Resonance vibration interventions in the femur: Experimental-numerical modelling approaches

MOTIVE

External vibration excitation might be key to many novel non-surgical interventions for pathologies in the musculoskeletal system and in other parts of the human organism. Lack of understanding about vibration patterns, their controllability, and reproducibility are three limitations of ongoing research. This study establishes a bovine vibration model and animal model replacements for future research.

METHODS

We used biological samples (n=5) and one polyurethane sample of the bovine femur. Mechanical resonance was measured experimentally and analysed numerically by finite element method.

MAIN RESULTS

The experiments obtained 5 distinct mode shapes for the biological sample set, with standard deviation < 7.5%. Finite element analysis of the biological samples can replicate experimental mode shape deflection. The use of polyurethane changes resonance character but results are also good approximations of the biological samples.

CONCLUSIONS

A model of the bovine femur with consistent resonance behaviour is presented with alternatives (polyurethane and finite element analysis) that can serve in reducing the number of necessary biological samples. Future work will be to adapt results to human anatomy. Of clinical interest will be to influence bone pathologies such as post-surgical non-union, or bone functionality as part of haematopoiesis and endocrine secretion.

Immunocompetent Human Intestinal Models in Preclinical Drug Development

The intestinal epithelial barrier, together with the microbiome and local immune system, is a critical component that maintains intestinal homeostasis. Dysfunction may lead to chronic inflammation, as observed in inflammatory bowel diseases. Animal models have historically been used in preclinical research to identify and validate new drug targets in intestinal inflammatory diseases. Yet, limitations about their biological relevance to humans and advances in tissue engineering have forced the development of more complex three-dimensional reconstructed intestinal epithelium. By introducing immune and commensal microbial cells, these models more accurately mimic the gut's physiology and the pathophysiological changes occurring in vivo in the inflamed intestine. Specific advantages and limitations of two-dimensional (2D) and three-dimensional (3D) intestinal models such as coculture systems, organoids, and microfluidic devices to study inflammatory and immune-related responses are highlighted. While current cell culture models lack the cellular and molecular complexity observed in vivo, the emphasis is put on how these models can be used to improve preclinical drug development for inflammatory diseases of the intestine.