Humoral immunity response to human endogenous retroviruses K/W differentiates between amyotrophic lateral sclerosis and other neurological diseases

BACKGROUND AND PURPOSE

Human endogenous retroviruses (HERV) K/W seem to play a role in fostering and exacerbation of some neurological diseases, including amyotrophic lateral sclerosis (ALS). Given these findings, the immunity response against HERV-K and HERV-W envelope surface (env-su) glycoprotein antigens in serum and cerebrospinal fluid (CSF) was investigated for ALS, multiple sclerosis (MS) and Alzheimer's disease patients and in healthy controls.

METHODS

Four antigenic peptides derived respectively from HERV-K and HERV-W env-su proteins were studied in 21 definite or probable ALS patients, 26 possible or definite relapsing-remitting MS patients, 18 patients with Alzheimer's disease and 39 healthy controls. An indirect enzyme-linked immunosorbent assay was set up to detect specific antibodies (Abs) against env-su peptides.

RESULTS

Amongst the measured levels of Abs against the four different HERV-K peptide fragments, only HERV-K env-su_19-37 was significantly elevated in ALS compared to other groups, both in serum and CSF. Instead, amongst the Abs levels directed against the four different HERV-W peptide fragments, only HERV-W env-su_93-108 and HERV-W env-su_248-262 were significantly elevated, in the serum and CSF of the MS group compared to other groups. In ALS patients, the HERV-K env-su_19-37 Abs levels were significantly correlated with clinical measures of disease severity, both in serum and CSF.

CONCLUSIONS

Increased circulating levels of Abs directed against the HERV-W env-su_93-108 and HERV-W env-su_248-262 peptide fragments could serve as possible biomarkers in patients with MS. Similarly, increased circulating levels of Abs directed against the HERV-K env-su_19-37 peptide fragment could serve as a possible early novel biomarker in patients with ALS.

Clinical trial: asimadoline in the treatment of patients with irritable bowel syndrome

BACKGROUND

In models of irritable bowel syndrome (IBS), asimadoline, a kappa-opioid agonist, improves pain and abnormal bowel function.

AIM

To evaluate the effects of three doses of asimadoline and placebo in subjects with IBS through a double-blind, randomized, placebo-controlled trial.

METHODS

Patients were randomly assigned to receive asimadoline 0.15, 0.5, 1.0 mg or placebo BID for 12 weeks. The primary efficacy measure was number of months of adequate relief of IBS pain or discomfort, with a prospective plan to evaluate adequate relief data by entry baseline pain and subtype. Several other endpoints were also evaluated.

RESULTS

Five hundred and ninety-six patients were randomized. In the ITT population, statistically significant improvement on the primary endpoint was not seen. However, in diarrhoea-predominant IBS patients with at least baseline moderate pain, asimadoline (0.5 mg) produced significant improvement on total number of months with adequate relief of IBS pain or discomfort (46.7% vs. 20.0%), adequate relief of IBS symptoms (46.7% vs. 23.0%), pain scores (week 12: -1.6 vs. -0.7), pain free days (42.9% vs. 18.0%), urgency and stool frequency (-2.3 vs. -0.3). In patients with alternating IBS, significant improvement was seen on adequate relief endpoints. Asimadoline was well tolerated.

CONCLUSION

Asimadoline warrants further evaluation as a treatment for IBS.

NIH loses in its attempt to patent genetic materials

On June 20,1991, Dr. Craig Venter, then a molecular biologist at the National Institute of Neurological Disorders and Stroke, a member agency of the National Institutes of Health (NIH), revealed that the NIH was filing an application with the Patent and Trademark Office (PTO) to patent 351 genetic fragments sequenced from brain tissues. The first of many applications filed by the NIH during the next two years, the agency also applied to patent the complete set of genes encompassing each fragment. These applications were filed despite the fact that the full gene sequences, their protein products, and their functions were still unknown (several genetic fragments make up a gene, and these fragments code for protein those products that have physiological functions; an example of such a product is insulin).

Molecular evidence for the expression of nicotinic acetylcholine receptor alpha-chain in mouse thymus

The presence and structure of nicotinic acetylcholine receptor (nAChR) in the thymus has been a subject of interest for many years because of its possible role in the pathogenesis of the autoimmune disease myasthenia gravis. Using the polymerase chain reaction with primers specific for the alpha-chain of nAChR (nAChR-alpha), an 880-bp homologous band was found after amplification of cDNA prepared from mouse thymus, thymic medullary and cortical epithelial cell lines, but not from thymocytes or kidney. Sequencing of the polymerase chain reaction product from the thymus and thymic medullary and cortical epithelial lines showed identity with skeletal muscle nAChR-alpha over the region examined. This region includes the domains of the molecule on which B cell and T cell autoantigenic targets have been described. No evidence was found in mouse tissue for the exon 3A, which has been described in human muscle and the human rhabdomyosarcoma cell line TE671. Our results provide evidence at the RNA level for the expression of the nAChR-alpha on stromal cells but not on thymocytes in normal murine thymus and are consistent with a role for intrathymic autoantigen expression in the pathogenesis of myasthenia gravis.

Molecular evidence for the expression of nicotinic acetylcholine receptor alpha-chain in mouse thymus

The presence and structure of nicotinic acetylcholine receptor (nAChR) in the thymus has been a subject of interest for many years because of its possible role in the pathogenesis of the autoimmune disease myasthenia gravis. Using the polymerase chain reaction with primers specific for the alpha-chain of nAChR (nAChR-alpha), an 880-bp homologous band was found after amplification of cDNA prepared from mouse thymus, thymic medullary and cortical epithelial cell lines, but not from thymocytes or kidney. Sequencing of the polymerase chain reaction product from the thymus and thymic medullary and cortical epithelial lines showed identity with skeletal muscle nAChR-alpha over the region examined. This region includes the domains of the molecule on which B cell and T cell autoantigenic targets have been described. No evidence was found in mouse tissue for the exon 3A, which has been described in human muscle and the human rhabdomyosarcoma cell line TE671. Our results provide evidence at the RNA level for the expression of the nAChR-alpha on stromal cells but not on thymocytes in normal murine thymus and are consistent with a role for intrathymic autoantigen expression in the pathogenesis of myasthenia gravis.