Recruited fibroblasts reconstitute the peri-islet membrane: a longitudinal imaging study of human islet grafting and revascularisation.

AIMS/HYPOTHESIS: Rapid and adequate islet revascularisation and restoration of the islet-extracellular matrix (ECM) interaction are significant factors influencing islet survival and function of the transplanted islets in individuals with type 1 diabetes. Because the ECM encapsulating the islets is degraded during islet isolation, understanding the process of revascularisation and engraftment after transplantation is essential and needs further investigation. METHODS: Here we apply a longitudinal and high-resolution imaging approach to investigate the dynamics of the pancreatic islet engraftment process up to 11 months after transplantation. Human and mouse islet grafts were inserted into the anterior chamber of the mouse eye, using a NOD.ROSA-tomato.Rag2-/- or B6.ROSA-tomato host allowing the investigation of the expansion of host vs donor cells and the contribution of host cells to aspects such as promoting the encapsulation and vascularisation of the graft. RESULTS: A fibroblast-like stromal cell population of host origin rapidly migrates to ensheath the transplanted islet and aid in the formation of a basement membrane-like structure. Moreover, we show that the vessel network, while reconstituted by host endothelial cells, still retains the overall architecture of the donor islets. CONCLUSIONS/INTERPRETATION: In this transplantation situation the fibroblast-like stromal cells appear to take over as main producers of ECM or act as a scaffold for other ECM-producing cells to reconstitute a peri-islet-like basement membrane. This may have implications for our understanding of long-term graft rejection and for the design of novel strategies to interfere with this process.

A genetic risk score for hypertension associates with the risk of ischemic stroke in a Swedish case-control study.

Genetic risk scores (GRS), summing up the total effect of several single-nucleotide polymorphisms (SNPs) in genes associated with either coronary risk or cardiovascular risk factors, have been tested for association with ischemic stroke with conflicting results. Recently an association was found between a GRS based on 29 SNPs discovered by genome-wide association studies and hypertension. The aim of our study was to investigate the possible association of the same GRS with ischemic stroke on top of other 'traditional risk factors', also testing its potential improvement in indices of discrimination and reclassification, in a Swedish case-control study. Twenty-nine SNPs were genotyped in 3677 stroke cases and 2415 controls included in the Lund Stroke Register (LSR), the Malmö Diet and Cancer (MDC) study and the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). The analysis was conducted in the combined sample, and separately for the three studies. After adjustment for hypertension, diabetes mellitus and smoking habits, the GRS was associated with ischemic stroke in the combined sample (OR (95% CI) 1.086 (1.029-1.147) per SD increase in the GRS P=0.003) with similar trends in all three samples: LSR (1.050 (0.967-1.140); P=0.25), MDC (1.168 (1.060-1.288); P=0.002) and SAHLSIS (1.124 (0.997-1.267); P=0.055). Measures of risk discrimination and reclassification improved marginally using the GRS. A blood pressure GRS is independently associated with ischemic stroke risk in three Swedish case-control studies, however, the effect size is low and adds marginally to prediction of stroke on top of traditional risk factors including hypertension.

Variations in apolipoprotein D and sigma non-opioid intracellular receptor 1 genes with relation to risk, severity and outcome of ischemic stroke.

BACKGROUND: In experimental studies, the apolipoprotein D (APOD) and the sigma receptor type 1 (SIGMAR1) have been related to processes of brain damage, repair and plasticity. METHODS: We examined blood samples from 3081 ischemic stroke (IS) patients and 1595 control subjects regarding 10 single nucleotide polymorphisms (SNPs) in the APOD (chromosomal location 3q29) and SIGMAR1 (chromosomal location 9p13) genes to find possible associations with IS risk, IS severity (NIHSS-score) and recovery after IS (modified Rankin Scale, mRS, at 90 days). Simple/multiple logistic regression and Spearman's rho were utilized for the analyses. RESULTS: Among the SNPs analyzed, rs7659 within the APOD gene showed a possible association with stroke risk (OR = 1.12; 95% CI: 1.01-1.25; P = 0.029) and stroke severity (NIHSS ≥ 16) (OR = 0.70; 95% CI: 0.54-0.92; P = 0.009) when controlling for age, sex and vascular risk factors for stroke. No SNP showed an association with stroke recovery (mRS). CONCLUSIONS: We conclude that the SNP rs7659 within the APOD gene might be related to risk and severity of ischemic stroke in patients.

Multiplicity of risk factors in ischemic stroke patients: relations to age, sex, and subtype--a study of 2,505 patients from the lund stroke register.

BACKGROUND: The prevalence of risk factors for ischemic stroke may vary between different groups of stroke patients. We examined the distribution of individual well-established risk factors as well as the multiplicity of risk factors in different age groups and among subtypes. METHODS: In the Lund Stroke Register, we consecutively enrolled 2,505 patients with first-ever ischemic stroke from 2001 to 2009 and registered hypertension, diabetes mellitus, heart disease, current smoking, hypercholesterolemia as well as stroke subtype. RESULTS: Among young patients (<55 years), at least 50% had ≥2 risk factors and 20-25% had ≥3 risk factors. In patients aged 55 years or older, the proportion with ≥2 risk factors was 70-80% and with ≥3 risk factors 35-45%. Men and women had a similar burden of risk factors. Approximately 50% of the cases classified as cardioembolism (CE) and large artery atherosclerosis (LAA) had ≥3 risk factors, which was significantly more than the other TOAST (Trial of Org 10172 in Acute Stroke Treatment) subtypes (CE p < 0.001, LAA p = 0.001). CONCLUSIONS: The prevalence of well-established risk factors is similar among young and old stroke patients with large proportions (50-80%) having ≥2 risk factors. Even though the prevalence of well-established risk factors differs between pathogenetic subtypes, these risk factors as well as the multiplicity of risk factors seem to be of clinical importance in all major subtypes of ischemic stroke.

Genetic variation within the interleukin-1 gene cluster and ischemic stroke.

BACKGROUND AND PURPOSE: Evidence is emerging that inflammation plays a key role in the pathophysiology of ischemic stroke (IS). The aim of this study was to investigate whether genetic variation in the interleukin-1α, interleukin-1ß, and interleukin-1 receptor antagonist genes (IL1A, IL1B, and IL1RN) is associated with IS and/or any etiologic subtype of IS. METHODS: Twelve tagSNPs were analyzed in the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), which comprises 844 patients with IS and 668 control subjects. IS subtypes were defined according to the Trial of Org 10172 in Acute Stroke Treatment criteria in SAHLSIS. The Lund Stroke Register and the Malmö Diet and Cancer study were used as a replication sample for overall IS (in total 3145 patients and 1793 control subjects). RESULTS: The single nucleotide polymorphism rs380092 in IL1RN showed an association with overall IS in SAHLSIS (OR, 1.21; 95% CI, 1.02-1.43; P=0.03), which was replicated in the Lund Stroke Register and the Malmö Diet and Cancer study sample. An association was also detected in all samples combined (OR, 1.12; 95% CI, 1.04-1.21; P=0.03). Three single nucleotide polymorphisms in IL1RN (including rs380092) were nominally associated with the subtype of cryptogenic stroke in SAHLSIS, but the statistical significance did not remain after correction for multiple testing. Furthermore, increased plasma levels of interleukin-1 receptor antagonist were observed in the subtype of cryptogenic stroke compared with controls. CONCLUSIONS: This comprehensive study, based on a tagSNP approach and replication, presents support for the role of IL1RN in overall IS.

A common missense variant in the ATP receptor P2X7 is associated with reduced risk of cardiovascular events.

BACKGROUND AND PURPOSE: Extracellular adenosine triphosphate (ATP) regulates inflammatory cells by activation of the P2X(7) receptor. We hypothesized that polymorphisms in P2RX7 influence the risk of ischemic heart disease (IHD), ischemic stroke (IS) and cardiovascular risk factors and tested this hypothesis using genetic association studies. METHODS: Two loss-of-function SNPs in P2RX7 were genotyped in 1244 IHD cases and 2488 controls as well as 5969 individuals with cardiovascular risk factors. Eleven SNPs in a 250 kb region on chromosome 12 spanning P2RX7 as well as neighboring genes OASL, P2RX4 and CAMKK2 were genotyped in 4138 individuals with IS and 2528 controls. Association was examined using linear and logistic regression models with an additive genetic model. RESULTS: The common loss-of-function variant rs3751143 was significantly associated with a decreased risk of IHD in smokers (P = 0.03) as well as decreased risk of IS (OR 0.89; 95% CI = 0.81-0.97; P = 0.012). In addition, an intronic SNP in CAMKK2, rs2686342, were associated with a decreased risk of IS (OR 0.89; 95% CI = 0.82-0.97; P = 0.011). In subgroup analyses, both SNPs were associated with decreased risk of IS in individuals with hypertension (P = 0.045 and 0.015, respectively). CONCLUSIONS: A common loss-of-function missense variant in the gene encoding the P2X(7) receptor is associated with reduced risk of IS and with IHD in smokers. These findings might implicate a role of purinergic signaling in atherogenesis or atherothrombosis.

A large-sample assessment of possible association between ischaemic stroke and rs12188950 in the PDE4D gene.

Previous reports have shown ambiguous findings regarding the possible associations between ischaemic stroke (IS) and single nucleotide polymorphisms (SNPs) in the phosphodiesterase 4D (PDE4D) gene region. The SNP rs12188950 (or SNP45) has often been studied in this context. We performed a multi-centre study involving a large sample of 2599 IS patients and 2093 control subjects from the south and west regions of Sweden to replicate previous studies regarding IS risk and rs12188950. Subjects from Lund Stroke Register (LSR), Malmö Diet and Cancer Study (MDC) and Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS) were enroled. Subgroups of participants with hypertension and participants <55 years of age, as well as the TOAST subgroups large vessel disease, small vessel disease and cardioembolism, were also assessed. Univariate odds ratios (ORs) and ORs controlling for hypertension, diabetes and current smoking were calculated. We additionally performed a meta-analysis including 10,500 patients and 10,102 control subjects from 17 publications (including the present study). When assessing pooled data from LSR, MDC and SAHLSIS we obtained no association between IS and rs12188950 for all participants (OR=0.93; 95% confidence interval (CI): 0.83-1.05). Significant associations were not found for hypertensive participants or participants with age <55, or when separately evaluating patients from the three different TOAST subgroups. The meta-analysis showed no significant overall estimate (OR=0.96; 95% CI: 0.89-1.04) with significant heterogeneity for random effect (P=0.042). No effect from rs12188950 on IS was found from either our pooled multi-centre data or the performed meta-analysis. We did not find any association between the examined subgroups and rs12188950 either.

Genetic variants in serum and glucocortocoid regulated kinase 1, a regulator of the epithelial sodium channel, are associated with ischaemic stroke.

OBJECTIVE: Serum and glucocorticoid regulated kinase 1 (SGK1) expression is increased by aldosterone and is a key regulator of the amiloride-sensitive sodium channel (ENaC) in the distal nephron. We have previously shown that two SNPs in SGK1 (rs1057293 and rs1743966) are associated with blood pressure variation and blood pressure progression in the general population. Therefore, we tested the association of these variants with ischaemic stroke. METHODS: Using logistic regression, we analysed rs1057293 and rs1743966 for association with ischaemic stroke in two independent age-matched and sex-matched case-control groups from the twin cities of Lund (cases n=1837 and controls n=947) and Malmö (cases n=888 and controls n=893) in the Scania region of southern Sweden. RESULTS: In additive models adjusted for hypertension, smoking and diabetes, the major allele (G) of rs1057293 was associated (odds ratio, 95% confidence interval; P value) with ischaemic stroke with similar effect size in both studies; in Lund (1.35, 1.11-1.64; P=0.002) and Malmö (1.30, 1.03-1.65; P=0.027). When the two studies were pooled, the overall association was 1.32, 1.14-1.52; P<0.001. The major allele of rs1743966 (A), which was in linkage disequilibrium with rs1057293, showed a similar trend as rs1057293 G-allele but with slightly weaker effect size and P value. CONCLUSION: In two independent but ethnically similar populations, we observed an association between genetic variants in SGK1 and ischaemic stroke. Interestingly, the association seems to be at least partially independent of blood pressure. This could imply that cerebrovascular ENaC or other SGK1-regulated proteins may be of importance for development of ischaemic stroke.

Genetic variant on chromosome 12p13 does not show association to ischemic stroke in 3 Swedish case-control studies.

BACKGROUND AND PURPOSE: in a genome-wide association study and subsequent case-control studies, the single-nucleotide polymorphism rs12425791 on chromosome 12p13 was reported to be associated with ischemic stroke, but this could not be validated in a recent well-powered study. We therefore investigated whether an association between ischemic stroke and rs12425791 could be detected in 3 different case-control studies from the southwest of Sweden. METHODS: we examined 3606 patients with ischemic stroke and 2528 controls from 3 independent case-controls studies. RESULTS: no significant association between ischemic stroke and the single-nucleotide polymorphism rs12425791 was detected in any of the 3 case-control samples or in the samples combined. The odds ratio for ischemic stroke for the minor allele in the combined sample was 1.02 (95% CI, 0.93 to 1.13). CONCLUSIONS: the single-nucleotide polymorphism rs12425791 does not confer a substantial risk for ischemic stroke in our population. Our results support a recent large study including other European populations.

Common genetic variants on chromosome 9p21 confers risk of ischemic stroke: a large-scale genetic association study.

BACKGROUND: Epidemiological studies indicate a genetic contribution to ischemic stroke risk, but specific genetic variants remain unknown, with the exception of a few rare variants. Recent genome-wide association studies identified and replicated common genetic variants on chromosome 9p21 to confer risk of coronary heart disease. We examined whether these variants are associated with ischemic stroke. METHODS AND RESULTS: We genotyped 6 common genetic variants on chromosome 9p21, previously associated with coronary artery disease in genome-wide association studies, in 2 population-based studies in southern Sweden, the Lund Stroke Register (n=1837 cases, 947 controls) and the Malmö Diet and Cancer study (MDC; n=888 cases, 893 controls). We examined association in each study and in the pooled dataset. Adjustments were made for cardiovascular risk factors and further for previous myocardial infarction in MDC. We found a modest increase in ischemic stroke risk for 2 common (minor allele frequencies 0.46 to 0.49) variants, rs2383207 (P=0.04 in Lund Stroke Register, P=0.01 in MDC) and rs10757274 (P=0.03 in Lund Stroke Register, P=0.03 in MDC), in each sample independently. The strength of the association increased when samples were pooled with an odds ratio of 1.15 (95% CI, 1.05 to 1.25; P=0.002) for the strongest variant rs2383207. Results were similar after adjustment for clinical covariates. rs1333049 also showed significant association in MDC, which increased in the pooled sample (P=0.004). CONCLUSIONS: In this large sample (n=4565), we detected common genetic determinants for ischemic stroke on chromosome 9p21. Our findings indicate that ischemic stroke shares pathophysiological determinants with coronary heart disease and other arterial diseases and highlight the need for large sample sizes in stroke genetics.

Sonographic visualization of the rectoanal inhibitory reflex in children suspected of having Hirschsprung disease: a pilot study.

OBJECTIVE: To date, for detection of the absence of peristalsis in children with chronic constipation and a suspicion of Hirschsprung disease (HD), children have been investigated with a contrast enema. If the radiographic investigation is inconclusive, anometry and a rectal biopsy are performed. A new noninvasive real-time sonographic method for examination of the rectoanal inhibitory reflex (RAIR) was compared with anometry. METHODS: The rectum and anal canal of children were visualized transperineally on sonography. The RAIR was elicited by injecting water into the rectum, and the events in the bowel were recorded on video for offline analysis. RESULTS: Injection of water initiated a peristaltic wave that moved the rectal contents into the proximal part of the anal canal in healthy children. Among 28 children with suspected HD, 3 showed aganglionosis in their biopsy samples. These 3 children lacked the RAIR according to both sonography and anometry. Both methods had a negative predictive value of 100%. In 17 children, the RAIR was present according to both sonography and anometry, and all of these children had normal histologic findings. In 8 children, sonography did not show the reflex despite normal histologic findings; in 2 of these, the quality of the investigation made the evaluation uncertain. CONCLUSIONS: This pilot study indicates that in children with chronic constipation, a transperineal sonographic examination of the RAIR is comparable to anometry and can facilitate the diagnose of HD.

Ischaemic stroke in hypertensive patients is associated with variations in the PDE4D genome region.

Previous Icelandic studies reported that single nucleotide polymorphisms (SNPs) in the phosphodiesterase 4D (PDE4D) region and the 5-lipoxygenase activating protein ALOX5AP were associated with ischaemic stroke, whereas other studies reported ambiguous findings. We examined 932 ischaemic stroke patients from a Swedish population-based stroke register, and 396 control subjects. We assessed possible associations between ischaemic stroke and nine preselected SNPs in the chromosome regions of the PDE4D gene, including rs12188950 (SNP45) and rs3887175 (SNP39); the ALOX5AP gene, including rs17222814 (SG13S25) and the promoter region of the MHC class II transactivator, MHC2TA. The T allele of SNP45 showed negative association with ischaemic stroke (odds ratio, OR=0.72; 95% confidence interval (CI): 0.58-0.91; P=0.0055). Among hypertensive subjects, this influence of the T allele of SNP45, and the T allele of SNP39, were more pronounced (with OR=0.52; 95% CI: 0.37-0.73; P=0.0001 and OR=0.57; 95% CI: 0.41-0.79; P=0.0007, respectively). These SNPs also interacted with hypertension with a relative excess risk due to interaction of -1.66 (P=0.0002) for SNP45 and -1.65 (P=0.0005) for SNP39. The P-values remained significant after correction for multiple testing. Among nonhypertensives, the A allele of SG13S25 indicated increased stroke risk (OR=1.82; 95% CI: 1.21-2.74; P=0.0039; not significant after Bonferroni correction). SNP45 was associated with ischaemic stroke even when controlling for hypertension, diabetes, heart disease and smoking. Our meta-analysis of 13 studies (including ours) showed no overall influence of SNP45 on ischaemic stroke. However, the 13 studies may differ because of nonrandom causes, as suggested by the heterogeneity test (P=0.042). This might support previously undetected mechanisms causing fluctuating ischaemic stroke risk.

Road traffic noise in southern Sweden and its relation to annoyance, disturbance of daily activities and health.

OBJECTIVES: This study investigated residential noise from road traffic and its relation to annoyance, disturbance of daily activities, and general health. METHODS: A large public health survey in southern Sweden in 1999-2000 supplied data (N=13 557; 54% participation rate) on the demography, annoyance, and disturbance of daily activities, and on general health problems regarding concentration, sleep, stress, and treatment for hypertension. Residential road noise exposure was assessed with a geographic information system. Associations with 24-hour equivalent (average) and maximum road noise level were investigated for all participants and for selected subgroups using the Cochran-Armitage trend test and Cox regression analysis. RESULTS: Annoyance from road traffic noise and the disturbance of daily activities increased markedly with road noise exposure. More than 25% reported at least occasional disturbance from traffic noise during relaxation and sleep in the highest exposure category for each noise measure. No overall pattern between road noise exposure and general health problems emerged. Among the participants that reported annoyance from road traffic noise (N=623), the average road noise level was associated with concentration problems (P for trend = 0.03) and with treatment for hypertension (P for trend = 0.02). Positive associations between average road noise exposure and health problems were found among females (hypertension), persons born outside Sweden (sleep), the unemployed (stress), and participants that reported financial problems (concentration problems). CONCLUSIONS: Exposure to road traffic noise at high levels was common and produced frequent disturbances of daily activities. Negative health effects from road traffic noise were observed in important subgroups. The findings are of concern for southern Sweden, as well as for other regions with similar or higher traffic intensity.

Complications of video-assisted gastrostomy in children with malignancies or neurological diseases.

AIM: To test the hypothesis whether the administration of cytostatic drugs close to surgery in children with malignancies influences the rate of postoperative complications. METHOD: Included in the study were 27 children with malignancies and a control group of 27 neurologically impaired children. All the children had nutritional problems and underwent a video-assisted gastrostomy (VAG) operation during the period 1997-2002. The children were postoperatively followed up. All complications were documented according to a protocol by a specially trained nurse and correlated to the time elapsed from completion of the last preoperative or the first postoperative cytostatic drug treatment. The complications in the two groups were compared. RESULTS: The children with malignant diseases did not have more postoperative complications of the VAG than those having neurological defects. There was no correlation to complications regarding timing of the operation and administration of cytostatic drugs. CONCLUSION: This study revealed no aggravated influence of cytostatic drug treatment on early postoperative problems of VAG. The timing of cytostatic drug administration in relation to the surgical intervention did not influence the frequency of postoperative complications.

Prevalence of stroke and vascular risk factors among first-degree relatives of stroke patients and control subjects. A prospective consecutive study.

BACKGROUND: Genetic and environmental factors may be of importance for stroke risk. We assessed the prevalence of stroke and vascular risk factors among first-degree relatives and spouses of stroke patients and control subjects. METHODS: As a part of the Lund Stroke Register study, we asked 925 consecutive patients with first-ever stroke and 286 control subjects to complete a questionnaire about all their first-degree relatives and spouses. The questionnaires addressed whether these relatives had been affected by stroke or TIA, hypertension, heart disease, diabetes mellitus, and if they were smokers. RESULTS: A total of 606 patients and 261 control subjects returned the questionnaire, providing information on 4,972 first-degree relatives and 738 spouses. The prevalence of stroke or TIA was 12.3% among first-degree relatives of patients and 7.5% among first-degree relatives of control subjects (OR 1.74, 95% CI 1.36-2.22). Corresponding results for hypertension were 21.0 and 16.7% (OR 1.33, 95% CI 1.10-1.60). The prevalences of heart disease, diabetes mellitus and smoking did not differ significantly between first-degree relatives of patients and control subjects. Spouses of patients and control subjects had similar prevalences of stroke or TIA and vascular risk factors. CONCLUSIONS: The prevalences of stroke or TIA and hypertension are higher among first-degree relatives of stroke patients than among first-degree relatives of control subjects. This, and the lack of differences between spouses of patients and control subjects, indicates that an increased risk of stroke may in part be explained by heritability of hypertension.