Antioxidant status of serum bilirubin and uric acid in patients with polymyositis and dermatomyositis

Hypouricemia as a novel predictor of mortality in anti-MDA5 positive dermatomyositis patients with ILD: A retrospective cohort study

OBJECTIVE

Anti-melanoma differentiation-associated gene 5 antibody positive dermatomyositis (MDA5+ DM) is a unique subtype of idiopathic inflammatory myopathy (IIM) that is associated with rapidly progressive interstitial lung disease (RPILD) and high mortality. This retrospective study aimed to identify predictors of mortality and discover novel easily detectable indicators.

METHODS

We retrospectively reviewed 183 MDA5+ DM-ILD patients who were from West China Hospital of Sichuan University myositis cohort, the largest single-center cohort of southwest China, from January 2016 to October 2021. Clinical characteristics were reviewed, and risk factors for mortality were determined by univariate and multivariable Cox regression analyses.

RESULTS

Of the 183 MDA5+ DM-ILD patients, 59 were presented with RP-ILD, and 53 died during the follow-up period. Compared with the survived patients, deceased patients had higher rates of dyspnea, higher concentrations of CRP, and LDH, but lower rates of heliotrope sign, lower quantity of lymphocyte and lower levels of serum uric acid (SUA). Notably, patients with hypouricemia (SUA <154 μmol/L) had higher concentrations of CRP and LDH, higher neutrophil counts, lower lymphocyte counts and higher mortality rate when compared with the non-hypouricemia group. Multivariate Cox regression analyses confirmed that hypouricemia, smoking, RPILD, high HRCT score, elevated LDH, and lymphopenia were independent risk factors for mortality in MDA5+ DM-ILD patients. Moreover, patients with hypouricemia had significantly lower survival rates than non-hypouricemia patients.

CONCLUSION

Our study identified hypouricemia as a non-redundant promising prognostic factor for the mortality of MDA5+ DM-ILD patients, which may hopefully provide insight into the prevention and pathogenesis study.

Serum uric acid is independently associated with hypertension in patients with polymyositis and dermatomyositis

Serum uric acid (UA), as an antioxidant, has been associated with hypertension in the general population. Hypertension is highly prevalent in patients with polymyositis and dermatomyositis (PM/DM). Owning elevated levels of reactive oxygen species, patients with PM/DM have lower concentrations of UA in comparison with healthy people. We explored a potential association between UA levels and hypertension in PM/DM and evaluated whether this association is independent of hypertension risk factors, PM/DM characteristics and relevant drugs. A total of 472 PM/DM patients were assessed. UA and related laboratory data were measured. Demographic, hypertension-related factors, PM/DM characteristics and drug use were assessed as potential covariates. Results were analyzed using logistic models to test the independence of the association between UA and hypertension. UA levels were higher in hypertension subjects compared to non-hypertensive PM/DM patients [284.70 (239.93-357.38) vs 264.00(222.50-322.75), p = .017]. When adjusted for hypertension risk factors, PM/DM characteristics and drugs, the odds of being a hypertensive PM/DM patient per 1 μmol/L UA increase were significantly increased: odds ratio = 1.473 (95% confidence interval:1.063-2.042, p = .020). This cross-sectional study suggests that UA levels are independently associated with hypertension in PM/DM patients.

Oxidative stress, mitochondrial dysfunction, and respiratory chain enzyme defects in inflammatory myopathies

We investigated the relationship between oxidative stress and inflammatory myopathies. We searched in the current literature the role of mitochondria and respiratory chain defects as sources of oxidative stress and reactive oxygen species production that led to muscle weakness and fatigue. Different molecules and pathways contribute to redox milieu, reactive oxygen species generation, accumulation of misfolded and carbonylated proteins that lose their ability to fulfil cellular activities. Small peptides and physical techniques proved, in mice models, to reduce oxidative stress. We focused on inclusion body myositis, as a major expression of myopathy related to oxidative stress, where mitochondrial abnormalities are causative agents as well. We described the effect of physical exercise in inclusion body myositis that showed to increase strength and to reduce beta amyloid accumulation with subsequent improvement of the mitochondrial functions. We illustrated the influence of epigenetic control on the immune system by non-coding genetic material in the interaction between oxidative stress and inflammatory myopathies.

Bilirubin as a new antioxidant in melasma

BACKGROUND

Oxidative stress and its role in the pathogenesis of cutaneous diseases have been widely investigated. However, there are few studies that have solely assessed the contribution of intracellular antioxidants in the etiopathology of melasma. Furthermore, there are convincing reports about antioxidant properties of bilirubin (Bil) and uric acid (UA) in some skin disorders but not melasma.

OBJECTIVE

This study aimed to determine serum levels of two major extracellular antioxidants (Bil and UA) levels in patients with melasma and their correlation with the severity and extent of the disease.

METHODS

In this case-control study, the serum levels of bilirubin and uric acid of 50 melasma patients were compared with 50 healthy controls. Moreover, the correlation of serum concentrations of these antioxidants with the extent and severity of the disease were assessed.

RESULTS

The serum concentration of Bil was significantly higher in the case group (p < 0.05). Furthermore, serum Bil level had a positive correlation with the extent of the melasma (correlation coefficient, +0.3; p < 0.05). No significant difference was found between the serum concentrations of UA between the study and control group. Neither Bil nor UA had a significant correlation with the severity of the disease.

CONCLUSION

Oxidative stress may play a major role in the etiopathology of melasma and bilirubin, as an antioxidant, could be involved in the process of oxidative stress.

Relationship between serum uric acid and hypertension in patients with primary Sjögren's syndrome: A retrospective cohort study

Primary Sjögren's syndrome (pSS) patients with hypertension (pSS‐HT) have a significantly increased risk of cardio‐cerebrovascular events. Serum uric acid (SUA), a potential inflammatory substance, is considered to be closely related to hypertension in the general population. Our aim is to assess the association between SUA and pSS‐HT. This is a retrospective cohort study. The diagnosis of pSS is based on the American European Consensus Classification criteria. Primary outcome was incident hypertension in pSS patients. Cox regression model was used to estimate the hazard ratios (HR) and 95% CI of SUA in pSS‐HT. The authors also plotted Kaplan–Meier plots to assess the cumulative risk of first hypertension in patients with hyperuricemia and normal uric acid. In addition, the dose‐response curve was also used to discuss the relationship between SUA and pSS‐HT. Finally, three hundred and fifty‐one pSS patients were enrolled from May 2011 to May 2020, of which 166 cases developed hypertension within a mean follow‐up of 3.91 years. Univariate Cox regression demonstrated that SUA was associated with the onset of hypertension in pSS (HR: 1.005 95%Cl: 1.002–1.009). After adjusting for the potential risk factors, the relationship remained unchanged (HR: 1.003, 95%Cl: 1.001–1.005). Kaplan‐Meier survival analysis showed a statistically significant difference of hypertension risk between hyperuricemia patients and normal uric acid patients (P = .026). There was also a significant dose‐effect relationship between SUA and hypertension in pSS in dose‐response model. In this study, the authors find that SUA may be closely associated with the development of hypertension in pSS, which is also confirmed by our dose‐response model. Therefore, SUA could be considered in the management of pSS‐HT.

Serum Uric Acid and High-Sensitivity C-Reactive Protein as Predictors of Cognitive Impairment in Patients with Cerebral Infarction

BACKGROUND

Cognitive impairment induced by cerebral infarction has become a devastating health problem. More efficient predictors are required to evaluate the potential cognitive decline after cerebral infarction in clinic. Serum uric acid (UA) and high-sensitivity C-reactive protein (hs-CRP) are two factors reported to correlate with cognitive impairment. However, the understanding on serum UA and hs-CRP with cognitive dysfunction remains unclear.

METHODS

Serum UA and hs-CRP were evaluated in patients with cerebral infarction (n = 197) using single factor analysis and multivariate logistic regression analysis. Clinical and pathological characteristics were analyzed by logistic regression, respectively, and the results demonstrated the correlation between the pathological characteristics and the cognitive impairment post cerebral infarction. Montreal Cognitive Assessment (MoCA) was used to evaluate the patients' cognitive function, and patients with a MoCA score <26 were recognized as with cognitive impairment.

RESULTS

Clinical characteristics related to cognitive impairment, including age, gender, blood pressure, serum UA, and hs-CRP were collected and analyzed. Serum UA and hs-CRP were identified to be potential predictors for post-stroke cognitive dysfunction, with higher serum UA levels correlated with better cognitive function and higher hs-CRP levels correlated with worse cognitive impairment.

CONCLUSION

Serum UA and hs-CRP are two predictors for cognitive impairment post cerebral infarction.

Clinical and pathological findings of chronic actinic dermatitis

BACKGROUND

Chronic actinic dermatitis (CAD) is a recurrent photosensitive disease occurs predominantly in elderly men on sun-exposed areas, which seriously affect the patient's life quality. The etiology of CAD remains unknown.

METHODS

Sixty-six CAD patients, 66 atopic dermatitis (AD) patients, and 46 healthy people were enrolled into this study. Patient-level data were obtained from the electronic medical record and laboratory databases. We also obtained 29 tissue samples including 16 lichenoid lesions, 7 minimal erythematous dose (MED) analysis induced lesions, and 6 normal skin samples. Histopathologic and immunohistochemical analysis were performed.

RESULTS

In the clinical characteristics, albumin was lower and uric acid was higher significantly in patients diagnosed as CAD. The infection rate of CAD patient after skin biopsy was considerably high (23.3%). The serum allergen test was prone to be negative in CAD patients. Lymphocytes were the dominate infiltrating cells in early and late CAD lesions, while more CD4+, CD8+, CD69+, and CD103 + cells were found in the late lesions. There is no difference in CD4+/CD8 + ratio and CD69+/CD103 + ratio among groups. More mast cells were observed in the early-stage lesions, and more dendritic cell was observed in the late-stage lesions.

CONCLUSIONS

CAD patients have certain oxidative stress and are prone to be infected after skin biopsy. Serum allergen detection is of little significance for CAD diagnosis. Mast cells may be involved in the early process of CAD, while dendritic cells and tissue-resident memory T cell (TRM) may be related to the chronic process of the disease.

Evaluation of serum uric acid levels in patients with rosacea

Rosacea is an inflammatory skin disease with a chronic course. Although the pathogenesis of rosacea is not completely understood, it is regarded as an inflammatory process. The aim of the present study was to evaluate uric acid (UA) levels in patients with rosacea and to detect the correlation of UA levels with disease activity. A total of 61 patients with rosacea and 64 sex- and age-matched controls were included in the study. Demographic characteristics, medical history, and dermatological examination of the patient and control groups were recorded. Concentrations of serum UA and C-reactive protein (CRP) were evaluated and compared in both groups. This study included 61 patients with rosacea (39 females, 22 males, median age = 30 years) and 64 age- and sex-matched controls. Metabolic syndrome was significantly more common in patients with rosacea than in the control group. Patients with rosacea had significantly higher body mass index (BMI) values compared with those of controls. Serum UA and CRP values were significantly higher in the rosacea group than values in the control group. There was no statistically significant correlation between serum UA level and clinical rosacea severity. This study suggests that rosacea is not only a skin-related disease but also an inflammatory disease that can be related to higher uric acid levels, BMI values, and metabolic syndrome. It may be recommended that clinicians pay careful attention to the clinical follow-up of these patients to avoid missed associated comorbidities.