Introduction: Bronchiectasis is a common chronic debilitating respiratory condition. Patients suffer daily cough, excess sputum production and recurrent chest infections because of inflamed and permanently damaged airways. The pathogenesis of bronchiectasis is poorly understood. Pulmonary pathology shows excess neutrophilic airways inflammation, but despite this over two thirds of patients are chronically infected with potential pathogenic microorganisms. The acute inflammatory response is a protective mechanism that is evolved to eliminate invading organisms and should ideally be self-limiting and lead to complete resolution. The driver for persistent neutrophilic airway inflammation in bronchiectasis is unknown, but infection is considered to play a major role. AIMS The main aims of this thesis were to: (i) Characterize neutrophils in the serum and airways in bronchiectasis in the stable state and during exacerbations; (ii) Cohort study to establish if LXA4 deficiency correlates with disease severity (iii) Characterize lipids in bronchiectasis airways and peripheral blood to establish the correlation of LXA4 to disease severity; (iv) To investigate a potential mechanism for low levels of LXA4 in bronchiectasis, lipoxin biosynthetic genes expression will be measured; (v) Assess the anti-inflammatory and pro resolution effect of LXA4 on neutrophils and monocyte derived macrophages from healthy volunteers; (vi) Assess the anti-inflammatory and pro resolution effect of LXA4 on neutrophils during exacerbations in bronchiectasis and community acquired pneumonia. Methods (I) To establish the serum neutrophil subtype in stable state and following antibiotic treatment in patients with bronchiectasis, the following studies were done. Inclusion criteria: Patients aged 18-80 were recruited. All had an established radiological diagnosis of bronchiectasis (CT of the chest). Patients had clinically significant bronchiectasis, aetiology being either idiopathic or post infection. Exclusion Criteria: current smokers or ex-smokers of less than 1 year; >20 pack year history; cystic fibrosis; active allergic bronchopulmonary aspergillosis; active tuberculosis; poorly controlled asthma; severe COPD requiring nebulised bronchodilators or long term oxygen therapy; patients on aspirin or leukotriene inhibitors, pregnancy or breast feeding, active malignancy. A. 6 patients with mild bronchiectasis, 6 patients with severe bronchiectasis and 6 healthy volunteers were recruited. Serum and airways neutrophils were subsequently isolated. Neutrophil apoptosis, CD11b and CD62L expression, myeloperoxidase release, superoxide generation, phagocytosis and killing of GFP labeled bacteria were assessed. B. To compare serum with airways neutrophils function, bacterial phagocytosis and killing of GFP labeled bacteria was done, with both serum and airways neutrophils. Samples were obtained from the above group of patients. C. To establish neutrophil function following antibiotic treatment, 6 bronchiectasis patients at the beginning (day1) and the end (day14) of intravenous antibiotic therapy for an exacerbation were studied. As a control group, 6 community acquired pneumonia patients at the beginning (day1) and the end (day 5) of intravenous antibiotic therapy for infection were studied. Induced sputum and peripheral blood was taken at day1 and 5, where able. Phagocytosis and killing of GFP labeled bacteria was assessed and the two groups compared. (II) To address if lipoxin A4 deficiency correlates with disease severity, a cohort study was done in bronchiectasis patients. 169 patients were recruited and followed up for 1 year. Assessments done were Bronchiectasis severity index, systemic inflammatory markers (white cell count, ESR and c-reactive protein), Forced Expired Volume in 1sec, Forced Vital Capacity and its ratio, antibiotic courses in 1 year, hospital admissions in 1 year, sputum microbiology, quality of life assessments by Leicester Cough Questionnaire and St. Georges Respiratory Questionnaire, interleukin 8, myeloperoxidase, neutrophil elastase and leukotriene B4 (from sputum). (III) To assess effect of lipoxin on disease severity, 6 healthy volunteers, 10 patients with mild disease, 15 with moderate and 9 with severe disease were recruited. Disease severity was calculated as per the bronchiectasis severity index. All participants had 60mls of blood taken and underwent a bronchoscopy. Two segments of the lungs were washed out from bronchiectasis patients, an area affected by bronchiectasis and an area unaffected by bronchiectasis. This led to patients acting as their own internal control. Serum and airways neutrophils (from both segments) were subsequently isolated. Assessments done were systemic inflammatory markers (white cell count, ESR and c-reactive protein), serum lipoxin A4 and the cathelicidin LL-37, Forced Expired Volume in 1sec, Forced Vital Capacity and its ratio, transfer factor for carbon monoxide, antibiotic courses in 1 year, hospital admissions in 1 year and sputum microbiology. Phagocytosis and bacterial killing were assessed by both serum and airways neutrophils. From bronchoalveolar lavage fluid (BALF), I measured myeloperoxidase and neutrophil elastase. For both serum and BALF, lipidomics were obtained. (IV) To address the impact of anatomic compartment, gene expression was measured in from endobronchial brushings from the same cohort of bronchiectasis patients and controls as above, where samples were available. qPCR was performed for the following eicosanoid biosynthetic genes- 5 Lipoxygenase (LOX), 15 LO-A, 15LO-B and leukotriene (LT) A4 hydrolase. (V) To assess the anti inflammatory and pro resolution effect of LXA4 on neutrophils and monocyte derived macrophages from healthy volunteers, freshly isolated PMN will be treated with LXA4 or vehicle control. Spontaneous apoptosis was measured. fMLF and cytochalasin B was added and the inflammatory response assessed measuring myeloperoxidase (MPO), free neutrophil elastase (NE), CD11b, CD18 and CD62L. Human monocytes and PMNs were isolated from bronchiectasis patients. Following differentiation, LXA4 treated or control adherent, washed MDMs will be incubated with apoptotic stained PMNs. Efferocytosis was analyzed by flow cytometry. (VI) To establish the effect of Lipoxin A4 on neutrophil function following antibiotic treatment, the same study group used to evaluate aim 1 was taken. As a control group, 6 community acquired pneumonia patients at the beginning (day1) and the end (day 5) of oral or intravenous antibiotic therapy for infection were studied. Induced sputum and peripheral blood was taken at day1 and 5, where able. Phagocytosis and killing of GFP labeled bacteria and the effect of Lipoxin A4 was assessed and the two groups compared. Serum and sputum lipidomics were obtained in bronchiectasis exacerbations on day 1 and day 14. Serum lipidomics was obtained in pneumonia on day 1 and day 5. RESULTS (I) Neutrophil sub type study (Studied on healthy volunteers/ mild/ severe bronchiectasis) Peripheral blood neutrophils from bronchiectasis patients showed that there was significantly more viable neutrophils in mild and severe bronchiectasis compared to healthy volunteers, p=0.002 and p=0.005 respectively. In addition, there was significantly less apoptotic neutrophils in mild and severe bronchiectasis compared to healthy volunteers, p=0.0003 and p < 0.0001 respectively. There was a significantly higher level of CD11b in the mild (p=0.01) and severe bronchiectasis (p=0.01) compared to healthy volunteers. There was more CD62L shedding (p=0.02) and myeloperoxidase release (p=0.04) in bronchiectasis compared to healthy volunteers. There was lesser phagocytosis in mild (p=0.04) and severe (p=0.03) bronchiectasis compared to healthy volunteers. This led to lesser bacterial killing in mild (p=0.04) and severe (p=0.0004) bronchiectasis compared to healthy volunteers.

Lipoxina A4 (LXA4) é um eicosanoide derivado do metabolismo do ácido araquidônico pelas lipoxigenases (5, 12 e 15-LO), tendo propriedades antiinflamatórias e pró-resolução. A estratégia de uso de LXA4 encapsulada em micropartículas de PLGA como fármaco tem fundamento nas propriedades que tais polímeros têm de preservar as atividades biológicas de moléculas diversas, como dos lipídeos, e promover liberação prolongada e sustentada das mesmas. No presente estudo, tivemos como hipótese de trabalho que a encapsulação de LXA4 em micropartículas de PLGA (LXA4-MS) preserva suas atividades biológicas, e mais eficientemente, acelera o fechamento de úlceras induzidas na pele de ratos. Para tanto, um modelo de úlceras cutâneas na região dorsal de ratos foi utilizado. As LXA4-MS foram fixadas em pele com adesivo biológico de fibrina, e seus efeitos comparados com aqueles induzidos por micropartículas vazias (Un-MS), LXA4 solúvel ou veículo (PBS). Nossos resultados mostraram que LXA4-MS aceleram a cicatrização da ferida, pois no 7º dia após a lesão, reduziu em 80% o diâmetro da úlcera inicial, enquanto no mesmo período, nas úlceras tratadas com LXA4 solúvel, Un-MS ou veículo ocorreu diminuição de somente 60%, 45% e 39%, respectivamente. O aumento do índice de cicatrização induzido pelo tratamento das úlceras com LXA4-MS foi acompanhado pela diminuição das citocinas pró-inflamatórias IL- 1?, TNF-?, e aumento de TGF- ?, uma citocina antiinflamatória indutora da deposição de colágeno. Além disso, nas úlceras tratadas com LXA4-MS o infiltrado inflamatório foi reduzido no tecido de cicatrização, como demonstrado pela diminuição de infiltrado celular, de MPO e de mRNA da metaloproteinase MMP8. Por outro lado, LXA4-MS induziu aumento da deposição de colágeno e do número de vasos sanguíneos, de NAG e de IL-4, quando comparado com os demais tratamentos. Quando as úlceras foram tratadas concomitantemente com LXA4-MS e o antagonista do receptor de LXA4 (ciclosporina H), observamos reversão de cerca de 50% no índice de cicatrização promovido pelo mediador encapsulado, sugerindo que os efeitos tópicos do tratamento com LXA4 são devidos à sua interação com seu receptor específico. Nossos resultados sugerem que novas formulações farmacêuticas para tratamento de úlceras cutâneas poderão ser obtidas com LXA4-MS. / Lipoxin A4 (LXA4) is an eicosanoid derived from the metabolism of arachidonic acid by lipoxygenases (5, 12, and 15-LO), having anti-inflammatory and pro-resolution properties. The strategy of using LXA4 encapsulated in PLGA microparticles as drug is due to some properties that such polymers have to preserve the biological activity of several molecules such as lipids, and promote a prolonged and sustained release of these molecules. In the present study, we hypothesized that the encapsulation of LXA4 in PLGA microparticles (LXA4-MS) preserves its biological activities, and more efficiently accelerates the closing of ulcers induced in the skin of rats. Thus, a model for cutaneous ulcers in the dorsal region of rats was used. The LXA4-MS were fixed in skin using biological adhesive of fibrin, and their effects compared to those induced by empty microparticles (Un-MS), soluble LXA4 or vehicleOur results showed that LXA4-MS accelerate wound healing, once on day 7 after injury, reduced by 80% the diameter of the initial ulcer, while at the same time, the ulcers treated with soluble LXA4, Un-MS or vehicle was decreased of only 60%, 45% and 39%, respectively. The increased healing rate of ulcers induced by treatment with LXA4-MS was accompanied by the decrease of pro-inflammatory cytokines IL-1?, TNF-?, and a TGF-? increasing, an anti-inflammatory cytokine-inducing collagen deposition. In addition, the inflammatory infiltrate was reduced in scar tissue as demonstrated by the decrease of neutrophils, MPO and MMP8 metalloproteinase mRNA. Moreover, LXA4-MS induced increase in collagen deposition and the number of blood vessels when compared with the other controls. When the ulcers were treated concomitantly with LXA4-MS and the antagonist LXA4 receptor (ALX), cyclosporine H, we observed the reversal of about 50% in healing rates promoted by the encapsulated agent, suggesting that topical treatment effects of LXA4 are due to interaction with its own receptor. Our results suggest that new pharmaceutical formulations for the treatment of skin ulcers can be obtained with LXA4-MS.

Lipoxina A4 (LXA4) é um eicosanoide derivado do metabolismo do ácido araquidônico pelas lipoxigenases (5, 12 e 15-LO), tendo propriedades antiinflamatórias e pró-resolução. A estratégia de uso de LXA4 encapsulada em micropartículas de PLGA como fármaco tem fundamento nas propriedades que tais polímeros têm de preservar as atividades biológicas de moléculas diversas, como dos lipídeos, e promover liberação prolongada e sustentada das mesmas. No presente estudo, tivemos como hipótese de trabalho que a encapsulação de LXA4 em micropartículas de PLGA (LXA4-MS) preserva suas atividades biológicas, e mais eficientemente, acelera o fechamento de úlceras induzidas na pele de ratos. Para tanto, um modelo de úlceras cutâneas na região dorsal de ratos foi utilizado. As LXA4-MS foram fixadas em pele com adesivo biológico de fibrina, e seus efeitos comparados com aqueles induzidos por micropartículas vazias (Un-MS), LXA4 solúvel ou veículo (PBS). Nossos resultados mostraram que LXA4-MS aceleram a cicatrização da ferida, pois no 7º dia após a lesão, reduziu em 80% o diâmetro da úlcera inicial, enquanto no mesmo período, nas úlceras tratadas com LXA4 solúvel, Un-MS ou veículo ocorreu diminuição de somente 60%, 45% e 39%, respectivamente. O aumento do índice de cicatrização induzido pelo tratamento das úlceras com LXA4-MS foi acompanhado pela diminuição das citocinas pró-inflamatórias IL- 1?, TNF-?, e aumento de TGF- ?, uma citocina antiinflamatória indutora da deposição de colágeno. Além disso, nas úlceras tratadas com LXA4-MS o infiltrado inflamatório foi reduzido no tecido de cicatrização, como demonstrado pela diminuição de infiltrado celular, de MPO e de mRNA da metaloproteinase MMP8. Por outro lado, LXA4-MS induziu aumento da deposição de colágeno e do número de vasos sanguíneos, de NAG e de IL-4, quando comparado com os demais tratamentos. Quando as úlceras foram tratadas concomitantemente com LXA4-MS e o antagonista do receptor de LXA4 (ciclosporina H), observamos reversão de cerca de 50% no índice de cicatrização promovido pelo mediador encapsulado, sugerindo que os efeitos tópicos do tratamento com LXA4 são devidos à sua interação com seu receptor específico. Nossos resultados sugerem que novas formulações farmacêuticas para tratamento de úlceras cutâneas poderão ser obtidas com LXA4-MS. / Lipoxin A4 (LXA4) is an eicosanoid derived from the metabolism of arachidonic acid by lipoxygenases (5, 12, and 15-LO), having anti-inflammatory and pro-resolution properties. The strategy of using LXA4 encapsulated in PLGA microparticles as drug is due to some properties that such polymers have to preserve the biological activity of several molecules such as lipids, and promote a prolonged and sustained release of these molecules. In the present study, we hypothesized that the encapsulation of LXA4 in PLGA microparticles (LXA4-MS) preserves its biological activities, and more efficiently accelerates the closing of ulcers induced in the skin of rats. Thus, a model for cutaneous ulcers in the dorsal region of rats was used. The LXA4-MS were fixed in skin using biological adhesive of fibrin, and their effects compared to those induced by empty microparticles (Un-MS), soluble LXA4 or vehicleOur results showed that LXA4-MS accelerate wound healing, once on day 7 after injury, reduced by 80% the diameter of the initial ulcer, while at the same time, the ulcers treated with soluble LXA4, Un-MS or vehicle was decreased of only 60%, 45% and 39%, respectively. The increased healing rate of ulcers induced by treatment with LXA4-MS was accompanied by the decrease of pro-inflammatory cytokines IL-1?, TNF-?, and a TGF-? increasing, an anti-inflammatory cytokine-inducing collagen deposition. In addition, the inflammatory infiltrate was reduced in scar tissue as demonstrated by the decrease of neutrophils, MPO and MMP8 metalloproteinase mRNA. Moreover, LXA4-MS induced increase in collagen deposition and the number of blood vessels when compared with the other controls. When the ulcers were treated concomitantly with LXA4-MS and the antagonist LXA4 receptor (ALX), cyclosporine H, we observed the reversal of about 50% in healing rates promoted by the encapsulated agent, suggesting that topical treatment effects of LXA4 are due to interaction with its own receptor. Our results suggest that new pharmaceutical formulations for the treatment of skin ulcers can be obtained with LXA4-MS.