE) before and after 1, 4, and 8 weeks of oral treatment were examined.

RESULTS

Compared to NR-NS, DR-NS showed a significant increase in FBG and reductions in SI and PI and deterioration in islets histology, associated pancreatic insulin numerical intensities, and mRNA transcription. However, compared to DR-NS, the targeted biochemical, histological, and genetic variables of DR-GE were significantly and incrementally improved as garlic treatment continued. Insulin or its indicators were not detected either in the bile duct or the liver in DR-GE.

CONCLUSIONS

8 weeks of garlic oral treatment is enough to incrementally restore only pancreatic islets of Langerhans insulin intensity and insulinogenic cells proliferation, morphology, and distribution. These indices were associated with enhanced pancreatic insulin mRNA transcription and synthesis. Eight weeks of garlic treatment were not enough to stimulate insulinogenesis in either the bile duct or the liver.

Garlic (Allium sativum L.) in diabetes and its complications: Recent advances in mechanisms of action

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia and impaired islet secretion that places a heavy burden on the global health care system due to its high incidence rate, long disease course and many complications. Fortunately, garlic (Allium sativum L.), a well-known medicinal plant and functional food without the toxicity and side effects of conventional drugs, has shown positive effects in the treatment of diabetes and its complications. With interdisciplinary development and in-depth exploration, we offer a clear and comprehensive summary of the research from the past ten years, focusing on the mechanisms and development processes of garlic in the treatment of diabetes and its complications, aiming to provide a new perspective for the treatment of diabetes and promote the efficient development of this field.

Synergistic properties of garlic and Citrullus colocynthis on reproductive injury caused by diabetes in male rats: Structural and molecular evidence

This study evaluates the synergistic effect of garlic and Citrullus colocynthis on diabetic reproductive damage by suppressing the AGEs/RAGE/Nox-4 signaling pathway. Thirty-five male Wistar rats were divided into five groups (n = 7/group): Control, Diabetic, Diabetic+G (Garlic, 1 mL/100 g b.w), Diabetic+C (C. colocynthis, 10 mg/kg b.w) and Diabetic+GC (Garlic, 1 mL/100 g b.w and C. colocynthis, 10 mg/kg b.w) groups. At the end of the experimental period (30 days), in diabetic rats, glucose increased, and body & testis weight, luteinizing hormone (LH) and testosterone levels, and sperm count decreased significantly and histopathological injuries were observed. In addition, they have increased testicular apoptosis and oxidative stress. Also, the mechanism based on advanced glycation end products (AGEs)/receptors for advanced glycation end products (RAGE)/NADPH oxidase-4 (Nox-4) was activated in diabetic rats. Separate consumption of garlic and C. colocynthis in Diabetic+G and Diabetic+C groups alleviated the negative adverse effect of diabetes to some extent, but when they were used in the combination form (Diabetic+GC) improvement was profound. Testis histopathology, increased body and testis weight, and enhanced capacity in protecting diabetic reproductive injury was seen. Decreases in testosterone and LH concentration and sperm count in diabetic rats were also reversed by combined administration of garlic and C. colocynthis. It regulated oxidative stress markers, meanwhile reducing caspase-3 immunoexpression. In addition, overexpression of RAGE, Nox-4 and nuclear transcription factor-κB (NF-κB) was inhibited by the combination of garlic and C. colocynthis. PRACTICAL APPLICATIONS: Diabetes mellitus is wide spread all around the world with variety of complications in body including reproductive system in which patients suffer from physical and psychological aspects. Despite many efforts in providing agents for controlling diabetes and its complications, economic conditions of some countries make it difficult for people to provide costly medicine and as a result, they have to bear the complications until they pass away. However, traditional medicine is still finding its way, especially in poor countries with emphasis on medicinal plants. There have been many studies on plants to alleviate diabetes or its side effects. But, using one plant for long term, may be not so effective. Here, we attempted to find whether two plants from two different species can show more efficacy than each one alone. We noticed garlic and Citrullus colocynthis despite having beneficial effects when used alone, they could show synergistic effects in combination.

Correlation and Diagnostic Value of Serum RBP4 and sRAGE and the Condition of Patients with Chronic Kidney Disease

Chronic kidney disease (CKD) is a progressive damage of renal structure and function caused by various reasons. Its course is long and irreversible. CKD can be divided into 5 stages according to the glomerular filtration rate (GFR). Early detection and early intervention of CKD can reduce the complications of patients and improve the survival rate. Retinol-binding protein 4 (RBP4) is a small molecule transporter. Receptor for advanced glycation end products (RAGE) is a multi-ligand transmembrane signal transduction receptor discovered in recent years. Soluble RAGE (sRAGE) is a new splicing heterogeneity of RAGE. Our results show that serum RBP4 is increased while sRAGE is decreased in CKD patients, both of which are closely related to the severity of CKD. The combined use of serum RBP4 and sRAGE has a high diagnostic value for CKD and can provide a reliable diagnostic basis for the clinic.

Glycation and Antioxidants: Hand in the Glove of Antiglycation and Natural Antioxidants

The non-enzymatic interaction of sugar and protein resulting in the formation of advanced glycation end products responsible for cell signaling alterations ultimately leads to the human chronic disorders such as diabetes mellitus, cardiovascular diseases, cancer, etc. Studies suggest that AGEs upon interaction with receptors for advanced glycation end products (RAGE) result in the production of pro-inflammatory molecules and free radicals that exert altered gene expression effect. To date, many studies unveiled the potent role of synthetic and natural agents in inhibiting the glycation reaction at a lesser or greater extent. This review focuses on the hazards of glycation reaction and its inhibition by natural antioxidants, including polyphenols.

Natural Insulin Sensitizers for the Management of Diabetes Mellitus: A Review of Possible Molecular Mechanisms

Diabetes mellitus is a growing health challenge globally which is increasing in epidemic proportion. Naturally occurring pharmacological agents are more likely to provide beneficial therapeutic effects without undesirable side effects compared to the synthetic agents. There is a growing evidence that some naturally occurring pharmacological agents derived from plants have potential antihyperglycemic effects. In this study, we have reviewed the molecular mechanism behind potential hypoglycemic properties of four well-known herbal-based agents, namely, ginger, curcumin, garlic, and cinnamon. Also, we present the related clinical data confirming experimental results aiming to develop novel therapeutic strategies based on these herbal agents potentially for the management of patients with diabetes.

Orally administered resveratrol enhances the therapeutic effect of autologous transplanted adipose-derived stem cells on rats with diabetic hepatopathy

Stem cell therapy is a promising treatment for hepatopathy due to diabetes mellitus (DM); oral resveratrol treatment exhibits protective effects. We investigated whether protective effects could be produced in liver of diabetic rats receiving autologous adipose-derived stem cell transplantation (ADSC) plus oral resveratrol administration. Male rats were divided into four groups: sham group; streptozotocin induced DM group; DM + ADSC group, in which DM rats were treated with 10⁶ stem cells/rat; and DM + R + ADSC group, in which DM rats were treated with ADSC and oral resveratrol. The DM group exhibited apoptosis, inflammation and fibrosis, whereas Sirt-1 and survival signaling were suppressed. Pathological conditions other than survival signaling were improved in the DM + ADSC group. All pathological conditions were improved in the DM + R + ADSC group. Also, the oxidative stress level in the blood was reduced in the DM + R + ADSC group compared to the sham group. Oral resveratrol administration appears to reduce oxidative damage and enhances survival signaling in diabetic liver. The therapeutic response in the DM + R + ADSC group was better than in the DM + ADSC group.

Zingerone (4-(4-hydroxy-3-methylphenyl)butan-2-one) ameliorates renal function via controlling oxidative burst and inflammation in experimental diabetic nephropathy

Development of diabetic nephropathy (DN) is directly linked to oxidative stress and inflammation. In this context, inflammatory and oxidative markers have gained much attention as targets for therapeutic intervention. We studied the effect of zingerone in a streptozotocin/high fat diet (STZ/HFD)-induced type 2 diabetic Wistar rat model. Zingerone also known as vanillyl acetone is a pharmacologically active compound present usually in dry ginger. STZ/HFD caused excessive increase in ROS and inflammation in experimental animals. The treatment with zingerone markedly abrogated ROS levels, inhibited the NF-кB activation and considerably reduced level of other downstream inflammatory molecules (TNF-α, IL-6, IL-1β), furthermore, zingerone treatment improved renal functioning by significantly decreasing the levels of kidney toxicity markers KIM-1, BUN, creatinine, and LDH and suppressed TGF-β. Collectively, these findings indicate that zingerone treatment improved renal function by anti-hyperglycaemic, anti-oxidant, and anti-inflammatory effects, suggesting the efficacy of zingerone in the treatment of DN.

An Overview of Herbal Products and Secondary Metabolites Used for Management of Type Two Diabetes

Diabetes mellitus is a common effect of uncontrolled high blood sugar and it is associated with long-term damage, dysfunction, and failure of various organs. In the adult population, the global prevalence of diabetes has nearly doubled since 1980. Without effective prevention and management programs, the continuing significant rise in diabetes will have grave consequences on the health and lifespan of the world population, and also on the world economy. Supplements can be used to correct nutritional deficiencies or to maintain an adequate intake of certain nutrients. These are often used as treatments for diabetes, sometimes because they have lower costs, or are more accessible or "natural" compared to prescribed medications. Several vitamins, minerals, botanicals, and secondary metabolites have been reported to elicit beneficial effects in hypoglycemic actions in vivo and in vitro; however, the data remain conflicting. Many pharmaceuticals commonly used today are structurally derived from natural compounds from traditional medicinal plants. Botanicals that are most frequently used to help manage blood glucose include: bitter melon (Momordica charantia), fenugreek (Trigonella foenum graecum), gurmar (Gymnema sylvestre), ivy gourd (Coccinia indica), nopal (Opuntia spp.), ginseng, Russian tarragon (Artemisia dracunculus), cinnamon (Cinnamomum cassia), psyllium (Plantago ovata), and garlic (Allium sativum). In majority of the herbal products and secondary metabolites used in treating diabetes, the mechanisms of action involve regulation of insulin signaling pathways, translocation of GLUT-4 receptor and/or activation the PPARγ. Several flavonoids inhibit glucose absorption by inhibiting intestinal α-amylase and α-glucosidase. In-depth studies to validate the efficacies and safeties of extracts of these traditional medicinal plants are needed, and large, well designed, clinical studies need to be carried out before the use of such preparations can be recommended for treatment and/or prevention of diabetes. The main focus of this review is to describe what we know to date of the active compounds in these, along with their glucose-lowering mechanisms, which are either through insulin-mimicking activity or enhanced glucose uptake.

Natural antioxidants in the treatment and prevention of diabetic nephropathy; a potential approach that warrants clinical trials

Diabetic nephropathy is the major cause of end-stage renal disease and effective and new therapeutic approaches are needed in diabetic nephropathy and chronic kidney diseases. Oxidative stress and inflammatory process are important factors contributing to kidney damage by increasing production of oxidants. KEAP1/Nrf2/ARE pathway regulates the transcription of many antioxidant genes and modulation of the pathway up regulates antioxidants. NFB controls the expression of genes involved in the inflammatory response. Natural substances have antioxidant and anti-inflammatory activities and have an impact on NFB and KEAP1/Nrf2/ARE pathways. The preclinical studies explored the effectiveness of whole herbs, plants or seeds and their active ingredients in established diabetic nephropathy. They ameliorate oxidative stress induced kidney damage, enhance antioxidant system, and decrease inflammatory process and fibrosis; most likely by activating KEAP1/Nrf2/ARE pathway and by deactivating NFB pathway. Whole natural products contain balanced antioxidants that might work synergistically to induce beneficial therapeutic outcome. In this context, more clinical studies involving whole plants or herbal products or mixtures of different herbs and plants and their active ingredients might change our strategies for the management of diabetic nephropathy. The natural products might be useful as preventive interventions and studies are required in this field.

Elevated cardiac 3-deoxyglucosone, a highly reactive intermediate in glycation reaction, in doxorubicin-induced cardiotoxicity in rats

3-Deoxyglucosone (3-DG) is a highly reactive carbonyl intermediate in glycation reaction (also known as Maillard reaction) and plays an important role in diabetic complications. We investigated the potential involvement of 3-DG in doxorubicin (DXR)-induced cardiotoxicity. Male Crl:CD(SD) rats received intravenous injections of DXR at 2mg/kg, once weekly, for 6 weeks, with/without daily intraperitoneal treatment with 3-DG scavenging agents, i.e., aminoguanidine (AG, 25mg/kg/day) and pyridoxamine (PM, 60mg/kg/day). Cardiac levels of 3-DG, thiobarbituric acid reactive substances (TBARS), fructosamine, and pentosidine, plasma glucose levels and cardiac troponin I (cTnI), echocardiography, and histopathology were assessed at 4 and 6 weeks after treatment. Cardiac 3-DG levels were significantly increased by DXR treatment at 4 and 6 weeks. Cardiac fructosamine levels and plasma glucose were not altered by DXR; however, TBARS levels in the heart were significantly increased at 4 and 6 weeks, suggesting that the enhanced generation of 3-DG is not attributed to any abnormal glycemic status, but may be related to oxidative stress by DXR. An advanced glycation end-product, pentosidine, was significantly increased by DXR treatment at 6 weeks. Intervention by AG and PM ameliorated the DXR-induced echocardiographic abnormalities, increased cTnI in plasma, and histopathological lesion as well as normalizing the elevation of 3-DG and pentosidine levels. These results suggest that 3-DG is generated by DXR and involved, at least in part, in the pathogenesis of DXR-cardiotoxicity through glycation reaction.

New Pathogenic Concepts and Therapeutic Approaches to Oxidative Stress in Chronic Kidney Disease

In chronic kidney disease inflammatory processes and stimulation of immune cells result in overproduction of free radicals. In combination with a reduced antioxidant capacity this causes oxidative stress. This review focuses on current pathogenic concepts of oxidative stress for the decline of kidney function and development of cardiovascular complications. We discuss the impact of mitochondrial alterations and dysfunction, a pathogenic role for hyperuricemia, and disturbances of vitamin D metabolism and signal transduction. Recent antioxidant therapy options including the use of vitamin D and pharmacologic therapies for hyperuricemia are discussed. Finally, we review some new therapy options in diabetic nephropathy including antidiabetic agents (noninsulin dependent), plant antioxidants, and food components as alternative antioxidant therapies.

Garlic Attenuates Plasma and Kidney ACE-1 and AngII Modulations in Early Streptozotocin-Induced Diabetic Rats: Renal Clearance and Blood Pressure Implications

Raw garlic aqueous extract (GE) has ameliorative actions on the renin-angiotensin system in type-1 diabetes mellitus (DM); however its effects on plasma and kidney angiotensin I converting enzyme type-1 (ACE-1) and angiotensin II (AngII) require further elucidation. This study investigated the effect of GE on plasma and kidney ACE-1 and AngII concentrations and in relation to systemic and renal clearance indicators significant to blood pressure (BP) homeostasis in early streptozotocin- (STZ-) induced type-1 DM. Normal rats (n = 10) received 0.5 mL normal saline (NR/NS), diabetic rats (n = 10) received 0.5 mL NS (DR/NS), and treated diabetic rats (n = 10) received 50 mg/0.1 mL/100 g body weight GE (DR/GE) as daily intraperitoneal injections for 8 weeks. Compared to NR/NS, DR/NS showed a significant increase in plasma ACE-1 and AngII and conversely a decrease in kidney ACE-1 and AngII. These changes were associated with an increase in BP and clearance functions. Alternatively and compared to DR/NS, DR/GE showed normalization or attenuation in plasma and kidney ACE-1 and AngII. These GE induced rectifications were associated with moderation in BP elevation and renal clearance functions. Garlic attenuates modulations in plasma and kidney ACE-1 and AngII, in addition to BP and renal clearance function in type-1 DM.