Exhaled nitric oxide, pulmonary function, and disease activity in children with systemic lupus erythematosus

Fractional exhaled nitric oxide in idiopathic pulmonary arterial hypertension and mixed connective tissue disease complicating pulmonary hypertension

BACKGROUND

Fractional exhaled nitric oxide (FeNO) has been extensively studied in various causes of pulmonary hypertension (PH), but its utility as a noninvasive marker remains highly debated. The objective of our study was to assess FeNO levels in patients with idiopathic pulmonary arterial hypertension (IPAH) and mixed connective tissue disease complicating pulmonary hypertension (MCTD-PH), and to correlate them with respiratory functional data, disease severity, and cardiopulmonary function.

METHODS

We collected data from 54 patients diagnosed with IPAH and 78 patients diagnosed with MCTD-PH at the Shanghai Pulmonary Hospital Affiliated to Tongji University. Our data collection included measurements of brain natriuretic peptide (pro-BNP), cardiopulmonary exercise test (CPET), pulmonary function test (PFT), impulse oscillometry (IOS), and FeNO levels. Additionally, we assessed World Health Organization functional class (WHO-FC) of each patient.

RESULTS

(1) The fractional exhaled concentration of nitric oxide was notably higher in patients with IPAH compared to those with MCTD-PH. Furthermore, within the IPAH group, FeNO levels were found to be lower in cases of severe IPAH compared to mild IPAH (P = 0.024); (2) In severe pulmonary hypertension as per the WHO-FC classification, FeNO levels in IPAH exhibited negative correlations with FEV1/FVC (Forced Expiratory Velocity at one second /Forced Vital Capacity), MEF50% (Maximum Expiratory Flow at 50%), MEF25%, and MMEF75/25% (Maximum Mid-expiratory Flow between 75% and 25%), while in severe MCTD-PH, FeNO levels were negatively correlated with R20% (Resistance at 20 Hz); (3) ROC (Receiving operator characteristic curve) analysis indicated that the optimal cutoff value of FeNO for diagnosing severe IPAH was 23ppb; (4) While FeNO levels tend to be negatively correlated with peakPETO2(peak end-tidal partial pressure for oxygen) in severe IPAH, in mild IPAH they had a positive correlation to peakO2/Heart rate (HR). An interesting find was observed in cases of severe MCTD-PH, where FeNO levels were negatively correlated with HR and respiratory exchange ratio (RER), while positively correlated with O2/HR throughout the cardiopulmonary exercise test.

CONCLUSION

FeNO levels serve as a non-invasive measure of IPAH severity. Although FeNO levels may not assess the severity of MCTD-PH, their significant makes them a valuable tool when assessing severe MCTD-PH.

The relationship of polluted air and drinking water sources with the prevalence of systemic lupus erythematosus: a provincial population-based study

Environmental exposures interact with genetic factors has been thought to influence susceptibility of systemic lupus erythematosus (SLE) development. To evaluate the effects of environmental exposures on SLE, we conducted a population-based cohort study across Jiangsu Province, China, to examine the associations between the living environment including air and water pollution, population density, economic income level, etc. and the prevalence and mortality of hospitalized SLE (h-SLE) patients. A total of 2231 h-SLE patients were retrieved from a longitudinal SLE database collected by the Jiangsu Lupus Collaborative Group from 1999 to 2009. The results showed that: It existed regional differences on the prevalence of h-SLE patients in 96 administrative districts; The distribution of NO₂ air concentration monitored by atmospheric remote sensors showed that three of the ultra-high-prevalence districts were located in the concentrated chemical industry emission area; h-SLE patient prevalence was positively correlated with the excessive levels of nitrogen in drinking water; The positive ratio of pericarditis and proteinuria was positively correlated with the prevalence of h-SLE patients and pollution not only induced a high h-SLE patient prevalence but also a higher mortality rate, which might be attributed to NOx pollution in the air and drinking water. In summary, our data suggested that NOx in air and drinking water may be one of the important predispositions of SLE, especially for patients with renal involvement.

Malar rash is a predictor of subclinical airway inflammation in patients with systemic lupus erythematosus: a pilot study

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic, auto-immune, multi-organ disease that can affect both the skin and the lungs. Malar rash is a common skin manifestation of SLE and is linked to SLE disease activity, whereas lung involvement is a generally negative prognostic factor for these patients. However, a sensitive and non-invasive screening tool for potential lung involvement in SLE patients is still not available.

METHODS

This study aimed to investigate the relationship between malar rash and airway inflammation in adult SLE patients who were not known to have any lung involvement (clinical or radiologic). The study comprised of the measurement of the concentration of NO in exhaled breath or fraction of exhaled nitric oxide (FeNO) and levels were compared between those with and without malar rash. This tool is considered as a sensitive and non-invasive method that is routinely used in patients with asthma or other respiratory diseases to identify airway inflammation.

RESULTS

A total of 125 patients (100 females, 25 males) were enrolled during the study period from January 2011 to December 2014. Patients with malar rash (N = 35) had a significant decrease in serum levels of C4 (p < 0.05) compared to patients without malar rash (N = 90). The mean levels of FeNO in overall patients were 36.44 ± 8.87 ppb. A statistically significant difference in FeNO₅₀ values between patients with malar rash (43.46 ± 6.72 ppb) and without (29.43 ± 3.64 ppb) was found (p < 0.001). FeNO₅₀ values were inversely correlated only with serum C4 (p < 0.01). However, no correlation between FeNO₅₀ values and SLE clinical disease activity scores was found.

CONCLUSIONS

The presence of a malar rash may predict sub-clinical airway inflammation in SLE patients. Further prospective studies are needed to confirm the usefulness of FeNO measurements in monitoring SLE-associated airway inflammation.