Combination therapy with losartan and l-carnitine protects against endothelial dysfunction of streptozotocin-induced diabetic rats

Comparative Effects of Crocin and Losartan on RAGE, TGF-β, TNF-α Gene Expression and Histopathological Changes of the Liver Tissue in Rats With Diabetes

BACKGROUND AND OBJECTIVES

AGEs, via RAGE, increase the development of hyperglycemia-induced liver damage, and blocking this axis is associated with a reduction in liver disease progression. The goal of this study was to determine how crocin and losartan influenced RAGE, TNF-α and TGF-β gene expression in diabetic rats, as well as histological changes in liver tissue.

MATERIALS AND METHODS

Diabetes was induced in 40 male Wistar rats using Streptozotocin (50 mg/kg, IP). There were five groups of rats: diabetic and healthy groups, diabetic rats given crocin (50 mg/kg), losartan (25 mg/kg) and both (crocin + Los). Serum glucose, ALT and AST levels were measured 4 weeks later. qPCR was used to examine the TNF-α, TGF-β and RAGE gene expression in liver tissue.

RESULTS

Crocin was found to be effective in lowering FBG in the diabetes group. The serum levels of ALT and AST decreased in all treated groups, but this decrease was significant in the crocin + Los group (p < 0.05). The relative expression of RAGE, TNF-α and TGF-β genes was significantly higher in the diabetes group compared to the healthy group. The expression of these genes decreased in groups treated with crocin and Losartan compared to the diabetes group. The highest reduction in RAGE and TGF-β gene expression was reported in those treated with crocin + Los. Histopathology results showed that the diabetes group had more bile ducts and necrosis than the healthy control group, which had no tissue changes. Hepatocyte degeneration, bile duct proliferation, inflammatory changes and hepatocyte necrosis were mild in the treated groups, but no hepatocyte necrosis was observed in the crocin + Los group.

CONCLUSION

Crocin may be a feasible therapeutic agent for treating diabetes and its symptoms when combined with pharmaceutical medications. Human research is still needed to reach clear conclusions.

AT1 receptors modulate ethanol-induced loss of anticontractile effect of perivascular adipose tissue

Ethanol consumption activates renin-angiotensin-aldosterone system (RAAS), which plays a major role in the pro-contractile and hypertensive effects linked to ethanol. We hypothesized that ethanol consumption induces loss of the anticontractile effect of perivascular adipose tissue (PVAT)through RAAS-mediated mechanisms. We examined the contribution of angiotensin II type 1 receptors (AT1R) to ethanol-induced PVAT dysfunction. With this purpose, male Wistar Hannover rats were treated with ethanol 20 % (in volume ratio) and/or losartan (antagonist of AT1R; 10 mg/kg/day, gavage) for 9 weeks. Losartan prevented the increase in blood pressure and the loss of the anticontractile effect of PVAT induced by ethanol consumption. PVAT dysfunction occurred after 3 and 9 weeks of treatment with ethanol in an endothelium-dependent manner. Blockade of AT1R prevented ethanol-induced reduction of adiponectin levels in PVAT from ethanol-treated rats. Functional assays revealed that ethanol impaired the anticontractile effect of PVAT-derived angiotensin (1-7) and endothelial nitric oxide (NO). In conclusion, AT1R are implicated in ethanol-induced loss of the anticontractile effect of PVAT. In PVAT, AT1R activation decreases the production of adiponectin, a PVAT-derived factor that promotes vasorelaxation in an endothelium-dependent manner. In the endothelium, AT1R favors the production of superoxide (O2•-) leading to a reduction in NO bioavailability. These responses impair the vasodilator action induced by PVAT-derived angiotensin (1-7), which occurs via Mas receptors located in endothelial cells. Ethanol-induced PVAT dysfunction favors vascular hypercontractility, a response that could contribute to the hypertensive state associated with ethanol consumption.

The Synergistic Effects of the Combination of L-Carnitine and Lycopene on the Lycopene Bioavailability and Duodenal Health of Roosters

The objective of this study was to investigate the impact of Lycopene and L-Carnitine, individually or in combination, on various physiological and molecular factors related to intestinal health and absorption ability in Roosters, such as intestinal morphology, serum biochemical parameters, genes involved in Lycopene uptake, nutritional transport genes, and tight junction genes. The findings of the study revealed that the combination of L-Carnitine and Lycopene supplementation had been found to increase the serum concentration levels of TP and ALB. Interestingly, the relative mRNA expression of genes responsible for Lycopene uptakes, such as SR-BI and BCO2, was higher in the LC group compared to other groups. Additionally, the expression of specific nutritional transport genes in the duodenum was significantly affected by both CAR and LC supplementation groups. The tight junction gene OCLN showed a significant increase in expression in the combination group compared to using either Lycopene or L-Carnitine alone. This study concludes that using Lycopene and L-carnitine in combination in poultry feed can potentially improve intestinal morphology and serum biochemical parameters, increase Lycopene bioavailability, improve nutrients uptake, and enhance the integrity of duodenal tight junctions in Roosters.

L-carnitine Attenuates DNA Damage and Oxidative Stress in Diabetic Animals

Background: Diabetes is a metabolic disorder characterized by high plasma glucose levels. In this disease, increased production of reactive oxygen species (ROS) results in DNA damage and multiple complications. L-carnitine (LC) has shown a potent antioxidant activity that may reduce oxidative stress. Objectives: This study aims at assaying the effect of LC on DNA damage in streptozotocin-induced diabetic rats and evaluating the changes in antioxidant markers and liver function enzymes after the administration of LC . Methods: In the present study, for induction of diabetes, we injected a single dose of streptozotocin (65 mg/kg) by the intraperitoneal route, and diabetic rats were treated with LC 200, 300, and 400 mg/kg daily for 3 weeks. We detected the DNA damage at 7, 14, and 21 days after induction diabetes by the comet assay method. The blood glucose level, plasma alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were tested. Also, we measured the activity levels of superoxide dismutase (SOD) and intracellular glutathione (GSH). Results: The results of this study demonstrated the increasing amount of DNA damage with the amount and duration of hyperglycemia. L-carnitine treatment significantly decreased the parameters of genotoxicity such as % DNA in the tail, tail length, and tail moment over time. Moreover, the treatment of diabetic rats with LC 300 and 400 mg/kg/day after 21 days led to a remarkable decrease in blood glucose than diabetic rats. Also, we observed that LC can ameliorate enzyme liver function and reduce oxidative stress via enhancement of GSH and SOD levels. Conclusions: The results of this study indicated the protective effect of LC against DNA damage and oxidative stress in diabetic rats.

Dimethyl fumarate ameliorates diabetes-associated vascular complications through ROS-TXNIP-NLRP3 inflammasome pathway

Vascular complications are a leading cause of morbidity and mortality among diabetic patients. This work aimed to investigate possible influences of dimethyl fumarate (DMF) on streptozotocin (STZ) diabetes-associated vascular complications in rats, exploring its potential to modulate ROS-TXNIP-NLRP3 inflammasome pathway. Two weeks after induction of diabetes (via a single injection of 50 mg/kg STZ, i.p.), diabetic rats were administered either DMF (25 mg/kg/day) or its vehicle for further eight weeks. Age-matched normal and DMF-administered non-diabetic rats served as controls. DMF treatment elicited a mild ameliorative effect on diabetic glycemia. DMF reduced serum TG and AGE levels and enhanced serum HDL-C concentrations in diabetic rats. Moreover, DMF significantly diminished aortic levels of ROS and MDA and restored aortic GSH, SOD and Nrf2 to near-normal levels in STZ rats. Aortic mRNA levels of TXNIP, NLRP3 and NF-κB p65 in diabetic rats were significantly reduced by DMF treatment. Serum and aortic protein levels of TXNIP and aortic contents of IL-1β, iNOS, NLRP3 and TGF-β1 were significantly lower in DMF-diabetic animals than non-treated diabetic rats. Furthermore, protein expression of TNF-α and caspase-3 in diabetic aortas was greatly attenuated by DMF administration. DMF enhanced eNOS mRNA and protein levels and increased bioavailable NO in diabetic aortas. Functionally, DMF attenuated contractile responses of diabetic aortic rings to KCl and phenylephrine and enhanced their relaxant responses to acetylcholine. DMF also mitigated diabetes-induced fibrous tissue proliferation in aortic tunica media. Collectively, these findings demonstrate that DMF offered vasculoprotective influences on diabetic aortas via attenuation of ROS-TXNIP-NLRP3 inflammasome pathway.

Heme oxygenase-1 contributes to the protective effect of resveratrol against endothelial dysfunction in STZ-induced diabetes in rats

Endothelial dysfunction is a common complication of diabetes that mainly stems from increased reactive oxygen species, which makes antioxidants of great benefit. Resveratrol (RSV) is an antioxidant that shows protective effects in a variety of disease models where the ameliorative effect appears to be mediated, in part, via heme oxygenase-1 (HO-1) induction. However, the pathophysiological relevance of HO-1 in the ameliorative response of RSV in endothelial dysfunction is not clearly defined. The present study was conducted to investigate whether HO-1 plays a role in diabetes-induced vascular dysfunction. Streptozotocin-diabetic rats were treated with RSV (10 mg/kg) in presence or absence of an HO-1 blocker, Zinc protoporphyrin (ZnPP) to assess vascular function and indicators of disease status. We found that RSV treatment significantly abrogated diabetes induced vascular dysfunction. This improvement was associated with the ability of RSV to decrease oxidative stress markers alongside a reduction in the aortic TGF-β expression, elevation of NOS3 expression and aortic nitrite concentration as well as HO activity. These ameliorative effects were diminished when ZnPP was administered prior to RSV. Our results clearly demonstrate the protective effects of RSV in diabetes-associated endothelial dysfunction and verified a causal role of HO-1 in this setting.

Beneficial effects of rosiglitazone and losartan combination in diabetic rats

Diabetes with vascular complication needs strict interventions to retard possible serious complications. This research estimated the possible interaction of rosiglitazone (RGN) with losartan (Los) in diabetic rats. Male Sprague-Dawley rats were randomly divided into nondiabetic rats, diabetic rats, and diabetic rats that received RGN, Los, or a combination of RGN and Los. Measurement of serum glucose, vascular adhesion molecule-1, interleukin-6, tumor necrosis factor-α, aortic lipid peroxide (malondialdehyde), glutathione, superoxide dismutase, and total nitrate/nitrite levels was done. Also, the effects of RGN on the relaxation created by acetylcholine and sodium nitroprusside, contraction of isolated aortic rings provoked by phenylephrine and angiotensin II were determined. Results revealed that RGN or Los had a vasodilating effect to variable degrees indicated by enhanced effects on both acetylcholine-induced relaxation and the antagonistic effect on angiotensin II and phenylephrine-stimulated contraction of diabetic aortas with significant amelioration in serum glucose, vascular adhesion molecule-1, interleukin-6, and tumor necrosis factor-α levels and aortic oxidant/antioxidant balance. Treatment of diabetic rats with a combination of RGN and Los produced a more pronounced effect on the measured parameters compared to the diabetic, RGN-, and Los-treated groups. These findings point out the beneficial effects of RGN and Los combination in diabetic rats.

Ameliorative effects of l-carnitine on rats raised on a diet supplemented with lead acetate

Lead intoxication has been a major health hazard in humans. It affects people at all ages. Its toxicity is associated with various organs of the body and affects different metabolic pathways. Based on histological data, l-carnitine reduced the severity of tissue damage produced as a result of exposure of rats to lead acetate. The main objective of this study was to evaluate the underlying mechanism of protection offered by l-carnitine against lead acetate intoxication using male Sprague-Dawley rats. Forty male Sprague-Dawley rats were randomly divided into four groups with ten rats in each. The first group (G1) served as the control group and animals received standard diet only. The second group (G2) received lead acetate in their diet. The third group (G3) was the l-carnitine treated group and received the normal standard diet supplemented with l-carnitine. While the fourth group (G4) had a diet supplemented with both lead acetate and l-carnitine. At the end of each experiment, blood (serum and whole blood) were collected from each animal and analyzed for the following parameters: serum testosterone levels, serum nitric oxide and serum malondialdehyde. This is in addition to looking at the enzymatic activities of two important enzymes (superoxide dismutase and catalase) and on (glutathione reductase) which are indicative of the antioxidant activities in the whole blood. The results indicated that l-carnitine will counteract the undesirable effects of lead intoxication. It exerted its antioxidant potential by reducing the production of ROS and scavenging free radicals by maintaining and protecting the level of the of antioxidant enzymes SOD, CAT and glutathione peroxidase. Conclusion:l-Carnitine may play an important role in reversing the undesirable effects of lead intoxication. Future studies should be conducted to see whether such an effect is applicable in humans exposed to lead poising.

Very low-dose fluvastatin-valsartan combination decreases parameters of inflammation and oxidative stress in patients with type 1 diabetes mellitus

AIMS

Previously we revealed the effectiveness of a new therapeutic approach with a short-term, very-low dose fluvastatin-valsartan combination on the improvement of arterial function in type 1 diabetes mellitus patients (T1DM). In this study we explored whether this approach influences inflammation and oxidative stress and explored any association of these effects with arterial function improvement.

METHODS

This was a supplementary analysis of the two previous double blind randomized studies (included 44 T1DM patients). Treatment group received very-low dose fluvastatin-valsartan, the control group received placebo. Blood samples were collected and inflammation parameters: high-sensitivity CRP (hsCRP), interleukin 6 (IL-6), vascular cell adhesion molecule-1 (VCAM-1) and oxidative stress parameter total antioxidant status (TAS) were measured.

RESULTS

Treatment decreased hsCRP values (by 56.5%, P<0.05) and IL-6 values (by 33.6%, P<0.05) and increased TAS values (by 21.1%; P<0.05) after 30days of treatment. High sensitivity CRP and TAS remained decreased 3months after treatment discontinuation. Importantly, the anti-inflammatory and anti-oxidative action significantly correlated with arterial function improvement.

CONCLUSIONS

The approach consisting of short-term (30days) treatment with a very low-dose fluvastatin-valsartan combination acts anti-inflammatory and anti-oxidative in T1DM patients. These observations along with the improvement of arterial function support the assumption that this approach could have an important clinical benefit in T1DM patients.

Comparison of the effects of levocetirizine and losartan on diabetic nephropathy and vascular dysfunction in streptozotocin-induced diabetic rats

This work was designed to investigate the effects of levocetirizine, a histamine H1 receptor antagonist, on diabetes-induced nephropathy and vascular disorder, in comparison to an angiotensin II receptor antagonist, losartan. Diabetes was induced in male Sprague Dawley rats by a single intraperitoneal injection of streptozotocin (50mg/kg). Diabetic rats were divided into three groups; diabetic, diabetic-levocetirizine (0.5mg/kg/day) and diabetic-losartan (25mg/kg/day). Treatments were started two weeks following diabetes induction and continued for additional eight weeks. At the end of the experiment, urine was collected and serum was separated for biochemical measurements. Tissue homogenates of kidney and aorta were prepared for measuring oxidative stress, nitric oxide (NO), transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α). Moreover, histological analyses were conducted and aortic vascular reactivity was investigated. Levocetirizine improved renal function in diabetic rats (evidenced by mitigation of diabetes-induced changes in kidney to body weight ratio, serum albumin, urinary proteins and creatinine clearance). Moreover, levocetirizine attenuated the elevated renal levels of TNF-α and TGF-β1, ameliorated renal oxidative stress and restored NO bioavailability in diabetic kidney. These effects were comparable to or surpassed those produced by losartan. Moreover, levocetirizine, similar to losartan, reduced the enhanced responsiveness of diabetic aorta to phenylephrine. Histological evaluation of renal and aortic tissues further confirmed the beneficial effects of levocetirizine on diabetic nephropathy and revealed a greater attenuation of diabetes-induced vascular hypertrophy by levocetirizine than by losartan. In conclusion, levocetirizine may offer comparable renoprotective effect to, and possibly superior vasculoprotective effects than, losartan in streptozotocin-diabetic rats.