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INTRODUCTION: Chronic pain (CP) negatively impacts the lives of almost 2 billion people worldwide, including approximately 37% of adults in Portugal. As most of these patients are followed by a general practitioner, identifying the prevalence and characterizing the pain of patients who visit primary care units will provide valuable insights into the CP landscape in Portugal. METHODS: To achieve this goal, an observational, cross-sectional study was conducted in 58 primary care units of mainland Portugal between June 2017 and March 2018. Interviews were conducted with 8445 patients, and 578 CP patients were characterized. RESULTS: We observed that one third of patients suffered from CP, and of these, approximately one third felt that their pain management was insufficient. Most of the population was 55 years old or older, retired, and had more than three comorbidities. However, age and the number and type of comorbidities were not predictors of pain intensity. Additionally, most of the population had pain or discomfort that hindered their mobility and the performance of their everyday activities. This decrease in the quality of life led to feelings of anxiety and depression, which were associated with pain intensity. CONCLUSION: Given the high prevalence of CP, strategies to improve the quality of life of these patients and decrease the negative impacts, as well as awareness campaigns to increase the populations' knowledge of this condition, are essential for the suitable and timely treatment of CP.
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Multiple sclerosis (MS) pathology is characterized by neuroinflammation and demyelination. Recently, the inflammatory molecule S100B was identified in cerebrospinal fluid (CSF) and serum of MS patients. Although seen as an astrogliosis marker, lower/physiological levels of S100B are involved in oligodendrocyte differentiation/maturation. Nevertheless, increased S100B levels released upon injury may induce glial reactivity and oligodendrocyte demise, exacerbating tissue damage during an MS episode or delaying the following remyelination. Here, we aimed to unravel the functional role of S100B in the pathogenesis of MS. Elevated S100B levels were detected in the CSF of relapsing-remitting MS patients at diagnosis. Active demyelinating MS lesions showed increased expression of S100B and its receptor, the receptor for advanced glycation end products (RAGE), in the lesion area, while chronic active lesions displayed increased S100B in demyelinated areas with lower expression of RAGE in the rim. Interestingly, reactive astrocytes were identified as the predominant cellular source of S100B, whereas RAGE was expressed by activated microglia/macrophages. Using an ex vivo demyelinating model, cerebral organotypic slice cultures treated with lysophosphatidylcholine (LPC), we observed a marked elevation of S100B upon demyelination, which co-localized mostly with astrocytes. Inhibition of S100B action using a directed antibody reduced LPC-induced demyelination, prevented astrocyte reactivity and abrogated the expression of inflammatory and inflammasome-related molecules. Overall, high S100B expression in MS patient samples suggests its usefulness as a diagnostic biomarker for MS, while the beneficial outcome of its inhibition in our demyelinating model indicates S100B as an emerging therapeutic target in MS.