Synovial biopsies in clinical practice and research: current developments and perspectives

Abstract

Synovial biopsy techniques have developed and widely expanded over the past few years, in particular due to the development of ultrasound-guided procedures. This article reviews the different techniques, clinical applications, and the latest advances in translational research as well as current challenges and perspectives. The first part focuses on different techniques available for biopsy, along with their feasibility, success rate, tolerance, and training requirements. In the second part, clinical applications are described. Data on diagnostic performances are reported, especially regarding septic arthritis. Translational research applications are described and explained in the final part, from the early histological studies and the first description of pathotype to more recent technologies involving -omics. Latest developments involving single-cell RNA sequence analysis have allowed the discovery of new cell subpopulations with remarkable roles in RA pathophysiology. These studies pave the ground for the discovery of new therapeutic targets and the implementation of personalized therapy in RA. Key Point•This review provides an overview of synovial biopsy techinques and applications especially in clinical and translational research.

Inside the Joint of Inflammatory Arthritis Patients: Handling and Processing of Synovial Tissue Biopsies for High Throughput Analysis

“…Several mechanisms including metabolic changes, hypoxia, cytokines, growth factors and immune-stromal cell crosstalk are involved in synovial inflammation; for instance, the hypoxic conditions of the synovial joint drives hypoxia-inducible factor 1-alpha (HIF-1α)-induced glycolysis in some of the mutual crosstalk between synovial fibroblast and immune cells, has been shown to evolve with the disease progression, suggesting that synovial fibroblasts have transitional properties in RA ( 59 ). Therefore, the joint is a very dynamic environment and a more in-depth characterization of immune and stromal cells at the site of inflammation, is required to elucidate disease pathogenesis and progression ( 1 , 35 , 54 , 62 , 63 ). Isolation of single cells suspension from the synovium by cell sorting, CyTOF, spatial transcriptomic and advanced imaging technology of synovial tissue will aid in improving our understanding of synovial cell crosstalk, activation, and disease progression.…”

Will rheumatologists ever pick up the arthroscope again?

“…192 While blind, closed synovial biopsy has been possible since the '50s, the procedure never was widely applied. 193 Ultrasound-guided synovial biopsy has become very popular, drawing in many former rheumatologist-arthroscopists. Access is possible in a clinic room, and no operating room politics are involved.…”

EULAR points to consider for minimal reporting requirements in synovial tissue research in rheumatology

“…ST analysis may also advance understanding of disease pathophysiological mechanisms and permit identification of potential therapeutic targets. [1][2][3] Moreover, new developments in single cell methodologies are driving innovation and demand for ST-based studies. [4][5][6] Methods to obtain ST, namely synovial biopsy (SB) procedures, are becoming more acceptable to patients and have been performed with increasing frequency over recent years for both clinical and translational research purposes.…”

“…Analyses of synovial tissue (ST) at both cellular and molecular levels offer a promising approach for personalised therapy in rheumatic diseases. ST analysis may also advance understanding of disease pathophysiological mechanisms and permit identification of potential therapeutic targets 1–3. Moreover, new developments in single cell methodologies are driving innovation and demand for ST-based studies 4–6.…”