RESUMEN
The immune system is involved in the development of neuropathic pain. In particular, the infiltration of T-lymphocytes into the spinal cord following peripheral nerve injury has been described as a contributor to sensory hypersensitivity. We used the spared nerve injury (SNI) model of neuropathic pain in Sprague Dawley adult male rats to assess proliferation, and/or protein/gene expression levels for microglia (Iba1), T-lymphocytes (CD2) and cytotoxic T-lymphocytes (CD8). In the dorsal horn ipsilateral to SNI, Iba1 and BrdU stainings revealed microglial reactivity and proliferation, respectively, with different durations. Iba1 expression peaked at D4 and D7 at the mRNA and protein level, respectively, and was long-lasting. Proliferation occurred almost exclusively in Iba1 positive cells and peaked at D2. Gene expression observation by RT-qPCR array suggested that T-lymphocytes attracting chemokines were upregulated after SNI in rat spinal cord but only a few CD2/CD8 positive cells were found. A pronounced infiltration of CD2/CD8 positive T-cells was seen in the spinal cord injury (SCI) model used as a positive control for lymphocyte infiltration. Under these experimental conditions, we show early and long-lasting microglia reactivity in the spinal cord after SNI, but no lymphocyte infiltration was found.
Asunto(s)
Microglía/fisiología , Traumatismos de los Nervios Periféricos/complicaciones , Traumatismos de la Médula Espinal/etiología , Linfocitos T/fisiología , Animales , Antígenos CD2/genética , Antígenos CD8/genética , Proteínas de Unión al Calcio/genética , Proliferación Celular , Quimiocinas/inmunología , Modelos Animales de Enfermedad , Expresión Génica , Masculino , Proteínas de Microfilamentos/genética , Microglía/metabolismo , Microglía/patología , Neuralgia , Traumatismos de los Nervios Periféricos/inmunología , Ratas , Ratas Sprague-Dawley , Traumatismos de la Médula Espinal/inmunología , Traumatismos de la Médula Espinal/fisiopatología , Linfocitos T/metabolismo , Linfocitos T/patologíaRESUMEN
Despite their high prevalence, associated disability and seemingly rich pharmacopeia, the various forms of chronic pain remain frequently intractable. The past decade witnessed the rise of a concept stating that non-neuronal cells of the central nervous system, astrocytes and microglia, are crucial elements in pathological pain. This review gathers and summarizes the experimental data underpinning this theory in animal models and addresses their pertinence in humans. The potential opportunities and constraints of glial inhibition are exposed and compared to more moderate strategies of selective modulation. This therapeutic hope is particularly highlighted in our discussion of the first completed clinical trials employing glial inhibitors in the treatment of chronic pain.
Asunto(s)
Dolor Crónico/fisiopatología , Neuroglía , Dolor Intratable/fisiopatología , Analgésicos no Narcóticos/uso terapéutico , Animales , Astrocitos , Sistema Nervioso Central/fisiopatología , Dolor Crónico/diagnóstico , Dolor Crónico/tratamiento farmacológico , Dolor Crónico/epidemiología , Ensayos Clínicos como Asunto , Medicina Basada en la Evidencia , Humanos , Microglía , Neuroglía/efectos de los fármacos , Dolor Intratable/diagnóstico , Dolor Intratable/tratamiento farmacológico , Dolor Intratable/epidemiología , Resultado del TratamientoRESUMEN
PURPOSE: The development of liver metastases from breast cancer is associated with a very poor prognosis, estimated at 4 months median survival. Since treatment with many chemotherapeutic agents is relatively contraindicated, we assessed the safety, tolerability and potential efficacy of combination chemotherapy with vinorelbine and cisplatin (ViP). METHOD: Pilot study in 11 patients with histologically confirmed breast carcinoma, radiological evidence of liver metastases and serum bilirubin greater than 1.5 times the upper limit of normal. Patients received up to six cycles of cisplatin (75 mg/m2) every 21 days and vinorelbine (20 mg/m2) on days 1 and 8 of every 21-day cycle. Measurement of liver lesions was performed on CT scan every 8 weeks into treatment. RESULTS: The most frequently reported adverse event was myelosuppression. Other adverse effects included nausea, vomiting and mild neurotoxicity. Two patients died after one treatment with ViP, one of whom suffered an intracerebral haemorrhage that was possibly treatment-related. Improvement in liver function tests was observed in 10 patients, and mean time to normalization of bilirubin levels was 36 days. Partial responses were documented radiologically in 7 out of 11 patients treated. Median overall survival from trial entry was 6.5 months (range 11-364 days), with one patient alive 13 months from trial entry. CONCLUSION: Normalization of liver function is possible with ViP treatment of metastatic breast cancer, offering the potential to prolong survival. Phase II clinical trials of this regimen in this patient group should include measurement of quality of life in order to assess risk versus benefit.