Autoimmune thyroid disease and rheumatoid arthritis: where the twain meet

Autoimmune thyroid disease (AITD) is the most prevalent autoimmune disease. It shares multiple genetic, clinical, and serologic characteristics with rheumatoid arthritis (RA). Although frequently described as a classic form of single-organ autoimmunity, the AITD disease burden in a subset of patients extends well beyond the thyroid gland. This review explores the complex interaction between the two diseases and the clinical consequences when they overlap. Beyond the well-known effects of AITD on thyroid function in RA, there is mounting evidence of the association of both conditions impacting the presentation and outcomes of diabetes, metabolic syndrome, and cardiovascular disease. An increasing number of studies suggest that there are negative effects of AITD on RA disease activity both in the presence and in the absence of thyroid dysfunction. Recent evidence suggests that AITD may not only worsen the cumulative damage of RA through higher disease activity but may also worsen secondary osteoarthritis changes. Less well-known is the significant association between AITD and chronic widespread pain syndromes including fibromyalgia. Importantly, the presence of fibromyalgia, which is increased in RA patients, appears to be further increased when it overlaps with AITD. Lastly, we probe the possible influence of AITD interacting with RA on fertility and clinical depression. Key Points • Autoimmune thyroid disease is the most common autoimmune disease and is frequently associated with rheumatoid arthritis. • Autoimmune thyroid disease can present with osteoarthritis, inflammatory arthritis, and chronic widespread pain syndromes. • The co-occurrence of autoimmune thyroid disease and rheumatoid arthritis may worsen disease activity and exacerbate other disease manifestations including cardiovascular disease, fertility, and depression. • The overlap of rheumatoid arthritis with autoimmune thyroid disease needs further research and should be sought in general clinical practice.

Association of the anti-thyroid peroxidase antibody with chronic hand pain in older adults in the Third National Health and Nutrition Examination Survey: a cross-sectional study

Background

Autoimmune thyroid disease (AITD) is the commonest autoimmune disease. Although viewed as a classic form of single-organ autoimmunity, AITD is increasingly associated with non-thyroid sequelae including musculoskeletal manifestations and chronic pain syndromes. However, large population-based studies are needed.

Objectives

To examine the relationships between chronic hand pain and the AITD autoantibodies, anti-thyroid peroxidase antibody (TPOAb), and anti-thyroglobulin antibody (TgAb), in the Third National Health and Nutrition Examination Survey (NHANES III).

Design

This is a cross-sectional study.

Methods

We examined data from NHANES III on 4820 persons aged 60 years or older with respect to hand pain and its association with TPOAb and TgAb. Log-binomial regressions were fit to examine the associations between the anti-thyroid autoantibodies and hand pain.

Results

Positive TPOAb was associated with a higher prevalence of hand pain than negative TPOAb [prevalence ratio (PR) = 1.158, p = 0.048] in the unadjusted model. This association was no longer significant after controlling for age, body mass index, gender, and diabetes (p = 0.313). When positive TPOAb was considered as a categorical variable with four levels, the highest quartile was associated with hand pain in the unadjusted (PR = 1.489, p = 0.005) and adjusted models (PR = 1.325, p = 0.042). There was no significant association between TgAb and hand pain when covariates were controlled for.

Conclusion

TPOAb may be associated with the presence of chronic hand pain in persons aged over 60 years, especially at higher serum levels.

Association of anti-thyroid antibodies with radiographic knee osteoarthritis and chondrocalcinosis: a NHANES III study

Objectives:

To examine the relationships between radiographic knee osteoarthritis (RKOA), symptomatic radiographic knee osteoarthritis (sRKOA), and chondrocalcinosis, as outcome variables, and the autoimmune thyroid disease (AITD) autoantibodies, anti-thyroid peroxidase antibody (TPOAb) and anti-thyroglobulin antibody (TgAb), in the Third National Health and Nutrition Examination Survey (NHANES III) data source.

Methods:

NHANES III provided data on 2291 persons over the age of 60 years that included the osteoarthritis variables of interest RKOA, sRKOA and chondrocalcinosis, and the thyroid autoantibodies TPOAb and TgAb. A log-binomial regression model was fit to examine the relationships between anti-thyroid autoantibodies and RKOA. Modified Poisson regression models were employed for the thyroid autoantibodies compared to sRKOA and chondrocalcinosis.

Results:

Patients with higher levels of TPOAb were more likely to have chondrocalcinosis [prevalence ratio (PR) 1.247, 95% confidence interval (CI) 1.051, 1.479, p = 0.012]. A piecewise regression analysis indicated that this relationship between TPOAb and chondrocalcinosis was only observed when TPOAb was above 35 IU/ml (PR 1.482, 95% CI 1.233, 1.781, p < 0.001). Levels equal to or below 35 IU/ml were not associated with chondrocalcinosis. TPOAb was not associated with RKOA or sRKOA, and TgAb was not significantly related to any of the outcomes.

Conclusion:

There was no association of AITD autoantibodies TPOAb and TgAb with RKOA or sRKOA. However, there may be an association of TPOAb with the presence of chondrocalcinosis.

Association of spinal degenerative disc disease with thyroid autoimmunity

OBJECTIVES

Autoimmune thyroiditis (ATD) has been linked to various forms of arthritis. The relationship with spinal degenerative disc disease (DDD) is not known. We studied the association between ATD and spinal DDD.

METHODS

We performed a cross-sectional analysis of patients who had data on both anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibodies (TgAb) from January 1997 to January 2014 in Clinical Looking Glass (CLG), a data analysis software platform. Spinal DDD was confirmed by radiological diagnosis.

RESULTS

Of the 7698 patients for whom the TPOAb and TgAb values were available, 4383 patients with complete data for the following covariates; age, gender, race, ethnicity, smoking, diabetes, body mass index and thyroid stimulating hormone (TSH) levels, were included. Thirty-three percent had ATD, while 67% did not. The unadjusted odds ratio (OR) of having spinal DDD with ATD was 1.5 (95% confidence interval (CI)1.3, 1.7), p<0.001. After adjustment for covariates, ATD remained associated with a higher frequency of spinal DDD, OR 1.8 (95% CI 1.6, 2.2), p<0.001. Stratifying by BMI and TSH levels showed similar results. Additional analyses excluding patients with known connective tissue diseases and spondyloarthritis (SpA) also showed consistent results.

CONCLUSIONS

ATD is associated with increased frequency of spinal DDD independent of BMI and TSH levels, and among those without connective tissue diseases or SpA. This finding suggests that there may be an important link between thyroid autoimmunity and spinal DDD.

The transcription, translation, transport-trail and autoimmunity: Guilt by association

The autoimmune connective tissue diseases (ACTD) are a group of diseases which share clinical features and genetic inheritance. They are characterized by systemic autoimmunity and autoantibody production with a striking predilection for cellular components involved in transcription, translation and cellular transport. Although multiple triggers of autoimmunity have been proposed for this group of diseases including microbial agents such as viruses and bacteria, drugs, ultraviolet light, environmental toxins, stress, hormones and heavy metals, the prominence of autoantibodies to components of the transcription, translation, cellular transport-trail (TTTT) suggests that the agent(s) triggering the autoimmune response potentially utilize the TTTT. For the ACTD, viruses and viral agents are the likely triggers of autoimmunity as a result of aberrant viral latency with the production of autoantibodies to the components of the cellular TTTT machinery through multiple mechanisms, perhaps including molecular mimicry, bystander activation and epitope spreading.

Microangiopathic haemolytic anaemia resembling thrombotic thrombocytopenic purpura in systemic lupus erythematosus: the role of ADAMTS13

Thrombotic thrombocytopenic purpura (TTP) is a rare but frequently fatal complication of SLE. It occurs in the context of both active and inactive lupus and carries a worse overall prognosis than idiopathic acquired TTP. Recent advances in the knowledge and treatment of TTP do not seem to have brought similar improvements in the management and outcome of TTP in SLE. The illumination of the role of the von Willebrand factor multimer protease, ADAMTS13 in idiopathic TTP continues to enhance our comprehension of the pathogenesis of the disease and has contributed to improvements in diagnosis and management. We explore the overlap of TTP and SLE, and discuss the current understanding of the involvement of ADAMTS13 and its implications for patients with this uncommon form of microangiopathic haemolytic anaemia.

Annexin-1 mediates TNF-alpha-stimulated matrix metalloproteinase secretion from rheumatoid arthritis synovial fibroblasts

Annexins are intracellular molecules implicated in the down-regulation of inflammation. Recently, annexin-1 has also been identified as a secreted molecule, suggesting it may have more complex effects on inflammation than previously appreciated. We studied the role of annexin-1 in mediating MMP-1 secretion from rheumatoid arthritis (RA) synovial fibroblasts (SF) stimulated with TNF-alpha. TNF-alpha induced a biphasic secretion of annexin-1 from RA SF. Early (< or = 60 min), cycloheximide-independent secretion from preformed intracellular pools was followed by late (24 h) cycloheximide-inhibitable secretion requiring new protein synthesis. Exogenous annexin-1 N-terminal peptide Ac2-26 stimulated MMP-1 secretion in a dose- (EC(50) approximately 25 microM) and time- (8-24 h) dependent manner; full-length annexin-1 had a similar effect. Down-regulation of annexin-1 using small interfering RNA resulted in decreased secretion of both annexin-1 and MMP-1, confirming that annexin-1 mediates TNF-alpha-stimulated MMP-1 secretion. Erk, Jnk, and NF-kappaB have been implicated in MMP-1 secretion. Erk, Jnk, and NF-kappaB inhibitors had no effect on annexin-1 secretion stimulated by TNF-alpha but inhibited MMP-1 secretion in response to Ac2-26, indicating that these molecules signal downstream of annexin-1. Annexin-1 stimulation of MMP-1 secretion was inhibited by both a formyl peptide receptor antagonist and pertussis toxin, suggesting that secreted annexin-1 acts via formyl peptide family receptors, most likely FPLR-1. In contrast to its commonly appreciated anti-inflammatory roles, our data indicate that annexin-1 is secreted by RA SF in response to TNF-alpha and acts in an autacoid manner to engage FPRL-1, activate Erk, Jnk, and NF-kappaB, and stimulate MMP-1 secretion.

In vivo stabilization of mutant human transthyretin in transgenic mice

Transthyretin (TTR) is a 55 kD homotetrameric serum protein transporter of retinol binding protein charged with retinol and thyroxine (T4). The highly amyloidogenic human TTR variant in which leucine at position 55 is replaced by proline (L55P TTR) is responsible for aggressive fatal amyloidosis with peripheral and autonomic neuropathy, cardiomyopathy and nephropathy. Mice bearing one or two copies of a 19.2 kB human genomic fragment containing the entire coding sequence and the known control regions of the L55P TTR transgene, failed to develop TTR amyloidosis even though their sera contained mutant human TTR. The frequency of TTR tissue deposition was increased when the L55P TTR transgene was bred onto a murine TTR-null background. Denaturation of sera from the transgenic animals and murine TTR-knockouts expressing the human L55P TTR transgene revealed that the TTR tetramer was much more stable in the presence of the murine protein because the TTR circulates as hybrid human/murine heterotetramers. Intraperitoneal administration of diflunisal, a non-steroidal anti-inflammatory drug that binds to TTR in its T4-binding site and inhibits fibril formation in vitro, to human L55P TTR transgenic animals in which the murine TTR gene had been silenced, also stabilizes the circulating mutant protein to in vitro urea denaturation.

Amyloidogenesis is neither accelerated nor enhanced by injections of preformed fibrils in mice transgenic for wild-type human transthyretin: the question of infectivity

It is possible to accelerate amyloid formation in both the Senescence Accelerated Mouse, where ApoAIIC is the precursor, and in murine Amyloid A (AA) by the injection of preformed fibrils in the former and amyloid enhancing factor, which appears to consist of AA fibril fragments, in the latter. These two observations have raised the question of whether murine amyloids, like scrapie, are infectious. Injection of preformed fibrils into mice transgenic for many copies of the human wild-type transthyretin gene do not result in acceleration or enhancement of the process of deposition or the conversion of non-Congophilic deposits to fibrils.

Mice transgenic for human TTR have the same frequency of renal TTR deposition whether maintained in conventional or specific pathogen free environments

Mice transgenic for many copies of the human wild type transthyretin gene were bred and maintained in a specific pathogen free environment until twelve months of age. At that time, half the animals were moved to a conventional animal facility. The incidence of both transthyretin and AA amyloid was the same in both groups at two years of age, indicating that in this model, the frequency, extent or nature of TTR-amyloid deposition did not differ significantly between conventional and specific pathogen-free environments.

The genetics of the amyloidoses

The amyloidoses are diseases in which abnormalities in the secondary structure of precursor proteins result in decreased solubility under physiologic conditions, with subsequent organ compromise. A total of 18 proteins have been definitively identified as amyloid precursors associated with human disease. Mutations in the genes that encode some of these proteins produce autosomal dominant disease in mid to late adult life. Until recently, the late onset has obscured the familial nature of some of the disorders. This is especially true in the apparently sporadic disease-producing deposits found even later in life. In many instances, these deposits are derived from precursors encoded by wild-type genes (perhaps influenced by alleles that are polymorphic in the normal population); in other cases, they represent autosomal dominant disease with age-dependent penetrance. The genetic aspects of amyloid diseases produced by the deposition of four different proteins have been investigated in detail and provide insights into the particular diseases and amyloidogenesis in general.

Characterization and immunolocalization of rat liver annexin VI

Annexin VI has been purified to homogeneity from rat liver and monospecific antibodies have been produced. The antibodies have been used for immunoblot analysis of rat tissues. Annexin VI is present in most tissues, with particularly high concentrations in liver, spleen, muscle, and intestine. In liver, annexin VI constitutes approximately 0.25% of total cellular protein. Immunohistochemical studies have located annexin VI on plasma membranes of hepatocytes with enhanced concentration on bile canaliculi. Annexin VI binds in a Ca(2+)-dependent manner to a sub-cellular fraction containing membranes. In the presence of physiological concentrations of ATP, the free Ca2+ concentration required for half-maximal binding of annexin VI to membranes is significantly reduced. While annexin VI binds in vitro to membranes in the presence of Ca2+, in rat liver about 31% of the annexin VI is associated with membranes in a Ca(2+)-independent manner and its solubilization requires the presence of Triton X-100. However, studies using Triton X-114 showed no increase in the hydrophobicity of this fraction of the protein compared to the purified EGTA-soluble annexin VI.

Effects of oestrogen administration on vitamin B6 and tryptophan metabolism in the rat

1. In order to assess the effects of oestrogens on the metabolism of tryptophan and vitamin B6, ovariectomized rats have been maintained on diets providing known amounts of tryptophan, nicotinamide and vitamin B6. They received oestrone sulphate, 210 micrograms/kg body-wt per d, either incorporated in the diet for 8 weeks, or by daily intraperitoneal injection for periods of 1-3 d. 2. Oestrone sulphate administration caused a slight reduction in the concentration of pyridoxal phosphate in plasma. It had no effect on the concentration of pyridoxal phosphate in liver or kidney, the urinary excretion of 4-pyridoxic acid, the activation of erythrocyte aspartate aminotransferase (L-aspartate:2-oxo-glutarate aminotransferase, EC 2. 6. 1. 1) by incubation with added pyridoxal phosphate, or the activity of pyridoxal oxidase (aldehyde:oxygen oxido-reductase, EC 1.2.3.1) in the liver. 3. Oestrone sulphate administration caused an increase in the urinary excretion of kynurenine and a reduction in the activity of liver kynureninase (L-kynurenine hydrolase, EC 3.7.1.3). It had no effect on the urinary excretion of N1-methyl nicotinamide or the concentrations of nicotinamide nucleotides in blood, liver or kidney. 4. There was a considerable excess of the apoenzyme of kynureninase in the liver. Incubation of liver homogenates with added pyridoxal phosphate led to a 4- to 5-fold increase in activity. 5. We conclude that there is no evidence of any significant effect of oestrogens on vitamin B6. It is suggested that abnormalities of tryptophan metabolism in women receiving oestrogens, which have been widely attributed to drug-induced vitamin B6 depletion, can be accounted for by inhibition of kynureninase by oestrogen metabolites.