¿Por qué degeneran las motoneuronas? Actualización en la patogenia de la esclerosis lateral amiotrófica / Why do motor neurons degenerate? Actualization in the pathogenesis of amyotrophic lateral sclerosis

Introducción: La esclerosis lateral amiotrófica (ELA) es la enfermedad degenerativa de las motoneuronas más frecuente. Aunque un pequeño porcentaje de los casos de ELA tienen un origen familiar y son secundarios a mutaciones en genes concretos, a la gran mayoría de ellos se les presupone un origen multifactorial, sin que su patogenia haya sido completamente aclarada. No obstante, en los últimos años varios estudios han aumentado el conocimiento sobre la patogenia de la enfermedad, planteando la cuestión de si se trata de una proteinopatía, una ribonucleinopatía, una axonopatía o una enfermedad del microambiente neuronal. Desarrollo: En el presente artículo revisamos los trabajos publicados tanto en pacientes como en modelos animales de ELA y discutimos la implicación de los principales procesos celulares que parecen contribuir a su patogenia (procesamiento génico, metabolismo de proteínas, estrés oxidativo, transporte axonal y relación con el microambiente neuronal). Conclusiones: Aunque la patogenia de la ELA dista de estar aclarada, los estudios recientes apuntan a la idea de que hay unos desencadenantes iniciales que varían de unos sujetos a otros, y unas vías finales de degeneración de las motoneuronas que están implicadas en la mayor parte de los casos de enfermedad

Introduction: Amyotrophic lateral sclerosis (ALS) is the most common neurodegenerative disease affecting motor neurons. Although a small proportion of ALS cases are familial in origin and linked to mutations in specific genes, most cases are sporadic and have a multifactorial aetiology. Some recent studies have increased our knowledge of ALS pathogenesis and raised the question of whether this disorder is a proteinopathy, a ribonucleopathy, an axonopathy, or a disease related to the neuronal microenvironment. Development: This article presents a review of ALS pathogenesis. To this end, we have reviewed published articles describing either ALS patients or ALS animal models and we discuss how the main cellular pathways (gene processing, protein metabolism, oxidative stress, axonal transport, relationship with neuronal microenvironment) may be involved in motor neurons degeneration. Conclusions: ALS pathogenesis has not been fully elucidated. Recent studies suggest that although initial triggers may differ among patients, the final motor neurons degeneration mechanisms are similar in most patients once the disease is fully established

Why do motor neurons degenerate? Actualization in the pathogenesis of amyotrophic lateral sclerosis. / ¿Por qué degeneran las motoneuronas? Actualización en la patogenia de la esclerosis lateral amiotrófica.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is the most common neurodegenerative disease affecting motor neurons. Although a small proportion of ALS cases are familial in origin and linked to mutations in specific genes, most cases are sporadic and have a multifactorial aetiology. Some recent studies have increased our knowledge of ALS pathogenesis and raised the question of whether this disorder is a proteinopathy, a ribonucleopathy, an axonopathy, or a disease related to the neuronal microenvironment. DEVELOPMENT: This article presents a review of ALS pathogenesis. To this end, we have reviewed published articles describing either ALS patients or ALS animal models and we discuss how the main cellular pathways (gene processing, protein metabolism, oxidative stress, axonal transport, relationship with neuronal microenvironment) may be involved in motor neurons degeneration. CONCLUSIONS: ALS pathogenesis has not been fully elucidated. Recent studies suggest that although initial triggers may differ among patients, the final motor neurons degeneration mechanisms are similar in most patients once the disease is fully established.

Circulating cytokines in active polymyalgia rheumatica.

OBJECTIVE: To characterise the circulating cytokine profile and the cellular source of circulating cytokines in polymyalgia rheumatica (PMR). METHODS: The study included 34 patients with active untreated PMR and 17 age-matched healthy controls (HC). Circulating cytokines were measured by cytometric bead array and ELISA. Intracellular cytokines were assessed in CD3+ and CD14+ cells by flow cytometry. Cytokines in cell culture supernatants were also determined after polyclonal stimulation of patients' peripheral blood mononuclear cells. RESULTS: Circulating levels of interleukin-6 (IL6) were significantly higher in subjects with active PMR than in HC. Corticosteroid (CS) treatment was followed by a decrease in the level of IL6. Intracellular cytokine staining showed that circulating monocytes did not produce higher amounts of proinflammatory cytokines in patients with PMR than in HC. There was a discordance between serum levels and cytokine-producing monocyte and T cells, and it was not possible to demonstrate a Th1 bias in the peripheral compartment. CONCLUSIONS: Active PMR is characterised by increased serum levels of IL6, but not of other proinflammatory cytokines, that are rapidly suppressed by CS treatment. As circulating monocytes do not show increased production of proinflammatory cytokines, IL6 may be mainly produced in the inflamed tissue. A study of the circulating cytokine profile and its cellular source may provide a clue to new therapeutic options.

Interleukin-12 gene polymorphisim in patients with giant cell arteritis, polymyalgia rheumatica and elderly-onset rheumatoid arthritis.

OBJECTIVE: The cytokine profile suggests that giant cell arteritis (GCA) is a Th1-driven disease, in which local IFN-gamma plays a critical role in the development of a systemic arteritis. IL-12 is a potent inducer of IFN-gamma and is critically involved in biasing an immune response towards a Th1 pathway. The purpose of this study was to investigate whether there was an association between an IL-12 gene polymorphism (-1188 A/C 3UTR) and disease susceptibility for GCA and two other age-related inflammatory conditions, such as polymyalgia rheumatica (PMR) and elderly-onset rheumatoid arthritis (EORA). Furthermore, we attempted to correlate such polymorphism with in vitro IL-12 production. MATERIALS AND METHODS: We analyzed genotypes at -1188 in the 3UTR of the IL-12 promoter by PCR-RFLP in 68 GCA, 138 PMR, and 72 EORA patients as well as in 465 healthy controls (HC). IL-12p70 levels in culture supernatants after stimulation with PMA+Ionomycin was assessed by ELISA. RESULTS: All groups were in Hardy-Weinberg equilibrium. Allelic and gen-omic distribution was not significantly different among the study groups. None of the genetic variants was associated with disease severity. Although the differences were not statistically significant, HC genotypes were associated with distinct IL-12 p70 production. CONCLUSIONS: The IL-12 (-1188 A/C 3UTR) gene polymorphism is not associated with disease susceptibility or severity in three age-related chronic inflammatory syndromes. The production of IL-12 p70 is dependent on the genetic background in HC, although in patients such association may be biased by other unknown factors.

Analysis of peritoneal leukocyte population with different dialysis fluids.

Uremic patients have leukocyte defects. In peritoneal dialysis patients some alterations could be induced by dialysis fluids. We analyzed the changes in immune cells (blood and peritoneal effluent), with the use of three solutions with different biocompatibility. We included 21 patients, 9 on 1 exchange/day icodextrin and 12 with lactate-buffered solutions. A cytometric study (cell subsets, activation markers and toll-like receptors) was performed. In 12 it was repeated after 3 months switch to a low-glucose degradation product (GDP) fluid. With lactate fluids, we observed B-lymphopenia, increase of T-cells and T-lymphocyte activation. In peritoneal effluent more monocytes and activation markers related to blood were found with conventional fluids. Icodextrin induced an increase of blood natural-killer cells, B-lymphocytes and CD8+CD38+ compared with lactate-buffered solution. In peritoneum more monocytes and less B-lymphocytes were found with icodextrin compared with biocompatible solution. Low-GDP fluid induced a decrease in lymphocyte activation markers (blood and effluent). The most biocompatible solution (low-GDP) induced the lowest expression of peritoneal monocytes and TLR4. Low-GDP solutions preserve peritoneum immune defences better, which could be important to avoid peritonitis and preserve peritoneal function. Although we found an association between TLR4 expression and biocompatibility, further investigations are needed in order to determine if such molecule could be a marker of peritoneum dysfunction.

Serum levels of antibodies to Chlamydia pneumoniae and human HSP60 in giant cell arteritis patients.

OBJECTIVE: To measure the serum levels of IgG anti-Chlamydia pneumoniae (C. pneumoniae) and human heat shock protein (hHSP) 60 antibodies in patients with active giant cell arteritis (GCA) and to determine whether such levels decrease with corticosteroid therapy and remission of symptoms. METHODS: IgG anti-C. pneumoniae and anti-hHSP60 antibodies were quantified by commercial and in-house ELISA tests, respectively, in serum samples from 17 GCA patients, 39 polymyalgia rheumatica (PMR) patients and 23 age-matched healthy subjects. RESULTS: Serum IgG anti-hHSP60, but not anti-C. pneumoniae, antibodies were significantly increased in GCA patients in comparison with PMR patients or healthy controls. After steroid therapy, both anti-hHSP60 and -C. pneumoniae antibodies decreased significantly in both groups of patients. CONCLUSIONS: Although some infectious agents have been suggested to participate in GCA pathogenesis, our data do not suggest that C. pneumoniae might be one of them. The production of anti-hHSP60 antibodies is shared in GCA with other systemic diseases and may be triggered by unknown infectious agents and/or other inflammatory factors.