Jean-Claude Pache

Production of Chemokines by Perivascular Adipose Tissue: A Role in the Pathogenesis of Atherosclerosis?

Objective—Obesity is associated with an increased risk for cardiovascular disease. Although it is known that white adipose tissue (WAT) produces numerous proinflammatory and proatherogenic cytokines and chemokines, it is unclear whether adipose-derived chemotactic signals affect the chronic inflammation in atherosclerosis. Methods and Results—Histological examination showed that perivascular WAT (pWAT) is in close proximity to vascular walls, particularly at sites that have a tendency to develop atherosclerosis. In rodents, the amount of pWAT is markedly increased by a high-fat diet. At a functional level, supernatant from subcutaneous and pWAT strongly induced the chemotaxis of peripheral blood leukocytes. The migration of granulocytes and monocytes was mostly mediated by interleukin-8 and monocyte chemoattractant protein-1, respectively, whereas both chemokines contributed to the migration of activated T cells. Moreover, pWAT produces these chemokines, as shown by immunohistochemistry and by explant culture. The accumulation of macrophages and T cells at the interface between pWAT and the adventitia of human atherosclerotic aortas may reflect this prochemotactic activity of pWAT. Conclusions—Human pWAT has chemotactic properties through the secretion of different chemokines, and we propose that pWAT might contribute to the progression of obesity-associated atherosclerosis.

A key role for NOX4 in epithelial cell death during development of lung fibrosis.

UNLABELLED The pathogenesis of pulmonary fibrosis is linked to oxidative stress, possibly generated by the reactive oxygen species (ROS) generating NADPH oxidase NOX4. Epithelial cell death is a crucial early step in the development of the disease, followed only later by the fibrotic stage. We demonstrate that in lungs of patients with idiopathic lung fibrosis, there is strong expression of NOX4 in hyperplastic alveolar type II cells. AIM To study a possible causative role of NOX4 in the death of alveolar cells, we have generated NOX4-deficient mice. RESULTS Three weeks after administration of bleomycin, wild-type (WT) mice developed massive fibrosis, whereas NOX4-deficient mice displayed almost normal lung histology, and only little Smad2 phosphorylation and accumulation of myofibroblasts. However, the protective effects of NOX4 deficiency preceded the fibrotic stage. Indeed, at day 7 after bleomycin, lungs of WT mice showed massive increase in epithelial cell apoptosis and inflammation. In NOX4-deficient mice, no increase in apoptosis was observed, whereas inflammation was comparable to WT. In vitro, NOX4-deficient primary alveolar epithelial cells exposed to transforming growth factor-β(1) did not generate ROS and were protected from apoptosis. Acute treatment with the NOX inhibitors also blunted transforming growth factor-β(1)-induced apoptosis. CONCLUSION ROS generation by NOX4 is a key player in epithelial cell death leading to pulmonary fibrosis.

Keratinocyte Growth Factor Protects Alveolar Epithelium and Endothelium from Oxygen-Induced Injury in Mice

Keratinocyte growth factor (KGF) has been used successfully to prevent alveolar damage induced by oxygen exposure in rodents. However, this treatment was used intratracheally and before oxygen exposure, which limited its clinical application. In the present study, mice were treated with the recombinant human KGF intravenously before (days -2 and -1) or during (days 0 and +1) oxygen exposure. In both cases, lung damage was attenuated. KGF increased the number of cells incorporating bromodeoxyuridine (BrdU) in the septa and in bronchial epithelium of air-breathing mice but not of oxygen-exposed mice, indicating that the protective effect of KGF is not necessarily associated with proliferation. Oxygen-induced damage of alveolar epithelium and, unexpectedly, of endothelium was prevented by KGF treatment as seen by electron microscopy. We investigated the effect of KGF on different mechanisms known to be involved in oxygen toxicity. The induction of p53, Bax, and Bcl-x mRNAs during hyperoxia was to a large extent prevented by KGF. Surfactant proteins A and B mRNAs were not markedly modified by KGF. The anti-fibrinolytic activity observed in the alveoli during hyperoxia was to a large extent prevented by KGF, most probably by suppressing the expression of plasminogen activator inhibitor-1 (PAI-1) mRNA and protein. As PAI-1 -/- mice are more resistant to hyperoxia, KGF might act, at least in part, by decreasing the expression of this protease inhibitor and by restoring the fibrinolytic activity into the lungs.

Diagnostic changes as a reason for the increase in papillary thyroid cancer incidence in Geneva, Switzerland

Objective: Several studies have reported upward incidence trends of papillary thyroid cancer. It is unclear whether these trends reflect a real risk increase, by some attributed to iodine supplementation, or an artificial one, due to increased diagnostic activity or changed histological criteria. This study examines if these artificial factors explain the increased papillary thyroid cancer incidence in the Swiss canton of Geneva. Methods: All thyroid carcinomas (n = 436) recorded between 1970 and 1998 at the Geneva Cancer Registry were considered. European age-adjusted incidence trends were estimated using linear regression analysis. For papillary cancers we evaluated diagnostic modalities and way of presentation (in particular microcarcinoma < 1 cm or silent carcinoma). In addition, we reviewed the histological slides of follicular carcinomas. Results: Papillary thyroid cancer incidence increased significantly from 0.7 to 1.8/100,000 for men and from 3.1 to 4.3/100,000 for women between 1970–74 and 1995–98. The proportion of microcarcinomas and silent carcinomas increased from 17% to 24% between 1970–79 and 1990–98. At histological review, follicular cancers were more often reclassified as papillary cancer for cases diagnosed between 1970 and 1979 than for cases diagnosed between 1990 and 1998 (45% vs 25%, p = n.s.). Conclusions: The increasing papillary thyroid cancer incidence seems mainly due to changes in histological diagnostic criteria and, to a lesser extent, to increased diagnostic activity. If confirmed, the results of this study indicate that fears of increasing incidence rates of papillary thyroid cancer should not prevent implementation of adequate programs of iodine supplementation in the many areas where iodine deficiency still prevails.

A Prospective Hospital-Based Study of the Clinical Impact of Non–Severe Acute Respiratory Syndrome (Non-SARS)–Related Human Coronavirus Infection

Abstract Background. In addition to the human coronaviruses (HCoVs) OC43 and 229E, which have been known for decades to cause infection in humans, 2 new members of this genus have recently been identified: HCoVs NL63 and HKU1. Their impact as a cause of respiratory tract disease in adults at risk for complications needs to be established. Methods. We prospectively assessed the clinical impact of coronavirus infection (excluding cases of severe acute respiratory syndrome) among hospitalized adults. All patients with respiratory disease for whom bronchoalveolar lavage was performed were screened by reverse-transcriptase polymerase chain reaction for the presence of all 4 HCoVs. Results. HCoV was identified in 29 (5.4%) of 540 bronchoalveolar lavage fluid specimens from 279 subjects (mean age, 51 years; 63% male). HCoV OC43 was identified most frequently (12 isolates), followed by 229E (7 isolates), NL63 (6 isolates), and HKU1 (4 isolates). In all, 372 (69%) of 540 bronchoalveolar lavage fluid specimens were negative for bacteria, and 2 persons were coinfected with other respiratory viruses. Transplantation was the most common underlying condition. Of the 29 patients who had HCoV identified in their bronchoalveolar lavage fluid specimens, 9 (31%) were hospitalized in the intensive care unit, 22 (76%) presented to the hospital with acute respiratory symptoms, 16 (55%) presented with cough and/or sputum, 13 (45%) presented with dyspnea, 16 (55%) had experienced prior respiratory infection, and 18 (62%) had a new infiltrate that was visible on chest radiograph. The most frequent final diagnosis was a lower respiratory tract infection. Conclusions. The recently discovered HCoVs NL63 and HKU1 contribute significantly to the overall spectrum of coronavirus infection. Our study also suggests that coronaviruses contribute to respiratory symptoms in most cases.

Contribution of transmembrane tumor necrosis factor to host defense against Mycobacterium bovis bacillus Calmette-guerin and Mycobacterium tuberculosis infections.

To study the specific role of transmembrane tumor necrosis factor (TmTNF) in host defense mechanisms against bacillus Calmette-Guerin (BCG) and Mycobacterium tuberculosis infections, we compared the immune responses of TNF/lymphotoxin (LT)-alpha(-/-) mice expressing a noncleavable transgenic TmTNF (TmTNF tg) to those of TNF/LT-alpha(-/-) and wild-type mice. Susceptibility of TNF/LT-alpha(-/-) mice to BCG infection was associated with impaired induction of systemic RANTES but not of monocyte chemoattractant protein 1 (MCP-1), the development of excessive local and systemic Th1-type immune responses, and a substantially reduced inducible nitric oxide synthase (iNOS) activity. Resistance of TmTNF tg mice to BCG infection was associated with efficient activation of iNOS in granulomas and with the regulated release of local and systemic chemokines and Th1-type cytokines. However, M. tuberculosis infection of TmTNF tg mice resulted in longer survival and enhanced resistance compared to TNF/LT-alpha(-/-) mice but higher sensitivity than wild-type mice. TmTNF tg mice exhibited reduced pulmonary iNOS expression and showed an exacerbated cellular infiltration in the lungs despite a modest bacillary content. Our data thus indicate a role for TmTNF in host defense against mycobacteria by contributing to induction and regulation of Th1-type cytokine and chemokine expression leading to development of bactericidal granulomas expressing iNOS, which critically determines susceptibility versus resistance of the host to mycobacterial infections.

Claudin-1 and claudin-5 expression patterns differentiate lung squamous cell carcinomas from adenocarcinomas.

We investigated the expression of tight junction proteins in human lung squamous cell carcinomas and adenocarcinomas by immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). We found a statistically significant correlation between diagnosis and positivity of tumors with either claudin (CLDN)-1 or CLDN-5. Squamous cell carcinomas and basal cells of bronchial epithelium were positive for CLDN-1 and negative for CLDN-5, whereas adenocarcinomas, normal cylindrical cells and pneumocytes were positive for CLDN-5 and negative for CLDN-1, suggesting different pathways in tumor development and progression. CLDN-4 and ZO-1 staining were detected in both types of tumors, whereas cingulin (CGN) was not detected in squamous cell carcinomas. Quantitative RT-PCR was used to evaluate changes in transcript levels for a large panel of tight junction proteins. In squamous cell carcinomas, we observed statistically significant decreases in the mRNA levels of JAM-1, occludin, CLDN-3, CLDN-4, CLDN-7, CGN, ZO-2 and ZO-3, and an increase in CLDN-1 mRNA. In adenocarcinomas, when transcript levels were compared with bronchial cells, we observed statistically significant decreases in the mRNA levels of CLDN-1, CLDN-3, CLDN-4, CLDN-7, ZO-2 and ZO-3. These results indicate that characterization of tight junction protein expression in human lung tumors can be an additional diagnostic tool and provide new insights on their histogenesis.

Primary hyperparathyroidism: can parathyroid carcinoma be anticipated on clinical and biochemical grounds? Report of nine cases and review of the literature.

BackgroundParathyroid carcinoma (PC) mimics benign primary hyperparathyroidism (PHP), but the diagnosis of PC is seldom available at the time of the first operation. Because PC is plagued by recurrences usually beyond cure, one may wonder whether some of these could be prevented by more extensive resections initially, i.e., if the diagnosis of PC were available at that time.MethodsOver a 25-year period, 311 consecutive patients with PHP underwent operation in our department: 302 had benign disease (adenomas or hyperplasias), and 9 had PC. Several clinical parameters, serum calcium and parathyroid hormone (PTH) levels, and the weight of the parathyroid tumor removed were compared in both groups. Receiver operating characteristic curves and logistical regression analyses were used to distinguish PC from benign PHP.ResultsEight of 9 patients with PC had symptoms, versus 238 (79%) of 302 with benign PHP (not significant). In the PC subgroup, serum calcium and PTH levels and the tumor weights of the parathyroid glands removed were significantly higher than in the benign PHP cohort, even if these three parameters were regularly flawed by low positive predictive values (14%, 20%, and 15%, respectively).ConclusionsSerum calcium, PTH levels, and tumor weights were significantly greater in the PC subgroup, even if not invariably in a discriminatory way. However, when PTH is <4 times the upper limit of normal and tumor weight is <1.9 g, the probability of PC is nil.

Cytomorphologic Features of Poorly Differentiated Thyroid Carcinoma: A Multi-Institutional Analysis of 40 Cases

Poorly differentiated thyroid carcinoma (PDTC) is an uncommon and aggressive malignancy. Despite the significant clinical implications of a diagnosis of PDTC, its cytomorphologic features have not been well defined. Statistical analysis was applied to a series of 40 PDTCs to identify a specific set of cytomorphologic features that characterized these tumors on fine‐needle aspiration biopsy (FNAB).

Matrix metalloproteinases correlate with alveolar-capillary permeability alteration in lung ischemia-reperfusion injury

Background. Matrix metalloproteinases (MMPs) are able to degrade the endothelial basal lamina and increase vascular permeability. Methods. In a porcine model of isolated-reperfused lung, we studied the alveolar-capillary permeability and the zymographic expression of MMP-9 and MMP-2 in the bronchoalveolar lavage fluid of lungs submitted ex vivo to ischemia in three preservation solutions [modified Euro-Collins (EC), low-potassium-dextran, modified-blood]. Twenty-two pigs were randomly divided into three groups according to the preservation solution used. One lung of each pig was rapidly reperfused and analyzed (control lung) although the other lung was reperfused and analyzed after 8 hr of ischemia (ischemic lung). Results. Alveolar-capillary permeability, evaluated by the transferrin leak index, was increased after 8 hr of ischemia compared with controls in the three groups, but was significantly higher in the modified EC group. In the EC group, after 8 hr of ischemia, both proMMP-9 and MMP-9 increased significantly (8.8- and 22-fold, respectively) compared with controls and this increase correlated with the transferrin leak index. Neither proMMP-9 nor MMP-9 increased with the other two preservation solutions. The MMP-2 increase after ischemia was smaller and was also restricted to the EC group. Conclusion. MMP expression is enhanced during lung ischemia-reperfusion, especially in the presence of EC and this phenomenon correlates with the alteration of alveolar-capillary permeability.