[Lung-protective effect of esketamine combined with distal limb ischemic preconditioning in elderly patients undergoing thoracoscopic radical surgery for lung cancer: a randomized controlled trial in 160 cases].

OBJECTIVE: To evaluate the effect of esketamine combined with distal limb ischemic preconditioning (LIP) for lung protection in elderly patients undergoing thoracoscopic radical surgery for lung cancer. METHODS: This randomized trial was conducted in 160 patients undergoing elective thoracoscopic surgery for lung cancer, who were randomized into control group (with saline injection and sham LIP), esketamine group, LIP group, and esketamine + LIP group (n=40). Before anesthesia induction, according to the grouping, the patients received an intravenous injection with 0.5 mg/kg esketamine or 10 ml saline (in control group). LIP was induced by applying a tourniquet 1-2 cm above the popliteal fossa in the left lower limb to block the blood flow for 5 min for 3 times at the interval of 5 min, and sham LIP was performed by applying the tourniquet without pressurization for 30 min. Oxygenation index (OI) and alveolar-arterial PO2 difference (A-aDO2) were calculated before induction (T0), at 30 min (T0.5) and 1 h (T1) of one-lung ventilation (OLV), and at 1 h after two-lung ventilation (T3). Serum levels of SP-D, CC-16 and TNF-α were measured by ELISA at T0, T1, T2 (2 h of OLV), T3, and 24 h after the operation (T4). The length of hospital stay and postoperative pulmonary complications of the patients were recorded. RESULTS: Compared with those in the control group, the patients in the other 3 groups had significantly lower CC-16, SP-D and TNF-α levels, shorter hospital stay, and lower incidences of lung infection and lung atelectasis (all P < 0.05). Serum CC-16, SP-D and TNF-α levels, hospital stay, incidences of complications were significantly lower or shorter in the combined treatment group than in esketamine group and LIP group (all P < 0.05). CONCLUSION: In elderly patients undergoing thoracoscopic radical surgery for lung cancer, treatment with esketamine combined with LIP can alleviate acute lung injury by enhancing anti-inflammatory response to shorten postoperative hospital stay, reduce lung complications and promote the patients' recovery.

Serum VEGF-A levels on admission in COVID-19 patients correlate with SP-D and neutrophils, reflecting disease severity: A prospective study.

BACKGROUND AND OBJECTIVE: The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in significant global morbidity and mortality. This study aimed to investigate the clinical significance of serum vascular endothelial growth factor A (VEGF-A) in COVID-19 patients and its association with disease severity and pulmonary injury. METHODS: We prospectively collected data from 71 hospitalized COVID-19 patients between June 2020 and January 2021. Patients were classified as either mild or severe based on their oxygen requirements during hospitalization. Serum VEGF-A levels were measured using an ELISA kit. RESULTS: In comparison to mild cases, significantly elevated serum VEGF-A levels were observed in severe COVID-19 patients. Furthermore, VEGF-A levels exhibited a positive correlation with white blood cell count, neutrophil count, and lymphocyte count. Notably, serum surfactant protein-D (SP-D), an indicator of alveolar epithelial cell damage, was significantly higher in patients with elevated VEGF-A levels. CONCLUSION: These results suggest that elevated serum VEGF-A levels could serve as a prognostic biomarker for COVID-19 as it is indicative of alveolar epithelial cell injury caused by SARS-CoV-2 infection. Additionally, we observed a correlation between VEGF-A and neutrophil activation, which plays a role in the immune response during endothelial cell injury, indicating a potential involvement of angiogenesis in disease progression. Further research is needed to elucidate the underlying mechanisms of VEGF-A elevation in COVID-19.

The effects of robot-assisted laparoscopic surgery with Trendelenburg position on short-term postoperative respiratory diaphragmatic function.

OBJECTIVE: To study how Pneumoperitoneum under Trendelenburg position for robot-assisted laparoscopic surgery impact the perioperative respiratory parameters, diagrammatic function, etc. METHODS: Patients undergoing robot-assisted laparoscopic surgery in the Trendelenburg position and patients undergoing general surgery in the supine position were selected. The subjects were divided into two groups according to the type of surgery: robot-assisted surgery group and general surgery group. ① Respiratory parameters such as lung compliance, oxygenation index, and airway pressure were recorded at 5 min after intubation, 1 and 2 h after pneumoperitoneum. ② Diaphragm excursion (DE) and diaphragm thickening fraction (DTF) were recorded before entering the operating room (T1), immediately after extubation (T2), 10 min after extubation (T3), and upon leaving the postanesthesia care unit (T4). ③ Peripheral venous blood (5 ml) was collected before surgery and 30 min after extubation and was analyzed by enzyme-linked immunosorbent assay to determine the serum concentration of Clara cell secretory protein 16 (CC16) and surfactant protein D (SP-D). RESULT: ① Compared with the general surgery group (N = 42), the robot-assisted surgery group (N = 46) presented a significantly higher airway pressure and lower lung compliance during the surgery(P < 0.001). ② In the robot-assisted surgery group, the DE significantly decreased after surgery (P < 0.001), which persisted until patients were discharged from the PACU (P < 0.001), whereas the DTF only showed a transient decrease postoperatively (P < 0.001) and returned to its preoperative levels at discharge (P = 0.115). In the general surgery group, the DE showed a transient decrease after surgery(P = 0.011) which recovered to the preoperative levels at discharge (P = 1). No significant difference in the DTF was observed among T1, T2, T3, and T4. ③ Both the general and robot-assisted surgery reduced the postoperative serum levels of SP-D (P < 0.05), while the robot-assisted surgery increased the postoperative levels of CC16 (P < 0.001). CONCLUSION: Robot-assisted laparoscopic surgery significantly impairs postoperative diaphragm function, which does not recover to preoperative levels at PACU discharge. Elevated levels of serum CC16 after surgery suggest potential lung injury. The adverse effects may be attributed to the prolonged Trendelenburg position and pneumoperitoneum during laparoscopic surgery.

Idiopathic pulmonary fibrosis-specific Bayesian network integrating extracellular vesicle proteome and clinical information.

Idiopathic pulmonary fibrosis (IPF) is a progressive disease characterized by severe lung fibrosis and a poor prognosis. Although the biomolecules related to IPF have been extensively studied, molecular mechanisms of the pathogenesis and their association with serum biomarkers and clinical findings have not been fully elucidated. We constructed a Bayesian network using multimodal data consisting of a proteome dataset from serum extracellular vesicles, laboratory examinations, and clinical findings from 206 patients with IPF and 36 controls. Differential protein expression analysis was also performed by edgeR and incorporated into the constructed network. We have successfully visualized the relationship between biomolecules and clinical findings with this approach. The IPF-specific network included modules associated with TGF-ß signaling (TGFB1 and LRC32), fibrosis-related (A2MG and PZP), myofibroblast and inflammation (LRP1 and ITIH4), complement-related (SAA1 and SAA2), as well as serum markers, and clinical symptoms (KL-6, SP-D and fine crackles). Notably, it identified SAA2 associated with lymphocyte counts and PSPB connected with the serum markers KL-6 and SP-D, along with fine crackles as clinical manifestations. These results contribute to the elucidation of the pathogenesis of IPF and potential therapeutic targets.

Surfactant protein D prevents mucin overproduction in airway goblet cells via SIRPα.

Mucin overproduction is a common feature of chronic airway diseases such as asthma and chronic obstructive pulmonary disease (COPD), and exacerbates their underlying respiratory condition. Surfactant protein D (SP-D) protects against airway diseases through modulation of immune reactions, but whether it also exerts direct effects on airway epithelial cells has remained unclear. Therefore, we sought to investigate the inhibitory role of SP-D on mucin production in airway epithelial cells. We prepared air-liquid interface (ALI) cultures of human primary bronchial epithelial cells (HBECs), which recapitulated a well-differentiated human airway epithelium. Benzo(a)pyrene (BaP), a key toxicant in cigarette smoke, induced mucin 5AC (MUC5AC) production in ALI-cultured HBECs, airway secretory cell lines, and airway epithelia of mice. Then, the protective effects of SP-D against the BaP-induced mucin overproduction were examined. BaP increased MUC5AC production in ALI cultures of HBECs, and this effect was attenuated by SP-D. SP-D also suppressed the BaP-induced phosphorylation of extracellular signal-regulated kinase (ERK) and MUC5AC expression in NCI-H292 goblet-like cells, but not in NCI-H441 club-like cells. Signal regulatory protein α (SIRPα) was found to be expressed in HBECs and NCI-H292 cells but absent in NCI-H441 cells. In NCI-H292 cells, SP-D activated SH2 domain-containing tyrosine phosphatase-1 (SHP-1), downstream of SIRPα, and knockdown of SIRPα abolished the suppressive effects of SP-D on BaP-induced ERK phosphorylation and MUC5AC production. Consistent with these in vitro findings, intratracheal instillation of SP-D prevented the BaP-induced phosphorylation of ERK and Muc5ac expression in airway epithelial cells in a mouse model. SP-D acts directly on airway epithelial cells to inhibit mucin secretion through ligation of SIRPα and SHP-1-mediated dephosphorylation of ERK. Targeting of SIRPα is therefore a potential new therapeutic approach to suppression of mucin hypersecretion in chronic airway diseases such as COPD and asthma.

Sodium butyrate ameliorates sepsis-associated lung injury by enhancing gut and lung barrier function in combination with modulation of CD4+Foxp3+ regulatory T cells.

Sepsis-associated lung injury often coexists with intestinal dysfunction. Butyrate, an essential gut microbiota metabolite, participates in gut-lung crosstalk and has immunoregulatory effects. This study aims to investigate the effect and mechanism of sodium butyrate (NaB) on lung injury. Sepsis-associated lung injury was established in mice by cecal ligation and puncture (CLP). Mice in treatment groups received NaB gavage after surgery. The survival rate, the oxygenation index and the lung wet-to-dry weight (W/D) ratio were calculated respectively. Pulmonary and intestinal histologic changes were observed. The total protein concentration in bronchoalveolar lavage fluid (BALF) was measured, and inflammatory factors in serum and BALF were examined. Diamine oxidase (DAO), lipopolysaccharide (LPS), and surfactant-associated protein D (SP-D) levels in serum and amphiregulin in lung tissue were assessed. Intercellular junction protein expression in the lung and intestinal tissues were examined. Changes in immune cells were analyzed. NaB treatment improved the survival rate, the oxygenation index and the histologic changes. NaB decreased the W/D ratio, total protein concentration, and the levels of proinflammatory cytokines, as well as SP-D, DAO and LPS, while increased the levels of anti-inflammatory cytokines and amphiregulin. The intercellular junction protein expression were improved by NaB. Furthermore, the CD4+/CD8+ T-cell ratio and the proportion of CD4+Foxp3+ regulatory T cells (Tregs) were increased by NaB. Our data suggested that NaB gavage effectively improved the survival rate and mitigated lung injury in CLP mice. The possible mechanism was that NaB augmented CD4+Foxp3+ Tregs and enhanced the barrier function of the gut and the lung.

Outcomes and prognosis of progressive pulmonary fibrosis in patients with antineutrophil cytoplasmic antibody-positive interstitial lung disease.

Approximately one-third of fibrosing interstitial lung diseases exhibit progressive pulmonary fibrosis (PPF), a clinicopathological condition distinct yet resembling idiopathic pulmonary fibrosis (IPF). PPF in ANCA-positive ILD (ANCA-ILD) is poorly documented. To clarify incidence, predictors of PPF in ANCA-ILD, and their prognostic impact, 56 patients with ANCA-ILD were followed for ≥ 1 year (April 2004 to April 2021). PPF was defined per ATS/ERS/JRS/ALAT PPF 2022 guideline. We compared PPF and non-PPF in 38 patients with pulmonary function tests and ≥ 1 year follow up. ANCA-ILD (19 male, 19 female; mean age 72 years) comprised 21 patients with microscopic polyangiitis ILD (MPA-ILD) and 17 with ANCA-positive IP without systemic vasculitis (ANCA-IP). PPF occurred in 15/38 (39.5%) overall, and 27% of patients with MPA-ILD and 53% with ANCA-IP. Patient characteristics did not differ between PPF and non-PPF, however, the survival was significantly worse in patients with PPF than those with non-PPF. On multivariate regression analysis, higher age, higher serum SP-D level, and lower baseline %FVC were associated with PPF. In ANCA-ILD, 39.5% of patients demonstrated PPF, which is associated with increased mortality. Predictors of PPF were older age, higher SP-D, and lower baseline %FVC.

Exogenous Apelin-13 Administration Ameliorates Cyclophosphamide- Induced Oxidative Stress, Inflammation, and Apoptosis in Rat Lungs.

BACKGROUND: Apelin-13 is an endogenous adipocytokine known for its antioxidant, antiinflammatory, and antiapoptotic properties. OBJECTIVE: We aimed to investigate the possible protective effects of exogenous Apelin-13 administration on oxidative stress, inflammation, and apoptosis induced by the cytotoxic agent cyclophosphamide (CP) in the lungs. METHODS: Twenty-four male Wistar albino rats were divided into four groups: Control (saline), CP (200 mg/kg), Apelin-13 (10 µg/kg/day), and CP+Apelin-13. CP was administered as a single dose on the fifth day, and apelin-13 was administered intraperitoneally for five days. Total oxidant status (TOS), total antioxidant status (TAS), and lipid peroxidation were determined with spectrophotometry, TNFα and IL1ß were determined with ELISA, APJ, Sirt1, NF-κB, and p53 mRNA expressions were determined with qRT-PCR, cytochrome (Cyt) C and caspase-3 protein expressions were studied with western blotting in lung tissues. The oxidative stress index (OSI) was also calculated. Furthermore, serum surfactant protein-D (SP-D) and Krebs von den Lungen-6 (KL-6) levels were measured with ELISA. RESULTS: Compared to the control group, TOS, OSI, lipid peroxidation, TNFα, IL1ß, cyt C, caspase-3, APJ, NF-κB, and p53 were higher, and Sirt1 was lower in the lung tissue of rats in the CP group. Serum KL-6 and SP-D levels were higher in the CP group. Co-administration of CP with Apelin-13 completely reversed the changes induced by CP administration. CONCLUSION: Exogenous Apelin-13 treatment protected lung tissue against injury by inhibiting cyclophosphamide-induced oxidative stress, inflammation, and apoptosis. This protective effect of apelin-13 was accompanied by upregulation of the Sirt1 and downregulation of NF-κB/p53 in the lungs.

Correlation of the High-Resolution Computed Tomography Patterns of Intrathoracic Sarcoidosis with Serum Levels of SAA, CA 15.3, SP-D, and Other Biomarkers of Interstitial Lung Disease.

Studies on the serum biomarkers of granulomatous inflammation and pulmonary interstitial disease in intrathoracic sarcoidosis have shown conflicting results. We postulated that differences in the concentrations of serum biomarkers can be explained by the heterogenous patterns of sarcoidosis seen on thoracic HRCT. Serum biomarker levels in 79 consecutive patients, newly diagnosed with intrathoracic sarcoidosis, were compared to our control group of 56 healthy blood donors. An analysis was performed with respect to HRCT characteristics (the presence of lymph node enlargement, perilymphatic or peribronchovascular infiltrates, ground-glass lesions, or fibrosis), CXR, and disease extent. Serum levels of CXCL9, CXCL10, CTO, and CCL18 were statistically significantly increased in all patients compared to controls. Serum levels of CA15.3 were statistically significantly increased in all patients with parenchymal involvement. SAA was increased in patients with ground-glass lesions while SP-D levels were statistically significantly increased in patients with lung fibrosis. Only SP-D and CA15.3 showed a significant correlation to interstitial disease extent. In conclusion, we found that sarcoidosis patients with different HRCT patterns of intrathoracic sarcoidosis have underlying biochemical differences in their serum biomarkers transcending Scadding stages. The stratification of patients based on both radiologic and biochemical characteristics could enable more homogenous patient selection for further prognostic studies.

Early life surfactant protein-D levels in bronchoalveolar lavage fluids of extremely preterm neonates.

Surfactant protein-D (SP-D) is a hydrophilic protein with multiple crucial anti-inflammatory and immunological functions. It might play a role in the development and course of pulmonary infections, acute respiratory distress syndrome, and other respiratory disorders. Only few small neonatal studies have investigated SP-D: we aimed to investigate the links between this protein, measured in the first hours of life in extremely preterm neonates, and clinical outcomes, as well its relationship with pulmonary secretory phospholipase A2 (sPLA2). Bronchoalveolar lavage fluids were obtained within the first 3 h of life. SP-D and sPLA2 were measured with ELISA and radioactive method, respectively; epithelial lining fluid concentrations were estimated with urea ratio. Clinical data were prospectively collected. One hundred extremely preterm neonates were nonconsecutively studied. SP-D was significantly raised with increasing gestational age (24-26 wk: 68 [0-1,694], 27 or 28 wk: 286 [0-1,328], 29 or 30 wk: 1,401 [405-2,429] ng/mL, overall P = 0.03). SP-D was significantly higher in cases with clinical chorioamnionitis with fetal involvement (1,138 [68-3,336]) than in those without clinical chorioamnionitis with fetal involvement (0 [0-900] ng/mL, P < 0.001). SP-D was lower in infants with bronchopulmonary dysplasia (BPD) (251 [0-1,550 ng/mL]) compared with those without bronchopulmonary dysplasia (BPD) or who died before its diagnosis (977 [124-5,534 ng/mL], P = 0.05) and this was also significant upon multivariate analysis [odds ration (OR): 0.997 (0.994-0.999), P = 0.024], particularly in neonates between 27- and 28-wk gestation. SP-D significantly correlated with the duration of hospital stay (ρ = -0.283, P = 0.002), invasive ventilation (ρ = -0.544, P = 0.001), and total sPLA2 activity (ρ = 0.528, P = 0.008). These findings help understanding the role of SP-D early in life and support further investigation about the role of SP-D in developing BPD.NEW & NOTEWORTHY Surfactant protein-D increases with gestational age and is inversely associated with BPD development. These results have been obtained in the first hours of life of extremely preterm neonates with optimal perinatal care.

Respiratory Effects of Traffic-Related Air Pollution: A Randomized, Crossover Analysis of Lung Function, Airway Metabolome, and Biomarkers of Airway Injury.

BACKGROUND: Exposure to traffic-related air pollution (TRAP) has been associated with increased risks of respiratory diseases, but the biological mechanisms are not yet fully elucidated. OBJECTIVES: Our aim was to evaluate the respiratory responses and explore potential biological mechanisms of TRAP exposure in a randomized crossover trial. METHODS: We conducted a randomized crossover trial in 56 healthy adults. Each participant was exposed to high- and low-TRAP exposure sessions by walking in a park and down a road with high traffic volume for 4 h in random order. Respiratory symptoms and lung function, including forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), the ratio of FEV1 to FVC, and maximal mid-expiratory flow (MMEF), were measured before and after each exposure session. Markers of 8-isoprostane, tumor necrosis factor-α (TNF-α), and ezrin in exhaled breath condensate (EBC), and surfactant proteins D (SP-D) in serum were also measured. We used linear mixed-effects models to estimate the associations, adjusted for age, sex, body mass index, meteorological condition, and batch (only for biomarkers). Liquid chromatography-mass spectrometry was used to profile the EBC metabolome. Untargeted metabolome-wide association study (MWAS) analysis and pathway enrichment analysis using mummichog were performed to identify critical metabolomic features and pathways associated with TRAP exposure. RESULTS: Participants had two to three times higher exposure to traffic-related air pollutants except for fine particulate matter while walking along the road compared with in the park. Compared with the low-TRAP exposure at the park, high-TRAP exposure at the road was associated with a higher score of respiratory symptoms [2.615 (95% CI: 0.605, 4.626), p=1.2×10-2] and relatively lower lung function indicators [-0.075L (95% CI: -0.138, -0.012), p=2.1×10-2] for FEV1 and -0.190L/s (95% CI: -0.351, -0.029; p=2.4×10-2) for MMEF]. Exposure to TRAP was significantly associated with changes in some, but not all, biomarkers, particularly with a 0.494-ng/mL (95% CI: 0.297, 0.691; p=9.5×10-6) increase for serum SP-D and a 0.123-ng/mL (95% CI: -0.208, -0.037; p=7.2×10-3) decrease for EBC ezrin. Untargeted MWAS analysis revealed that elevated TRAP exposure was significantly associated with perturbations in 23 and 32 metabolic pathways under positive- and negative-ion modes, respectively. These pathways were most related to inflammatory response, oxidative stress, and energy use metabolism. CONCLUSIONS: This study suggests that TRAP exposure might lead to lung function impairment and respiratory symptoms. Possible underlying mechanisms include lung epithelial injury, inflammation, oxidative stress, and energy metabolism disorders. https://doi.org/10.1289/EHP11139.

A Composite Serum Biomarker Index for the Diagnosis of Systemic Sclerosis-Associated Interstitial Lung Disease: A Multicenter, Observational Cohort Study.

OBJECTIVE: In patients with systemic sclerosis (SSc), we investigated composite serum biomarker panels for the diagnosis and risk stratification of SSc-associated interstitial lung disease (SSc-ILD). METHODS: We analyzed 28 biomarkers in 640 participants: 259 patients with SSc-ILD and 179 SSc patients without ILD (Australian Scleroderma Cohort Study), 172 patients with idiopathic pulmonary fibrosis (IPF-controls) (Australian IPF Registry), and 30 healthy controls. A composite index was developed from biomarkers associated with ILD in multivariable analysis derived at empirical thresholds. We evaluated the performance of the index to identify ILD, and specifically SSc-ILD, and its association with lung function, disease extent on radiography, and patient health-related quality of life in derivation and validation cohorts. Biomarkers to distinguish SSc-ILD from IPF-controls were identified. RESULTS: A composite biomarker index, comprising surfactant protein D (SP-D), Ca15-3, and intercellular adhesion molecule 1 (ICAM-1), was strongly associated with SSc-ILD diagnosis, independent of age, sex, smoking history, and lung function (for biomarker index score 3, pooled adjusted odds ratio was 12.72 (95% confidence interval 4.59-35.21) (P < 0.001). The composite index strengthened the performance of individual biomarkers for SSc-ILD identification. In SSc patients, a higher index was associated with worse baseline disease severity (for biomarker index score 3 relative to biomarker index score 0, the adjusted absolute change in forced vital capacity percent predicted was -17.84% and the diffusing capacity for carbon monoxide percent predicted was -20.16%; both P < 0.001). CONCLUSION: A composite serum biomarker index, comprising SP-D, Ca15-3, and ICAM-1, may improve the identification and risk stratification of ILD in SSc patients at baseline.

[Expression and role of deleted in malignant brain tumor protein 1 in acute respiratory distress syndrome rats induced by sepsis].

OBJECTIVE: To observe the expression of deleted in malignant brain tumor protein 1 (DMBT1) in rat acute respiratory distress syndrome (ARDS) model induced by sepsis and its relationship with ARDS related biomarkers. METHODS: Forty-eight healthy male rats were randomly divided into sham operation group (Sham group) and ARDS model group, and the rats in each group were further divided into three subgroups at 6, 12 and 24 hours after operation, with 8 rats in each subgroup. The rats in the Sham group were exposed to the cecum only, and sepsis induced ARDS model was reproduced by cecal ligation and puncture (CLP) in the ARDS model group. The general performance was observed at 6, 12, 24 hours after operation. Abdominal aortic blood of rats was collected, and the levels of DMBT1, surfactant-associated protein D (SP-D), vascular endothelial growth factor (VEGF), interleukins (IL-6, IL-10) in serum were determined by enzyme-linked immunosorbent assay (ELISA). The lung tissues were collected, and the lung wet/dry weight (W/D) ratio was determined. The lung tissue pathological changes were observed under light microscope after hematoxylin-eosin (HE) staining, and the lung tissue injury score was evaluated. The expression of DMBT1 protein in lung tissue was determined by Western blotting. The relationship between the serum DMBT1 and SP-D, VEGF, IL-6, IL-10, lung tissue injury score were analyzed by Pearson correlation analysis. RESULTS: Rats in the ARDS model group showed obvious pathological manifestations after operation. The alveolar structure destruction, inflammatory cell infiltration, and alveolar hemorrhage were observed under microscope. Compared with the Sham group, the lung tissue injury score and the lung W/D ratio at 12 hours after operation in the ARDS model group were significantly increased (lung tissue injury score: 3.35±0.13 vs. 1.16±0.07, lung W/D ratio: 5.36±0.44 vs. 4.38±0.35, both P < 0.05), and pulmonary edema was present, which suggested that the ARDS model caused by CLP was successfully reproduced. The results of ELISA and Western blotting showed that the levels of serum DMBT1, SP-D, VEGF and IL-6 in the ARDS model group increased gradually with time, while the level of IL-10 increased first and then decreased. Compared with the Sham group, the levels of DMBT1 in serum and the expressions of DMBT1 protein in lung tissue in the ARDS model group were significantly increased from 6 hours after operation [serum (ng/L) : 231.96±19.17 vs. 187.44±10.19, lung tissue (DMBT1/ß-actin): 2.05±0.19 vs. 0.93±0.25, both P < 0.05], and the levels of SP-D, VEGF, IL-6 and IL-10 in serum were significantly increased from 12 hours after operation [SP-D (ng/L): 73.35±8.05 vs. 43.28±5.77, VEGF (ng/L): 89.85±8.47 vs. 43.19±5.11, IL-6 (ng/L): 36.01±2.48 vs. 17.49±1.77, IL-10 (ng/L): 84.55±8.41 vs. 39.83±5.02, all P < 0.05]. Pearson correlation analysis showed that serum DMBT1 was positively correlated with serum SP-D, VEGF, IL-6, IL-10 and lung injury score at 12 hours and 24 hours in the ARDS model group (12 hours: r values were 0.946, 0.942, 0.931, 0.936, 0.748, respectively; 24 hours: r values were 0.892, 0.945, 0.951, 0.918, 0.973, respectively; all P < 0.05). CONCLUSIONS: DMBT1 is a novel early biomarker of ARDS by affecting alveolar epithelial cell, alveolar capillary permeability and inflammatory response.

Intravenous surfactant protein D inhibits lipopolysaccharide-induced systemic inflammation.

BACKGROUND: Surfactant protein D (SP-D) is an innate host defense protein that clears infectious pathogens from the lung and regulates pulmonary host defense cells. SP-D is also detected in lower concentrations in plasma and many other non-pulmonary tissues. Plasma levels of SP-D increase during infection and other proinflammatory states; however, the source and functions of SP-D in the systemic circulation are largely unknown. We hypothesized that systemic SP-D may clear infectious pathogens and regulate host defense cells in extrapulmonary systems. METHODS: To determine if SP-D inhibited inflammation induced by systemic lipopolysaccharide (LPS), E.coli LPS was administered to mice via tail vein injection with and without SP-D and the inflammatory response was measured. RESULTS: Systemic SP-D has a circulating half-life of 6 h. Systemic IL-6 levels in mice lacking the SP-D gene were similar to wild type mice at baseline but were significantly higher than wild type mice following LPS treatment (38,000 vs 29,900 ng/ml for 20 mg/kg LPS and 100,700 vs 73,700 ng/ml for 40 mg/kg LPS). In addition, treating wild type mice with purified intravenous SP-D inhibited LPS induced secretion of IL-6 and TNFα in a concentration dependent manner. Inhibition of LPS induced inflammation by SP-D correlated with SP-D LPS binding suggesting SP-D mediated inhibition of systemic LPS requires direct SP-D LPS interactions. CONCLUSIONS: Taken together, the above results suggest that circulating SP-D decreases systemic inflammation and raise the possibility that a physiological purpose of increasing systemic SP-D levels during infection is to scavenge systemic infectious pathogens and limit inflammation-induced tissue injury.

Circulating markers of neutrophil activation and lung injury in pediatric pneumonia in low-resource settings.

Diagnostic biomarkers for childhood pneumonia could guide management and improve antibiotic stewardship in low-resource settings where chest x-ray (CXR) is not always available. In this cross-sectional study, we measured chitinase 3-like protein 1 (CHI3L1), surfactant protein D (SP-D), lipocalin-2 (LCN2), and tissue inhibitor of metalloproteinases-1 (TIMP-1) in Ugandan children under the age of five hospitalized with acute lower respiratory tract infection. We determined the association between biomarker levels and primary end-point pneumonia, indicated by CXR consolidation. We included 89 children (median age 11 months, 39% female). Primary endpoint pneumonia was present in 22 (25%). Clinical signs were similar in children with and without CXR consolidation. Broad-spectrum antibiotics (ceftriaxone) were administered in 83 (93%). Levels of CHI3L1, SP-D, LCN2 and TIMP-1 were higher in patients with primary end-point pneumonia compared to patients with normal CXR or other infiltrates. All markers were moderately accurate predictors of primary end-point pneumonia, with area under receiver operator characteristic curves of 0.66-0.70 (p<0.05 for all markers). The probability of CXR consolidation increased monotonically with the number of markers above cut-off. Among 28 patients (31%) in whom all four markers were below the cut-off, the likelihood ratio of CXR consolidation was 0.11 (95%CI 0.015 to 0.73). CHI3L1, SP-D, LCN2 and TIMP-1 were associated with CXR consolidation in children with clinical pneumonia in a low-resource setting. Combinations of quantitative biomarkers may be useful to safely withhold antibiotics in children with a low probability of bacterial infection.

Malondialdehyde acetaldehyde adduction of surfactant protein D attenuates SARS-CoV-2 spike protein binding and virus neutralization.

BACKGROUND: Over 43% of the world's population regularly consumes alcohol. Although not commonly known, alcohol can have a significant impact on the respiratory environment. Living in the time of the COVID-19 pandemic, alcohol misuse can have a particularly deleterious effect on SARS-CoV-2-infected individuals and, in turn, the overall healthcare system. Patients with alcohol use disorders have higher odds of COVID-19-associated hospitalization and mortality. Even though the detrimental role of alcohol on COVID-19 outcomes has been established, the underlying mechanisms are yet to be fully understood. Alcohol misuse has been shown to induce oxidative damage in the lungs through the production of reactive aldehydes such as malondialdehyde and acetaldehyde (MAA). MAA can then form adducts with proteins, altering their structure and function. One such protein is surfactant protein D (SPD), which plays an important role in innate immunity against pathogens. METHODS AND RESULTS: In this study, we examined whether MAA adduction of SPD (SPD-MAA) attenuates the ability of SPD to bind SARS-CoV-2 spike protein, reversing SPD-mediated virus neutralization. Using ELISA, we show that SPD-MAA is unable to competitively bind spike protein and prevent ACE2 receptor binding. Similarly, SPD-MAA fails to inhibit entry of wild-type SARS-CoV-2 virus into Calu-3 cells, a lung epithelial cell line, as well as ciliated primary human bronchial epithelial cells isolated from healthy individuals. CONCLUSIONS: Overall, MAA adduction of SPD, a consequence of alcohol overconsumption, represents one mechanism of compromised lung innate defense against SARS-CoV-2, highlighting a possible mechanism underlying COVID-19 severity and related mortality in patients who misuse alcohol.

Surfactant protein D inhibits lipid-laden foamy macrophages and lung inflammation in chronic obstructive pulmonary disease.

Increased levels of surfactant protein D (SP-D) and lipid-laden foamy macrophages (FMs) are frequently found under oxidative stress conditions and/or in patients with chronic obstructive pulmonary disease (COPD) who are also chronically exposed to cigarette smoke (CS). However, the roles and molecular mechanisms of SP-D and FMs in COPD have not yet been determined. In this study, increased levels of SP-D were found in the bronchoalveolar lavage fluid (BALF) and sera of ozone- and CS-exposed mice. Furthermore, SP-D-knockout mice showed increased lipid-laden FMs and airway inflammation caused by ozone and CS exposure, similar to that exhibited by our study cohort of chronic smokers and COPD patients. We also showed that an exogenous recombinant fragment of human SP-D (rfhSP-D) prevented the formation of oxidized low-density lipoprotein (oxLDL)-induced FMs in vitro and reversed the airway inflammation and emphysematous changes caused by oxidative stress and CS exposure in vivo. SP-D upregulated bone marrow-derived macrophage (BMDM) expression of genes involved in countering the oxidative stress and lipid metabolism perturbations induced by CS and oxLDL. Our study demonstrates the crucial roles of SP-D in the lipid homeostasis of dysfunctional alveolar macrophages caused by ozone and CS exposure in experimental mouse emphysema, which may provide a novel opportunity for the clinical application of SP-D in patients with COPD.

Dysregulated serum and seminal plasma levels of surfactant protein D and MCP-1 in men with genital tract infection/inflammation.

PROBLEM: Surfactant protein D (SP-D), a multimeric collectin expressed by testicular mucosal epithelia and is positively regulated by testosterone. It exerts antimicrobial effects, modulates inflammation and rescued spermatogenesis in a murine model. Various cytokines and chemokines, including MCP-1, play a key role in regulating the inflammation in rat and human testis. The study aimed to investigate the role of SP-D and involvement of chemokines and cytokines in the male infertility associated with urogenital infections or inflammation. METHOD OF STUDY: The cross-sectional study evaluated levels of SP-D, testosterone, estradiol and the cytokines/chemokines including MCP-1 in the serum and semen samples of fertile and infertile Indian men with and without urogenital infections/inflammation (n = 76). RESULTS: Both fertile and infertile males with urogenital infection/inflammation had significantly lower levels of SP-D and higher levels of the chemokine, Monocyte chemoattractant protein 1 (MCP-1) in the serum and seminal plasma. Seminal plasma of these males exhibited significantly higher proportion of proteolytically degraded forms of SP-D. The serum SP-D levels positively correlated with testosterone/estradiol (TE) ratio. There was no significant correlation between the SP-D levels in seminal plasma and sperm count/motility. With a significant area under the Receiver Operating Characteristic curves, the serum and seminal plasma SP-D levels exhibited significant potential to predict infertility with high sensitivity and specificity in men with genital infections/inflammation. CONCLUSIONS: The circulating and seminal plasma SP-D levels were decreased in men with urogenital infection and inflammation. This could be due to their engagement at the site of infection, dysregulated expression owing to the altered hormonal profile and increased proteolytic degradation.

Longitudinal analyses and predictive factors of radiation-induced lung toxicity-related parameters after stereotactic radiotherapy for lung cancer.

BACKGROUND AND PURPOSE: The purpose of this prospective study was to investigate changes in longitudinal parameters after stereotactic radiotherapy for lung cancer and to identify possible pretreatment factors related to radiation-induced lung toxicity and the decline in pulmonary function after radiotherapy. MATERIALS AND METHODS: Protocol-specified examinations, including 4-D CT, laboratory tests, pulmonary function tests (PFTs) and body composition measurements, were performed before SRT and at 1 month, 4 months and 12 months after stereotactic radiotherapy. Longitudinal differences were tested by using repeated-measures analysis of variance. Correlations were examined by using the Pearson product-moment correlation coefficient (r). RESULTS: Sixteen patients were analyzed in this study. During a median follow-up period of 26.6 months, grade 1 and 2 lung toxicity occurred in 11 patients and 1 patient, respectively. The mean Hounsfield units (HU) and standard deviation (SD) of the whole lung, as well as sialylated carbohydrate antigen KL-6 (KL-6) and surfactant protein-D (SP-D), peaked at 4 months after radiotherapy (p = 0.11, p<0.01, p = 0.04 and p<0.01, respectively). At 4 months, lung V20 Gy (%) and V40 Gy (%) were correlated with changes in SP-D, whereas changes in the mean HU of the lung were related to body mass index and lean body mass index (r = 0.54, p = 0.02; r = 0.57, p = 0.01; r = 0.69, p<0.01; and r = 0.69, p<0.01, respectively). The parameters of PFTs gradually declined over time. When regarding the change in PFTs from pretreatment to 12 months, lung V5 Gy (cc) showed significant correlations with diffusion capacity for carbon monoxide (DLCO), DLCO/alveolar volume and the relative change in DLCO (r = -0.72, p<0.01; r = -0.73, p<0.01; and r = -0.63, p = 0.01, respectively). CONCLUSIONS: The results indicated that some parameters peaked at 4 months, but PFTs were the lowest at 12 months. Significant correlations between lung V5 Gy (cc) and changes in DLCO and DLCO/alveolar volume were observed.