Effects of simvastatin on white matter integrity in healthy middle-aged adults

Statins-From Fungi to Pharmacy

Statins have been used in the treatment of hyperlipidemia, both as monotherapy and in combination therapy. Natural fermentation processes of fungi such as Monascus spp., Penicillium spp., Aspergillus terreus, and Pleurotus ostreatus have given rise to natural statins. Compactin (mevastatin), the original naturally occurring statin, is the primary biotransformation substrate in the manufacturing process of marketed drugs. Statins are classified into natural, semi-synthetic derivatives of natural statins, and synthetic ones. Synthetic statins differ from natural statins in their structural composition, with the only common feature being the HMG-CoA-like moiety responsible for suppressing HMG-CoA reductase. Statins do not differ significantly regarding their pleiotropic and adverse effects, but their characteristics depend on their pharmacokinetic parameters and chemical properties. This paper focuses on describing the processes of obtaining natural statins, detailing the pharmacokinetics of available statins, divided into natural and synthetic, and indicating their pleiotropic effects.

Mechanisms of 3-Hydroxyl 3-Methylglutaryl CoA Reductase in Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disease worldwide and has a high incidence in the elderly. Unfortunately, there is no effective therapy for AD owing to its complicated pathogenesis. However, the development of lipid-lowering anti-inflammatory drugs has heralded a new era in the treatment of Alzheimer's disease. Several studies in recent years have shown that lipid metabolic dysregulation and neuroinflammation are associated with the pathogenesis of AD. 3-Hydroxyl 3-methylglutaryl CoA reductase (HMGCR) is a rate-limiting enzyme in cholesterol synthesis that plays a key role in cholesterol metabolism. HMGCR inhibitors, known as statins, have changed from being solely lipid-lowering agents to neuroprotective compounds because of their effects on lipid levels and inflammation. In this review, we first summarize the main regulatory mechanism of HMGCR affecting cholesterol biosynthesis. We also discuss the pathogenesis of AD induced by HMGCR, including disordered lipid metabolism, oxidative stress, inflammation, microglial proliferation, and amyloid-β (Aβ) deposition. Subsequently, we explain the possibility of HMGCR as a potential target for AD treatment. Statins-based AD treatment is an ascent field and currently quite controversial; therefore, we also elaborate on the current application prospects and limitations of statins in AD treatment.

Association of Plasma Lipids with White Matter Hyperintensities in Patients with Acute Ischemic Stroke

Purpose

White matter hyperintensities (WMH) are the common marker of cerebral small vessel disease (CSVD). Dyslipidemia plays a notable role in the pathogenesis of CSVD. However, the relationship between dyslipidemia and WMH is poorly elucidated. This study aims to investigate the association between serum lipid fractions and WMH in patients with acute ischemic stroke (AIS).

Patients and Methods

A total of 901 patients with AIS were included in this study. The burden of WMH, including deep white matter hyperintensities (DWMH), periventricular white matter hyperintensities (PVWMH), and total WMH load, were evaluated on magnetic resonance imaging (MRI) by the Fazekas scale. All the WMH burden were set as dichotomous variables. Serum levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) were collected. The association of serum lipid fractions with WMH burden was analyzed using univariate and multivariate logistic regression models.

Results

The average age of the participants was 67.6±11.6 years, and 584 cases (64.8%) were male. About 33.5% (n = 302) patients were smoker, and 23.5% (n = 212) patients had a history of alcohol consumption. The proportion of previous diabetes, ischemic cardiomyopathy and hypertension was 39.0% (n = 351), 21.2% (n = 191) and 75.9% (n = 684), respectively. The average of serum HDL-c, TC, TG, LDL-c levels for all participants were 1.26 ± 0.28 mmol/l, 4.54 ± 1.06 mmol/l, 1.67 ± 1.09 mmol/l, 3.08 ± 0.94 mmol/l. There were no statistical associations between HDL-c, TG, TC, LDL-c and each type of WMH burden (P > 0.05) in multivariate logistic regression analysis. Similar findings were found in subgroup analysis based on gender classification.

Conclusion

Serum lipid levels were not associated with the presence of any type of WMH in patients with AIS.

Fast dissolving microneedle patch for pronounced systemic delivery of an antihyperlipidemic drug

Fast dissolving microneedles (F-dMN) are quite a novel approach delivering specific drug molecules directly into the bloodstream, bypassing the first-pass effect. The present study reported an F-dMN patch to enhance systemic delivery of simvastatin in a patient-friendly manner. The F-dMN patch was developed using polyvinyl pyrrolidone and polyvinyl alcohol and characterized using light microscopy, SEM, XRD, FTIR, mechanical strength, drug content (%), an ex-vivo penetration study, an ex-vivo drug release study, a skin irritation test, and a pharmacokinetics study. The optimized F-dMN patch exhibited excellent elongation of 35.17%, good tensile strength of 9.68  MPa, an appropriate moisture content of 5.65%, and good penetrability up to 560 µm. Moreover, it showed 93.4% of the drug content within the needles and 81.75% in-vitro release. Histopathological findings and a skin irritation study proved that the F-dMN patch was biocompatible and did not cause any sort of irritation on animal skin. Pharmacokinetic parameters of F-dMN patches were improved (Cmax 6.974 µg/ml, tmax 1 hr and AUC 19. 518 µg.h/ml) as compared to tablet Simva 20 mg solution (Cmax 2.485 µg/ml, tmax 1.4 hr and AUC 11.199 µg.h/ml), thus confirming bioavailability enhancement. Moreover, stability studies confirmed the stability of the developed F-dMN patch, as investigated by axial needle fracture force and drug content.

Does statin use affect amyloid beta deposition and brain metabolism?

BACKGROUND

There are contradictory findings regarding the effect of statin drugs on amyloid β (Aβ) deposition as one of the main hallmarks of Alzheimer's disease (AD), along with tau pathology. We aimed to longitudinally investigate the therapeutic and preventive role of statin drugs by examining the brain Aβ deposition and metabolism rate in AD, mild cognitive impairment (MCI), and healthy controls (HC).

METHODS

The data of 828 subjects including 178 HC, 492 MCI, and 158 AD individuals were obtained from ADNI. The baseline and longitudinal [18 F] AV45 and 18-fluorodeoxyglucose (FDG) PET standard uptake value ratio (SUVR) measures were investigated among statin users and non-users.

RESULTS

Our results showed that there is no significant difference in baseline Aβ deposition and metabolism rate between statin users and non-users among HC, MCI, and AD subjects. While there was no significant effect of statin on metabolism rate, there was a significant difference in Aβ deposition change after 4 years (from baseline) between statin users and non-users within HC subjects (p = 0.011). The change of Aβ deposition at 4 years from baseline was -2.0 ± 6.3% for statin users and 1.4 ± 4.7% for non-users. There was no significant association between statin duration use with baseline and longitudinal Aβ deposition and metabolism rate. However, statin dosage was significantly associated with Aβ deposition in 2 years (r = -0.412, p = 0.021) in the HC group. Moreover, our analysis showed a significant correlation between total statin exposure (duration×dosage) and Aβ deposition in 2 years visit (r = -0.198, p = 0.037) in HC subjects. Furthermore, we investigated the longitudinal changes within each group of statin users and non-users separately in linear mixed models. Our findings showed that there are no significant changes in AV45 and FDG SUVR among both groups.

CONCLUSION

The present longitudinal analysis revealed that using statins might be beneficial in slowing down or stabilizing the Aβ deposition due to aging in subjects without cognitive impairment. However, once the clinical symptoms of cognitive impairment appear, statins fail to slow down Aβ deposition. Overall, our findings revealed that statin users might have slower Aβ aggregation than non-users.

Use of Lipid-Lowering Drugs After Intracerebral Hemorrhage

Hyperlipidemia is common in patients with intracerebral hemorrhage (ICH). Accumulating evidence indicates that patients with ICH are at risk for future hemorrhage recurrence, cardiovascular disease, and ischemic stroke and highlights the importance of secondary prevention of vascular events after ICH. Although the benefits of intensive treatment of hyperlipidemia for reducing ischemic cardiac and vascular events in patients with ischemic stroke are well established, the benefit versus harm in patients with ICH are less clear. Epidemiological studies suggest that hyperlipidemia is protective against ICH and that intensive lowering of lipids is associated with increased risk for ICH. Similarly, although currently available lipid-lowering treatments have been thoroughly studied in patients with ischemic cardiac and vascular disease, only few randomized trials of these therapies included a very small number of patients with history of ICH. Thus, limiting any definitive conclusions regarding the safety and net benefit of these treatments in ICH populations. Currently, there is no consensus regarding the optimal strategy for management of hyperlipidemia after ICH. In this article, we review relevant literature to outline the competing risks and benefits of lipid-lowering treatments in this vulnerable patient population. We suggest a treatment paradigm based on available data but note that data from dedicated randomized trials are needed to build the necessary evidence to guide optimal lipid-lowering strategy in patients with a history of ICH.

Vascular Cognitive Impairment (VCI)

Vascular cognitive impairment (VCI) is predominately caused by vascular risk factors and cerebrovascular disease. VCI includes a broad spectrum of cognitive disorders, from mild cognitive impairment to vascular dementia caused by ischemic or hemorrhagic stroke, and vascular factors alone or in a combination with neurodegeneration including Alzheimer's disease (AD) and AD-related dementia. VCI accounts for at least 20-40% of all dementia diagnosis. Growing evidence indicates that cerebrovascular pathology is the most important contributor to dementia, with additive or synergistic interactions with neurodegenerative pathology. The most common underlying mechanism of VCI is chronic age-related dysregulation of CBF, although other factors such as inflammation and cardiovascular dysfunction play a role. Vascular risk factors are prevalent in VCI and if measured in midlife they predict cognitive impairment and dementia in later life. Particularly, hypertension, high cholesterol, diabetes, and smoking at midlife are each associated with a 20 to 40% increased risk of dementia. Control of these risk factors including multimodality strategies with an inclusion of lifestyle modification is the most promising strategy for treatment and prevention of VCI. In this review, we present recent developments in age-related VCI, its mechanisms, diagnostic criteria, neuroimaging correlates, vascular risk determinants, and current intervention strategies for prevention and treatment of VCI. We have also summarized the most recent and relevant literature in the field of VCI.