Pulmonary function and blood gases after gastric bypass and lifestyle intervention: a comparative study.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Impaired lung function associated with obesity improves with weight loss. WHAT THIS STUDY ADDS: This is the first study to compare the effects of obesity surgery and intensive lifestyle intervention on pulmonary function and arterial blood gases. Arterial oxygenation and pulmonary function improved to a greater extent after gastric bypass than after lifestyle intervention. The superiority of surgical treatment might be mediated by greater weight loss after gastric bypass. Impaired lung function associated with obesity improves with weight loss. The effects of obesity surgery and intensive lifestyle intervention on pulmonary function and arterial blood gases have not previously been subjected to comparative examination. In this 1-year non-randomized controlled clinical trial (ClinicalTrials.gov identifier NCT00273104), 139 morbidly obese subjects (19-66 years, mean [standard deviation] body mass index [BMI] 45.1 kg m(-2) [5.6], 107 women) were treated with either Roux-en-Y gastric bypass surgery (n = 76) or intensive lifestyle intervention (n = 63). Mean weight reduction was 30 (8)% and 8 (9)%, respectively. Dynamic and static lung volumes, gas diffusing capacity and arterial blood gases were measured. Compared with lifestyle intervention, surgery resulted in a significantly greater increase in forced vital capacity (mean [95% confidence interval] between-group difference, 7 [4-10]%), forced expiratory volume in 1 s (7 [5-9]%), total lung capacity (5 [1-8]%), vital capacity (7 [4-9]%), functional residual capacity (18 [12-24]%), expiratory reserve volume (48 [30-66]%) and partial pressure of oxygen in arterial blood (0.5 [0.0-1.0] kPa). These associations either disappeared or diminished after adjusting for weight loss. Reduced central adiposity (waist circumference and waist-to-hip ratio) and systemic inflammation (C-reactive protein and adiponectin) had no effect on pulmonary function beyond the effect of reduced general adiposity (BMI). In morbidly obese subjects, gastric bypass surgery is more effective than lifestyle intervention at improving arterial oxygenation and pulmonary function. The effect might be mediated by greater weight loss after surgical treatment.

Medium conditioned for 24 hours by mononuclear human blood cells contains an inducer of granulopoiesis lacking colony stimulating activity.

Regulation of granulocyte and macrophage formation was studied by a modified CFU-C assay. Mouse bone marrow cells were cultured in methylcellulose in vitro. After colony counting on d 7, the cells were washed out to determine the total cell number per plate, and the distribution of granulocytes and macrophages in smears. By this procedure it was possible to study pathway-specific regulators. The colony stimulating factor in medium conditioned by mouse L-cells appeared specific for the macrophage cell line; 99% of the colony cells were macrophages. Medium conditioned for 24 h by mononuclear cells from human blood, had no colony forming capacity, but increased colony size and generated significant granulocyte production when combined with L-CSF. This granulopoiesis inducing factor was thermo-labile, and was mostly retained by an Amicon filter separating molecules at 100 000 daltons.

Inhibitory effects of plasma from uraemic patients on human mononuclear phagocytes cultured in vitro.

Human mononuclear phagocytes were cultured in plasma from uraemic patients. The presence of uraemic plasma during the engulfment or digestion of 125I-labelled Candida albicans did not inhibit these functions in mononuclear phagocytes cultured for 8 days under normal condition. When normal human macrophages were cultured in the presence of uraemic plasma for 2-4 days, a marked detachment of the cells from the glass coverslips was registered. The phagocytic function of the remaining cells was impaired. Creatinine, urea and methylguanidine in concentrations higher than those usually measured in plasma from uraemic patients did not influence the functional properties of the cells. The inhibitory effect of uraemic plasma on the mononuclear phagocytes is suggested as an explanation for the increased frequency of infections in uraemic patients.

Phagocytosis of heat-killed radiolabelled mycobacteria in human mononuclear phagocytes cultured in vitro.

Human mononuclear phagocytes cultured in vitro for 8 dyas were exposed to 125I-labelled, heat-killed Mycobacterium triviale. The microorganisms were apparently engulfed, but no digestion occurred within a period of 16 days after the engulfment, measured as release of radioactivity to the medium and observed microscopically. Attempts were made to stimulate intracellular digestion of the bacteria. Pre-incubation with BCG-stimulated lymphocytes or with supernatants from BCG-stimulated lymphocyte cultures did not increase the digestive ability of the cells. However, pre-incubation with BCG-stimulated lymphocytes or with supernatants caused detachment of the cells during the following digestion period, probably due to a cytotoxic effect of autologous, transformed lymphocytes on macrophages. When the macrophages were cultured in the presence of autologous lymphocytes and BCG, a similar effect was found.

Effect of sodium-salicylate on the function of cultured, human mononuclear cells.

The in vitro effect of Na-salicylate on some functions of human mononuclear cells was studied. In therapeutical concentrations the drug was found to interfere both the function of lymphocytes and monocytes/macrophages. Na-salicylate in concentrations of 400-800 mug/ml slightly inhibited the digestion of yeast particles. When the drug was present in the culture medium in doses above 160 mug/ml during the cell differentiation period from 90 minutes to the 8th day of culture, a reduction in the number of adhesive, viable cells was recorded. The remaining cells, however, were found to have a normal phagocytic function. A strong and dose dependent inhibition of the ability of lymphocytes to proliferate after antigenic stimulation with BCG bacilli was recorded. The inhibitory effect on the PHA response, however, was less prominent. The results presented indicate that Na-salicylate has a direct inhibitory effect on lymphocyte proliferation and monocyte differentiation and phagocytosis, which may be part of the explanation of the anti-inflammatory effect of the drug.

Effect of aurothiomalate on human mononuclear blood cells cultured in vitro.

Human mononuclear phagocytes were exposed to aurothiomalate in various concentrations and at various stages in the differentiation from monocytes to macrophages in vitro. Monocytes exposed to aurothiomalate during the first 90 minutes of culture showed impaired engulfment capacity when tested 8 days after the exposure to the drug. It was found that aurothiomalate suppressed the digestion capacity in differentiated macrophages while the engulfment capacity was unaffected by the drug. During the period of differentiation from 90 minutes to 8 days of culture, exposure to aurothiomalate resulted in a dose dependent reduction in cell survival and differentiation. The effect of aurothiomalate on the blastoid transformation of lymphocytes following BCG stimulation was also tested. A strong and dose dependent inhibition of DNA synthesis was recorded. The inhibition of phagocytosis in mononuclear phagocytes and the inhibition of antigen-induced lymphocyte stimulation as demonstrated may help to explain the effect of aurothiomalate in patients suffering from rheumatoid arthritis.

The effect of steroids on differentiation and function of cultured, mononuclear cells.

When monocytes had differentiated to macrophages during 8 days of culture in vitro without being exposed to steroids, neither the engulfement nor the digestion step of phagocytosis was found to be influenced by cortisol or the other steroids tested. This indicates that cortisol has no direct effect on the phagocytic function of macrophages in doses below 10(-1) mg/ml. Continuous exposure to cortisol during the period of differentiation resulted in a dose dependent inhibition of the differentiation of monocytes to macrophages. Testosterone, deoxycorticosterone and tetrahydrocortisol in concentration of 10(-1) mg/ml, tested in the same way were found to be toxic to the cells. In lower concentrations, however, these steroids were found to have no effect on the cultured cells. The impaired differentiation of monocytes is suggested as an additional explanation of the reduced number of macrophages appearing at the site of inflammation during cortisol treatment.

The effect of steroids on adhesiveness, rosette-forming ability and survival of cultured, human mononuclear cells.

The effect of different steroids on human mononuclear blood cells during the first 90 minutes of culture in vitro was tested. Cortisol and testosterone were found to increase the ability of lymophocytes to adhere on plastic surfaces. None of the other steroids tested exhibited this effect. Cortisol and corticosterone were found to reduce the number of surviving macrophages in the culture dishes, tested 4 to 8 days after the exposure to the drugs. No lysis of mononuclear cells could be detected following addition of cortisol in doses up to 10(-1) mg/ml. The findings support the previous statements that human lymphocytes are more cortisol-resistant than those of mouse, rat and rabbit.