Effects of atorvastatin and simvastatin on oxidative stress in diet-induced hyperhomocysteinemia in Wistar albino rats: a comparative study

Targeting foamy macrophages by manipulating ABCA1 expression to facilitate lesion healing in the injured spinal cord

Spinal cord injury (SCI) triggers a complex cascade of events, including myelin loss, neuronal damage, neuroinflammation, and the accumulation of damaged cells and debris at the injury site. Infiltrating bone marrow derived macrophages (BMDMϕ) migrate to the epicenter of the SCI lesion, where they engulf cell debris including abundant myelin debris to become pro-inflammatory foamy macrophages (foamy Mϕ), participate neuroinflammation, and facilitate the progression of SCI. This study aimed to elucidate the cellular and molecular mechanisms underlying the functional changes in foamy Mϕ and their potential implications for SCI. Contusion at T10 level of the spinal cord was induced using a New York University (NYU) impactor (5 g rod from a height of 6.25 mm) in male mice. ABCA1, an ATP-binding cassette transporter expressed by Mϕ, plays a crucial role in lipid efflux from foamy cells. We observed that foamy Mϕ lacking ABCA1 exhibited increased lipid accumulation and a higher presence of lipid-accumulated foamy Mϕ as well as elevated pro-inflammatory response in vitro and in injured spinal cord. We also found that both genetic and pharmacological enhancement of ABCA1 expression accelerated lipid efflux from foamy Mϕ, reduced lipid accumulation and inhibited the pro-inflammatory response of foamy Mϕ, and accelerated clearance of cell debris and necrotic cells, which resulted in functional recovery. Our study highlights the importance of understanding the pathologic role of foamy Mϕ in SCI progression and the potential of ABCA1 as a therapeutic target for modulating the inflammatory response, promoting lipid metabolism, and facilitating functional recovery in SCI.

Multiple Risk Factors for Heart Disease: A Challenge to the Ethnopharmacological Use of Croton urucurana Baill

Croton urucurana Baill. is a native Brazilian tree, popularly known as "sangra-d'água" or "sangue-de-dragão," based on the red resinous sap of the trunk. Its use has been transmitted through generations based on popular tradition that attributes analgesic, anti-inflammatory, and cardioprotective properties to the tree. However, its cardioprotective effects have not yet been scientifically investigated. Thus, the present study investigated the pharmacological response to an ethanol-soluble fraction from the leaves of C. urucurana in Wistar rats exposed to smoking and dyslipidemia, two important cardiovascular risk factors. The extract was evaluated by high-performance liquid chromatography. Wistar rats received a 0.5% cholesterol-enriched diet and were exposed to cigarette smoke (9 cigarettes/day for 10 weeks). During the last 5 weeks, the animals were orally treated with vehicle (negative control group), C. urucurana extract (30, 100, and 300 mg/kg), or simvastatin (2.5 mg/kg) + enalapril (15 mg/kg). One group of rats that was not exposed to these risk factors was also evaluated (basal group). Electrocardiograms and systolic, diastolic, and mean blood pressure were measured. Blood was collected to measure total cholesterol, triglycerides, urea, and creatinine. The heart and kidneys were collected and processed for oxidative status and histopathological evaluation. The phytochemical analysis revealed different classes of flavonoids and condensed tannins. The model induced dyslipidemia and cardiac and renal oxidative stress and increased levels of urea and creatinine in the negative control group. Treatment with the C. urucurana extract (300 mg/kg) and simvastatin + enalapril decreased cholesterol and triglyceride levels. In contrast to simvastatin + enalapril treatment, the C. urucurana extract exerted cardiac and renal antioxidant effects. No alterations of electrocardiograms, blood pressure, or histopathology were observed between groups. These findings indicate that C. urucurana exerts lipid-lowering, renal, and cardioprotective effects against oxidative stress in a preclinical model of multiple risk factors for heart disease.

The preventive effect of atorvastatin on liver fibrosis in the bile duct ligation rats via antioxidant activity and down-regulation of Rac1 and NOX1

Objectives

Atorvastatin is a cholesterol-lowering agent capable of inhibiting 3-hydroxy-3-methylglutaryl coenzyme A reductase. Recent studies have demonstrated new facets of atorvastatin, such as antioxidant and anti-fibrotic properties. We investigated the effect of atorvastatin on hepatic injury via the measurement of the antioxidant capacity and protein expression of NOX1, Rac1-GTP, and Rac1 in a rat biliary duct ligation (BDL) model.

Materials and Methods

This study is regarded as experimental interventional research in which a total of 32 adult male Wistar rats (200-250 g) were assigned to 4 groups (eight rats per group) as follows: Control group; Control + At group (15 mg\kg\day atorvastatin); BDL group, and BDL+ At group (15 mg\kg\day atorvastatin). Expression levels of Rac1, NOX1, and Rac1-GTP were determined by western blot analysis. Besides, specific biomarkers of oxidative stress in hepatic tissues of all animals were also analyzed.

Results

Atorvastatin reduced liver injury via a decrease in the expression of NOX1, Rac1-GTP, and Rac1 in the BDL group (P<0.05), while the increased contents of protein thiol groups were observed, and the protein carbonylation was decreased in atorvastatin-treated BDL rats compared to the BDL group (P<0.05). Also, administration of atorvastatin in the BDL group significantly lowered oxidative stress through increasing the activity of catalase and superoxide dismutase in comparison with the BDL group (P<0.05).

Conclusion

It seems that atorvastatin has potential advantages in mitigation of liver fibrosis by a decrease in the expression of NOX1, Rac1-GTP, and Rac1, along with, a reduction in oxidative stress of liver tissues in rats induced by BDL.

Crataegus Aronia protects and reverses vascular inflammation in a high fat diet rat model by an antioxidant mechanism and modulating serum levels of oxidized low-density lipoprotein

CONTEXT

Crataegus aronia (Willd.) Bosc (Rosaceae) (syn. Azarolus L) is traditionally used to treat cardiovascular disorders.

OBJECTIVES

To investigate C. aronia protection against a high-fat diet (HFD)-induced vascular inflammation in rats.

MATERIALS AND METHODS

Wistar Male rats (180-220 g) were divided (n = 10/group) as control fed a standard diet (STD), STD + C. aronia (200 mg/kg, orally), HFD, HFD + C. aronia and HFD post-treated with C. aronia. Simvastatin (20 mg/kg) was co- or post-administered as a positive control drug. HFD was given for 8 weeks, and all other treatments were administered for 4 weeks.

RESULTS

Most significantly, co-administration of C. aronia to HFD-fed rats reduced the thickness of aorta tunica media (90 ± 5 vs. 160 ± 11.3 µm) and adventitia (54.3 ± 3.8 vs. 93.6 ± 9.4 µm). It also lowered protein levels of TNF-α (0.51 ± 0.15 and 0.15 ± 0.16 vs. 0.1 ± 0.09%) and IL-6 (0.52 ± 0.19 vs. 1.0 ± 0.2%) in their aorta or serum (5.9 ± 0.91 vs. 12.98 ± 1.3 ng/mL and 78.1 ± 6.7 vs. 439 ± 78 pg/mL, respectively). It also lowered all serum lipids and increased aorta levels of GSH levels (70.4 ± 4.0 vs. 40.7 µM) and activity of SOD (5.7 ± 0.7 vs. 2.9 ± 0.6 U/mg) and decreased serum levels of ox-LDL-c (566.7 ± 46 vs. 1817 ± 147 ng/mL). Such effects were more profound than all other treatments.

CONCLUSIONS

C. aronia inhibits the HFD-induced vascular inflammation and its use in clinical trials is recommended.

Cerebral Small Vessel Disease (CSVD) - Lessons From the Animal Models

Cerebral small vessel disease (CSVD) refers to a spectrum of clinical and imaging findings resulting from pathological processes of various etiologies affecting cerebral arterioles, perforating arteries, capillaries, and venules. Unlike large vessels, it is a challenge to visualize small vessels in vivo, hence the difficulty to directly monitor the natural progression of the disease. CSVD might progress for many years during the early stage of the disease as it remains asymptomatic. Prevalent among elderly individuals, CSVD has been alarmingly reported as an important precursor of full-blown stroke and vascular dementia. Growing evidence has also shown a significant association between CSVD's radiological manifestation with dementia and Alzheimer's disease (AD) pathology. Although it remains contentious as to whether CSVD is a cause or sequelae of AD, it is not far-fetched to posit that effective therapeutic measures of CSVD would mitigate the overall burden of dementia. Nevertheless, the unifying theory on the pathomechanism of the disease remains elusive, hence the lack of effective therapeutic approaches. Thus, this chapter consolidates the contemporary insights from numerous experimental animal models of CSVD, to date: from the available experimental animal models of CSVD and its translational research value; the pathomechanical aspects of the disease; relevant aspects on systems biology; opportunities for early disease biomarkers; and finally, converging approaches for future therapeutic directions of CSVD.

Efficiency of atorvastatin and simvastatin in improving cardiac function during the different degrees of hyperhomocysteinemia

The aim of this study was to assess the impact of atorvastatin and simvastatin on myocardial contractility during the different degrees of hyperhomocysteinemia (HHcy) in rats. Study was conducted on adult male Wistar albino rats (n = 90; 4 weeks old; 100 ± 15 g body mass) in which HHcy was achieved by dietary manipulation. Animals were exposed to pharmacology treatment with atorvastatin in dose of 3 mg/kg per day i.p. or simvastatin in dose of 5 mg/kg per day i.p. at the same time every day, according to equivalent therapeutic doses of these statins (10 mg atorvastatin = 20 mg simvastatin). After the dietary manipulation and pharmacological treatment and confirmation of HHcy, all animals were sacrificed, hearts were isolated, and cardiac function was tested according to the Langendorff technique. Size of recovery of maximum rate of left ventricular development (dp/dtmax), minimum rate of left ventricular development (dp/dtmin), systolic left ventricular development, diastolic left ventricular development, heart rate, and coronary flow at the 40, 60, 80, 100, and 120 cmH2O coronary perfusion pressure were measured in state of physiological condition (homocysteine less than 15 μmol/L), mild HHcy, and moderate HHcy. Atorvastatin treatment significantly attenuated homocysteine-induced impairment of myocyte contractility and dominantly decreased dp/dtmax, dp/dtmin, and heart rate and induced greater changes in systolic left ventricular development compared with simvastatin. Treatment with atorvastatin seems able to revert systolic abnormalities and improve contractility during the different degrees of HHcy.

Nuclear factor erythroid 2-related factor 2 activation mediates hyperhomocysteinemia-associated lipolysis suppression in adipocytes

Hyperhomocysteinemia (HHcy) is associated with suppressed lipolytic response in adipocytes/adipose tissue, however, the underlying mechanism remains to be extensively studied. Nuclear factor erythroid 2-related factor 2 (Nrf2), a master transcriptional factor regulating antioxidant generation, has been recently reported to mediate lipid metabolism. Employing both fully differentiated 3T3-L1 adipocytes and male C57BL/6 mice, in the present study, we investigated the potential involvement of Nrf2 activation in HHcy-mediated lipolytic suppression. Our results showed that homocysteine (Hcy) treatment resulted in suppressed lipolysis, evidenced by increased intracellular triglyceride (TG) accumulation, decreased glycerol and free fatty acid (FFA) in fully differentiated 3T3-L1 adipocytes. Interestingly, Hcy exposure was associated with Nrf2 activation in adipocytes. Further studies showed that Nrf2 knockdown via siRNA transfection ameliorated Hcy-induced glycerol release in adipocytes. On the contrary, Nrf2 activators, epigallocatechin gallate (EGCG) and tert-butylhydroquinone (t-BHQ), increased intracellular TG content and decreased glycerol release in adipocytes. Importantly, our in vitro observations were corroborated by our in vivo findings, in which Hcy feeding (0.1% wt/vol) for four weeks induced Nrf2 expression in adipose tissue and lowered circulating FFA and glycerol levels in mice. Furthermore, EGCG injection (5 mg/kg/d) decreased circulating glycerol levels in comparison to the control group in mice. In conclusion, these results indicated that Nrf2 activation in response to HHcy plays an important role in mediating Hcy-suppressed lipolysis in adipocytes.