From Biopsy to Bench: A PI’s Guide to Reproducible ICM with the EasyMount P2400

A new Polish pilot study shows how to run intestinal current measurement (ICM) in rectal biopsies using the EasyMount® Low-Volume Ussing System P2400 and P2407B slider, offering a blueprint PIs can follow to generate high-fidelity CFTR readouts across CF, CRMS/CFSPID, and healthy cohorts. Link to article: https://www.mdpi.com/2077-0383/14/17/6020

Key takeaways (for lab leads):

• The authors implemented ECFS DNWG SOP v2.7 and explicitly reported the EasyMount P2400 + P2407B hardware—excellent for method reproducibility and equipment transparency.

• Their workflow pinned down tight handling windows: 10–20 min from biopsy to mounting; pre-incubation at 37 °C, viability threshold Rt > 10 Ω·cm²; and a defined stimulant sequence (amiloride → IBMX/forskolin → carbachol → genistein → DIDS → histamine).

• Cumulative ΔIsc after carbachol + IBMX/forskolin + histamine clearly separated CF from CRMS/CFSPID and healthy controls, supporting ICM’s diagnostic value when sweat chloride is equivocal.

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The reproducible ICM blueprint (directly traceable to the paper)

Hardware & environment

• Chamber: EasyMount Low-Volume Ussing System P2400 (Physiologic Instruments)

• Slider: P2407B (for small rectal biopsies)

• Temperature: pre-incubate chambers at 37 °C

• Voltage clamp: measure PD, Isc, and Rt per SOP v2.7 

Sample handling & timing

• Rectal biopsy collection: ≥3–4 fragments per subject with 2.3 mm disposable forceps

• Transport: immediately into ice-cold PBS

• Mounting window: 10–20 min from biopsy start to experiment start

• Baseline: after ~5 min pre-incubation, record PD_basal, Isc_basal, Rt_basal

• Viability: include responses only if tissue is intact and Rt > 10 Ω·cm² 

Stimulus sequence (mucosal/serosal as specified)

• Amiloride (100 µM) → IBMX (10 µM) + forskolin (100 µM) → carbachol (100 µM) → genistein (50 µM) → DIDS (200 µM) → histamine (500 µM)

• Compute cumulative secretion (e.g., carbachol + IBMX/forskolin + histamine) for group comparisons. 

Results the setup can resolve

• Cumulative ΔIsc (carbachol + IBMX/forskolin + histamine):

  • CF: 15.32 ± 15.47 µA/cm²

  • CRMS/CFSPID: 86.84 ± 37.84 µA/cm² (p < 0.001 vs CF)

  • Healthy controls: 80.16 ± 48.54 µA/cm² (p = 0.005 vs CF)
    → Practical implication: power future studies around cumulative responses; these combinations are highly discriminative for CF vs non-CF.

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Equipment transparency (and where to find it)

The study explicitly names the EasyMount P2400 Ussing system and P2407B slider. For labs building capacity, this low-volume architecture helps conserve reagents and stabilizes small tissues—advantages when working with pediatric biopsies or high-cost modulators. 

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Implementation notes for new ICM programs

• Adopt ECFS DNWG SOP v2.7 and stick to the paper’s timing windows; both are critical for reproducibility across sites.

• Standardize viability thresholds (e.g., Rt > 10 Ω·cm²) and reject runs that miss QC—this was essential to the authors’ dataset quality.

• Report make/model of chambers and sliders in the Methods—this paper sets a high bar for equipment disclosure and enables meta-analyses downstream.

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Full credit to the authors

Postek M., Zybert K., Wozniacki L., Woynarowski M., Sands D. Pilot Evaluation of Intestinal Current Measurement in Cystic Fibrosis and CRMS/CFSPID Patients in Poland. Journal of Clinical Medicine. 2025;14(17):6020. Published: Aug 26, 2025. DOI: 10.3390/jcm14176020. We thank the team at the Cystic Fibrosis Center in Dziekanów Leśny for openly detailing their protocol and hardware choices. MDPI