The Use of Myelinating Cultures as a Screen of Glycomolecules for CNS Repair.

In vitro cell-based assays have been fundamental in modern drug discovery and have led to the identification of novel therapeutics. We have developed complex mixed central nervous system (CNS) cultures, which recapitulate the normal process of myelination over time and allow the study of several parameters associated with CNS damage, both during development and after injury or disease. In particular, they have been used as a reliable screen to identify drug candidates that may promote (re)myelination and/or neurite outgrowth. Previously, using these cultures, we demonstrated that a panel of low sulphated heparin mimetics, with structures similar to heparan sulphates (HSs), can reduce astrogliosis, and promote myelination and neurite outgrowth. HSs reside in either the extracellular matrix or on the surface of cells and are thought to modulate cell signaling by both sequestering ligands, and acting as co-factors in the formation of ligand-receptor complexes. In this study, we have used these cultures as a screen to address the repair potential of numerous other commercially available sulphated glycomolecules, namely heparosans, ulvans, and fucoidans. These compounds are all known to have certain characteristics that mimic cellular glycosaminoglycans, similar to heparin mimetics. We show that the N-sulphated heparosans promoted myelination. However, O-sulphated heparosans did not affect myelination but promoted neurite outgrowth, indicating the importance of structure in HS function. Moreover, neither highly sulphated ulvans nor fucoidans had any effect on remyelination but CX-01, a low sulphated porcine intestinal heparin, promoted remyelination in vitro. These data illustrate the use of myelinating cultures as a screen and demonstrate the potential of heparin mimetics as CNS therapeutics.

Low sulfated heparins target multiple proteins for central nervous system repair.

The lack of endogenous repair following spinal cord injury (SCI) accounts for the frequent permanent deficits for which effective treatments are absent. Previously, we demonstrated that low sulfated modified heparin mimetics (LS-mHeps) attenuate astrocytosis, suggesting they may represent a novel therapeutic approach. mHeps are glycomolecules with structural similarities to resident heparan sulfates (HS), which modulate cell signaling by both sequestering ligands, and acting as cofactors in the formation of ligand-receptor complexes. To explore whether mHeps can affect the myelination and neurite outgrowth necessary for repair after SCI, we created lesioned or demyelinated neural cell co-cultures and exposed them with a panel of mHeps with varying degrees and positions of their sulfate moieties. LS-mHep7 enhanced neurite outgrowth and myelination, whereas highly sulfated mHeps (HS-mHeps) had attenuating effects. LS-mHeps had no effects on myelination or neurite extension in developing, uninjured myelinating cultures, suggesting they might exert their proregenerating effects by modulating or sequestering inhibitory factors secreted after injury. To investigate this, we examined conditioned media from cultures using chemokine arrays and conducted an unbiased proteomics approach by applying TMT-LC/MS to mHep7 affinity purified conditioned media from these cultures. Multiple protein factors reported to play a role in damage or repair mechanisms were identified, including amyloid betaA4. Amyloid beta peptide (1-42) was validated as an important candidate by treating myelination cultures and shown to inhibit myelination. Thus, we propose that LS-mHeps exert multiple beneficial effects on mechanisms supporting enhanced repair, and represent novel candidates as therapeutics for CNS damage.

Ergotism: Case Report and Review of the Literature.

A case of ergotism is presented to illustrate the role of duplex ultrasonography in the diagnosis and management of this nonatherosclerotic cause of peripheral arterial disease. Historical aspects of ergotism are discussed together with reference to the relative vulnerability of different segments of the arterial circulation. Our case emphasizes the potential for complete reversibility of the vascular changes if recognized early.

Lymphocytic thrombophilic arteritis: a newly described medium-sized vessel arteritis of the skin.

BACKGROUND: We encountered a distinct arteriolar histopathologic finding of lymphocytic vasculitis associated with a hyalinized fibrin ring in vessel lumina. Identical histologic findings have previously been described as macular arteritis. OBSERVATIONS: We describe 5 women (mean age, 25 years; age range, 20-34 years) with persistent, slowly progressive, patchy and reticular hyperpigmentation associated with livedo racemosa affecting predominantly the lower limbs. In the biopsy samples, infiltration of muscular vessel wall by inflammatory cells, affecting small arteries of the dermosubcutaneous junction or superficial subcutis, was present. Of the infiltrate, 90% or more consisted of mononuclear cells, mainly lymphocytes with an admixture of histiocytes. Neutrophils and eosinophils were absent or scant. Inflammation was confined to the vicinity of the vessel and the immediate surrounding panniculus. A concentric fibrin ring involving the entire periphery of the lumina of affected vessels was present in all the patients. Laboratory investigation results revealed that 4 patients had antiphospholipid antibodies in their serum. One of these patients had a heterozygous mutation of the factor V Leiden gene. Conclusion We term this arteritis lymphocytic thrombophilic arteritis to reflect the histologic features that combine lymphocytic vascular inflammation with changes representing a thrombophilic endovasculitis.