RESUMEN
BACKGROUND: Peripheral nerves can regenerate and restore function after injury but this process is hindered by many factors including chronic denervation, motor end-plate resorption and Schwann cell senescence. Forelimb injury models in rodents are becoming increasingly popular as they more accurately reflect the physiology and biomechanics of upper extremity nerve injuries. However several aspects of this surgical model remain poorly characterized. NEW METHOD: C57Bl/6 mice underwent enumeration of median nerve motor and sensory neuron pools using retrograde labeling with or without nerve transection. Distal histomorphometry of uninjured mouse median nerves was also examined. Baseline reference values of volitional forelimb grip strength measurements were determined and the rate of neural elongation was also estimated. RESULTS: We identified 1363 ± 165 sensory and 216 ± 16 motor neurons within the uninjured dorsal root ganglia (DRG) and ventral spinal cord, respectively. Eight days following injury, approximately 34% of motoneurons had elongated a distance of 5 mm beyond the repair site 8 days following injury. Volitional grip strength decreased 50% with unilateral median nerve transection and was negligible with contralateral flexor tendon tenotomy. COMPARISON WITH EXISTING METHOD: Our spinal cord and DRG harvesting technique presented here was technically straightforward and reliable. Estimates of motor and sensory neuron numbers for the mouse median nerve compared favourably with studies using intramuscular injection of retrograde neurotracer. Histomorphometry data was consistent with and reinforced reference values in the literature. CONCLUSIONS: This study provides data that further develops an increasingly popular surgical model for studying peripheral nerve injury and repair.
Asunto(s)
Nervio Mediano , Traumatismos de los Nervios Periféricos , Ratones , Animales , Células Receptoras Sensoriales , Neuronas Motoras/fisiología , Ganglios Espinales , Regeneración Nerviosa/fisiologíaRESUMEN
AIM: Sarcoidosis is a multisystem granulomatous disease. This condition has a documented association with the diagnosis of melanoma and can be induced in melanoma patients receiving anti-neoplastic therapy. We evaluated a case series of melanoma patients who developed immunotherapy-induced sarcoidosis. METHODS: Three patients with melanoma (n = 1 resected Stage III, n = 2 metastatic) treated with anti-programmed cell death (PD)-1 antibody therapy at two institutions developed biopsy-proven sarcoidosis. We used mass cytometry to determine expression of the relevant chemokine receptors (CR) by peripheral blood mononuclear cells for two of the three patients who developed sarcoidosis and 13 melanoma patients who did not. Blood samples were collected before receiving PD-1 checkpoint inhibitor therapy. RESULTS: Immunophenotypic analysis demonstrated abnormally high numbers of circulating Th17.1 (CCR6+ CCR4- CXCR3+ CCR10- ) cells prior to commencing PD-1 checkpoint inhibitor therapy in five of 15 melanoma patients, including both the patients who developed sarcoidosis during the course of therapy. CONCLUSION: Our findings support prior literature implicating Th17.1 cells in the pathogenesis of sarcoidosis. However, we demonstrate these findings in patients with melanoma prior to administration of checkpoint therapy and before the onset of clinically symptomatic sarcoidosis. The identification of elevated Th17.1 cells in melanoma patients who have not developed sarcoidosis may reflect the established association between melanoma and sarcoidosis. With some patients receiving these agents over a prolonged period, the clinical course of immunotherapy-induced sarcoidosis is uncertain.
Asunto(s)
Antineoplásicos Inmunológicos/efectos adversos , Inmunofenotipificación , Inmunoterapia/efectos adversos , Melanoma/tratamiento farmacológico , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Sarcoidosis Pulmonar/inducido químicamente , Neoplasias Cutáneas/tratamiento farmacológico , Células Th17/efectos de los fármacos , Corticoesteroides/uso terapéutico , Adulto , Anciano , Biomarcadores/sangre , Biopsia , Femenino , Humanos , Masculino , Melanoma/sangre , Melanoma/inmunología , Melanoma/secundario , Persona de Mediana Edad , Estadificación de Neoplasias , Fenotipo , Tomografía de Emisión de Positrones , Valor Predictivo de las Pruebas , Receptor de Muerte Celular Programada 1/inmunología , Sarcoidosis Pulmonar/sangre , Sarcoidosis Pulmonar/diagnóstico , Sarcoidosis Pulmonar/tratamiento farmacológico , Neoplasias Cutáneas/sangre , Neoplasias Cutáneas/inmunología , Neoplasias Cutáneas/patología , Células Th17/inmunología , Células Th17/metabolismo , Tomografía Computarizada por Rayos X , Resultado del TratamientoRESUMEN
Elevating levels of nerve growth factor (NGF) can have pronounced effects on the survival and maintenance of distinct populations of neurons. We have generated a line of transgenic mice in which NGF is expressed under the control of the smooth muscle α-actin promoter. These transgenic mice have augmented levels of NGF protein in the descending colon and urinary bladder, so these tissues display increased densities of NGF-sensitive sympathetic efferents and sensory afferents. Here we provide a thorough examination of sympathetic and sensory axonal densities in the descending colon and urinary bladder of NGF transgenic mice with and without the expression of the p75 neurotrophin receptor (p75NTR). In response to elevated NGF levels, sympathetic axons (immunostained for tyrosine hydroxylase) undergo robust collateral sprouting in the descending colon and urinary bladder of adult transgenic mice (i.e., those tissues having smooth muscle cells); this sprouting is not augmented in the absence of p75NTR expression. As for sensory axons (immunostained for calcitonin gene-related peptide) in the urinary bladders of transgenic mice, fibers undergo sprouting that is further increased in the absence of p75NTR expression. Sympathetic axons are also seen invading the sensory ganglia of transgenic mice; these fibers form perineuronal plexi around a subpopulation of sensory somata. Our results reveal that elevated levels of NGF in target tissues stimulate sympathetic and sensory axonal sprouting and that an absence of p75NTR by sensory afferents (but not by sympathetic efferents) leads to a further increase of terminal arborization in certain NGF-rich peripheral tissues.
Asunto(s)
Músculo Liso/metabolismo , Factor de Crecimiento Nervioso/biosíntesis , Receptor de Factor de Crecimiento Nervioso/metabolismo , Células Receptoras Sensoriales/metabolismo , Sistema Nervioso Simpático/metabolismo , Animales , Axones/fisiología , Western Blotting , Recuento de Células , Colon/metabolismo , Femenino , Técnica del Anticuerpo Fluorescente , Ratones , Ratones Transgénicos , Fibras Nerviosas/metabolismo , Factor de Crecimiento Nervioso/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Vejiga Urinaria/metabolismoRESUMEN
Nerve growth factor (NGF) and its precursor proNGF are perhaps the best described growth factors of the mammalian nervous system. There remains, however, a paucity of information regarding the precise cellular sites of proNGF/NGF synthesis. Here we report the generation of transgenic mice in which the NGF promoter controls the ectopic synthesis of enhanced green fluorescent protein (EGFP). These transgenic mice provide an unprecedented resolution of both neural cells (e.g., neocortical and hippocampal neurons) and non-neural cells (e.g., renal interstitial cells and thymic reticular cells) that display NGF promoter activity from postnatal development to adulthood. Moreover, the transgene is inducible by injury. At 2 days after sciatic nerve ligation, a robust population of EGFP-positive cells is seen in the proximal nerve stump. These transgenic mice offer novel insights into the cellular sites of NGF promoter activity and can be used as models for investigating the regulation of proNGF/NGF expression after injury.
Asunto(s)
Proteínas Fluorescentes Verdes/metabolismo , Factor de Crecimiento Nervioso/genética , Factor de Crecimiento Nervioso/metabolismo , Regiones Promotoras Genéticas , Animales , Encéfalo/citología , Encéfalo/metabolismo , Femenino , Genes Reporteros , Proteínas Fluorescentes Verdes/genética , Masculino , Ratones , Ratones Transgénicos , ARN Mensajero/metabolismo , Nervio Ciático/citología , Nervio Ciático/lesiones , Nervio Ciático/metabolismo , Distribución Tisular , TransgenesRESUMEN
Eye and adnexal involvement in epidermolysis bullosa can range from symptoms of mild irritation resulting from conjunctival involvement to severe cicatrization of the ocular surface and adnexa. We describe a unique case of granulation tissue in the eyelid margin and conjunctiva in a patient with junctional epidermolysis bullosa. The eyelid granulation tissue resembled granulomas that seen in laryngo-onycho-cutaneous syndrome, which is caused by a mutation in an isoform of the LAMA3 gene, LAMA3a. On investigation, our patient had a combination of a unique mutation in LAMA3 and the mutation I17N in LAMA3a, providing further evidence that laryngo-onycho-cutaneous syndrome is a variant of junctional EB.