Increased progression of carotid intima media thickness in thyroid peroxidase antibodies-positive rheumatoid arthritis patients

Deciphering thyroid function and CIMT: a Mendelian randomization study of the U-shaped influence mediated by apolipoproteins

Background

Carotid Intima-Media Thickness (CIMT) is a key marker for atherosclerosis, with its modulation being crucial for cardiovascular disease (CVD) risk assessment. While thyroid function's impact on cardiovascular health is recognized, the causal relationship and underlying mechanisms influencing CIMT remain to be elucidated.

Methods

In this study, Mendelian Randomization (MR) was employed to assess the causal relationship between thyroid function and CIMT. Thyroid hormone data were sourced from the Thyroidomics Consortium, while lipid traits and CIMT measurements were obtained from the UK Biobank. The primary analysis method was a two-sample MR using multiplicative random effects inverse variance weighting (IVW-MRE). Additionally, the study explored the influence of thyroid hormones on lipid profiles and assessed their potential mediating role in the thyroid function-CIMT relationship through multivariate MR analysis.

Results

The study revealed that lower levels of Free Thyroxine (FT4) within the normal range are significantly associated with increased CIMT. This association was not observed with free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), or TPOAb. Additionally, mediation analysis suggested that apolipoprotein A-I and B are involved in the relationship between thyroid function and CIMT. The findings indicate a potential U-shaped curve relationship between FT4 levels and CIMT, with thyroid hormone supplementation in hypothyroid patients showing benefits in reducing CIMT.

Conclusion

This research establishes a causal link between thyroid function and CIMT using MR methods, underscoring the importance of monitoring thyroid function for early cardiovascular risk assessment. The results advocate for the consideration of thyroid hormone supplementation in hypothyroid patients as a strategy to mitigate the risk of carotid atherosclerosis. These insights pave the way for more targeted approaches in managing patients with thyroid dysfunction to prevent cardiovascular complications.

Normal Anti-Thyroid Peroxidase Antibody (TPO-Ab) Titers and Active Arterial Wall Thickening among Euthyroid Individuals: A Prospective Study

Among euthyroid individuals, having an anti-thyroid peroxidase antibody (TPO-Ab) titer in the normal range (negative) is positively associated with atherosclerosis as evaluated based on carotid intima-media thickness (CIMT). Atherosclerosis is an established risk factor for cardiovascular disease, but no significant association between yearly progression in CIMT and cardiovascular disease has been reported. Therefore, clarifying the association between having a TPO-Ab titer in the normal range and yearly progression in CIMT (i.e., active arterial wall thickening) among euthyroid individuals could help inform strategies for preventing cardiovascular disease. We conducted a prospective study of 1069 Japanese subjects with free triiodothyronine and free thyroxine levels within the normal range. Having a TPO-Ab titer in the normal range was significantly positively associated with baseline atherosclerosis and significantly inversely associated with active arterial wall thickening. After adjusting for known confounding factors, the adjusted odds ratio (OR) and 95% confidence interval (CI) of log (TPO-Ab titer) for baseline atherosclerosis and active arterial wall thickening was 2.16 (1.07, 4.35) and 0.59 (0.37, 0.93), respectively. Since progression in CIMT is a process of aggressive endothelial repair, deficient endothelial repair inhibits active arterial wall thickening. Therefore, high–normal TPO-Ab titers might induce a deficiency in endothelial repair.

Autoimmune thyroid disorders and rheumatoid arthritis: A bidirectional interplay

Rheumatoid arthritis (RA) and autoimmune thyroid disease (AITD) can occur in the same patient in the autoimmune polyglandular syndrome 2. The association of the two conditions has been recognized long-time ago and the prevalence of AITD in patients with RA and vice versa is well assessed. Geographical variation of AITD and related autoantibodies in RA patients is partly due to ethnic and environmental differences of the studied populations. The impacts of thyroid disorders on RA outcome and vice versa are still controversy. In both AITD and RA genetic susceptibility and environmental factors play a synergic role in the development of the diseases. In this review we aimed at investigating the association of AITD and thyroid autoantibodies with RA, the common pathogenic pathways, the correlation with RA disease activity, and influence of the treatment.

TPO-Ab plays a role in arterial remodeling in patients with intracranial stenosis

BACKGROUND AND AIMS

Intracranial stenosis (ICS), the common cause of ischemic stroke worldwide, is associated with a high risk of recurrent stroke. We aimed to investigate the relationship between arterial remodeling and antithyroid peroxidase-antibody (TPO-Ab) level in ICS and the effect of TPO-Ab level on the migration of vascular smooth muscle cells (VSMCs).

METHODS

We analyzed data of mild-to-severe ICS patients with normal thyroid function who underwent high-resolution magnetic resonance imaging in our center. Vessel area (VA), lumen area, wall area and plaque size were assessed at the most narrowed lumen (MNL) and reference site, respectively. The remodeling index (RI) was defined as VAMNL/VAreference. Negative remodeling (NR) or non-NR was defined as RI ≤ 0.95 or > 0.95. A scratch-wound healing assay was also designed to analyze the impact of TPO-Ab level on migration of VSMCs, which were isolated from thoracic aorta segments of Sprague Dawley rats.

RESULTS

A total of 88 patients were included. Patients with elevated TPO-Ab had smaller VA, wall area, plaque size and RI than those with normal level (p < 0.05). Elevated TPO-Ab was significantly associated with NR after adjusting for demographic and vascular risks (odds ratio 10.629, 95% confidence interval, 1.842-61.327, p = 0.008). The rate of VSMCs migration was significantly increased after culture with TPO-Ab (TPO-Ab 1 μg/ml vs. Mock, 29.8% vs. 12.0%, p < 0.01).

CONCLUSIONS

Elevated TPO-Ab in ICS patients was related to NR. TPO-Ab could promote VSMCs migration, which might be involved in the NR of intracranial artery.

Prevalence of thyroid autoantibodies in patients with systematic autoimmune rheumatic diseases. Cross-sectional study

BACKGROUND

Thyroid autoimmunity is more common in patients with rheumatic diseases than in healthy populations. The degree of association seems subject to influence from patients' geographical location. Here, we aimed to ascertain the prevalence of thyroid autoantibodies in a cohort of patients with systemic rheumatic disease and the degree of association between its presence and inflammatory activity.

DESIGN AND SETTING

Cross-sectional observational study in a rheumatology unit.

METHODS

301 patients with systemic lupus erythematosus (SLE), 210 with rheumatoid arthritis (RA), 58 with scleroderma (SSc) and 80 with spondyloarthritis (SpA) were studied regarding thyroid function (TSH and T4), anti-thyroglobulin (TgAb) and anti-thyroperoxidase (TPOab) and compared with 141 healthy controls. Disease activity in patients with rheumatic disease was assessed through appropriate indexes.

RESULTS

There were more antithyroid antibodies in SLE patients with hypothyroidism (P = 0.01; odds ratio, OR 2.7; 95% confidence interval, CI: 1.20-6.26) and in those without hypothyroidism (P = 0.06; OR 2.4; 95% CI: 1.28-4.55) than in controls. SSc patients also showed: P = 0.03 both with antithyroid antibodies and hypothyroidism (OR 3.4; 95% CI: 1.06-10.80) and without hypothyroidism (OR 3.1; 95% CI: 1.11-0.13). RA and SpA patients had the same prevalence as controls (P not significant). Presence of autoantibodies with and without hypothyroidism was not associated with the activity or functional indexes evaluated.

CONCLUSION

SLE and SSc were associated with higher prevalence of thyroid autoantibodies in patients with and without hypothyroidism, unlike SpA and RA. There was no link between thyroid autoantibody presence and disease activity or functional impairment.

Recent advances in understanding autoimmune thyroid disease: the tallest tree in the forest of polyautoimmunity

Autoimmune thyroid disease (AITD) is often observed together with other autoimmune diseases. The coexistence of two or more autoimmune diseases in the same patient is referred to as polyautoimmunity, and AITD is the autoimmune disease most frequently involved. The occurrence of polyautoimmunity has led to the hypothesis that the affected patients suffer from a generalized dysregulation of their immune system. The present review summarizes recent discoveries unravelling the immunological mechanisms involved in autoimmunity, ranging from natural autoimmunity to disease-specific autoimmunity. Furthermore, the clinical grounds for considering AITD in a setting of polyautoimmunity are explored. A better understanding of these may pave the way for designing new treatment modalities targeting the underlying immune dysregulation when AITD appears in the context of polyautoimmunity.

Thyroid function and ischemic heart disease: a Mendelian randomization study

To clarify the role of thyroid function in ischemic heart disease (IHD) we assessed IHD risk and risk factors according to genetically predicted thyroid stimulating hormone (TSH), free thyroxine (FT4) and thyroid peroxidase antibody (TPOAb) positivity. Separate-sample instrumental variable analysis with genetic instruments (Mendelian randomization) was used in an extensively genotyped case (n = 64,374)-control (n = 130,681) study, CARDIoGRAMplusC4D. Associations with lipids, diabetes and adiposity were assessed using the Global Lipids Genetics Consortium Results (n = 196,475), the DIAbetes Genetics Replication And Meta-analysis case (n = 34,380)-control (n = 114,981) study, and the Genetic Investigation of ANthropometric Traits (body mass index in 152,893 men and 171,977 women, waist-hip ratio in 93,480 men and 116,741 women). Genetically predicted thyroid function was not associated with IHD (odds ratio (OR) per standard deviation for TSH 1.05, 95% confidence interval (CI) 0.97 to 1.12; for FT4 1.01, 95% CI 0.91 to 1.12; for TPOAb positivity 1.10, 95% CI 0.83 to 1.46) or after Bonferroni correction with risk factors, except for an inverse association of FT4 with low-density lipoprotein-cholesterol. The associations were generally robust to sensitivity analyses using a weighted median method and MR Egger. This novel study provides little indication that TSH, FT4 or TPOAb positivity affects IHD, despite potential effects on its risk factors.

Effects of Thyroid Autoimmunity on Early Atherosclerosis in Euthyroid Girls with Hashimoto's Thyroiditis

OBJECTIVE

In the current study, we aimed to investigate whether thyroid autoimmunity (TA) had any effect on carotid intima-media thickness (cIMT) and enhanced the risk of cardiovascular disease (CVD) independent of thyroid function (TF) in pubertal girls with Hashimoto's thyroiditis (HT).

METHODS

Sixty-six newly diagnosed euthyroid girls with HT with a mean age of 14.4±2.4 years were included in the study. The control group consisted of 41 age- and body mass index (BMI)-matched healthy girls. At enrollment, all subjects underwent physical examination including blood pressure, standing height, weight, waist circumference (WC), and hip circumference measurements. The lipid profile, high-sensitivity C-reactive protein (hs-CRP), homocysteine, blood glucose, insulin, TF, and thyroid antibodies were measured, and thyroid ultrasound and cIMT were performed.

RESULTS

There were no significant differences in anthropometric variables between the two groups, but the patients with HT had significantly higher waist-to-hip ratio (WHR). Thyroid hormones, insulin, homocysteine, and homeostatic model assessment-insulin resistance were not different between the two groups. Serum hs-CRP levels were significantly higher in patients than controls (3.4 ng/mL vs. 2.03 ng/mL), (p<0.001). Patients were also characterized by significantly higher total cholesterol (166.4±27 mg/dL vs. 151±22 mg/dL), (p<0.01) and low-density cholesterol (95.8±24.4 mg/dL vs. 82.6±20.7 mg/dL), (p<0.01) levels. Patients, regardless of TF, had significantly increased cIMT compared with controls [0.28 mm vs. 0.25 mm, (p<0.001)], and cIMT was correlated with weight-standard deviation score (SDS), BMI-SDS, WC-SDS, and WHR. This increase in cIMT was associated independently with BMI-SDS and hs-CRP levels.

CONCLUSION

TA may be related to chronic inflammation, which may cause endothelial dysfunction, a promoter of atherosclerosis in girls with HT. cIMT is a good tool for the early detection and the monitoring of early atherosclerosis in euthyroid patients with HT. Early detection of risk factors of CVD, may be helpful for planning treatment and interventions, so as to prevent complications from the disease in adulthood.

Cardiovascular comorbidity in rheumatic diseases

Patients with rheumatoid arthritis (RA) and other inflammatory joint diseases (IJDs) have an increased risk of premature death compared with the general population, mainly because of the risk of cardiovascular disease, which is similar in patients with RA and in those with diabetes mellitus. Pathogenic mechanisms and clinical expression of cardiovascular comorbidities vary greatly between different rheumatic diseases, but atherosclerosis seems to be associated with all IJDs. Traditional risk factors such as age, gender, dyslipidaemia, hypertension, smoking, obesity and diabetes mellitus, together with inflammation, are the main contributors to the increased cardiovascular risk in patients with IJDs. Although cardiovascular risk assessment should be part of routine care in such patients, no disease-specific models are currently available for this purpose. The main pillars of cardiovascular risk reduction are pharmacological and nonpharmacological management of cardiovascular risk factors, as well as tight control of disease activity.

Systemic inflammation and cardiovascular risk factors predict rapid progression of atherosclerosis in rheumatoid arthritis

OBJECTIVE

To estimate atherosclerosis progression and identify influencing factors in rheumatoid arthritis (RA).

METHODS

We used carotid ultrasound to measure intima-media thickness (IMT) in RA patients, and ascertained cardiovascular (CV) risk factors, inflammation markers and medications. A second ultrasound was performed approximately 3 years later. We calculated the progression rate by subtracting the baseline from the follow-up IMT, divided by the time between the two scans. We used logistic regression to identify baseline factors predictive of rapid progression. We tested for interactions of erythrocyte sedimentation rate (ESR) with CV risk factors and medication use.

RESULTS

Results were available for 487 RA patients. The mean (SD) common carotid IMT at baseline was 0.571 mm (0.151). After a mean of 2.8 years, the IMT increased by 0.050 mm (0.055), p≤0.001, a progression rate of 0.018 mm/year (95% CI 0.016 to 0.020). Baseline factors associated with rapid progression included the number of CV risk factors (OR 1.27 per risk factor, 95% CI 1.01 to 1.61), and the ESR (OR 1.12 per 10 mm/h, 95% CI 1.02 to 1.23). The ESR×CV risk factor and ESR×medication product terms were significant, suggesting these variables modify the association between the ESR and IMT progression.

CONCLUSIONS

Systemic inflammation and CV risk factors were associated with rapid IMT progression. CV risk factors may modify the role of systemic inflammation in determining IMT progression over time. Methotrexate and antitumour necrosis factor agents may influence IMT progression by reducing the effect of the systemic inflammation on the IMT.