Giuseppe Miserocchi

The effect of nanoparticle uptake on cellular behavior: disrupting or enabling functions?

Nanoparticles (NPs) are materials with overall dimensions in the nanoscale range. They have unique physicochemical properties, and have emerged as important players in current research in modern medicine. In the last few decades, several types of NPs and microparticles have been synthesized and proposed for use as contrast agents for diagnostics and imaging and for drug delivery; for example, in cancer therapy. Yet specific targeting that will improve their delivery still represents an unsolved challenge. The mechanism by which NPs enter the cell has important implications not only for their fate but also for their impact on biological systems. Several papers in the literature discuss the potential risks related to NP exposure, and more recently the concept that even sublethal doses of NPs may elicit a cell response has been proposed. In this review, we intend to present an overall view of cell mechanisms that may be perturbed by cell-NP interaction. Published data, in fact, emphasize that NPs should no longer be viewed only as simple carriers for biomedical applications, but that they can also play an active role in mediating biological effects.

Responses of pulmonary stretch receptors to static pressure inflations

Abstract The response of pulmonary stretch receptors to different values of transpulmonary pressure was studied in relation to their localisation in order to relate their activity to the mechanical properties of the structures containing them. Two types of receptors were found. In the type I receptors the frequency of discharge increased with increasing transmural pressure up to about 10 cm H 2 O and then remained constant, whereas in the type II receptors the frequency of discharge did not reach a plateau with a pressure of up to 30 cm H 2 O. From the trachea to the smaller airways type I receptors are progressively substituted by Type II receptors. Extrapulmonary stretch receptors of both types represent 94% of those having a tonic activity at zero transpulmonary pressure; 86% of all the receptors are recruited within a transpulmonary pressure of 8 cm H 2 O. We suggest that type I are tension receptors placed in parallel with the structures supporting the transmural pressure, whereas type II receptors are in series with these structures.

The sensitivity of versican from rabbit lung to gelatinase A (MMP‐2) and B (MMP‐9) and its involvement in the development of hydraulic lung edema

Large chondroitinsulphate‐containing proteoglycan (versican) isolated from rabbit lung was cleaved by purified gelatinase A (MMP‐2) and gelatinase B (MMP‐9), as well as by crude enzyme extract from rabbit lung with hydraulic edema. Gelatine zymography, performed after purification of gelatinases by affinity chromatography, demonstrated that the enzyme extract contained two main gelatinolytic bands at about 92 kDa and 72 kDa, identified by specific antisera as the latent proMMP‐9 and proMMP‐2, respectively. Moreover, enzyme extract from edematous lung showed an increased amount of the proteolytically activated forms of both gelatinases with respect to normal controls. These results suggest that MMP‐2 and MMP‐9 are involved in the breakdown of versican occurring in rabbit lung during the development of hydraulic edema.

Consensus definitions to promote an evidence-based approach to management of the pleural space. A collaborative proposal by ESTS, AATS, STS, and GTSC

The present project involved a collective effort agreed by the European Society of Thoracic Surgeons, the American Association for Thoracic Surgery, the Society of Thoracic Surgeons, and the General Thoracic Surgery Club to assemble a joint panel of experts to review the available data and address ambiguous aspects of chest tube definitions and nomenclature. The task force was composed of 11 invited participants, identified for their expertise in the area of chest tube management. The subject was divided in different topics, which were in turn assigned to at least two experts. The draft reports written by the experts on each topic were distributed to the entire expert panel, and comments solicited in advance of the meetings. During the meetings, the drafts were reviewed, discussed, and agreed on by the entire panel. Standardized definitions and nomenclature were proposed for the following topics related to chest tube management: pleural and respiratory mechanics after pulmonary resection; external suction versus no external suction; fixed versus variable suction; objective air leak evaluation; objective fluid drainage evaluation; and chest drain: type, number, and size. A standardized set of definitions and nomenclature were proposed to set a scientifically based framework with which to evaluate existing studies and to more clearly formulate questions, parameters, and outcomes for future studies.

Involvement of lung interstitial proteoglycans in development of hydraulic- and elastase-induced edema

We extracted and isolated proteoglycans from lung tissue samples obtained from three groups of anesthetized rabbits: 1) control animals (C; n= 8) killed by overdose after 180 min; 2) animals receiving an intravenous saline infusion (S; n = 4, 1.5 ml ⋅ kg-1 ⋅ min-1) for 180 min; 3) animals receiving an intravenous bolus of 200 μg of pancreatic elastase (E; n = 4), killed after 200 min. The lung dry weight-to-wet weight ratio in the three groups was 5.2 ± 0.2, 6.0 ± 0.4, and 5.6 ± 0.5, respectively. Gel-filtration analysis showed a massive fragmentation of the versican family of the extracellular matrix (ECM) in the S groups and a marked degradation of heparan sulfate-containing proteoglycans, including perlecan of the basement membrane, in the E group. The binding properties of total proteoglycans to other ECM components were lowered in both groups relative to control. The decrease in proteoglycan binding was more pronounced for collagen type IV in the E group relative to C (-93.5%, P < 0.05) and for hyaluronic acid in the S groups (-85.8%, P < 0.05). These findings suggest that elastase treatment produces a major degree of damage to the organization of basement membrane, whereas saline loading affects more markedly the architecture of interstitial ECM. Qualitative zymography performed on lung extracts showed increased gelatinase activities in both S and E groups, providing direct evidence that the activation of tissue proteinases may play a role in acute lung injury.

Proteoglycan involvement during development of lesional pulmonary edema

We evaluated the effect of pancreatic elastase (7 IU i.v.) on pulmonary interstitial pressure (Pip) in in situ rabbit lungs by a micropuncture technique through the intact parietal pleura. Pip was -10.8 +/- 2.2 (SD) cmH2O in the control condition, increased to +5.1 +/- 1.7 cmH2O at approximately 60 min [condition referred to as mild edema (ME)], and subsequently decreased to -0.15 +/- 0.8 cmH2O, remaining steady from 80 up to 200 min with a marked increase in lung wet-to-dry weight ratio [condition referred to as severe edema (SE)], suggesting an increase in tissue compliance. We functionally correlated the measured Pip to structural modifications of proteoglycans, the major interfibrillar component of the extracellular matrix (ECM). The strength of the noncovalent bonds linking proteoglycans to other ECM components decreased with increasing severity of edema, as indicated by the increased extractability of proteoglycans with guanidine hydrochloride. Total proteoglycan recovery (expressed as microgram hexuronate/g dry tissue) increased from 436.8 +/- 14 in the control condition to 495.3 +/- 23 and 547.0 +/- 10 in ME and SE, respectively. Gel-filtration chromatography showed in ME a fragmentation of heparan sulfate proteoglycans, suggesting that elastase treatment first affected basement membrane integrity, whereas large chondroitin sulfate proteoglycans were degraded only in SE. Elastase caused a fragmentation only of the core protein of proteoglycans, the binding properties of which to collagens, fibronectin, and hyaluronic acid were markedly decreased, as indicated by a solid-phase binding assay. The sequential degradation of heparan sulfate and chondroitin sulfate proteoglycans may account for the initial increase in microvascular permeability, followed by a loss of the native architecture of the ECM, which may be responsible for the increase in tissue compliance.

Lung toxicity induced by intratracheal instillation of size-fractionated tire particles

Tire particles (TP) represent a significant component of urban air pollution (PM), constituting more than 10% of PM10 mass at urban locations with heavy traffic. The purpose of this study was to evaluate the effects of size-fractionated TP in an animal exposure model frequently used to assess the health effects of air pollutants. Potential pro-inflammatory and toxic effects of TP2.5 (<2.5 microm) and TP10 (<10 microm) were investigated through instillation of suspensions of these materials in BALB/c mice. Bronchoalveolar lavage fluid (BALF) was screened for total protein, lactate dehydrogenase (LDH), alkaline phosphatase (AP), and beta-glucuronidase (B-Gluc) as markers of cytotoxicity; glutathione (GSH) and superoxide dismutase (SOD) as markers of oxidative potential; and tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-2 (MIP-2), and inflammatory cells as markers of inflammation. Concomitantly, histological analysis of TP-exposed lungs was performed. A single intratracheal instillation of 10 microg/100 microl, 100 microg/100 microl or 200 microg/100 microl was performed, and after 24h mice were euthanized and BALF examined. Inflammatory cellular profiles showed dose-dependent responses after TP10 exposure, while strong cytotoxic effects, including increases in total protein, LDH and AP, were observed to be associated to TP2.5 exposure. Histologically, TP10-treated lungs mainly showed inflammatory tissue infiltration, in contrast to TP2.5-treated lungs, where lysis of the alveolar barrier appeared to be the most characteristic lesion. Our biochemical, cytological, and histological results indicated differential lung toxicity mechanisms elicited by size-fractionated TP, in agreement with other studies performed in in vivo systems that have shown that lung responses to inhaled or instilled particles are affected by particle size. We conclude that lung toxicity induced by TP10 was primarily due to macrophage-mediated inflammatory events, while toxicity induced by TP2.5 appeared to be related more closely to cytotoxicity.

Pleural liquid pressure over the interlobar mediastinal and diaphragmatic surfaces of the lung

Pleural liquid pressure (Pliq) was measured in the interlobar fissures and over the mediastinal apical, cardiac and diaphragmatic surface. When compared to costal values, Pliq was more subatmospheric over the cardiac region at all lung heights by about 5 cm H2O so that a costo-hilar gradient down the interlobar fissures of about 0.7 cm H2O/cm was found. No differences were found for other surfaces. Cardiac values, unlike costal ones, became more subatmospheric on increasing ventilation and heart-rate. On the basis of a Starling equilibrium a costo-hilar gradient of Pliq as well as more negative values in the cardiac surface can be explained if hydrostatic pressure in visceral pleura and/or hydraulic conductivity of parietal pleura are lower on mediastinal as compared to costal side. However the ventilation and heart-beat dependence of Pliq on cardiac region suggest a possible role of lymphatic in setting pleural liquid pressure.

Respiratory Mechanics and Fluid Dynamics After Lung Resection Surgery

Thoracic surgery that requires resection of a portion of lung or of a whole lung profoundly alters the mechanical and fluid dynamic setting of the lung-chest wall coupling, as well as the water balance in the pleural space and in the remaining lung. The most frequent postoperative complications are of a respiratory nature, and their incidence increases the more the preoperative respiratory condition seems compromised. There is an obvious need to identify risk factors concerning mainly the respiratory function, without neglecting the importance of other comorbidities, such as coronary disease. At present, however, a satisfactory predictor of postoperative cardiopulmonary complications is lacking; postoperative morbidity and mortality have remained unchanged in the last 10 years. The aim of this review is to provide a pathophysiologic interpretation of the main respiratory complications of a respiratory nature by relying on new concepts relating to lung fluid dynamics and mechanics. New parameters are proposed to improve evaluation of respiratory function from pre- to the early postoperative period when most of the complications occur.

Distribution of pulmonary stretch receptors in the intrapulmonary airways of the dog

Abstract Fifty-eight pulmonary stretch receptors from 41 dogs have been localized in the intrapulmonary airways of the left lung through a direct dissection into the lung parenchyma. The intrapulmonary stretch receptors account for 44.4% of the total and their distribution in the intrapulmonary airways was 7.6% in the lobar bronchi, 18.4% in bronchi having a diameter greater than 1 mm and 18.4% in the remaining airways. Of all the receptors 82.8% were at an average distance of 3.1±0.2 cm (S.E.) from the lung root, thus within a volume approximately equal to 1 25 of the end-expiratory volume of the lung. The concentration of stretch receptors along the intrapulmonary airways was calculated from the surface area of the bronchial tree at different levels on the assumption of 2000 receptors from one lung. These data, together with those referring to extrapulmonary airways, show that the concentration nearly doubles going from the upper intrathoracic trachea to the lobar bronchi (from 34.8 receptors/cm 2 to 60.5/cm 2 ) and then sharply decreases to 7.0/cm 2 in bronchi having a diameter greater than 1 mm and 0.2/cm 2 in the smaller intrapulmonary airways.