Phenotypical characterization of exteroceptive sensation and pain symptoms on diabetic patients.

BACKGROUD: Diabetic neuropathy (DN) is one of the most common complications of diabetes, affecting about half of individuals with the disease. Among the various symptoms of DN, the development of chronic pain stands out and manifests as exacerbated responses to sensorial stimuli. The conventional clinical treatments used for general neuropathy and associated painful symptoms, still brings uncomplete and unsatisfactory pain relief. Patients with neuropathic pain syndromes are heterogeneous. They present with a variety of sensory symptoms and pain qualities which difficult the correct diagnosis of sensory comorbidities and consequently, the appropriate chronic pain management. AIMS: Herein, we aimed to demonstrate the existence of different sensory profiles on diabetic patients by investigating epidemiological and clinical data on the symptomatology of a group of patients with DN. METHODS: This is a longitudinal and observational study, with a sample of 57 volunteers diagnosed with diabetes from outpatient day clinic of Hospital Universitário of the University of São Paulo-Brazil. After being invited and signed the Informed Consent Form (ICF), patients were submitted to clinical evaluation and filled out pain and quality of life questionnaires. They also performed quantitative sensory test (QST) and underwent skin biopsy for correlation with cutaneous neuropathology. RESULTS: Data demonstrate that 70% of the studied sample presented some type of pain, manifesting in a neuropathic or nociceptive way, what has a negative impact on the life of patients with DM. We also demonstrated a positive association between pain and anxiety and depression, in addition to pain catastrophic thoughts. Three distinct profiles were identified in the sample, separated according to the symptoms of pain: (i) subjects without pain; (ii) with mild or moderate pain; (iii) subjects with severe pain. We also identified through skin biopsy that diabetic patients presented advanced sensory impairment, as a consequence of the degeneration of the myelinated and unmyelinated peripheral fibers. This study characterized the painful symptoms and exteroceptive sensation profile in these diabetic patients, associated to a considerable level of sensory degeneration, indicating, and reinforcing the importance of the long-term clinical monitoring of individuals diagnosed with DM, regarding their symptom profiles and exteroceptive sensitivity.

Effect of photobiomodulation on neuropathic pain of diabetic origin: a narrative review of the literature.

To update the literature on the effectiveness of photobiomodulation (PBM) therapy in relieving pain in patients with diabetic peripheral neuropathy (DPN) compared to the effects of post-intervention, control/placebo groups, and other therapies. Search on the following databases: PORTAL PERIODICOS CAPES, PUBMED, GOOGLE ACADEMIC/SCHOLAR, SCOPUS, SCIELO, CENTRAL, and MEDLINE. Manual search: 1) manually capture the references of relevant articles originally selected to be included in the eligible studies. Two independent researchers performed the screening and selection of studies, methods assessment, and data extraction with unblinded authors and impressions. Subsequently, the full text of the originally selected studies was screened. The screening form registered the criteria for excluding literature from the full-text screening. The screening resulted in a total of 1692 citations. Out of these, 1402 citations were examined for titles and abstracts, followed by the removal of duplicated studies; therefore, 68 articles remained for full-text evaluation. 54 articles were excluded after full-text screening. Fourteen articles met the selection criteria, hence being selected and included in this narrative review. PBM showed to be a promising modality in relieving painful symptoms in DPN, especially when implemented in combination with other therapies, by improving the quality of life of diabetic patients.

Photobiomodulation increases cell viability via AKT activation in an in vitro model of diabetes induced by glucose neurotoxicity.

Peripheral neuropathy (PN) is a serious complication of diabetes mellitus (DM) and is known to be resistant to conventional treatment. Photobiomodulation (PBM) is demonstrated to be effective in treating PN and in protecting nerve fiber damage. To better understand the mechanisms underlying the regenerative effects of PBM on diabetic neuropathy, we conducted a study in an in vitro model of diabetes induced by glucose neurotoxicity. Neuro 2A cells (1 × 104 cells/ well; N2A) were cultured in Minimum Essential Medium (MEM) supplemented with high glucose concentrations (100 mM) for 48 h and after the incubation period were submitted to either one or three consecutive applications of PBM, once a day (low-level InGaAlP, continuous wave mode, 660 nm, 30 mW, 1.6 J/cm2, 15 s, per well). Cell viability was measured by MTT method, neurotoxicity by LDH release, neurite outgrowth was evaluated through morphometric analysis, and AKT/ERK protein expression levels were assessed by western blotting. Results demonstrate that PBM increased N2A viability as well as induced neurogenesis observed by the increase in neurite outgrowth being this effect modulated by AKT activation. Data obtained herein reinforce the regenerative potential of PBM in the treatment of PN and strongly suggests that phototherapy should be considered adjuvant in the treatment of diabetes.