Maintenance of chronicity signatures in fibroblasts isolated from recessive dystrophic epidermolysis bullosa chronic wound dressings under culture conditions.

BACKGROUND: Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a rare inherited skin disease caused by variants in the COL7A1 gene, coding for type VII collagen (C7), an important component of anchoring fibrils in the basement membrane of the epidermis. RDEB patients suffer from skin fragility starting with blister formation and evolving into chronic wounds, inflammation and skin fibrosis, with a high risk of developing aggressive skin carcinomas. Restricted therapeutic options are limited by the lack of in vitro models of defective wound healing in RDEB patients. RESULTS: In order to explore a more efficient, non-invasive in vitro model for RDEB studies, we obtained patient fibroblasts derived from discarded dressings) and examined their phenotypic features compared with fibroblasts derived from non-injured skin of RDEB and healthy-donor skin biopsies. Our results demonstrate that fibroblasts derived from RDEB chronic wounds (RDEB-CW) displayed characteristics of senescent cells, increased myofibroblast differentiation, and augmented levels of TGF-ß1 signaling components compared to fibroblasts derived from RDEB acute wounds and unaffected RDEB skin as well as skin from healthy-donors. Furthermore, RDEB-CW fibroblasts exhibited an increased pattern of inflammatory cytokine secretion (IL-1ß and IL-6) when compared with RDEB and control fibroblasts. Interestingly, these aberrant patterns were found specifically in RDEB-CW fibroblasts independent of the culturing method, since fibroblasts obtained from dressing of acute wounds displayed a phenotype more similar to fibroblasts obtained from RDEB normal skin biopsies. CONCLUSIONS: Our results show that in vitro cultured RDEB-CW fibroblasts maintain distinctive cellular and molecular characteristics resembling the inflammatory and fibrotic microenvironment observed in RDEB patients' chronic wounds. This work describes a novel, non-invasive and painless strategy to obtain human fibroblasts chronically subjected to an inflammatory and fibrotic environment, supporting their use as an accessible model for in vitro studies of RDEB wound healing pathogenesis. As such, this approach is well suited to testing new therapeutic strategies under controlled laboratory conditions.

Chronic pain in Chile: first prevalence report of noncancer chronic pain, fibromyalgia, and neuropathic pain and its associated factors.

ABSTRACT: Although we know chronic pain (CP) affects approximately 30% of people in developed countries, data from Latin America are scarce. Moreover, prevalence of specific CP conditions, such as chronic noncancer pain (CNCP), fibromyalgia (FM), and neuropathic pain (NP), is unknown. To estimate them in Chile, we prospectively enrolled 1945 participants (61.4% women and 38.6% men), aged 38 to 74 years, from an agricultural town who answered a Pain Questionnaire, the Fibromyalgia Survey Questionnaire, and Douleur Neuropathique 4 (DN4) to identify CNCP, FM, and NP, respectively. The estimated prevalence of CNCP was 34.7% (95% CI 32.6; 36.8), with an average duration of 32.3 months (SD ± 56.3), producing deep impairments in daily activities, sleep, and mood. We estimated a prevalence of 3.3% for FM (95% CI 2.5; 4.1) and 12% for NP (95% CI 10.6; 13.4). Female sex, fewer school years, and depressive symptoms were associated with FM and NP, whereas diabetes was only associated with NP. We standardized the results from our sample against the whole Chilean population and found no significant difference to our crude estimates. This is in line with studies from developed countries, highlighting the idea that despite genetic and environmental differences, the conditions that confer risk to CNCP remain stable.

Maintenance of chronicity signatures in fibroblasts isolated from recessive dystrophic epidermolysis bullosa chronic wound dressings under culture conditions

BACKGROUND: Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a rare inherited skin disease caused by variants in the COL7A1 gene, coding for type VII collagen (C7), an important component of anchoring fibrils in the basement membrane of the epidermis. RDEB patients suffer from skin fragility starting with blister formation and evolving into chronic wounds, inflammation and skin fibrosis, with a high risk of developing aggressive skin carcinomas. Restricted therapeutic options are limited by the lack of in vitro models of defective wound healing in RDEB patients. RESULTS: In order to explore a more efficient, non-invasive in vitro model for RDEB studies, we obtained patient fibroblasts derived from discarded dressings) and examined their phenotypic features compared with fibroblasts derived from non-injured skin of RDEB and healthy-donor skin biopsies. Our results demonstrate that fibroblasts derived from RDEB chronic wounds (RDEB-CW) displayed characteristics of senescent cells, increased myofibroblast differentiation, and augmented levels of TGF-ß1 signaling components compared to fibroblasts derived from RDEB acute wounds and unaffected RDEB skin as well as skin from healthy-donors. Furthermore, RDEB-CW fibroblasts exhibited an increased pattern of inflammatory cytokine secretion (IL-1ß and IL-6) when compared with RDEB and control fibroblasts. Interestingly, these aberrant patterns were found specifically in RDEB-CW fibroblasts independent of the culturing method, since fibroblasts obtained from dressing of acute wounds displayed a phenotype more similar to fibroblasts obtained from RDEB normal skin biopsies. CONCLUSIONS: Our results show that in vitro cultured RDEB-CW fibroblasts maintain distinctive cellular and molecular characteristics resembling the inflammatory and fibrotic microenvironment observed in RDEB patients' chronic wounds. This work describes a novel, non-invasive and painless strategy to obtain human fibroblasts chronically subjected to an inflammatory and fibrotic environment, supporting their use as an accessible model for in vitro studies of RDEB wound healing pathogenesis. As such, this approach is well suited to testing new therapeutic strategies under controlled laboratory conditions.

Characterisation of the pathophysiology of neuropathy and sensory dysfunction in a mouse model of recessive dystrophic epidermolysis bullosa.

ABSTRACT: Recessive dystrophic epidermolysis bullosa (RDEB) is a rare genetic condition in which mutations in the type VII collagen gene ( COL7A1 ) lead to decreased expression of this anchoring protein of the skin, causing the loss of stability at the dermo-epidermal junction. Most patients with RDEB experience neuropathic pain and itch due to the development of a small fibre neuropathy, characterised by decreased intraepidermal innervation and thermal hypoaesthesia. To understand the physiopathology of this neuropathy, we used a mouse model of RDEB (Col7a1 flNeo/flNeo ) and performed a detailed characterisation of the somatosensory system. Col7a1 flNeo/flNeo mice showed a decrease in heat sensitivity, an increase in spontaneous scratching, and a significant decrease in intraepidermal nerve fibre density in the hindpaw; these changes were distal because there was no significant loss of unmyelinated or myelinated fibres in the nerve trunk. Of interest, we observed a decrease in axon diameter in both myelinated and unmyelinated fibres. This axonal damage was not associated with inflammation of the dorsal root ganglion or central projection targets at the time of assessment. These results suggest that in RDEB, there is a distal degeneration of axons produced by exclusive damage of small fibres in the epidermis, and in contrast with traumatic and acute neuropathies, it does not induce sustained neuroinflammation. Thus, this animal model emphasizes the importance of a healthy cutaneous environment for maintenance of epidermal innervation and faithfully replicates the pathology in humans, offering the opportunity to use this model in the development of treatments for pain for patients with RDEB.

The Genetics of Neuropathic Pain from Model Organisms to Clinical Application.

Neuropathic pain (NeuP) arises due to injury of the somatosensory nervous system and is both common and disabling, rendering an urgent need for non-addictive, effective new therapies. Given the high evolutionary conservation of pain, investigative approaches from Drosophila mutagenesis to human Mendelian genetics have aided our understanding of the maladaptive plasticity underlying NeuP. Successes include the identification of ion channel variants causing hyper-excitability and the importance of neuro-immune signaling. Recent developments encompass improved sensory phenotyping in animal models and patients, brain imaging, and electrophysiology-based pain biomarkers, the collection of large well-phenotyped population cohorts, neurons derived from patient stem cells, and high-precision CRISPR generated genetic editing. We will discuss how to harness these resources to understand the pathophysiological drivers of NeuP, define its relationship with comorbidities such as anxiety, depression, and sleep disorders, and explore how to apply these findings to the prediction, diagnosis, and treatment of NeuP in the clinic.

Recessive dystrophic epidermolysis bullosa results in painful small fibre neuropathy.

Small fibres in the skin are vulnerable to damage in metabolic or toxic conditions such as diabetes mellitus or chemotherapy resulting in small fibre neuropathy and associated neuropathic pain. Whether injury to the most distal portion of sensory small fibres due to a primary dermatological disorder can cause neuropathic pain is still unclear. Recessive dystrophic epidermolysis bullosa (RDEB) is a rare condition in which mutations of proteins of the dermo-epidermal junction lead to cycles of blistering followed by regeneration of the skin. Damage is exclusive to the skin and mucous membranes, with no known direct compromise of the nervous system. It is increasingly recognized that most RDEB patients experience daily pain, the aetiology of which is unclear but may include inflammation (in the wounds), musculoskeletal (due to atrophy and retraction scars limiting movement) or neuropathic pain. In this study we investigated the incidence of neuropathic pain and examined the presence of nerve dysfunction in RDEB patients. Around three quarters of patients presented with pain of neuropathic characteristics, which had a length-dependent distribution. Quantitative sensory testing of the foot revealed striking impairments in thermal detection thresholds combined with an increased mechanical pain sensitivity and wind up ratio (temporal summation of noxious mechanical stimuli). Nerve conduction studies showed normal large fibre sensory and motor nerve conduction; however, skin biopsy showed a significant decrease in intraepidermal nerve fibre density. Autonomic nervous system testing revealed no abnormalities in heart rate and blood pressure variability however the sympathetic skin response of the foot was impaired and sweat gland innervation was reduced. We conclude that chronic cutaneous injury can lead to injury and dysfunction of the most distal part of small sensory fibres in a length-dependent distribution resulting in disabling neuropathic pain. These findings also support the use of neuropathic pain screening tools in these patients and treatment algorithms designed to target neuropathic pain.

Exposición subcutánea a lindano: reporte de caso / Subcutaneous exposure to lindane: case report

El lindano es un insecticida organoclorado perteneciente a la familia de los hexaclorociclohexanos. A pesar de su toxicidad, es usado frecuentemente para el tratamiento de la pediculosis y sarna en humanos, por su bajo costo y amplia disponibilidad. En los principales efectos clínicos de la exposición aguda a lindano, se encuentran: excitación, convulsiones, cefalea, hipertemia, disnea, depresión respiratoria, hipotensión, arritmias, mareos, náuseas, vómitos, entre otras [1]. Se han descrito diferentes vías de absorción del lindano, siendo la más frecuente la exposición dérmica [2], y luego la ingestión e inhalación. Sin embargo, hasta el momento no ha habido reportes de exposición por vía subcutánea. Este reporte presenta un caso en que la exposición se produjo vía subcutánea.