Digestive outcomes in Cystic fibrosis

[A systemic gene therapy for the treatment of cystic fibrosis]

Le master I2VB se propose de donner les bases conceptuelles et pratiques des différents aspects de l’infectiologie. Il s’appuie sur une coopération exemplaire entre les équipes de recherche en infectiologie et en immunologie de l’Université de Tours, et celles, entre autres, de l’Unité Infectiologie et Santé Publique (ISP) du Centre INRAE de Tours-Nouzilly, concrétisée par une profonde interaction entre chercheurs et enseignants-chercheurs.

Cette formation aborde aussi bien les aspects fondamentaux et appliqués de l’infectiologie et de l’immunologie allant de l’étude moléculaire des interactions entre le pathogène et son hôte, jusqu’à la conception et la mise sur le marché des produits de la vaccinologie, des biothérapies anti-infectieuses et des anticorps immuno-thérapeutiques.

Le master I2VB (niveau M1) donne lieu aux parcours ICM, I&B et AcT (niveau M2).

Cystic fibrosis and fat malabsorption: Pathophysiology of the cystic fibrosis gastrointestinal tract and the impact of highly effective CFTR modulator therapy

Cystic fibrosis (CF) is a progressive, genetic, multi-organ disease affecting the respiratory, digestive, endocrine, and reproductive systems. CF can affect any aspect of the gastrointestinal (GI) tract, including the esophagus, stomach, small intestine, colon, pancreas, liver, and gall bladder. GI pathophysiology associated with CF results from CF membrane conductance regulator (CFTR) dysfunction. The majority of people with CF (pwCF) experience exocrine pancreatic insufficiency resulting in malabsorption of nutrients and malnutrition. Additionally, other factors can cause or worsen fat malabsorption, including the potential for short gut syndrome with a history of meconium ileus, hepatobiliary diseases, and disrupted intraluminal factors, such as inadequate bile salts, abnormal pH, intestinal microbiome changes, and small intestinal bacterial overgrowth. Signs and symptoms associated with fat malabsorption, such as abdominal pain, bloating, malodorous flatus, gastroesophageal reflux, nausea, anorexia, steatorrhea, constipation, and distal intestinal obstruction syndrome, are seen in pwCF despite the use of pancreatic enzyme replacement therapy. Given the association of poor nutrition status with lung function decline and increased mortality, aggressive nutrition support is essential in CF care to optimize growth in children and to achieve and maintain a healthy body mass index in adults. The introduction of highly effective CFTR modulator therapy and other advances in CF care have profoundly changed the course of CF management. However, GI symptoms in some pwCF may persist. The use of current knowledge of the pathophysiology of the CF GI tract as well as appropriate, individualized management of GI symptoms continue to be integral components of care for pwCF.

Gastroenterology services for patients with Cystic Fibrosis across Australia and New Zealand: a multi-stakeholder assessment of patients' and professionals' perspectives

Introduction

Gastrointestinal (GI) symptoms are common in individuals with Cystic Fibrosis (CF). International research has highlighted that GI care for this group of patients is lacking. Gastroenterology services to CF clinics across Australasia are yet to be examined. This study aimed to describe the current service delivery model and identify areas for improvement that may lead to positive patient outcomes.

Materials and methods

CF clinicians (dietitians, clinical nurse consultants, respiratory consultants), gastroenterologists (GE), and patients or their carers from Australia and New Zealand (NZ) were surveyed online to gather their opinions on CF gastroenterology services provided in their region. Data were analysed using descriptive statistics (frequencies and percentages). Likert scale questions were analysed by grouping responses 1-5 and 6-10, presented alongside the median and interquartile range (IQR). Mann-Whitney U and chi-square tests were used to look at differences between stakeholder groups.

Results

One hundred and fifty-six health professionals and 172 patients or their carers completed the survey. Results showed that the current GI model of care is predominantly a publicly funded service delivered outside of CF clinic time. GE are largely not integrated into the CF team and report a lack of training opportunities. There is a higher level of dissatisfaction with the current service model in NZ than Australia.

Discussion

No stakeholder group deemed the current CF gastroenterology service model as adequate, leaving opportunity for transformations in this field. Ideally this study will invigorate the need for promotion and integration of GI services that would ultimately benefit the whole CF community.

The Anion Channel TMEM16a/Ano1 Modulates CFTR Activity, but Does Not Function as an Apical Anion Channel in Colonic Epithelium from Cystic Fibrosis Patients and Healthy Individuals

Studies in human colonic cell lines and murine intestine suggest the presence of a Ca2+-activated anion channel, presumably TMEM16a. Is there a potential for fluid secretion in patients with severe cystic fibrosis transmembrane conductance regulator (CFTR) mutations by activating this alternative pathway? Two-dimensional nondifferentiated colonoid-myofibroblast cocultures resembling transit amplifying/progenitor (TA/PE) cells, as well as differentiated monolayer (DM) cultures resembling near-surface cells, were established from both healthy controls (HLs) and patients with severe functional defects in the CFTR gene (PwCF). F508del mutant and CFTR knockout (null) mice ileal and colonic mucosa was also studied. HL TA/PE monolayers displayed a robust short-circuit current response (ΔIeq) to UTP (100 µM), forskolin (Fsk, 10 µM) and carbachol (CCH, 100 µM), while ΔIeq was much smaller in differentiated monolayers. The selective TMEM16a inhibitor Ani9 (up to 30 µM) did not alter the response to luminal UTP, significantly decreased Fsk-induced ΔIeq, and significantly increased CCH-induced ΔIeq in HL TA/PE colonoid monolayers. The PwCF TA/PE and the PwCF differentiated monolayers displayed negligible agonist-induced ΔIeq, without a significant effect of Ani9. When TMEM16a was localized in intracellular structures, a staining in the apical membrane was not detected. TMEM16a is highly expressed in human colonoid monolayers resembling transit amplifying cells of the colonic cryptal neck zone, from both HL and PwCF. While it may play a role in modulating agonist-induced CFTR-mediated anion currents, it is not localized in the apical membrane, and it has no function as an apical anion channel in cystic fibrosis (CF) and healthy human colonic epithelium.

Treatment Preference Among People With Cystic Fibrosis: The Importance of Reducing Treatment Burden

BACKGROUND

There is a growing consensus that the perspective of the patient should be considered in the evaluation of novel interventions.

RESEARCH QUESTION

What treatment outcomes matter to people with cystic fibrosis (CF), and what trade-offs would they make to realize these outcomes?

STUDY DESIGN AND METHODS

Adults attending a specialist CF center were invited to complete an online discrete choice experiment (DCE). The DCE required participants to evaluate hypothetical CF treatment profiles, defined by impact on lung function, pulmonary exacerbations, abdominal symptoms, life expectancy, quality of life, inhaled medicine usage, and physiotherapy requirement. Choice data were analyzed, using multinomial logit and latent class models.

RESULTS

One hundred and three people with CF completed the survey (median age, 35 years; range, 18-76 years); 52% were female; mean FEV1 % predicted, 69% [SD, 22%]). On average, an improvement in life expectancy by 10 years or more had the greatest impact on treatment preference, followed by a 15% increase in lung function. However, it was shown that people would trade substantial reductions in these key outcomes to reduce treatment time or burden. Preference profiles were not uniform across the sample: three distinct subgroups were identified, each placing markedly different importance on the relative importance of both life expectancy and lung function compared with other attributes.

INTERPRETATION

The relative importance of treatment burden to people with CF, compared with life expectancy and lung function, suggests it should be routinely captured in clinical trials as an important secondary outcome measure. When considering the patient perspective, it is important that decision-makers recognize that the values of people with CF are not homogeneous.

In vivo correction of cystic fibrosis mediated by PNA nanoparticles

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. We sought to correct the multiple organ dysfunction of the F508del CF-causing mutation using systemic delivery of peptide nucleic acid gene editing technology mediated by biocompatible polymeric nanoparticles. We confirmed phenotypic and genotypic modification in vitro in primary nasal epithelial cells from F508del mice grown at air-liquid interface and in vivo in F508del mice following intravenous delivery. In vivo treatment resulted in a partial gain of CFTR function in epithelia as measured by in situ potential differences and Ussing chamber assays and correction of CFTR in both airway and GI tissues with no off-target effects above background. Our studies demonstrate that systemic gene editing is possible, and more specifically that intravenous delivery of PNA NPs designed to correct CF-causing mutations is a viable option to ameliorate CF in multiple affected organs.

Meconium Peritonitis, Intestinal Atresia Combined With Biliary Atresia: A Case Report

Meconium peritonitis (MP) combined with intestinal atresia (IA) is a rare neonatal condition, and it is even rarer in combination with biliary atresia (BA). We describe a case of an infant who developed short bowel syndrome after partial intestinal resection due to MP and IA, along with a Santullienterostomy. During continuous enteral and parenteral nutrition, the stool color became paler. BA was identified by elevated direct bilirubin (DBIL), gamma-glutamyltransferase (GGT), serum matrix metalloproteinase-7 (MMP-7), and hepatobiliary ultrasound; then, Kasai portoenterostomy (KPE) was performed promptly. The Roux-en-Y limb was adjusted intraoperatively to preserve the maximum length of the small intestine while closing the enterostomy. After the operation, the infant gradually adapted to enteral nutrition, his bilirubin level returned to normal, and his weight gradually caught up to the normal range. Although rare, BA should be suspected when MP is combined with IA and when the stool becomes paler in color in the enterostomy state.