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Biomedical subjects

D A Compston

Publications and source records attributed to D A Compston.

At least 19 recordsLinked to original sources
PubMed2002

Microglia-derived IGF-2 prevents TNFalpha induced death of mature oligodendrocytes in vitro.

Insulin-like growth factor-2 (IGF-2) present in media conditioned by non-activated and interferon gamma (IFN gamma)-treated microglia reduces galactocerebroside(+) (GalC) oligodendrocyte apoptosis in cultures derived both from the CG4 cell line and primary rat cortices. Microglia-derived IGF-2 also acts in each culture system to block GalC(+) oligodendrocyte toxicity resulting from soluble microglial-derived tumour necrosis factor alpha (TNF alpha). IGF-2 inhibits TNF alpha-induced c-Jun kinase (JNK) activation of the CG4 cell line. Microglial activation results in the release of soluble factors that are potentially toxic to oligodendrocytes but this may be offset by the production of soluble factors that protect these vulnerable cells. Allowing for extrapolation of these in vitro findings to intact tissue, our observations suggest one mechanism for limiting bystander damage in the context of inflammatory brain disease.

Animals↗
PubMed2001

Patterns of disease in concordant parent-child pairs with multiple sclerosis.

BACKGROUND: Although the exact etiology of MS remains elusive, there is good evidence that genetic factors play an important role. These factors are likely to be polygenic, exerting both independent and interactive effects on the expression of MS. They may determine susceptibility and/or shape the clinical course. METHODS: The authors studied clinical phenotype in 245 concordant parent-child pairs recruited from a national register of familial disease over a 10-year period. Data were examined in order to determine the effect of parental sex on expression of disease in the offspring. RESULTS: Allowing for the observed sex ratio of 2.6 F:1 M in this group of patients, sex pairings of parents and offspring were close to those expected. When assessed independently there was no evidence that either the sex of the affected offspring or the line of inheritance influenced disability, age at onset, or disease course. However, trends were observed toward greater disability and an increased frequency of primary progressive disease in offspring of affected fathers and an earlier age at onset in offspring of affected mothers. The highest mean Expanded Disability Status Scale score was observed in male offspring of affected fathers (5.64) and this group was also more likely to have primary progressive disease (OR 1.92). Thirty-one percent of families had an additionally affected offspring with no preferential maternal or paternal transmission. CONCLUSIONS: In offspring of concordant parent-child families with MS who are at high risk of inheriting increased numbers of susceptibility genes there is no evidence for a parent of origin effect distorting sex ratios in affected offspring, but parent of origin may influence disability and disease course as well as increasing the risk to additional offspring within the same family. The mechanism of these effects is not clear but may result from interactions between genes encoded at different loci (epistasis), which each independently influence susceptibility and phenotype.

Adolescent↗
PubMed2001

Infratentorial hypointense lesion volume on T1-weighted magnetic resonance imaging correlates with disability in patients with chronic cerebellar ataxia due to multiple sclerosis.

In multiple sclerosis (MS), hypointense lesions on T1-weighted magnetic resonance imaging are thought to represent areas of tissue disruption and axonal loss. In previous studies of MS patients, infratentorial T1 hypointense lesions were found to be rare. In MS patients selected to have chronic cerebellar ataxia, we have determined the extent of infratentorial T1 hypointense lesions and their relationship with disability. We recruited nine patients with chronic cerebellar ataxia due to MS. An expanded disability status scale (EDSS) assessment was performed on each. The patients' brains were then imaged with axial-oblique dual-echo fast spin-echo and contrast-enhanced T1-weighted conventional spin-echo sequences. The number and total volume of infratentorial high-signal lesions on T2-weighted images and infratentorial hypointense lesions on T1-weighted images were calculated by a blinded observer using a computer-assisted contouring technique. A total of 96 infratentorial high-signal lesions were present, of which 62 (64.6%) appeared isointense and 34 (35.4%) hypointense with respect to the surrounding brain substance on the T1-weighted images. There was a median of 3 (range 0-10) and median volume of 0.43 ml (range 0-0.85 ml) infratentorial T1 hypointense lesions per patient. The EDSS score correlated with both the number (r=0.68, p=0.043) and the volume per patient (r=0.89, p=0.001) of infratentorial T1 hypointense but not T2 high-signal lesions. Infratentorial T1 hypointense lesions are often seen in patients with MS and chronic cerebellar ataxia. They may play a significant role in the disability suffered by these patients.

Adolescent↗
PubMed2001

Detection of optic nerve atrophy following a single episode of unilateral optic neuritis by MRI using a fat-saturated short-echo fast FLAIR sequence.

We describe an MRI technique for quantifying optic nerve atrophy resulting from a single episode of unilateral optic neuritis. We imaged 17 patients, with a median time since onset of optic neuritis of 21 months (range 3-81 months), using a coronal-oblique fat-saturated short-echo fast fluid-attenuated inversion-recovery (sTE fFLAIR) sequence. The mean cross-sectional area of the intraorbital portion of the optic nerves was calculated by a blinded observer from five consecutive 3 mm slices from the orbital apex forwards using a semiautomated contouring technique and compared with data from 16 controls. The mean optic nerve area was 11.2 mm2 in the affected eye of the patients, 12.9 mm2 in the contralateral eye (P = 0.006 compared to the affected eye) and 12.8 mm2 in controls (P = 0.03 compared to the affected eyes). There was a significant negative correlation between disease duration and the size of the affected optic nerve (r = -0.59, P = 0.012). The measurement coefficient of variation was 4.8%. The sTE fFLAIR sequence enables measurement of optic nerve area with sufficient reproducibility to show optic nerve atrophy following a single episode of unilateral optic neuritis. The correlation of increasing optic nerve atrophy with disease duration would be consistent with ongoing axonal loss in a persistently demyelinated lesion, or Wallerian degeneration following axonal damage during the acute inflammatory phase.

Adult↗
PubMed2001

No association between multiple sclerosis and the Notch3 gene responsible for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

The clinical and radiological overlap between multiple sclerosis and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL; MIM 125310) raises the possibility of diagnostic confusion and suggests that pleiotropic effects of the Notch3 gene might include influencing susceptibility to multiple sclerosis. To investigate these possibilities three microsatellites markers closely flanking the Notch 3 gene in 745 simplex families with multiple sclerosis were genotyped and exon 3 and exon 4 of the gene were directly sequenced in a subset of the index members from these families (n=93). No evidence for association was found in any of the three markers and none of the commoner mutations causing CADASIL were found in the sequenced patients.

Adult↗
PubMed2001

Remyelination of demyelinated CNS axons by transplanted human schwann cells: the deleterious effect of contaminating fibroblasts.

Areas of demyelination can be remyelinated by transplanting myelin-forming cells. Schwann cells are the naturally remyelinating cells of the peripheral nervous system and have a number of features that may make them attractive for cell implantation therapies in multiple sclerosis, in which spontaneous but limited Schwann cell remyelination has been well documented. Schwann cells can be expanded in vitro, potentially affording the opportunity of autologous transplantation; and they might also be spared the demyelinating process in multiple sclerosis. Although rat, cat, and monkey Schwann cells have been transplanted into rodent demyelinating lesions, the behavior of transplanted human Schwann cells has not been evaluated. In this study we examined the consequences of injecting human Schwann cells into areas of acute demyelination in the spinal cords of adult rats. We found that transplants containing significant fibroblast contamination resulted in deposition of large amounts of collagen and extensive axonal degeneration. However, Schwann cell preparations that had been purified by positive immunoselection using antibodies to human low-affinity nerve growth factor receptor containing less than 10% fibroblasts were associated with remyelination. This result indicates that fibroblast contamination of human Schwann cells represents a greater problem than would have been appreciated from previous studies.

Animals↗
PubMed2000

Normal polyclonal immunoglobulins ('IVIg') inhibit microglial phagocytosis in vitro.

Phagocytosis removes pathogens and tissue debris during inflammatory reactions, but also plays an important role in autoimmune reactions. The main phagocytes in the central nervous system (CNS) are microglial cells that are activated during CNS inflammation. In the treatment of inflammatory demyelinating diseases like multiple sclerosis (MS), administration of intravenous immunoglobulins (IVIg) has become a promising immunomodulatory therapy. Although a large number of potential mechanisms for the effects of IVIg has been suggested, the precise mode of action in CNS inflammation is unknown. We assessed the influence of IVIg on phagocytosis and endocytosis in microglia in vitro. IVIg had little effect on non-specific phagocytosis of latex particles in untreated microglia, while there was a dose-dependent inhibition in microglia activated with LPS and IFNgamma. Endocytosis of soluble myelin basic protein (MBP) was downregulated by IVIg in both untreated and activated microglia. The effect was mediated by an F(ab')(2) preparation of immunoglobulins, suggesting that Fc receptor-mediated phagocytosis is not involved. Intact IVIg, but not F(ab')(2) fragments also suppressed Fc receptor-mediated phagocytosis of opsonised erythrocytes in both untreated and activated microglia. These results show that IVIg can inhibit the phagocytic activity of microglia via different mechanisms. Such an effect could contribute to the immunomodulatory capacity of IVIg in inflammatory CNS diseases.

Animals↗
PubMed2000

Autoimmune disease in first-degree relatives of patients with multiple sclerosis. A UK survey.

Previous studies examining an association with other autoimmune diseases have suggested the existence of a generalized autoimmune diathesis in patients with multiple sclerosis. We investigated the prevalence of autoimmune disease in first-degree relatives of probands with multiple sclerosis using a case-control method. The results show an excess of autoimmune disease within these families, but no significant association was seen with non-autoimmune diseases. The higher risk in multiplex than simplex families suggests an effect of genetic loading. While the increase in risk applies to each autoimmune disease, autoimmune thyroid disease (and Graves' disease in particular) contributes disproportionately to the excess risk. There was no increase in autoimmune disease within patients with multiple sclerosis themselves when compared with the index controls or population data. We conclude that autoimmune disease is more common in first-degree relatives of patients with multiple sclerosis and hypothesize that common genetic susceptibility factors for autoimmunity co-exist with additional disease specific genetic or environmental factors, which determine clinical phenotype in the individual.

Adolescent↗
PubMed2000

Multiple sclerosis and tonsillectomy: no evidence for an influence on the development of disease or clinical phenotype.

The notion that cervical lymphatic surgery may influence the development of multiple sclerosis has been suggested before. Recent work in experimental allergic encephalomyelitis lends further support to this idea. We, therefore conducted a case:control study of tonsillectomy in multiple sclerosis. We found no evidence to suggest that tonsillectomy affects susceptibility to multiple sclerosis. This result supports previous studies, which have largely failed to show any link between prior tonsillectomy and the subsequent development of multiple sclerosis. In addition, we failed to show any effect of tonsillectomy on the extent of cerebral demyelination as assessed clinically or with magnetic resonance imaging.

Adenoidectomy↗
PubMed1999

Quantitative MRI in patients with secondary progressive MS treated with monoclonal antibody Campath 1H.

BACKGROUND: To assess the long-term effect of the lymphocyte-depleting humanized monoclonal antibody Campath 1H on MR markers of disease activity and progression in secondary progressive MS patients. METHODS: Twenty-five patients participated in a crossover treatment trial with monthly run-in MR scans for 3 months, followed (after a single pulse of Campath 1H) by monthly MR scans from months 1 to 6 and again from months 12 to 18. MR analysis was performed to provide measurements of the number and volume of gadolinium (Gd)-enhancing lesions as well as the hypointense lesion volume on a T1-weighted sequence. In addition, serial measurements of T2 brain lesion volume, brain volume, and spinal cord cross-sectional area were made over the duration of the study. The relationship between clinical and MR measures of disease evolution was also assessed. RESULTS: Treatment was associated with a reduction in the number and volume of Gd-enhancing lesions (p < 0.01). Despite this, a decrease in brain volume was seen in 13 patients during the 18 months post-treatment. The mean pretreatment Gd-enhancing lesion volume was predictive of subsequent reduction in brain volume (r = 0.77, p = 0.002). Reduction in brain volume also correlated with the change in T1 hypointense lesion volume after treatment (r = 0.53, p < 0.01). A reduction in spinal cord area was also seen throughout the study duration, and this correlated with an increase in disability (r = 0.65, p = 0.01). CONCLUSION: Campath 1H treatment was associated with a sustained and marked reduction in the volume of Gd enhancement, indicating suppression of active inflammation. Nevertheless, many patients developed increasing brain and spinal cord atrophy, T1 hypointensity, and disability. This study highlights the potential role for novel MR techniques in monitoring the effect of treatment on the pathologic process in MS.

Adult↗
PubMed1999

Recall antigen presentation by gamma-interferon-activated microglia results in T cell activation and propagation of the immune response.

The interaction between microglia and T cells is important in the development of central nervous system inflammation. This may result in full T cell activation, a partial state of activation, anergy or apoptosis of the 'responding' T cell. Here, we demonstrate that neonatal rodent microglia not only fail to initiate a mixed lymphocyte reaction (MLR), but suppress background T cell proliferation. Even after activation with gamma-IFN or following phagocytosis, microglia remain unable to support a MLR. By contrast, gamma-IFN-activated microglia are able to activate memory T cells in a recall assay resulting in cytokine (gamma-IFN) release and modest T cell proliferation. Although the stimulation index is small, functional relevance is demonstrated. Supernatants from the recall assay stimulate gamma-IFN-dependent activation of a STAT (signal transducer and activator of transcription) factor within resting microglia. This demonstrates that memory T cells not only receive sufficient stimulation from the gamma-IFN-activated microglia to proliferate and produce cytokines, but that there is also a reciprocal stimulation of resting microglia. Importantly, this provides evidence that activated microglia have the potential to propagate immune responses in the central nervous system, but are unlikely to initiate a primary response.

Animals↗
PubMed1999

Comparison of C1q-receptors on rat microglia and peritoneal macrophages.

A comparison of the expression and ligand specificity of the C1q (first complement component) receptor on rat microglia and peritoneal macrophages was made. This revealed that radiolabelled C1q was competed from the peritoneal macrophages with intact C1q, and additively displaced by calf-skin collagen and purified C1q globular heads, suggesting the presence of at least two receptors. This was in contrast to microglia, where radiolabelled C1q was displaced with intact C1q and to a modest degree with collagen, but not with globular heads. Taken together, this implies that under these conditions, peritoneal macrophages and microglia both express a C1q receptor which binds to the collagen-like region, and that peritoneal macrophages additionally express a molecule which binds to the globular head of C1q. Analysis of the ligand bound by these cells reflected the differences observed in the competitive binding experiments, with the novel identification of naturally-occurring peptides from the globular head of C1q bound to the peritoneal macrophages, but not the microglia.

Amino Acid Sequence↗
PubMed1999

Urinary, faecal and sexual dysfunction in patients with multiple sclerosis.

The prevalence and nature of bladder and bowel dysfunction were examined in a population-based study of 221 patients with multiple sclerosis who returned postal questionnaires. This preliminary investigation was supplemented by personal review which also provided information on sexual dysfunction in 174 and laboratory and urodynamic tests in 152 participants. Thirty of 221 (14%) currently used an indwelling catheter, and 84 of the remaining 190 (44%) reported symptoms of urinary dysfunction, of which the most common were urgency and frequency. Thirteen of 144 (9%) patients had biochemical evidence of renal dysfunction, and 40 of 132 (30%) had infected urine samples. Eleven of 54 patients in whom investigation of upper urinary tract was thought to be appropriate demonstrated abnormalities. Sixty-four of 221 (29%) patients had experienced faecal incontinence, and 120 of 221 (54%) were constipated. Fifty-six of 68 (82%) men and 55 of 106 (52%) women reported a deterioration in sexual activity, the commonest symptoms being erectile failure in men and fatigue in women.

Constipation↗
PubMed1999

Identification of A2B5-positive putative oligodendrocyte progenitor cells and A2B5-positive astrocytes in adult human white matter.

Spontaneous remyelination of previously demyelinated axons is found in a substantial minority of acute and chronic lesions in multiple sclerosis. In the rodent, central remyelination restores saltatory conduction and helps restore limb function, and it seems likely that endogenous myelin repair contributes to neurological recovery in multiple sclerosis. However, the identity of the remyelinating cell remains enigmatic. Fully differentiated oligodendrocytes have very limited capacity for recapitulating their developmental activities and re-engaging myelination pathways. Proliferative oligodendrocyte progenitors--often known as O-2A cells because of their ability to differentiate in vitro into either oligodendrocytes or ("type 2") astrocytes--are, in contrast, extremely efficient at myelin repair either spontaneously, or after transplantation into the de- or dysmyelinated CNS. Oligodendrocyte progenitors are present in both developing and adult rodent CNS. We have previously demonstrated that proliferative oligodendrocyte progenitors are present in cultures prepared from the adult human CNS. Here, using fresh tissue print preparations, we report that cells with processes and the A2B5-positive immunophenotype of proliferative oligodendrocyte progenitors are present in situ in adult human white matter. This technique also reveals the occurrence of A2B5-positive astrocytes, a cell also not previously identified in the normal adult human CNS. In the light of the rodent data showing the importance of oligodendrocyte progenitors in myelin repair, our findings suggesting the presence of progenitors in the adult human brain may have significant implications for spontaneous remyelination in multiple sclerosis and other demyelinating conditions.

Adult↗
PubMed1998

HLA associations with multiple sclerosis in the Canary Islands.

The study of small island populations has proved informative with respect to the epidemiology and genetics of many complex traits including multiple sclerosis. The class II major histocompatibility antigen DR15 is associated with multiple sclerosis in all groups except Sardinians, where the primary association is with DR4. We compared HLA-DR and -DQ allele frequencies in a representative sample of patients with multiple sclerosis from the Canary Islands with appropriate controls. There was a significant association with DR15 (patients 21/53: 40%: controls 11/55; 20%: chi2=4.09; pc=0.04; relative risk [RR]=1.98). DRB1*1501-DRB5*0101 was present in 17/53 (32%) patients in whom sub-types could be identified compared with 6/55 (11%) controls (chi2=7.21; pc=< 0.01; RR=2.94). All DR15 positive controls carried the DQA1*0102, DQB1*0602 haplotype whereas this was only present in 26/30 patients, suggesting that the primary association is with HLA-DR and not -DQ. We also found a significant increase in HLA-DR4 (16/53 [30%] in patients compared with 7/55 [13%] in controls; pc=0.05). This study contributes a new point on the immunogenetic map of multiple sclerosis in Europe, confirming the primary DR15 association with multiple sclerosis in a previously unstudied population but again highlighting the importance of DR4 in Mediterranean peoples.

Alleles↗
PubMed1998

Interferon-beta inhibits mitogen induced astrocyte proliferation in vitro.

The central nervous system response to injury and inflammation commonly includes astrocytosis. This process, which is manifest by astrocyte hypertrophy and proliferation, is particularly prominent in multiple sclerosis (MS), where in chronic lesions it may contribute to the lack of repair by restricting the migration of remyelinating cells. Interferon-beta (IFN-beta) modestly reduces the frequency of relapses in MS and may have a small effect on the accumulation of permanent disability. Here, we show that IFN-beta inhibits the in vitro proliferative response of rodent astrocytes to a wide variety of growth factors and cytokines. Although important species differences exist in these glial responses this previously unrecognised property of IFN-beta may have implications for reducing astrocytosis and thereby promoting endogenous repair.

Animals↗
PubMed1998

The expression of complement regulatory proteins by adult human oligodendrocytes.

In multiple sclerosis, infiltrating T lymphocytes and perivascular microglia may initiate demyelinating lesions, but a role for antibody and complement in the ensuing inflammatory damage to myelin and oligodendrocytes is likely. In most tissues, ubiquitously expressed complement regulatory proteins prevent autologous destruction, protecting host cells from the powerful cytolytic activity of activated complement. We have studied the surface expression of a comprehensive range of complement regulatory proteins by live adult human oligodendrocytes in vitro. Only DAF of the activation pathway regulators was expressed, not CR1 or MCP. Of the membrane attack pathway regulatory proteins, HRF was not expressed, while substantial heterogeneity of CD59 expression by oligodendrocytes was found. Clusterin expression was not found. A relative deficiency of protective complement regulatory proteins on human oligodendrocytes may contribute to their selective damage in multiple sclerosis.

CD59 Antigens↗