Biomedical subjects

Yves Lapierre

Publications and source records attributed to Yves Lapierre.

8 recordsLinked to original sources

PubMed2006

Potential for interferon beta-induced serum antibodies in multiple sclerosis to inhibit endogenous interferon-regulated chemokine/cytokine responses within the central nervous system.

BACKGROUND: A proportion of patients with multiple sclerosis (MS) receiving systemic interferon beta therapy will develop serum neutralizing antibodies (NAbs) that can reduce the activity of the drug. Interferon-beta (IFN-beta) is produced by glial cells within the central nervous system. Although systemic interferon beta does not access the central nervous system, titers of serum NAbs may be sufficient that some will access the central nervous system. OBJECTIVE: To address whether serum samples that contain high titers of NAbs could inhibit glial cell production of chemokines and cytokines that are regulated by endogenous IFN-beta. DESIGN: We used an in vitro assay involving toll-like receptor 3 ligand (polyinosinic-polycytidylic acid) signaling to assess the effect of serum samples containing high titers of NAbs (1800-20 000 U) on production of the chemokine CXCL10 and the cytokine interleukin 6 by human astrocytes. RESULTS: Serum samples positive for NAbs significantly inhibited polyinosinic-polycytidylic acid-induced CXCL10 and IL-6 production by astrocytes. CONCLUSION: High-titer NAbs to interferon beta may block endogenous IFN-beta function and alter the chemokine/cytokine microenvironment within the central nervous system, thereby modulating the profile and course of the local inflammatory response.

Adult↗

PubMed2005

Axonal injury in the cerebral normal-appearing white matter of patients with multiple sclerosis is related to concurrent demyelination in lesions but not to concurrent demyelination in normal-appearing white matter.

We assessed axonal injury and demyelination in the cerebral normal-appearing white matter (NAWM) of MS patients in a pilot study using proton magnetic resonance spectroscopic imaging and quantitative magnetization transfer (MT) imaging. Resonance intensities of N-acetylaspartate (NAA) relative to creatine (Cr) were measured in a large central brain volume. NAA/Cr in NAWM was estimated by regression of the NAA/Cr in each voxel against white matter fraction and extrapolation to a white matter fraction of 1. The fractional size of the semi-solid pool (F) was obtained from the binary spin bath model of MT by computing the model parameters from multiple MT-weighted and relaxometry acquisitions. F in NAWM was significantly smaller in the patients [0.109 (0.009)] relative to controls [0.123 (0.007), P = 0.011], but did not differ between RR [0.1085] and SP [0.1087] patients [P > 0.99]. NAA/Cr and F in the NAWM were not correlated (r = 0.16, P > 0.7), mainly due to a lack of variation in F among patients. This may indicate a floor to the extent of myelin pathology that can occur in NAWM before a lesion appears, or that axonal damage is not strictly related to demyelination. The correlation between NAWM NAA/Cr and T2w lesion volume was not significant (P > 0.1). However, dividing the lesion volumes by the mean F in T2w lesions resulted in a quantity that correlated well with NAWM NAA/Cr (r = -0.78, P = 0.038), possibly reflecting the association of Wallerian degeneration in the NAWM with axonal transection associated with demyelination within lesions.

Adult↗

PubMed2005

Neuromyelitis optica with hypothalamic involvement.

We describe two cases of neuromyelitis optica (NMO) with clinical and radiographically confirmed features of hypothalamic involvement, in the absence of other parenchymal brain lesions. Their course is otherwise typical of Devic's form of NMO. A review of the literature identifies additional cases of NMO in which clinical features attributable to under-recognized dysfunction of the hypothalamic-pituitary axis were present. We propose that the currently accepted criteria for the diagnosis of NMO could be revisited to recognize the possibility of lesions developing within hypothalamic structures.

Adolescent↗

PubMed2004

Type 2 monocyte and microglia differentiation mediated by glatiramer acetate therapy in patients with multiple sclerosis.

Glatiramer acetate (GA) therapy of patients with multiple sclerosis (MS) represents a unique setting in which in vivo Th2 deviation of T cells is consistently observed and associated with clinical benefit in a human autoimmune disease. We postulated that APCs are important targets of GA therapy and demonstrate that treatment of MS patients with GA reciprocally regulates the IL-10/IL-12 cytokine network of monocytes in vivo. We further show that Th1- or Th2-polarized GA-reactive T cells isolated from untreated or treated MS patients mediate type 1 and 2 APC differentiation of human monocytes, based on their ability to efficiently induce subsequent Th1 and Th2 deviation of naive T cells, respectively. These observations are extended to human microglia, providing the first demonstration of type 2 differentiation of CNS-derived APCs. Finally, we confirm that the fundamental capacity of polarized T cells to reciprocally modulate APC function is not restricted to GA-reactive T cells, thereby defining a novel and dynamic positive feedback loop between human T cell and APC responses. In the context of MS, we propose that GA therapy results in the generation of type 2 APCs, contributing to Th2 deviation both in the periphery and in the CNS of MS patients. In addition to extending insights into the therapeutic mode of action of GA, our findings revisit the concept of bystander suppression and underscore the potential of APCs as attractive targets for therapeutic immune modulation.

Adult↗

PubMed2004

The relationship between diffuse axonal damage and fatigue in multiple sclerosis.

BACKGROUND: Fatigue is a common and distressing symptom for patients with multiple sclerosis (MS). There is growing evidence that fatigue in MS has a central nervous system component. We hypothesized that diffuse cerebral axonal damage could be associated with fatigue and used proton magnetic resonance spectroscopy to noninvasively measure axonal damage or loss in the brains of patients with MS. OBJECTIVE: To assess the strength of the relationship between central brain N-acetylaspartate and fatigue. DESIGN: Data from 73 patients who had undergone proton magnetic resonance spectroscopy imaging and completed the Fatigue Severity Scale questionnaire were analyzed. RESULTS: The N-acetylaspartate-creatine ratio (NAA/Cr) was significantly lower in the high-fatigue group than the low-fatigue group (mean +/- SD, 2.69 +/- 0.29 and 2.99 +/- 0.33, respectively. P =.003). Independent of the Kurtzke Expanded Disability Status Scale, T2 lesion volume, age, and disease duration, NAA/Cr was significantly lower in the high-fatigue group as compared with the low-fatigue group. There was a statistically significant linear correlation between the Fatigue Severity Scale scores and NAA/Cr (Spearman rank rho = -0.361, P =.02). CONCLUSIONS: The results of this study, combined with those of others, suggest that widespread axonal dysfunction is associated with fatigue in MS. Increased recruitment of cortical areas and pathways in response to brain injury may be responsible for the patient's sense that the effort required to perform actions is disproportionately high.

Adult↗

PubMed2004

Do general and multiple sclerosis-specific quality of life instruments differ?

BACKGROUND: Quality of life instruments provide information that traditional outcome measures used in studies of multiple sclerosis do not. It is unclear if longer, disease-specific instruments provide more useful information than shorter, more general instruments, or whether patients prefer one type to another. METHODS: We conducted a cross-sectional study of quality of life in a multiple sclerosis clinic population using a mailed questionnaire that combined three different quality of life instruments; the SF-36, the Multiple Sclerosis Quality of Life Instrument-54, and the EuroQol EQ-5D. We assessed the feasability of using each instrument and patient preference for each, calculated correlation coefficients for the summary scores of each instrument and other measures of disease severity, and calculated odds ratios from proportional odds models comparing each instrument with the Expanded Disability Status Scale. RESULTS: We did not find substantial differences between the three instruments. All were well-received by patients, and over 75% felt that the combination of the three instruments best assessed their quality of life. For each instrument there was substantial variability between patients with similar quality of life scores in terms of their disability (as assessed by the Expanded Disability Status Scale and their own perception of their disease severity and quality of life (on simple 1-10 scales). CONCLUSIONS: Quality of life instruments are easy to use and well-received by patients, regardless of their length. There do not appear to be clinically important differences between general and disease-specific instruments. Each instrument appears to measure something other than a patient's disability or perception of their own disease severity or quality of life.

Adult↗

PubMed2004

Axonal damage in multiple sclerosis patients with high versus low expanded disability status scale score.

BACKGROUND: The pathophysiological basis for differences in disability in patients with multiple sclerosis is unclear. METHODS: We used magnetic resonance imaging to examine whether differences in disability in cohorts of multiple sclerosis patients with similar T2-weighted lesion volume and disease duration were associated with a more destructive disease process in the more disabled patients. RESULTS: The benign and severely disabled groups had similar brain atrophy metrics and similar decreases of the neuronal marker, N-acetylaspartate, in the normal appearing white matter of the cerebrum on magnetic resonance spectroscopy examination in vivo. The severely disabled cohort had more spinal cord atrophy. CONCLUSION: The dissociation of spinal cord atrophy and cerebral atrophy between these two groups suggests that the difference between the more benign and more disabled groups cannot be explained by a more aggressive pathological process that is affecting the entire neuroaxis in a homogeneous fashion.

Adult↗

PubMed2003

Multiple sclerosis vs acute disseminated encephalomyelitis in childhood.

The initial presenting clinical and laboratory findings of either acute disseminated encephalomyelitis or the first attack of multiple sclerosis in the pediatric population were compared and contrasted. A retrospective review of the medical records was conducted of all children younger than 17 years who presented with either the diagnosis of acute disseminated encephalomyelitis or multiple sclerosis between 1987 and 2001. Seventeen cases of clinically definite multiple sclerosis (seven female, mean age 12.4 +/- 4.5 years) and seven cases of acute disseminated encephalomyelitis (three female; mean age 8.7 +/- 3.8 years) were reviewed. Systemic and nonfocal neurologic symptoms were more commonly evident in acute disseminated encephalomyelitis than in multiple sclerosis: fever (43% vs 6%), headache (57% vs 24%), fatigue (71% vs 29%), vomiting (57% vs 0%), and encephalopathy (71% vs 6%). In multiple sclerosis patients, T(2)-weighted white matter magnetic resonance imaging lesions were more commonly located in the corpus callosum (64% vs 17%) and the periventricular area (91% vs 50%) compared with those in patients with acute disseminated encephalomyelitis. These results suggest that acute disseminated encephalomyelitis and multiple sclerosis can be differentiated to some degree according to clinical and radiologic data at initial presentation, which is important because the long-term prognosis for childhood multiple sclerosis appears to be less favorable.

Adolescent↗