Nucleic Acids-Based Biomarkers for Alzheimer's Disease Diagnosis and Novel Molecules to Treat the Disease.

Alzheimer's disease (AD) represents the most common form of dementia and affects million people worldwide, with a high social burden and considerable economic costs. AD diagnosis benefits from a well-established panel of laboratory tests that allow ruling-in patients, along with FDG and amyloid PET imaging tools. The main laboratory tests used to identify AD patients are Aß40, Aß42, the Aß42/Aß40 ratio, phosphorylated Tau 181 (pTau181) and total Tau (tTau). Although they are measured preferentially in the cerebrospinal fluid (CSF), some evidence about the possibility for blood-based determination to enter clinical practice is growing up. Unfortunately, CSF biomarkers for AD and, even more, the blood-based ones, present a few flaws, and twenty years of research in this field did not overcome these pitfalls. The tale even worsens when the issue of treating AD is addressed due to the lack of effective strategies despite the many decades of attempts by pharmaceutic industries and scientists. Amyloid-based drugs failed to stop the disease, and no neuroinflammation-based drugs have been demonstrated to work so far. Hence, only symptomatic therapy is available, with no disease-modifying treatment on hand. Such a desolate situation fully justifies the active search for novel biomarkers to be used as reliable tests for AD diagnosis and molecular targets for treating patients. Recently, a novel group of molecules has been identified to be used for AD diagnosis and follow-up, the nuclei acid-based biomarkers. Nucleic acid-based biomarkers are a composite group of extracellular molecules consisting of DNA and RNA alone or in combination with other molecules, including proteins. This review article reports the main findings from the studies carried out on these biomarkers during AD, and highlights their advantages and limitations.

Effects of Cerebrospinal Fluids from Alzheimer and Non-Alzheimer Patients on Neurons-Astrocytes-Microglia Co-Culture.

Alzheimer's disease (AD) is the most common form of dementia, characterized by the accumulation of ß-amyloid plaques, tau tangles, neuroinflammation, and synaptic/neuronal loss, the latter being the strongest correlating factor with memory and cognitive impairment. Through an in vitro study on a neurons-astrocytes-microglia (NAM) co-culture system, we analyzed the effects of cerebrospinal fluid (CSF) samples from AD and non-AD patients (other neurodegenerative pathologies). Treatment with CSF from AD patients showed a loss of neurofilaments and spheroids, suggesting the presence of elements including CX3CL1 (soluble form), destabilizing the neurofilaments, cellular adhesion processes, and intercellular contacts. The NAM co-cultures were analyzed in immunofluorescence assays for several markers related to AD, such as through zymography, where the expression of proteolytic enzymes was quantified both in cell extracts and the co-cultures' conditioned medium (CM). Through qRT-PCR assays, several genes involved in the formation of ß-amyloid plaque, in phosphorylation of tau, and in inflammation pathways and MMP expression were investigated.

The Cytokine CX3CL1 and ADAMs/MMPs in Concerted Cross-Talk Influencing Neurodegenerative Diseases.

Neuroinflammation plays a fundamental role in the development and progression of neurodegenerative diseases. It could therefore be said that neuroinflammation in neurodegenerative pathologies is not a consequence but a cause of them and could represent a therapeutic target of neuronal degeneration. CX3CL1 and several proteases (ADAMs/MMPs) are strongly involved in the inflammatory pathways of these neurodegenerative pathologies with multiple effects. On the one hand, ADAMs have neuroprotective and anti-apoptotic effects; on the other hand, they target cytokines and chemokines, thus causing inflammatory processes and, consequently, neurodegeneration. CX3CL1 itself is a cytokine substrate for the ADAM, ADAM17, which cleaves and releases it in a soluble isoform (sCX3CL1). CX3CL1, as an adhesion molecule, on the one hand, plays an inhibiting role in the pro-inflammatory response in the central nervous system (CNS) and shows neuroprotective effects by binding its membrane receptor (CX3CR1) present into microglia cells and maintaining them in a quiescent state; on the other hand, the sCX3CL1 isoform seems to promote neurodegeneration. In this review, the dual roles of CX3CL1 and ADAMs/MMPs in different neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (MH), and multiple sclerosis (MS), are investigated.

Cerebrospinal and Blood Biomarkers in Alzheimer's Disease: Did Mild Cognitive Impairment Definition Affect Their Clinical Usefulness?

Despite Alzheimer's Disease (AD) being known from the times of Alois Alzheimer, who lived more than one century ago, many aspects of the disease are still obscure, including the pathogenesis, the clinical spectrum definition, and the therapeutic approach. Well-established biomarkers for AD come from the histopathological hallmarks of the disease, which are Aß and phosphorylated Tau protein aggregates. Consistently, cerebrospinal fluid (CSF) Amyloid ß (Aß) and phosphorylated Tau level measurements are currently used to detect AD presence. However, two central biases affect these biomarkers. Firstly, incomplete knowledge of the pathogenesis of diseases legitimates the search for novel molecules that, reasonably, could be expressed by neurons and microglia and could be detected in blood simpler and earlier than the classical markers and in a higher amount. Further, studies have been performed to evaluate whether CSF biomarkers can predict AD onset in Mild Cognitive Impairment (MCI) patients. However, the MCI definition has changed over time. Hence, the studies on MCI patients seem to be biased at the beginning due to the imprecise enrollment and heterogeneous composition of the miscellaneous MCI subgroup. Plasma biomarkers and novel candidate molecules, such as microglia biomarkers, have been tentatively investigated and could represent valuable targets for diagnosing and monitoring AD. Also, novel AD markers are urgently needed to identify molecular targets for treatment strategies. This review article summarizes the main CSF and blood AD biomarkers, underpins their advantages and flaws, and mentions novel molecules that can be used as potential biomarkers for AD.

CX3CL1 Pathway as a Molecular Target for Treatment Strategies in Alzheimer's Disease.

Alzheimer's disease (AD) is a scourge for patients, caregivers and healthcare professionals due to the progressive character of the disease and the lack of effective treatments. AD is considered a proteinopathy, which means that aetiological and clinical features of AD have been linked to the deposition of amyloid ß (Aß) and hyperphosphorylated tau protein aggregates throughout the brain, with Aß and hyperphosphorylated tau representing classical AD hallmarks. However, some other putative mechanisms underlying the pathogenesis of the disease have been proposed, including inflammation in the brain, microglia activation, impaired hippocampus neurogenesis and alterations in the production and release of neurotrophic factors. Among all, microglia activation and chronic inflammation in the brain gained some attention, with researchers worldwide wondering whether it is possible to prevent and stop, respectively, the onset and progression of the disease by modulating microglia phenotypes. The following key points have been established so far: (i) Aß deposition in brain parenchyma represents repeated stimulus determining chronic activation of microglia; (ii) chronic activation and priming of microglia make these cells lose neuroprotective functions and favour damage and loss of neurons; (iii) quiescent status of microglia at baseline prevents chronic activation and priming, meaning that the more microglia are quiescent, the less they become neurotoxic. Many molecules are known to modulate the quiescent baseline state of microglia, attracting huge interest among scientists as to whether these molecules could be used as valuable targets in AD treatment. The downside of the coin came early with the observation that quiescent microglia do not display phagocytic ability, being unable to clear Aß deposits since phagocytosis is crucial for Aß clearance efficacy. A possible solution for this issue could be found in the modulation of microglia status at baseline, which could help maintain both neuroprotective features and phagocytic ability at the same time. Among the molecules known to influence the baseline status of microglia, C-X3-chemokine Ligand 1 (CX3CL1), also known as Fractalkine (FKN), is one of the most investigated. FKN and its microglial receptor CX3CR1 are crucial players in the interplay between neurons and microglia, modulating the operation of some neural circuits and the efficacy and persistence of immune response against injury. In addition, CX3CL1 regulates synaptic pruning and plasticity in the developmental age and in adulthood, when it strongly impacts the hippocampus neurogenesis of the adult. CX3CL1 has an effect on Aß clearance and tau phosphorylation, as well as in microglia activation and priming. For all the above, CX3CL1/CX3CR1 signalling has been widely studied in relation to AD pathogenesis, and its biochemical pathway could hide molecular targets for novel treatment strategies in AD. This review summarizes the possible role of CX3CL1 in AD pathogenesis and its use as a potential target for AD treatment.

Microglial Activation and Priming in Alzheimer's Disease: State of the Art and Future Perspectives.

Alzheimer's Disease (AD) is the most common cause of dementia, having a remarkable social and healthcare burden worldwide. Amyloid ß (Aß) and protein Tau aggregates are disease hallmarks and key players in AD pathogenesis. However, it has been hypothesized that microglia can contribute to AD pathophysiology, as well. Microglia are CNS-resident immune cells belonging to the myeloid lineage of the innate arm of immunity. Under physiological conditions, microglia are in constant motion in order to carry on their housekeeping function, and they maintain an anti-inflammatory, quiescent state, with low expression of cytokines and no phagocytic activity. Upon various stimuli (debris, ATP, misfolded proteins, aggregates and pathogens), microglia acquire a phagocytic function and overexpress cytokine gene modules. This process is generally regarded as microglia activation and implies that the production of pro-inflammatory cytokines is counterbalanced by the synthesis and the release of anti-inflammatory molecules. This mechanism avoids excessive inflammatory response and inappropriate microglial activation, which causes tissue damage and brain homeostasis impairment. Once the pathogenic stimulus has been cleared, activated microglia return to the naïve, anti-inflammatory state. Upon repeated stimuli (as in the case of Aß deposition in the early stage of AD), activated microglia shift toward a less protective, neurotoxic phenotype, known as "primed" microglia. The main characteristic of primed microglia is their lower capability to turn back toward the naïve, anti-inflammatory state, which makes these cells prone to chronic activation and favours chronic inflammation in the brain. Primed microglia have impaired defence capacity against injury and detrimental effects on the brain microenvironment. Additionally, priming has been associated with AD onset and progression and can represent a promising target for AD treatment strategies. Many factors (genetics, environmental factors, baseline inflammatory status of microglia, ageing) generate an aberrantly activated phenotype that undergoes priming easier and earlier than normally activated microglia do. Novel, promising targets for therapeutic strategies for AD have been sought in the field of microglia activation and, importantly, among those factors influencing the baseline status of these cells. The CX3CL1 pathway could be a valuable target treatment approach in AD, although preliminary findings from the studies in this field are controversial. The current review aims to summarize state of the art on the role of microglia dysfunction in AD pathogenesis and proposes biochemical pathways with possible targets for AD treatment.

Monocyte distribution width (MDW) as a screening tool for early detecting sepsis: a systematic review and meta-analysis.

OBJECTIVES: Monocyte distribution has recently emerged as a promising biomarker of sepsis, especially in acute setting, such as Emergency Department and Intensive Care Unit. This study aimed to evaluate the accuracy of monocyte distribution width (MDW) for early detecting patients with sepsis by performing a systemic review and meta-analysis of published studies. METHODS: Relevant publications were identified by a systematic literature search on PubMed and Google Scholar from inception to September 07, 2021. Studies were divided into two groups based on the sepsis criteria applied, namely sepsis-2 or sepsis-3. RESULTS: Ten studies including 9,475 individuals, of whom 1,370 with sepsis (742 according Sepsis-2 and 628 according to Sepsis-3), met the inclusion criteria for our meta-analysis. The pooled sensitivity and specificity were 0.789 and 0.777 for Sepsis-2 criteria, 0.838 and 0.704 for Sepsis-3 criteria. CONCLUSIONS: MDW represents a reliable biomarker for sepsis screening.

Tau protein as a diagnostic and prognostic biomarker in amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: To test the hypothesis that total tau (tTau), tau phosphorylated at threonine 181 (pTau) and pTau/tTau ratio in the cerebrospinal fluid (CSF) are diagnostic and prognostic biomarkers of amyotrophic lateral sclerosis (ALS), we performed a retrospective observational study in a large cohort of ALS patients and controls. METHODS: We enrolled 196 ALS patients and 91 controls, who included patients with ALS-mimicking diseases and those with non-neurodegenerative diseases. All patients underwent lumbar puncture for CSF analysis at the time of the diagnostic evaluation or to first referral. We measured tTau and pTau levels in the CSF by chemiluminescence enzyme immunoassay. RESULTS: Patients with ALS showed significantly higher levels of CSF tTau and a lower pTau/tTau ratio than controls (tTau: 245 vs. 146 pg/ml; p < 0.001; pTau/tTau ratio: 0.12 vs. 0.18; p < 0.001, respectively). No differences in pTau levels were detected. Receiver-operating characteristic curve analysis showed a good diagnostic accuracy of tTau and pTau/tTau ratio (tTau: area under the curve [AUC] 0.685, 95% confidence interval [CI] 0.616-0.754, p = 0.039; pTau/tTau ratio: AUC 0.777, 95% CI 0.707-0.848, p < 0.001). Among ALS patients, increased tTau levels were associated with advanced age of onset, increased revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R) score (ΔFS) rate of progression, and spinal onset. Multivariate analysis showed that in ALS patients, this biomarker was an independent negative predictor of overall survival. CONCLUSIONS: Our findings suggest that tTau and pTau/tTau ratio can be diagnostic biomarkers of ALS. In addition, CSF tTau level at diagnosis might play a relevant prognostic role in the disease.

A new tool for sepsis screening in the Emergency Department.

OBJECTIVES: In this study, we developed and evaluated the diagnostic accuracy of the Sepsis Index for early sepsis screening in the Emergency Department (ED). METHODS: Sepsis Index is based on the combination of monocyte distribution width (MDW) and mean monocyte volume (MMV). Sepsis Index≥1 was selected to define sepsis. We tested its diagnostic accuracy in an ED population stratified in four groups: controls, Systemic Inflammatory Response Syndrome (SIRS), infection, and sepsis, according to Sepsis-2 criteria. RESULTS: Patients with sepsis displayed higher median Sepsis Index value than patients without sepsis. At the receiver operating characterictis (ROC) curve analysis for the prediction of sepsis, the area under the curve (AUC) of MDW and Sepsis Index were similar: 0.966 (95%CI 0.947-0.984), and 0.964 (95%CI 0.942-0.985), respectively. Sepsis Index showed increased specificity than MDW (94.7 vs. 90.6%), without any decrease in sensitivity (92.0%). Additionally, LR+ increased from 9.8 (MDW) to 17.4 (Sepsis Index), without any substantial change in LR- (respectively 0.09 vs. 0.08). Finally, PPV increased from 0.286 (MDW) to 0.420 (Sepsis Index). CONCLUSIONS: Sepsis Index improves the diagnostic accuracy of MDW alone for sepsis screening.

Vitamin D and Genetic Susceptibility to Multiple Sclerosis.

Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system (CNS), resulting from the interaction among genetic, epigenetic, and environmental factors. Vitamin D is a secosteroid, and its circulating levels are influenced by environment and genetics. In the last decades, research data on the association between MS and vitamin D status led to hypothesize a possible role for hypovitaminosis D as a risk factor for MS. Some gene variants encoding proteins involved in vitamin D metabolism, transport, and function, which are responsible for vitamin D status alterations, have been related to MS susceptibility. This review explores the current literature on the influence of vitamin D-related genes in MS susceptibility, reporting all single-nucleotide polymorphisms (SNPs) investigated to date in 12 vitamin D pathway genes. Among all, the gene codifying vitamin D receptor (VDR) is the most studied. The association between VDR SNPs and MS risk has been reported by many Authors, with a few studies producing opposite results. Other vitamin D-related genes (including DHCR7/NADSYN1, CYP2R1, CYP27A1, CYP3A4, CYP27B1, CYP24A1, Megalin-DAB2-Cubilin, FGF-23, and Klotho) have been less investigated and achieved more conflicting evidence. Taken together, findings from the studies reviewed cannot clarify whether and to what extent vitamin D-related gene variants can influence MS risk.

Monocyte distribution width (MDW) as a screening tool for sepsis in the Emergency Department.

Objectives The diagnosis of sepsis in the Emergency Department (ED) is challenging and a reliable biomarker is needed. The current study aimed to evaluate the diagnostic accuracy of monocyte distribution width (MDW) for the early identification of sepsis in the ED. Methods We performed a large observational study including consecutive adult patients (≥18 years of age) presenting to the ED between September and November 2019, with an order for complete blood count (CBC) evaluation. A total of 2,215 patients were enrolled and classified based on Sepsis-2 criteria as the control group (1,855), infection group (172), Systemic Inflammatory Response Syndrome (SIRS) group (100), and sepsis group (88). Results MDW levels were higher in patients with sepsis than in all other groups (p<0.001). ROC curve analysis showed an optimal diagnostic accuracy of MDW for sepsis prediction at a cut-off point of 23.5, with an AUC of 0.964, sensitivity and specificity of 0.920 and 0.929, respectively. Conclusions Our findings encourage further investigation to validate the use of MDW as a screening tool for the early identification of patients at risk of sepsis in the ED.

Diagnostic accuracy of cerebrospinal fluid biomarkers measured by chemiluminescent enzyme immunoassay for Alzheimer disease diagnosis.

In the last decades, an important role of cerebrospinal fluid (CSF) biomarkers for Alzheimer disease (AD) diagnosis has emerged. The evaluation of the triad consisting of 42 aminoacid-long amyloid-beta peptide (Aß42), total Tau (tTau) and Tau phosphorylated at threonine 181 (pTau) have been recently integrated into the research diagnostic criteria of AD. For a long time, the enzyme-linked immunosorbent assay (ELISA) has represented the most commonly used method for the measurement of CSF biomarkers levels. This study aimed to assess the diagnostic accuracy of CSF biomarkers, namely Aß42, tTau and pTau and their ratio, measured by fully automated CLEIA assay (Lumipulse). We included 96 patients clinically diagnosed as AD (48) and non-AD (48). All CSF biomarkers levels were measured on Lumipulse G1200 fully automated platform (Fujirebio Inc. Europe, Gent, Belgium). Aß42 levels, 42/40 ratio, 42/tTau ratio, 42/PTau ratio were significantly reduced, and tTau and PTau levels were significantly increased in AD patients in comparison with non-AD patients. The receiving operator curve (ROC) analysis showed good diagnostic accuracy of all CSF biomarkers and their ratios for discriminating AD patients from non-AD patients, with 42/40 ratio having the best AUC (0.724, 95%CI 0.619-0.828; p < 0.001). Our findings support the use of CSF biomarkers measured by CLEIA method on a fully automated platform for AD diagnosis.

Mid-regional pro-adrenomedullin predicts poor outcome in non-selected patients admitted to an intensive care unit.

Background Mortality risk and outcome in critically ill patients can be predicted by scoring systems, such as APACHE and SAPS. The identification of prognostic biomarkers, simple to measure upon admission to an intensive care unit (ICU) is an open issue. The aim of this observational study was to assess the prognostic value of plasma mid-regional pro-adrenomedullin (MR-proADM) at ICU admission in non-selected patients in comparison to Acute Physiology and Chronic Health Evaluation II (APACHEII) and Simplified Acute Physiology Score II (SAPSII) scores. Methods APACHEII and SAPSII scores were calculated after 24 h from ICU admission. Plasma MR-proADM levels were measured by TRACE-Kryptor on admission (T0) and after 24 h (T24). The primary endpoint was intra-hospital mortality; secondary endpoint was length of stay (LOS). Results One hundred and twenty-six consecutive non-selected patients admitted to an ICU were enrolled. Plasma MR-proADM levels were correlated with LOS (r=0.28; p=0.0014 at T0; r=0.26; p=0.005 at T24). Multivariate analysis showed that T0 MR-proADM was a significant predictor of mortality (odds ratio [OR]: 1.27; 95% confidence interval [95%CI]: 1.03-1.55; p=0.022). Receiver operating characteristic curves analysis revealed that MR-proADM on ICU admission identified non-survivors with high accuracy, not inferior to the one of APACHEII and SAPSII scores (area under the curve [AUC]: 0.71; 95%CI: 0.62-0.78; p=0.0002 for MR-proADM; AUC: 0.71; 95%CI: 0.62-0.79; p<0.0001 for APACHEII; AUC: 0.8; 95%CI: 0.71-0.87; p<0.0001 for SAPSII). Conclusions Our findings point out a role of MR-proADM as a prognostic tool in non-selected patients in ICUs being a reliable predictor of mortality and LOS and support its use on admission to an ICU to help the management of critically ill patients.

Glycated albumin as a glycaemic marker in patients with advanced chronic kidney disease and anaemia: a preliminary report.

Background: The association between glycated albumin (GA) and glycaemic status has not been fully described in patients with advanced chronic kidney disease (CKD) in relation to anaemia. The aim of this study was to evaluate the relationship between GA and fasting plasma glucose (FPG) and HbA1c in patients with advanced CKD and to evaluate the influence of anaemia in such relationship. Materials and methods: Patients with CKD stage 4 or 5 were included in the study. eGFR was calculated by the CKD-EPI creatinine equation. Plasma GA was measured by an enzymatic method. Results: Eighty-one patients were included in the study, 46 (57%) were males; the mean age was 67 ± 14 years. HbA1c was correlated with Hb (r = 0.39; p = .0003), and no significant correlation was detected between plasma GA and serum albumin (p = .82). A significant association between FPG and GA (r2 = 0.41; p < .0001), and between FPG and HbA1c (r2 = 0.42; p < .0001) was detected in the whole study population. Patients with moderate/severe anaemia had lower HbA1c than patients with no anaemia, while both FPG and GA were comparable between the two groups. Multivariate regression analysis showed that GA was a significant predictor of FPG in patients with moderate/severe anaemia while HbA1c did not (r2 = 0.55; p < .0001 for the model). Conclusions: GA, alone or in combination with other biomarkers, can be considered for the evaluation of glycaemic status in patients with advanced CKD and severe anaemia.

Cerebrospinal Fluid Analysis in Multiple Sclerosis Diagnosis: An Update.

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system (CNS) with brain neurodegeneration. MS patients present heterogeneous clinical manifestations in which both genetic and environmental factors are involved. The diagnosis is very complex due to the high heterogeneity of the pathophysiology of the disease. The diagnostic criteria have been modified several times over the years. Basically, they include clinical symptoms, presence of typical lesions detected by magnetic resonance imaging (MRI), and laboratory findings. The analysis of cerebrospinal fluid (CSF) allows an evaluation of inflammatory processes circumscribed to the CNS and reflects changes in the immunological pattern due to the progression of the pathology, being fundamental in the diagnosis and monitoring of MS. The detection of the oligoclonal bands (OCBs) in both CSF and serum is recognized as the "gold standard" for laboratory diagnosis of MS, though presents analytical limitations. Indeed, current protocols for OCBs assay are time-consuming and require an operator-dependent interpretation. In recent years, the quantification of free light chain (FLC) in CSF has emerged to assist clinicians in the diagnosis of MS. This article reviews the current knowledge on CSF biomarkers used in the diagnosis of MS, in particular on the validated assays and on the alternative biomarkers of intrathecal synthesis.

Non-Skeletal Activities of Vitamin D: From Physiology to Brain Pathology.

Vitamin D is a secosteroid hormone regulating the expression of almost 900 genes, and it is involved in the regulation of calcium and phosphate metabolism, immune response, and brain development. Low blood vitamin D levels have been reported in patients affected by various diseases. Despite a large amount of literature data, there is uncertainty surrounding the role of vitamin D as a serum biomarker in Alzheimer's disease (AD) and Parkinson's disease (PD). Indeed, the lack of internationally recognized 25(OH)D3 reference measurement procedures and standard materials in the past led to unstandardized serum total 25(OH)D3 results among research and clinical care laboratories. Thus, most of the literature studies reported unstandardized data, which are of little use and make it difficult to draw conclusions of the role of vitamin D in AD and PD. This review summarizes the extra-skeletal actions of vitamin D, focusing its role in immunomodulation and brain function, and reports the issue of lacking standardized literature data concerning the usefulness of vitamin D as a biomarker in AD and PD.

Association of CYP2R1 rs10766197 with MS risk and disease progression.

BACKGROUND: MS is a neurodegenerative autoimmune disease resulting from a complex interaction of genetic and environmental factors. Among these, vitamin D and genetic variants associated with vitamin D-metabolism gain great attention. The aim of our study was to assess five SNPs in NADSYN1 and CYP2R1 genes in relation to serum 25-OH-vitamin D3 levels in MS patients and controls. METHODS: 25-OH-vitamin D3 levels and genotyping of CYP2R1- and NADSYN1-SNPs were investigated both in MS patients and in healthy controls. RESULTS: The analysis revealed lower 25-OH-vitamin D3 concentrations in MS patients than in controls and an association of rs10766197 CYP2R1 SNP with MS risk. After stratifying MS patients according to gender, we found that the minor allele A of rs10766197 had a higher frequency in men in comparison to women affected by MS. Additionally, the presence of allele A in men was associated with disease progression, assessed by EDSS and MSSS scores. CONCLUSION: The findings of our study open new perspectives for a role of CYP2R1 in both risk and progression of MS, with sex-related differences.

The immunological implication of the new vitamin D metabolism.

Vitamin D is a neuro-hormone regulating calcium-phosphate homeostasis, cell proliferation, and immunomodulation. Exogenous and endogenous vitamin D is inactive, and two hydroxylations are required to produce the active hormone. The first hydroxylation is unique to the liver, while the second step occurs in kidney, brain, lung, prostate, placenta, and immune cells. Kidney-derived calcitriol regulates calcium homeostasis. Active hormone produced by brain and immune cells mediates immune system response; lung calcitriol is involved in fighting respiratory tract infections; finally, prostate and placenta vitamin D regulates cells growth and proliferation within such tissues. Immune modulation by vitamin D includes enhancing innate immune response, attenuating and stimulating Th1 and Th2 cell proliferation, respectively, and promoting self-tolerance. Hypovitaminosis D is a common finding in several autoimmune diseases. It is unclear whether hypovitaminosis D could be a consequence or a cause of autoimmune diseases and whether vitamin D supplementation has an impact on these patients. Moreover, there is no consensus on oral cholecalciferol dosage for supplementation. More interventional studies are required to better define how vitamin D could represent both a causation agent in autoimmunity and a target for therapeutic strategies in autoimmune patients.