Trigonelline ameliorates diabetic hypertensive nephropathy by suppression of oxidative stress in kidney and reduction in renal cell apoptosis and fibrosis in streptozotocin induced neonatal diabetic (nSTZ) rats

The Protective Effect of Vitexin on Hypertensive Nephropathy Rats

INTRODUCTION

Vitexin is a natural flavonoid compound extracted from Vitex leaves or seeds, exhibiting various pharmacological activities including anticancer, antihypertensive, anti-inflammatory, and spasmolytic effects. However, its protective effects on hypertensive nephropathy (HN) and the underlying mechanisms remain unclear.

METHODS

Spontaneous hypertension rats were fed a high-sugar and high-fat diet for 8 weeks to induce the disease HN model. From the 5th week, the rats were administered vitexin via gavage. Blood pressure was measured biweekly using the tail-cuff method. Histopathological changes were assessed using HE staining, and biochemical analyses were performed to evaluate the effects of vitexin on HN rats. The underlying mechanisms of vitexin treatment were investigated through western blotting.

RESULTS

The data demonstrated that vitexin significantly lowered systolic, diastolic, and mean arterial pressures and ameliorated histopathological changes in HN rats. Biochemical analyses revealed that vitexin reduced the levels of creatinine (Cr), blood urea nitrogen (BUN), total cholesterol (TC), triglycerides (TG), total protein (TP), low-density lipoprotein cholesterol (LDL-C), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA), and advanced glycation end products (AGEs), while increasing the levels of albumin (ALB) and superoxide dismutase (SOD). Western blotting results indicated that vitexin treatment decreased the expression of TNF-α, IL-6, and nuclear factor kappa-B (NF-κB), while increasing the expression of SOD.

CONCLUSION

The findings of this study suggest that vitexin exerts protective effects against HN, providing pharmacological evidence for its potential use in HN treatment.

Nephroprotective effects of Aralia taibaiensis in a high-fat diet-streptozotocin rat model of diabetic nephropathy

Diabetic nephropathy (DN) has emerged as the foremost cause of end-stage renal disease (ESRD) globally. Endoplasmic reticulum (ER) stress plays a critical role in DN progression. Triterpenoid saponin from Aralia taibaiensis (sAT) has been reported to possess anti-diabetic and anti-oxidant effects. The aim of this study was to examine the influence of sAT on DN treatment and elucidate potential underlying mechanisms. A high-fat diet (HFD) and Streptozotocin (STZ) were employed to induce DN in male Sprague Dawley (SD) rats which were subsequently treated with varying concentrations of sAT for 8 weeks. Our findings reveal that different doses of sAT significantly mitigated hyperglycemia, reduced urinary albumin excretion, and decreased plasma creatinine and blood urea nitrogen levels in DN rats. Moreover, sAT administration improved body weight, alleviated renal fibrosis and histopathological changes in the diabetic kidneys. Notably, sAT treatment partially restored increased Bax expression and decreased Bcl-2 expression. Additionally, sAT inhibited ER stress-related proteins, including GRP78, p-PERK, ATF4 and CHOP in kidneys of DN rats. These results suggest that sAT ameliorated experimental diabetic nephropathy, at least in part, through ER stress pathway. These findings provide a scientific basis for the potential development of sAT as a therapeutic agent for DN treatment.

Pharmacological Activities, Therapeutic Effects, and Mechanistic Actions of Trigonelline

Trigonelline (TRG) is a natural polar hydrophilic alkaloid that is found in many plants such as green coffee beans and fenugreek seeds. TRG potentially acts on multiple molecular targets, including nuclear factor erythroid 2-related factor 2 (Nrf2), peroxisome proliferator-activated receptor γ, glycogen synthase kinase, tyrosinase, nerve growth factor, estrogen receptor, amyloid-β peptide, and several neurotransmitter receptors. In this review, we systematically summarize the pharmacological activities, medicinal properties, and mechanistic actions of TRG as a potential therapeutic agent. Mechanistically, TRG can facilitate the maintenance and restoration of the metabolic homeostasis of glucose and lipids. It can counteract inflammatory constituents at multiple levels by hampering pro-inflammatory factor release, alleviating inflammatory propagation, and attenuating tissue injury. It concurrently modulates oxidative stress by the blockage of the detrimental Nrf2 pathway when autophagy is impaired. Therefore, it exerts diverse therapeutic effects on a variety of pathological conditions associated with chronic metabolic diseases and age-related disorders. It shows multidimensional effects, including neuroprotection from neurodegenerative disorders and diabetic peripheral neuropathy, neuromodulation, mitigation of cardiovascular disorders, skin diseases, diabetic mellitus, liver and kidney injuries, and anti-pathogen and anti-tumor activities. Further validations are required to define its specific targeting molecules, dissect the underlying mechanistic networks, and corroborate its efficacy in clinical trials.

Huaju Xiaoji Formula Regulates ERS-lncMGC/miRNA to Enhance the Renal Function of Hypertensive Diabetic Mice with Nephropathy

Background

Better therapeutic drugs are required for treating hypertensive diabetic nephropathy. In our previous study, the Huaju Xiaoji (HJXJ) formula promoted the renal function of patients with diabetes and hypertensive nephropathy. In this study, we investigated the therapeutic effect and regulation mechanism of HJXJ in hypertensive diabetic mice with nephropathy.

Methods

We constructed a mouse hypertensive diabetic nephropathy (HDN) model by treating mice with streptozotocin (STZ) and nomega-nitro-L-arginine methyl ester (LNAME). We also constructed a human glomerular mesangial cell (HGMC) model that was induced by high doses of sugar (30 mmol/mL) and TGFβ1 (5 ng/mL). Pathological changes were evaluated by hematoxylin and eosin (H&E) staining, periodic acid Schiff (PAS) staining, and Masson staining. The fibrosis-related molecules (TGFβ1, fibronectin, laminin, COL I, COL IV, α-SMA, and p-smad2/3) were detected by enzyme-linked immunosorbent assay (ELISA). The mRNA levels and protein expression of endoplasmic reticulum stress, fibrosis molecules, and their downstream molecules were assessed using qPCR and Western blotting assays.

Results

Administering HJXJ promoted the renal function of HDN mice. HJXJ reduced the expression of ER stress makers (CHOP and GRP78) and lncMGC, miR379, miR494, miR495, miR377, CUGBP2, CPEB4, EDEM3, and ATF3 in HDN mice and model HGMCs. The positive control drugs (dapagliflozin and valsartan) also showed similar effects after treatment with HJXJ. Additionally, in model HGMCs, the overexpression of CHOP or lncMGC decreased the effects of HJXJ-M on the level of fibrosis molecules and downstream target molecules.

Conclusion

In this study, we showed that the HJXJ formula may regulate ERS-lncMGC/miRNA to enhance renal function in hypertensive diabetic mice with nephropathy. This study may act as a reference for further investigating whether combining HJXJ with other drugs can enhance its therapeutic effect. The findings of this study might provide new insights into the clinical treatment of hypertensive diabetic nephropathy with HJXJ.

Trigonelline mitigates bleomycin-induced pulmonary inflammation and fibrosis: Insight into NLRP3 inflammasome and SPHK1/S1P/Hippo signaling modulation

AIMS

Pulmonary fibrosis (PF) is a chronic interstitial lung disease with an increasing incidence following the COVID-19 outbreak. Pirfenidone (Pirf), an FDA-approved pulmonary anti-fibrotic drug, is poorly tolerated and exhibits limited efficacy. Trigonelline (Trig) is a natural plant alkaloid with diverse pharmacological actions. We investigated the underlying prophylactic and therapeutic mechanisms of Trig in ameliorating bleomycin (BLM)-induced PF and the possible synergistic antifibrotic activity of Pirf via its combination with Trig.

MATERIALS AND METHODS

A single dose of BLM was administered intratracheally to male Sprague-Dawley rats for PF induction. In the prophylactic study, Trig was given orally 3 days before BLM and then for 28 days. In the therapeutic study, Trig and/or Pirf were given orally from day 8 after BLM until the 28th day. Biochemical assay, histopathology, qRT-PCR, ELISA, and immunohistochemistry were performed on lung tissues.

KEY FINDINGS

Trig prophylactically and therapeutically mitigated the inflammatory process via targeting NF-κB/NLRP3/IL-1β signaling. Trig activated the autophagy process which in turn attenuated alveolar epithelial cells apoptosis and senescence. Remarkably, Trig attenuated lung SPHK1/S1P axis and its downstream Hippo targets, YAP-1, and TAZ, with a parallel decrease in YAP/TAZ profibrotic genes. Interestingly, Trig upregulated lung miR-375 and miR-27a expression. Consequently, epithelial-mesenchymal transition in lung tissues was reversed upon Trig administration. These results were simultaneously associated with profound improvement in lung histological alterations.

SIGNIFICANCE

The current study verifies Trig's prophylactic and antifibrotic effects against BLM-induced PF via targeting multiple signaling. Trig and Pirf combination may be a promising approach to synergize Pirf antifibrotic effect.

Trigonelline inhibits tubular epithelial-mesenchymal transformation in diabetic kidney disease via targeting Smad7

OBJECTIVES

Diabetic kidney disease (DKD) is a prevalent microvascular complication of diabetes. Inhibiting the epithelial-mesenchymal transition (EMT) of proximal tubule epithelial cells (PTCs) can slow down renal fibrosis. Trigonelline (TRL), an alkaloid isolated from the fenugreek, has demonstrated therapeutic effects on diabetes and its complications. Nevertheless, the underlying mechanisms for the effects of TRL are still obscure. The present study was aimed to evaluate the treatment of TRL against DKD and explore the potential mechanisms.

METHODS

The db/db mice were used as a spontaneous model of DKD and TRL solution was administered by daily gavage for 8 weeks. Indicators associated with glucose metabolism, renal function and urinary albumin were tested. Renal fibrosis in diabetic mice was evaluated by histopathological staining. Kidney transcriptomics was performed after confirming therapeutic effects of TRL on DKD mice. Molecular biology techniques and in vitro experiments were utilized for final mechanism verification.

RESULTS

Biochemical tests revealed that TRL ameliorated renal damage and reduced microalbuminuria in DKD mice. TRL exhibited a protective effect on PTCs, effectively mitigating tubular EMT and renal fibrosis in diabetic kidneys. Transcriptomics analysis indicated that TRL may target Smad7, an inhibitor of TGF-β1 signaling, to alleviate fibrosis. Furthermore, in vitro experiments validated that silencing Smad7 abolished the therapeutic effect of TRL.

CONCLUSION

Our findings indicate that TRL can alleviate tubular epithelial-mesenchymal transition and renal fibrosis in db/db mice by upregulating Smad7 in PTCs, suggesting that TRL is a promising medicine against DKD.

Metabolomics for the identification of early biomarkers of nephrotoxicity in a mouse model of cisplatin-induced acute kidney injury

BACKGROUND AND PURPOSE

Cisplatin-induced nephrotoxicity manifests as acute kidney injury (AKI) in approximately one third of patients receiving cisplatin therapy. Current measures of AKI are inadequate in detecting AKI prior to significant renal injury, and better biomarkers are needed for early diagnosis of cisplatin-induced AKI.

EXPERIMENTAL APPROACH

C57BL/6 and FVB/N mice were treated with a single intraperitoneal injection of cisplatin (15 mg kg-1) or saline. Plasma, urine, and kidney samples were collected prior to cisplatin injection and 24-, 48-, 72-, and 96-hours following cisplatin injection. Untargeted metabolomics was employed using liquid chromatography-mass spectrometry to identify early diagnostic biomarkers for cisplatin nephrotoxicity.

PRINCIPAL RESULTS

There was clear metabolic discrimination between saline and cisplatin-treated mice at all timepoints (day 1 to day 4). In total, 26 plasma, urine, and kidney metabolites were identified as exhibiting early alterations following cisplatin treatment. Several of the metabolites showing early alterations were associated with mitochondrial function and energetics, including intermediates of the tricarboxylic acid cycle, regulators of mitochondrial function and indicators of fatty acid β-oxidation dysfunction. Furthermore, several metabolites were derived from the gut microbiome.

MAJOR CONCLUSIONS

Our results highlight the detrimental effects of cisplatin on mitochondrial function and demonstrate potential involvement of the gut microbiome in the pathophysiology of cisplatin-induced AKI. We provide a panel of metabolites to guide future clinical studies of cisplatin-induced AKI and provide insight into potential mechanisms behind cisplatin nephrotoxicity.

The neuroprotective and antidiabetic effects of trigonelline: A review of signaling pathways and molecular mechanisms

The global epidemic of diabetes has brought heavy pressure on public health. New effective anti-diabetes strategies are urgently needed. Trigonelline is the main component of fenugreek, which has been proved to have a good therapeutic effect on diabetes and diabetic complications. Trigonelline achieves amelioration of diabetes, the mechanisms of which include the modulation of insulin secretion, a reduction in oxidative stress, and the improvement of glucose tolerance and insulin resistance. Besides, trigonelline has been reported to be a neuroprotective agent against many neurologic diseases including Alzheimer's disease, Parkinson's disease, stroke, and depression. Concerning the potential therapeutic effects of trigonelline, comprehensive clinical trials are warranted to evaluate this valuable molecule.

Anti-apoptotic effect of HeidihuangWan in renal tubular epithelial cells via PI3K/Akt/mTOR signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Heidihuang Wan (HDHW) is a classic Chinese herbal formula, which was first recorded in the "Suwen Bingji Qiyi Baoming Collection" written by Liu Wansu during the Jin Dynasty (1115-1234 AD). It is commonly used clinically for the treatment of kidney diseases and its curative effect is stable. Previous animal experiments have confirmed that HDHW can effectively improve renal fibrosis. However, the underlying pharmacological mechanism remains unclear.

AIMS OF THIS STUDY

Renal tubular epithelial cell (RTEC) apoptosis is one of the main pathological features of renal fibrosis. This study aimed to observe the effect and underlying mechanism of HDHW on the apoptosis of RTECs to further explore the pathological mechanism of HDHW against renal fibrosis.

MATERIALS AND METHODS

We examined the HDHW composition in rat serum. In vitro, we first screened out the optimal intervention concentration of HDHW on RTECs using the MTT assay. Hypoxia/reoxygenation was then used to induce apoptosis of RTECs (H/R-RTECs), which were divided into H/R-RTEC, astragaloside IV (positive control), HDHW, and RTECs groups. After 48 h of drug intervention, apoptosis of RTECs was detected using flow cytometry and protein expression was detected by western blotting. The 5/6 nephrectomy rat model was constructed and divided into the normal control, 5/6 nephrectomy, HDHW, and astragaloside IV groups. After 8 weeks of treatment, TUNEL staining was used to detect cell apoptosis, and western blotting was used to detect protein expression.

RESULTS

HDHW downregulated the expression of pro-apoptotic proteins Bax and Caspase3, up-regulated the expression of anti-apoptotic protein Bcl-2, activated the PI3K/Akt/mTOR signaling pathway, and reversed the early apoptosis of RTECs, thereby resisting the apoptosis of RTECs.

CONCLUSION

HDHW inhibits apoptosis of RTECs by modulating the PI3K/Akt/mTOR signaling pathway. This study provides experimental evidence for the anti-fibrotic effect of HDHW on the kidneys and partially elucidates its pharmacological mechanism of action.

A natural products solution to diabetic nephropathy therapy

Diabetic nephropathy is one of the most common complications in diabetes. It has been shown to be the leading cause of end-stage renal disease. However, due to their complex pathological mechanisms, effective therapeutic drugs other than angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), which have been used for 20 years, have not been developed so far. Recent studies have shown that diabetic nephropathy is characterized by multiple signalling pathways and multiple targets, including inflammation, apoptosis, pyroptosis, autophagy, oxidative stress, endoplasmic reticulum stress and their interactions. It definitely exacerbates the difficulty of therapy, but at the same time it also brings out the chance for natural products treatment. In the most recent two decades, a large number of natural products have displayed their potential in preclinical studies and a few compounds are under invetigation in clinical trials. Hence, many compounds targeting these singals have been emerged as a comprehensive blueprint for treating strategy of diabetic nephropathy. This review focuses on the cellular and molecular mechanisms of natural prouducts that alleviate this condition, including preclinical studies and clinical trials, which will provide new insights into the treatment of diabetic nephropathy and suggest novel ideas for new drug development.

Syringic Acid Ameliorates Cardiac, Hepatic, Renal and Neuronal Damage Induced by Chronic Hyperglycaemia in Wistar Rats: A Behavioural, Biochemical and Histological Analysis

This study investigated the effects of syringic acid (SA) on renal, cardiac, hepatic, and neuronal diabetic complications in streptozotocin-induced neonatal (nSTZ) diabetic rats. STZ (110 mg/kg i.p) was injected into Wistar rat neonates as a split dose (second and third postnatal day). Diabetes mellitus was diagnosed in adults by measuring fasting blood glucose levels, urine volume, and food and water intake. The treatment of SA (25 mg/kg, 50 mg/kg p.o) was given from the 8th to 18th postnatal week. To assess the development of diabetic complications and the effect of therapy, biochemical indicators in serum and behavioural parameters were recorded at specific intervals during the study period. SA (25 mg/kg, 50 mg/kg p.o) treatment reduced hyperglycaemia, polydipsia, polyphagia, polyuria, relative organ weight, cardiac hypertrophic indices, inflammatory markers, cell injury markers, glycated haemoglobin, histopathological score, and oxidative stress, and increased Na/K ATPase activity. These findings suggest that SA might significantly alleviate diabetic complications and/or renal, neuronal, cardiac, and hepatic damage in nSTZ diabetic rats.

Trigonelline induces autophagy to protect mesangial cells in response to high glucose via activating the miR-5189-5p-AMPK pathway

BACKGROUND

Diabetic nephropathy (DN) is a primary cause of end-stage renal disease. Increasing evidence indicates that microRNAs (miRNAs) are involved in DN pathogenesis. Trigonelline (TRL) has been shown to lower blood sugar and cholesterol levels, promote nerve regeneration, and exert anti-cancer and sedative properties.

METHOD

The effect of TRL on human mesangial cell (HMC) growth was assessed using the MTT assay. Differentially expressed miRNAs were validated using real-time quantitative polymerase chain reaction (real-time PCR). Bioinformatics, cell transfection, and Western blot analyses were utilized to confirm the binding of miR-5189-5p to HIF1AN. The effects of miR-5189-5 expression on cell proliferation were also assessed. Western blot analysis was used to determine the activation of multiple signaling molecules including phosphorylated-(p)-AMPK, SIRT1, LC3B, p62, and Beclin-1 in the autophagy pathway.

RESULTS

TRL improved proliferation, increased the expression of miR-5189-5p, reduced HIF1AN, and restored the inhibition of autophagy in HMCs induced by high glucose. MiR-5189-5p mimics inhibited HIF1AN expression, and the miR-5189-5p inhibitor increased HIF1AN expression. MiR-5189-5p mimics significantly improved the proliferation of HMCs induced by high glucose, reduced the relative protein expression of p-AMPK, SIRT1, LC3B, and Beclin-1, and significantly increased the relative protein expression of p62.

CONCLUSION

We showed that TRL up-regulated miR-5189-5p expression, activated the AMPK pathway, and activated autophagy in HMCs. Our study demonstrates that TRL could be a new treatment strategy to protect mesangial cells in response to high glucose.

Comparison between the Antioxidant and Antidiabetic Activity of Fenugreek and Buckthorn in Streptozotocin-Induced Diabetic Male Rats

This study is aimed at comparing the antidiabetic and antioxidant potential of fenugreek and buckthorn which are commonly used in modulating diabetes in the Middle East. In this study, the antioxidant and antidiabetic activity of the aqueous extracts of the leaf and seed of fenugreek and buckthorn was tested in streptozotocin-induced diabetic male rats fed with a fat-rich diet for 8 weeks. Thirty-six male albino rats were divided into 6 groups (n = 6); the 1st group was the negative control. Diabetes was induced in the other 30 rats using streptozotocin, which were then divided into 5 groups; the 2nd was the untreated positive diabetic group, the 3rd was treated with fenugreek leaf aqueous extract, the 4th was treated with the fenugreek seed aqueous extract, the 5th was treated with buckthorn leaf aqueous extract, and the 6th was treated with buckthorn seed aqueous extract. The positive control group showed an increase in blood sugar, glycated hemoglobin, liver function enzymes, lactate dehydrogenase, kidney indices, total cholesterol, triglycerides, low- and very-low-density lipoprotein, immunoglobulins, and lipid peroxidation and a decrease in high-density lipoprotein, albumin, and antioxidant activity. The histology of the liver and testes showed severe histopathological alterations. Rats of groups 4-6 that were treated with the aqueous extract of the leaf and seed extract of fenugreek and buckthorn showed improvement of all biochemical and histopathological parameters. The seed extract of fenugreek and buckthorn showed more antioxidant activity than their leaves.

Vitexin, a fenugreek glycoside, ameliorated obesity-induced diabetic nephropathy via modulation of NF-κB/IkBα and AMPK/ACC pathways in mice

Obesity is one of the most critical risk factors for diabetes mellitus and plays a significant role in diabetic nephropathy (DN). The present investigation aimed to evaluate the possible mechanism of action of vitexin on obesity-induced DN in a high-fat diet (HFD)-fed experimental C57BL/6 mice model. Obesity was induced in male C57BL/6 mice by chronic administration of HFD, and mice were concomitantly treated with vitexin (15, 30, and 60 mg/kg, p.o.). HFD-induced increased renal oxido-nitrosative stress and proinflammatory cytokine levels were significantly inhibited by vitexin. The Western blot analysis suggested that alteration in renal NF-κB, IκBα, nephrin, AMPK, and ACC phosphorylation levels was effectively restored by vitexin treatment. Histological aberration induced in renal tissue after chronic administration of HFD was also reduced by vitexin. In conclusion, vitexin suppressed the progression of obesity-induced DN via modulation of NF-κB/IkBα and AMPK/ACC pathways in an experimental model of HFD-induced DN in C57BL/6J mice.

Effect of Dapagliflozin on Urine Metabolome in Patients with Type 2 Diabetes

CONTEXT

Inhibitors of sodium-glucose cotransporters-2 have cardio- and renoprotective properties. However, the underlying mechanisms remain indeterminate.

OBJECTIVE

To evaluate the effect of dapagliflozin on renal metabolism assessed by urine metabolome analysis in patients with type 2 diabetes.

DESIGN

Prospective cohort study.

SETTING

Outpatient diabetes clinic of a tertiary academic center.

PATIENTS

Eighty patients with hemoglobin A1c > 7% on metformin monotherapy were prospectively enrolled.

INTERVENTION

Fifty patients were treated with dapagliflozin for 3 months. To exclude that the changes observed in urine metabolome were merely the result of the improvement in glycemia, 30 patients treated with insulin degludec were used for comparison.

MAIN OUTCOME MEASURE

Changes in urine metabolic profile before and after the administration of dapagliflozin and insulin degludec were assessed by proton-nuclear magnetic resonance spectroscopy.

RESULTS

In multivariate analysis urine metabolome was significantly altered by dapagliflozin (R2X = 0.819, R2Y = 0.627, Q2Y = 0.362, and coefficient of variation analysis of variance, P < 0.001) but not insulin. After dapagliflozin, the urine concentrations of ketone bodies, lactate, branched chain amino acids (P < 0.001), betaine, myo-inositol (P < 0001), and N-methylhydantoin (P < 0.005) were significantly increased. Additionally, the urine levels of alanine, creatine, sarcosine, and citrate were also increased (P < 0001, P <0.0001, and P <0.0005, respectively) whereas anserine decreased (P < 0005).

CONCLUSIONS

Dapagliflozin significantly affects urine metabolome in patients with type 2 diabetes in a glucose lowering-independent way. Most of the observed changes can be considered beneficial and may contribute to the renoprotective properties of dapagliflozin.

Ethyl ferulate, a lipophilic phenylpropanoid, prevents diabetes-associated renal injury in rats by amelioration of hyperglycemia-induced oxidative stress via activation of nuclear factor erythroid 2-related factor 2

Diabetic nephropathy affects approximately 20%-40% of diabetes patients worldwide and is the leading cause of end-stage renal failure. Oxidative stress has been identified as a major causative factor in the development and progression of diabetic nephropathy; Nuclear factor erythroid 2-related factor 2 (Nrf2) activation protects the body against oxidative stress by induction of antioxidant enzymes. The renoprotective effect of ethyl ferulate was investigated in diabetes-induced renal injury. Ethyl ferulate was administered orally at three doses (50 mg/kg, 75 mg/kg, and 100 mg/kg). Metformin (500 mg/kg, p.o.) was used as a standard. Ethyl ferulate treatment decreased serum advanced glycation end products, glycosylated hemoglobin (HbA1c) levels, renal oxidative stress, tumor necrosis factor-α (TNF-α) level, and kidney hypertrophy index. It restored serum lipid profile, biomarkers of renal function, and mitigated histopathological signs of renal damage. Immunohistochemistry demonstrated higher Nrf2 protein levels in kidney sections of ethyl ferulate-treated rats. These findings suggest that ethyl ferulate ameliorated hyperglycemia-induced oxidative stress by increasing renal Nrf2 levels, thereby preventing diabetes-induced kidney injury. In conclusion, the present study endorses the usefulness of Nrf2 activators, such as ethyl ferulate, as adjuvant therapy for preventing the diabetic nephropathy. PRACTICAL APPLICATIONS: Ethyl ferulate (ethyl-3-hydroxyl-4-methoxycinnamate), a phenylpropanoid, is a naturally occurring ethyl ester of ferulic acid and is widely present in plants and especially grains, such as rice and maize. Our study has highlighted the renoprotective effect of ethyl ferulate in preventing diabetes-associated renal injury. The observed effect of ethyl ferulate is due to amelioration of diabetes-induced oxidative stress and inflammation, by activation of the Nrf2 pathway. These results indicate the potential of ethyl ferulate as a nutraceutical or adjuvant therapy in prevention of diabetic nephropathy.

Natural Alkaloids and Diabetes Mellitus: A Review

BACKGROUND

The use of herbal therapies for treatment and management of diabetes mellitus and complications associated with this chronic condition is increasing. Plants contain a bounty of phytochemicals that have been proven to be protective by reducing the risk of various ailments and diseases, including alkaloids. Moreover, alkaloids are known to be among the oldest natural products used by humans for highlighting drugs that play crucial roles as therapeutic agents. The reason for this expanding interest and uses of alkaloids as a part of plant natural compounds-based treatments is that a significant proportion of diabetic patients do not respond very well to conventional therapeutic medication. Furthermore, other explanations to this fact are the cost of medication, side-effects, accessibility, and availability of health facilities and drugs and the inefficiency of these medicines in certain cases.

OBJECTIVE

In this study we aimed to review the literature on the valuable effects of herbs and plants and their isolated alkaloids compounds as medication for management of diabetes, a prevalent risk factor for several other disorders and illnesses.

METHODS

In the current review, PubMed, ScienceDirect, Springer and google scholar databases were used and the criterion for inclusion was based on the following keywords and phrases: diabetes, hyperglycemia, complications of diabetes, alkaloids, antidiabetic alkaloids, hypoglycemic alkaloids, alkaloids and complications of diabetes mellitus, mechanisms of action and alkaloids.

RESULTS

In the current review, we demonstrate that alkaloids in the form of extracts and isolated molecules obtained from a large variety of species demonstrated their efficiency for improving raises in blood glucose either in animal models via experimental studies or in human subjects via clinical trials. Medicinal species as chillies (Capsicum annuum), turmeric (Curcuma longa), barberry (Berberis vulgaris) and cress (Lepidium sativum) are among the most common and therapeutic plants used for controlling diabetes that were the subject of several experimental and clinical investigations. Whereas, isolated alkaloids such as berberine, capsaicin and trigonelline have received more interest in this field. Interestingly, the therapeutic impact of alkaloids against blood glucose pathogenesis is mediated through a variety of signaling cascades and pathways, via inhibiting or stimulating diversity of systems such as inhibition of α-glucosidase enzyme, blockade of PTP- 1B, deactivation of DPP-IV, increasing insulin sensitivity and modulating the oxidative stress.

CONCLUSION

Based on the findings of the present review, alkaloids could be used as preventive and curative agents in the case of endocrine disorders, particularly diabetes and could play a promoting function for the discovery of new antidiabetic agents.

Decaffeinated coffee and its benefits on health: focus on systemic disorders

The current literature has mainly focused on benefits and risks deriving from the consumption of caffeinated coffee and its implications for inflammation, cardiovascular diseases, neurodegenerative disorders, and cancer. Today, data about the role of caffeine in many disorders are controversial and the attention has increasingly focused on decaffeinated coffee and its non-caffeine compounds, which could have mainly beneficial effects. In fact, coffee phenolic compounds not only exhibit well-known antioxidant properties, but they can also antagonize some negative effects of caffeine, for example in inflammatory pathway and in glucose metabolism and homeostasis. In this review, we consider the literature of the last two decades and critically discuss the effects of decaffeinated coffee compounds on systemic disorders, mainly inflammation, cardiovascular diseases, hepatic dysfunctions, and cancer.

Natural Alkaloids Intervening the Insulin Pathway: New Hopes for Anti-Diabetic Agents?

BACKGROUND

Accumulating experimental data supports the capacity of natural compounds to intervene in complicated molecular pathways underlying the pathogenesis of certain human morbidities. Among them, diabetes is now a world's epidemic associated with increased risk of death; thus, the detection of novel anti-diabetic agents and/or adjuvants is of vital importance. Alkaloids represent a diverse group of natural products with a range of therapeutic properties; during the last 20 years, published research on their anti-diabetic capacity has been tremendously increased.

PURPOSE

To discuss current concepts on the anti-diabetic impact of certain alkaloids, with special reference to their molecular targets throughout the insulin-signaling pathway.

METHODOLOGY

Upon in-depth search in the SCOPUS and PUBMED databases, the literature on alkaloids with insulin secretion/sensitization properties was critically reviewed.

RESULTS

In-vitro and in-vivo evidence supports the effect of berberine, trigonelline, piperine, oxymatrine, vindoneline, evodiamine and neferine on insulin-signaling and related cascades in beta-cells, myocytes, adipocytes, hepatocytes and other cells. Associated receptors, kinases, hormones and cytokines, are affected in terms of gene transcription, protein expression, activity and/or phosphorylation. Pathophysiological processes associated with insulin resistance, beta-cell failure, oxidative stress and inflammation, as well as clinical phenotype are also influenced.

DISCUSSION

Growing evidence suggests the ability of specific alkaloids to intervene in the insulin-signal transduction pathway, reverse molecular defects resulting in insulin resistance and glucose intolerance and improve disease complications, in-vitro and in-vivo. Future indepth molecular studies are expected to elucidate their exact mechanism of action, while large clinical trials are urgently needed to assess their potential as anti-diabetic agents.

A Thyroid Hormone-Independent Molecular Fingerprint of 3,5-Diiodothyronine Suggests a Strong Relationship with Coffee Metabolism in Humans

Background: In numerous studies based predominantly on rodent models, administration of 3,5-diiodo-L-thyronine (3,5-T2), a metabolite of the thyroid hormones (TH) thyroxine (T4) and triiodo-L-thyronine (T3), was reported to cause beneficial health effects, including reversal of steatohepatosis and prevention of insulin resistance, in most instances without adverse thyrotoxic side effects. However, the empirical evidence concerning the physiological relevance of endogenously produced 3,5-T2 in humans is comparatively poor. Therefore, to improve the understanding of 3,5-T2-related metabolic processes, we performed a comprehensive metabolomic study relating serum 3,5-T2 concentrations to plasma and urine metabolite levels within a large general population sample. Methods: Serum 3,5-T2 concentrations were determined for 856 participants of the population-based Study of Health in Pomerania-TREND (SHIP-TREND). Plasma and urine metabolome data were generated using mass spectrometry and nuclear magnetic resonance spectroscopy, allowing quantification of 613 and 578 metabolites in plasma and urine, respectively. To detect thyroid function-independent significant 3,5-T2-metabolite associations, linear regression analyses controlling for major confounders, including thyrotropin and free T4, were performed. The same analyses were carried out using a sample of 16 male healthy volunteers treated for 8 weeks with 250 μg/day levothyroxine to induce thyrotoxicosis. Results: The specific molecular fingerprint of 3,5-T2 comprised 15 and 73 significantly associated metabolites in plasma and urine, respectively. Serum 3,5-T2 concentrations were neither associated with classical thyroid function parameters nor altered during experimental thyrotoxicosis. Strikingly, many metabolites related to coffee metabolism, including caffeine and paraxanthine, formed the clearest positively associated molecular signature. Importantly, these associations were replicated in the experimental human thyrotoxicosis model. Conclusion: The molecular fingerprint of 3,5-T2 demonstrates a clear and strong positive association of the serum levels of this TH metabolite with plasma levels of compounds indicating coffee consumption, therefore pointing to the liver as an organ, the metabolism of which is strongly affected by coffee. Furthermore, 3,5-T2 serum concentrations were found not to be directly TH dependent. Considering the beneficial health effects of 3,5-T2 administration observed in animal models and those of coffee consumption demonstrated in large epidemiological studies, one might speculate that coffee-stimulated hepatic 3,5-T2 production or accumulation represents an important molecular link in this connection.

Fenugreek Leaf Extract and Its Gel Formulation Show Activity Against Malassezia furfur

Malassezia spp. are commensal yeasts that can cause cutaneous ailments such as dandruff and seborrheic dermatitis. We sought to develop a cost-effective, herbal formulation for the treatment of cutaneous ailments related to Malassezia spp. Aqueous and ethanolic extracts of fenugreek (Trigonellafoenum-graecum L.) leaves exhibited activity against a clinical isolate and commercial strain of Malassezia furfur. The extracts were also found to be active against other pathogenic fungi such as Aspergillus niger and Candida albicans. Qualitative and quantitative phytochemical evaluation of aqueous extract showed a predominant presence of flavonoids apart from alkaloids, saponins, carbohydrates, phenols, and proteins. Gel formulation of 30% aqueous fenugreek leaf extract was developed and optimized using sodium alginate as a gelling agent. The formulation showed good physicochemical characteristics and retained activity against M. furfur during 3-month accelerated stability studies. Furthermore, the developed herbal gel formulation did not show any irritation or sensitization in New Zealand rabbits after topical application, proving its cutaneous safety. Thus, topical gel formulation containing fenugreek leaf aqueous extract could be a safe and effective herbal treatment for various cutaneous fungal infections, including dandruff.

Trigonelline reduced diabetic nephropathy and insulin resistance in type 2 diabetic rats through peroxisome proliferator-activated receptor-γ

Trigonelline has been reported to serve an important role in cell cycle control, oxidative and ultraviolet stress and DNA methylation. In the present study, the effects of trigonelline were examined on type-2 diabetes mellitus (T2DM)-induced renal dysfunction, and its possible mechanism was investigated. Sprague-Dawley rats were fed with high-fat diet (HFD) for 4 weeks and intraperitoneally injected with 35 mg/kg of streptozotocin for 4 weeks. As a result, trigonelline increased body weight, inhibited the kidney weight/body weight ratio and blood glucose levels, and reduced the levels of blood urea nitrogen, creatinine and albumin in type 2 diabetic rats. In addition, trigonelline also reduced inflammation, oxidative stress and kidney cell apoptosis in T2DM rats. In terms of the molecular mechanisms involved, trigonelline induced the protein expression of peroxisome proliferator-activated receptor (PPAR)-γ and suppressed glucose transporter 4 but suppressed the protein expression of tumor necrosis factor-α and leptin in T2DM rats. The present results demonstrated that trigonelline reduced diabetic nephropathy and insulin resistance in T2DM rats through PPAR-γ.

Trigonelline prevents high cholesterol and high fat diet induced hepatic lipid accumulation and lipo-toxicity in C57BL/6J mice, via restoration of hepatic autophagy

Non-alcoholic fatty liver disease (NAFLD) is often linked with impaired hepatic autophagy. Here, we studied the alterations in hepatocellular autophagy by high cholesterol and high-fat diet (HC-HF) diet in C57BL/6J mice, and by palmitic acid (PA), in AML-12 and HepG2 cells. Further, we analysed role of Trigonelline (TG), a plant alkaloid, in preventing NAFLD, by modulating autophagy. For this, C57BL/6J mice were fed with Standard Chow (SC) or HC-HF diet, with and without TG for 16 weeks. In-vitro; AML-12 cells and HepG2 cells, were exposed to PA with and without TG, for 24 h. Cellular events related to autophagy, lipogenesis, and lipo-toxicity were studied. The HC-HF diet fed mice showed hepatic autophagy blockade, increased triglycerides and steatosis. PA exposure to AML-12 cells and HepG2 cells induced impaired autophagy, ER stress, resulting in lipotoxicity. TG treatment in HC-HF fed mice, restored hepatic autophagy, and prevented steatosis. TG treated AML-12, and HepG2 cells exposed to PA showed autophagy restoration, and reduced lipotoxicity, however, these effects were diminished in Atg7-/- HepG2 cells, and in the presence of chloroquine. This study shows that HC-HF diet-induced impaired autophagy, and steatosis is prevented by TG, which attributes to its novel mechanism in treating NAFLD.

Influence of Loranthus micranthus on hepatic and renal antioxidant status and impaired glycolytic flux in streptozotocin-induced diabetic rats

Background

The use of Loranthus micranthus in folklore medicine for treatment of diabetes and its associated complications is a common practice around the world. The present study investigated this traditional affirmation by in vivo investigation into the effect of L. micranthus leaf extract on hepatic and renal, oxidative status and glucose metabolism in streptozotocin (STZ)-induced diabetic rats.

Methods

Diabetes mellitus was induced in adult male Wistar rats by intraperitoneal injection of STZ (60 mg/kg). The diabetic rats were thereafter treated orally once per day with 5 mg/kg gilbenclamide or L. micranthus leaf extract (100 or 200 mg/kg) and monitored for 14 days. Clinical observations, plasma biochemistry, hormonal profile, oxidative stress parameters, glucose metabolism enzymes and histopathologic examination of the liver and kidney were evaluated to monitor treatment-related effects of L. micranthus leaf extract in STZ-induced diabetic rats.

Results

Loranthus micranthus leaf extract administration significantly ameliorated hyperglycemia-mediated damage by decreasing the blood glucose level (45.9% and 84.7% on days 7 and 14 posttreatment, respectively), enhancing the antioxidant status, inhibiting lipid peroxidation and improving the architecture of the liver and kidney in STZ-induced diabetic rats. Furthermore, intervention of L. micranthus leaf extract restored the liver and kidney function biomarkers and increased the plasma levels of triiodothyronine and thyroxine to normal control in STZ-induced diabetic rats.

Conclusions

The findings from this investigation provide credible scientific support for the traditional use of L. micranthus leaf extract in the treatment of diabetes and its associated complications.

Spice-Derived Bioactive Ingredients: Potential Agents or Food Adjuvant in the Management of Diabetes Mellitus

Spices possess tremendous therapeutic potential including hypoglycemic action, attributed to their bioactive ingredients. However, there is no study that critically reviewed the hypoglycemic potency, safety and the bioavailability of the spice-derived bioactive ingredients (SDBI). Therefore, the aim of the study was to comprehensively review all published studies regarding the hypoglycemic action of SDBI with the purpose to assess whether the ingredients are potential hypoglycemic agents or adjuvant. Factors considered were concentration/dosages used, the extent of blood glucose reduction, the IC50 values, and the safety concern of the SDBI. From the results, cinnamaldehyde, curcumin, diosgenin, thymoquinone (TQ), and trigonelline were showed the most promising effects and hold future potential as hypoglycemic agents. Conclusively, future studies should focus on improving the tissue and cellular bioavailability of the promising SDBI to achieve greater potency. Additionally, clinical trials and toxicity studies are with these SDBI are warranted.

Metabolic Response in Rabbit Urine to Occurrence and Relief of Unilateral Ureteral Obstruction

Ureteral obstruction will lead clinically to hydronephrosis, which may further develop into partial or complete loss of kidney function and even cause permanent histological damage. However, there is little knowledge of metabolic responses during the obstructed process and its recoverability. In this study, a complete unilateral ureteral obstruction (CUUO) model was established in the rabbit, and ¹H NMR-based metabolomic analysis of urine was used to reveal the metabolic perturbations in rabbits caused by CUUO and the metabolic recovery after the CUUO was relieved. Univariate and multivariate statistical analyses were used to identify metabolic characteristics. The gradually decreased levels of 3-hydroxykynurenine, 3-methylhistidine, creatinine, guanidoacetate, meta- and para-hydroxyphenylacetate, and phenylacetylglycine and the gradually increased levels of acetate, alanine, citrate, glycine, lactate, and methionine in urine could be regarded as potential biomarkers for the occurrence and severity of ureteral obstruction. And the reduced levels of 3-methylhistidine, creatinine, guanidoacetate, hippurate, meta-hydroxyphenylacetate, and methylguanidine and the elevated levels of 2-aminoisobutyrate, acetylcholine, citrate, lactate, lysine, valine, and α-ketoglutarate in urine compared with the obstructed level could characterize the metabolic recovery of ureteral obstruction. Our results depicted the disturbed biochemical pathways involved in ureteral obstruction and demonstrated the practicability of recovering renal functions for the patients with severe hydronephrosis in clinical practice by removing causes for obstruction.

Coffee consumption and risk of hypertension: a dose-response meta-analysis of prospective studies

PURPOSE

Recently, a large prospective study provided additional information concerning the debated possible association between habitual coffee consumption and risk of hypertension (HPT). Therefore, we updated the state of knowledge on this issue by carrying out a comprehensive new systematic review of the literature and a meta-analysis of the available relevant studies.

METHODS

We performed a systematic search for prospective studies on general population, published without language restrictions (1966-August 2017). A random-effects dose-response meta-analysis was conducted to combine study specific relative risks (RRs) and 95% confidence intervals. Potential non-linear relation was investigated using restricted cubic splines.

RESULTS

Four studies (196,256 participants, 41,184 diagnosis of HPT) met the inclusion criteria. Coffee intake was assessed by dietary questionnaire. Dose-response meta-analysis showed a non-linear relationship between coffee consumption and risk of HPT (p for non-linearity < 0.001). Whereas the habitual drinking of one or two cups of coffee per day, compared with non-drinking, was not associated with risk of HPT, a significantly protective effect of coffee consumption was found starting from the consumption of three cups of coffee per day (RR = 0.97, 95% CI = 0.94 to 0.99), and was confirmed for greater consumption.

CONCLUSIONS

The results of this analysis indicate that habitual moderate coffee intake is not associated with higher risk of HPT in the general population and that in fact a non-linear inverse dose-response relationship occurs between coffee consumption and risk of HPT.

In vitro antiglycating effect and in vivo neuroprotective activity of Trigonelline in d-galactose induced cognitive impairment

BACKGROUND

Alzheimer's disease (AD) is characterized by amyloid beta (Aβ) plaques, neurofibrillary tangles (NFTs) and cognitive impairment. Literature cites the role of advanced glycation end products (AGEs) in AD due to increased cytotoxicity via oxidative stress. d-galactose (d-gal) induced amnesia stimulates Aβ overproduction via increased oxidative stress and AGEs. Trigonelline (TRG), a naturally occurring alkaloid has been reported to have neuroprotective and antidiabetic properties.

METHODS

Present study assessed the protective effect of TRG against in vitro AGEs formation. Since chronic administration of d-gal increases AGEs, we subsequently investigated the neuroprotective role of TRG (50 and 100 mg/kg as per body weight) against d-gal induced amnesia. Mice were subcutaneously (sc) injected with d-gal (150 mg/kg) for 6 weeks. Behavioral assessments in Morris water maze (MWM) and Y-maze were performed, followed by biochemical estimations to deduce the probable mechanism of action.

RESULTS

In vitro experiments demonstrated that TRG stalled early and late AGEs formation. Chronic d-gal administration significantly impaired cognitive performance in MWM and Y maze, caused marked oxidative damage, elevated the AGEs levels and significantly increased the acetylcholinesterase levels as compared to sham group. TRG (50 and 100 mg/kg) treatment significantly ameliorated cognitive performance, reversed the oxidative damage, decreased AGE levels and caused significant decline in acetylcholine esterase levels as compared to d-gal group.

CONCLUSION

Present study highlights the neuroprotective role of TRG against d-gal induced amnesia due to the antioxidant, antiglycative and anticholinesterase properties.

Alteration of oxidative stress and inflammatory cytokines induces apoptosis in diabetic nephropathy

Diabetic nephropathy (DN) is one of the most significant long‑term complications in terms of morbidity and mortality for diabetic patients; however, the exact cause remains unknown. To address this, the DN model was established, and oxidative stress indexes, including malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH‑Px), and inflammatory cytokines, includinginterleukin‑6 (IL‑6), tumor necrosis factor‑alpha (TNF‑α) and transforming growth factor‑beta (TGF‑β), were examined by ELISA. Renal pathological alterations and cell apoptosis was examined by hematoxylin and eosin and terminal deoxynucleotidyl transferase mediated dUTP nick‑end labeling staining, respectively. The expression levels of B‑cell lymphoma‑2 (Bcl‑2), Bcl‑2 associated X (Bax) and caspase‑3 wereexamined by immunohistochemistry and western blotting. The DN model was correctly established, with lower body weight and the higher blood glucose in the diabetes model group. The expression levels of SOD and GSH‑Px were significantly decreased in the diabetes model group; however, MDA, IL‑6, TNF‑α and TGF‑β were significantly increased. The kidney was severely damaged in the diabetes model group, with inflammatory cell invasion, increasing amount of interstitial matrix and hypertrophy with vacuolar degeneration of renal tubular cells. Cell apoptosis levels were significantly increased, and Bcl‑2 was significantly decreased in the diabetes model group in contrast with that of the sham group; however, Bax and caspase‑3 were significantly increased. It suggested that increased oxidative stress and inflammatory cytokines may enhance the apoptosis levels in DN, and may provide a significant diagnostic reference for DN in diabetes patients.

Rule-Mining for the Early Prediction of Chronic Kidney Disease Based on Metabolomics and Multi-Source Data

¹H Nuclear Magnetic Resonance (NMR)-based metabolic profiling is very promising for the diagnostic of the stages of chronic kidney disease (CKD). Because of the high dimension of NMR spectra datasets and the complex mixture of metabolites in biological samples, the identification of discriminant biomarkers of a disease is challenging. None of the widely used chemometric methods in NMR metabolomics performs a local exhaustive exploration of the data. We developed a descriptive and easily understandable approach that searches for discriminant local phenomena using an original exhaustive rule-mining algorithm in order to predict two groups of patients: 1) patients having low to mild CKD stages with no renal failure and 2) patients having moderate to established CKD stages with renal failure. Our predictive algorithm explores the m-dimensional variable space to capture the local overdensities of the two groups of patients under the form of easily interpretable rules. Afterwards, a L2-penalized logistic regression on the discriminant rules was used to build predictive models of the CKD stages. We explored a complex multi-source dataset that included the clinical, demographic, clinical chemistry, renal pathology and urine metabolomic data of a cohort of 110 patients. Given this multi-source dataset and the complex nature of metabolomic data, we analyzed 1- and 2-dimensional rules in order to integrate the information carried by the interactions between the variables. The results indicated that our local algorithm is a valuable analytical method for the precise characterization of multivariate CKD stage profiles and as efficient as the classical global model using chi2 variable section with an approximately 70% of good classification level. The resulting predictive models predominantly identify urinary metabolites (such as 3-hydroxyisovalerate, carnitine, citrate, dimethylsulfone, creatinine and N-methylnicotinamide) as relevant variables indicating that CKD significantly affects the urinary metabolome. In addition, the simple knowledge of the concentration of urinary metabolites classifies the CKD stage of the patients correctly.

Effects of Trigonelline, an Alkaloid Present in Coffee, on Diabetes-Induced Disorders in the Rat Skeletal System

Diabetes increases bone fracture risk. Trigonelline, an alkaloid with potential antidiabetic activity, is present in considerable amounts in coffee. The aim of the study was to investigate the effects of trigonelline on experimental diabetes-induced disorders in the rat skeletal system. Effects of trigonelline (50 mg/kg p.o. daily for four weeks) were investigated in three-month-old female Wistar rats, which, two weeks before the start of trigonelline administration, received streptozotocin (60 mg/kg i.p.) or streptozotocin after nicotinamide (230 mg/kg i.p.). Serum bone turnover markers, bone mineralization, and mechanical properties were studied. Streptozotocin induced diabetes, with significant worsening of bone mineralization and bone mechanical properties. Streptozotocin after nicotinamide induced slight glycemia increases in first days of experiment only, however worsening of cancellous bone mechanical properties and decreased vertebral bone mineral density (BMD) were demonstrated. Trigonelline decreased bone mineralization and tended to worsen bone mechanical properties in streptozotocin-induced diabetic rats. In nicotinamide/streptozotocin-treated rats, trigonelline significantly increased BMD and tended to improve cancellous bone strength. Trigonelline differentially affected the skeletal system of rats with streptozotocin-induced metabolic disorders, intensifying the osteoporotic changes in streptozotocin-treated rats and favorably affecting bones in the non-hyperglycemic (nicotinamide/streptozotocin-treated) rats. The results indicate that, in certain conditions, trigonelline may damage bone.

Urine Metabolomics by (1)H-NMR Spectroscopy Indicates Associations between Serum 3,5-T2 Concentrations and Intermediary Metabolism in Euthyroid Humans

CONTEXT

3,5-Diiodo-L-thyronine (3,5-T2) is a thyroid hormone metabolite which exhibited versatile effects in rodent models, including the prevention of insulin resistance or hepatic steatosis typically forced by a high-fat diet. With respect to euthyroid humans, we recently observed a putative link between serum 3,5-T2 and glucose but not lipid metabolism.

OBJECTIVE

The aim of the present study was to widely screen the urine metabolome for associations with serum 3,5-T2 concentrations in healthy individuals.

STUDY DESIGN AND METHODS

Urine metabolites of 715 euthyroid participants of the population-based Study of Health in Pomerania (SHIP-TREND) were analyzed by (1)H-NMR spectroscopy. Multinomial logistic and multivariate linear regression models were used to detect associations between urine metabolites and serum 3,5-T2 concentrations.

RESULTS

Serum 3,5-T2 concentrations were positively associated with urinary levels of trigonelline, pyroglutamate, acetone and hippurate. In detail, the odds for intermediate or suppressed serum 3,5-T2 concentrations doubled owing to a 1-standard deviation (SD) decrease in urine trigonelline levels, or increased by 29-50% in relation to a 1-SD decrease in urine pyroglutamate, acetone and hippurate levels.

CONCLUSION

Our findings in humans confirmed the metabolic effects of circulating 3,5-T2 on glucose and lipid metabolism, oxidative stress and enhanced drug metabolism as postulated before based on interventional pharmacological studies in rodents. Of note, 3,5-T2 exhibited a unique urinary metabolic profile distinct from previously published results for the classical thyroid hormones.

Garcinia kola seed ameliorates renal, hepatic, and testicular oxidative damage in streptozotocin-induced diabetic rats

CONTEXT

In Africa, Garcinia kola Heckel (Guttiferae) seed is commonly recommended in folklore medicine for the treatment of diabetes and its associated complications.

OBJECTIVE

The present study evaluated this traditional claim by mechanistic investigation into the effect of G. kola seed administration on renal, hepatic, and testicular oxidative damage in streptozotocin (STZ)-induced diabetic rats.

MATERIALS AND METHODS

Diabetes mellitus was induced in adult male Wistar rats by an intraperitoneal injection of STZ (50 mg/kg). The diabetic rats were thereafter treated orally once per day with G. kola seed (250 mg/kg) and monitored for 14 d. Clinical observations, plasma biochemistry, hormonal profile, oxidative stress indices, sperm characteristics, and histopathological examination of the kidney, liver, and testes were evaluated to monitor treatment-related effects of G. kola seed in STZ-induced diabetic rats.

RESULTS AND DISCUSSION

Garcinia kola seed administration significantly ameliorated hyperglycemia mediated damage by decreasing the blood glucose level (72.8% and 84.6% on the 7th and 14th post-treatment days, respectively), enhancement of the antioxidant system, inhibition of lipid peroxidation, and improving the architecture of the kidney, liver, and testes in STZ-induced diabetic rats. In addition, G. kola seed intervention restored the kidney and liver function biomarkers, the sperm characteristics as well as the plasma levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, triiodothyronine (T3), and thyroxine (T4) to normal in STZ-induced diabetic rats.

CONCLUSION

The findings from this investigation provide persuasive scientific support for the traditional use of G. kola seed in the treatment of diabetes and its associated complications.

Flavonoid rich fraction of Punica granatum improves early diabetic nephropathy by ameliorating proteinuria and disturbed glucose homeostasis in experimental animals

CONTEXT

Different parts of Punica granatum Linn. (Punicaceae) are traditionally used as renal protective agents in the Indian system of medicine. However, there is paucity of information regarding its role in diabetic nephropathy.

OBJECTIVE

The present study investigates the nephroprotective potential of flavonoid-rich fraction of P. granatum leaves in streptozotocin (STZ)-induced early diabetic nephropathy in experimental animals.

MATERIALS AND METHODS

Experimental diabetic nephropathy was induced in Wistar rats by single intraperitonial injection of STZ (65 mg/kg) dissolved in ice cold citrophosphate buffer (pH 4.3). After induction rats were divided into five groups (6 normal; 24 diabetic) and administered with glibenclamide (5 mg/kg) and three dose levels of flavonoid-rich fraction of P. granatum leaves (PGFF), i.e. 50, 100, and 200 mg/kg body weight/day for 28 d. Fasting blood glucose, lipid profile, serum albumin, serum total protein, serum creatinine, blood urea nitrogen (BUN) glycosylated hemoglobin, and biomarkers of kidney oxidative stress were assessed at the end of the treatment period. Urine was analyzed for the measurement of total protein, albumin, and creatinine clearance. Kidney sections were subjected to histopathological study.

RESULTS

Daily oral administration of variable dose levels of PGFF for 28 d normalized various biochemical, metabolic, and histopathological changes in the diabetic rats. PGFF significantly (p < 0.01 and p < 0.05) improved the glycemic status and renal function in diabetic rats as compared with diabetic control rats.

DISCUSSION AND CONCLUSION

The results of our study thus prove the protective effect of PGFF in early diabetic nephropathy by ameliorating proteinuria and disturbed glucose homeostasis in experimental animals.

Physical activity is associated with decreased incidence of chronic kidney disease in type 2 diabetes patients: a retrospective cohort study in Taiwan

AIMS

To assess the effect of physical activity in patients with type 2 diabetes mellitus on prevention of diabetes with chronic kidney disease.

METHODS

This is a cohort study on stratified selected subjects in Taiwan from 2004/01/01 to 2005/12/31. Demographic data, lifestyle factors and clinical characteristics were analyzed for an association with the occurrence of chronic kidney disease. Applicable analysis weights, Stata 11.0, were applied to adjust the design variables for clustering and stratification.

RESULTS

During the two year study period, the univariate Cox proportional hazards model showed significant associations of age, physical activity, and the Charlson comorbidity index (CCI) with chronic kidney disease. Physical activity had a beneficial effect in diabetic subjects with chronic kidney disease (HR: 0.31, p<0.01). Older age and a CCI greater than 2 were both harmful in diabetic subjects with chronic kidney disease (1.06 and 3.44, respectively). The results of a multivariate Cox proportional hazards evaluation model were similar to those of a univariate evaluation model, except that CCI was not significantly different. Moreover, medications for hypertension of diabetic subjects created an increased risk of chronic kidney disease (HR: 5.85 and 3.74, respectively), indicating that the presence of hypertension is a strong risk factor for the progression of chronic kidney disease.

CONCLUSION

In this study, physical activity was not only a healthful lifestyle factor but also a treatment to decrease incidence of chronic kidney disease in diabetic patients.

Trigonelline attenuates the adipocyte differentiation and lipid accumulation in 3T3-L1 cells

Trigonelline is a natural alkaloid mainly found in Trigonella Foenum Graecum (fenugreek) Fabaceae and other edible plants with a variety of medicinal applications. Therefore, we investigated the molecular mechanism of trigonelline (TG) on the inhibition of adipocyte differentiation and lipid accumulation in 3T3-L1 cells. Trigonelline suppressed lipid droplet accumulation in a concentration (75 and 100 μM) dependent manner. Treatment of adipocyte with of TG down regulates the peroxisome proliferator-activated receptor (PPARγ) and CCAAT element binding protein (C/EBP-α) mRNA expression, which leads to further down regulation of other gene such as adiponectin, adipogenin, leptin, resistin and adipocyte fatty acid binding protein (aP2) as compared with respective control cells on 5th and 10th day of differentiation. Further, addition of triognelline along with troglitazone to the adipocyte attenuated the troglitazone effects on PPARγ mediated differentiation and lipid accumulation in 3T3-L1 cells. Trigonelline might compete against troglitazone for its binding to the PPARγ. In addition, adipocyte treated with trigonelline and isoproterenol separately. Isoproterenol, a lipolytic agent which inhibits the fatty acid synthase and GLUT-4 transporter expression via cAMP mediated pathway, we found that similar magnitude response of fatty acid synthase and GLUT-4 transporter expression in trigonelline treated adipocyte. These results suggest that the trigonelline inhibits the adipogenesis by its influences on the expression PPARγ, which leads to subsequent down regulation of PPAR-γ mediated pathway during adipogenesis. Our findings provide key approach to the mechanism underlying the anti-adipogenic activity of trigonelline.

Antihyperglycemic, antihyperlipidemic and antioxidant effects of ethanol and aqueous extracts of Cyclocarya paliurus leaves in type 2 diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Cyclocarya paliurus (CP) Batal., the sole species in its genus and native to China, is a herbal tea, which has been traditionally used in the folk medicine for the treatment of diabetes and hyperlipidemia in China. To evaluate the antihyperglycemic, antihyperlipidemic and antioxidant effects of ethanol and aqueous extracts from CP in high fat diet (HFD) and streptozotocin (STZ) induced diabetic rats.

MATERIALS AND METHODS

Type 2 diabetes was induced in 140 rats by feeding with HFD and high sugar water for 6 weeks and single injection of STZ (30mg/kg, intraperitoneally). CP ethanol extract (CPEE) and aqueous extract (CPAE) at three doses at 2, 4 and 8 g/kg/day were orally administered once daily for four weeks. Blood glucose, serum insulin, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), free fatty acid (FFA), total cholesterol (TC), triglyceride (TG), low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), blood urea nitrogen (BUN), creatinine (CREA) and glycated serum protein (GSP) were examined. The content of total flavonoids and polysaccharides in CPEE and CPAE were assayed by ultraviolet spectrophotometry.

RESULTS

Both CPEE and CPAE increased OGTT, ITT, HDL-C, SOD and GSH-Px, while they decreased FFA, TC, TG, LDL-C, MDA, BUN, CREA and GSP. The amount of total flavonoids was found in CPEE (30.41 mg/g extract), followed by CPAE (6.75 mg/g extract). Similarly, the polysaccharides content (4.13 mg/g extract) was observed in CPAE, while absent in CPEE.

CONCLUSIONS

The results suggested that CPEE and CPAE exhibited the similar antihyperglycemic, antihyperlipidemic and antioxidant effects in type 2 diabetic rats, and there were no significant differences between these two extracts.