Vascular endothelial dysfunction associated with severity in multiple sclerosis

Prevalence and epidemiology of stroke in patients with multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

Epidemiological data are sparse regarding the risk of stroke in patients with multiple sclerosis (MS).

OBJECTIVE

To estimate the following: (1) the pooled prevalence of all-cause stroke, acute ischaemic stroke (AIS) and intracerebral haemorrhage (ICH) in MS patients; (2) the relative risk for all-cause stroke, AIS and ICH in MS patients compared to the general population; (3) associations between patient characteristics and the risk for AIS and ICH in MS patients.

METHODS

Systematic review and meta-analysis of registry-based and cohort studies.

RESULTS

Thirteen observational studies comprising 146,381 MS patients were included. The pooled prevalence of all-cause stroke was 2.7% (95% confidence interval [CI] 1.3-4.6%), with the relative risk of all-cause stroke being higher in MS patients compared to the general population (RR: 2.55; 95% CI 1.97-3.29). Subgroup analyses per stroke subtype revealed a pooled AIS prevalence of 2.1% (95% CI 0.8-4.1%) and a pooled ICH prevalence of 0.6% (95% CI 0.2-1.2%). Compared to the general population, patients with MS were found to harbour an increased risk for AIS (RR: 2.79; 95% CI 2.27-3.41) and ICH (RR: 2.31; 95% CI 1.04-5.11), respectively. The pooled prevalence of cardiovascular risk factors in MS patients was 11.5% (95% CI 2.9-24.7%) for dyslipidaemia, 18.2% (95% CI 5.9-35.3%) for hypertension and 5.4% (95% CI 2.1-10.2%) for diabetes. In meta-regression, age was negatively associated with AIS risk (β =  - .03, p = 0.04), with a 1-year increase in age resulting in a significant 3% (95%CI 0-5) attenuation of the risk of AIS.

CONCLUSION

The findings of the present meta-analysis indicate that MS is associated with an increased risk for ischaemic and haemorrhagic stroke. Future well-designed epidemiological studies are warranted to corroborate the robustness of the present findings in the MS population.

Reduced resting beat-to-beat blood pressure variability in females with relapsing-remitting multiple sclerosis

BACKGROUND

Relapsing-remitting multiple sclerosis (RRMS) is a demyelinating disease of the central nervous system and cardiovascular autonomic dysfunction has been well documented in this population. The sympathetic nervous system contributes to beat-to-beat blood pressure regulation primarily by baroreflex control of the peripheral vasculature which may be impaired in females with RRMS. Even at rest, attenuated sympathetic control of vasomotor tone may result in large and frequent blood pressure excursions (i.e., greater blood pressure variability). Therefore, the primary purpose of this investigation was to test the following hypotheses; (1) females with RRMS have augmented beat-to-beat blood pressure variability compared to healthy controls and (2) reduced sympathetic baroreflex sensitivity in females with RRMS is related to augmented blood pressure variability.

METHODS

Electrocardiogram and beat-to-beat blood pressure were continuously recorded during 8-10 min of supine rest in 26 females with clinically definite RRMS and 24 sex-, age- and BMI- matched healthy controls. Muscle sympathetic nerve activity (MSNA) was recorded in a subset of participants (MS, n = 15; CON, n = 14). Traditional statistical measurements of dispersions were used to index beat-to-beat blood pressure variability. Spontaneous sympathetic baroreflex sensitivity was quantified by sorting diastolic blood pressures into 3 mmHg bins and calculating MSNA burst incidence within each bin. Weighted linear regression was then used to account for the number of cardiac cycles in each bin and calculate slopes. Spontaneous cardiac baroreflex sensitivity was determined using the sequence method.

RESULTS

Groups had similar resting mean arterial pressure (MAP), systolic blood pressure (SBP), diastolic blood pressure (DBP), MSNA burst frequency and MSNA burst incidence (All P > 0.05). The standard deviation and interquartile range of MAP, SBP and DBP were less in females with RRMS compared to healthy controls (All P < 0.05). There were no between groups differences in sympathetic baroreflex sensitivity or cardiac baroreflex sensitivity (Both P > 0.05) and baroreflex sensitivity measures were not related to any indices of blood pressure variability (Both P > 0.05).

CONCLUSION

These data suggest that females with RRMS have reduced beat-to-beat blood pressure variability. However, this does not appear to be related to changes in sympathetic or cardiac baroreflex sensitivity.

Combination among VEP, OCT and TCD data in patients with relapsing-remitting multiple sclerosis during attack-free period

AIMS

Multiple sclerosis (MS) is characterized by inflammation, demyelination, glial cell pathology and axonal injury in the central nervous system, and also progressive axonal loss of the optic nerve in cases with optic neuritis (ON). The previous transcranial Doppler (TCD) investigations suggest cortical hyperreactivity in patients with relapsing-remitting Multiple sclerosis (RRMS). We investigated the effect of ON involvement on visual reactivity.

MATERIAL AND METHODS

One hundred thirty patients with RRMS during attack-free period and 12 healthy subjects were enrolled to the study. Visual evoked potential (VEP), optic coherence tomography (OCT) and TCD examinations of all subjects were performed.

RESULTS

Cerebrovascular reactivity measured with breath holding (BH) test was found to be normal. VEP amplitude, visual reactivity and peripapillary retinal nerve fibre layer (pRNFL) measurements were found to be low in patients with ON involvement, whereas VEP latencies were long. Visual reactivity was negatively correlated with VEP amplitude and RFNL measurements, and positively correlated with VEP latency.

CONCLUSIONS

The present study supports that cerebrovascular reactivity is preserved in patients with RRMS except for attacks, and neurovascular reactivity is increased in patients without ON involvement.

Vascular dysfunction in multiple sclerosis: Scoping review of current evidence for informing future research directions

BACKGROUND

The research involving vascular comorbidity in people with multiple sclerosis (MS) could be advanced through investigations applying measurements of vascular function such as pulse wave velocity or flow mediated dilation as mechanistic endpoints in the study of physical comorbidity management in MS across the lifespan. We conducted a scoping review of research on vascular function parameters and outcomes in MS and developed a research agenda for future inquiry.

METHODS

We searched PubMed from inception through February 2023 for articles involving relevant central and peripheral vascular function data or correlates of vascular function (arterial stiffness, endothelial function, blood pressure parameters, etc.) in conjunction with relevant outcomes (walking function, cognition, etc.) in MS. Studies were limited to English-language and primary research articles.

RESULTS

Our search and subsequent screening identified 10 relevant articles. Four papers focused on arterial stiffness and reported pulse wave velocity and arterial compliance in MS compared with controls. Two papers focused on endothelial function and reported flow-mediated dilation in MS compared with controls. There was evidence that arterial stiffness and endothelial function were associated with cognition and disease progression in MS, respectively. One paper reported that physical activity was associated with arterial stiffness in MS. There was one protocol paper examining the effect of a home-based exercise program on markers of subclinical atherosclerosis; however, the results are unpublished, and there was no literature beyond this surrounding the impact of lifestyle behavior (e.g., diet) or exercise interventions on vascular function.

CONCLUSION

There is emerging evidence for vascular dysfunction in MS, and this is associated with cognition and disease progression; we know very little about approaches for managing vascular dysfunction in MS. To that end, we offer an agenda for research on measurements and outcomes of vascular function in relation to MS and disease attributes, along with proposed mechanisms and lifestyle changes that could aid in managing vascular dysfunction.

Multiple Sclerosis: Inflammatory and Neuroglial Aspects

Multiple sclerosis (MS) represents the most common acquired demyelinating disorder of the central nervous system (CNS). Its pathogenesis, in parallel with the well-established role of mechanisms pertaining to autoimmunity, involves several key functions of immune, glial and nerve cells. The disease's natural history is complex, heterogeneous and may evolve over a relapsing-remitting (RRMS) or progressive (PPMS/SPMS) course. Acute inflammation, driven by infiltration of peripheral cells in the CNS, is thought to be the most relevant process during the earliest phases and in RRMS, while disruption in glial and neural cells of pathways pertaining to energy metabolism, survival cascades, synaptic and ionic homeostasis are thought to be mostly relevant in long-standing disease, such as in progressive forms. In this complex scenario, many mechanisms originally thought to be distinctive of neurodegenerative disorders are being increasingly recognized as crucial from the beginning of the disease. The present review aims at highlighting mechanisms in common between MS, autoimmune diseases and biology of neurodegenerative disorders. In fact, there is an unmet need to explore new targets that might be involved as master regulators of autoimmunity, inflammation and survival of nerve cells.

Roles of Oxidative Stress and Inflammation in Vascular Endothelial Dysfunction-Related Disease

Oxidative stress and chronic inflammation play an important role in the pathogenesis of atherosclerosis. Atherosclerosis develops as the first step of vascular endothelial dysfunction induced by complex molecular mechanisms. Vascular endothelial dysfunction leads to oxidative stress and inflammation of vessel walls, which in turn enhances vascular endothelial dysfunction. Vascular endothelial dysfunction and vascular wall oxidative stress and chronic inflammation make a vicious cycle that leads to the development of atherosclerosis. Simultaneously capturing and accurately evaluating the association of vascular endothelial function with oxidative stress and inflammation would be useful for elucidating the pathophysiology of atherosclerosis, determining treatment efficacy, and predicting future cardiovascular complications. Intervention in both areas is expected to inhibit the progression of atherosclerosis and prevent cardiovascular complications.

Cerebrovascular Reactivity and Neurovascular Coupling in Multiple Sclerosis-A Systematic Review

The inflammatory processes observed in the central nervous system in multiple sclerosis (MS) could damage the endothelium of the cerebral vessels and lead to a dysfunctional regulation of vessel tonus and recruitment, potentially impairing cerebrovascular reactivity (CVR) and neurovascular coupling (NVC). Impaired CVR or NVC correlates with declining brain health and potentially plays a causal role in the development of neurodegenerative disease. Therefore, we examined studies on CVR or NVC in MS patients to evaluate the evidence for impaired cerebrovascular function as a contributing disease mechanism in MS. Twenty-three studies were included (12 examined CVR and 11 examined NVC). Six studies found no difference in CVR response between MS patients and healthy controls. Five studies observed reduced CVR in patients. This discrepancy can be because CVR is mainly affected after a long disease duration and therefore is not observed in all patients. All studies used CO₂ as a vasodilating stimulus. The studies on NVC demonstrated diverse results; hence a conclusion that describes all the published observations is difficult to find. Future studies using quantitative techniques and larger study samples are needed to elucidate the discrepancies in the reported results.

Acute myocardial infarction risk in multiple sclerosis and neuromyelitis optica spectrum disorder: A nationwide cohort study in South Korea

BACKGROUND

The link between neuromyelitis optica spectrum disorder (NMOSD) and cardiovascular disease is currently unclear.

OBJECTIVE

To determine the acute myocardial infarction (MI) risk in patients with MS and NMOSD.

METHODS

This study analyzed the Korean National Health Insurance Service database between January 2010 and December 2017. The included patients comprised 1503/1675 adults with MS/NMOSD who had not experienced ischemic heart disease or ischemic stroke at the index date. Matched controls were selected based on age, sex, and the presence of hypertension, diabetes mellitus (DM), and dyslipidemia.

RESULTS

The risks of developing MI were 2.61 (hazard ratio (HR), 95% confidence interval (CI) 1.73-3.95) and 1.95 (95% CI = 1.18-3.22) times higher in MS and NMOSD compared with the control populations. Patients with NMOSD had a similar MI risk compared with patients with MS, after adjusting for age, sex, income, hypertension, DM, and dyslipidemia (HR = 0.59, 95% CI = 0.34-1.02, p = 0.059). Among each patient group, the MI risk did not differ significantly with age (20-39, 40-64 or ⩾65 years), sex, or the presence of hypertension, DM, or dyslipidemia.

CONCLUSION

The MI risk increased in MS and NMOSD and seemed to be comparable between NMOSD and MS.

Multiple Sclerosis and the Risk of Cardiovascular Diseases: A Mendelian Randomization Study

BACKGROUND

Observational studies suggested that multiple sclerosis (MS) is associated with cardiovascular diseases (CVDs). However, the causal association has not been fully elucidated. Thus, we aim to assess the causality of the associations of MS with risk of CVDs.

METHODS

A two-sample Mendelian randomization (MR) study was performed to explore the causality. Genetic instruments were identified for MS from a genome-wide association study (GWAS) involving 115,803 individuals. Summary-level data for CVDs were obtained from different GWAS meta-analysis studies. MR analysis was conducted mainly using the inverse-variance weighted (IVW) method. Sensitivity analyses were further performed to ensure the robustness of the results.

RESULTS

This MR study found suggestive evidence that genetic liability to MS was associated with an increased risk of coronary artery disease (CAD) [odds ratio (OR), 1.02; 95% confidence interval (CI), 1.00-1.04; p = 0.03], myocardial infarction (MI) (OR, 1.03; 95% CI, 1.00-1.06; p = 0.01), heart failure (HF) (OR, 1.02; 95% CI, 1.00-1.04; p = 0.02), all-cause stroke (AS) (OR, 1.02; 95% CI, 1.00-1.05; p = 0.02), and any ischemic stroke (AIS) (OR, 1.02; 95% CI, 1.00-1.05; p = 0.04). The null-association was observed between MS and the other CVDs. Further analyses found little evidence of pleiotropy.

CONCLUSIONS

We provided suggestive genetic evidence for the causal associations of MS with increased risk of CAD, MI, HF, AS, and AIS, which highlighted the significance of active monitoring and prevention of cardiovascular risk to combat cardiovascular comorbidities in MS patients.

Atherosclerosis and multiple sclerosis: An overview on the prevalence of risk factors

BACKGROUND

Atherosclerosis is the leading cause of ischemic heart disease and coronary artery disease. The process of atherosclerosis develops over a period of years and is mainly immune-mediated. Data regarding the prevalence of vascular disease and atherosclerosis among people with multiple sclerosis (pwMS) is inconsistent, therefore, we aimed to provide an overview of the prevalence of atherosclerotic risk factors in pwMS.

METHODS

This is a cross-sectional study over a period of one year among pwMS visiting the Isfahan MS center. Study data have been extracted using participants' files and a checklist that was completed by the observers. Only people with relapsing-remitting (RRMS) and secondary progressive (SPMS) forms of MS were included in the study. Participants with primary progressive (PPMS) disease are only described and have been excluded from analyses.

RESULTS

Of the 396 pwMS (343 with RRMS and 53 with SPMS), in descending order, the reported risk factors were tobacco smoking (18.4%), dyslipidemia (10%), hypertension (8.8%), and diabetes mellitus (4.5%). In people with RRMS, 17.4% were smokers, 9.9% had dyslipidemia, 8.1% had hypertension, and 4.3% had diabetes mellitus. In SPMS patients 24.5% reported a history of smoking, 13.2% had hypertension, 9.4% had dyslipidemia, and 3.7% had diabetes mellitus. Smoking was insignificantly associated with higher expanded disability status scale (Z: 1.70, p-value = 0.090). Male sex (RR [95%CI]: 1.628 [1.172, 2.261], p-value = 0.004) and increasing age (RR [95%CI]: 1.024 [1.008, 1.040], p-value = 0.003) were associated with a higher number of risk factors.

CONCLUSION

The highest observed atherosclerosis risk factor among pwMS was smoking. Diabetes mellitus was the least reported risk factor in our population as a whole. Overall, and in participants with RRMS, dyslipidemia and hypertension were the second and third most commonly reported risk factors, however, hypertension exceeded dyslipidemia in participants with SPMS. Male sex and increasing age were associated with a higher number of atherosclerosis risk factors.