Anti-insulin antibodies and the natural autoimmune response in systemic lupus erythematosus

A network causal relationship between type-1 diabetes mellitus, 25-hydroxyvitamin D level and systemic lupus erythematosus: Mendelian randomization study

BACKGROUND

Observational studies have suggested a relationship between type-1 diabetes mellitus (T1DM) and systemic lupus erythematosus (SLE). In both autoimmunities, 25-hydroxyvitamin D (25-OHD) deficiency is common. However, the causality between T1DM, 25-OHD level and SLE remains largely unknown.

METHODS

Independent genetic variants associated with T1DM, 25-OHD level, and SLE from the largest genome-wide association studies were used to conduct two-sample bidirectional Mendelian randomization (BIMR) and two-step Mendelian randomization (MR) analysis to estimate causal relationship between T1DM, 25-OHD level and SLE, and further multivariable Mendelian randomization (MVMR) was used to verify direct causality of T1DM and 25-OHD level on SLE. A series of sensitivity analysis as validation of primary MR results were performed.

RESULTS

Consistent with the results of BIMR, there was strong evidence for a direct causal effect of T1DM on the risk of SLE (ORMVMR-IVW = 1.249, 95% CI = 1.148-1.360, PMVMR-IVW = 1.25×10-5), and 25-OHD level was negatively associated with the risk of SLE (ORMVMR-IVW = 0.305, 95% CI = 0.109-0.857, PMVMR-IVW = 0.031). We also observed a negative causal effect of T1DM on 25-OHD level (ORBIMR-IVW = 0.995, 95% CI = 0.991-0.999, PBIMR-IVW = 0.030) while the causal effect of 25-OHD level on the risk of T1DM did not exist (PBIMR-IVW = 0.106). In BIMR analysis, there was no evidence for causal effects of SLE on the risk of T1DM and 25-OHD level (PBIMR-IVW > 0.05, respectively).

CONCLUSION

Our MR analysis suggested that there was a network causal relationship between T1DM, 25-OHD level and SLE. T1DM and 25-OHD level both have causal associations with the risk of SLE, and 25-OHD level could be a mediator in the causality of T1DM and SLE.

Interplay of diabetes mellitus and rheumatic diseases amidst the COVID-19 pandemic: influence on the risk of infection, outcomes, and immune responses

Outcomes of COrona VIrus Disease-19 (COVID-19) in patients with rheumatic diseases (RDs) reported in various studies are heterogenous owing to the influence of age and comorbidities which have a significant bearing on the infection risk, severity, morbidity, and mortality. Diabetes mellitus (DM) and RDs are closely linked with underlying pathobiology and treatment of RDs affecting the risk for DM as well as the glycemic control. Hence, we undertook this narrative review to study the influence of DM on outcomes of COVID-19 in patients with RDs. Additionally, aspects of patient attitudes and immune response to COVID-19 vaccination were also studied. The databases of MEDLINE/PubMed, Scopus, and Directory of Open Access Journals (DOAJ) were searched for relevant articles. Studies from mixed cohorts revealed insufficient data to comment on the influence of DM on the risk of infection, while most studies showed twice the odds for hospitalization and mortality with DM. Specific cohorts of rheumatoid arthritis and systemic lupus erythematosus revealed a similar association. Poor health was noted in patients with spondyloarthritis and DM during the pandemic. The presence of DM did not affect patient attitudes towards vaccination and did not predispose to additional vaccine-related adverse effects. Immune response to inactivated vaccines was reduced but mRNA vaccines were maintained in patients with DM. Detailed assessment of DM with its duration, end-organ damage, and glycemic control along with a focused association of DM with various aspects of COVID-19 like risk, hospitalization, severity, mortality, post-COVID sequelae, immune response to infection, and vaccination are needed in the future. Key Points • Diabetes mellitus is associated with the severity of infection, COVID-19-related hospitalization, and mortality in rheumatic diseases across most studies but studies analyzing its specific role are lacking. • Poor outcomes of COVID-19 in RA and poor health in spondyloarthritis are strongly associated with diabetes mellitus. • Diabetes mellitus may negatively influence the humoral response to inactivated vaccines but does not seem to affect the immune responses to mRNA vaccines. • Diabetes mellitus does not influence the attitude towards vaccination or deviation from the prescribed medications during the pandemic.

Nephrotic syndrome in the course of type 1 diabetes mellitus and systemic lupus erythematosus with secondary antiphospholipid syndrome - diagnostic and therapeutic problems

Nephrotic syndrome (NS) can be a symptom of many autoimmune, metabolic, or infectious diseases. Kidney involvement is often observed in the course of diabetes mellitus (DM) and systemic lupus erythematosus (SLE). The development of NS with coexisting SLE and DM generates serious diagnostic problems. In this paper, the authors present diagnostic and therapeutic dilemmas in a patient with long-lasting DM, SLE, and secondary antiphospholipid syndrome, in whom NS symptoms appeared. Histopathological examination of the kidney confirmed the diagnosis of lupus nephritis. Immunosuppressive and anticoagulant drugs were used.

The authors demonstrated that the character of morphologic lesions in the kidney biopsy can help in diagnosis, nephropathy classification, and further therapeutic decisions, which are distinct in both diseases.

Impact of Diabetes Mellitus on the Risk of End-Stage Renal Disease in Patients with Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) patients are associated with insulin resistance and are at higher risk to develop diabetes mellitus (DM). SLE and DM could lead to renal failure respectively. However, it is unknown whether DM increases the risk of end-stage renal disease (ESRD) in SLE patients. This study aimed to evaluate potential synergistic effect of DM on SLE patients for development of ESRD. We conducted this study by using National Health Insurance Research Database of Taiwan. We recruited SLE patients with newly-diagnosed DM as the study cohort. A comparison cohort at a 1:1 ratio of SLE patients without DM matched by age, sex, age at the diagnosis of SLE, duration between diagnosis of SLE and DM, and various comorbidities through propensity score matching were recruited. After 5.01 ± 3.13 years follow-up, the incidence of ESRD was significantly higher in the DM group than in the non-DM group (Incidence rate ratio: 2.71; 95% CI: 1.70-4.32). After control of confounding factors, DM was not an independent risk factor of ESRD. After starting dialysis, DM patients had a similar mortality rate to those without DM. In summary, SLE patients superimposed with subsequent DM are associated with potentially higher risk to develop ESRD.

Update on cardiovascular disease in lupus

PURPOSE OF REVIEW

Atherosclerotic cardiovascular disease confers significant morbidity and mortality in patients with systemic lupus erythematosus (SLE) and cannot be fully explained by traditional cardiovascular risk factors. Recent immunologic discoveries have outlined putative pathways in SLE that may also accelerate the development of atherosclerosis.

RECENT FINDINGS

Aberrant innate and adaptive immune responses implicated in lupus pathogenesis may also contribute to the development of accelerated atherosclerosis in these patients. Defective apoptosis, abnormal lipoprotein function, autoantibodies, aberrant neutrophil responses, and a dysregulated type I interferon pathway likely contribute to endothelial dysfunction. SLE macrophages have an inflammatory phenotype that may drive progression of plaque.

SUMMARY

Recent discoveries have placed increased emphasis on the immunology of atherosclerotic cardiovascular disease. Understanding the factors that drive the increased risk for cardiovascular disease in SLE patients may provide selective therapeutic targets for reducing inflammation and improving outcomes in atherosclerosis.

Elevation of plasma interleukin-18 concentration is associated with insulin levels in patients with systemic lupus erythematosus

We previously reported that systemic lupus erythematosus (SLE) patients have a higher risk of insulin resistance and abnormal insulin secretion. Recent studies demonstrated that interleukin (IL)-18, a novel pro-inflammatory cytokine, may be involved in triggering the inflammatory processes in SLE and the concentrations of circulating IL-18 in SLE patients were significantly higher than those in healthy subjects. IL-12 has a synergistic effect with IL-18, and both cytokines are inducers of interferon γ. The objective of this study was to identify the effect of fasting insulin levels on circulating concentrations of IL-18, IL-12 and IFN-γ in patients with SLE. Plasma levels of proinflammatory Th-1 cytokines were determined by enzyme-linked immunosorbent assay in a total of 70 female SLE patients and 34 age-matched healthy females. Insulin resistance (IR) and secretion were evaluated by homeostasis model assessment (HOMA). All patients were further classified into subgroups based on the quartiles of fasting insulin levels. SLE patients with fasting insulin levels in the top quartile compared with other quartiles had significantly higher plasma levels of IL-18. The presence of insulin auto-antibodies (IAA) in SLE patients had no influence on plasma levels of IL-18. In addition, fasting insulin levels and HOMA IR were positively correlated with IL-18 in all SLE patients, respectively. In conclusion, elevated circulating IL-18 concentrations corresponded with increases in fasting insulin levels and the status of insulin resistance in patients with SLE.

Elevation of fasting insulin and its association with cardiovascular disease risk in women with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is associated with premature atherosclerosis. We previously showed that SLE patients have a higher risk of insulin resistance (IR) and abnormal insulin secretion. The present study was to further investigate the relationship between fasting insulin levels and both classic and novel cardiovascular risk factors in patients with SLE. Body mass index (BMI), fasting glucose and insulin, lipid profile, oxidation markers, fibrinolytic factors, vascular function factors, and disease-specific variables were determined in a total of 87 female SLE patients. The homeostasis model assessment (HOMA) was used to evaluate the IR and secretion. SLE patients had significantly higher fasting insulin, HOMA IR, HOMA beta-cell, titers of autoantibodies against oxidized low density lipoprotein, systolic blood pressure, homocysteine, and brachial-ankle pulse wave velocity (baPWV) than age-matched healthy controls. There were no statistical differences in disease duration, anti-dsDNA, C3, C4, disease activity, and medication dosage between SLE patients stratified by fasting insulin levels. However, mean values for BMI, insulin, HOMA IR, HOMA beta-cell, triglyceride (TG), homocysteine, and baPWV were significantly higher in the SLE patients with hyperinsulinemia when compared with those SLE controls. In addition, fasting insulin levels were positively correlated with TG, homocysteine, blood pressure, plasminogen activator inhibitor 1, and baPWV in SLE patients. The elevation of fasting insulin levels in SLE patients is not only associated with IR, but is related to classic and novel cardiovascular risk factors. This study concludes that there is an insulin-related cardiovascular disease risk in SLE.

High insulin levels and increased low-density lipoprotein oxidizability in pediatric patients with systemic lupus erythematosus

OBJECTIVE

To examine low-density lipoprotein (LDL) size, LDL susceptibility to oxidation, and plasma insulin levels in children with systemic lupus erythematosus (SLE).

METHODS

Fifty-nine SLE patients and 59 healthy, age-matched control subjects were studied. LDL size was determined by gradient gel electrophoresis. LDL oxidizability was assessed by lag time for conjugated diene formation during copper incubation. Plasma levels of fasting insulin, glucose, lipids, lipoproteins, apolipoproteins B and A-I, and fatty acids were also measured.

RESULTS

Compared with control subjects, SLE patients showed significantly higher plasma insulin levels and increased susceptibility of LDLs to oxidation. Patients with active disease were more likely than patients with inactive disease or control subjects to have the following lipid characteristics: small, dense LDL subclass, elevated total cholesterol levels, elevated LDL cholesterol levels, elevated triglyceride levels, and low levels of high-density lipoprotein cholesterol (HDL-C). Statistically significant direct correlations were observed between disease activity and triglyceride levels and between disease activity and lag time, whereas significant inverse correlations were found between disease activity and HDL-C levels and between disease activity and LDL size. Prednisone dosage explained only 15.6% of the variance in insulin levels.

CONCLUSION

SLE patients have higher plasma insulin levels and increased LDL oxidizability compared with healthy control subjects. These abnormalities may contribute to the accelerated atherosclerosis observed in patients with SLE.