DOR NEUROPÁTICA EM DOENÇA FALCIFORME: PREVALÊNCIA E ANÁLISE DE POLIMORFISMOS DO RECEPTOR TRPV1

Abstract

Pain is the most frequent symptom and the leading cause of hospitalization in patients with sickle cell disease (SCD). Although traditionally understood as acute and nociceptive, caused by vaso-occlusive crises, recent evidence indicates that about one-third of adults with SCD experience chronic pain throughout their lives. Additionally, characteristics suggestive of neuropathic pain (NP) may be present in this group, although they are often underdiagnosed, highlighting the need for systematic investigation of this type of pain. Understanding of the molecular basis of NP has expanded through the cloning and characterization of ion channel families, such as vanilloid transient receptor potential 1 (TRPV1) receptors. Different polymorphisms in the human TRPV1 gene have been identified, which may explain variations in susceptibility to NP among this population. The aim of this study was to assess the prevalence of DN in patients with DF and the presence of genetic polymorphisms that could be involved in this type of pain. Sociodemographic data and clinical characteristics of the disease were collected, and the DN4 and PainDETECT questionnaires were used to screen for DN in patients at HEMOMAR – Maranhão Hematology and Hemotherapy Center. The polymorphisms rs222749, rs222747, rs8065080, and rs224534 were analyzed using conventional PCR from peripheral blood. A total of 214 patients were studied, with 29% having DN. Age 34 years or older was considered a risk factor for developing DN. The HbSS subtype was most common in the DN group, but this difference was not statistically significant. Pain crises and opioid use were more frequent among those with DN. A strong positive correlation was observed between the two screening tools, demonstrating high agreement in detecting and measuring DN in this population (Pearson's r = 0.87). The polymorphisms rs224534 and rs222747 were not associated with ND, while rs222749 and rs8065080 were not detected in any of the individuals tested, indicating the absence of allelic variation at these loci in the sample studied. It is concluded that neuropathic pain is common among patients with SCD and can be identified using simple, rapid tools suitable for outpatient settings; however, the TRPV1 gene polymorphisms examined did not appear to influence the presence of ND in this population.