Effect of glucocorticoids on stem cell factor expression in human asthmatic bronchi.

BACKGROUND: Stem cell factor (SCF) is a major mast cell growth factor promoting differentiation, chemotaxis as well as inhibition of apoptosis of mast cells. Regulation of SCF expression by glucocorticoids has not yet been reported in human asthmatic bronchi. OBJECTIVE: To evaluate SCF mRNA and protein expression in biopsy specimen and bronchoalveolar lavage fluid, respectively, and to determine the mast cell numbers in biopsy sections from control and asthmatic subjects treated or not with glucocorticoids. METHODS: Volunteers were recruited out of pollen season. Asthmatic patients were allergic to common allergen extracts including grass and tree pollen, cat, dog or mite; three volunteers had non-allergic asthma. Mast cell numbers were counted after anti-human tryptase immunolabelling. SCF mRNA was quantified by real-time fluorescent PCR (LightCycler) after reverse transcription, and SCF protein was measured by ELISA. RESULTS: Asthmatic patients not treated with glucocorticoids showed a 5.8-, 1.8- and 3.1-fold significant increase in SCF mRNA, protein levels and mast cell numbers, respectively, compared with healthy volunteers of the control group (7.8 and 1.3 pg/mug SCF mRNA/GAPDH; 99.8+/-11.5 and 56.0+/-11.0 pg/mL SCF protein; 103+/-21 and 33+/-8 mast cells/mm(2), respectively; P<0.05). In asthmatic patients treated with glucocorticoids, a significant decrease of SCF mRNA, protein levels and mast cell numbers was observed as compared with untreated asthmatic patients (1.1 pg/microg mRNA; 62.0+/-10.3 pg/mL SCF protein and 39+/-13 mast cells/mm(2); P<0.05), reaching levels comparable to those of the control group. CONCLUSION: Our study shows that SCF is expressed in the bronchus in humans in vivo. This expression is increased in asthma, and is parallel to the increased mast cell numbers in the airways. Both increases were normalized in glucocorticoid-treated patients, strongly suggesting an involvement of SCF in the mast cell-associated asthmatic disease.

Impairment of beta chemokine and cytokine production in patients with HIV related Pneumocystis jerovici pneumonia.

BACKGROUND: Pneumocystis jerovici pneumonia (PJP) remains a frequent opportunistic infection in HIV infected patients which markedly upregulates HIV replication by mechanisms so far poorly elucidated. PJP triggers the production of proinflammatory mediators with activating effects on HIV. However, anti-inflammatory factors with inhibiting effects on HIV are normally produced in parallel. We postulated that an imbalance of mediators normally controlling HIV replication could underlie its marked increase during PJP. METHODS: The production of tumour necrosis factor alpha (TNFalpha), interleukins IL-6 and IL-10, and beta-chemokine by bronchoalveolar lavage (BAL) cells recovered from HIV infected patients with and without PJP was compared. The pulmonary viral load was determined and correlations with cytokine and chemokine production were examined. RESULTS: TNFalpha and IL-6 release was similar in patients with and without PJP but IL-10 and beta-chemokine release was markedly lower in the PJP group (IL-10: p<10(-2), RANTES, MIP-1alpha and MIP-1beta: p<0.001). The pulmonary viral load was markedly higher in patients with PJP (p<0.001) and correlated negatively with levels of MIP-1alpha, RANTES and IL-10 in BAL fluid cells (p<0.05). CONCLUSION: Pulmonary IL-10 and beta-chemokine production is markedly defective in HIV infected patients with PJP, while pulmonary TNFalpha and IL-6 levels are normal. The resulting excess of these latter factors, which are known to upregulate HIV replication, might contribute to the increase in pulmonary viral load and to the more rapid HIV disease progression observed in patients with PJP.

Human alveolar macrophage subpopulations isolated on discontinuous albumin gradients: functional data in normals and sarcoid patients.

Cells recovered by bronchoalveolar lavage from seven normals and seven sarcoid patients were centrifuged on discontinuous bovine albumin (BSA) gradients to study alveolar macrophage (AM) heterogeneity. The gradient was made with nine BSA concentrations from 8 to 30%. After centrifugation, the cells were recovered from the nine interfaces, named a to i. The majority of the AM was recovered from layers b to g. Regulatory activity of AM subpopulations was tested on mitogen-induced blood mononuclear cells (BMC) proliferation: autologous BMC were cocultured with AM from the different layers; 16-h culture supernatants of AM subfractions were added to allogeneic BMC cultures from normal donors. In the autologous assay, AM from the middle layers exhibited a stimulatory activity in normals and even more in sarcoid patients, while AM from the upper layers showed an inhibitory activity in normals but a stimulatory activity in sarcoid patients. In the allogeneic assay, a suppressive effect was found in culture supernatants from normal AM. On the other hand, in sarcoid patients, culture supernatants were less inhibiting, but the inhibitory activity was in both cases maximal in b. These results confirm functional heterogeneity of human AM, and demonstrate that the AM subpopulations differ between normals and sarcoid patients.

Human alveolar macrophage subpopulations isolated on discontinuous albumin gradients. Cytological data in normals and sarcoid patients.

Cells recovered by bronchoalveolar lavage (BAL) from ten subjects (five normals and five sarcoid patients) were centrifuged on discontinuous albumin gradients to study alveolar macrophage (AM) heterogeneity. The gradient was made with nine bovine albumin concentrations (from 8 to 30%). After centrifugation (4000 X g) cells were recovered from the interfaces. The majority of AM was recovered in upper and medium layers with AM purity reaching 90-100% in upper layers, while lymphocytes and granulocytes were found in lower layers. Alveolar macrophage morphology was different along the gradient. Large cytoplasmic vacuoles were found in AM from upper layers. Alveolar macrophage cytoplasmic diameters decreased from the top to the bottom of the gradient, but AM from sarcoid patients appeared larger than AM from normals. Alveolar macrophage nucleo-cytoplasmic ratios increased from top to bottom, but were lower in sarcoid patients than in normals. Alveolar macrophage peroxidase activity was rare (0.5-2% of AM) but reached a higher proportion in upper and lower layers.

[Metabolic acidosis and intravenous injections of fat emulsions (role of phospholipids. Experimental study)]. / Acidose métabolique et injection intra-veineuse d'émulsions lipidiques (role des phospholipides. Etude expérimentale)

In explanation of metabolic acidosis during parenteral nutrition, the authors considered the supply of H+ ions by fat emulsion, containing phospholipids of egg or soy. During intravenous infusions of 24 grams of lecithins to two healthy subjects, they observed an increased output H+ ions in urine, about 74,05 and 75,88 mEq, and a metabolic acidosis of the plasma. The theorically forcasted supply of production was 74,6 mEq. Indeed the metabolism of phospholipids supplies phosphoric ions (PO4H3), giving H+ ions at pH 7,40. The most used fat emulsions are able to give between 37 (intralipid 10%) and 61 (lipihysan 15%) mEq of H+ ions/liter.