Gennaro Mazzarella

New insight into adiponectin role in obesity and obesity-related diseases.

Obesity is a major health problem strongly increasing the risk for various severe related complications such as metabolic syndrome, cardiovascular diseases, respiratory disorders, diabetic retinopathy, and cancer. Adipose tissue is an endocrine organ that produces biologically active molecules defined “adipocytokines,” protein hormones with pleiotropic functions involved in the regulation of energy metabolism as well as in appetite, insulin sensitivity, inflammation, atherosclerosis, cell proliferation, and so forth. In obesity, fat accumulation causes dysregulation of adipokine production that strongly contributes to the onset of obesity-related diseases. Several advances have been made in the treatment and prevention of obesity but current medical therapies are often unsuccessful even in compliant patients. Among the adipokines, adiponectin shows protective activity in various processes such as energy metabolism, inflammation, and cell proliferation. In this review, we will focus on the current knowledge regarding the protective properties of adiponectin and its receptors, AdipoRs (“adiponectin system”), on metabolic complications in obesity and obesity-related diseases. Adiponectin, exhibiting antihyperglycemic, antiatherogenic, and anti-inflammatory properties, could have important clinical benefits in terms of development of therapies for the prevention and/or for the treatment of obesity and obesity-related diseases.

T lymphocyte phenotypic profile in lung segments affected by cavitary and non-cavitary tuberculosis

Clinical manifestations of pulmonary tuberculosis (TB) may depend on a complex interaction between the host and the pathogen. Clinical outcomes of pulmonary tuberculosis are variable, ranging from asymptomatic lifelong infection to parenchymal lung destruction, resulting in cavitary lesions. To investigate the hypothesis that local cellular immune response may affect presentation and outcome in tuberculosis, we performed bronchoalveolar lavage (BAL) in lung segments affected by cavitary and non‐cavitary tuberculosis. We then correlated the type of cellular response at the level of the involved lung segments with clinical evolution in terms of cavity formation. We found alveolar lymphocytosis in patients with both cavitary and non‐cavitary pulmonary tuberculosis, with increased CD4+ lymphocytes in patients with non‐cavitary pulmonary tuberculosis. A predominant Th1 immune response has been observed in non‐cavitary patients, while cavitary involved segments exhibit the presence of Th2 lymphocyte subsets. These data, while confirming the importance of Th1‐type CD4+ cells and IFN‐γ in effective cellular immunity in active pulmonary tuberculosis, also suggest that the presence of Th2 lymphocytes may contribute to tissue necrosis phenomena associated with cavitary evolution of pulmonary tuberculosis. Our observations indicate the importance of the type of local immune response at the site of disease in the development of different clinical characteristics and outcome in pulmonary tuberculosis.

Prognostic value of p53 in non-small cell lung cancer: Relationship with proliferating cell nuclear antigen and cigarette smoking

p53 mutations are among the most frequent genetic alterations reported in human lung cancer. Although the prognostic value of altered p53 expression is still debated, it is accepted widely that estimation of the proliferation rate has an important prognostic role. Moreover, an association between certain types of human lung cancers and tobacco use is well known. Drawing from this background, we investigated the immunohistochemical expression of mutant oncogenic p53 protein, and related it to the smoking history of 61 patients with non-small cell lung carcinoma (NSCLC) and to the expression pattern of proliferating cell nuclear antigen (PCNA), which is considered to be an important negative prognostic factor in several neoplasms. We found p53 overexpression in 22 (36.1%) specimens, including 16 squamous carcinomas (41%) and six (27.2%) adenocarcinomas. PCNA nuclear staining was detected in 98.4% of the specimens, and a significantly higher PCNA expression score was found in all of the p53-positive samples. When the patient survival time was compared, p53 accumulation had a statistically significant negative prognostic value (P < .001). This was supported by a Kaplan-Meier survival percentage plot of immunohistochemically p53-undetectable specimens and p53-detectable specimens. These latter patients had a greatly reduced survival time. A relationship was established between p53 immunohistochemical detection and the smoking history of the patients. None of the specimens from the nonsmoking patients expressed immunohistochemically detectable p53 protein. Altered p53 expression was detected in 40.7% of smoking patients. Our findings support the hypothesis of involvement of p53 mutations in tobacco-induced carcinogensis and indicate that altered p53 expression plays an important prognostic role in NSCLC in smokers.

Arachidonic acid metabolism in inflammatory cells of patients with bronchial asthma

Over the last few years, the demonstration of beneficial effects of leukotriene receptor antagonists in various forms of asthma has renewed clinical and pharmacologic interest in this class of lipid mediators. Several studies demonstrated an increased biosynthesis of cysteinyl leukotrienes (CysLT) in asthmatic patients. However, the reasons for the dysregulated production of CysLTs in asthmatic patients are not completely defined. An improved method of lipid mediator detection and the availability of cells isolated from human airways (by bronchoalveolar lavage [BAL] and bronchial biopsies) have allowed initial studies to address this issue. Eosinophils retrieved from inflamed airways of asthmatics have a larger arachidonic acid (AA) content than their blood counterpart. The high level of AA in these cells is primarily due to a remodeling of endogenous arachidonate pools with the accumulation of this fatty acid in a triglyceride‐associated pool. In addition, elevated levels of a secretory form of phospholipase A2, the key enzyme initiating the cascade of CysLTs, are found in the BAL of asthmatics. Finally, eosinophils isolated from the BAL of asthmatics have an increased expression of LTC4 synthase. The level of expression of this enzyme correlates with the increased amount of CysLTs produced in the airways of these patients. Taken together, these data identify at least two possible mechanisms to explain the excessive CysLT production in asthmatics:

Adiponectin affects lung epithelial A549 cell viability counteracting TNFa and IL-1ß toxicity through AdipoR1

Adiponectin (Acrp30) exerts protective functions on metabolic and cellular processes as energy metabolism, cell proliferation and differentiation by two widely expressed receptors, AdipoR1 and AdipoR2. To date, the biological role of Acrp30 in lung has not been completely assessed but altered levels of Acrp30 and modulated expression of both AdipoRs have been related to establishment and progression of chronic obstructive pulmonary disease (COPD) and lung cancer. Here, we investigated the effects of Acrp30 on A549, a human alveolar epithelial cell line, showing how, in a time and dose-dependent manner, it decreases cell viability and increases apoptosis through ERK1/2 and AKT. Furthermore, we examined the effects of Acrp30 on A549 cells exposed to TNFα and/or IL-1ß, two potent lung inflammatory cytokines. We showed that Acrp30, in dose- and time-dependent manner, reduces cytotoxic effects of TNFα and/or IL-1ß improving cell viability and decreasing apoptosis. In addition, Acrp30 inhibits NF-κB nuclear trans-activation and induces the expression of the anti-inflammatory IL-10 cytokine without modifying that of pro-inflammatory IL-6, IL-8, and MCP-1 molecules via ERK1/2 and AKT. Finally, specifically silencing AdipoR1 or AdipoR2, we observed that NF-κB inhibition is mainly mediated by AdipoR1. Taken together, our data provides novel evidence for a direct effect of Acrp30 on the proliferation and inflammation status of A549 cells strongly supporting the hypothesis for a protective role of Acrp30 in lung. Further studies are needed to fully elucidate the Acrp30 lung effects in vivo but our results confirm this adipokine as a promising therapeutic target in lung diseases.

Potential Mechanisms Linking Atherosclerosis and Increased Cardiovascular Risk in COPD: Focus On Sirtuins

The development of atherosclerosis is a multi-step process, at least in part controlled by the vascular endothelium function. Observations in humans and experimental models of atherosclerosis have identified monocyte recruitment as an early event in atherogenesis. Chronic inflammation is associated with ageing and its related diseases (e.g., atherosclerosis and chronic obstructive pulmonary disease). Recently it has been discovered that Sirtuins (NAD+-dependent deacetylases) represent a pivotal regulator of longevity and health. They appear to have a prominent role in vascular biology and regulate aspects of age-dependent atherosclerosis. Many studies demonstrate that SIRT1 exhibits anti-inflammatory properties in vitro (e.g., fatty acid-induced inflammation), in vivo (e.g., atherosclerosis, sustainment of normal immune function in knock-out mice) and in clinical studies (e.g., patients with chronic obstructive pulmonary disease). Because of a significant reduction of SIRT1 in rodent lungs exposed to cigarette smoke and in lungs of patients with chronic obstructive pulmonary disease (COPD), activation of SIRT1 may be a potential target for chronic obstructive pulmonary disease therapy. We review the inflammatory mechanisms involved in COPD-CVD coexistence and the potential role of SIRT1 in the regulation of these systems.

Adiponectin: an attractive marker for metabolic disorders in Chronic Obstructive Pulmonary Disease (COPD).

Chronic Obstructive Pulmonary Disease (COPD) is a chronic inflammatory lung disease which may be complicated by development of co-morbidities including metabolic disorders. Metabolic disorders commonly associated with this disease contribute to lung function impairment and mortality. Systemic inflammation appears to be a major factor linking COPD to metabolic alterations. Adipose tissue seems to interfere with systemic inflammation in COPD patients by producing a large number of proteins, known as “adipokines”, involved in various processes such as metabolism, immunity and inflammation. There is evidence that adiponectin is an important modulator of inflammatory processes implicated in airway pathophysiology. Increased serum levels of adiponectin and expression of its receptors on lung tissues of COPD patients have recently highlighted the importance of the adiponectin pathway in this disease. Further, in vitro studies have demonstrated an anti-inflammatory activity for this adipokine at the level of lung epithelium. This review focuses on mechanisms by which adiponectin is implicated in linking COPD with metabolic disorders.

Phenotypic features of alveolar monocytes/macrophages and IL‐8 gene activation by IL‐1 and TNF‐α in asthmatic patients

The alveolar macrophage (AM), a major defense cell in the lung, participates in immune and inflammatory reactions through the release of several regulatory and chemotactic cytokines. In particular, macrophages are considered to play a pivotal proinflammatory role in the production and maintenance of airway inflammation and bronchial hyperreactivity. To assess the phenotypic pattern of AM from asthmatic subjects, we performed the following experiments:

Morphology changes in human lung epithelial cells after exposure to diesel exhaust micron sub particles (PM1.0) and pollen allergens

In the recent literature there has been an increased interest in the effects of particulate matter on the respiratory tract. The objective of this study was to use an in vitro model of type II lung epithelium (A549) to evaluate the cell ability to take up sub-micron PM(1.0) particles (PM(1.0)), Parietaria officinalis (ALL), and PM(1.0) + ALL together. Morphological analysis performed by Transmission Electron Microscope (TEM) showed that PM and ALL interacted with the cell surface, then penetrating into the cytoplasm. Each single treatment was able to point out a specific change in the morphology. The cells treated appear healthy and not apoptotic. The main effect was the increase of: multilamellar bodies, lysosomal enzymes, microvilli, and presence of vesicle/vacuoles containing particles. These observations demonstrate morphological and functional alterations related to the PM(1.0) and P. officinalis and confirm the induction of the inflammatory response in lung cells exposed to the inhalable particles.

Adiponectin in Asthma: Implications for Phenotyping

Asthma is a heterogeneous inflammatory airway disease, which exhibits multiple phenotypes, mainly defined by a combination of different clinical features. Asthma phenotypes include age at onset, smoking status, exacerbations frequency, and co-existence of obesity. Links between specific biological pathways and phenotypes are emerging. The genetic background together with detectable biomarkers could more accurately identify asthma phenotypes consistent with clinical-physiological characteristics and response to therapies. Several cross-sectional studies indicate a strict correlation between adipose tissue, obesity, and asthma suggesting that obesity is not only a risk factor for asthma but also a predictor of poor prognosis. Despite the strong clinical correlation between obesity and asthma, the underlying biological pathways have not been extensively investigated. Recently, a pivotal role for adiponectin has been recognized in physio-pathological conditions of lung. Adiponectin is expressed as a 247 residues long protein and secreted as oligomers of low, medium and high molecular weight. The larger oligomers seem to have a more pronounced insulinsensitizing, anti-atherogenic, and anti-inflammatory effects. Interestingly, the three receptors AdipoR1, AdipoR2, and Tcadherin mediating adiponectin activity are expressed on lung cells mediating adiponectin beneficial effects. Recently, different studies demonstrated the involvement of adiponectin in asthma since its levels and the expression of AdipoR1, AdipoR2 and T-cadherin are modulated in asthma patients and in asthma mouse models. In the present study, we review the literature reporting adiponectin impact on expression of specific clinical asthma phenotypes.