| 1. |
- Mishra, A., et al.
(författare)
-
Stroke genetics informs drug discovery and risk prediction across ancestries
- 2022
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 611
-
Tidskriftsartikel (refereegranskat)abstract
- Previous genome-wide association studies (GWASs) of stroke - the second leading cause of death worldwide - were conducted predominantly in populations of European ancestry(1,2). Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis(3), and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach(4), we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry(5). Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries.
|
|
| 2. |
|
|
| 3. |
- Olafsson, S, et al.
(författare)
-
Fourteen sequence variants that associate with multiple sclerosis discovered by meta-analysis informed by genetic correlations
- 2017
-
Ingår i: NPJ genomic medicine. - : Springer Science and Business Media LLC. - 2056-7944. ; 2, s. 24-
-
Tidskriftsartikel (refereegranskat)abstract
- A meta-analysis of publicly available summary statistics on multiple sclerosis combined with three Nordic multiple sclerosis cohorts (21,079 cases, 371,198 controls) revealed seven sequence variants associating with multiple sclerosis, not reported previously. Using polygenic risk scores based on public summary statistics of variants outside the major histocompatibility complex region we quantified genetic overlap between common autoimmune diseases in Icelanders and identified disease clusters characterized by autoantibody presence/absence. As multiple sclerosis-polygenic risk scores captures the risk of primary biliary cirrhosis and vice versa (P = 1.6 × 10−7, 4.3 × 10−9) we used primary biliary cirrhosis as a proxy-phenotype for multiple sclerosis, the idea being that variants conferring risk of primary biliary cirrhosis have a prior probability of conferring risk of multiple sclerosis. We tested 255 variants forming the primary biliary cirrhosis-polygenic risk score and found seven multiple sclerosis-associating variants not correlated with any previously established multiple sclerosis variants. Most of the variants discovered are close to or within immune-related genes. One is a low-frequency missense variant in TYK2, another is a missense variant in MTHFR that reduces the function of the encoded enzyme affecting methionine metabolism, reported to be dysregulated in multiple sclerosis brain.
|
|
| 4. |
- Keyak, J. H., et al.
(författare)
-
Effect of finite element model loading condition on fracture risk assessment in men and women: The AGES-Reykjavik study
- 2013
-
Ingår i: Bone. - : Elsevier BV. - 1873-2763 .- 8756-3282. ; 57:1, s. 18-29
-
Tidskriftsartikel (refereegranskat)abstract
- Proximal femoral (hip) strength computed by subject-specific CT scan-based finite element (FE) models has been explored as an improved measure for identifying subjects at risk of hip fracture. However, to our knowledge, no published study has reported the effect of loading condition on the association between incident hip fracture and hip strength. In the present study, we performed a nested age- and sex-matched case-control study in the Age Gene/Environment Susceptibility (AGES) Reykjavik cohort Baseline (pre-fracture) quantitative CT (QCT) scans of 5500 older male and female subjects were obtained. During 4-7 years follow-up, 51 men and 77 women sustained hip fractures. Ninety-seven men and 152 women were randomly selected as controls from a pool of age- and sex-matched subjects. From the QCT data, FE models employing nonlinear material properties computed FE-strength of the left hip of each subject in loading from a fall onto the posterolateral (F-PL), posterior (F-P) and lateral (F-L) aspects of the greater trochanter (patent pending). For comparison, FE strength in stance loading (F-Stance) and total femur areal bone mineral density (aBMD) were also computed. For all loading conditions, the reductions in strength associated with fracture in men were more than twice those in women (p <= 0.01). For fall loading specifically, posterolateral loading in men and posterior loading in women were most strongly associated with incident hip fracture. After adjusting for aBMD, the association between F-P and fracture in women fell short of statistical significance (p = 0.08), indicating that FE strength provides little advantage over aBMD for identifying female hip fracture subjects. However, in men, after controlling for aBMD, F-PL was 424 N (11%) less in subjects with fractures than in controls (p = 0.003). Thus, in men, FE models of posterolateral loading include information about incident hip fracture beyond that in aBMD. (c) 2013 Elsevier Inc. All rights reserved.
|
|
| 5. |
- Keyak, J. H., et al.
(författare)
-
Male-female differences in the association between incident hip fracture and proximal femoral strength: A finite element analysis study
- 2011
-
Ingår i: Bone. - : Elsevier BV. - 1873-2763 .- 8756-3282. ; 48:6, s. 1239-1245
-
Tidskriftsartikel (refereegranskat)abstract
- Hip fracture risk is usually evaluated using dual energy X-ray absorptiometry (DXA) or quantitative computed tomography (QCT) which provide surrogate measures for proximal femoral strength. However, proximal femoral strength can best be estimated explicitly by combining QCT with finite element (FE) analysis. To evaluate this technique for predicting hip fracture in older men and women, we performed a nested age- and sex-matched case-control study in the Age Gene/Environment Susceptibility (AGES) Reykjavik cohort. Baseline (pre-fracture) QCT scans of 5500 subjects were obtained. During 4-7 years follow-up, 51 men and 77 women sustained hip fractures. Ninety-seven men and 152 women were randomly selected as age- and sex-matched controls. FE-strength of the left hip of each subject for stance (F-Stance) and posterolateral fall (F-Fall) loading, and total femur areal bone mineral density (aBMD) were computed from the QCT data. F-Stance and F-Fall in incident hip fracture subjects were 13%-25% less than in control subjects (p <= 0.006) after controlling for demographic parameters. The difference between FE strengths of fracture and control subjects was disproportionately greater ill men (stance, 22%; fall, 25%) than in women (stance, 13%; fall, 18%) (p <= 0.033), considering that Fstar,ce and FFall in fracture subjects were greater in men than in women ( p < 0.001). For men, F-Stance was associated with hip fracture after accounting for aBMD (p = 0.013). These data indicate that F-Stance provides information about fracture risk that is beyond that provided by aBMD (p = 0.013). These findings support further exploration of possible sex differences in the predictors of hip fracture and of sex-specific strategies for using FE analysis to manage osteoporosis. (C) 2011 Elsevier Inc. All rights reserved.
|
|
| 6. |
|
|
| 7. |
- Lang, T. F., et al.
(författare)
-
Age-related loss of proximal femoral strength in elderly men and women: The Age Gene/Environment Susceptibility Study - Reykjavik
- 2012
-
Ingår i: Bone. - : Elsevier BV. - 1873-2763 .- 8756-3282. ; 50:3, s. 743-748
-
Tidskriftsartikel (refereegranskat)abstract
- The risk of hip fracture rises rapidly with age, and is particularly high in women. This increase in fracture risk reflects both the age-related change in the risk of falling and decrements in the strength of the proximal femur. To better understand the extent to which proximal femoral density, structure and strength change with age as a function of gender, we have carried out a longitudinal analysis of proximal femoral volumetric quantitative computed tomographic (vQCT) images in men and women, analyzing changes in trabecular and cortical bone properties, and using subject-specific finite element modeling (FEM) to estimate changes in bone strength. In the AGES-Reykjavik Study vQCT scans of the hip were performed at a baseline visit in 2002-2006 and at a second visit 5.05 +/- 0.25 years later. From these, 223 subjects (111 men, 112 women, aged 68-87 years) were randomly selected. The subjects were evaluated for longitudinal changes in three bone variables assessed in a region similar to the total femur region quantified by DXA: areal bone mineral density (aBMD), trabecular volumetric bone mineral density (tBMD) and the ratio of cortical to total tissue volume (cvol/ivol). They were also evaluated for changes in bone strength using FEM models of the left proximal femur. Models were analyzed under single-limb stance loading (F-Stance), which approximates normal physiologic loading of the hip, as well as a load approximating a fall onto the posterolateral aspect of the greater trochanter (F-Fall). We computed five-year absolute and percentage changes in aBmD, tBMD, cvol/ivol, F-Fall and F-Stance. The Mann-Whitney Test was employed to compare changes in bone variables between genders and the Wilcoxon Signed Rank Test was used to compare changes in bone strength between loading conditions. Multiple (linear) regression was employed to determine the association of changes in F-Fall and F-Stance with baseline age and five-year weight loss. Both men and women showed declines in indices of proximal femoral density and structure (aBMD: men -3.9 +/- 6.0%, women -6.1 +/- 6.2%; tBMD: men -14.8 +/- 20.3%, women -23.9 +/- 26.8%; cvol/ivol: men -2.6 +/- 4.6%, women -4.7 +/- 4.8%, gender difference: p<0.001). Both men and women lost bone strength in each loading condition (F-Stance: men -4.2 +/- 9.9%, women -8.3 +/- 8.5%; F-Fall: men -7.0 +/- 15.7%, women -12.8 +/- 13.2%; all changes from baseline p<0.0001). The gender difference in bone strength loss was statistically significant in both loading conditions (p<0.001 for F-Stance and P<0.01 for F-Fall) and F-Fall, was lost at a higher rate than F-Stance in men (p<0.01) and women (p<0.0001). The gender difference in strength loss was statistically significant after adjustment for baseline age and weight loss in both loading conditions (p<0.01). In these multi-linear models, men showed increasing rates of bone loss with increasing age (F-Fall: p=0.002; F-Stance; p=0.03), and women showed increasing bone strength loss with higher degrees of weight loss (F-Stance: p=0.003). The higher loss of F-Fall compared to F-Stance supports previous findings in animal and human studies that the sub-volumes of bone stressed under normal physiologic loading are relatively better protected in aging. The gender difference in hip bone strength loss is consistent with the higher incidence of hip fractureamong elderly women. (C) 2011 Elsevier Inc. All rights reserved.
|
|
| 8. |
- Qiu, C, et al.
(författare)
-
Cerebral microbleeds, retinopathy, and dementia : the AGES-Reykjavik Study
- 2010
-
Ingår i: Neurology. - 0028-3878 .- 1526-632X. ; 75:24, s. 2221-8
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine whether microvascular damage, indicated by cerebral microbleeds (CMBs) and retinal microvascular signs, is associated with cognitive function and dementia in older persons.METHODS: This is a cross-sectional study of 3,906 participants (mean age 76 years; 58% women) in the AGES-Reykjavik Study (2002-2006). We assessed CMBs on MRI and retinal microvascular signs on digital retinal images. Composite Z scores of memory, processing speed, and executive function were derived from a battery of neurocognitive tests. Dementia and subtypes were diagnosed following international criteria. Regression models were used to relate cognitive Z scores and dementia to CMBs and retinal microvascular signs, adjusting for demographics, cardiovascular factors, and brain ischemic lesions.RESULTS: People with multiple (≥ 2) CMBs had lower Z scores on tests of processing speed (β-coefficient -0.16; 95% confidence interval -0.26 to -0.05) and executive function (-0.14; -0.24 to -0.04); results were strongest for having multiple CMBs located in the deep hemispheric or infratentorial areas. The odds ratio of vascular dementia was 2.32 (95% confidence interval 1.02 to 5.25) for multiple CMBs and 1.95 (1.04 to 3.62) for retinopathy. Having both CMBs and retinopathy, compared to having neither, was significantly associated with markedly slower processing speed (-0.25; -0.37 to -0.12), poorer executive function (-0.19; -0.31 to -0.07), and an increased odds ratio of vascular dementia (3.10; 1.11 to 8.62).CONCLUSION: Having multiple CMBs or concomitant CMBs and retinopathy is associated with a profile of vascular cognitive impairment. These findings suggest that microvascular damage, as indicated by CMBs and retinopathy lesions, has functional consequences in older men and women living in the community.
|
|
| 9. |
|
|
| 10. |
- Sigurdsson, S B, et al.
(författare)
-
Responses to ions and vasoconstrictor agents and changes of potassium fluxes in vascular smooth muscle during hypoxia
- 1981
-
Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 112:4, s. 455-462
-
Tidskriftsartikel (refereegranskat)abstract
- An inhibitory effect of hypoxia (Po2 less than 5 mmHg) on electrical and mechanical activity of the smooth muscle of the rat portal vein has been described by Hellstrand, Johansson & Norberg (1977). The present study using the sucrose gap method confirmed their finding that spontaneous activity was completely (or almost completely) abolished by the low Po2. Increased [K+]0 from 6 to 24 mM or decreased [Na+]0 from 137.5 to 76.5 mM reinitiated electrical and mechanical activity during hypoxia. If muscle activity had already been increased by 24 mM K+ or 76.5 mM Na+ solutions in the aerobic situation, switching to hypoxia caused only partial inhibition. In hypoxic solutions of such altered ionic composition a gradual increase in muscle activity with time was seen especially in the low Na+-solution. Stimulating agents such as noradrenaline, acetylcholine, 4-aminopyridine, and Ba2+ could reinitiate spike activity and contractions under hypoxic conditions. Ouabain stimulated the activity in normoxia but no effect was seen in hypoxia. Uptake and washout of 42K+ was studied. No difference in uptake was found between normoxic and hypoxic conditions. The rate of 42K+ efflux was decreased under hypoxia. A similar decrease was produced by Mn2+ (0.4 mM) which, like hypoxia abolished phasic muscle activity. In both cases the reduction in 42K+ efflux may just reflect the elimination of action potentials. It is concluded from these results that profound hypoxia exerts its inhibitory effect on the smooth muscle to a large extent through membrane mechanisms responsible for pacemaker activity or spike generation. The electrophysiological response may be secondary to change in intracellular [Na+] or [Ca2+].
|
|
