Discovery of the TLR7/8 Antagonist MHV370 for Treatment of Systemic Autoimmune Diseases

Toll-like receptor (TLR) 7 and TLR8 are endosomal sensors of the innate immune system that are activated by GU-rich single stranded RNA (ssRNA). Multiple genetic and functional lines of evidence link chronic activation of TLR7/8 to the pathogenesis of systemic autoimmune diseases (sAID) such as Sjögren's syndrome (SjS) and systemic lupus erythematosus (SLE). This makes targeting TLR7/8-induced inflammation with small-molecule inhibitors an attractive approach for the treatment of patients suffering from systemic autoimmune diseases. Here, we describe how structure-based optimization of compound 2 resulted in the discovery of 34 (MHV370, (S)-N-(4-((5-(1,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-4-yl)-3-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridin-1-yl)methyl)bicyclo[2.2.2]octan-1-yl)morpholine-3-carboxamide). Its in vivo activity allows for further profiling toward clinical trials in patients with autoimmune disorders, and a Phase 2 proof of concept study of MHV370 has been initiated, testing its safety and efficacy in patients with Sjögren's syndrome and mixed connective tissue disease.

BRD9 degraders as chemosensitizers in acute leukemia and multiple myeloma

Bromodomain-containing protein 9 (BRD9), an essential component of the SWI/SNF chromatin remodeling complex termed ncBAF, has been established as a therapeutic target in a subset of sarcomas and leukemias. Here, we used novel small molecule inhibitors and degraders along with RNA interference to assess the dependency on BRD9 in the context of diverse hematological malignancies, including acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and multiple myeloma (MM) model systems. Following depletion of BRD9 protein, AML cells undergo terminal differentiation, whereas apoptosis was more prominent in ALL and MM. RNA-seq analysis of acute leukemia and MM cells revealed both unique and common signaling pathways affected by BRD9 degradation, with common pathways including those associated with regulation of inflammation, cell adhesion, DNA repair and cell cycle progression. Degradation of BRD9 potentiated the effects of several chemotherapeutic agents and targeted therapies against AML, ALL, and MM. Our findings support further development of therapeutic targeting of BRD9, alone or combined with other agents, as a novel strategy for acute leukemias and MM.

Flowering resources modulate the sensitivity of bumblebees to a common fungicide

Bees are exposed to various stressors, including pesticides and lack of flowering resources. Despite potential interactions between these stressors, the impacts of pesticides on bees are generally assumed to be consistent across bee-attractive crops, and regulatory risk assessments of pesticides neglect interactions with flowering resources. Furthermore, impacts of fungicides on bees are rarely examined in peer-reviewed studies, although these are often the pesticides that bees are most exposed to. In a full-factorial semi-field experiment with 39 large flight cages, we assessed the single and combined impacts of the globally used azoxystrobin-based fungicide Amistar® and three types of flowering resources (Phacelia, buckwheat, and a floral mix) on Bombus terrestris colonies. Although Amistar is classified as bee-safe, Amistar exposure through Phacelia monocultures reduced adult worker body mass and colony growth (including a 55% decline in workers and an 88% decline in males), while the fungicide had no impact on colonies in buckwheat or the floral mix cages. Furthermore, buckwheat monocultures hampered survival and fecundity irrespective of fungicide exposure. This shows that bumblebees require access to complementary flowering species to gain both fitness and fungicide tolerance and that Amistar impacts are flowering resource-dependent. Our findings call for further research on how different flowering plants affect bees and their pesticide tolerance to improve guidelines for regulatory pesticide risk assessments and inform the choice of plants that are cultivated to safeguard pollinators.

P-246 A novel non-invasive tool for oocyte selection using gene expression and artificial intelligence

Study question

Is it possible to predict top quality embryos through gene expression analysis of cumulus cells and artificial intelligence before fertilization?

Summary answer

The artificial inteligence based tool OsteraTest is able to predict the ability of the oocyte to develop into a top quality blastocyst with 86% accuracy.

What is known already

Proper oocyte selection is an important bottleneck for In Vitro Fertilization (IVF) success. Nowadays, oocyte selection relies mainly in morphological analyses, which is not an unbiased method and may fail to reveal the real competence status of gametes. Cumulus oophorus cells (CC) are somatic cells that surround the oocyte at the antral follicle. It is directly involved in oocyte maturation and development, and thus is a valuable non-invasive source of biological information regarding the oocyte’s health. Artificial intelligence can be used to identify key biological processes and markers of interest through machine learning methods and could thus be applied.

Study design, size, duration

This is a prospective study that included data from 80 CC samples retrieved from publicly available microarray data (GSE27377) in the algorithm construction phase and 65 CC samples from each oocyte of 26 patients submitted to Intracytoplasmic Sperm Injection (ICSI) in validation phase. Samples were divided in two groups: CCs from oocytes that developed into top quality blastocysts in day 5 after ICSI and CCs from oocytes that presented arrested development.

Participants/materials, setting, methods

Samples were submitted to real time quantitative PCR with 25 target genes. Afterwards, gene expression levels for each gene and sample were submitted to the final algorithm, that was computed into a software, the OsteraTest, in a double-blind approach. The software indicated the development potential of each oocyte and this ranking was compared to the embryologist’s day 5 blastocyst classification according to Gardner.

Main results and the role of chance

The bioinformatic approach implemented resulted in the OsteraTest, composed of 8 machine learning models using a 25-gene network that altogether can predict oocyte quality, thus representing a very complex assembly. The software presented more than 86% accuracy in predicting the oocytes developmental capacity into a top-quality day 5 blastocyst. Top quality blastocysts present over 80% chance of resulting in a healthy pregnancy and live birth, and so this approach could be further used as a pregnancy potential predictor after a prospective study is conducted, analyzing CCs from oocytes that were further fertilized, developed into blastocysts and transferred in single embryo transfers. This tool can contribute greatly to improve success rates in IVF procedures and to assess egg quality in egg freezing procedures, providing information about the gametes potential even years before its use.

Limitations, reasons for caution

A large-scale, prospective, randomized study is necessary for further validation of these findings and to confirm the validity of the OsteraTest in the clinical environment. Such study is now being conducted in our lab.

Wider implications of the findings

The OsteraTest proved to be a valuable non-invasive tool to predict embryo formation and oocyte capacity even before fertilization.It can enable the clinics to anticipate successful treatments and provide a predictive report for oocyte freezing patients.

Trial registration number

#68081017.2.0000.5347

Structure-Based Optimization of a Fragment-like TLR8 Binding Screening Hit to an In Vivo Efficacious TLR7/8 Antagonist

Inappropriate activation of TLR7 and TLR8 is linked to several autoimmune diseases, such as lupus erythematosus. Here we report on the efficient structure-based optimization of the inhibition of TLR8, starting from a co-crystal structure of a small screening hit. Further optimization of the physicochemical properties for cellular potency and expansion of the structure-activity relationship for dual potency finally resulted in a highly potent TLR7/8 antagonist with demonstrated in vivo efficacy after oral dosing.

Development of autotaxin inhibitors: A series of tetrazole cinnamides

A series of inhibitors of Autotaxin (ATX) have been developed from a high throughput screening hit, 1a, which shows an alternative binding mode to known catalytic site inhibitors. Selectivity over the hERG channel and microsomal clearance were dependent on the lipophilicity of the compounds, and this was optimised by reduction of clogD whilst maintaining high affinity ATX inhibition. Compound 15a shows good oral exposure, and concentration dependent inhibition of formation of LPA in vivo, as shown in pharmacokinetic-pharmacodynamic (PK/PD) experiments.

Target-Based Identification and Optimization of 5-Indazol-5-yl Pyridones as Toll-like Receptor 7 and 8 Antagonists Using a Biochemical TLR8 Antagonist Competition Assay

Inappropriate activation of endosomal TLR7 and TLR8 occurs in several autoimmune diseases, in particular systemic lupus erythematosus (SLE). Herein, the development of a TLR8 antagonist competition assay and its application for hit generation of dual TLR7/8 antagonists are reported. The structure-guided optimization of the pyridone hit 3 using this biochemical assay in combination with cellular and TLR8 cocrystal structural data resulted in the identification of a highly potent and selective TLR7/8 antagonist (27) with in vivo efficacy. The two key steps for optimization were (i) a core morph guided by a TLR7 sequence alignment to achieve a dual TLR7/8 antagonism profile and (ii) introduction of a fluorine in the piperidine ring to reduce its basicity, resulting in attractive oral pharmacokinetic (PK) properties and improved TLR8 binding affinity.

Development of autotaxin inhibitors: A series of zinc binding triazoles

A series of inhibitors of Autotaxin (ATX) has been developed using the binding mode of known inhibitor, PF-8380, as a template. Replacement of the benzoxazolone with a triazole zinc-binding motif reduced crystallinity and improved solubility relative to PF-8380. Modification of the linker region removed hERG activity and led to compound 12 - a selective, high affinity, orally-bioavailable inhibitor of ATX. Compound 12 concentration-dependently inhibits autotaxin and formation of LPA in vivo, as shown in pharmacokinetic-pharmacodynamic experiments.

Caspases cleave and inhibit the microRNA processing protein DiGeorge Critical Region 8

DGCR8 (DiGeorge Critical Region 8) is an essential microRNA (miRNA) processing protein that recognizes primary transcripts of miRNAs (pri-miRNAs) and triggers their cleavage by the Drosha nuclease. We previously found that Fe(III) heme binds and activates DGCR8. Here we report that in HeLa cells, DGCR8 undergoes two proteolytic events that produce two C-terminal fragments called DGCR8(C1) and DGCR8(C2) , respectively. DGCR8(C2) accumulates during apoptosis and is generated through cleavage by a caspase. The caspase cleavage site is located in the central loop of the heme-binding domain. Cleavage of DGCR8 by caspase-3 in vitro results in loss of the otherwise tightly bound Fe(III) heme cofactor, dissociation of the N- and C-terminal proteolytic fragments, and inhibition of the pri-miRNA processing activity. These results reveal an intrinsic mechanism in the DGCR8 protein that seems to have evolved for regulating miRNA processing via association with Fe(III) heme and proteolytic cleavage by caspases. Decreased expression of miRNAs has been observed in apoptotic cells, and this change was attributed to caspase-mediated cleavage of a down-stream miRNA processing nuclease Dicer. We suggest that both the Drosha and Dicer cleavage steps of the miRNA maturation pathway may be inhibited in apoptosis and other biological processes where caspases are activated.

Structure of the dimerization domain of DiGeorge critical region 8

Maturation of microRNAs (miRNAs, approximately 22nt) from long primary transcripts [primary miRNAs (pri-miRNAs)] is regulated during development and is altered in diseases such as cancer. The first processing step is a cleavage mediated by the Microprocessor complex containing the Drosha nuclease and the RNA-binding protein DiGeorge critical region 8 (DGCR8). We previously reported that dimeric DGCR8 binds heme and that the heme-bound DGCR8 is more active than the heme-free form. Here, we identified a conserved dimerization domain in DGCR8. Our crystal structure of this domain (residues 298-352) at 1.7 A resolution demonstrates a previously unknown use of a WW motif as a platform for extensive dimerization interactions. The dimerization domain of DGCR8 is embedded in an independently folded heme-binding domain and directly contributes to association with heme. Heme-binding-deficient DGCR8 mutants have reduced pri-miRNA processing activity in vitro. Our study provides structural and biochemical bases for understanding how dimerization and heme binding of DGCR8 may contribute to regulation of miRNA biogenesis.

DGCR8 recognizes primary transcripts of microRNAs through highly cooperative binding and formation of higher-order structures

DiGeorge critical region 8 (DGCR8) is essential for maturation of microRNAs (miRNAs) in animals. In the cleavage of primary transcripts of miRNAs (pri-miRNAs) by the Drosha nuclease, the DGCR8 protein directly binds and recognizes pri-miRNAs through a mechanism currently controversial. Our previous data suggest that DGCR8 trimerizes upon cooperative binding to pri-mir-30a. However, a separate study proposed a model in which a DGCR8 molecule contacts one or two pri-miRNA molecules using its two double-stranded RNA binding domains. Here, we extensively characterized the interaction between DGCR8 and pri-miRNAs using biochemical and structural methods. First, a strong correlation was observed between the association of DGCR8 with pri-mir-30a and the rate of pri-miRNA processing in vitro. Second, we show that the high binding cooperativity allows DGCR8 to distinguish pri-miRNAs from a nonspecific competitor with subtle differences in dissociation constants. The highly cooperative binding of DGCR8 to a pri-miRNA is mediated by the formation of higher-order structures, most likely a trimer of DGCR8 dimers, on the pri-miRNA. These properties are not limited to its interaction with pri-mir-30a. Furthermore, the amphipathic C-terminal helix of DGCR8 is important both for trimerization of DGCR8 on pri-miRNAs and for the cleavage of pri-miRNAs by Drosha. Finally, our three-dimensional model from electron tomography analysis of the negatively stained DGCR8-pri-mir-30a complex directly supports the trimerization model. Our study provides a molecular basis for recognition of pri-miRNAs by DGCR8. We further propose that the higher-order structures of the DGCR8-pri-miRNA complexes trigger the cleavage of pri-miRNAs by Drosha.

Structure and proposed activity of a member of the VapBC family of toxin-antitoxin systems. VapBC-5 from Mycobacterium tuberculosis

In prokaryotes, cognate toxin-antitoxin pairs have long been known, but no three-dimensional structure has been available for any given complex from Mycobacterium tuberculosis. Here we report the crystal structure and activity of a member of the VapBC family of complexes from M. tuberculosis. The toxin VapC-5 is a compact, 150 residues, two domain alpha/beta protein. Bent around the toxin is the VapB-5 antitoxin, a 33-residue alpha-helix. Assays suggest that the toxin is an Mg-enabled endoribonuclease, inhibited by the antitoxin. The lack of DNase activity is consistent with earlier suggestions that the complex represses its own operon. Furthermore, analysis of the interactions in the binding of the antitoxin to the toxin suggest that exquisite control is required to protect the bacteria cell from toxic VapC-5.

MicroRNA biogenesis: there's more than one way to skin a cat

microRNAs (miRNAs) are extensively involved in developmental programming. Some miRNAs are highly conserved, while others are lineage specific. All miRNAs maturate through a series of processing steps. Here we review recent progresses in the studies of early steps in miRNA biogenesis, focusing on animal systems. The miRNA maturation pathways are surprisingly diverse, involving transcription by RNA polymerase II or III, cleavage by the Drosha nuclease or the spliceosome, and sometimes modifications by the adenosine deaminase ADAR. The relationship between the diversity in miRNA biogenesis and the apparently rapid evolution of miRNA genes and functions is discussed.

Heme is involved in microRNA processing

MicroRNAs (miRNAs) regulate the expression of a large number of protein-coding genes. Their primary transcripts (pri-miRNAs) have to undergo multiple processing steps to reach the functional form. Little is known about how the processing of miRNAs is modulated. Here we show that the RNA-binding protein DiGeorge critical region-8 (DGCR8), which is essential for the first processing step, is a heme-binding protein. The association with heme promotes dimerization of DGCR8. The heme-bound DGCR8 dimer seems to trimerize upon binding pri-miRNAs and is active in triggering pri-miRNA cleavage, whereas the heme-free monomer is much less active. A heme-binding region of DGCR8 inhibits the pri-miRNA-processing activity of the monomer. This putative autoinhibition is overcome by heme. Our finding that heme is involved in pri-miRNA processing suggests that the gene-regulation network of miRNAs and signal-transduction pathways involving heme might be connected.

The Structure of a Mycobacterial Outer-Membrane Channel

Mycobacteria have low-permeability outer membranes that render them resistant to most antibiotics. Hydrophilic nutrients can enter by way of transmembrane-channel proteins called porins. An x-ray analysis of the main porin from Mycobacterium smegmatis, MspA, revealed a homooctameric goblet-like conformation with a single central channel. This is the first structure of a mycobacterial outer-membrane protein. No structure-related protein was found in the Protein Data Bank. MspA contains two consecutive beta barrels with nonpolar outer surfaces that form a ribbon around the porin, which is too narrow to fit the thickness of the mycobacterial outer membrane in contemporary models.

Insulin-like growth factor (IGF)-1 and IGF binding protein-1 and -3 in the follicular fluid of infertile patients with endometriosis

BACKGROUND

Endometriosis is associated with pituitary-ovarian axis dysfunction. The study of the follicular fluid in patients with endometriosis is important to elucidate the pathophysiological mechanism of this disease. The objective of this present paper was to analyse the dosages of insulin-like growth factor-1 (IGF-1) and IGF binding protein-1 and 3 (IGFBP-1 and IGFBP-3) in the follicular fluid environment of infertile patients with endometriosis.

METHODS

A total of 41 infertile patients undergoing IVF between January 1999 and January 2000 participated in the cross-sectional prospective study. Patients were divided into three groups: group I, minimal/mild endometriosis (n = 12); group II, moderate/severe endometriosis (n = 10); and group III, tubal obstruction (n = 19). The ultra-short protocol was used in association with recombinant FSH for ovulation induction. Follicular fluid analysis was performed using radioimmunoassay with specific kits.

RESULTS

Follicular fluid IGF-1 and IGFBP-3 levels were not significantly different among the groups; however, follicular fluid IGFBP-1 levels were lower in those patients with moderate/severe endometriosis (P < 0.05). Comparison of ovulation induction time, number of recombinant FSH units, number of follicles, oocytes and embryos, and fertilization and gestation/cycle rates showed non-significant differences.

CONCLUSION

Infertile patients with moderate/severe endometriosis, which is associated with ovulatory dysfunction, presented lower levels of IGFBP-1 in the follicular fluid when undergoing IVF.

The obesity-hypoventilation syndrome revisited: a prospective study of 34 consecutive cases

STUDY OBJECTIVES

Obesity has many detrimental effects on the respiratory function and may lead to chronic hypoventilation in some patients, an association known as the obesity-hypoventilation syndrome (OHS). In many cases, patients with OHS also have sleep apneas. Hereafter, we describe several features of a cohort (n = 34) of patients with OHS and show the comparisons with a large cohort (n = 220) of patients with obstructive sleep apnea syndrome (OSAS). We compare also OHS patients with a group of patients with the association of OSAS and COPD, also known as "overlap" patients.

DESIGN

Descriptive analysis of prospectively collected clinical data.

SETTING

Respiratory care unit and sleep laboratory of university hospital.

RESULTS

In OHS patients, OSAS was present in most of the cases (23 of 26 patients). However, in three patients, OHS was not associated with OSAS, showing that obesity per se may lead to chronic hypoventilation. As expected by definition, OHS patients had, on average the worst diurnal arterial blood gas measurements, compared to the other groups. For the OHS patients, the mean diurnal PaO(2) was 59 +/- 7 mm Hg, which was significantly different from the PaO(2) of the OSAS patients (75 +/- 10 mm Hg; p = 0,001) but also from the overlap patients (66 +/- 10 mm Hg; p = 0.015). Pulmonary hypertension (ie, mean pulmonary artery pressure > 20 mm Hg) was more frequent in OHS patients than in "pure" OSAS patients (58% vs 9%; p = 0.001).

CONCLUSION

Patients with OSAS and chronic respiratory insufficiency had in most cases an associated OHS or COPD. Patients with OHS were older than patients with pure OSAS. They had mild-to-moderate degrees of restrictive ventilatory pattern due to obesity. Severe gas exchange impairment and pulmonary hypertension were quite frequent. The association of OHS and OSAS was the rule. However, in three patients, OHS was not associated with OSAS, suggesting that OHS is an autonomous disease.

"Natural history" of pulmonary hypertension in a series of 131 patients with chronic obstructive lung disease

The prognostic value and the evolution of pulmonary hypertension (PH) in patients with markedly hypoxemic chronic obstructive pulmonary disease (COPD), treated or not with long-term oxygen therapy (LTOT), has been extensively investigated. However, little is known in patients with mildly or moderately hypoxemic COPD not requiring LTOT. Therefore, we assessed the evolution of pulmonary hemodynamics in 131 patients with stable COPD by performing two right heart catheterizations at a mean (+/- SD) time interval of 6.8 +/- 2.9 yr. At inclusion (T0), no patient had PH (i.e., the mean pulmonary artery pressure [Ppa] at rest was < 20 mm Hg). Group 1 included 55 patients without exercising PH and group 2 included 76 patients with exercising PH, defined by a pulmonary arterial pressure (Ppa) > 30 mm Hg during a steady-state 40-W exercise. Group 2 patients compared with group 1 patients had a significantly higher resting Ppa (16 +/- 3 mm Hg versus 14 +/- 2 mm Hg, p = 0.001). At the second catheterization, 33 (25%) patients (9 of 55 in group 1, 24 of 76 in group 2, p = 0.048) showed a resting Ppa > 20 mm Hg, but PH was generally mild, ranging from 20 to 42.5 mm Hg. The mean Ppa at second evaluation was 16 +/- 5 mm Hg in group 1 and 19 +/- 7 mm Hg in group 2 (p = 0.01). The patients who developed resting PH at the second catheterization (T1) had higher resting and exercising Ppa (p = 0.001 and p = 0.002, respectively), and significantly lower resting and exercising Pa(O(2)) (p = 0.005 and p = 0.012, respectively) at T0. Logistic regression analysis showed that resting and exercising Ppa were independent predictors (at T0) for the subsequent development of PH (p = 0.029 and p = 0.027, respectively). The patients who developed resting PH (T1) had a significantly worsening of Pa(O(2)) (from 63.5 mm Hg at T0 to 60 mm Hg at T1, p = 0.047), whereas the Pa(O(2)) as a mean was stable in the remainder (69.5 mm Hg at T0 and T1). These results show the following. The progression of Ppa over time in patients with COPD with mild to moderate hypoxemia is rather slow, the average change for the group as a whole being of + 0.4 mm Hg/yr. Only about 25% of patients with COPD with mild to moderate hypoxemia and without resting PH at the onset will develop PH during a 6-yr follow-up. The patients with exercising PH at the onset have a significantly increased risk of developing PH over time. Only resting and exercising Ppa at the onset are independently related to the subsequent development of PH. However, in individual cases, the models of linear or logistic regression do not allow a pertinent prediction of the level of Ppa or the presence of PH at the second right heart catheterization.

Pulmonary migratory infiltrates and pachypleuritis in a patient with Crohn's disease

Crohn's disease can be associated with several respiratory manifestations. We report here a case of pulmonary migratory infiltrates associated with bilateral pleural thickening and peripheral eosinophilia. The histopathological findings show an association of necrotizing nodules, eosinophilic infiltration in the non-abscessed lung tissue, areas of non-caseating epithelioid granulomas, and an extensive pleural fibrosis. The different histopathological findings are detailed and the responsibility of either Crohn's disease or treatment by mesalazine is discussed.

Platypnea-orthodeoxia syndrome related to an aortic aneurysm combined with an aneurysm of the atrial septum

We report the case of a 71-year-old man bearing a severe right-to-left shunt through a patent foramen ovale in the absence of elevated right-sided heart or pulmonary artery pressures. He presented with platypnea-orthodeoxia syndrome, but he had no pulmonary or extracardiac diseases that are known to be associated with this syndrome. Chest radiography showed a bulky aneurysm of the thoracic aorta. A peripheral contrast transesophageal echocardiography demonstrated a large right-to-left shunt through a patent foramen ovale. In addition, the atrial septum was severely deformed by an aneurysm including this patent foramen ovale. We hypothesized that the opening of the foramen ovale was the result of a mechanical deformation of the atrial septum by two contributing factors: the aneurysm of the thoracic aorta and the aneurysm of the septum itself.

Predictive factors of hospitalization for acute exacerbation in a series of 64 patients with chronic obstructive pulmonary disease

Hospitalizations for acute exacerbation in patients with chronic obstructive pulmonary disease (COPD) have a great impact on health care expenditure. The aim of this study was to look at predictive factors of hospitalization for acute exacerbation in a group of patients with moderate to severe COPD. During the year 1994, we included 64 patients with COPD in this study. At inclusion, the patients being in a stable state, we performed a complete evaluation of their clinical, spirometric, gasometric, and pulmonary hemodynamic characteristics. All patients were followed during a period of at least 2.5 yr. We recorded the intervals free of hospitalization for exacerbation and realized an analysis of the proportional hazards not to be hospitalized using the Kaplan-Meier method. Univariate analysis using the log-rank test showed that the risk of being hospitalized was significantly increased in patients with COPD with a low body mass index (BMI <= 20 kg/m2, p = 0.015) and in patients with a limited 6-min walk distance (<= 367 m, p = 0. 045). But above all, the risk of hospitalization for acute exacerbation was significantly increased by gas exchange impairment and pulmonary hemodynamic worsening: PaO2 <= 65 mm Hg versus PaO2 > 65 mm Hg, p = 0.005; PaCO2 > 44 mm Hg versus PaCO2 <= 44 mm Hg, p = 0.005; and mean pulmonary artery pressure ( Ppa) at rest > 18 mm Hg versus Ppa <= 18 mm Hg, p = 0.0008. Neither age, nor the association of one or more comorbidities with COPD, nor the smoking habits had a significant impact on the risk of hospitalization in our study. Multivariate analysis showed that only PaCO2 and Ppa were independently related to the risk of hospitalization for acute exacerbation of COPD. We conclude that chronic hypercapnic respiratory insufficiency and pulmonary hypertension are predictive factors of hospitalization for acute exacerbation in COPD patients.

[Chronic respiratory insufficiency: evaluation, evolution, prognosis]

Chronic respiratory failure (CRF) is a major cause of morbidity and mortality. It is estimated that in France at least 60,000 patients exhibit severe CRF and that about 15,000 patients die each year from CRF. Chronic obstructive pulmonary disease (COPD) (chronic obstructive bronchitis, emphysema and their association) is by far the first cause of CRF (90% of the cases). The clinical picture of CRF depends on the causal disease, but exertional dyspnea is observed in almost all patients. Pulmonary function testing allows to assess whether the ventilatory defect is obstructive (COPD), restrictive or mixed. Severe CRF is usually defined by a Pa02 < 55 mmHg, in a stable state of the disease, with or without hypercapnia (PaC02 > 45 mmHg). The two major complications of CRF are acute exacerbations of the disease, with clinical and gasometric worsening, and pulmonary hypertension which may lead with time to right heart failure. Prognosis is poor in CRF since the 5 year survival rate is of 50% in COPD patients. Under long-term oxygen therapy (LTOT) the survival rate has been somewhat improved, being of 60-65% at 5 years. The best prognostic indices in CRF complicating COPD are the level of FEV1, Pa02, PaC02, the level of pulmonary artery mean pressure (PAP) and age. In COPD patients under LTOT the best prognostic indices are PAP and age.

Regulation of endothelin-1 at rest and during a short steady-state exercise in 21 COPD patients

Endothelin-1 (ET-1) is a vasoconstrictive peptide which may play a relevant role in the pathogenesis of pulmonary hypertension (PH) in COPD patients. We assessed the correlations of plasmatic ET-1 levels with pulmonary function data, arterial blood gases and pulmonary haemodynamics in 21 COPD patients with moderate to severe airway obstruction (FEV1: 1.19+/-0.49 l, mean+/-SD). There were 11 hypoxemic patients (PaO2 <65 mmHg). Six patients had resting PH (mean pulmonary artery pressure >/=20 mmHg). Eight patients had exercising PH (PAP >/=30 mmHg) during a short (6 min) 30 W steady state exercise. At rest, arterial ET-1 levels were significantly higher in COPD patients with hypoxemia when compared to those without hypoxemia (16.6+/-2.7 vs. 12.5+/-3.9 pM/l, P=0.02) and in COPD patients with PH when compared to those without PH (16.5+/-3.4 vs. 13+/-3.9 pM/l, P=0.04). Resting arterial ET-1 levels were negatively correlated with PaO2 (r=-0.45, P=0.05). At rest, the differences between mixed venous and arterial ET-1 levels were positively correlated with FEV1 (r=0.54, P=0.024). At exercise, the mean arterial ET-1 level was not significantly different from the mean resting ET-1 level (13.8+/-3.4 vs. 13.3+/-4 p M/l, NS). There were eight COPD patients who had decreasing arterial ET-1 levels between rest and the end of a 6 min exercise, and six COPD patients who had increasing arterial ET-1 levels. These variations of arterial systemic ET-1 levels from rest to exercise were negatively correlated with FEV1 (r=-0.66, P=0.01). We conclude that in COPD patients (1) at rest, arterial ET-1 levels are increased in hypoxemia or pulmonary hypertension and (2) at rest or during exercise, the turn-over of ET-1 may be dependent of the degree of the bronchial obstruction.

Recurrent varicella pneumonia complicating an endogenous reactivation of chickenpox in an HIV-infected adult patient

We report the case of an adult patient with acquired immune deficiency syndrome (AIDS) presenting with acute dyspnoea and cutaneous disseminated lesions suggestive of an atypical varicella. The chest radiograph and the computed tomography (CT)-scan revealed a miliary pneumonia. On a previous serum sample varicella-zoster (VZV)-specific serum immunoglobulin (Ig)G titre was 1/200. A high dose acyclovir treatment was effective, but recurrences occurred twice when the treatment was discontinued. During the first recurrence the polymerase chain reaction (PCR) detected the presence of VZV in the bronchoalveolar lavage (BAL) sample. These findings confirmed the diagnosis of secondary varicella with pulmonary involvement. Secondary varicella pneumonia has not been reported in a human immunodeficiency virus (HIV)-infected adult until now. The use of PCR on a BAL sample was very useful in this case because viral culture remained negative. Recurrences of the varicella pneumonia suggested that a maintenance treatment was required in this deeply immunocompromised patient.

Recurrent varicella pneumonia complicating an endogenous reactivation of chickenpox in an HIV-infected adult patient

We report the case of an adult patient with acquired immune deficiency syndrome (AIDS) presenting with acute dyspnoea and cutaneous disseminated lesions suggestive of an atypical varicella. The chest radiograph and the computed tomography (CT)-scan revealed a miliary pneumonia. On a previous serum sample varicella-zoster (VZV)-specific serum immunoglobulin (Ig)G titre was 1/200. A high dose acyclovir treatment was effective, but recurrences occurred twice when the treatment was discontinued. During the first recurrence the polymerase chain reaction (PCR) detected the presence of VZV in the bronchoalveolar lavage (BAL) sample. These findings confirmed the diagnosis of secondary varicella with pulmonary involvement. Secondary varicella pneumonia has not been reported in a human immunodeficiency virus (HIV)-infected adult until now. The use of PCR on a BAL sample was very useful in this case because viral culture remained negative. Recurrences of the varicella pneumonia suggested that a maintenance treatment was required in this deeply immunocompromised patient.

Migratory pulmonary infiltrates in a patient treated with sotalol

Beta-blockers may induce several types of adverse respiratory reaction such as asthma, interstitial lung disease with or without pleural effusion, systemic lupus erythematosus or hypersensitivity pneumonitis. More recently, bronchiolitis obliterans with organizing pneumonia (BOOP) has been described. We report here on pulmonary migratory infiltrates with combined histopathological features of both BOOP and eosinophilic pneumonia in a woman treated with sotalol long-term. The patient improved only partially with steroids. Tapering off corticosteroid dosage resulted in relapse, and complete recovery was only obtained after sotalol was stopped.

Systemic sarcoidosis initially presenting as an orbital tumour

A 73 year old woman presented with redness, itching and painless proptosis of the left eye. Clinical examination and computed tomographic (CT) scan of the orbit revealed a postero-ocular mass, the biopsy of which showed a noncaseating, giant cellular, epithelioid granuloma compatible with sarcoidosis. The patient had no respiratory complaints, but the thoracic CT scan showed multiple bilateral hilar and mediastinal adenopathies. Gallium scan showed increased uptake in both hilar regions, in the left orbit and in the right parotid gland. Multiple bronchial biopsies revealed sarcoid granulomas, with a bronchoalveolar lavage (BAL) cytological pattern of active sarcoidosis. The evolution was favourable with prednisolone given at a dose of 0.5 mg.kg-1 daily. It is suggested that in an unusual presentation of sarcoidosis, a thorough search should be made for localization at other sites, lungs in particular, even in the absence of respiratory complaints.