Morphometric evaluation of nitric oxide synthase isoforms and their cytokine regulators predict pulmonary dysfunction and survival in systemic sclerosis

Abstract

Because histopathological changes in the lungs of patients with systemic sclerosis (SSc) are consistent with alveolar and vessel cell damage, we presume that this interaction can be characterized by analyzing the expression of proteins regulating nitric oxide (NO) and plasminogen activator inhibitor-1 (PAI-1) synthesis. To validate the importance of alveolar-vascular interactions and to explore the quantitative relationship between these factors and other clinical data, we studied these markers in 23 cases of SSc nonspecific interstitial pneumonia (SSc-NSIP). We used immunohistochemistry and morphometry to evaluate the amount of cells in alveolar septa and vessels staining for NO synthase (NOS) and PAI-1, and the outcomes of our study were cellular and fibrotic NSIP, pulmonary function tests, and survival time until death. General linear model analysis demonstrated that staining for septal inducible NOS (iNOS) related significantly to staining of septal cells for interleukin (IL)-4 and to septal IL-13. In univariate analysis, higher levels of septal and vascular cells staining for iNOS were associated with a smaller percentage of septal and vascular cells expressing fibroblast growth factor and myofibroblast proliferation, respectively. Multivariate Cox model analysis demonstrated that, after controlling for SSc-NSIP histological patterns, just three variables were significantly associated with survival time: septal iNOS (P=0.04), septal IL-13 (P=0.03), and septal basic fibroblast growth factor (bFGF; P=0.02). Augmented NOS, IL-13, and bFGF in SSc-NSIP histological patterns suggest a possible functional role for iNOS in SSc. In addition, the extent of iNOS, PAI-1, and IL-4 staining in alveolar septa and vessels provides a possible independent diagnostic measure for the degree of pulmonary dysfunction and fibrosis with an impact on the survival of patients with SSc.

Evaluation of multiple-flows exhaled nitric oxide in idiopathic and non-idiopathic interstitial lung disease

“…Among eNO parameters, FeNO 350 and CANO, detected according to recent ERS statement, resulted the most promising biomarkers with the highest statistical differences. CTD-ILD patients showed the highest values of peripheral lung NO and CANO than other ILDs; this finding could be explained by a more pronounced inflammatory process occurring in these rheumatic diseases stimulating an aberrant overexpression of inducible NO synthetase in lung tissue, as reported [23]. Moreover, DLCO percentages were not significantly different among ILD subgroups, suggesting that increased CANO levels in CTD-ILD patients were not related to a worse diffusion lung capacity.…”

Cardiovascular-renal complications and the possible role of plasminogen activator inhibitor: a review

“…PAI-1 expression promoted by TGF-β and the renin–angiotensin–aldosterone system has been noted in clinical conditions including nephrosclerosis of aging [ 74 ], diabetic nephropathy [ 75 ], focal sclerosis [ 76 ], scleroderma [ 77 ], radiation injury [ 78 ], cyclosporine toxicity [ 79 ] and transplant allograft nephropathy [ 80 ]. The same phenomenon has been observed in experimental models: 5/6 nephrectomy [ 20 ], protein overload [ 81 ], salt and angiotensin exposure [ 82 ], bleomycin-induced pulmonary sclerosis [ 83 ], nitric oxide synthase inhibitor [ 84 ], TGF-β overexpression [ 85 ] and unilateral ureteral obstruction [ 86 ].…”

CB1R and iNOS are distinct players promoting pulmonary fibrosis in Hermansky–Pudlak syndrome

“…17 In addition, iNOS protein levels in human lung tissue are strongly correlated with the severity of PF, whereas low expression of iNOS is associated with reduced risk of death in PF. 50 Consequently, iNOS inhibitors showed antifibrotic efficacy in rodent models of experimental fibrosis. 51 Here, we discovered a previously unrecognized role of iNOS in regulating IL-11 expression and secretion by activated lung fibroblasts (Figure 7).…”

“…For instance, an early proliferative response of human pulmonary fibroblasts to inflammatory stimuli is associated with increased iNOS gene expression 17 . In addition, iNOS protein levels in human lung tissue are strongly correlated with the severity of PF, whereas low expression of iNOS is associated with reduced risk of death in PF 50 . Consequently, iNOS inhibitors showed antifibrotic efficacy in rodent models of experimental fibrosis 51 .…”