Patrícia Garrido

Effects of Sitagliptin Treatment on Dysmetabolism, Inflammation, and Oxidative Stress in an Animal Model of Type 2 Diabetes (ZDF Rat)

The purpose of this paper is to evaluate the chronic effect of sitagliptin on metabolic profile, inflammation, and redox status in the Zucker Diabetic Fatty (ZDF) rat, an animal model of obese type 2 diabetes. Diabetic and obese ZDF (fa/fa) rats and their controls (ZDF +/+) were treated during 6 weeks with vehicle (control) and sitagliptin (10 mg/kg/bw). Glucose, HbA1c, insulin, Total-c, TGs, IL-1β, TNF-α, CRPhs, and adiponectin were assessed in serum and MDA and TAS in serum, pancreas, and heart. Pancreatic histology was also evaluated. Sitagliptin in diabetic rats promoted a decrease in glucose, HbA1c, Total-c, and TGs accompanied by a partial prevention of insulinopenia, together, with a decrease in CRPhs and IL-1β. Sitagliptin also showed a positive impact on lipid peroxidation and hypertension prevention. In conclusion, chronic sitagliptin treatment corrected the glycaemic dysmetabolism, hypertriglyceridaemia, inflammation, and hypertension, reduced the severity of the histopathological lesions of pancreatic endocrine and exocrine tissues, together with a favourable redox status, which might be a further advantage in the management of diabetes and its proatherogenic comorbidities.

Differential effects of acute (extenuating) and chronic (training) exercise on inflammation and oxidative stress status in an animal model of type 2 diabetes mellitus.

This study compares the effects of a single bout of exercise (acute extenuating) with those promoted by an exercise training program (chronic), focusing on low-grade chronic inflammation profile and on oxidative stress status, using the obese ZDF rats as a model of type 2 diabetes mellitus (T2DM). Animals were sacrificed after 12 weeks of a swimming training program and after a single bout of acute extenuating exercise. Glycaemic, insulinemic, and lipidic profile (triglycerides, total-cholesterol) were evaluated, as well as inflammatory (serum CRPhs, TNF-α, adiponectin) and oxidative (lipidic peroxidation and uric acid) status. When compared to obese diabetic sedentary rats, the animals submitted to acute exercise presented significantly lower values of glycaemia and insulinaemia, with inflammatory profile and oxidative stress significantly aggravated. The trained animals showed amelioration of glycaemic and lipidic dysmetabolism, accompanied by remarkable reduction of inflammatory and oxidative markers. In conclusion, the results presented herein suggessted that exercise pathogenesis-oriented interventions should not exacerbate underlying inflammatory stress associated with T2DM.

Hypertension induced by immunosuppressive drugs: a comparative analysis between sirolimus and cyclosporine

The purpose of this study was to compare the effects of sirolimus (SRL) vs cyclosporine (CsA) concerning the cardiovascular mechanisms hypothetically contributing to hypertension development. Three rat groups were studied: control (vehicle), CsA (5 mg/kg/d), and SRL (1 mg/kg/d). The following parameters were evaluated after 7 weeks of treatment: blood pressured (BP) and heart rate (HR; tail cuff), lipid profile, hematology, plasma and platelet 5-HT and catecholamines (HPLC-ECD), and oxidative equilibrium (serum malondialdehyde [MDA] and total antioxidant status [TAS]). Systolic (SBP) and diastolic blood pressure (DBP) values were higher (P < .001) in both the CsA (146.2 +/- 4.5 and 124.9 +/- 4.5 mm Hg) and SRL (148.9 +/- 4.8 and 126.4 +/- 6.0 mm Hg) groups vs the controls (115.9 +/- 3.3 and 99.1 +/- 2.0 mm Hg). However, HR values were elevated in CsA but not SRL animals. The dyslipidemic pattern of CsA was even more enhanced in the SRL group, with significantly higher low-density lipoprotein cholesterol (LDL-c) and triglyceride (TG) levels vs CsA (P < .05); red blood cells, hematocrit, hemoglobin concentration, mean platelet volume, and platelet distribution width were significantly (P < .05) higher in the SRL vs CsA group. The pro-oxidative profile (increased MDA/TAS) in the CsA group was not reproduced in the SRL cohort. While plasma and platelet 5-HT were elevated in SRL rats, catecholamine content was higher in CsA animals. In conclusion, this study demonstrated that CsA and SRL produce identical hypertensive effects. However, while CsA promotes oxidative stress and sympathetic activation, SRL mainly interferes with lipid profile and hematological parameters. Thus, the hypertensive effects of CsA, a calcineurin inhibitor, and of SRL, an mTOR inhibitor, are associated with impairment of distinct cardiovascular pathways.

Iron-Hepcidin Dysmetabolism, Anemia and Renal Hypoxia, Inflammation and Fibrosis in the Remnant Kidney Rat Model

Anemia is a common complication of chronic kidney disease (CKD) that develops early and its severity increases as renal function declines. It is mainly due to a reduced production of erythropoietin (EPO) by the kidneys; however, there are evidences that iron metabolism disturbances increase as CKD progresses. Our aim was to study the mechanisms underlying the development of anemia of CKD, as well as renal damage, in the remnant kidney rat model of CKD induced by 5/6 nephrectomy. This model of CKD presented a sustained degree of renal dysfunction, with mild and advanced glomerular and tubulointerstitial lesions. Anemia developed 3 weeks after nephrectomy and persisted throughout the protocol. The remnant kidney was still able to produce EPO and the liver showed an increased EPO gene expression. In spite of the increased EPO blood levels, anemia persisted and was linked to low serum iron and transferrin levels, while serum interleukin (IL)-6 and high sensitivity C-reactive protein (hs-CRP) levels showed the absence of systemic inflammation. The increased expression of duodenal ferroportin favours iron absorption; however, serum iron is reduced which might be due to iron leakage through advanced kidney lesions, as showed by tubular iron accumulation. Our data suggest that the persistence of anemia may result from disturbances in iron metabolism and by an altered activity/function of EPO as a result of kidney cell damage and a local inflammatory milieu, as showed by the increased gene expression of different inflammatory proteins in the remnant kidney. In addition, this anemia and the associated kidney hypoxia favour the development of fibrosis, angiogenesis and inflammation that may underlie a resistance to EPO stimuli and reduced iron availability. These findings might contribute to open new windows to identify putative therapeutic targets for this condition, as well as for recombinant human EPO (rHuEPO) resistance, which occurs in a considerable percentage of CKD patients.

Inhibition of bladder tumor growth by chitooligosaccharides in an experimental carcinogenesis model.

Urinary bladder cancer is one of the most common cancers worldwide, with the highest incidence in industrialized countries. Patients with cancer commonly use unconventional and complementary therapy including nutraceuticals. In this study we evaluated the efficacy of chitooligosaccharides (in orange juice) in rat bladder cancer chemoprevention and as therapeutic agent, on a rat model of urinary bladder carcinogenesis induced with N-butyl-N-(4-hydroxybutyl) nitrosamine. Results indicate that chitooligosaccharides may have a preventive effect on bladder cancer development and a curative effect upon established bladder tumors, dependent on the concentration ingested 500 mg/kg b.w., every three days, showed capacity to inhibit and prevent the proliferation of bladder cancer; however, this was associated with secondary effects such as hypercholesterolemia and hypertriglyceridemia. The use of lower doses (50 and 250 mg/kg b.w.) showed only therapeutic effects. It is further suggested that this antitumor effect might be due to its expected anti-inflammatory action, as well as by mechanisms not directly dependent of COX-2 inhibition, such as cellular proliferation control and improvement in antioxidant profile.

Omega-3 Fatty Acids Inhibit Tumor Growth in a Rat Model of Bladder Cancer

Omega-3 (ω-3) fatty acids have been tested on prevention and treatment of several cancer types, but the efficacy on “in vivo” bladder cancer has not been analyzed yet. This study aimed at evaluating the chemopreventive efficacy of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) mixture in an animal model of bladder cancer. Forty-four male Wistar rats were divided into 4 groups during a 20-week protocol: control; carcinogen—N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN); ω-3 (DHA + EPA); and ω-3 + BBN. BBN and ω-3 were given during the initial 8 weeks. At week 20 blood and bladder were collected and checked for the presence of urothelium lesions and tumors, markers of inflammation, proliferation, and redox status. Incidence of bladder carcinoma was, control (0%), ω-3 (0%), BBN (65%), and ω-3 + BBN (62.5%). The ω-3 + BBN group had no infiltrative tumors or carcinoma in situ, and tumor volume was significantly reduced compared to the BBN (0.9 ± 0.1 mm3 versus 112.5 ± 6.4 mm3). Also, it showed a reduced MDA/TAS ratio and BBN-induced serum CRP, TGF-β1, and CD31 were prevented. In conclusion, omega-3 fatty acids inhibit the development of premalignant and malignant lesions in a rat model of bladder cancer, which might be due to anti-inflammatory, antioxidant, anti-proliferative, and anti-angiogenic properties.

Cardiac antiapoptotic and proproliferative effect of recombinant human erythropoietin in a moderate stage of chronic renal failure in the rat

Objective: Recombinant human erythropoietin (rhEPO) therapy under circumstances of moderate chronic renal failure (CRF), with yet lower kidney and heart lesion, may have a protective cardiac effect beyond the correction of anemia, whose mechanism deserves better elucidation, namely by clarifying the impact on gene expression profile of markers of apoptosis, inflammation, proliferation, angiogenesis, and lesion/stress in the heart. Materials and Methods: Four groups of rats were studied over a period of 15 weeks (n=7 each): control—without surgery and without drug treatment; rhEPO—treated with 50 IU/kg/week of rhEPO—beta; CRF—submitted to partial nephrectomy (3/4); CRF + rhEPO—CRF with rhEPO treatment after the 3rd week of surgery. The heart was collected in order to evaluate the gene expression, by real-time qPCR, of markers of apoptotic machinery, inflammation/immunology, proliferation/angiogenesis, and lesion/stress. Results: The main findings obtained were (a) CRF rats have demonstrated overexpression of EPO-R in the heart without changes on EPO expression, together with overexpression of Bax/Bcl2 ratio, PCNA, and IL-2; (b) rhEPO therapy on the heart of the rats with CRF induced by partial 3/4 nephrectomy promoted nonhematopoietic protection, demonstrated by the apoptosis prevention, viewed by the Bax/Bcl2 balance, by the promotion of proliferation, due to PCNA increment, and by the immunomodulatory action, expressed by a trend to prevent the IL-2 increment. Conclusion: In this model of moderate CRF, rhEPO treatment showed important cardiac nonhematopoietic effects, expressed mainly by the antiapoptotic and the proproliferative action, suggesting that early rhEPO therapy in moderate stages of CRF might have further therapeutic benefits.

Anti-inflammatory, anti-proliferative and antioxidant profiles of selective cyclooxygenase-2 inhibition as chemoprevention for rat bladder carcinogenesis.

Purpose: To evaluate the efficacy of a selective cyclooxygenase-2 (COX-2) inhibitor in rat bladder cancer chemoprevention, as well as to assess the relevance of inflammation, proliferation and oxidative stress in tumour growth and in its prevention. Methods: Drug treatments were performed during the first 8 weeks, followed by 12 weeks for tumour expression/prevention, in the following groups: control – vehicle; carcinogen – 0.05% of N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN); celecoxib (CEL) – 10 mg/kg/day and preventive CEL+BBN. The bladders were analysed for number and volume of tumour and nature of urothelium lesions. Serum was assessed for markers of inflammation, proliferation and redox status. Results: The main findings were: a) the incidence of carcinoma was: control: 0% (0/8); BBN: 65% (13/20); CEL: 0% (0/8) and BBN+CEL: 12.5% (1/8); b) the mean tumour volume per rat with tumour and per tumour were significantly lower in the BBN+CEL group (21.2 and 5.3±0.4 mm3) vs BBN (138.5±7.5 and 112.5±6.4 mm3); c) the incidence of pre-neoplasic (hyperplasia and dysplasia) and neoplasic (papillary tumours and carcinoma in situ - CIS) lesions were notoriously reduced in the CEL+BBN treatment; d) CEL significantly reduced serum TGF-β1 and CRP and increase TNF-α and IL-1β (P

Inhibition of bladder tumour growth by sirolimus in an experimental carcinogenesis model

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Recombinant human erythropoietin treatment protects the cardio-renal axis in a model of moderate chronic renal failure

Chronic kidney disease (CKD) patients develop anemia because of the low kidney erythropoietin (EPO) production, thus promoting cardiovascular complications. The degree of renal insufficiency might determine the moment to start recombinant human erythropoietin (rhEPO) therapy, but the molecular basis for these options deserves better elucidation. This study aimed to clarify the cardio-renal effects of earlier rhEPO therapy in rats with moderate chronic renal failure (CRF). Four groups of rats were evaluated for 15 weeks (control; rhEPO − 50 IU/kg/week; CRF − 3/4 nephrectomy; CRF + rhEPO) to assess renal and hematology data, EPO levels, blood pressure, heart rate, peripheral catecholamines contents, serum-transforming growth factor-β1 (TGF-β1), kidney gene expression of EPO, Caspase 9 (Casp9), and vascular endothelial growth factor (Vegf). This model of moderate CRF showed moderate and corrected anemia, hypertension, tachycardia, sympathetic overactivity, and increased serum TGF-β1 content. The remnant kidney showed a proliferative profile, with hypertrophy, downregulated gene expression of EPO, and upregulated gene expression of Vegf and Casp9. rhEPO treatment promoted erythrocytosis and prevented tachycardia and catecholamines increment, with a rise of serum TGF-β1. Furthermore, the decreased kidney gene expression of EPO and the overexpression of Casp9 were prevented, demonstrating a renoprotective action on the remnant kidney. In conclusion, rhEPO therapy promotes a protective effect on the cardio-renal axis, which might be mainly attributed to its pro-proliferative and anti-apoptotic properties. These findings might recommend its use in earlier stages of CRF, acting as an erythropoiesis stimulating agent, to efficiently correct not only the anemia, one of the major complications in these patients, but also the succeeding adverse cardio-renal effects.