Neurotrophin system activation in bronchoalveolar lavage fluid immune cells in pulmonary sarcoidosis.

BACKGROUND AND AIM OF THE STUDY: Pulmonary sarcoidosis is a chronic granulomatous disease characterized by macrophage and CD4+ T-cell accumulation at the site of inflammation. Analysis of the cytokine network has substantially improved knowledge on immunopathogenesis of sarcoidosis. We hypothesize that neurotrophins (NTs), nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and NT-3, besides their importance in immune system activities, participate in chronic inflammatory disorders and in repair processes. METHODS: The expression of NTs and NT receptors was assessed in broncho alveolar lavage (BAL) macrophages, CD4 and CD8 T-cells, from 10 patients with pulmonary sarcoidosis, using molecular biology, Western blotting and immunocytochemistry. RESULTS: Increased levels of NTs and of high affinity NT receptor (Trks) transcripts and proteins in BAL macrophages, CD4+ and CD8+ T-cells from pulmonary sarcoidosis patients were demonstrated in comparison with healthy controls. Contrarily to healthy controls, in pulmonary sarcoidosis the expression of NGF was increased in alveolar macrophages as well as NGF and BDNF in CD4+ and CD8+ T-cells. An increased expression of TrkA, TrkB and TrkC receptors was also noticeable. Furthermore, BDNF expression in alveolar macrophages and NT-3 expression in the three different BAL immune cell populations investigated were induced during sarcoidosis. A significant correlation was observed between CD4:CD8 ratio, lymphocytosis, radiological stage and CD4 and CD8 NT expression. CONCLUSIONS: These findings suggest that NTs are exaggeratedly expressed in BAL immune cells in pulmonary sarcoidosis and may participate in the progression of disease modulating immune cell functions.

Reversibility test in the early stages of bronchial asthma.

In the early stages of bronchial asthma, it is frequent to find subjects with a positive history and an FEV1 or FEV1/FVC > 80% of the predicted value. This study investigated if the test of reversibility showed a reversible airway obstruction (RAO) in 291 subjects with the above clinical and functional features. Forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and expiratory flows (PEF, MEF50, FEF(25-75)) were registered before and 20 minutes after salbutamol administration (200 mcg by MDI). Of 291 subjects, FEV1 increased in 73 (25%) after bronchodilator > or = 12% compared to baseline; the number of subjects with a > or = 35% increase in MEF50 or FEF(25-75) were similar in terms of percentage (respectively, 29.2% and 29%), whereas those with increases in FVC (> or = 12%) and in PEF (> or = 15%) were significantly lower (respectively, 2.7% and 12.3%). The percentage of subjects with RAO (FEV1 increase after bronchodilator > or = 12%) was lower (12%) in the subgroup (108 subjects), with an MEF50 > or = 70% of the value predicted at the baseline assessment, and higher (36%) in the subjects of the subgroup (183 subjects) with an MEF50 < 70%. In conclusion, it is advisable to carry out reversibility tests in all subjects with symptoms indicative of asthma even if their functional tests are "normal" because in a considerable number of cases the RAO was found to confirm the suspected diagnosis and provided a more reliable classification of the disease.

Time intervals (3' or 5') between dose steps can influence methacholine challenge test.

Bronchial hyperresponsiveness (BHR) is a common feature in the majority of asthmatic subjects and methacholine is the most frequently used agent for the test. The influence of 3 or 5 min time intervals between doses steps in a double methacholine challenge test (MCH-3' or MCH-5') was investigated. Using the MCH-3' challenge, 52 intermittent asthmatics were classified as having moderate (BHR-M; 18 subjects), mild (BHR-m; 19 subjects), or bordeline (BHR-B; 15 subjects) BHR. The cumulative dose and the PD20FEV(1) were higher for MCH-5' compared with MCH-3' in BHR-m (p < 0.05) and BHR-B (p < 0.05) but not in the BHR-M group. Also the dose response slopes, FEV(1)% decline/cumulative methacholine dose, calculated for the two challenge tests were statistically different only in BHR-m (p < 0.05) and BHR-B (p < 0.01). At MCH-5', there were 16 subjects with BHR-M, 18 with BHR-m, 12 with BHR-B and 6 subjects with normal reactivity. Results may suggest that in the group of BHR-m and BHR-B subjects, at MCH-5' compared with MCH-3', the cumulative effect of the administered drug, quickly metabolized by cholinesterase, is not complete, thus leading to an incorrect estimation of bronchial hyperresponsiveness degree. It is hoped that time interval between doses be standardized to ensure maximum comparability within and between subjects in challenge tests.

Pulmonary alveolar microlithiasis: report on 576 cases published in the literature.

BACKGROUND AND AIM OF THE WORK: Pulmonary alveolar microlithiasis (PAM) is a rare disease characterized by intra-alveolar calcium deposits. The etiology of the disease is still unknown and many authors have supposed that an inherited local enzymatic defect is responsible for calcium deposition. The present paper aimed to study the disorder throughout the world, emphasizing the diagnostic and therapeutic views. METHODS: All the papers published on this subject in the literature were reviewed. RESULTS: Cases studied were 576 and most of them came from Europe (42.7%) and Asia (40.6%). The countries involved were fifty-one and twelve of them were attributed with at least ten cases each (Bulgaria, France, Germany, India, Italy, Poland, Spain, Russia, Japan, Turkey, USA, ex-Yugoslavia). Symptoms were absent in more than half the patients; dyspnoea, cough and chest pain were reported in the other cases. Family history for the disease was found in one-third of the patients. Chest x-rays and computed tomography were so characteristic that they were enough to diagnose the disease even if microscopic evidence of the microliths into the alveoli was obtained in most cases (e.g. by biopsy, autopsy, bronchoalveolar lavage). Pulmonary tuberculosis or sarcoidosis were misdiagnosed in 88 cases out of the 576. The course of the disease was slow and patients usually died as a result of cardio-respiratory failure. CONCLUSIONS: This review of PAM has shown that the etiology of the disease is still unknown, it is widespread throughout the world and easy to diagnose; it develops slowly and therapy is ineffective except for lung transplantation.

Elevated neurotrophin and neurotrophin receptor expression in spontaneously hypertensive rat lungs.

Spontaneously hypertensive rats represent a widely used animal model of hypertension. Altered neurotrophin regulation has been related to systemic hypertension. Lung cells synthesize and release neurotrophins(NT) which are involved in several pulmonary disturbances. Our study explored the expression of NT and their receptors using molecular biology and immunohistochemistry. Spontaneously 6-, 20- and 29- weeks hypertensive (SHR) and Wistar Kyoto rat (WKY) lungs were used. SHR and WKY lungs expressed neurotrophin and neurotrophin receptor mRNAs and protein transcripts. Age and hypertension dependent increase was clearly noticeable. Furthermore, immunohistochemistry revealed that their increase was mainly noticeable within bronchial and vascular components of the lung. Although the role of NT in sympathetic hyperinnervation and progression of systemic hypertension is a well established phenomenon, their increase in SHR lungs, strongly suggest that NT may be operative during pulmonary hypertension and in subsequent airway and pulmonary vascular remodeling.

Neurotrophin and neurotrophin receptor protein expression in the human lung.

Neurotrophins (NTs) promote survival and differentiation of central and peripheral neurons, and display several activities also in non-neuronal cells. Human lungs synthesize and release NTs, which are probably involved in the pathophysiology of pulmonary disturbances. In this article the expression and anatomic localization of nerve growth factor, brain-derived neurotrophic factor, and NT-3 and of corresponding high-affinity receptors TrkA, TrkB (full-length and truncated [TR-] isoforms), TrkC, and of the low-affinity p75 receptor, were assessed in surgical samples from adult human lung by reverse transcriptase-polymerase chain reaction, Western blot, and immunohistochemistry. NTs and their cognate receptor mRNA and protein transcripts were detected by reverse transcriptase-polymerase chain reaction and immunoblotting, respectively, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) mRNA and corresponding protein transcripts being the most expressed. High levels of TrkB-[TR-] mRNA and of its protein transcript were also demonstrated, whereas a low expression of p75 mRNA and of corresponding protein transcript were found. Microanatomic analysis of immunohistochemical study revealed that bronchial epithelial cells were immunoreactive for different NTs, with a higher intensity of BDNF immune staining compared with other NTs, but did not express NT receptor immunoreactivity. Alveolar cells were immunoreactive for TrkA and TrkC receptor protein, but did not display immunoreactivity for NTs or other receptors investigated. Gland cells expressed NT and high-affinity NT receptor immunoreactivity, but not p75 receptor immunoreactivity. NT and low-affinity receptor immunoreactivity was observed within neurons and satellite cells of parasympathetic ganglia as well as in nerve fiber-like structures supplying the bronchopulmonary tree. An obvious immunoreactivity for NTs and NT receptor protein was also observed in intrapulmonary branches of pulmonary artery. Pulmonary lymphocytes and macrophages express nerve growth factor and high-affinity NT receptor immunoreactivity. The role of NTs in non-neuronal tissue including lung has not been clarified yet. The widespread expression of NTs and their receptors in different components of the lung suggests that these factors may contribute to regulate cell function in human lung.

Expression of peripheral blood lymphocyte muscarinic cholinergic receptor subtypes in airway hyperresponsiveness.

The expression of muscarinic cholinergic receptor subtypes was investigated in peripheral blood lymphocytes (PBL) of bronchial asthma patients by a combined kinetic and equilibrium labeling technique for radioligand binding assay of muscarinic cholinergic receptor subtypes and by receptor immunochemistry and immunocytochemistry. An increased expression of M2 and to a lesser extent of M5 receptors and no changes of M4 receptor were observed in PBL of asthmatics compared to control individuals. The increase was related to bronchial hyperresponsiveness detected by methacholine challenge test. Analysis of M3 receptor expression revealed biphasic changes, with a decreased receptor density in patients with normal, mild and moderate responses to methacholine test and a recovery to levels similar to those found in healthy individuals in severe responders to methacholine test. The demonstration of a different expression of lymphocyte muscarinic receptors in asthma suggests that cholinergic system may participate to a molecular framework influencing immune functions in asthma.