Perspective of synaptic protection after post-infarction treatment with statins

The pleiotropic effects of statins: a comprehensive exploration of neurovascular unit modulation and blood-brain barrier protection

The blood-brain barrier (BBB) is the most central component of the neurovascular unit (NVU) and is crucial for the maintenance of the internal environment of the central nervous system and the regulation of homeostasis. A multitude of neuroprotective agents have been developed to exert neuroprotective effects and improve the prognosis of patients with ischemic stroke. These agents have been designed to maintain integrity and promote BBB repair. Statins are widely used as pharmacological agents for the treatment and prevention of ischemic stroke, making them a cornerstone in the pharmacological armamentarium for this condition. The primary mechanism of action is the reduction of serum cholesterol through the inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, which results in a decrease in low-density lipoprotein cholesterol (LDL-C) and an increase in cholesterol clearance. Nevertheless, basic and clinical research has indicated that statins may exert additional pleiotropic effects beyond LDL-C reduction. Previous studies on ischemic stroke have demonstrated that statins can enhance neurological function, reduce inflammation, and promote angiogenic and synaptic processes following ischemic stroke. The BBB has been increasingly recognized for its role in the development and progression of ischemic stroke. Statins have also been found to play a potential BBB protective role by affecting members of the NVU. This review aimed to provide a comprehensive theoretical basis for the clinical application of statins by systematically detailing how statins influence the BBB, particularly focusing on the regulation of the function of each member of the NVU.

Rosuvastatin protects PC12 cells from hypoxia/reoxygenation-induced injury by inhibiting endoplasmic reticulum stress-induced apoptosis

The endoplasmic reticulum stress (ERS) response serves an important role in cerebral ischemia-reperfusion injury (CIRI). However, to the best of the our knowledge, the effect of rosuvastatin on the ERS response in CIRI has not yet been studied. In the present study, the effect of rosuvastatin on cell damage in CIRI was investigated; furthermore, the effect of rosuvastatin on the ERS response was explored. Firstly, a hypoxia/reoxygenation (H/R)-induced cell damage model was established in PC12 cells. Cell viability was subsequently detected by a Cell Counting Kit-8 assay. A lactate dehydrogenase kit was used to detect cytotoxicity. TUNEL assay was then used to measure the extent of cell apoptosis, and western blotting was used to analyze the expression levels of the apoptosis-associated proteins Bax, Bcl-2, cleaved caspase-3 and cleaved caspase-9. In addition, western blotting was used to detect the expression levels of ERS-associated proteins, including phosphorylated (p)-protein kinase R-like endoplasmic reticulum kinase (PERK), p-eukaryotic initiation factor 2α and other proteins. Treatment with rosuvastatin led to an increased activity of H/R-induced PC12 cells and a decrease in their cytotoxicity. Rosuvastatin also led to an inhibition in apoptosis and ERS in H/R-induced PC12 cells. After administration of the ERS response activator thapsigargin (TG), TG was found to reverse the protective effect of rosuvastatin on injury of H/R-induced PC12 cells. Taken together, these findings have shown that rosuvastatin is able to protect PC12 cells from H/R-induced injury via inhibiting ERS-induced apoptosis, providing a strong theoretical basis for the use of rosuvastatin in the clinical treatment of CIRI.

The Effects of Statins on Neurotransmission and Their Neuroprotective Role in Neurological and Psychiatric Disorders

Statins are among the most widely used drug classes in the world. Apart from their basic mechanism of action, which is lowering cholesterol levels, many pleiotropic effects have been described so far, such as anti-inflammatory and antiatherosclerotic effects. A growing number of scientific reports have proven that these drugs have a beneficial effect on the functioning of the nervous system. The first reports proving that lipid-lowering therapy can influence the development of neurological and psychiatric diseases appeared in the 1990s. Despite numerous studies about the mechanisms by which statins may affect the functioning of the central nervous system (CNS), there are still no clear data explaining this effect. Most studies have focused on the metabolic effects of this group of drugs, however authors have also described the pleiotropic effects of statins, pointing to their probable impact on the neurotransmitter system and neuroprotective effects. The aim of this paper was to review the literature describing the impacts of statins on dopamine, serotonin, acetylcholine, and glutamate neurotransmission, as well as their neuroprotective role. This paper focuses on the mechanisms by which statins affect neurotransmission, as well as on their impacts on neurological and psychiatric diseases such as Parkinson's disease (PD), Alzheimer's disease (AD), vascular dementia (VD), stroke, and depression. The pleiotropic effects of statin usage could potentially open floodgates for research in these treatment domains, catching the attention of researchers and clinicians across the globe.

CDK5 Targeting as a Therapy for Recovering Neurovascular Unit Integrity in Alzheimer's Disease

The neurovascular unit (NVU) is responsible for synchronizing the energetic demand, vasodynamic changes, and neurochemical and electrical function of the brain through a closed and interdependent interaction of cell components conforming to brain tissue. In this review, we will focus on cyclin-dependent kinase 5 (CDK5) as a molecular pivot, which plays a crucial role in the healthy function of neurons, astrocytes, and the endothelium and is implicated in the cross-talk of cellular adhesion signaling, ion transmission, and cytoskeletal remodeling, thus allowing the individual and interconnected homeostasis of cerebral parenchyma. Then, we discuss how CDK5 overactivation affects the integrity of the NVU in Alzheimer's disease (AD) and cognitive impairment; we emphasize how CDK5 is involved in the excitotoxicity spreading of glutamate and Ca2+ imbalance under acute and chronic injury. Additionally, we present pharmacological and gene therapy strategies for producing partial depletion of CDK5 activity on neurons, astrocytes, or endothelium to recover neuroplasticity and neurotransmission, suggesting that the NVU should be the targeted tissue unit in protective strategies. Finally, we conclude that CDK5 could be effective due to its intervention on astrocytes by its end feet on the endothelium and neurons, acting as an intermediary cell between systemic and central communication in the brain. This review provides integrated guidance regarding the pathogenesis of and potential repair strategies for AD.

Regulation of Small GTPase Prenylation in the Nervous System

Mevalonate pathway inhibitors have been extensively studied for their roles in cholesterol depletion and for inhibiting the prenylation and activation of various proteins. Inhibition of protein prenylation has potential therapeutic uses against neurological disorders, like neural cancers, neurodegeneration, and neurotramatic lesions. Protection against neurodegeneration and promotion of neuronal regeneration is regulated in large part by Ras superfamily small guanosine triphosphatases (GTPases), particularly the Ras, Rho, and Rab subfamilies. These proteins are prenylated to target them to cellular membranes. Prenylation can be specifically inhibited through altering the function of enzymes of the mevalonate pathway necessary for isoprenoid production and attachment to target proteins to elicit a variety of effects on neural cells. However, this approach does not address how prenylation affects a specific protein. This review focuses on the regulation of small GTPase prenylation, the different techniques to inhibit prenylation, and how this inhibition has affected neural cell processes.

Considering risk factors for the effectiveness of translational therapies in brain stroke

Multiple studies on cerebral ischemia have been performed in animal models to propose different strategies of neuroprotection that mitigate either the early or late consequences of the disease. These therapies have been successful in reducing the volume of infarction, the proinflammatory cascade, and the amount of free radicals, as well as reversing markers of neurodegeneration, among other events. However, when those strategies are translated to clinical studies, their effectiveness is not reproduced. This review will focus on highlighting some of the main limitations of the animal models of stroke that lead to unsuccessful translational therapies and the common risk factors in humans that should be carefully considered in the experimental design of future studies to generate a more realistic spatiotemporal physiopathology and improve therapeutic efficacy in cerebral ischemia.

Biocatalyzed Synthesis of Statins: A Sustainable Strategy for the Preparation of Valuable Drugs

Statins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, are the largest selling class of drugs prescribed for the pharmacological treatment of hypercholesterolemia and dyslipidaemia. Statins also possess other therapeutic effects, called pleiotropic, because the blockade of the conversion of HMG-CoA to (R)-mevalonate produces a concomitant inhibition of the biosynthesis of numerous isoprenoid metabolites (e.g., geranylgeranyl pyrophosphate (GGPP) or farnesyl pyrophosphate (FPP)). Thus, the prenylation of several cell signalling proteins (small GTPase family members: Ras, Rac, and Rho) is hampered, so that these molecular switches, controlling multiple pathways and cell functions (maintenance of cell shape, motility, factor secretion, differentiation, and proliferation) are regulated, leading to beneficial effects in cardiovascular health, regulation of the immune system, anti-inflammatory and immunosuppressive properties, prevention and treatment of sepsis, treatment of autoimmune diseases, osteoporosis, kidney and neurological disorders, or even in cancer therapy. Thus, there is a growing interest in developing more sustainable protocols for preparation of statins, and the introduction of biocatalyzed steps into the synthetic pathways is highly advantageous—synthetic routes are conducted under mild reaction conditions, at ambient temperature, and can use water as a reaction medium in many cases. Furthermore, their high selectivity avoids the need for functional group activation and protection/deprotection steps usually required in traditional organic synthesis. Therefore, biocatalysis provides shorter processes, produces less waste, and reduces manufacturing costs and environmental impact. In this review, we will comment on the pleiotropic effects of statins and will illustrate some biotransformations nowadays implemented for statin synthesis.

Molecular Communication of a Dying Neuron in Stroke

When a main artery of the brain occludes, a cellular response involving multiple cell types follows. Cells directly affected by the lack of glucose and oxygen in the neuronal core die by necrosis. In the periphery surrounding the ischemic core (the so-called penumbra) neurons, astrocytes, microglia, oligodendrocytes, pericytes, and endothelial cells react to detrimental factors such as excitotoxicity, oxidative stress, and inflammation in different ways. The fate of the neurons in this area is multifactorial, and communication between all the players is important for survival. This review focuses on the latest research relating to synaptic loss and the release of apoptotic bodies and other extracellular vesicles for cellular communication in stroke. We also point out possible treatment options related to increasing neuronal survival and regeneration in the penumbra.

Angelica sinensis Exerts Angiogenic and Anti-apoptotic Effects Against Cerebral Ischemia–Reperfusion Injury by Activating p38MAPK/HIF-1α/VEGF-A Signaling in Rats

This study evaluated the effects of Angelica sinensis extract [Dang Gui (DG)] administered before 60[Formula: see text]min of middle cerebral artery occlusion followed by 3[Formula: see text]d of reperfusion and investigated the involvement of mitogen-activated protein kinase (MAPK)/hypoxia-inducible factor (HIF)-1[Formula: see text] signaling in the cortical ischemic penumbra. DG was intraperitoneally administered at a dose of 0.25[Formula: see text]g/kg (DG-0.25g), 0.5[Formula: see text]g/kg (DG-0.5g), or 1[Formula: see text]g/kg (DG-1g) 30[Formula: see text]min before the onset of cerebral ischemia. Our study results revealed that DG-0.5g and DG-1g pretreatment effectively attenuated cerebral infarct and improved neurological deficits. DG-0.5g and DG-1g pretreatment significantly downregulated glial fibrillary acidic protein (GFAP), cytochrome c, and cleaved caspase-3 expression and upregulated phospho-p38 MAPK (p-p38 MAPK)/p38 MAPK, phospho-cAMP response element-binding protein (p-CREB)/CREB, cytosolic and mitochondrial phospho-Bad (p-Bad)/Bad ratios, and HIF-1[Formula: see text], vascular endothelial growth factor-A (VEGF-A), phospho-90 kDa ribosomal S6 kinase (p-p90RSK), and von Willebrand factor (vWF) expression in the cortical ischemic penumbra. Pretreatment with SB203580, a p38 MAPK inhibitor, dramatically abrogated the upregulating effects of DG-1g on p-p38 MAPK/p38 MAPK, p-CREB/CREB, and p-Bad/Bad ratios and HIF-1[Formula: see text], VEGF-A, and vWF expression and the downregulating effects of DG-1g on GFAP, cytochrome c, cleaved caspase-3, and cerebral infarction. DG-0.5g and DG-1g pretreatment provided neuroprotective effects against astrocyte-mediated cerebral infarction by activating angiogenic and anti-apoptotic signaling. Moreover, the angiogenic and anti-apoptotic effects of DG pretreatment can be attributed to the activation of p38 MAPK/HIF-1[Formula: see text]/VEGF-A/vWF signaling and p38 MAPK/HIF-1[Formula: see text]/VEGF-A/p-Bad-related regulation of cytochrome c/caspase-3 signaling, respectively, in the cortical ischemic penumbra 3[Formula: see text]d after reperfusion.

Dementia, Preclinical Studies in Neurodegeneration and its Potential for Translational Medicine in South America

Latin-American people with dementia will increase to an astounding 368% in 2050, higher than USA and Europe. In addition, to sporadic dementia type like Alzheimer, and vascular dementia (VaD) progression after Cerebrovascular disease is also found. These incidences are increased in Colombia by specific populations affected with pure Neurodegenerative and VaDs like Autosomical Dominant familial Alzheimer’s disease (AD) and Cerebral Autosomal-Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). In spite of the enormous human effort with and economical effort and investment costs, neither sporadic nor genetic kinds of dementia progression have been prevented or blocked yet. Currently, there exist several animal models that partially solve the understanding of the neurodegenerative etiopathogenesis and its treatment. However, when the potential therapies are translated to humans, those do not work or present a limited action. Main difficulties are the diverse comorbility associated to the cause and/or several affected brain regions, reducing the efficacy of some therapies which are limited to a tissue-specific action or modulating a kind of neurotransmission. Global investigation suggests that a general prevention could be achieved with the improvement in the quality of lifestyle, including healthy diet, physical and mental activity, and avoiding mechanical or chemical pro-inflammatory events in an early stage in the most of non-communicable diseases. In this review article, we present some molecular targets and preclinical studies in animal models to propose strategies that could be useful in a future translation to prevent or block neurodegeneration: one is gene therapy; silencing pathogenic genes in critical brain areas where excitotoxicity arise and spread. Another is to take advantage of the natural source and its wide biodiversity of natural products that are capable of identifying, by the blocking and prevention of neurodegeneration. On the other side, the casuistic of pure dementias in the Latin-American region gives an exceptional opportunity to understand the pathogenesis in these human populations. Further, this is in support of the basic and clinical researchers working on an interaction for a better understanding and medical care of mixed dementias, which have more complex factors than pure ones. However, to promote the translation of any therapeutical alternative is necessary to clarify the normative and the protocols for developing clinical trials with original candidates or work upon strategies proposed from South-American countries.