Evolution and involution of atherosclerosis and its relationship with vascular reactivity in hypercholesterolemic rabbits

Bioactivities of Jojoba Oil Beyond Skincare

Jojoba oil, which is extracted from jojoba plant seeds that are native to North America, possesses a unique molecular structure and is distinct from other oils. Unlike typical oils, which mostly contain triglycerides, jojoba oil is composed of long monounsaturated esters, affording it exceptional properties and is valuable across cosmetics, chemicals, and pharmaceuticals. While jojoba oil is prevalent in beauty and skincare today, its seeds and oil have ancient roots in folk medicine, used for treating skin and scalp issues, wounds, sore throats, obesity, and even cancer, while enhancing immunity and fostering hair growth. Modern research underscores jojoba oil's pharmacological versatility, demonstrating antioxidant, antidiabetic, anti-acne, anti-inflammatory, antipyretic, and antibacterial properties. Notably, there has been a surge in its utilization in pharmaceuticals, particularly in topical, transdermal, and parenteral formulations. This review provides a comprehensive overview of jojoba oil, encompassing its chemical composition, extraction techniques, health advantages, and pharmaceutical application developments.

In vivo Evidence of Arterial Dynamic Properties Alteration in Atherosclerotic Rabbit

OBJECTIVES

Atherosclerosis severely damages the arterial wall. The aim of this study was to assess in vivo, for the first time, arterial dynamic properties, reactivity, and stiffness in atherosclerotic (ATH) rabbits.

METHODS

The rabbits were fed with 0.3% cholesterol diet. Femoral artery (FA) or abdominal aorta (AA) diameter was recorded by echotracking, together with blood pressure. Arterial reactivity after local administration of agents and stiffness were measured as diameter or pulsatile diameter changes.

RESULTS

FA dilation induced by acetylcholine was reduced in the function of diet duration (9-65 weeks). With mid-term diet duration (35-45 weeks), the dilation to nitroprusside was greatly reduced; the constriction to norepinephrine was reduced but not that to serotonin, thromboxane agonist, or angiotensin II. After 17- and 28-week diet AA and FA stiffness were increased while distensibility was reduced. Arterial stiffness measured by regional pulse wave velocity was unaltered. We observed that after 28-week diet, FA exhibited a stiffened wall at the plaque level and higher distensibility at the upstream site.

DISCUSSION/CONCLUSION

Arterial reactivity and compliance were greatly modified by atherosclerosis, at various degrees dependent on diet duration. ATH rabbit is therefore a suitable model for in vivo investigations of treatments targeting dynamic properties of arterial wall.

Inosine, an endogenous purine nucleoside, avoids early stages of atherosclerosis development associated to eNOS activation and p38 MAPK/NF-kB inhibition in rats

Atherosclerosis is a multifactorial chronic disease, initiated by an endothelial dysfunction. Adenosine and its analogs can change a variety of inflammatory diseases and has shown important effects at different disease models. Inosine is a stable analogous of adenosine, but its effects in inflammatory diseases, like atherosclerosis, have not yet been studied. The aim of this study was to evaluate the pharmacological properties of inosine, administered sub chronically in a hypercholesterolemic model. Male Wistar rats were divided into four groups: control group (C) and control + inosine (C + INO) received standard chow, hypercholesterolemic diet group (HCD) and HCD + inosine (HCD + INO) were fed a hypercholesterolemic diet. At 31st experimentation day, the treatment with inosine was performed for C + INO and HCD + INO groups once daily in the last 15 days. We observed that the hypercholesterolemic diet promoted an increase in lipid levels and inflammatory cytokines production, while inosine treatment strongly decreased these effects. Additionally, HCD group presented a decrease in maximum relaxation acetylcholine induced and an increase in contractile response phenylephrine induced when compared to the control group, as well as it has presented an enhancement in collagen and ADP-induced platelet aggregation. On the other hand, inosine treatment promoted a decrease in contractile response to phenylephrine, evoked an improvement in endothelium-dependent vasorelaxant response and presented antiplatelet properties. Moreover, inosine activated eNOS and reduced p38 MAPK/NF-κB pathway in aortic tissues. Taken together, the present results indicate inosine as a potential drug for the treatment of cardiovascular disorders such as atherosclerosis.

The effects of high-fat diet on implant osseointegration: an experimental study

Objectives

In this study, we investigated whether a high-fat diet (HFD) affected the bone implant connection (BIC) in peri-implant bone.

Materials and Methods

Four male rabbits were used in this study. Dental implant surgery was introduced into each tibia, and four implants were integrated into each animal. In both the normal diet (ND) group (n=2) and HFD group (n=2), 8 implants were integrated, for a total of 16 integrated implants. The animals continued with their respective diets for 12 weeks post-surgery. Afterward, the rabbits were sacrificed, and the BIC was assessed histomorphometrically.

Results

Histologic and histomorphometric analyses demonstrated that BIC was not impaired in the HFD group compared to the ND group.

Conclusion

Within the limitations of this study, we found that HFD did not decrease the BIC in rabbit tibias.

Pro-atherogenic role of smooth muscle Nox4-based NADPH oxidase

Nox4-based NADPH oxidase is a major reactive oxygen species-generating enzyme in the vasculature, but its role in atherosclerosis remains controversial.

OBJECTIVE

Our goal was to investigate the role of smooth muscle Nox4 in atherosclerosis.

APPROACH AND RESULTS

Atherosclerosis-prone conditions (disturbed blood flow and Western diet) increased Nox4 mRNA level in smooth muscle of arteries. To address whether upregulated smooth muscle Nox4 under atherosclerosis-prone conditions was directly involved in the development of atherosclerosis, mice carrying a human Nox4 P437H dominant negative mutation (Nox4DN), specifically in smooth muscle, were generated on a FVB/N ApoE deficient genetic background to counter the effect of increased smooth muscle Nox4. Nox4DN significantly decreased aortic stiffness and atherosclerotic lesions, with no effect on blood pressure. Gene analysis indicated that soluble epoxide hydrolase 2 (sEH) was significantly downregulated in Nox4DN smooth muscle cells (SMC), at both mRNA and protein levels. Downregulation of sEH by siRNA decreased SMC proliferation and migration, and suppressed inflammation and macrophage adhesion to SMC.

CONCLUSIONS

Downregulation of smooth muscle Nox4 inhibits atherosclerosis by suppressing sEH, which, at least in part, accounts for inhibition of SMC proliferation, migration and inflammation.

High doses of garlic extract significantly attenuated the ratio of serum LDL to HDL level in rat-fed with hypercholesterolemia diet

Background

Hypercholesterolemia is associated with an increased risk of heart disease. In this study, we investigated the antihyperlipidemic effects of garlic (Allium sativum L.) in rat models of hypercholesterolemic.

Methods

Wistar male rats were randomly divided into 4 diet groups with garlic supplementation. Male Wistar rats were fed by standard pellet diet (group I), standard diet supplemented with 4 % garlic (group II), lipogenic diet (containing sunflower oil, cholesterol and ethanol) equivalent to 200 mg raw garlic/kg body weight (raw) (group III) and lipogenic diet equivalent to 400 mg raw garlic/kg body weight (raw) (group IV).

Results

Rats fed 400 g/kg garlic extract(GE), had a significantly lower concentration of serum low-density lipoprotein cholesterol (LDL-C) cholesterol and elevated HDL –C cholesterol at day 28 (P < 0.05).In addition,serum levels of LDL-C was lower in the III and IV group than those in the IV group (P < 0.001 for each). However, cholesterol efflux capacity was positively correlated with HDL cholesterol concentration (P < 0 · 0001). It was also directly correlated with garlic supplementation (P < 0 · 0001).

Conclusion

Together Taken, the results are clearly indicative of the beneficial effects of garlic in reducing lateral side effects of hyperlipidemia. Our data demonstrate that GE has protective effects on HDL in rats with high LDL intake. Therefore, it could be used to remedy hypercholesterolemia with help reduce risk of coronary heart disease

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1834155749171141

Most appropriate animal models to study the efficacy of statins: a systematic review

BACKGROUND

In animal models and clinical trials, statins are reported as effective in reducing cholesterol levels and lowering the risk of cardiovascular diseases. We have aggregated the findings in animal models - mice, rats and rabbits - using the technique of systematic review and meta-analysis to highlight differences in the efficacy of statins.

MATERIALS AND METHODS

We searched Medline and Embase. After examining all eligible articles, we extracted results about total cholesterol and other blood parameters, blood pressure, myocardial infarction and survival. Weighted and standard mean difference random effects meta-analysis was used to measure overall efficacy in prespecified species, strains and subgroups.

RESULTS

We included in systematic review 161 animal studies and we analysed 120 studies, accounting for 2432 animals. Statins lowered the total cholesterol across all species, although with large differences in the effect size: -30% in rabbits, -20% in mice and -10% in rats. The reduction was larger in animals fed on a high-cholesterol diet. Statins reduced infarct volume but did not consistently reduce the blood pressure or effect the overall survival. Few studies considered strains at high risk of cardiovascular diseases or hard outcomes.

CONCLUSIONS

Although statins showed substantial efficacy in animal models, few preclinical data considered conditions mimicking human pathologies for which the drugs are clinically indicated and utilized. The empirical finding that statins are more effective in lowering cholesterol derived from an external source (i.e. diet) conflicts with statin's supposed primary mechanism of action.

Effect of pitavastatin on vascular reactivity in hypercholesterolemic rabbits

Background

Pitavastatin is the newest statin available in Brazil and likely the one with fewer side effects. Thus, pitavastatin was evaluated in hypercholesterolemic rabbits in relation to its action on vascular reactivity.

Objective

To assess the lowest dose of pitavastatin necessary to reduce plasma lipids, cholesterol and tissue lipid peroxidation, as well as endothelial function in hypercholesterolemic rabbits.

Methods

Thirty rabbits divided into six groups (n = 5): G1 - standard chow diet; G2 - hypercholesterolemic diet for 30 days; G3 - hypercholesterolemic diet and after the 16^th day, diet supplemented with pitavastatin (0.1 mg); G4 - hypercholesterolemic diet supplemented with pitavastatin (0.25 mg); G5 - hypercholesterolemic diet supplemented with pitavastatin (0.5 mg); G6 - hypercholesterolemic diet supplemented with pitavastatin (1.0 mg). After 30 days, total cholesterol, HDL, triglycerides, glucose, creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT) were measured and LDL was calculated. In-depth anesthesia was performed with sodium thiopental and aortic segments were removed to study endothelial function, cholesterol and tissue lipid peroxidation. The significance level for statistical tests was 5%.

Results

Total cholesterol and LDL were significantly elevated in relation to G1. HDL was significantly reduced in G4, G5 and G6 when compared to G2. Triglycerides, CK, AST, ALT, cholesterol and tissue lipid peroxidation showed no statistical difference between G2 and G3-G6. Significantly endothelial dysfunction reversion was observed in G5 and G6 when compared to G2.

Conclusion

Pitavastatin starting at a 0.5 mg dose was effective in reverting endothelial dysfunction in hypercholesterolemic rabbits.

Intake of heat-expanded amaranth grain reverses endothelial dysfunction in hypercholesterolemic rabbits

Feeding amaranth grain to hypercholesterolemic rabbits showed the property of recovering the lost endothelial function even without removing the hypercholesterolemia-inducing diet. Results suggest an underlying protective effect.

Domestic animal models for biomedical research

Experimental animals in biomedical research provide insights into disease mechanisms and models for determining the efficacy and safety of new therapies and for discovery of corresponding biomarkers. Although mouse and rat models are most widely used, observations in these species cannot always be faithfully extrapolated to human patients. Thus, a number of domestic species are additionally used in specific disease areas. This review summarizes the most important applications of domestic animal models and emphasizes the new possibilities genetic tailoring of disease models, specifically in pigs, provides.