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EVALUATION OF AIRWAY INFLAMMATION:BRONCHOSCOPY Assoc. Prof. Dr. Murat SEZER Vakıf Gureba Training and Research Hospital
Bronchoscopy • In the early 1970s, Reynolds and Newball were among thefirst to report their experience with fiberopticbronchoscopyand “bronchial” (bronchoalveolar) lavage (BAL) in order toobtain respiratory cells and secretions from human volunteersfor in vitro analysis. Reynolds HY, Newball HH. J LabClin Med 1972; 84:559–73 • However, it was not until approximately10 years later that studies were initiated in subjects withasthma Godard PJ, Chaintreuil M, Damon M,et al. JAllergy Clin Immunol 1982; 70:88–93
Bronchoscopy • BAL • Endobronchial brushing • Forceps biopsy • Transbronchial biopsy made it possible to evaluate the inflammation and remodelling within the lungs
Bronchoscopy • These bronchoscopic studies let us have in vivo information about • The role of inflammatory cells and mediators that play a role in asthma, • The severity of the disease
Bronchoscopy • Studies in asthmatic patients revealed that there is a correlation between inflammatory cell infiltration, activation state of the released cytokines and physiological parameters. Kraft M, Djukanovic R, Wilson S, et al. Am J Respir Crit Care Med 1996; 154: 1505-10 Kavuru MS, Dweik RA, Thomassen MJ. Clin Chest Med 1999; 20: 153-89
Bronchoscopy • The interventional studies also gather new information that can highlight the efficacy of current therapies and their mechanisms of action Djukanovic R, Wilson JW, Britten KM, et al. Am Rev Respir Dis 1992; 145: 669-74 Jeffery PK, Godfrey RWA, Adelroth E, et al. Am Rev Respir Dis 1992; 145: 890-9 Anonymous. J Allergy Clin Immunol 1991; 88: 808-14
Bronchoscopy • These studies increased our knowledge about • Pathophysiology of the allergic asthma and allergic rhinitis • Similarities and differences of the airway • Histology of the subtypes of persisting asthma Busse WW, Wanner A, Adams K, et al. Am J Respir Crit Care Med 2005; 807: 16
Bronchoalveolar Lavage • Generally it is well tolerated but it can cause a decline in pulmonary function tests • BAL alone or together with other procedures do not significantly change the existing tissue inflammation, airway obstruction and airway hyperresponsiveness Krug N, Teran LM, Redington AE, et al. Am J Respir Crit Care Med 1996; 53: 1391-7 Van Vyve T, Chanez P, Bousquet J, et al. Am Rev Respir Dis 1992; 46: 116-21
Bronchoalveolar Lavage • Cough and postbronchoscopic fever can follow BAL • Hypoksemia is less common due to standard use of oxygen inhalation during bronchoscopy Van Vyve T, Chanez P, Bousquet J, et al. Am Rev Respir Dis 1992; 46: 116-21
Bronchoalveolar Lavage • Studies of BAL in asthma have revealed increased numbersand activation of inflammatory cells and higher levels of mediatorswhen compared to subjects without asthma • Asthmasubjects show increased numbers of BAL eosinophils, evenwhen the disease is mild and stable Bousquet J, Chanez P, Lacoste JY, et al. N Engl J Med 1990; 3: 1033-9
Bronchoalveolar Lavage • Macrophage activation hasbeen described in symptomatic asthma and with nocturnal exacerbations Wenzel SE, Trudeau JB, Westcott JY, et al. J Allergy Clin Immunol 1994; 94: 870-81 • While BAL neutrophilia is not a predominantfeature of mild to moderate asthma, it has been describedin response to occupational challenge with isocyanateor grain dust and endotoxin-contaminated allergen extracts Hunt LW, Gleich GJ, Ohnishi T, et al. Am J Respir Crit Care Med 1994; 149: 1471-5 Deetz DC, Jagielo PJ, Quinn TJ, et al. Am J Respir Crit Care Med 1997; 155: 254-9
Bronchoalveolar Lavage • Subgroups of the cells that are obtained with BAL can be evaluated • In the BAL fluid of asthmatic patients eosinophil count and CD5+ T-lymphocytes with CD25 were significantly increased, while CD3, CD4, CD8, CD16/CD56 and CD19 percentages were not significantly different from that of control subjects Harmancı E, Gülbaş Z, Özdemir N, et al. Tuberk Toraks 2001; 49: 187-92
Bronchoalveolar Lavage • Many mediators and cytokines have been detectedin BAL fluid of asthma patients, including: IL-1 IL-6 IL-2 IL-10 IL-4 GM-CSF IL-5 TNF-α Zangrilli JG, Peters SP. Cytokines in allergic airway disease.In BusseWW, HolgateST, eds. Asthma and Rhinitis.Blackwell Scientific Publications, Cambridge. 1995, 426–436.
Bronchoalveolar Lavage • Other studies have noted increased levels of mRNA forseveral cytokines in BAL cells, including: TNF-α IL-4 GM-CSF IL-5 IL-1 IL-6 IL-2 IL-13 IL-3 Zangrilli JG, Peters SP. Cytokines in allergic airway disease.In BusseWW, HolgateST, eds. Asthma and Rhinitis.Blackwell Scientific Publications, Cambridge. 1995, 426–436.
Bronchoalveolar Lavage • Other mediators detected in BAL fluid include: • Leukotrienes • Prostaglandins • Histamine • Tryptase • Soluble adhesion molecules
Bronchoalveolar Lavage • Bronchoalveolar lavage has also been performed toevaluate the effects of asthma therapies (corticosteroids, theophylline,beta-agonists, cromolyn sodium, nedocromil sodium,cetirizine, leukotriene inhibitors, etc.) on parameters of airwayinflammation
Bronchial Biopsy • The use of bronchial biopsy for research purposes in asthmawas first reported in 1977 Molina C,Brun J, Coulet M, et al.Immunopathologyof the bronchial mucosa in late onset asthma. Clin Allergy1977; 7:137–45 • Bronchialbiopsy provides valuable insight into the morphology ofthe asthmatic airways, enabling detailed study of the epithelium,basement membrane, and submucosa Djukanovic R. Bronchial biopsies. In HolgateST, BusseW,eds. Asthma and Rhinitis. Blackwell Scientific Publications, Boston.1994, 118–129.
Bronchial Biopsy • Immunohistochemical studies of bronchial biopsieshave enabled quantification of the inflammatory cells, suchas mast cells, eosinophils, and T lymphocytes, and the extentof activation of these cells Djukanovic R, WilsonJW, BrittenKM, et al. Am Rev Respir Dis1990; 142:863–71 Azzawi M, Bradley B, Jeffery PK, et al. Am Rev Respir Dis 1990; 142:1407–13
Bronchial Biopsy • Using transmission electron microscopy, it has been possibleto study the ultrastructure of inflammatory cells Azzawi M, Bradley B, Jeffery PK, et al. Am Rev Respir Dis 1990; 142:1407–13 • The immunogold technique has localized cytokines to ultrastructuralelements of cells and adhesion molecules within theepithelium Lackie P, BakerJE, GunthertU, et al. Am J Respir Cell Mol Biol 1997; 16:14–22
Bronchial Biopsy • Kraft and colleaguesreportedthe first study in which transbronchial biopsies were obtainedin asthma subjects. Prominent tissue eosinophilia was seen at4:00 A.M. in asthma subjects with nocturnal decline in pulmonaryfunctions compared to asthmatic subjects without nocturnalasthma. Kraft M, Djukanovic R, Wilson S, et al. Am J Respir Crit CareMed 1996; 154:1505–10
Bronchial Brushing • The techniques of BAL and bronchialbrushing not only provide complementary histologic informationbut also cells for in vitro study • The majority of cells obtainedby brushing are bronchial epithelial cells • Bronchial epithelial cells release inflammatory mediatorsand participate in airway immune responses as antigen–presenting cells
Bronchial Brushing • Bronchial epithelial cells from asthmatic subjectshave also been shown to have enhanced expression ofHLA-DR and ICAM-1 compared withnormal subjects Vignola AM, Campbell AM, Chanez P, et al. Am Rev RespirDis1993; 148:689–94 • They can also release mediators relevantto the pathogenesis of asthma, such as 15-hydroxy-eicosatetranoicacid (15 HETE), prostaglandin E2, and fibronectin Campbell AM, Chanez P, Vignola AM, et al. Am Rev RespirDis1993; 147:529–34
Bronchial Brushing • Epithelial cells from asthmatic subjects have also enhancedexpression of GM-CSF, which decreases following treatmentwith inhaled steroids Sousa AR, Poston RN, Lane SJ, et al. Am Rev Respir Dis 1993; 147:1557–61
Segmental Allergen Challenge • The majority of patients with asthma have allergicsensitivities that can be used to provoke airway inflammation • Aerosolized allergen challenge results in the development ofbronchial obstruction, airway hyperresponsiveness, eosinophilicinfiltration and activation, increased superoxide production,and other indices of inflammation de Monchy JGR, Kauffman HF, Venge P, et al. Am Rev RespirDis1985; 131:373–6 Diaz P, Gonzalez MC, Galleguillos FR, et al. Am Rev RespirDis1989; 139:1383–9 Calhoun WJ, Bush RK.J Allergy Clin Immunol 1990; 86:306–13
Segmental Allergen Challenge • Only a small and variable fraction of the dose delivered by thenebulizer actually reaches the lower airway • Moreover, the siteof deposition is unknown unless radiotracers are used, and inany case is uncontrolled • Finally, the quantity of allergen thatcan be delivered is limited by safety considerations due to airwayobstruction
Segmental Allergen Challenge • Using segmental allergen challenge allergen dosing and localization are moreprecise, because allergen is delivered to a specific airway segmentunder direct visualization • Multiple segments can safelybe challenged with different antigen doses (for dose–responsestudies) • The same dose can be used in multiple segments(for kinetic or interventional studies) Calhoun WJ, Jarjour NN, Gleich GJ, et al. J Allergy ClinImmunol1996; 98:S46–S50. Kane GC, Pollice M, Kim CJ, et al. J AllergyClinImmunol1996; 97:646–54. Shaver JR, Zangrilli JG, Cho SK, et al. Am JRespirCrit Care Med 1997; 155:442–8.
Segmental Allergen Challenge • The degree ofgeneralized bronchial obstruction is less than that seen withaerosol challenge, and the degree of inflammation is greater Calhoun WJ, Jarjour NN, Gleich GJ, et al. Am RevRespir Dis 1993; 147:1465–71 • Instrumentation and BAL per se do not evoke generalizedpulmonary inflammation Calhoun WJ, Reed HE, Moest D, et al. AmRev Respir Dis 1992; 145:317–25 Jarjour NN, Calhoun WJ.Am Rev RespirDis 1990; 142:100–3
Segmental Allergen Challenge • SAC localizes allergenchallenge to the small airways, which are sites of inflammation and bronchial obstruction in asthma Saetta M, DiStefano A, Rosina C, et al. Am Rev Respir Dis 1991; 143:138–43 Kraft M, DjukanovicR, Wilson S, et al. Am J Respir Crit CareMed 1996; 154:1505–10 Wagner EM, Liu MC, Weinmann GG, et al. Am Rev Respir Dis 1990; 141:584–8
Segmental Allergen Challenge • While SAC is a powerful tool for studying allergen-driven airwayinflammation, care should be taken when extrapolatingSAC findings to natural exacerbations of asthma
Segmental Allergen Challenge • Wenzel and colleagues showed that the concentration ofleukotriene C4 was significantly greater after endobronchialallergen challenge in asthmatics compared to nonasthmaticatopics Wenzel SE, Larsen GL, Johnston K, et al. Am Rev RespirDis1990; 142:112–9 • Preliminary data suggest that failure to secrete IL-10after allergen challenge might also differentiate allergic asthmafrom allergic rhinitis subjects Calhoun WJ, Hinton KL, Brick JJ, et al. Am J RespirCrit Care Med 1996; 153:A881
Segmental Allergen Challenge • Shaver and colleaguesreported that the increase in BAL eosinophils andIL-5 in response to antigen SAC were similar in allergic asthmaticand allergic nonasthmatic subjects • Interestingly, subjectswith documented late asthmatic response to whole lung challengeshowed the strongest cellular and cytokine responses toSAC Shaver JR, O’Connor JJ, Pollice M, et al. Am J Respir Crit Care Med 1993; 152:1189–97