Kinetics of plasma SPB and RAGE during mechanical ventilation in patients undergoing major vascular surgery.

Receptor-of-Advanced-Glycation-End-products (RAGE) and Surfactant-Protein-type-B (SPB) are reported as lung injury markers. Unlike SPB, RAGE is secreted by several tissues, so that RAGE specificity as lung injury marker is questionable. We measured SPB and RAGE in 19 patients undergoing major vascular abdominal surgery. SPB and RAGE were measured before mechanical ventilation (T0), at 1st (T1), 2nd (T2) and, when present, 3rd (T3) hour of mechanical ventilation, and 1h after extubation (T(POST)). Last data during mechanical ventilation, either T2 or T3, are reported as T(END). SPB and RAGE values were normalized for total protein (SPB(N) and RAGE(N)). SPB(N) and RAGE(N) increments from T0 to T(END) were 56.2 [39.1] ng/mg (mean [75-25 percentile]) and 10.6[7.1] pg/mg, respectively. SPB values increased progressively during mechanical ventilation, whereas RAGE values increased at T(1) but not thereafter. SPB(N) increase (T(END)-T0), but not RAGE(N), was related to ΔPaO(2)/FiO2 changes during mechanical ventilation (r=0.575, p=0.01). Plasma RAGE(N) and SPB(N) kinetics in patients undergoing major vascular surgery are different.

Proteína surfactante tipo B en la insuficiencia cardiaca crónica: un examen de la barrera alveolocapilar / No disponible

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Proteína surfactante pulmonar tipo B en circulación periférica y deterioro funcional en pacientes con insuficiencia cardiaca crónica / Pulmonary Surfactant Protein B in the Peripheral Circulation and Functional Impairment in Patients With Chronic Heart Failure

Introducción y objetivos. La proteína surfactante tipo B (PS-B) es un marcador de daño en la barrera alveolocapilar y podría ser útil en la monitorización del deterioro pulmonar asociado a la insuficiencia cardiaca crónica (ICC). Métodos. Se estudió a 43 pacientes ambulatorios con ICC (edad, 51 ± 10 años; el 77% varones; fracción de eyección del ventrículo izquierdo [FEVI], 33% ± 11%) a los que se realizó una prueba de esfuerzo cardiopulmonar limitada por disnea. Se obtuvieron muestras de sangre periférica en reposo y en el primer minuto tras el máximo esfuerzo. La presencia y la cantidad de PS-B en suero sanguíneo se analizaron mediante análisis Western blot. Resultados. En reposo, se detectó PS-B circulante en 35 (82%) pacientes, frente a sólo 6 (23%) voluntarios sanos de una muestra control (n = 26; edad, 51 ± 10 años; el 77% varones), con mayores concentraciones circulantes en pacientes con ICC (mediana [intervalo intercuartílico], 174 [70-283]) frente al grupo control (77 [41-152]; p < 0,001). En pacientes con ICC, la presencia de PS-B circulante se asoció a una menor FEVI (31,4% ± 9,6% frente a 41,8% ± 15%; p = 0,01). Tras el ajuste multivariable, la cantidad de PS-B en reposo se correlacionó con una mayor pendiente VE/VCO2 (β = 1,45; p = 0,02). Los valores de PS-B en el esfuerzo máximo se correlacionaron casi perfectamente con las cifras en reposo (r = 0,980; p < 0,001), pero no se incrementaron significativamente con el esfuerzo (p = 0,164) ni se correlacionaron con los parámetros de ejercicio. Conclusiones. En pacientes con ICC, la proteína surfactante pulmonar tipo B está incrementada en la circulación periférica y se correlaciona con la ineficiencia ventilatoria en el ejercicio expresada como pendiente VE/VCO2

Introduction and objectives. Surfactant protein B (SP-B) is a marker of damage to the alveolar-capillary barrier that could be useful for monitoring functional impairment in patients with chronic heart failure (HF). Methods. Dyspnea-limited cardiopulmonary exercise testing was carried out in 43 outpatients with chronic HF (age 51±10 years, 77% male, left ventricular ejection fraction [LVEF] 33±11%). Peripheral blood serum samples were obtained at rest and during the first minute of peak exercise. The presence and concentration of SP-B in the serum samples were determined by Western blot analysis. Results. At rest, SP-B was detected in 35 (82%) patients compared with only six (23%) healthy volunteers in a control group (n=26, age 51±10 years, 77% male). The median circulating SP-B level was higher in HF patients, at 174 [interquartile range, 70-283] vs. 77 [41-152] (P<.001) in the control group. In HF patients, the presence of circulating SP-B was associated with a lower LVEF (31.4±9.6% vs. 41.8±15%; P=.01). Multivariate analysis showed that the resting SP-B level correlated with a greater VE/VCO2 slope (β=1.45; P=.02). The peak-exercise SP-B level correlated almost perfectly with the resting level (r=0.980; P<.001), but there was no significant increase with exercise (P=.164). Nor was there a correlation with any other exercise parameter. Conclusions. In patients with chronic HF, the level of pulmonary surfactant protein B in the peripheral circulation is increased and is correlated with ventilatory inefficiency during exercise, as indicated by the VE/VCO2 slope

Bronchoalveolar lavage surfactant protein a, B, and d concentrations in preterm infants ventilated for respiratory distress syndrome receiving natural and synthetic surfactants.

Surfactant proteins (SPs) play an important role in surfactant metabolism and function. Understanding their relative contribution to clinical outcome remains incomplete. Exogenous surfactants differ in their SP content and physiologic effects. The aims of this study were to measure bronchoalveolar lavage (BAL) SP concentrations from preterm infants ventilated for respiratory distress syndrome and to assess their association with clinical outcome. Fifty preterm infants randomized to receive a natural or synthetic surfactant were lavaged each day for the first week and twice weekly thereafter using a standardized nonbronchoscopic technique. BAL SP-A, SP-B, and SP-D concentrations were measured using ELISA. Median BAL SP-A, SP-B, and SP-D concentrations for the whole cohort rose significantly during the first postnatal week (p < 0.05). SP-A concentration did not differ between outcome groups. BAL SP-B concentration rose significantly in lungs that were not supplemented with SP-B. Infants dying had significantly lower BAL SP-B concentrations on d 2 and 6 compared with survivors. BAL SP-D concentrations were significantly lower on d 2 and 3 among infants in supplemental oxygen on d 28 compared with those in air. BAL SP-A and SP-D concentrations did not differ significantly between infants randomized to receive a natural or synthetic surfactant. Lower BAL SP-B and SP-D but not SP-A concentrations were associated with worse clinical prognosis.

Component-specific surface and physiological activity in bovine-derived lung surfactants.

Composition, surface activity and effects on pressure-volume (P-V) mechanics are examined for lavaged calf lung surfactant (LS) and the clinical exogenous surfactants Infasurf and Survanta. Lavaged LS and Infasurf had closely-matching compositions of phospholipids and neutral lipids. Survanta had higher levels of free fatty acids and triglycerides consistent with its content of added synthetic palmitic acid and tripalmitin. Infasurf and Survanta both contained less total protein than LS because of extraction with hydrophobic solvents, but the total protein content relative to phospholipid in Survanta was about 45% lower than in Infasurf. This difference was primarily due to surfactant protein (SP)-B, which was present by ELISA at a mean weight percent relative to phospholipid of 1.04% in LS, 0.90% in Infasurf, and 0.044% in Survanta. Studies on component fractions separated by gel permeation chromatography showed that SP-B was a major contributor to the adsorption, dynamic surface activity, and P-V mechanical effects of Infasurf, which approached whole LS in magnitude. Survanta had lower adsorption, higher minimum surface tension, and a smaller effect on surfactant-deficient P-V mechanics consistent with minimal contributions from SP-B. Addition of 0.05% by weight of purified bovine SP-B to Survanta did not improve surface or physiological activity, but added 0.7% SP-B improved adsorption, dynamic surface tension lowering, and P-V activity to levels similar to Infasurf. The SP-B content of lung surfactants appears to be a crucial factor in their surface activity and efficacy in improving surfactant-deficient pulmonary P-V mechanics.