Blood-CSF barrier integrity in multiple sclerosis

Intrathecal immune reactivity against Measles-, Rubella-, and Varicella Zoster viruses is associated with cerebrospinal fluid inflammation in multiple sclerosis

BACKGROUND/OBJECTIVES

We aimed to determine in multiple sclerosis (MS) whether intrathecal immunoglobulin G (IgG) production against measles- (M), rubella- (R), and varicella zoster (Z) viruses, which is called MRZ reaction (MRZR) and considered the most specific soluble biomarker for MS, is associated with demographic and basic cerebrospinal fluid (CSF) parameters reflecting inflammation.

METHODS

We analyzed the presence of positive MRZR and associations with demographic and clinical routine CSF parameters in 513 patients with MS and 182 non-MS patients.

RESULTS

Comparing MS patients versus non-MS patients, positive MRZR (38.8% versus 2.2%; specificity 97.8%; positive likelihood ratio, PLR 17.7) had a better specificity and PLR for MS than CSF-specific OCB (89.5% versus 22.0%; specificity 78.0%; PLR 4.1). A positive MRZR in MS patients was associated with female sex (p = 0.0001), pleocytosis (p < 0.0001), higher frequency of presence of plasma cells in CSF (p = 0.0248), normal CSF/serum albumin ratio (p = 0.0005), and intrathecal production of total IgG or CSF-specific OCB (both p < 0.0001), but not with intrathecal production of total IgA or IgM.

CONCLUSIONS

This study confirms the MRZR as a highly specific marker of MS and shows that MRZR-positive MS patients more frequently are female and show inflammatory changes of basic CSF parameters than MRZR-negative MS patients.

Choroid plexus volume as a marker of retinal atrophy in relapsing remitting multiple sclerosis

OBJECTIVE

To evaluate choroid plexus (CP) volume as a biomarker for predicting clinical disability and retinal layer atrophy in relapsing remitting multiple sclerosis (RRMS).

METHODS

Ninety-five RRMS patients and 26 healthy controls (HCs) underwent 3 T whole brain MRI, expanded disability status scale (EDSS) and optical coherence tomography (OCT). Fully automated intra-retinal segmentation was performed to obtain the volumes of the retinal nerve fiber layer (RNFL), combined ganglion cell layer -inner plexiform layer (GCIPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), retinal pigment epithelium (RPE), total macular volume (TMV) and papillomacular bundle (PMB). Automated segmentation of the CP within the lateral ventricles was performed and the choroid plexus volume (CPV) was normalized by total intracranial volume (TIV). Linear regression analysis and generalized estimating equation (GEE) models were applied to evaluate relationships between nCPV and EDSS, T2 lesion volume, disease duration, and retinal layer volumes, followed by Bonferroni correction analysis for multiple comparisons.

RESULTS

RRMS patients had larger tChPV compared to HCs (p < 0.001). After Bonferroni correction, there was a significant positive correlation between tChPV and EDSS (r2 = 0.25, p = 0.0002), disease duration (r2 = 0.30, p = 0.01), and T2 lesion volume (r2 = 0.39, p = 0.0000). A robust negative correlation was found between tChPV and RNFL (p < 0.001), GCIPL (p = 0.003), TMV (p = 0.0185), PMB (p < 0.0001), G (p = 0.04), T(p = 0.0001).

CONCLUSIONS

Our findings support the association of tChPV with disability and altered retinal integrity in RRMS.

Basic CSF parameters and MRZ reaction help in differentiating MOG antibody-associated autoimmune disease versus multiple sclerosis

Background

Myelin oligodendrocyte glycoprotein antibody-associated autoimmune disease (MOGAD) is a rare monophasic or relapsing inflammatory demyelinating disease of the central nervous system (CNS) and can mimic multiple sclerosis (MS). The variable availability of live cell-based MOG-antibody assays and difficulties in interpreting low-positive antibody titers can complicate diagnosis. Literature on cerebrospinal fluid (CSF) profiles in MOGAD versus MS, one of the most common differential diagnoses, is scarce. We here analyzed the value of basic CSF parameters to i) distinguish different clinical MOGAD manifestations and ii) differentiate MOGAD from MS.

Methods

This is retrospective, single-center analysis of clinical and laboratory data of 30 adult MOGAD patients and 189 adult patients with relapsing-remitting multiple sclerosis. Basic CSF parameters included CSF white cell count (WCC) and differentiation, CSF/serum albumin ratio (QAlb), intrathecal production of immunoglobulins, CSF-restricted oligoclonal bands (OCB) and MRZ reaction, defined as intrathecal production of IgG reactive against at least 2 of the 3 viruses measles (M), rubella (R) and varicella zoster virus (Z).

Results

MOGAD patients with myelitis were more likely to have a pleocytosis, a QAlb elevation and a higher WCC than those with optic neuritis, and, after review and combined analysis of our and published cases, they also showed a higher frequency of intrathecal IgM synthesis. Compared to MS, MOGAD patients had significantly more frequently neutrophils in CSF and WCC>30/µl, QAlb>10×10-3, as well as higher mean QAlb values, but significantly less frequently CSF plasma cells and CSF-restricted OCB. A positive MRZ reaction was present in 35.4% of MS patients but absent in all MOGAD patients. Despite these associations, the only CSF parameters with relevant positive likelihood ratios (PLR) indicating MOGAD were QAlb>10×10-3 (PLR 12.60) and absence of CSF-restricted OCB (PLR 14.32), whereas the only relevant negative likelihood ratio (NLR) was absence of positive MRZ reaction (NLR 0.00).

Conclusion

Basic CSF parameters vary considerably in different clinical phenotypes of MOGAD, but QAlb>10×10-3 and absence of CSF-restricted OCB are highly useful to differentiate MOGAD from MS. A positive MRZ reaction is confirmed as the strongest CSF rule-out parameter in MOGAD and could be useful to complement the recently proposed diagnostic criteria.

Cerebrospinal fluid–related tissue damage in multiple sclerosis patients with iron rim lesions

Background:

In multiple sclerosis (MS), iron rim lesions (IRLs) are associated with pronounced tissue damage, higher disease severity and have been suggested as an imaging marker of chronic active inflammation behind the blood–brain barrier indicating progression. Furthermore, chronic intrathecal compartmentalized inflammation has been suggested to be a mediator of a cerebrospinal fluid (CSF)–related tissue damage.

Objective:

To investigate CSF markers of intrathecal inflammation in patients with at least one IRL compared to patients without IRLs and to investigate tissue damage in lesions and normal-appearing white matter (NAWM) with proximity to CSF spaces.

Methods:

A total of 102 patients (51 with at least 1 IRL and 51 age-/sex-matched patients without IRL) scanned with the same 3T magnetic resonance imaging (MRI) and having CSF analysis data were included.

Results:

Patients with at least one IRL had higher disability scores, higher lesion volumes, lower brain volumes and a higher intrathecal immunoglobulin G (IgG) synthesis. Apparent diffusion coefficient (ADC) values in IRLs were higher compared to non-IRLs. We observed a negative linear correlation of ADC values in all tissue classes and distance to CSF, which was stronger in patients with high IgG quotients.

Conclusion:

IRLs are associated with higher intrathecal IgG synthesis. CSF-mediated intrathecal smouldering inflammation could explain a CSF-related gradient of tissue damage.

Blood-cerebrospinal fluid (CSF) barrier dysfunction means reduced CSF flow not barrier leakage - conclusions from CSF protein data

BACKGROUND

Increased concentrations of serum proteins in cerebrospinal fluid (CSF) are interpreted as blood-CSF barrier dysfunction. Frequently used interpretations such as barrier leakage, disruption or breakdown contradict CSF protein data, which suggest a reduced CSF flow rate as the cause.

RESULTS

Even the severest barrier dysfunctions do not change the molecular size-dependent selectivity or the interindividual variation of the protein transfer across barriers. Serum protein concentrations in lumbar CSF increase with hyperbolic functions, but the levels of proteins that do not pass the barrier remain constant (brain proteins) or increase linearly (leptomeningal proteins). All CSF protein dynamics above and below a lumbar blockade can also be explained, independent of their barrier passage, by a reduced caudally directed flow. Local accumulation of gadolinium in multiple sclerosis (MS) is now understood as due to reduced bulk flow elimination by interstitial fluid (ISF). Nonlinear change of the steady state in barrier dysfunction and along normal rostro-caudal gradients supports the diffusion/flow model and contradicts obstructions of diffusion pathways. Regardless of the cause of the disease, pathophysiological flow blockages are found in bacterial meningitis, leukemia, meningeal carcinomatosis, Guillain-Barré syndrome, MS and experimental allergic encephalomyelitis. In humans, the fortyfold higher albumin concentrations in early fetal development decrease later with maturation of the arachnoid villi, i.e., with beginning CSF outflow, which contradicts a relevant outflow to the lymphatic system. Respiration- and heartbeat-dependent oscillations do not disturb net direction of CSF flow.

CONCLUSION

Blood-CSF and blood-brain barrier dysfunctions are an expression of reduced CSF or ISF flow rate.

Intrathecally produced CXCL13: A predictive biomarker in multiple sclerosis

Background

Clinicians caring for patients with Multiple Sclerosis (MS) need improved biomarkers to aid them in disease management.

Objective

We assessed the predictive value of the candidate biomarker CXCL13 index in comparison to oligoclonal bands (OCBs) and CSF neurofilament light (NfL) concentration, examining the ability of each biomarker to predict future disease activity in clinically and radiologically isolated syndromes, relapsing-remitting MS, and progressive MS.

Methods

Matched serum and CSF samples were obtained from 67 non-inflammatory neurologic disease patients and 67 MS patients. CSF and serum CXCL13 and CSF NfL were analyzed by Luminex and ELISA, respectively. CXCL13 data were also analyzed as CSF/serum ratios and indices. Electronic medical records were accessed to determine diagnosis, CSF profiles, and disease activity after the lumbar puncture.

Results

Among CXCL13 measures, CXCL13 index was the best predictor of future disease activity in MS patients (AUC = 0.82; CI = 0.69–0.95; p = 0.0002). CXCL13 index values were significantly elevated in activity-positive MS patients compared to activity-negative patients (p < 0.0001). As a single predictor, CXCL13 index outperformed both OCBs and CSF NfL in sensitivity, specificity, and positive and negative predictive value, for future disease activity in MS patients. Moreover, combining CXCL13 index and CSF NfL status improved sensitivity and predictive values for disease activity in MS patients.

Conclusions

The CXCL13 index is an excellent candidate prognostic biomarker for disease activity in patients with MS.

High levels of serum soluble TWEAK are associated with neuroinflammation during multiple sclerosis

Background

Inflammation and demyelination are the main processes in multiple sclerosis. Nevertheless, to date, blood biomarkers of inflammation are lacking. TWEAK, a transmembrane protein that belongs to the TNF ligand family, has been previously identified as a potential candidate.

Methods

Twenty-eight patients (9 males, 19 females) were prospectively included after a first clinical episode suggestive of multiple sclerosis and clinically followed during 3 years. Fifty-seven healthy controls were also included. TWEAK serum levels and MRI exams including magnetization transfer imaging were performed at baseline, 6- and 12-month follow-up.

Results

TWEAK serum levels were significantly increased in the patient group (mean baseline = 1086 ± 493 pg/mL, mean M6 = 624 ± 302 pg/mL and mean M12 = 578 ± 245 pg/mL) compared to healthy controls (mean = 467 ± 177 pg/mL; respectively p < 0.0001, 0.01 and 0.06). Serum levels of soluble TWEAK were significantly increased during relapses, compared to time periods without any relapse (respectively 935 ± 489 pg/mL and 611 ± 292 pg/mL, p = 0.0005). Moreover, patients presenting at least one gadolinium-enhanced CNS lesion at baseline (n = 7) displayed significantly increased serum TWEAK levels in comparison with patients without any gadolinium-enhanced lesion at baseline (n = 21) (respectively 1421 ± 657 pg/mL vs 975 ± 382 pg/mL; p = 0.02). Finally, no correlation was evidenced between TWEAK serum levels and the extent of brain tissue damage assessed by magnetization transfer ratio.

Conclusions

The present study showed that TWEAK serum levels are increased in MS patients, in relation to the disease activity. This simple and reproducible serum test could be used as a marker of ongoing inflammation, contributing in the follow-up and the care of MS patients. Thus, TWEAK is a promising serum marker of the best window to perform brain MRI, optimizing the disease control in patients.

The MRZ reaction helps to distinguish rheumatologic disorders with central nervous involvement from multiple sclerosis

BACKGROUND

Some rheumatologic disorders may initially manifest with central nervous system (CNS) affection, mimicking the clinical, magnetic resonance imaging, and cerebrospinal fluid findings of multiple sclerosis (MS). The MRZ reaction (MRZR), composed of the three respective antibody indices (AIs) against measles, rubella, and varicella zoster virus, has been found positive frequently in MS patients. However, it is unclear whether the MRZR is helpful to distinguish rheumatologic disorders with CNS involvement (RDwCNS) from MS.

METHODS

The MRZR was evaluated in patients with RDwCNS (n = 23), MS (n = 46; age and sex matched to patients with RDwCNS), and other inflammatory autoimmune neurological diseases affecting the CNS (OIND; n = 48). Both the stringency levels that have been used in previous MRZR studies, MRZR-1 (≥ 1 of 3 AIs positive) and MRZR-2 (≥ 2 of 3 AIs positive), were applied.

RESULTS

There was no statistically significant difference in the prevalence of positive MRZR between patients with RDwCNS (MRZR-1: 13.0% and MRZR-2: 8.7%, respectively) and OIND (MRZR-1: 22.9% and MRZR-2: 8.3%, respectively). Compared to these two study cohorts, the MS group exhibited significantly higher prevalences of positive MRZR (MRZR-1: 82.6%, MRZR-2: 63.0%; p < 0.005 each).

CONCLUSIONS

Considering the high specificity of MRZR-2 for MS found in this study, MRZR-2 can be a useful diagnostic tool for distinguishing MS from RDwCNS or OIND.

[Cerebrospinal fluid diagnostics in multiple sclerosis]

As a chronic inflammatory disease of the central nervous system (CNS), multiple sclerosis (MS) is associated with characteristic abnormalities in cerebrospinal fluid (CSF). Thus, in addition to magnetic resonance imaging, CSF examination is a central diagnostic procedure in patients with MS, which can corroborate a diagnosis of MS and may also help to discern differential diagnoses. The most important CSF finding in MS is the detection of persistent polyspecific intrathecal immunoglobulin synthesis. This review summarizes CSF findings of patients with MS and addresses issues of relevance for clinical practice, potential diagnostic pitfalls as well as new developments in CSF diagnostics of MS.

Albumin and multiple sclerosis

Leakage of the blood-brain barrier (BBB) is a common pathological feature in multiple sclerosis (MS). Following a breach of the BBB, albumin, the most abundant protein in plasma, gains access to CNS tissue where it is exposed to an inflammatory milieu and tissue damage, e.g., demyelination. Once in the CNS, albumin can participate in protective mechanisms. For example, due to its high concentration and molecular properties, albumin becomes a target for oxidation and nitration reactions. Furthermore, albumin binds metals and heme thereby limiting their ability to produce reactive oxygen and reactive nitrogen species. Albumin also has the potential to worsen disease. Similar to pathogenic processes that occur during epilepsy, extravasated albumin could induce the expression of proinflammatory cytokines and affect the ability of astrocytes to maintain potassium homeostasis thereby possibly making neurons more vulnerable to glutamate exicitotoxicity, which is thought to be a pathogenic mechanism in MS. The albumin quotient, albumin in cerebrospinal fluid (CSF)/albumin in serum, is used as a measure of blood-CSF barrier dysfunction in MS, but it may be inaccurate since albumin levels in the CSF can be influenced by multiple factors including: 1) albumin becomes proteolytically cleaved during disease, 2) extravasated albumin is taken up by macrophages, microglia, and astrocytes, and 3) the location of BBB damage affects the entry of extravasated albumin into ventricular CSF. A discussion of the roles that albumin performs during MS is put forth.

Oral pharmacotherapy for overactive bladder in older patients: mirabegron as a potential alternative to antimuscarinics

OBJECTIVE

Overactive bladder (OAB) is a particular challenge to treat in older adults with co-morbid conditions taking multiple medications. Antimuscarinics (e.g., solifenacin, fesoterodine) and β3-adrenergic receptor agonists (mirabegron) are similarly efficacious; however, antimuscarinics may be associated with side effects that result in poor persistence and contribute to anticholinergic burden, particularly in those taking other medications with anticholinergic properties. With a mechanism of action distinct from antimuscarinics, mirabegron has a different tolerability profile and does not contribute to anticholinergic burden. The objective of this review was to compare and contrast the tolerability profiles of antimuscarinics and mirabegron in older patients to inform practice.

METHODS

Prospective trials or retrospective subgroup analyses of antimuscarinics for the treatment of OAB in older patients were identified through a search of PubMed. Tolerability data and results of subgroup analyses of mirabegron in patients aged ≥65 and ≥75 years from a pooled analysis of three trials each of 12 weeks and a 1 year trial are described.

RESULTS

Anticholinergic adverse events (AEs) including dry mouth and constipation were more frequent with antimuscarinics versus mirabegron. In patients aged ≥65 years, dry mouth occurred with a six-fold higher incidence with tolterodine extended-release (ER) 4 mg than with mirabegron 25 mg or 50 mg over 12 weeks, and a three-fold higher incidence with tolterodine ER than mirabegron 50 mg over 1 year. Mirabegron had a low incidence of central nervous system effects. A systematic review of the cardiovascular safety profile of mirabegron has not identified any clinically significant effects on blood pressure or pulse rate at therapeutic doses amongst patients aged ≥65 years.

CONCLUSIONS

Mirabegron has a more favorable tolerability profile than antimuscarinics amongst older patients and may provide an improved benefit-to-risk ratio and therefore be considered as an alternative to antimuscarinics for older patients.

Increased albumin CSF/serum ratio in dementia with Lewy bodies

BACKGROUND

Alterations in the CSF/serum albumin ratio (Qalb) is currently recognized as one of the most reliable markers of blood-brain barrier impairment and blood-CSF barrier permeability, but its potential role as a biomarker in the differential diagnosis of neurological diseases has been poorly analysed.

METHODS

We evaluated Qalb and core CSF biomarkers (Tau, p-Tau and Aβ42) in a large patient population of neurological and neurodegenerative cases. Diagnostic test evaluation was assessed by ROC-AUC analysis.

RESULTS

In the differential diagnostic analysis, increased Qalb was found in dementia with Lewy bodies (DLB) patients compared to other diseases, either individually or stratified in non-dementia and dementia groups. When clinical groups were analysed individually and compared to controls, Qalb was also increased in stroke and Parkinson's disease dementia (PDD) cases, but not in Parkinson's disease (PD). Qalb in DLB cases correlate with CSF Aβ42 levels but not with Tau and p-Tau levels. Due to the lower CSF Aβ42 levels in DLB compared to PD and PDD, the potential clinical applicability of Qalb with respect to the DLB diagnosis is increased in combination with CSF Aβ42 analysis.

CONCLUSIONS

The present study demonstrates increased Qalb in synucleinopathies associated with dementia revealing a potential new clinical approach for the differential diagnosis of DLB.

Imaging biomarkers of angiogenesis and the microvascular environment in cerebral tumours

Conventional contrast-enhanced CT and MRI are now in routine clinical use for the diagnosis, treatment and monitoring of diseases in the brain. The presence of contrast enhancement is a proxy for the pathological changes that occur in the normally highly regulated brain vasculature and blood-brain barrier. With recognition of the limitations of these techniques, and a greater appreciation for the nuanced mechanisms of microvascular change in a variety of pathological processes, novel techniques are under investigation for their utility in further interrogating the microvasculature of the brain. This is particularly important in tumours, where the reliance on angiogenesis (new vessel formation) is crucial for tumour growth, and the resulting microvascular configuration and derangement has profound implications for diagnosis, treatment and monitoring. In addition, novel therapeutic approaches that seek to directly modify the microvasculature require more sensitive and specific biological markers of baseline tumour behaviour and response. The currently used imaging biomarkers of angiogenesis and brain tumour microvascular environment are reviewed.

Plasma cells in the central nervous system in the Theiler's virus model of multiple sclerosis

BACKGROUND

Immunoglobulin production within the central nervous system (CNS) is a prominent feature of multiple sclerosis and its animal model induced by infection with Theiler's meningoencephalitis virus, as well as of other inflammatory and infectious neurological diseases. However, relatively little is known about the plasma cells (PCs) responsible for producing Ig within the CNS.

METHODOLOGY

We induced Theiler's-induced demyelinating disease, characterized by disability, inflammation, and demyelination. We used immunofluorescence to localize and characterize IgG-producing cells, and correlated the morphology with results from CSF and tissue analysis.

RESULTS

Confidence that IgG production occurred within the CNS was gained by demonstrating high levels of IgG in the cerebrospinal fluid in the absence of blood-CSF barrier or blood-brain barrier breakdown. CNS IgG-producing cells were CD138+, like IgG-producing cells elsewhere in the body. Less than 5% of IgG-positive cells were Ki67-positive, indicating that most were nonproliferative PCs. The PCs were present primarily in perivascular infiltrates and in the meninges. Isolated PCs could be found in the CNS parenchyma, and, when present, were largely in demyelinated regions of the cord.

SIGNIFICANCE

These results demonstrate that PCs are a significant part of this chronic progressive disabling demyelinating disease, and suggest the possibility that these cells play a role in CNS injury by their secretion of immunoglobulin.

Blood-brain barrier permeability correlates with medial temporal lobe atrophy but not with amyloid-beta protein transport across the blood-brain barrier in Alzheimer's disease

BACKGROUND/AIMS

Alterations in the blood-brain barrier (BBB) may play an important role in the pathogenesis and treatment of Alzheimer's disease (AD). We investigated BBB disturbance and its influence on the equilibrium of amyloid-beta protein (Abeta) between plasma and cerebrospinal fluid (CSF) in AD patients.

METHODS

We analyzed albumin ratio as a marker of the BBB permeability and correlated it with the severity of dementia, brain atrophy on MRI, apolipoprotein E isoform, CSF levels of total tau, CSF and plasma levels of Abeta 1-40 (Abeta40) and 1-42 (Abeta42), and CSF/plasma ratios of Abeta40 and Abeta42 in 42 AD patients.

RESULTS

The albumin ratio was positively correlated with the severity of medial temporal lobe atrophy but not with the other parameters including CSF/plasma ratios of Abeta40 or Abeta42.

CONCLUSION

Our results suggest that progression of medial temporal lobe atrophy is associated with increased BBB permeability and that the transport of Abeta across the BBB is not influenced by the BBB alteration in AD.

Muscarinic receptors: their distribution and function in body systems, and the implications for treating overactive bladder

1. The effectiveness of antimuscarinic agents in the treatment of the overactive bladder (OAB) syndrome is thought to arise through blockade of bladder muscarinic receptors located on detrusor smooth muscle cells, as well as on nondetrusor structures. 2. Muscarinic M3 receptors are primarily responsible for detrusor contraction. Limited evidence exists to suggest that M2 receptors may have a role in mediating indirect contractions and/or inhibition of detrusor relaxation. In addition, there is evidence that muscarinic receptors located in the urothelium/suburothelium and on afferent nerves may contribute to the pathophysiology of OAB. Blockade of these receptors may also contribute to the clinical efficacy of antimuscarinic agents. 3. Although the role of muscarinic receptors in the bladder, other than M3 receptors, remains unclear, their role in other body systems is becoming increasingly well established, with emerging evidence supporting a wide range of diverse functions. Blockade of these functions by muscarinic receptor antagonists can lead to similarly diverse adverse effects associated with antimuscarinic treatment, with the range of effects observed varying according to the different receptor subtypes affected. 4. This review explores the evolving understanding of muscarinic receptor functions throughout the body, with particular focus on the bladder, gastrointestinal tract, eye, heart, brain and salivary glands, and the implications for drugs used to treat OAB. The key factors that might determine the ideal antimuscarinic drug for treatment of OAB are also discussed. Further research is needed to show whether the M3 selective receptor antagonists have any advantage over less selective drugs, in leading to fewer adverse events.

Blood-Brain Barrier Imaging and Therapeutic Potentials

Much work has been done in the last several decades to improve the understanding of the molecular composition of the blood-brain barrier (BBB). Advances in magnetic resonance imaging have resulted in development of dynamic magnetic resonance imaging techniques to quantify permeability measurements across the brain endothelium. This review describes the basic anatomical and biochemical concepts of a BBB and the various techniques for magnetic resonance measurement of BBB permeability. To date, BBB permeability data have been shown to be useful in preoperative brain tumor grading and potentially also in determining the effectiveness of selective types of therapy. Explorative studies are evaluating new strategies for safe and effective altering of the BBB permeability to improve local drug delivery into brain tumors. As new antiangiogenesis drugs become available, BBB permeability imaging may also become critical as a surrogate angiogenesis marker to monitor tumor response to these agents. Finally, BBB permeability data may also prove useful in future applications to guide therapy in other nontumoral disease processes such as acute cerebral ischemia and inflammatory processes such as multiple sclerosis.

Treatment of Overactive Bladder in the Older Patient: Pooled Analysis of Three Phase III Studies of Darifenacin, an M3 Selective Receptor Antagonist

AIM

To evaluate the efficacy, tolerability and safety of darifenacin, an M(3) selective receptor antagonist, in the subgroup of older patients from a pooled analysis of three phase III, multicentre, randomized, double-blind clinical trials in patients with overactive bladder (OAB).

PATIENTS AND METHODS

317 patients aged > or =65 years with OAB symptoms (urge incontinence, urgency and frequency) received up to 12 weeks' oral treatment with darifenacin 7.5 mg or 15 mg once daily or matching placebo. Efficacy was evaluated from daily electronic diary records. Safety endpoints included withdrawal rates and treatment-related adverse events.

RESULTS

Darifenacin treatment of patients aged > or =65 years was associated with a dose-related, significant improvement of all the major symptoms of OAB. At week 12, the median reduction in incontinence episodes/week was greater with darifenacin 7.5 mg or 15 mg than in the corresponding placebo arms (66.7% vs. 34.8% and 75.9% vs. 44.8%, respectively, both p < 0.001). Both doses were also significantly superior to placebo in improving micturition frequency (both p < 0.001), bladder capacity (volume voided) (darifenacin 7.5 mg, p = 0.018, darifenacin 15 mg, p < 0.001), and the frequency of urgency episodes (both p < 0.001). Darifenacin was well tolerated. The most common treatment-related adverse events were dry mouth (7.5 mg, 20.6%; 15 mg, 30.9%; placebo, 4.5%) and constipation (7.5 mg, 18.6%; 15 mg, 23.6%; placebo, 6.4%), typically mild or moderate. Use of constipation remedies (laxatives, stool softeners or fibre supplements) was low and similar between groups (7.5 mg, 10.3%; 15 mg, 16.4%; placebo, 10.0%). There were few withdrawals due to treatment-related adverse events (7.5 mg, 1.0%; 15 mg, 9.1%; placebo, 2.7%), and no nervous system or cardiovascular safety concerns.

CONCLUSIONS

The results demonstrate excellent efficacy, tolerability and safety with darifenacin 7.5 mg and 15 mg once-daily treatment for OAB in older patients.

Antimuscarinic agents: Implications and concerns in themanagement of overactive bladder in the elderly

BACKGROUND

Overactive bladder (OAB) is a widespread problem that has a negative effect on quality of life, particularly among the elderly. Antimuscarinic agents are the only drug class with broad, accepted efficacy in the treatment of OAB. Their clinical usefulness, however, is limited by dose-dependent adverse effects. In the elderly, the most serious of these is central nervous system (CNS) dysfunction, including cognitive impairment.

OBJECTIVE

This article examines currently available antimuscarinic agents for the treatment of OAB in terms of their likelihood of causing CNS dysfunction by crossing the blood-brain barrier (BBB) and blocking muscarinic type 1 (Ml) receptor sites in the brain.

METHODS

Pertinent studies were selected from a comprehensive review of the OAB literature with a focus on muscarinic receptor-associated mechanisms leading to CNS adverse effects and their potential impact on elderly patients. MEDLINE was searched for articles published in the past 10 years, and additional articles were obtained from the reference lists of identified publications. Also searched were abstracts of recent meetings of the International Consultation on Incontinence, International Continence Society, American Urological Association, and European Association of Urology.

RESULTS

Antimuscarinic agents control involuntary detrusor muscle contractions through cholinergic blockade at the muscarinic receptors. The prevalence of OAB is highest in the elderly, the population most likely to be taking multiple anticholinergic medications and most vulnerable to the CNS adverse effects of these agents. Nonselective antimuscarinic agents that bind to the Ml receptor are most likely to cause significant cognitive adverse effects compared with the more selective antimuscarinic agents for the treatment of OAB.

CONCLUSIONS

When considering use of an antimuscarinic agent for the treatment of OAB in elderly patients, prescribers should routinely consider the agent's receptor selectivity and ability to cross the BBB. The medical history should include all current medications that may contribute to the anticholinergic burden and cognitive impairment. Patients and caregivers should be educated to recognize anticholinergic adverse effects.

Potential role of MCP-1 in endothelial cell tight junction 'opening': signaling via Rho and Rho kinase

The expression of the monocyte chemoattractant protein-1 (MCP-1) receptor CCR2 by brain endothelial cells suggests that MCP-1 may have other functions than purely driving leukocyte migration into brain parenchyma during inflammation. This study examines one of these potential novel roles of MCP-1 regulation of endothelial permeability using primary cultures of mouse brain endothelial cells. MCP-1 induces reorganization of actin cytoskeleton (stress fiber formation) and redistribution of tight junction proteins, ZO-1, ZO-2 occludin and claudin-5, from the Triton X-100-soluble to the Triton X-100-insoluble fractions. These morphological changes are associated with a decrease in transendothelial electrical membrane resistance and an increase in [14C]inulin permeability. MCP-1 did not induce these events in brain endothelial cells prepared from mice genotype CCR2-/-. The Rho kinase inhibitor Y27632 and inhibition of Rho (C3 exoenzyme, and dominant negative mutant of Rho, RhoT19N) prevented MCP-1-induced stress fiber assembly, reorganization of tight junction proteins and alterations in endothelial permeability. In all, this suggests that a small GTPase Rho and Rho kinase have a pivotal role in MCP-1-induced junction disarrangement. These data are the first to strongly suggest that MCP-1, via CCR2 present on brain endothelial cells, contributes to increased brain endothelial permeability.

Cerebrospinal fluid--physiology, analysis and interpretation of protein patterns for diagnosis of neurological diseases

The state of the art in routine CSF analysis is reviewed with particular reference to multiple sclerosis regarding: (1) The physiology and pathophysiology of blood-CSF barrier function and dysfunction with the CSF flow rate as main modulator of blood- and brain-derived protein concentrations in CSF; (2) The neuroimmunological aspects regarding (a) patterns of disease-related immunoglobulin class response (IgG, IgA, IgM) in actual Reiber graphs with reference to specific parameters and optional tests, and (b) the oligoclonal, polyspecific antibody synthesis in brain; (3) Particular marker proteins in CSF and blood for differential diagnosis of neurological diseases; (4) Mathematical base for evaluations of CSF data with an example of a multiple sclerosis patient for calculation of intrathecal immunoglobulin and antibody synthesis as well as Antibody Index.