Rectal organoid morphology analysis (ROMA) as a promising diagnostic tool in cystic fibrosis

Cuyx, Senne; Ramalho, A.S.; Corthout, Nikky; Fieuws, Steffen; Fürstová, Eva; Arnauts, Kaline; Ferrante, Marc; Verfaillie, Cathérine; Munck, Sebastian; Boon, Mieke; Proesmans, Marijke; Dupont, Lieven; Boeck, K. De; Vermeulen, François

doi:10.1136/thoraxjnl-2020-216368

Cited by 26 publications

(17 citation statements)

References 9 publications

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“…Nevertheless, in light of its previous modulator refractoriness, questions about G85E's underlying molecular defects remain. The FIS assay performed in patient-derived rectal organoids is a robust and well-validated preclinical model for phenotyping and drug testing [ 17 , 19 , 34 ], a procedure called theratyping [ 16 ]. We have used patient-derived rectal organoids to test the latest approved CFTR modulator, elexacaftor, as well as combinations of known types of correctors (I/II/III) and potentiators (I/II) with distinct mechanisms of action for previously drug-refractory mutants G85E and N1303K.…”

Section: Discussionmentioning

confidence: 99%

Novel CFTR modulator combinations maximise rescue of G85E and N1303K in rectal organoids

et al. 2022

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IntroductionCystic fibrosis (CF) is a severe monogenic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Several types of CFTR modulators (correctors/potentiators) have been developed to overcome protein dysfunction associated with these mutations. CFTR modulator therapy is now available for the major CF-causing mutations, however 10% of people with CF remain without causal treatments. By combining investigational and market approved CFTR modulators, we aimed to maximise functional rescue of iva-, luma- and tezacaftor refractory mutants G85E and N1303K.MethodsWe used the well-established forskolin induced swelling (FIS) in primary rectal organoids to assess responses to different CFTR corrector and potentiator types. The FIS analysis was performed with brightfield microscopy, allowing both 1 h and 24 h follow-up. Corrector and potentiator activity of elexacaftor was investigated.ResultsFor G85E, maximal rescue was observed by a combination of elexacaftor and corr4a. For N1303K, the quadruple combination teza-elexa-ivacaftor with apigenin was required to obtain a rescue similar to that of luma-ivacaftor rescued F508del. Elexacaftor rescued G85E and N1303K by different mechanisms, with chronic corrector effects on G85E and acute potentiation of N1303K only in the presence of ivacaftor. Synergy in N1303K rescue for iva-elexacaftor and apigenin suggests at least three potentiator mechanisms for this mutant. 24 h FIS identified ivacaftor as the main CFTR modulator for N1303K and elexacaftor and apigenin as co-potentiators.ConclusionsNovel combinations of CFTR modulators can further improve functional rescue of G85E and N1303K in rectal organoids, although for N1303K more effective CFTR modulators are still needed.

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Section: Discussionmentioning

confidence: 99%

Novel CFTR modulator combinations maximise rescue of G85E and N1303K in rectal organoids

et al. 2022

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“…The morphological difference between WT (pre-swollen) and CF organoids ( Cuyx et al., 2021 ), means comparing CFTR activity between CF and healthy CFTR function by FIS assay cannot be achieved ( Dekkers et al., 2016a ; van Mourik et al., 2019 ). In order to compare I37R/F508del to wild-type CFTR activity, organoid-derived monolayers were created ( Figure 1 G) and CFTR ion transport was performed ( Zomer-van Ommen et al., 2018 ).…”

Section: Resultsmentioning

confidence: 99%

Molecular dynamics and functional characterization of I37R-CFTR lasso mutation provide insights into channel gating activity

et al. 2022

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“…We chose to include the classification "CF diagnosis not resolvedneed further testing" among the diagnostic options for two reasons: a) this is a terminal "node" in the current CFF diagnostic decision tree, and b) the decision to proceed to further testing in such cases is not inconsequential, resulting in costs incurred for either gene sequencing, NPD, ICM or other functional CFTR assays such as nasal epithelial cell-derived spheroid testing or rectal organoid morphology analysis. [31,32] Exploring the proportion of respondents who feel further testing is warranted in cases such as these is informative and helps gauge the appetite for this approach among practicing clinicians. Indeed, in our study, 23.1% of case assessments resulted in a recommendation to advance to further testing and the proportion of respondents choosing this option was higher in the UK/Ireland compared to Canada which may reflect differences in local practice or access to specialized testing.…”

Section: Discussionmentioning

confidence: 99%

Diagnostic agreement among experts assessing adults presenting with possible cystic fibrosis: need for improvement and implications for patient care

et al. 2022

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BackgroundIncreasing awareness of milder presentations of cystic fibrosis (CF) and greater interest in non-CF bronchiectasis is likely to lead to more CF screening by respiratory clinicians. As a result, adults who may not strictly fulfil CF diagnostic criteria, yet display evidence of abnormal cystic fibrosis transmembrane conductance regulator (CFTR) function are being identified. The degree of agreement on diagnosis and care needs in these cases between CF-clinicians remains unknown, and has implications for patient care, including access to CFTR-modulator therapies.MethodsWe surveyed adult-CF physicians in Canada, the USA, the UK, and Ireland, and presented them with anonymised vignettes of adult patients referred for assessment of possible CF. Diagnostic inter-rater agreement over diagnosis, ease of classifying cases and appropriate follow-up was assessed using Krippendorf's alpha statistic.ResultsAgreement over diagnosis (alpha=0.282), ease of classification (alpha=-0.01) and recommended follow-up (alpha=0.054) was weak. Clinician experience (>10 years and 5–10 years versus <5 years) and location (UK/Ireland versus Canada) were associated with higher odds of recommending further testing compared to selecting a formal diagnosis (OR 2.87, p=0.022, OR 3.74; p=0.013; and OR 3.16, p=0.007, respectively). A modified standard of care was recommended in 28.7% of cases labelled as CF. 70% of respondents agreed with the statement that “distinction between CF and CFTR-RD has become significantly more pertinent with the advent of highly effective CFTR-modulators”.InterpretationOur results demonstrate low diagnostic concordance among CF specialists assessing cases of possible adult CF and highlights an area in need of improvement.

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Rectal organoid morphology analysis (ROMA) as a promising diagnostic tool in cystic fibrosis

Cited by 26 publications

References 9 publications

Novel CFTR modulator combinations maximise rescue of G85E and N1303K in rectal organoids

Novel CFTR modulator combinations maximise rescue of G85E and N1303K in rectal organoids

Molecular dynamics and functional characterization of I37R-CFTR lasso mutation provide insights into channel gating activity

Diagnostic agreement among experts assessing adults presenting with possible cystic fibrosis: need for improvement and implications for patient care

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