Linkage of large-vessel carotid atherosclerotic stroke to inflammatory genes via a systematic screen

BACKGROUND

Inflammatory cytokines including the IL-1 family, TNF-alpha and IL-6 mediate the formation of thrombosis on the luminal surface of atherosclerotic plaques. Gene polymorphisms that regulate these cytokines' expression may explain part of the variation in susceptibility to stroke in patients with carotid atherosclerosis. The aim of this study was to evaluate the role of single-nucleotide polymorphisms (SNPs) and haplotypes in inflammatory genes as they relate to symptomatic carotid atherosclerosis.

METHODS

The study included 95 subjects with symptomatic (transient ischaemic attacks or stroke) and 113 subjects with asymptomatic carotid atherosclerotic disease. A panel of evenly spaced SNPs including previously reported functionally significant polymorphisms were genotyped for IL-1beta (10 SNPs), IL-1alpha (nine SNPs), IL-1RN (11 SNPs), IL-6 (seven SNPs) and TNF-alpha and TNF-beta (seven SNPs).

RESULTS

Using single SNP analysis, IL-1RN rs315934 (P=0.025), IL-1RN rs315946 (P=0.042), IL-1RN rs315921 (P=0.035), IL-6 rs1180243 (P=0.018) and IL-1alpha rs2071373 (P=0.025) were associated with decreased odds of symptomatic carotid disease. Additionally, two diplotypes of the IL-1RN gene (P=0.023 and 0.0064) and one diplotype in the IL-1alpha gene (P=0.02) were associated with a protective affect from cerebral ischaemic events. Logistic analysis for interaction of the protective SNPs reveals an additive effect of all SNP pair combinations.

CONCLUSION

These results suggest that genetic polymorphisms in proinflammatory genes may contribute to interindividual differences in the development of symptomatic carotid atherosclerotic disease.

Single nucleotide polymorphisms in monocyte chemoattractant protein-1 and its receptor act synergistically to increase the risk of carotid atherosclerosis

BACKGROUND

Monocyte chemoattractant protein 1 (MCP-1), acting in concert with its receptor chemokine receptor 2 (CCR2), promotes recruitment of macrophages into atherosclerotic plaque. We examined whether single nucleotide polymorphism (SNP) variants in the MCP-1 or CCR2 genes independently or in combination are associated with carotid artery atherosclerosis in an African American population at increased risk of vascular disease.

METHODS

Four SNPs in MCP-1 and 1 in CCR2 were genotyped. Carotid artery duplex ultrasonography was used to identify the presence or absence of carotid plaque >1 mm. The study population included 325 apparently healthy 30- to 59-year-old black siblings of 185 probands with premature coronary artery disease (<60 years old). Associations between each independent SNP and the presence of carotid plaque were examined using multivariate logistic regression models adjusted for age, sex, educational level, diabetes, smoking, hypertension, obesity, low-density lipoprotein cholesterol and non-independence within families. Interactions between SNPs in the MCP-1 gene and the SNP in the CCR2 gene were examined by multivariate analysis.

RESULTS

Siblings were 32% males, with a mean age of 46 +/- 7 years, and 77 (24%) demonstrated carotid plaque. In multivariate analyses, the CC genotype of MCP-1 SNP rs2857656 was independently associated with plaque (p = 0.05). Subjects who had both the MCP-1 CC genotype and were heterozygotic or homozygotic for the CCR2 V64I genotype (rs1799864; n = 12) had an even higher risk of carotid atherosclerosis (odds ratio 6.14, 95% confidence interval 1.82-20.73; p = 0.0037).

CONCLUSION

The MCP-1 rs2857656 CC genotype is independently associated with carotid artery plaque in African American from families with premature coronary artery disease. The combination of the MCP-1 CC homozygous genotype and the homozygotic or heterozygote CCR2 V64I genotype is associated with a particularly high prevalence of carotid artery plaque.

Types of brain dysfunction in critical illness

Cerebral dysfunction and injury in the ICU presents as focal neurologic deficits, seizures, coma, and delirium. These syndromes may result from a primary brain insult, such as stroke or trauma, but commonly are a complication of a systemic insult, such as cardiac arrest, hypoxemia, sepsis, metabolic derangements, and pharmacologic exposures. Many survivors of critical illness have cognitive impairment, which is believed to underlie the poor long-term functional status and quality of life observed in many critical illness survivors. Although progress has been made in characterizing the epidemiology of cerebral dysfunction in the ICU, more research is needed to elucidate underlying mechanisms that might represent targets for therapeutic intervention.

Management of spontaneous intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) has the highest mortality of all cerebrovascular events. Thirty-day mortality approaches 50%, and only 20% of survivors achieve meaningful functional recovery at 6 months. Many clinicians believe that effective therapies are lacking; however, this is changing because of new data on the pathophysiology and treatment of ICH, particularly research establishing the role of medical therapies to promote hematoma stabilization. This article provides updates to a recent publication discussing basic principles of ICH management, including initial stabilization, the prevention of hematoma growth, treatment of complications, and identification of the underlying etiology. Minimally invasive surgery (MIS) to reduce clot size is also discussed, with the goal of preserving neurologic function through reduction in parenchymal damage from edema formation.

The systemic implications of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is analogous to a pathophysiological watershed, disrupting brain integrity and function and precipitating an array of systemic derangements including cardiovascular, respiratory, endocrine, hematological, and immune dysfunction. Extracerebral organ dysfunction is closely linked to the magnitude of the primary neurological insult, suggesting neurogenic, neuroendocrine and neuroimmunomodulatory mechanisms. Systemic organ involvement is associated with increased mortality and neurological impairment, even after adjustment for other outcome predictors such as the severity of the initial neurological injury. This may be a reflection of secondary brain injury precipitated by hypoxemia, circulatory failure, fever, or hyperglycemia, all of which have been linked to adverse clinical outcomes. Interventions to avert or reverse these and other perturbations need to be tested in clinical trials as they represent opportunities to improve survival and neurological recovery in patients with SAH.

Advances in the management of spontaneous intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) is associated with the highest mortality of all cerebrovascular events, and most survivors never regain functional independence. Many clinicians believe that effective therapies are lacking for patients who have ICH; however, this perception is changing in light of new data on the pathophysiology and treatment of this disorder, in particular, research establishing the role of medical therapies to promote hematoma stabilization. This article discusses the basic principles of management of ICH, including initial stabilization, the prevention of hematoma growth, treatment of complications, and identification of the underlying etiology. In addition, minimally invasive surgery to reduce clot size is discussed, with the goal of preserving neurologic function through reduction in parenchymal damage from edema formation.

Coma, delirium, and cognitive dysfunction in critical illness

Syndromes of global cerebral dysfunction that are associated with critical illness include acute disorders (eg, coma, delirium) and chronic processes (ie, cognitive impairment). These syndromes can result from direct cerebral injury; however, many cases develop as a complication of a systemic insult. Coma frequently evolves into phenomenologically distinct disorders of consciousness; it must be differentiated from conditions in which consciousness is preserved, as in the locked-in state. Advances have been made in defining, scoring, and delineating the epidemiology of cerebral dysfunction in the ICU, but research is needed to elucidate underlying mechanisms, with the goal of identifying targets for prevention and therapy.

Detection of leukocyte activation in pigs with neurologic decompression sickness

BACKGROUND

In a porcine model of neurological decompression sickness (DCS), perivascular leukocyte activation was a consistent finding in biopsies of associated cutaneous DCS. This prompted examination of other organs for similar changes; multifocal leukocyte activation was found in the lungs (pneumonitis) and liver (hepatitis).

HYPOTHESIS

DCS in pigs induces leukocyte aggregation and activation in the liver and lungs.

METHODS

Male Yorkshire swine, trained to run on a modified treadmill, were compressed to 200 ft of seawater (fsw) in a dry, air-filled compression chamber. Decompression varied according to the profile under study.

RESULTS

In 106 pigs, evidence for association of leukocyte aggregation and activation with the clinical diagnosis of neurologic DCS was sought. The incidence of pneumonitis (20/68, 29% with DCS; 4/38, 10% without DCS) and hepatitis (23/68, 33% with DCS; 4/38, 10% without DCS) were strongly correlated with the incidence of neurologic DCS via Pearson Chi-squared analysis (p = 0.026 pneumonitis and p = 0.008 hepatitis). Additionally, Kruskal-Wallis rank analysis for numbers of organs involved and incidence of neurologic DCS showed a strong correlation between the increasing occurrence of neurologic DCS and the involvement of both the liver and lungs (p = 0.004).

CONCLUSIONS

The results imply that, at least in pigs, DCS induces leukocyte aggregation and activation in the liver and lungs. These organs are not normally considered targets of DCS. Leukocyte aggregation in these organs may be related to their roles as highly perfused organs. Leukocyte aggregation may be a marker for DCS, providing further evidence for wider, systemic effects of DCS.

Interleukin-1 receptor antagonist gene polymorphisms in carotid atherosclerosis

BACKGROUND AND PURPOSE

Inflammation plays an important role in the development of atherosclerosis. The gene for the counterinflammatory cytokine interleukin-1 receptor antagonist (IL-1ra) is polymorphic, and high frequencies of allele 2 have been found to be associated with other inflammatory diseases. This study examined the association of allele and carrier frequencies of the IL-1ra gene with the presence of carotid atherosclerosis and plaque symptomaticity.

METHODS

A total of 328 subjects identified as having carotid atherosclerosis or no atherosclerosis (controls) participated. Blood was obtained for DNA determination.

RESULTS

Frequency of allele 2 was significantly greater in patients with atherosclerosis compared with nonatherosclerotic subjects. No difference was seen between symptomatic and asymptomatic atherosclerosis patients. Noncarriage of allele 2 was associated with reduced likelihood of atherosclerosis (odds ratio [OR], 0.44; 95% CI, 0.27 to 0.71). The homozygous carrier state for allele 2 was associated with greater likelihood of atherosclerosis (unadjusted OR, 7.30; 95% CI, 2.31 to 22.94; adjusted OR, 13.78; 95% CI, 1.94 to 97.9). A gene-dose effect was detected.

CONCLUSIONS

These data suggest that allele 2 of the IL-1ra gene represents a susceptibility factor in the development of carotid atherosclerosis. Further investigation appears warranted.

Incidence of seizures in patients with multiple sclerosis: a population-based study

OBJECTIVE

To determine whether multiple sclerosis (MS) is associated with occurrence of seizure activity.

PATIENTS AND METHODS

The medical records of all incidence patients with MS in Olmsted County, Minnesota, from 1935 to 1991 were reviewed. The incidence of seizures was calculated by using 3 methods: including only seizures that occurred after definite diagnosis of MS, including all seizures occurring after onset of the first symptoms of MS, and including any seizures regardless of the time of onset relative to MS. These incidences were age-adjusted to the 1970 US population and then compared with the age-adjusted incidence rate of seizures in the general population of Olmsted County.

RESULTS

The age-adjusted incidence of seizures among MS patients was not significantly higher than the age-adjusted incidence of seizures in the general population of Olmsted County. The age-adjusted incidence of first unprovoked seizures in Rochester, Minn, was 61 per 100,000 person-years. In patients with the definite diagnosis of MS, the age-adjusted Incidence was calculated at 61 per 100,000 person-years (95% confidence interval [CI], 7-114). In the group with seizures after onset of symptoms, the age-adjusted incidence rate was 80 per 100,000 person-years (95% CI, 24-135). In the group with seizures at any time in their life, the age-adjusted incidence rate was 82 per 100,000 person-years (95% CI, 41-158).

CONCLUSION

The present study does not suggest that occurrence of seizures is more common in MS patients than in the general population.

Seizures in patients with multiple sclerosis seen at Mayo Clinic, Rochester, Minn, 1990-1998

OBJECTIVE

To evaluate seizure type, electroencephalographic findings, and response to antiepileptic drug (AED) treatment in patients with multiple sclerosis (MS) and coexistent seizure activity.

PATIENTS AND METHODS

We reviewed the medical records of all patients seen at the Mayo Clinic in Rochester, Minn, with the diagnosis of MS and seizures between 1990 and 1998.

RESULTS

During the study period, 5715 patients with MS were identified. Of these 5715 patients, 51 (0.89%) experienced seizure activity. The most common ictal behavior was a generalized tonic-clonic seizure in 35 patients (68.6%). Simple or complex partial seizures occurred in 11 patients (21.6%), and 18 patients (35.3%) had only 1 seizure episode. Focal motor status epilepticus, ie, epilepsia partialis continua, occurred in 3 patients (5.9%) and was associated with cognitive impairment. In 37 patients (72.5%), the initial seizure presentation was after the diagnosis of MS. A seizure resulted in the diagnosis of MS or occurred before the diagnosis of MS but after other symptoms or signs of demyelinating disease in 14 patients (27.4%). Electroencephalography was performed in 43 patients. Electroencephalographic findings included diffuse or localized nonspecific background slowing in 19 patients (44.2%), unilateral or bilateral frontotemporal spike discharges in 9 (20.9%), generalized atypical spike-and-wave or multifocal independent epileptiform alterations in 6 (14.0%), and normal results in 11 (25.6%). Of the 45 patients who received AED therapy, 35 (77.8%) had an excellent response, ie, they were seizure free. Five treated patients (11.1%) had an intractable seizure disorder.

CONCLUSION

Most of the patients with MS who experienced seizure activity had a benign and transient disorder that was responsive to AED treatment or required no therapy.

Circadian and seasonal occurrence of subarachnoid and intracerebral hemorrhage

OBJECTIVE

To determine whether the time of onset of subarachnoid hemorrhage (SAH) or intracerebral hemorrhage (ICH) is associated with a time of day or season of year.

BACKGROUND

Prior studies have suggested that there may be a circadian and seasonal pattern of ischemic stroke occurrence, but this is less certain for hemorrhagic stroke. Population-based data have been unavailable.

METHODS

All incident ICH and SAH among residents of Rochester, MN, were ascertained. The medical records of patients were reviewed to determine the time of onset and date of occurrence. The day was divided into 8-hour periods, and the year into seasonal quartiles. Each patient was assigned a period based on the time of onset of symptoms. The data were analyzed by chi(2) analysis to determine whether there was a trend toward increased occurrence based on time period or seasonal quartile of onset.

RESULTS

From 1960 to 1989, there were 155 cases (48 men, 107 women) of incident SAH. From 1975 to 1989, there were 137 cases (57 men, 80 women) of incident ICH. There was a significant increase in the time of onset for ICH and SAH in the 8 AM to 4 PM period (p = 0.005 and p = 0.03, respectively). The concomitant occurrence of hypertension, gender, and age did not affect the time of day of occurrence. In the analysis of seasonal variation, there was a significant increase in events during December, January, and February in the combined SAH and ICH group (p = 0.032) and a trend for SAH alone (p = 0.07) but not for ICH (p = 0.34). Hypertension and age had no impact on the association between season and the occurrence of SAH and ICH.

CONCLUSION

The occurrence of SAH and ICH is increased from 8 AM to 4 PM. The occurrence of hemorrhage is increased during the winter months, but this is likely limited only to SAH.