Riluzole prevents oxaliplatin-induced cold allodynia via inhibition of overexpression of transient receptor potential melastatin 8 in rats.

Oxaliplatin causes acute cold hypersensitivity in most patients. We previously reported oxalate derived from oxaliplatin induced cold allodynia via overexpression of transient receptor potential melastatin 8 (TRPM8) in the dorsal root ganglion (DRG) in rats. In this study, we examined the effect of riluzole on oxaliplatin-induced cold allodynia. In cultured DRG neurons, riluzole suppressed oxalate-induced increase of the number of menthol (TRPM8 agonist)-sensitive cells. Moreover, riluzole prevented cold allodynia and increase in levels of TRPM8 mRNA in oxaliplatin-treated rats. These results suggest that riluzole prevents oxaliplatin-induced cold allodynia via inhibition of TRPM8 overexpression in the DRG.

Síndromes periódicos asociados a criopirina: etiopatogenia, características clínicas, diagnóstico y tratamiento / Cryopiryn-associated peryodic syndrome: etiopathogenesis, clinical features, diagnosis and treatment

Los desórdenes autoinflamatorios monogénicos comprenden un grupo de enfermedades caracterizadas por episodios recurrentes y espontáneos de fiebre e inflamación sistémica, en ausencia de infección, autoanticuerpos o células T específicas para antígenos propios (autorreactivas). Estas condiciones se deben a mutaciones en genes que codifican para proteínas que son claves en la regulación de la respuesta inflamatoria innata y se consideran como inmunodeficiencias primarias. Las enfermedades que comprenden estos síndromes representan un espectro clínico de diferentes mutaciones, con ganancia de función, de un gen denominado NLRP3 o CIAS1 que codifica para la proteína criopirina, de ahí que estos desórdenes sean también conocidos con el nombre de criopirinopatías. Dentro de estos se encuentran los síndromes periódicos asociados a criopirina que incluyen tres enfermedades: el síndrome autoinflamatorio familiar inducido por frío; el síndrome de Muckle-Wells y el síndrome crónico, infantil, neurológico, cutáneo y articular. Clínicamente se caracterizan por rash tipo urticariano, fiebre periódica, inflamación a nivel del sistema nervioso central, artropatía, manifestaciones oculares y riesgo de amiloidosis como complicación a largo plazo. La función clave de la criopirina en la liberación de la IL-β sugiere el criterio racional de implementar terapias anti-IL-1 para el tratamiento de estos síndromes. La administración de drogas como anakinra, canakinumab y rilonacept muestra un efecto marcado sobre el control de las manifestaciones inflamatorias, clínicas y de los parámetros de laboratorio en estos síndromes. Se describe la etiopatogenia de estas entidades, sus principales características clínicas, el diagnóstico y el tratamiento(AU)

Monogenic autoinflammatory disorders encompass a group of diseases characterized by spontaneous and recurring fever and systemic inflammation in the absence of infection, autoantibodies or specific T cells for self antigens (self-reactive). These conditions are caused by mutations in genes encoding proteins that play a key role in the regulation of innate inflammatory response and are considered primary immunodeficiencies. Diseases comprising these syndromes represent a different clinical spectrum of mutations, with gain of function of a gene called NLRP3 or CIAS1 encoding cryopyrin protein, hence these disorders are also known under the name cryopyrinpathies. Among these are the cryopyrin-associated periodic syndrome which include three conditions: familial cold autoinflammatory syndrome; Muckle-Wells syndrome and chronic infantile neurological, cutaneous and articular syndrome. In clinical terms, it is characterized by urticarial rash, periodic fever, inflammation of central nervous system (CNS), arthropathy, ocular manifestations and risk of amyloidosis as a long-term complication. The key role of cryopirin in the release of IL-β suggests rational approach to implement anti-IL-1 therapy for the treatment of these syndromes. The administration of drugs such as anakinra, canakinumab, and rilonacept shows a marked effect on the control of inflammatory manifestations, as well as clinical and laboratory parameters in these syndromes effect. The pathogenesis of these entities, as well as their main clinical features, diagnosis and treatment are described(AU)

The preventive effect of resiniferatoxin on the development of cold hypersensitivity induced by spinal nerve ligation: involvement of TRPM8.

BACKGROUND: Resiniferatoxin (RTX) is a potent analog of capsaicin and activates transient receptor potential (TRP) vanilloid type (TRPV) 1. In the current study, we investigated the preventive effect of perineural RTX on the development of cold hypersensitivity induced by spinal nerve ligation (SNL) in rats. Furthermore, we examined the association between the expression level of TRPV1, TRP ankyrin type (TRPA) 1 and TRP melastatin type (TRPM) 8 in the dorsal root ganglion (DRG) and cold hypersensitivity after SNL. RESULTS: RTX pretreatment prevented the development of SNL-induced hypersensitivity to mechanical, thermal, and cold stimuli. Western blot analysis 4 weeks after RTX pretreatment showed that RTX pretreatment decreased the protein expression level of SNL-induced TRPM8, but not TRPV1 or TRPA1, in the DRG of SNL rats. Immunofluorescent analysis revealed that up-regulated TRPM8-stained neurons after SNL co-localized with neurofilament 200-positive neurons located in the DRG. CONCLUSIONS: Pretreatment with perineural RTX significantly inhibits SNL-induced mechanical, thermal, and cold hypersensitivity. The antinociceptive effect of perineural RTX, especially on cold hypersensitivity, may be related to the suppression of TRPM8 expression in DRG.

¿Dermatopatología alérgica o una enfermedad rara? / Allergic dermatopathology or a rare disease?

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Oxaliplatin administration increases expression of the voltage-dependent calcium channel α2δ-1 subunit in the rat spinal cord.

Oxaliplatin is a chemotherapeutic agent that is effective against various types of cancer including colorectal cancer. Acute cold hyperalgesia is a serious side effect of oxaliplatin treatment. Although the therapeutic drug pregabalin is beneficial for preventing peripheral neuropathic pain by targeting the voltage-dependent calcium channel α2δ-1 (Cavα2δ-1) subunit, the effect of oxaliplatin-induced acute cold hypersensitivity is uncertain. To analyze the contribution of the Cavα2δ-1 subunit to the development of oxaliplatin-induced acute cold hypersensitivity, Cavα2δ-1 subunit expression in the rat spinal cord was analyzed after oxaliplatin treatment. Behavioral assessment using the acetone spray test showed that 6 mg/kg oxaliplatin-induced cold hypersensitivity 2 and 4 days later. Oxaliplatin-induced acute cold hypersensitivity 4 days after treatment was significantly inhibited by pregabalin (50 mg/kg, p.o.). Oxaliplatin (6 mg/kg, i.p.) treatment increased the expression level of Cavα2δ-1 subunit mRNA and protein in the spinal cord 2 and 4 days after treatment. Immunohistochemistry showed that oxaliplatin increased Cavα2δ-1 subunit protein expression in superficial layers of the spinal dorsal horn 2 and 4 days after treatment. These results suggest that oxaliplatin treatment increases Cavα2δ-1 subunit expression in the superficial layers of the spinal cord and may contribute to functional peripheral acute cold hypersensitivity.

Novel TRPM8 antagonist attenuates cold hypersensitivity after peripheral nerve injury in rats.

Abnormal cold sensitivity is a common feature of a range of neuropathies. In the murine somatosensory system, multiple aspects of cold sensitivity are dependent on TRPM8, both short term and in response to peripheral nerve injury. The specialized nature of cold-sensitive afferents and the restricted expression of TRPM8 render it an attractive target for the treatment of cold hypersensitivity. This current study examines the effect of a novel TRPM8 antagonist (M8-An) in naive and spinal nerve-ligated rats through behavioral and in vivo electrophysiological approaches. In vitro, M8-An inhibited icilin-evoked Ca(2+) currents in HEK293 cells stably expressing human TRPM8 with an IC(50) of 10.9 nM. In vivo, systemic M8-An transiently decreased core body temperature. Deep dorsal horn recordings were made in vivo from neurons innervating the hind paw. M8-An inhibited neuronal responses to innocuous and noxious cooling of the receptive field in spinal nerve-ligated rats but not in naive rats. No effect on neuronal responses to mechanical and heat stimulation was observed. In addition, M8-An also attenuated behavioral responses to cold but not mechanical stimulation after nerve ligation without affecting the uninjured contralateral response. The data presented here support a contribution of TRPM8 to the pathophysiology of cold hypersensitivity in this model and highlight the potential of the pharmacological block of TRPM8 in alleviating the associated symptoms.