Ferulic acid prevents pathological and functional abnormalities of the kidney in Otsuka Long-Evans Tokushima Fatty diabetic rats

Potential utilization of ferulic acid and its derivatives in the management of metabolic diseases and disorders: An insight into mechanisms

Metabolic diseases are abnormal conditions that impair the normal metabolic process, which involves converting food into energy at a cellular level, and cause difficulties like obesity and diabetes. The study aimed to investigate how ferulic acid (FA) and its derivatives could prevent different metabolic diseases and disorders and to understand the specific molecular mechanisms responsible for their therapeutic effects. Information regarding FA associations with metabolic diseases and disorders was compiled from different scientific search engines, including Science Direct, Wiley Online, PubMed, Scopus, Web of Science, Springer Link, and Google Scholar. This review revealed that FA exerts protective effects against metabolic diseases such as diabetes, diabetic retinopathy, neuropathy, nephropathy, cardiomyopathy, obesity, and diabetic hypertension, with beneficial effects on pancreatic cancer. Findings also indicated that FA improves insulin secretion by increasing Ca2+ influx through the L-type Ca2+ channel, thus aiding in diabetes management. Furthermore, FA regulates the activity of inflammatory cytokines (TNF-α, IL-18, and IL-1β) and antioxidant enzymes (CAT, SOD, and GSH-Px) and reduces oxidative stress and inflammation, which are common features of metabolic diseases. FA also affects various signaling pathways, including the MAPK/NF-κB pathways, which play an important role in the progression of diabetic neuropathy and other metabolic disorders. Additionally, FA regulates apoptosis markers (Bcl-2, Bax, and caspase-3) and exerts its protective effects on cellular destruction. In conclusion, FA and its derivatives may act as potential medications for the management of metabolic diseases.

Effect and pharmacological mechanism of Salvia miltiorrhiza and its characteristic extracts on diabetic nephropathy

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic nephropathy (DN) is a severe diabetic microvascular complication with an increasing prevalence rate and lack of effective treatment. Traditional Chinese medicine has been proven to have favorable efficacy on DN, especially Salvia miltiorrhiza Bunge (SM), one of the most critical and conventional herbs in the treatment. Over the past decades, studies have demonstrated that SM is a potential treatment for DN, and the exploration of the underlying mechanism has also received much attention.

AIM OF THIS REVIEW

This review aims to systematically study the efficacy and pharmacological mechanism of SM in the treatment of DN to understand its therapeutic potential more comprehensively.

MATERIALS AND METHODS

Relevant information was sourced from Google Scholar, PubMed, Web of Science, and CNKI databases.

RESULTS

Several clinical trials and systematic reviews have indicated that SM has definite benefits on the kidneys of diabetic patients. And many laboratory studies have further revealed that SM and its characteristic extracts, mainly including salvianolic acids and tanshinones, can exhibit pharmacological activity against DN by the regulation of metabolism, renal hemodynamic, oxidative stress, inflammation, fibrosis, autophagy, et cetera, and several involved signaling pathways, thereby preventing various renal cells from abnormal changes in DN, including endothelial cells, podocytes, epithelial cells, and mesangial cells.

CONCLUSION

As a potential drug for the treatment of DN, SM has multi-component, multi-target, and multi-pathway pharmacological effects. This work will not only verify the satisfactory curative effect of SM in the treatment of DN but also provide helpful insights for the development of new anti-DN drugs and the application of traditional Chinese medicine.

Traditional Chinese medicine for the treatment of immune-related nephropathy: A review

Immune-related nephropathy (IRN) refers to immune-response-mediated glomerulonephritis and is the main cause of end-stage renal failure. The pathogenesis of IRN is not fully understood; therefore, treatment is challenging. Traditional Chinese medicines (TCMs) have potent clinical effects in the treatment of the IRN conditions immunoglobulin A nephropathy, lupus nephropathy, and diabetic nephropathy. The underlying mechanisms mainly include its inhibition of inflammation; improvements to renal interstitial fibrosis, oxidative stress, autophagy, apoptosis; and regulation of immunity. In this review, we summarize the clinical symptoms of the three IRN subtypes and the use of TCM prescriptions, herbs, and bioactive compounds in treating IRN, as well as the potential mechanisms, intending to provide a reference for the future study of TCM as IRN treatments.

New insights into renal lipid dysmetabolism in diabetic kidney disease

Lipid dysmetabolism is one of the main features of diabetes mellitus and manifests by dyslipidemia as well as the ectopic accumulation of lipids in various tissues and organs, including the kidney. Research suggests that impaired cholesterol metabolism, increased lipid uptake or synthesis, increased fatty acid oxidation, lipid droplet accumulation and an imbalance in biologically active sphingolipids (such as ceramide, ceramide-1-phosphate and sphingosine-1-phosphate) contribute to the development of diabetic kidney disease (DKD). Currently, the literature suggests that both quality and quantity of lipids are associated with DKD and contribute to increased reactive oxygen species production, oxidative stress, inflammation, or cell death. Therefore, control of renal lipid dysmetabolism is a very important therapeutic goal, which needs to be archived. This article will review some of the recent advances leading to a better understanding of the mechanisms of dyslipidemia and the role of particular lipids and sphingolipids in DKD.

The ancient Chinese formula Longdan Xiegan Tang improves antipsychotic-induced hyperprolactinemia by repairing the hypothalamic and pituitary TGF-β1 signaling in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Antipsychotics often induce hyperprolactinemia. The transforming growth factor (TGF)-beta1 signaling in the pituitary and hypothalamus inhibits prolactin synthesis and secretion, and its impairment is implicated in neuropsychiatric disorders. Longdan Xiegan Tang (LXT) alone or together with antipsychotics have been used to treat various neuropsychiatric diseases and hyperprolactinemia-associated disorders.

AIM OF THE STUDY

To investigate the effect of LXT on hyperprolactinemia and involvement of the TGF-beta1 signaling.

MATERIALS AND METHODS

Male rats were co-administered with olanzapine (5 mg/kg) and LXT extract (50 and 500 mg/kg) (p.o., × 8 weeks). Plasma concentrations of prolactin and TGF-beta1 were determined by ELISA. Protein expression was analyzed by Western blot.

RESULTS

Treatment of rats with LXT extract suppressed olanzapine-induced increase in plasma prolactin concentration and overexpression of pituitary and hypothalamic prolactin protein. Importantly, LXT restored olanzapine-induced decrease in protein expression of the key components of the TGF-beta1 signaling, TGF-beta1, type II TGF-beta receptor, type I TGF-beta receptor and phosphorylated SMAD3 in the pituitary and hypothalamus. Further, it antagonized downregulation of pituitary and hypothalamic dopamine D2 receptor (D2R) protein level, and inhibited pituitary estrogen receptor (ER) alpha and ERbeta protein expression.

CONCLUSIONS

The present results suggest that LXT ameliorates antipsychotic-induced hyperprolactinemia in rats by repairing the pituitary and hypothalamic TGF-beta1 signaling possibly via D2R, ERs or/and other pathways. Our findings may also provide scientific elucidation for use of the ancient Chinese formula to treat the impaired TGF-beta1 signaling-associated neuropsychiatric disorders.

Extraction of Phenolic Compounds from Tabernaemontana catharinensis Leaves and Their Effect on Oxidative Stress Markers in Diabetic Rats

The aim of this study was to evaluate the most effective extraction condition (temperature, solvent type and time) for recovery of high-value phytochemicals present in the Tabernaemontana catharinensis leaves (TC) and to assess their effect on biochemical parameters in streptozotocin-induced diabetic rats. The extraction of phenolic compounds from TC using a factorial design (FD) 2³, high performance liquid chromatography (HPLC), response surface methodology (RSM) and principal component analysis (PCA) were studied. It was found that the optimal conditions for extraction of phenolics were higher temperature (65 °C) and time (60 min) using ethanol as extractor solvent. In this condition of extraction (A8), total phenolic compounds (TPC) and antioxidant activity (AA) were determined. Additionally, this extract was used to evaluate their effect on antioxidant enzyme activities (superoxide dismutase (SOD) and catalase (CAT)) as well as lipid peroxidation (LP) and protein thiols level (PSH) in the liver and kidneys of normal and diabetic rats. As result, T. catharinensis extract presented TPC content of 23.34 mg EAG/g (equivalent gallic acid) and AA of 34.26 μmol Trolox/g. Phenolic acids (ferulic acid and coumaric acid) and flavonoids (quercetin, rutin and pinocembrin) could be recovered and identified by HPLC. This study indicated an important role of the T. catharinensis extract on free radical inactivation and on the antioxidant defense system in diabetic rats. In fact, the use of T. catharinensis extract restored the normal activity of SOD (p < 0.05) and suppressed malondialdehyde levels in liver and kidney tissues. Thus, the T. catharinensis extract, rich in phenolic compounds, can be responsible for the recover the enzymatic changes in the liver and kidney tissues provoked by diabetes in rats. In addition, the lipid peroxidation rate decreased in the diabetic rats treated with T. catharinensis.

Nephroprotective effect of ferulic acid on gentamicin-induced nephrotoxicity in female rats

Ferulic acid is a kind of phenolic compound that can be found in various fruits and vegetables. This study aims to investigate the effect of ferulic acid on nephrotoxicity induced by gentamicin (GM). In this study, rats were separated into 4 groups such that each containing 8 randomly selected rats: Control group, Ferulic Acid (FA) group, Gentamicin (GM) group and Gentamicin + Ferulic acid (GM + FA) group. Blood samples were collected after 24 hours following the 8-day trial period, and kidneys were taken out for histopathological evaluation. Serum urea, creatinine, uric acid and LDH analyses were performed in autoanalyzer while Malondialdehyde (MDA), Advanced Oxidized Protein Products (AOPP), Glutathione (GSH), Superoxide dismutase (SOD), Catalase (CAT), Interleukin 6 (IL-6), Tumor Necrosis Factor-alpha (TNF-α) analyses were performed in ELISA, and kidney tissues were also examined histopathologically. Urea (p < .001), creatinine (p < .001), MDA (p < .01), AOPP (p < .001), IL-6 (p < .01) and TNF-α (p < .001) levels were found to be statistically and significantly lowered in GM + FA group when compared to GM group. As a result, ferulic acid has reduced the inflammation in nephrotoxicity induced by GM, causing decreased oxidative stress. In this study, anti-inflammatory features of ferulic acid have come to the forefront rather than the antioxidant features. It can be said that ferulic acid reduces nephrotoxic damage and has protective properties for kidneys.

Protective effect of ferulic acid on STZ-induced diabetic nephropathy in rats

Ferulic acid protects against diabetic nephropathy in STZ-induced rats by attenuating oxidative stress, inflammation, fibrosis and podocyte injury.

Anti-hypertensive Effect of Cereal Antioxidant Ferulic Acid and Its Mechanism of Action

Ferulic acid is a simple phenolic acid found mainly in cereals and grains, used as an antioxidant and food preservative. Recent evidence suggests that ferulic acid possess anti-inflammatory, anti-diabetic, anticancer, and cardioprotective properties. Several investigations also have shown that ferulic acid rich food might prevent hypertension. As a potent scavenger of free radicals (ROS, reactive oxygen species), ferulic acid attenuates oxidative stress, which is responsible for lowering elevated blood-pressure through improved endothelial function and increased bioavailability of the nitric oxide in the arterial vasculature. This review article describes the role of ferulic acid in the pathophysiology of vascular dysfunction and hypertension along with highlighted the merit of further scientific and clinical exploration.

Protective effect of the ethanol extract from Ligusticum chuanxiong rhizome against streptozotocin-induced diabetic nephropathy in mice

ETHNOPHARMACOLOGY RELEVANCE

Rhizome of Ligusticum chuanxiong Hort. (Abbreviated as LC) is a frequently prescribed component in plenty of traditional Chinese medicine (TCM) formulas which are used to treat diabetic nephropathy (DN). The aims of the present study are to investigate the protective effect of the ethanol extract of LC rhizome (EEL) against DN in vivo, evaluate its potential mechanism, and find the evidence supporting its enthopharmacological use as an anti-DN agent.

MATERIALS AND METHODS

Hepa 1c1c7 murine hepatoma cells, human breast carcinoma MDA-MB-231 cells, human renal glomerular endothelial cells (HRGEC), and RAW 264.7 murine macrophages were adopted to test the effects of EEL and its active constituents on inhibitions of oxidative stress and inflammation in vitro. A streptozotocin (STZ) -induced DN C57BL/6 mice model was established and used to investigate the preventive effect of EEL against DN in vivo.

RESULTS

EEL demonstrated potential inhibitory effects against oxidative stress and inflammation in vitro. Using a STZ-induced DN mice model, it has been found that EEL treatment significantly prevented STZ-induced increases of urine production, urinary albumin excretion (UAE) and urine albumin-to-creatinine ratio (UACR), and markedly attenuated STZ-induced renal damages (e.g. glomerulosclerosis and fibrosis). The predominant bioactive constituents, Z-ligustilide (LGT), ferulic acid (FA), and tetramethylpyrazine (TMP), were inhibitors of oxidative stress and inflammation through acting with Nrf2 and NF-κB pathways.

CONCLUSIONS

EEL attenuates structural and functional damages of kidney in STZ-induced DN model in vivo, which might be related to the functions of EEL on inhibitions of oxidative stress and inflammation. These finding definitely supports the ethnopharmacological use of LC as an anti-DN agent.

The impact of oat (Avena sativa) consumption on biomarkers of renal function in patients with chronic kidney disease: A parallel randomized clinical trial

BACKGROUND & OBJECTIVE

Animal studies report that oat (Avena sativa L) intake has favorable effects on kidney function. However, the effects of oat consumption have not been assessed in humans. The aim of this study was to examine the impact of oat intake on biomarkers of renal function in patients with chronic kidney disease (CKD).

METHODS

Fifty-two patients with CKD were randomly assigned to a control group (recommended to reduce intake of dietary protein, phosphorus, sodium and potassium) or an oat consumption group (given nutritional recommendations for controls +50 g/day oats). Blood urea nitrogen (BUN), serum creatinine (SCr), urine creatinine, serum albumin, serum potassium, parathyroid hormone (PTH), serum klotho and urine protein concentration were measured at baseline and after an eight-week intervention. Creatinine clearance was calculated using urine creatinine concentration.

RESULTS

Within group analysis showed a significant increase in BUN (P = 0.02) and serum potassium (P = 0.01) and a marginally significant increment in SCr (P = 0.08) among controls. However, changes in the oat group were not significant. In a multivariate adjusted model, we observed a significant difference in change of serum potassium (-0.03 mEq/L for oat group and 0.13 mEq/L for control group; P = 0.01) and a marginally significant difference in change of serum albumin (0.01 g/dl for oat group and -0.08 for control group; P = 0.08) between the two groups. There was no change in PTH concentration.

CONCLUSION

Intake of oats may have a beneficial effect on serum albumin and serum potassium in patients with CKD.

REGISTRATION CODE

Present study registered under IRCT.ir identifier no. IRCT2015050414551N2.

Hydrogen sulfide exhibits cardioprotective effects by decreasing endoplasmic reticulum stress in a diabetic cardiomyopathy rat model

Endoplasmic reticulum (ER) stress is critical in the occurrence and development of diabetic cardiomyopathy (DC). Hydrogen sulfide (H2S) has been found to be the third gaseous signaling molecule with anti‑ER stress effects. Previous studies have shown that H2S acts as a potent inhibitor of fibrosis in the heart of diabetic rats. This study aimed to demonstrate whether H2S exhibits protective effects on the myocardium of streptozotocin (STZ)‑induced diabetic rats by suppressing ER stress. In this study, diabetic models were established by intraperitoneal (i.p.) injection of 40 mg/kg STZ. The STZ‑treated mice were divided into three groups, and subsequently treated with normal saline, 30 µmol/kg or 100 µmol/kg NaHS, i.p., respectively, for 8 weeks. The extent of myocyte hypertrophy was measured using hematoxylin and eosin‑stained sections and collagen components were investigated using immunostaining. The expression of glucose-regulated protein (Grp78), C/EBP‑homologous protein (CHOP) and caspase‑12 in the heart tissue of each group was detected by western blot analysis. It was demonstrated that H2S could improve myocardial hypertrophy and myocardial collagen deposition in diabetic rats. In addition, it could reduce the expression of Grp78, caspase-12 and CHOP. In conclusion, these findings demonstrate that H2S suppresses STZ‑induced ER stress in the hearts of rats, and it may serve as a novel cardioprotective agent for DC.

Review of Herbal Traditional Chinese Medicine for the Treatment of Diabetic Nephropathy

Diabetic nephropathy (DN) is the most serious chronic complications of diabetes; 20-40% of diabetic patients develop into end stage renal disease (ESRD). However, exact pathogenesis of DN is not fully clear and we have great difficulties in curing DN; poor treatment of DN led to high chances of mortality worldwide. A lot of western medicines such as ACEI and ARB have been demonstrated to protect renal function of DN but are not enough to delay or retard the progression of DN; therefore, exploring exact and feasible drug is current research hotspot in medicine. Traditional Chinese medicine (TCM) has been widely used to treat and control diabetes and its complications such as DN in a lot of scientific researches, which will give insights into the mechanism of DN, but they are not enough to reveal all the details. In this paper, we summarize the applications of herbal TCM preparations, single herbal TCM, and/or monomers from herbal TCM in the treatment of DN in the recent 10 years, depicting the renal protective effects and the corresponding mechanism, through which we shed light on the renal protective roles of TCM in DN with a particular focus on the molecular basis of the effect and provide a beneficial supplement to the drug therapy for DN.

Antidiabetic Effects of Simple Phenolic Acids: A Comprehensive Review

Diabetes mellitus (DM) has become a major public health threat across the globe. Current antidiabetic therapies are based on synthetic drugs that very often have side effects. It has been widely acknowledged that diet plays an important role in the management of diabetes. Phenolic acids are widely found in daily foods such as fruits, vegetables, cereals, legumes, and wine and they provide biological, medicinal, and health properties. Simple phenolic acids have been shown to increase glucose uptake and glycogen synthesis, improve glucose and lipid profiles of certain diseases (obesity, cardiovascular diseases, DM, and its complication). The current review is an attempt to list out the antidiabetic effects of simple phenolic acids from medicinal plants and botanical foods.

TGF-β/BMP proteins as therapeutic targets in renal fibrosis. Where have we arrived after 25 years of trials and tribulations?

The understanding of renal fibrosis in chronic kidney disease (CKD) remains as a challenge. More than 10% of the population of developed countries suffer from CKD. Proliferation and activation of myofibroblasts and accumulation of extracellular matrix proteins are the main features of kidney fibrosis, a process in which a large number of cytokines are involved. Targeting cytokines responsible for kidney fibrosis development might be an important strategy to face the problem of CKD. The increasing knowledge of the signaling pathway network of the transforming growth factor beta (TGF-β) superfamily members, such as the profibrotic cytokine TGF-β1 or the bone morphogenetic proteins (BMPs), and their involvement in the regulation of kidney fibrosis, has stimulated numerous research teams to look for potential strategies to inhibit profibrotic cytokines or to enhance the anti-fibrotic actions of other cytokines. The consequence of all these studies is a better understanding of all these canonical (Smad-mediated) and non-canonical signaling pathways. In addition, the different receptors involved for signaling of each cytokine, the different combinations of type I-type II receptors, and the presence and function of co-receptors that can influence the biological response have been also described. However, are these studies leading to suitable strategies to block the appearance and progression of kidney fibrosis? In this review, we offer a critical perspective analyzing the achievements using the most important strategies developed up till now: TGF-β antibodies, chemical inhibitors of TGF-β receptors, miRNAs and signaling pathways and BMP agonists with a potential role as therapeutic molecules against kidney fibrosis.

Ferulic acid improves cardiovascular and kidney structure and function in hypertensive rats

Ferulic acid is a simple phenolic acid commonly present in cereals. In this study, changes in heart and kidney structure and function were measured in young N(ω)-nitro-L-arginine methyl ester (L-NAME)-treated Wistar rats and 10-month-old spontaneously hypertensive rats (SHR) alone and after chronic treatment with ferulic acid (FA; 50 mg·kg⁻¹·d⁻¹; n = 6-10; *P < 0.05). Systolic blood pressures were increased after L-NAME treatment (control 125 ± 2 mm Hg, L-NAME 205 ± 6* mm Hg after 8 weeks) and in SHR (250 ± 2 mm Hg; WKY 149 ± 4 mm Hg). Hypertensive rats developed left ventricular hypertrophy, increased ventricular diastolic stiffness (κ; Wistar, 21.4 ± 1.6; L-NAME, 30.1 ± 0.9*; WKYs, 24.1 ± 0.9; SHR 29.5 ± 0.7) and fibrosis of heart and kidneys. Treatment with ferulic acid reduced systolic blood pressure (L-NAME + FA, 157 ± 4*; SHR + FA 214 ± 8* mm Hg), reduced left ventricular diastolic stiffness (L-NAME + FA, 25.2 ± 0.5*; SHR + FA 26.3 ± 0.5*) and attenuated inflammatory cell infiltration, ferric iron accumulation, and collagen deposition in left ventricles and kidneys. Ferulic acid improved both endothelium-dependent relaxation in isolated thoracic aortic rings and antioxidant status by increasing superoxide dismutase and catalase activity in the heart and kidneys. FA decreased plasma liver enzyme activities and plasma creatinine concentrations. Thus, FA improved the structure and function of the heart, blood vessels, liver, and kidneys in hypertensive rats.

Levels of inflammatory cytokines in type 2 diabetes patients with different urinary albumin excretion rates and their correlation with clinical variables

Although the pathogenetic mechanism of DN has not been elucidated, an inflammatory mechanism has been suggested as a potential contributor. This study was designed to explore the relationship between low-grade inflammation and renal microangiopathy in T2DM. A total of 261 diabetic subjects were divided into three groups according to UAE: a normal albuminuria group, a microalbuminuria group, and a macroalbuminuria group. A control group was also chosen. Levels of hs-CRP, TNF-α, uMCP-1, SAA, SCr, BUN, serum lipid, blood pressure, and HbA1c were measured in all subjects. Compared with the normal controls, levels of hs-CRP, TNF-α, uMCP-1, and SAA in T2DM patients were significantly higher. They were also elevated in the normal albuminuria group, P < 0.05. Compared with the normal albuminuria group, levels of these inflammatory cytokines were significantly higher in the microalbuminuria and macroalbuminuria group, P < 0.01. The macroalbuminuria group also showed higher levels than the microalbuminuria group, P < 0.01. Also they were positively correlated with UAE, SBP, DBP, LDL-C, and TC. We noted no significance correlated with course, TG, or HDL-C. Only TNF-α; was positively correlated with HbA1c. This study revealed the importance of these inflammatory cytokines in DN pathogenesis. Further studies are needed to fully establish the potential of these cytokines as additional biomarkers for the development of DN.

Diabetic nephropathy and antioxidants

CONTEXT

Oxidative stress has crucial role in pathogenesis of diabetic nephropathy (DN). Despite satisfactory results from antioxidant therapy in rodent, antioxidant therapy showed conflicting results in combat with DN in diabetic patients.

EVIDENCE ACQUISITIONS

Directory of Open Access Journals (DOAJ), Google Scholar,Pubmed (NLM), LISTA (EBSCO) and Web of Science have been searched.

RESULTS

Treatment of DN in human are insufficient with rennin angiotensin system (RAS) blockers, so additional agent ought to combine with this management. Meanwhile based on DN pathogenesis and evidences in experimental and human researches, the antioxidants are the best candidate. New multi-property antioxidants may be improved human DN that show high power antioxidant capacity, long half-life time, high permeability to mitochondrion, improve body antioxidants enzymes activity and anti-inflammatory effects.

CONCLUSIONS

Based on this review and our studies on diabetic rats, rosmarinic acid a multi-property antioxidant may be useful in DN patients, but of course, needs to be proven in clinical trials studies.

Ferulsinaic Acid Modulates SOD, GSH, and Antioxidant Enzymes in Diabetic Kidney

The efficacy of Ferulsinaic acid (FA) to modulate the antioxidant enzymes and to reduce oxidative stress induced-diabetic nephropathy (DN) was studied. Rats were fed diets enriched with sucrose (50%, wt/wt), lard (30%, wt/wt), and cholesterol (2.5%, wt/wt) for 8 weeks to induce insulin resistance. After a DN model was induced by streptozotocin; 5, 50 and 500 mg/kg of FA were administrated by oral intragastric intubation for 12 weeks. In FA-treated diabetic rats, glucose, kidney/body weight ratio, creatinine, BUN, albuminurea, and creatinine clearance were significantly decreased compared with non treated diabetic rats. Diabetic rats showed decreased activities of SOD and GSH; increased concentrations of malondialdehyde and IL-6 in the serum and kidney, and increased levels of 8-hydroxy-2'-deoxyguanosine in urine and renal cortex. FA-treatment restored the altered parameters in a dose-dependent manner. The ultra morphologic abnormalities in the kidney of diabetic rats were markedly ameliorated by FA treatment. Furthermore, FA acid was found to attenuate chronic inflammation induced by both Carrageenan and dextran in rats. We conclude that FA confers protection against injuries in the kidneys of diabetic rats by increasing activities of antioxidant enzymes and inhibiting accumulation of oxidized DNA in the kidney, suggesting a potential drug for the prevention and therapy of DN.

Effects of ferulic acid on diabetic nephropathy in a rat model of type 2 diabetes

Diabetic nephropathy is the most serious complication in diabetes mellitus. It is known that oxidative stress and inflammation play a central role in the development of diabetic nephropathy. In this study, we investigated that ferulic acid (FA) known as anti-oxidative agent could effect on diabetic nephropathy by anti-oxidative and anti-inflammatory mechanism. We examined the effects of FA in obese diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats and non-diabetic control Long-Evans Tokushima Otsuka (LETO) rats. We treated FA to experimental rats from 26 to 45 weeks of age. We evaluated ACR, MDA and MCP-1 in 24 h urine and examined renal histopathology and morphologic change in extracted kidneys from rats. Also, we evaluated the ROS production and MCP-1 levels in cultured podocyte after FA treatment. In the FA-treated OLETF rats, blood glucose was significantly decreased and serum adiponectin levels were increased. Urinary ACR was significantly reduced in FA-treated OLETF rats compared with diabetic OLETF rats. In renal histopathology, FA-treated OLETF rats showed decreased glomerular basement membrane thickness, glomerular volume, and mesangial matrix expansion. FA treatment decreased oxidative stress markers and MCP-1 levels in 24 h urine of rats and supernatants of cultured podocyte. In conclusion, it was suggested that FA have protective and therapeutic effects on diabetic nephropathy by reducing oxidative stress and inflammation.

PPARγ as a therapeutic target in diabetic nephropathy and other renal diseases

PURPOSE OF REVIEW

Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated nuclear transcription factor that regulates many important physiological processes including glucose and lipid metabolism, energy homeostasis, cell proliferation, inflammation, immunity and reproduction. The current review aims to summarize and discuss recent findings evaluating the protective effects of PPARγ against kidney diseases with a focus on diabetic nephropathy. We will also delineate the potential underlying mechanisms.

RECENT FINDINGS

PPARγ plays important roles in renal physiology and pathophysiology. Agonists of PPARγ exert protective effects against various kidney diseases including diabetic nephropathy, ischemic renal injury, IgA nephropathy, chemotherapy-associated kidney damage, polycystic kidney diseases and age-related kidney diseases via both systemic and renal actions.

SUMMARY

PPARγ agonists are effective in delaying and even preventing the progression of many renal diseases, especially diabetic nephropathy. PPARγ may represent a promising target for the treatment of renal diseases.

Probiotic Ferulic Acid Esterase Active Lactobacillus fermentum NCIMB 5221 APA Microcapsules for Oral Delivery: Preparation and in Vitro Characterization

Probiotics possess potential therapeutic and preventative effects for various diseases and metabolic disorders. One important limitation for the oral delivery of probiotics is the harsh conditions of the upper gastrointestinal tract (GIT) which challenge bacterial viability and activity. One proposed method to surpass this obstacle is the use of microencapsulation to improve the delivery of bacterial cells to the lower GIT. The aim of this study is to use alginate-poly-L-lysine-alginate (APA) microcapsules to encapsulate Lactobacillus fermentum NCIMB 5221 and characterize its enzymatic activity and viability through a simulated GIT. This specific strain, in previous research, was characterized for its inherent ferulic acid esterase (FAE) activity which could prove beneficial in the development of a therapeutic for the treatment and prevention of cancers and metabolic disorders. Our findings demonstrate that the APA microcapsule does not slow the mass transfer of substrate into and that of the FA product out of the microcapsule, while also not impairing bacterial cell viability. The use of simulated gastrointestinal conditions led to a significant 2.5 log difference in viability between the free (1.10 × 104 ± 1.00 × 103 cfu/mL) and the microencapsulated (5.50 × 106 ± 1.00 × 105 cfu/mL) L. fermentum NCIMB 5221 following exposure. The work presented here suggests that APA microencapsulation can be used as an effective oral delivery method for L. fermentum NCIMB 5221, a FAE-active probiotic strain.

Cardioprotective effect of sodium ferulate in diabetic rats

Reactive oxygen species (ROS) play important roles in the occurrence and development in diabetic cardiomyopathy (DC). Ferulic acid is one of the ubiquitous compounds in diet. Sodium ferulate (SF) is its sodium salt. SF has potent free radical scavenging activity and can effectively scavenge ROS. The study investigated the effect of SF on cardioprotection in diabetic rats. The diabetic rats induced by streptozotocin (STZ) were treated with SF (110mg/kg) by gavage per day for 12 weeks. Results showed that the levels of nitric oxide (NO) and superoxide dismutase (SOD) activity in plasma and myocardium in SF-treated group were significantly higher than those in diabetic control group. The levels of malondialdehyde (MDA) in plasma and myocardium in SF-treated group were significantly lower than those in diabetic control group. Expression of connective tissue growth factor (CTGF) in myocardium in SF-treated group was apparently lower than that in diabetic control group. Compared with normal control group, electron micrographs of myocardium in diabetic control group showed apparently abnormality, while that was significantly ameliorated in SF-treated group. The study demonstrated that SF has a cardioprotective effect via increasing SOD activity and NO levels in plasma and myocardium, inhibiting oxidative stress in plasma and myocardium, and inhibiting the expression of CTGF in myocardium in diabetes rats.

Thiamine prevents obesity and obesity-associated metabolic disorders in OLETF rats

We previously found that thiamine mitigates metabolic disorders in spontaneously hypertensive rats, harboring defects in glucose and fatty acid metabolism. Mutation of thiamine transporter gene SLC19A2 is linked to type 2 diabetes mellitus. The current study extends our hypothesis that thiamine intervention may impact metabolic abnormalities in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, exhibiting obesity and metabolic disorders similar to human metabolic syndrome. Male OLETF rats (4 wk old) were given free access to water containing either 0.2% or 0% of thiamine for 21 and 51 wk. At the end of treatment, blood parameters and cardiac functions were analyzed. After sacrifice, organs weights, histological findings, and hepatic pyruvate dehydrogenase (PDH) activity in the liver were evaluated. Thiamine intervention averted obesity and prevented metabolic disorders in OLETF rats which accompanied mitigation of reduced lipid oxidation and increased hepatic PDH activity. Histological evaluation revealed that thiamine alleviated adipocyte hypertrophy, steatosis in the liver, heart, and skeletal muscle, sinusoidal fibrosis with formation of basement membranes (called pseudocapillarization) which accompanied significantly reduced expression of laminin β1 and nidogen-1 mRNA, interstitial fibrosis in the heart and kidney, fatty degeneration in the pancreas, thickening of the basement membrane of the vasculature, and glomerulopathy and mononuclear cell infiltration in the kidney. Cardiac and renal functions were preserved in thiamine treatment. Thiamine has a potential to prevent obesity and metabolic disorders in OLETF rats.

Astragaloside IV synergizes with ferulic acid to inhibit renal tubulointerstitial fibrosis in rats with obstructive nephropathy

BACKGROUND AND PURPOSE

The combination of Chinese herbs, Astragali Radix and Angelicae Sinensis Radix, could alleviate renal interstitial fibrosis. Astragaloside IV (AS-IV) and ferulic acid (FA) are the two major active constituents in this combination. In this study, we employed rats with unilateral ureteral obstruction to determine whether AS-IV and FA have the same renoprotective effects and investigated the mechanisms of this action.

EXPERIMENTAL APPROACH

Renal pathological changes were evaluated after treatment with AS-IV, FA or AS-IV + FA (AF) for 10 days. Meanwhile, the expression of transforming growth factor β₁ (TGF-β₁), fibronectin, α-smooth muscle actin (α-SMA), phosphorylation of c-Jun NH₂-terminal kinase (p-JNK) and nitric oxide (NO) production in kidney were determined. The expressions of fibronectin, α-SMA, mitogen-activated protein kinases [JNK, extracellular signal-regulated kinases (ERK), P38] in TGF-β₁-treated NRK-49F cells or interleukin-1-treated HK-2 cells after AS-IV, FA or AF were assessed.

KEY RESULTS

AF alleviated the infiltration of mononuclear cells, tubular atrophy and interstitial fibrosis; reduced the expression of fibronectin, α-SMA, TGF-β₁ and p-JNK; and dramatically increased the production of NO in obstructed kidneys. Neither AS-IV nor FA alone improved renal damage, but both increased NO production. AF inhibited α-SMA and fibronectin expression in NRK-49F or HK-2 cells. Furthermore, AF significantly inhibited IL-1β-induced JNK phosphorylation, without affecting ERK or P38 phosphorylation. Neither AS-IV nor FA alone had any effect on the cells.

CONCLUSIONS AND IMPLICATIONS

AS-IV synergizes with FA to alleviate renal tubulointerstitial fibrosis; this was associated with inhibition of tubular epithelial–mesenchymal transdifferentiation (EMT) and fibroblast activation, as well as an increase in NO production in the kidney.

Satureja khozestanica essential oil ameliorates progression of diabetic nephropathy in uninephrectomized diabetic rats

Diabetic nephropathy is the common cause of leading to end stage of renal disease (ESRD). Satureja khozestanica essential oil (SKEO) was used as an antioxidant and antidiabetic for the inhibition of diabetic nephropathy. Forty male rats were uninephrectomized and divided in four groups randomly; group one as control, group two diabetic untreatment, groups three and four treatment with SKEO by 250 or 500 ppm in drinking water, respectively. Diabetes was induced in the second, third and fourth groups by alloxan injection subcutaneously. After eight weeks treatment, serum malondialdehyde, serum creatinine and serum urea were measured. The kidney paraffin sections were stained by periodic acid Schiff method. Glomerular volume and glomerular number were estimated by stereological rules. Glomerular sclerosis was studied semi-quantitatively. The means were compared by SPSS 13 software and Mann-Whitney test at p<0.05. Satureja khozestanica essential oil (250 or 500 ppm) significantly inhibited the progression of glomerular hypertrophy, glomerular number loss, glomerulosclerosis, lipid peroxidation, serum urea and creatinine compared with the diabetic untreated group. The level of glomerular number, serum malondialdehyde, serum creatinine and urea in the treated groups was significantly maintained at the same level as that of the control group. In conclusion, satureja essential oil significantly can ameliorate glomerular hypertrophy, loss of glomerular number, glomerulosclerosis and attenuated serum urea and serum creatinine in diabetic rats.

Biochemical properties of two cinnamoyl esterases purified from a Lactobacillus johnsonii strain isolated from stool samples of diabetes-resistant rats

Cinnamic acids (i.e., ferulic and caffeic acids) that are esterified to the vegetable cell walls should be enzymatically released to be absorbed in a mammal's intestines. A low dosage of ferulic acid in rodent diets stimulates insulin production and alleviates symptoms caused by diabetes (M. Sri Balasubashini, R. Rukkumani, and V. P. Menon, Acta Diabetol. 40:118-122, 2003). Several lactic acid bacteria are able to display ferulic acid esterase (FAE) activity, suggesting that their probiotic activity could be, in part, mediated by the slow release of ferulic acid. In the present work, we describe the isolation of one strain identified as being Lactobacillus johnsonii that displayed strong FAE activity in stool samples from diabetes-resistant biobreeding rats. These animals are genetically susceptible to becoming diabetic but do not develop the disease. By using genomic analysis coupled to protein purification and catalytic screening, we were able to purify two proteins with FAE activity. The enzymes displayed 42% sequence identity and a broad range of substrate preferences. High affinities and catalytic efficiencies toward aromatic compounds such as ethyl ferulate (K(m) = 20 to 60 microM) and chlorogenic acid (K(m) = 10 to 50 microM) were observed. The strain isolated herein as well as the enzymes studied could be potentially useful for the formulation of probiotics to ameliorate diabetes symptoms.

Role of PPARgamma in renoprotection in Type 2 diabetes: molecular mechanisms and therapeutic potential

DN (diabetic nephropathy) is a chronic disease characterized by proteinuria, glomerular hypertrophy, decreased glomerular filtration and renal fibrosis with loss of renal function. DN is the leading cause of ESRD (end-stage renal disease), accounting for millions of deaths worldwide. TZDs (thiazolidinediones) are synthetic ligands of PPARgamma (peroxisome-proliferator-activated receptor gamma), which is involved in many important physiological processes, including adipose differentiation, lipid and glucose metabolism, energy homoeostasis, cell proliferation, inflammation, reproduction and renoprotection. A large body of research over the past decade has revealed that, in addition to their insulin-sensitizing effects, TZDs play an important role in delaying and preventing the progression of chronic kidney disease in Type 2 diabetes. Although PPARgamma activation by TZDs is in general considered beneficial for the amelioration of diabetic renal complications in Type 2 diabetes, the underlying mechanism(s) remains only partially characterized. In this review, we summarize and discuss recent findings regarding the renoprotective effects of PPARgamma in Type 2 diabetes and the potential underlying mechanisms.