I nterferon beta-1a slows progression of brain atrophy in relapsing-remitting multiple sclerosis predominantly by reducing gray matter atrophy

High-dose, high-frequency recombinant interferon beta-1a in the treatment of multiple sclerosis

BACKGROUND

There is at present no cure for multiple sclerosis (MS), and existing therapies are designed primarily to prevent lesion formation, decrease the rate and severity of relapses and delay the resulting disability by reducing levels of inflammation.

OBJECTIVE

The aim of this review was to assess the treatment of relapsing MS with particular focus on subcutaneous (s.c.) interferon (IFN) beta-1a.

METHOD

The literature on IFN beta-1a therapy of MS was reviewed based on a PubMed search (English-language publications from 1990) including its pharmacodynamics and pharmacokinetics, clinical efficacy in relapsing MS as shown in placebo-controlled studies and in comparative trials, efficacy in secondary progressive MS, safety and tolerability, and the impact of neutralizing antibodies.

CONCLUSION

The literature suggests that high-dose, high-frequency s.c. IFN beta-1a offers an effective option for treating patients with relapsing MS, with proven long-term safety and tolerability, and has a favourable benefit-to-risk ratio compared with other forms of IFN beta.

Gray matter pathology in (chronic) MS: modern views on an early observation

Involvement of the gray matter (GM) in the pathology of multiple sclerosis (MS) was already recognized in the early days of MS research, but the detection of (cortical) GM lesions under the microscope and with magnetic resonance imaging (MRI) techniques was initially suboptimal and could only recently be enhanced. The visualization of GM lesions in vivo opens new doors for studies focusing on clinical, especially cognitive, effects of GM pathology, as well as for monitoring of neuroprotective treatment. However, so far little is known about what causes GM pathology. In this review, several pathogenetic mechanisms will be discussed, affecting the MS brain both from the 'outside-in' and from the 'inside-out'. Also, the use and reliability of MRI atrophy measures as a monitoring tool for GM damage in the therapeutic setting will be reviewed.

Gray matter atrophy is related to long-term disability in multiple sclerosis

OBJECTIVE

To determine the relation of gray matter (GM) and white matter (WM) brain volumes, and WM lesion load, with clinical outcomes 20 years after first presentation with clinically isolated syndrome suggestive of multiple sclerosis (MS).

METHODS

Seventy-three patients were studied a mean of 20 years from first presentation with a clinically isolated syndrome (33 of whom developed relapsing-remitting MS and 11 secondary-progressive MS, with the rest experiencing no further definite neurological events), together with 25 healthy control subjects. GM and WM volumetric measures were obtained from three-dimensional T1-weighted brain magnetic resonance images using Statistical Parametric Mapping 2.

RESULTS

Significant GM (p < 0.001) and WM atrophy (p = 0.001) was seen in MS patients compared with control subjects. There was significantly more GM, but not WM atrophy, in secondary-progressive MS versus relapsing-remitting MS (p = 0.003), and relapsing-remitting MS versus clinically isolated syndrome (p < 0.001). GM, but not WM, fraction correlated with expanded disability status scale (r(s) = -0.48; p < 0.001) and MS Functional Composite scores (r(s) = 0.59; p < 0.001). WM lesion load correlated with GM (r(s) = -0.63; p < 0.001), but not with WM fraction. Regression modeling indicated that the GM fraction explained more of the variability in clinical measures than did WM lesion load.

INTERPRETATION

In MS patients with a relatively long and homogeneous disease duration, GM atrophy is more marked than WM atrophy, and reflects disease subtype and disability to a greater extent than WM atrophy or lesions.

Interferon-beta treatment for relapsing multiple sclerosis

BACKGROUND

Recombinant forms of IFN-beta were the first therapeutic intervention found to be effective at interfering with the course of multiple sclerosis (MS), a chronic and debilitating disease affecting the CNS in young adults.

OBJECTIVE/METHODS

To examine the application of IFN-beta to MS treatment by a review of relevant literature.

RESULTS

The different IFN-beta products available are similar in their clinical effects. However, the response to IFN-beta therapy is only partial and the most efficient individual-specific dose, route and frequency of administration are not elucidated fully. The mechanism of action of IFN-beta in MS is also not understood fully but its immunomodulatory effects are probably more important than its anti-proliferative and antiviral activities.

CONCLUSIONS

Although new therapeutic approaches are being sought to better treat MS, IFN-beta remains one of the most recognized and approved worldwide therapeutic options for this disease.

New treatment measurements for treatment effects on relapses and progression

Multiple sclerosis (MS) is considered to be a two stage disease: a first stage in which inflammatory phenomena are crucial and a later one in which degenerative processes become the hallmark. The role of magnetic resonance imaging (MRI) is nowadays of great help both to establish the diagnosis and to rule out other conditions. At the clinically isolated syndrome (CIS) stage, MRI is an important tool both to predict the appearance of a second attack or the development of disability at long term. In the relapsing-remitting (RR) phase of the disease conventional MRI is probably less helpful to predict future relapses and disability. Cross sectional and longitudinal studies have shown very weak correlations between lesion burden on brain T2 and disability in the progressive forms of MS. Regarding T2 burden of disease, a plateau effect for EDSS values greater than 4.5 has been observed. Measures related to brain or spinal cord atrophy together with MR Spectroscopy, Magnetization Transfer Imaging and Diffusion Tensor Imaging may be useful in the future to better monitor disease progression in the late degenerative phase of the condition. MRI has also been of great help in monitoring the effect of immunomodulatory drugs in CIS or RRMS clinical trials. Its role to predict treatment response is still controversial on an individual basis.

Magnetic resonance imaging measures of brain and spinal cord atrophy correlate with clinical impairment in secondary progressive multiple sclerosis

BACKGROUND

Neuroaxonal loss is a pathological substrate of disability in progressive multiple sclerosis (MS) and can be estimated in vivo by measuring tissue atrophy on magnetic resonance imaging (MRI). While there is some evidence that brain atrophy correlates better with disability than T2 lesion load in secondary progressive MS, the clinical relevance of atrophy within specific regions of the central nervous system requires further evaluation.

METHODS

Clinical and MRI examinations were performed in 117 subjects with secondary progressive MS. MRI analysis included measures of normalized brain volume (NBV), normalized grey matter (NGMV) and white matter volume (NWMV), central cerebral volume (CCV), spinal cord cross-sectional area (SCCA), and brain T2 and T1 lesion volume. Clinical assessments included the expanded disability status scale (EDSS) and MS functional composite (MSFC).

RESULTS

All MRI measures correlated significantly with the MSFC score, with the strongest correlation being for the NBV (r = 0.47; P < 0.001). NBV and SCCA were the only significant independent predictors of the MSFC score in a stepwise regression model containing all the MRI measures, and SCCA was the only MRI measure to show a significant association with the EDSS. While NGMV had stronger correlations with the clinical variables than NWMV, NBV was more correlated with clinical impairment than either measure.

CONCLUSIONS

This data suggests that measures of atrophy, particularly of the whole brain and spinal cord, are relevant and useful disease markers in secondary progressive MS.

MRI in multiple sclerosis: what's inside the toolbox?

Magnetic resonance imaging (MRI) has played a central role in the diagnosis and management of multiple sclerosis (MS). In addition, MRI metrics have become key supportive outcome measures to explore drug efficacy in clinical trials. Conventional MRI measures have contributed to the understanding of MS pathophysiology at the macroscopic level yet have failed to provide a complete picture of underlying MS pathology. They also show relatively weak relationships to clinical status such as predictive strength for clinical progression. Advanced quantitative MRI measures such as magnetization transfer, spectroscopy, diffusion imaging, and relaxometry techniques are somewhat more specific and sensitive for underlying pathology. These measures are particularly useful in revealing diffuse damage in cerebral white and gray matter and therefore may help resolve the dissociation between clinical and conventional MRI findings. In this article, we provide an overview of the array of tools available with brain and spinal cord MRI technology as it is applied to MS. We review the most recent data regarding the role of conventional and advanced MRI techniques in the assessment of MS. We focus on the most relevant pathologic and clinical correlation studies relevant to these measures.

Preservation of gray matter volume in multiple sclerosis patients with the Met allele of the rs6265 (Val66Met) SNP of brain-derived neurotrophic factor

To investigate the association of the rs6265 (Val66Met) single nucleotide polymorphism (SNP) of brain-derived neurotrophic factor (BDNF) with brain morphometry and functional status as measured by quantitative magnetic resonance imaging (MRI) and neurocognitive testing in multiple sclerosis (MS) patients. BDNF is released by neurons and by immune cells in MS brain. The rs6265 SNP variation of BDNF causes substitution of valine (Val) for methionine (Met) and interferes with activity-dependent BDNF secretion. A total of 209 treated MS patients (161 females; 48 males) underwent clinical brain MRI and were genotyped for the BDNF rs6265 Val66Met SNP. A subset of 108 patients had neurocognitive testing for processing speed, memory and executive function. The MRI measurements included T2 and T1-lesion volume (LV); normalized brain volume measures of whole brain (WB) volume, white and gray matter volume (NWMV and NGMV) and the diffusion-weighted imaging measure of WB mean parenchyma diffusivity (MPD). The Met66 allele status was positively associated with NGMV (P = 0.015, standardized beta = 0.15) and negatively associated with T2-LV (P = 0.041, standardized beta = -0.14). There were no significant associations between Met66 allele status and T1-LV, NWMV or MPD. On the Paced Serial Addition Test (PASAT), a trend (P = 0.057) favoring the Met66 allele group was observed. There were no significant associations between Met66 allele status and other neurocognitive measures. The BDNF Met66 allele is associated with lower damage as evidenced by measurement of NGMV and T2-LV in MS patients.

Neuroimaging in multiple sclerosis

Conventional magnetic resonance imaging (MRI) has routinely been used to improve the accuracy of multiple sclerosis (MS) diagnosis and prognosis. Metrics derived from conventional MRI are now routinely used to detect therapeutic effects and extend clinical observations. However, conventional MRI measures, such as the use of lesion volume and count of gadolinium-enhancing and T2 lesions, have insufficient sensitivity and specificity to reveal the true degree of pathological changes occurring in MS. They cannot distinguish between inflammation, edema, demyelination, Wallerian degeneration, and axonal loss. In addition, they do not show a reliable correlation with clinical measures of disability and do not provide a complete assessment of therapeutic outcomes. Recent neuropathologic studies of typical chronic MS brains reveal macroscopic demyelination in cortical and deep gray matter (GM) that cannot be detected by currently available MRI techniques. Therefore, there is a pressing need for the development of newer MRI techniques to detect these lesions. Newer metrics of MRI analysis, including T1-weighted hypointense lesions, central nervous system atrophy measures, magnetization transfer imaging, magnetic resonance spectroscopy, and diffusion tensor imaging, are able to capture a more global picture of the range of tissue alterations caused by inflammation and neurodegeneration. At this time, they provide the only proof--albeit indirect--that important occult pathology is occurring in the GM. However, evidence is increasing that these nonconventional MRI measures correlate better with both existing and developing neurological impairment and disability when compared to conventional metrics.