“AMYOTROPHIC LATERAL SCLEROSIS AND PROGESTERONE NEUROPROTECTION”

GARGIULO MONACHELLI G; CAMPOS-MELO D; DROPPELMANN C; KELLER B; DE NICOLA A. F.; GONZÁLEZ DENISELLE, M.C.; VOLKENING K; STRONG MJ

Jornada; Resident/Fellow/Graduate Student Research Awards Day 2011.; 2011

Amyotrophic lateral sclerosis (ALS) is a progressive, neurodegenerative disease that primarily affects motor neurons of the spinal cord, brainstem and cerebral cortex. Several reports support that progesterone (PROG) provides neuroprotection in a model of motor neuron degeneration, the Wobbler mouse, and in spinal cord injury, traumatic brain injury, cerebral ischemia and sciatic nerve lesion. Indeed, not only does treatment with exogenous PROG improve the response to various insults, but also endogenous levels at the time of injury are important for neuroprotection. The effects of PROG are mediated through the human nuclear receptor (hPR), which interacts with transcriptional coregulators, moves into nuclear aggregates and regulates gene expression. hPR also regulates transcription via non-genomic pathways such as activation of second messenger signaling cascades. In line with this, we hypothesized: 1) an increase in PROG serum levels in ALS compared to healthy subjects, 2) an association between PROG levels and clinical prognostic and functional features of the disease, 3) the presence of hPR in human spinal cord making it a PROG target tissue and 4) a differential expression of the hPR in ALS versus controls. 27 patients with ALS and 21 healthy controls -matched by age and gender- were selected to assess various hormonal levels. Clinical prognostic features such as age, time to diagnosis, type of onset and survival were analyzed. Likewise, functional respiratory measures including FVC (% of predicted and FVC decline/month), MIP (%) and MEP (%) were considered in the analyses. The expression of hPR (isoform A and B) mRNA transcripts was examined in human cervical and lumbar spinal cord autopsy tissue from controls (neuropathologically normal, three cases) and sporadic ALS (sALS, six cases) by RT-PCR. IHC for the overall hPR expression was also sought for in cervical and lumbar spinal cord tissue of sALS and controls. In ALS patients, serum PROG levels were 2-fold higher in spinal onset patients than bulbar, and they were overall 1.4-fold higher than controls. There was a significant negative correlation between PROG serum levels and age in ALS, a trend toward significant positive correlation with time onset to diagnosis and a positive correlation with MEP (%) and survival time. Other hormones, such as DHEA-S also correlated positively with good prognostic and functional factors, whereas testosterone was associated negatively to them. At the transcript expression level, ALS patients had higher levels of hPR than controls. At the protein level, PR immunoreactivity (IR) did not form aggregates or skeins but rather was diffusely granular. In ALS, IR was differentially increased in astroglial cells, dorsal and ventral roots and vascular structures compared to controls. It was also found in axonal processes and some cell bodies in both patients and controls. The increase of PROG serum levels and its association with positive features of the disease, as well as the higher transcript and protein expression of the hPR in ALS patients, may be an index of a neuroprotective function particularly to counter the process of motor neuron degeneration. Since we found the spinal cord to be a proven target tissue for PROG, this hormone may constitute an attractive candidate for a clinical trial in this disease.