Does daily fasting shielding kidney on hyperglycemia-related inflammatory cytokine via TNF-α, NLRP3, TGF-ß1 and VCAM-1 mRNA expression.

This study aimed to investigate the effects of blood glucose control and the kidneys' functions, depending on fasting, in the streptozotocin-induced diabetes model in rats via TNF-α, NLRP-3, TGF-ß1 and VCAM-1 mRNA expression in the present study. 32 Wistar albino rats were allocated randomly into four main groups; H (Healthy, n = 6), HF (Healthy fasting, n = 6), D (Diabetes, n = 10), DF (Diabetes and fasting, n = 10). Blood glucose and HbA1c levels significantly increased in the D group compared to the healthy ones (p < 0.05). However, the fasting period significantly improved blood glucose and HbA1c levels 14 days after STZ induced diabetes in rats compared to the D group. Similar findings we obtained for serum (BUN-creatinine) and urine samples (creatinine and urea levels). STZ induced high glucose levels significantly up-regulated TNF-α, NLRP-3, TGF-ß1 and VCAM-1 mRNA expression and fasting significantly decreased these parameters when compared to diabetic rats. Histopathological staining also demonstrated the protective effects of fasting on diabetic kidney tissue. In conclusion, intermittent fasting regulated blood glucose level as well as decreasing harmful effects of diabetes on kidney tissue. The fasting period significantly decreased the hyperglycemia-related inflammatory cytokine damage on kidneys and also reduced apoptosis in favor of living organisms.

Based on urine metabolomics to study the mechanism of Qi-deficiency affecting type 2 diabetes rats using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

Qi-deficiency also called energy deficiency, which approximates to the term of sub-health in contemporary medical theory. Diabetes is similar to the symptoms of "xiaoke" in traditional Chinese medicine (TCM) which is linked with Qi-deficiency. However, the mechanism of Qi-deficiency on type 2 diabetes (T2D) has not been completely elucidated. In this study, a model on Qi-deficiency T2D rat was established by using diet with high fat and high sugar and small-dose STZ induction combined with exhaustive swimming, and the model was evaluated by pathological section, hematological index and serum biochemical parameters. Applying urine metabolomics based on ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry to explore the underlying molecular mechanism of Qi-deficiency on T2D and 32 urinary metabolites were identified as prospective biomarkers for Qi-deficiency T2D rats. Metabolic pathway analysis indicated that synthesis and degradation of ketone bodies, starch and sucrose metabolism, phenylalanine metabolism, arachidonic acid metabolism, butanoate metabolism and TCA cycle, etc., were closely related to potential mechanisms of Qi-deficiency on T2D. The metabolomics results can provide reliable data support for complex TCM syndrome diagnosis.

Time-based investigation of urinary metabolic markers for Type 2 diabetes: Metabolomics approach for diabetes management.

Diabetes is considered one of the most important health emergencies worldwide and Egypt has 8.2 million diabetic patients according to the International Diabetes Federation report in 2017. The objective of this study was to monitor the time-course variation in the metabolic profile of diabetic rats to detect urinary metabolic biomarkers using the metabolomics approach. Type 2 diabetes was induced in male Wistar albino rats using a single intraperitoneal injection of 40 mg/kg of streptozotocin following oral administration of 10% fructose in drinking water for 3 weeks. Then, urine was collected for 24 h from rats at three time points (0, 2, and 4 weeks after confirmation of diabetes), and were analyzed by nuclear magnetic resonance (H1 -NMR), followed by multivariate data analysis. The results from H1 -NMR pointed out that d-glucose, taurine, l-carnitine, l-fucose, 1,5-anhydrosorbitol, and d-galactose levels showed consistent significant variation (p < 0.05) between the positive (diabetic) and negative (normal) controls during the whole experimental period. Also, with the disease progression, myoinositol, and l-phenylalanine levels were significantly altered (p < 0.05) after 2 weeks and this alteration was maintained till the end of the 4-week experimental period in the positive control group. From the results of the present study, it could be concluded that we cannot depend only on glucose levels for prognostic purposes since there are other metabolic disturbances in diabetes which need to be tracked for better disease prognosis.

The effects of high-fat diet and metformin on urinary metabolites in diabetes and prediabetes rat models.

High-fat diet (HFD) interferes with the dietary plan of patients with type 2 diabetes mellitus (T2DM). However, many diabetes patients consume food with higher fat content for a better taste bud experience. In this study, we examined the effect of HFD on rats at the early onset of diabetes and prediabetes by supplementing their feed with palm olein oil to provide a fat content representing 39% of total calorie intake. Urinary profile generated from liquid chromatography-mass spectrometry analysis was used to construct the orthogonal partial least squares discriminant analysis (OPLS-DA) score plots. The data provide insights into the physiological state of an organism. Healthy rats fed with normal chow (NC) and HFD cannot be distinguished by their urinary metabolite profiles, whereas diabetic and prediabetic rats showed a clear separation in OPLS-DA profile between the two diets, indicating a change in their physiological state. Metformin treatment altered the metabolomics profiles of diabetic rats and lowered their blood sugar levels. For prediabetic rats, metformin treatment on both NC- and HFD-fed rats not only reduced their blood sugar levels to normal but also altered the urinary metabolite profile to be more like healthy rats. The use of metformin is therefore beneficial at the prediabetes stage.

Physical Training Is a Potential Modifier of Risk for Contrast-Induced Acute Kidney Injury in Diabetes Mellitus.

BACKGROUND: Iodinated contrast (IC) is a leading cause of hospital-based acute kidney injury (AKI). Contrast-induced acute kidney injury (CI-AKI) is a decline in renal function due to iodinated contrast administration and occurs more frequently in individuals with increasingly common risk factors, such as diabetes mellitus (DM). Physical training (PT) can have renoprotective effects on CI-AKI in diabetic nephropathy. The aim of this study was to evaluate the injury in kidneys of diabetic rats submitted to treatment with IC, evaluating the impact of PT on hemodynamics and renal function in addition to oxidative profile in diabetic rats submitted to IC-AKI. MATERIALS AND METHODS: Adult male Wistar rats are randomized into four groups: citrate (n = 7): control group, citrate buffer (streptozotocin-STZ vehicle), intravenous tail (iv), single dose; DM (n = 7): STZ, 60 mg/kg, iv, single dose; DM+IC (n = 7): DM rats treated with IC (sodium meglumine ioxithalamate, 6 mL/kg, intraperitoneal (ip), single dose); DM+IC+PT (n = 7): DM rats treated with IC as mentioned and submitted to physical training. Renal function parameters (inulin clearance, neutrophil gelatinase-associated lipocalin (NGAL), serum creatinine, and urinary albumin), hemodynamics (renal blood flow and renal vascular resistance), and oxidative profile (urinary peroxides, urinary TBARS, urinary nitric oxide, and renal tissue thiols) were evaluated. RESULTS: It was possible to observe a decrease in inulin clearance, renal blood flow, and thiols in renal tissue accompanied by an increase in urinary flow, serum creatinine, urinary albumin, renal vascular resistance, urinary peroxides, urinary nitrate, and TBARS in the DM group compared to the citrate group. The DM+IC group showed a reduction in inulin clearance, and the renal dysfunction was also seen by the increased NGAL. Renal hemodynamics and oxidative profile compared were also worsened in the DM group. PT improved renal function by increasing renal blood flow and thiol levels in renal tissue and reduced renal vascular resistance, metabolites of reactive oxygen, nitrogen species, and lipid peroxidation in the DM+IC+PT group compared to DM+IC. CONCLUSIONS: Our results confirmed that DM induction increases renal vulnerability to the toxicity of IC and an association between DM with IC predisposes to severe AKI with reduced renal function alongside with renal hemodynamic alterations and oxidative mechanism of injury. The PT showed a renoprotective effect in DM animals subjected to damage with IC by modulating renal hemodynamics and oxidative profile, confirming a potential to modify the risk of CI-AKI when diabetes mellitus is present.

Urinary Metabolomic Profiling in Streptozotocin-Induced Diabetic Mice after Treatment with Losartan.

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease and end-stage kidney disease. Renin-angiotensin system inhibitors such as losartan are the predominant therapeutic options in clinical practice to treat DKD. Therefore, it is necessary to identify DKD-related metabolic profiles that are affected by losartan. To investigate the change in metabolism associated with the development of DKD, we performed global and targeted metabolic profiling using 800 MHz nuclear magnetic resonance spectroscopy of urine samples from streptozotocin-induced diabetic mice (DM) with or without losartan administration. A principal component analysis plot showed that the metabolic pattern in the losartan-treated diabetic mice returned from that in the DM group toward that in the control mice (CM). We found that 33 urinary metabolites were significantly changed in DM compared with CM, and the levels of 16 metabolites among them, namely, glucose, mannose, myo-inositol, pyruvate, fumarate, 2-hydroxyglutarate, isobutyrate, glycine, threonine, dimethylglycine, methyldantoin, isoleucine, leucine, acetylcarnitine, 3-hydroxy-3-methylglutarate, and taurine, shifted closer to the control level in response to losartan treatment. Pathway analysis revealed that these metabolites were associated with branched-chain amino acid degradation; taurine and hypotaurine metabolism; glycine, serine, and threonine metabolism; the tricarboxylic acid cycle; and galactose metabolism. Our results demonstrate that metabolomic analysis is a useful tool for identifying the metabolic pathways related to the development of DKD affected by losartan administration and may contribute to the discovery of new therapeutic agents for DKD.

Pharmacokinetic and metabolomic analyses of Mangiferin calcium salt in rat models of type 2 diabetes and non-alcoholic fatty liver disease.

BACKGROUND: Non-alcoholic fatty liver is one of the most common comorbidities of diabetes. It can cause disturbance of glucose and lipid metabolism in the body, gradually develop into liver fibrosis, and even cause liver cirrhosis. Mangiferin has a variety of pharmacological activities, especially for the improvement of glycolipid metabolism and liver injury. However, its poor oral absorption and low bioavailability limit its further clinical development and application. The modification of mangiferin derivatives is the current research hotspot to solve this problem. METHODS: The plasma pharmacokinetic of mangiferin calcium salt (MCS) and mangiferin were monitored by HPLC. The urine metabolomics of MCS were conducted by UPLC-Q-TOF-MS. RESULTS: The pharmacokinetic parameters of MCS have been varied, and the oral absorption effect of MCS was better than mangiferin. Also MCS had a good therapeutic effect on type 2 diabetes and NAFLD rats by regulating glucose and lipid metabolism. Sixteen potential biomarkers had been identified based on metabolomics which were related to the corresponding pathways including Pantothenate and CoA biosynthesis, fatty acid biosynthesis, citric acid cycle, arginine biosynthesis, tryptophan metabolism, etc. CONCLUSIONS: The present study validated the favorable pharmacokinetic profiles of MCS and the biochemical mechanisms of MCS in treating type 2 diabetes and NAFLD.

Intervention of resistant starch 3 on type 2 diabetes mellitus and its mechanism based on urine metabonomics by liquid chromatography-tandem mass spectrometry.

As a severe metabolic disease, type 2 diabetes mellitus (T2DM) has aroused increasing public attentions. Resistant starch 3 (RS3), as a starch resistant to enzymatic hydrolysis owing to its special structure, has a good effect on improving insulin resistance and reducing blood sugar in T2DM patients. However, the possible mechanisms were barely interpreted yet. In our research, we aimed to evaluate the effects and the possible mechanisms of RS3 on the treatment of T2DM. ICR mice treated with high-fat diet (HFD) for eight weeks, and then injected with streptozotocin (STZ) (100 mg/kg) to establish the T2DM. We choose the mice with the fast blood glucose (FBG) more than 11 mmol/L as T2DM. After treated for 11 weeks the relevant data was analyzed. According to the results, the FBG was dramatically reduced (p < 0.05), which also downregulated triglyceride (p < 0.01) and total cholesterol (p < 0.01). Additionally, the insulin resistance indexes were significantly reduced (p < 0.01), the homeostasis model assessment-ß and insulin-sensitive index were significantly improved (p < 0.01) in RS3 group. Meanwhile, the metabolic profiles of urine were analyzed and 29 potential biomarkers were screened out, including amino acids and lipids. In conclusion, we speculated that the tricarboxylic acid cycle, amino acid metabolism and lipid metabolism played roles in the therapeutic mechanisms of RS3 on T2DM.

The application of metabolomics in investigating anti-diabetic activity of medicinal plants.

Diabetes mellitus is the most prevalent endocrine disease in the world and is likely to be the major epidemic in human history. In current years, many modern anti-diabetic medicines have been produced and introduced into the markets, however, long-term treatment of diabetes using synthetic drugs is limited. Medicinal plants play a great role in the treatment of diabetes. Many medicinal plants and their related traditional treatments for diabetes are used throughout the world and represent promising alternatives for the management of diabetes treatment. Metabolomics researches on diabetes have contributed to many aspects of exploring biomarkers and understanding the progression of the disease at metabolic levels. In addition, in the last decade, a number of metabolomics studies have focused on investigating the action mechanism of various herbal medicines. This paper aims to highlight and review a series of metabolomics studies that carried out on the role of herbal medicines on obesity and diabetes, finding potential biomarkers and also characterizing the metabolic disturbances associated with diabetes development. The findings showed that the metabolism of glycolysis/gluconeogenesis (glucose, pyruvate, lactate), TCA cycle (succinate, citrate, ß-hydroxybutyrate, 2-oxoglutarate), lipid metabolism (acetoacetate, acetate) and amino acid metabolic pathways (valine, leucine, and isoleucine, hippurate, creatine) were more significantly disturbed metabolic pathways and biomarkers in diabetic models and herbal medicines affect these metabolic pathways by different mechanisms.

Urinary Metabolomics and Biochemical Analysis of Antihyperglycemic Effect of Ficus deltoidea Jack Varieties in Streptozotocin-Nicotinamide-Induced Diabetic Rats.

Patients are turning into herbs for the management of diabetes, which cause increasing in the demand of plant-based alternative medicines. Ficus deltoidea or locally known as "Mas Cotek" in Malaysia is a famous herbal plant. However, many varieties of F. deltoidea existed with varied antidiabetic activities inspire us to evaluate in vivo antidiabetic activity of the most available varieties of F. deltoidea. Therefore, antihyperglycemic effect of different varieties of F. deltoidea at dose 250 mg/kg was evaluated on streptozotocin-nicotinamide-induced diabetic rats and further assessed their urinary metabolites using proton nuclear magnetic resonance (1H-NMR). The hyperglycemic blood level improved towards normoglycemic state after 30 days of treatment with standardized extracts of F. deltoidea var. trengganuensis, var. kunstleri, and var. intermedia. The extracts also significantly managed the biochemical parameters in diabetic rats. Metabolomics results showed these varieties were able to manage the altered metabolites of diabetic rats by shifting some of the metabolites back to their normal state. This knowledge might be very important in suggesting the use of these herbs in long-term treatment for diabetes. The most potential variety can be recommended, which may be useful for further pharmacological studies and herbal authentication processes.

Practical Considerations when Using Mouse Models of Diabetes.

Mouse models of diabetes are important tools used in preclinical diabetes research. However, when working with these models, it is important to consider factors that could influence experimental outcome. This is particularly important given the wide variety of models available, each with specific characteristics that could be influenced by extrinsic or intrinsic factors. Blood glucose concentrations, a commonly used and valid endpoint in these models, are particularly susceptible to manipulation by these factors. These include potential effects of intrinsic factors such as strain, sex, and age and extrinsic factors such as husbandry practices and experimental protocols. These variables should therefore be taken into consideration when the model is chosen and the experiments are designed. This chapter outlines common variables that can impact the phenotype of a model, as well as describes the methods used for assessing onset of diabetes and monitoring diabetic mice.

Modulatory Nano/Micro Effects of Diabetes Development on Pharmacology of Primary and Secondary Bile Acids Concentrations.

BACKGROUND: Recent studies have suggested that hyperglycaemia influences the bile acid profile and concentrations of secondary bile acids in the gut. INTRODUCTION: This study aimed to measure changes in the bile acid profile in the gut, tissues, and faeces in type 1 Diabetes (T1D) and Type 2 Diabetes (T2D). METHODS: T1D and T2D were established in a mouse model. Twenty-one seven-weeks old balb/c mice were randomly divided into three equal groups, healthy, T1D and T2D. Blood, tissue, urine and faeces samples were collected for bile acid measurements. RESULTS: Compared with healthy mice, T1D and T2D mice showed lower levels of the primary bile acid, chenodeoxycholic acid, in the plasma, intestine, and brain, and higher levels of the secondary bile acid, lithocholic acid, in the plasma and pancreas. Levels of the bile acid ursodeoxycholic acid were undetected in healthy mice but were found to be elevated in T1D and T2D mice. CONCLUSION: Bile acid profiles in other organs were variably influenced by T1D and T2D development, which suggests similarity in effects of T1D and T2D on the bile acid profile, but these effects were not always consistent among all organs, possibly since feedback mechanisms controlling enterohepatic recirculation and bile acid profiles and biotransformation are different in T1D and T2D.

Enhanced oral bioavailability and anti-diabetic activity of canagliflozin through a spray dried lipid based oral delivery: a novel paradigm.

AIM: Canagliflozin (CFZ), a novel SGLT II antagonist, exhibits erratic absorption after oral administration. The current study entails development and evaluation of spray dried lipid based formulation (solid SMEDDS) for enhancing oral bioavailability and anti-diabetic activity of CFZ. METHODS: Solid SMEDDS developed through spray drying containing Neusilin US2 as an adsorbent. The formed solid SMEDDS were characterized for physicochemical and solid state attributes. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were used to confirm the spherical morphology. In vitro dissolution, ex vivo permeability and in vivo pharmacokinetic studies were conducted to determine the release rate, permeation rate and absorption profile of CFZ, respectively. Pharmacodynamic studies were done as per standard protocols. RESULTS: The optimized solid SMEDDS exhibited acceptable practical yield and flow properties and is vouched with enhanced amorphization, nanoparticulate distribution and acceptable drug content. The spherical morphology of solid SMEDDS and reconstituted SMEDDS were confirmed in SEM and TEM, respectively. In vitro dissolution studies revealed multi-fold release behavior in CFZ in various dissolution media, whereas, remarkable permeability was observed in jejunum segment of rat intestine. Pharmacokinetic studies of CFZ in solid SMEDDS demonstrated 2.53 and 1.43 fold enhancement in Cmax and 2.73 and 1.98 fold in AUC 0-24h, as compared to pure API and marketed formulation, respectively. Pharmacological evaluation of solid SMEDDS revealed enhanced anti-diabetic activity of CFZ through predominant SGLT II inhibition in rats, as evident from evaluation of biochemical levels, urinary glucose excretion studies and SGLT II expression analysis. CONCLUSION: The current work describes significant improvement biopharmaceutical properties of CFZ in solid SMEDD formulation. Graphical abstract Graphical Abstract: Enhanced oral bioavailability and anti-diabetic activity of canagliflozin through a spray dried lipid based oral delivery: a novel paradigm.

Urinary angiotensinogen increases in the absence of overt renal injury in high fat diet-induced type 2 diabetic mice.

AIM OF THE STUDY: During type 2 diabetes (T2D) and hypertension there is stimulation of renal proximal tubule angiotensinogen (AGT), but whether urinary excretion of AGT (uAGT) is an indicator of glomerular damage or intrarenal RAS activation is unclear. We tested the hypothesis that elevations in uAGT can be detected in the absence of albuminuria in a mouse model of T2D. METHODS: Male C57BL/6 mice (N = 10) were fed a high fat (HFD; 45% Kcal from fat) for 28 weeks, and the metabolic phenotype including body weight, blood pressures, glucose, insulin, ippGTT, HOMA-IR, and cholesterol was examined. In addition, kidney Ang II content and reactive oxygen species (ROS) was measured along with urinary albumin, creatinine, Ang II, and AGT. RESULTS: All parameters consistent with T2D were present in mice after 12-14 weeks on the HFD. Systolic BP increased after 18 weeks in HFD but not NFD mice. Intrarenal ROS and Ang II concentrations were also increased in HFD mice. Remarkably, these changes paralleled the augmentation uAGT excretion (3.66 ±â€¯0.50 vs. 0.92 ±â€¯0.13 ng/mg by week 29; P < 0.01), which occurred in the absence of overt albuminuria. CONCLUSIONS: In HFD-induced T2D mice, increases in uAGT occur in the absence of overt renal injury, indicating that this biomarker accurately detects early intrarenal RAS activation.

Macrophage migration inhibitory factor antagonist (p425) ameliorates kidney histopathological and functional changes in diabetic rats / Antagonista (p425) do fator de inibição da migração de macrófagos (MIF) melhora as alterações histopatológicas e funcionais renais em ratos diabéticos

Abstract Introduction: It is hypothesized that increased macrophage migration inhibitory factor (MIF) expression may contribute to diabetic nephropathy (DN) pathogenesis. The aim of the present study was to investigate the renal effects of MIF inhibition in a diabetic experimental model. Methods: Eighteen male Wistar rats (230 ± 20 g) were divided into three groups: 1) control, 2) diabetic (STZ, 50 mg/kg, dissolved in saline, ip), 3) diabetic + MIF antagonist (p425, 1 mg/kg per day, ip, on the 21th day, for 21 consecutive days). The treatment started since we founwd a significant increase in urine albumin excretion (UAE) rate in the diabetic rats in comparison with the control rats. The rats were kept individually in metabolic cages (8 AM-2 PM) and urine samples were collected in the 21 and 42th day. At the end, blood and tissue samples were collected for biochemical (BS, UPE, urine GAG, BUN, Cr, Na, and K) and histological analyses. Results: The results of this study showed that MIF antagonist (p425) significantly decreased urine protein and GAG excretion, urine protein/creatinine ratio, and serum BUN and Cr in the streptozotocin-induced DN in the rats. Pathological changes were significantly alleviated in the MIF antagonist (p425)-administered DN rats. Conclusion: Collectively, these data suggested that MIF antagonist (p425) was able to protect against functional and histopathological injury in the DN.

Resumo Introdução: Supõe-se que elevações da expressão do fator de inibição da migração de macrófagos (MIF) possam contribuir para a patogênese da nefropatia diabética (ND). O objetivo do presente estudo foi investigar os efeitos renais da inibição do MIF em um modelo experimental diabético. Métodos: Dezoito ratos Wistar machos (230 ± 20g) foram divididos em três grupos: 1) controle, 2) diabético (STZ 50 mg/kg dissolvida em soro fisiológico, IP), 3) diabético + antagonista do MIF (p425 1 mg/kg por dia IP no 21o dia por 21 dias consecutivos). O tratamento começou após a identificação de aumento significativo na albuminúria nos ratos diabéticos em relação aos controles. Os ratos foram mantidos individualmente em gaiolas metabólicas (8h-14h) e amostras de urina foram colhidas no 21o e no 42o dia. Ao final do estudo, amostras de sangue e tecido foram colhidas para análises bioquímicas (BS, excreção urinária de proteína, excreção urinária de GAGs, BUN, Cr, Na e K) e histológicas. Resultados: O presente estudo demonstrou que o antagonista do MIF (p425) diminuiu significativamente proteinúria, excreção urinária de GAGs , relação proteína/creatinina na urina, BUN e Cr no grupo com ND induzida por estreptozotocina. As alterações patológicas foram significativamente abrandadas nos ratos com ND que receberam antagonista do MIF (p425). Conclusão: Coletivamente, os dados sugerem que o antagonista do MIF (p425) teve efeito protetor contra lesões funcionais e histopatológicas da ND.

Gut microbiome-derived phenyl sulfate contributes to albuminuria in diabetic kidney disease.

Diabetic kidney disease is a major cause of renal failure that urgently necessitates a breakthrough in disease management. Here we show using untargeted metabolomics that levels of phenyl sulfate, a gut microbiota-derived metabolite, increase with the progression of diabetes in rats overexpressing human uremic toxin transporter SLCO4C1 in the kidney, and are decreased in rats with limited proteinuria. In experimental models of diabetes, phenyl sulfate administration induces albuminuria and podocyte damage. In a diabetic patient cohort, phenyl sulfate levels significantly correlate with basal and predicted 2-year progression of albuminuria in patients with microalbuminuria. Inhibition of tyrosine phenol-lyase, a bacterial enzyme responsible for the synthesis of phenol from dietary tyrosine before it is metabolized into phenyl sulfate in the liver, reduces albuminuria in diabetic mice. Together, our results suggest that phenyl sulfate contributes to albuminuria and could be used as a disease marker and future therapeutic target in diabetic kidney disease.

Macrophage migration inhibitory factor antagonist (p425) ameliorates kidney histopathological and functional changes in diabetic rats.

INTRODUCTION: It is hypothesized that increased macrophage migration inhibitory factor (MIF) expression may contribute to diabetic nephropathy (DN) pathogenesis. The aim of the present study was to investigate the renal effects of MIF inhibition in a diabetic experimental model. METHODS: Eighteen male Wistar rats (230 ± 20 g) were divided into three groups: 1) control, 2) diabetic (STZ, 50 mg/kg, dissolved in saline, ip), 3) diabetic + MIF antagonist (p425, 1 mg/kg per day, ip, on the 21th day, for 21 consecutive days). The treatment started since we founwd a significant increase in urine albumin excretion (UAE) rate in the diabetic rats in comparison with the control rats. The rats were kept individually in metabolic cages (8 AM-2 PM) and urine samples were collected in the 21 and 42th day. At the end, blood and tissue samples were collected for biochemical (BS, UPE, urine GAG, BUN, Cr, Na, and K) and histological analyses. RESULTS: The results of this study showed that MIF antagonist (p425) significantly decreased urine protein and GAG excretion, urine protein/creatinine ratio, and serum BUN and Cr in the streptozotocin-induced DN in the rats. Pathological changes were significantly alleviated in the MIF antagonist (p425)-administered DN rats. CONCLUSION: Collectively, these data suggested that MIF antagonist (p425) was able to protect against functional and histopathological injury in the DN.

Peptiduria: a potential early predictor of diabetic kidney disease.

BACKGROUND: To protect the kidney effectively with medication in type 2 diabetics, it is crucial to identify such at-risk patients early for treatment. We investigated whether peptiduria precedes proteinuria (the earliest urinary marker in our model), and thereby serve as an early predictor of diabetic nephropathy. METHODS: A longitudinal study was performed in a rat model of diabetic nephropathy. Peptides, defined as degradation products of proteins of < 13 kD size, were quantified by a previously validated method using a combination of Lowry and Biorad protein assays. Peptides in urine were also confirmed by chromatographically separating low molecular weight fractions from urine and quantifying albumin fragments in these fractions by enzyme immunoassay. Also, the mechanism of peptiduria was addressed by measuring acid phosphatase, a marker of lysosomal activity, in urine and on kidney sections (histochemically). RESULTS: In rats with diabetic nephropathy, proteinuria occurred after 12 weeks of diabetes, while peptiduria occurred as early as 2 weeks after diabetes. Peptiduria was confirmed by showing that the chromatographically separated low molecular weight fractions of urine containing albumin fragments is in proportion to the level of peptiduria. The time course of peptiduria paralleled the increase in urinary acid phosphatase suggesting that the mechanism of early peptiduria could be due to upregulation of lysosomal enzyme activity in the tubules. CONCLUSIONS: Our results showing that peptiduria precedes proteinuria in diabetic nephropathy provide a compelling rationale to perform a prospective human clinical trial to investigate whether peptiduria can serve as an early predictor of diabetic nephropathy.

First-dose effect of the SGLT2 inhibitor ipragliflozin on cardiovascular activity in spontaneously diabetic Torii fatty rats.

The first dose of a sodium-dependent glucose cotransporter 2 (SGLT2) inhibitor induces osmotic diuresis and can thereby affect cardiovascular activity in hyperglycemic patients. We aimed to determine whether the first dose of the selective SGLT2 inhibitor ipragliflozin affects cardiovascular activity in non-diabetic Sprague-Dawley (SD) rats and Spontaneously Diabetic Torii (SDT) fatty rats in two studies, a urine collection study and a telemetry study. In the former study, urine was collected for 24 hours after a single oral dose of ipragliflozin. In the latter study, systolic blood pressure (SBP) and heart rate (HR) were continuously monitored for 24 hours under conscious and unrestrained conditions from immediately before the administration of ipragliflozin. The telemetry study was conducted in a crossover design at successive 1 week intervals. Cardiovascular autonomic nerve activity was calculated from the SBP and HR. SDT fatty rats exhibited polyuria, glucosuria and hyperglycemia. In addition, the mean and standard deviation of SBP were higher, while the coefficient of variance of HR was lower than the respective parameters in SD rats. Ipragliflozin increased both urine output and urinary glucose excretion, and the increases were more pronounced in SDT fatty rats than in SD rats. In contrast, ipragliflozin had no effect on SBP, the standard deviation of SBP, HR, and the coefficient of variance of HR, or on autonomic nerve activity in either rat strain. These results suggest that the first dose of the SGLT2 inhibitor ipragliflozin has little impact on cardiovascular activity despite causing glucosuria with osmotic diuresis.

Arabinoxylan Attenuates Type 2 Diabetes by Improvement of Carbohydrate, Lipid, and Amino Acid Metabolism.

SCOPE: Type 2 diabetes is a complex metabolic and endocrine disorder worldwide, which causes severe health and economic problems. The aim of this study is to investigate the molecular mechanisms by which arabinoxylan from Plantago asiatica L. attenuates type 2 diabetes from the perspective of urine metabolomics. METHODS AND RESULTS: High-fat diet and streptozotocin-induced type 2 diabetic rats are treated with arabinoxylan, then the urine samples are collected for untargeted metabolomics analysis by UPLC-Triple-TOF/MS. Diabetes causes significant increases in the levels of acetone, glucose, 2-oxoglutarate, and leucine, and significant decreases in the concentrations of creatine, histidine, lysine, l-tryptophan, hippurate, l-cysteine, kynurenine, and arabitol as compared with normal rats (p < 0.01). And these 12 metabolites (with VIP cut-off value > 1) can be used as biomarkers in type 2 diabetes. A total of 21 urinary metabolites are significantly improved by arabinoxylan administration in diabetic rats, and these metabolites are mainly involved in TCA cycle, and metabolism of lipid and ketone body, taurine and hypotaurine, tryptophan, and branched chain amino acids. CONCLUSION: Arabinoxylan administration improves carbohydrate, lipid, and amino acid metabolism in type 2 diabetic rats, which provide important insights into the mechanisms underlying type 2 diabetes as well as the effects of arabinoxylan.