Evidence has been accumulated demonstrating that heavy metals may accumulate in various organs leading to tissue damage and toxic effects in mammals. In particular, the Central Nervous System (CNS) seems to be particularly vulnerable to cumulative concentrations of heavy metals, though the pathophysiological mechanisms is still to be clarified. In particular the potential role of oligodendrocyte dysfunction and myelin production after exposure to subtoxic concentration of heavy metals is to be better assessed. Here we investigated on the effect of sub-toxic concentration of several essential (Cu^{2 +}, Cr³⁺, Ni²⁺, Co²⁺) and non-essential (Pb²⁺, Cd²⁺, Al³⁺) heavy metals on MO3.13 and SHSY5Y human oligodendrocyte and neuronal cell lines (grown individually or in co-culture). In particular, exposure of both cell lines to heavy metals produced a reduced cell viability of co-cultured cell lines compared to cells grown separately. This effect was more pronounced in neurons which were more sensitive to metals than oligodendrocytes when the cells were grown in co-culture. On the other hand, a significant reduction of lipid component in cells occurred after their exposure to heavy metals, an effect accompanied by substantial reduction of the main protein that makes up myelin (MBP) in co-cultured cells. Finally, the effect of heavy metals in oligodendrocytes were associated to imbalanced intracellular calcium ion concentration as measured through the fluorescent Rhod-2 probe, thus confirming that heavy metals, even used at subtoxic concentrations, lead to dysfunctional oligodendrocytes. In conclusion, our data show, for the first time, that sub-toxic concentrations of several heavy metals lead to dysfunctional oligodendrocytes, an effect highlighted when these cells are co-cultured with neurons. The pathophysiological mechanism(s) underlying this effect is to be better clarified. However, imbalanced intracellular calcium ion regulation, altered lipid formation and, finally, imbalanced myelin formation seem to play a major role in early stages of heavy metal-related oligodendrocyte dysfunction.

Oligodendrocytes are myelinating cells of the central nervous system, which are generated by progenitor oligodendrocytes as a result of maturation processes. The main function of mature oligodendrocytes is to produce myelin, a lipid-rich multi-lamellar membrane that wraps tightly around neuronal axons, isolating them and facilitating nerve conduction through saltatory propagation. The myelination process requires the consumption of a lot of energy and a high metabolic turnover. Mitochondria are essential organelles which regulate many cellular functions including the energy production through oxidative phosphorylation. Any mitochondrial dysfunction impacts cellular metabolism and negatively affects the health of the organism. If the functioning of the mitochondria is unbalanced the myelination process is impaired. At the end of myelination, oligodendrocytes synthesize about 40% of the total lipids present in the brain. Since lipid synthesis occurs in the cellular endoplasmic reticulum, the alteration of this organelle can lead to partial or deficient myelination, triggering numerous neurodegenerative diseases. In this review the main dysfunctions of oligodendrocytes caused by exogenous or endogenous stimuli will be investigated. Furthermore, the oligodendrocyte reactions to excessive mitochondrial oxidative stress and an altered regulation of the functioning of the endoplasmic reticulum will be discussed.

Abstract: SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection is associated, alongside with lung infection and respiratory disease, to cardiovascular dysfunction that occurs at any stage of the disease. This includes ischemic heart disease, arrhythmias, and cardiomyopathies. The common pathophysiological link between SARS-CoV-2 infection and the cardiovascular events is represented by coagulation abnormalities and disruption of factors released by endothelial cells which contribute in maintaining the blood vessels into an anti-thrombotic state. Thus, early alteration of the functionality of endothelial cells, which may be found soon after SARS-CoV-2 infection, seems to represent the major target of SARS CoV-2 disease state and accounts for the systemic vascular dysfunction that leads to detrimental effect in terms of hospitalization and death accompanying the disease. In particular, the molecular interaction of SARS-CoV-2 with ACE2 receptor located in endothelial cell surface, either at the pulmonary and systemic level, leads to early impairment of endothelial function which, in turn, is followed by vascular inflammation and thrombosis of peripheral blood vessels. This highlights systemic hypoxia and further aggravates the vicious circle that compromises the development of the disease leading to irreversible tissue damage and death of patients with SARS CoV-2 infection. The review aims to assess some recent advances to define the crucial role of endothelial dysfunction in the pathogenesis of vascular complications accompanying SARS-CoV-2 infection. In particular, the molecular mechanisms associated to the interaction of SARS CoV-2 with ACE2 receptor located on the endothelial cells are highlighted to support its role in compromising endothelial cell functionality. Finally, the consequences of endothelial dysfunction in enhancing pro-inflammatory and pro-thrombotic effects of SARS-CoV-2 infection are assessed in order to identify early therapeutic interventions able to reduce the impact of the disease in high-risk patients.

The main neurovascular unit of the Blood Brain Barrier (BBB) consists of a cellular component, which includes endothelial cells, astrocytes, pericytes, microglia, neurons and oligodendrocytes, as well as a non-cellular component resulting from the extracellular matrix. The endothelial cells are the major vital component of the BBB able to preserve the brain homeostasis; these cells are situated along the demarcation line between the bloodstream and the brain. Therefore, an alteration or the progressive disruption of the endothelial layer may clearly impair the brain homeostasis. The proper functioning of the brain endothelial cells is generally ensured by two elements: 1) the presence of junction proteins; 2) the preservation of a specific polarity involving an apical-luminal and a basolateral-abluminal membrane. In view of the above, this review intends to identify the molecular mechanisms underlying BBB function and their changes occurring in early stages of neurodegenerative processes in order to develop novel therapeutic strategies aimed to counteract neurodegenerative disorders.

Abstract Eye health is crucial and the onset of diseases can reduce vision and affect the quality of life of patients. The main causes of progressive and irreversible vision loss include various pathologies such as cataracts, ocular atrophy, corneal opacity, age-related macular degeneration, uncorrected refractive error, posterior capsular opacification, uveitis, glaucoma, diabetic retinopathy, retinal detachment, undetermined disease and other disorders involving oxidative stress and inflammation. The eyes are constantly exposed to the external environment and, for this reason, must be protected from damage from the outside. Many drugs, including cortisonics and antinflammatory drugs have widely been used to counteract eye disorders. However, recent advances have been obtained via supplementation of patients with natural antioxidants and nutraceuticals. In particular, evidence has been accumulated that polyphenols (mostly deriving from Citrus Bergamia) represent a reliable source of antioxidants able to counteract oxidative stress accompanying early stages of eye diseases. Luteolin, in particular, has been found to protect foto-receptors thereby improving vision in many disease states. Moreover, a consistent anti-inflammatory response was found to occur when curcumin is used alone or in combination with other nutraceuticals. On the other hand, CoQ10 has been demonstrated to produce consistent effect in reducing ocular pressure thereby leding to protection in patients undergoing glaucoma. Finally, both grape seed extract rich in anthocyanosides and polynsatured fatty acids (PUFAs) seem to contribute in the prevention of retinal disorders. Thus, combination of nutraceuticals and anti-oxidants may represent the right solution for a multiaction activity in eye protection to be associated to current drug therapies, and this will be of potential interest in early stages of eye disorders.

Rheumatoid arthritis (RA) is a chronic systemic inflammatory autoimmune disease that affects about 1% of the global population, with a female-male ratio of 3:1. To date, genetic predisposition, the involvement of a deficient immune system and lifestyle are known to be the major responsible for the onset of the disease. RA preferably affects the joints, with consequent joint swelling and deformities followed by ankylosis. Patients suffering from rheumatoid arthritis can also develop extra-articular manifestations, which mainly affect the cardiovascular system, the nervous system, the skin, the eye, the respiratory system, the kidney and the gastrointestinal system. It has been shown that about 20% of RA patients can develop neuropathies, multiple mononeuritis, distal sensory neuropathies and sense motor neuropathies. Neurological involvement occurs as a consequence of vasculitis of the nerve vessels leading to vascular ischaemia, axonal degeneration and neuronal demyelination. In RA, the risk of developing cardiovascular disease is very high and depends, most probably, on vascular damage resulting from endothelial dysfunction. Hence, it is reasonable to assume that the integrity of the endothelium is also involved in the neurological disorders resulting from RA. This review aims to highlight the main characteristics of the extra-articular manifestations at the nervous level resulting from rheumatoid arthritis. To this end, the literature main results on these pathological manifestations have been collected with particular focus on the involvement of endothelial dysfunction. In fact, the endothelium could be considered a valuable target for minimizing the incidence of extra-articular neurological manifestations in RA.

Heart failure (HF) is a disease state which has been shown to affect 1-2% of the global population, being often associated with comorbidities such as diabetes, hypertension, obesity or hyperlipidaemia which increase the prevalence of the disease, the rate of hospitalization and the mortality. Although recent advances in both pharmacological and non pharmacological approaches have led to significant improvements in clinical outcomes in patients affected by HF, residual unmet needs remain. Treatment of the disease remains unclear particularly related to poorly defined strategies in the early stages of myocardial dysfunction. Nutritional support in patients developing HF and nutraceutical supplementation have recently been shown to may contribute in the protection of the failing myocardium, though their place in the treatment of HF still needs to be better clarified. In this context, the ONUS-HF working group aimed to assess the optimal nutraceutical approach to HF in the early phases of the disease in order to counteract selected pathways which are imbalanced in the failing myocardium. In particular, we reviewed several of the most relevant pathophysiological and molecular changes occurring druing the early stages of myocardial dysfunction. These include mitochondrial and sarcoplasmic reticulum stress, insufficient nitric oxide (NO) release, cardiac stem cell mobilization and imbalanced regulation of metalloproteinases. Several candidates for nutraceutical supplementation in HF, such as CoQ10, grape seed extract, Olea Europea L- related antioxidants, SGLT2 inhibitors-rich apple extract and bergamot polyphenolic fraction have been assessed for their potential contribution to cardiomyocyte prottection. This approach should define the optimal approach for more targeted and successful strategies based on the use of nutraceuticals in HF to be confirmed by means of clinical trials exploring efficacy and safety of these compounds.

The release of nanomolar concentrations of nitric oxide (NO) by endothelial cells (EC), via activation of constitutive NO synthase (eNOS), represents the pre-requisite for the vaso-protective role of vascular endothelium. On the other hand, exaggerated release of NO as a consequence of activation of inducible NO synthase (iNOS), leads to endothelial dysfunction and, at the late stages, to the development of atherothrombosis. Oxidyzed LDLs (OxyLDL) represent the major candidate to trigger biomolecular processes accompanying endothelial dysfunction and vascular inflammation leading to atherosclerosis development though the pathophysiological mechanism still remains to be elucidated. Here, we summarize recent evidence suggesting that oxyLDL produce significant impairment in the balance in the eNOS/iNOS machinery, downregulating eNOS via HMGB1-TLR4-Caveolin-1 pathway. On the other hand, a sustained activation of the scavenger receptor LOX-1 leads to NFkB activation which, in turn, increases iNOS, leading to EC oxidative stress. Finally, these events are associated to reduced protective autophagic response and accelerated apoptotic EC death which activates atherosclerotic development. Taken togheter, these informations shed new light into the pathophysiological mechanisms of oxy-LDL-related impairment of EC functionality and open new perspective in atherothrombosis prevention.