# Application of Endogenous Stem Cells in the Repair of Annulus Fibrosus Injury of Intervertebral Discs

## TL;DR

This paper explores how stem cells might help repair damaged spinal discs, which cause chronic back pain, and discusses challenges and future directions for this approach.

## Contribution

The paper reviews the potential of endogenous stem cells for intervertebral disc repair and identifies barriers to clinical translation.

## Key findings

- Endogenous stem cells can synthesize extracellular matrix and reduce inflammation in disc repair.
- Preclinical studies show MSCs and iPSCs can restore disc hydration and reduce pain.
- Clinical trials report partial success but face challenges like hostile disc environments.

## Abstract

Intervertebral disc degeneration (IVDD), a major contributor to chronic low back pain (LBP), involves progressive extracellular matrix (ECM) degradation and limited self-repair. Current therapies alleviate symptoms but fail to halt degeneration, driving interest in endogenous stem cell-based regeneration. Endogenous stem/progenitor cells within disc niches exhibit regenerative potential through ECM synthesis, anti-inflammatory signaling, and exosomal miRNA-mediated repair. Preclinical studies highlight mesenchymal stem cell (MSC) transplantation and reprogramed induced pluripotent stem cells (iPSCs) in restoring disc hydration and reducing pain, while early clinical trials report symptomatic relief (e.g., 70% pain reduction) but incomplete structural recovery. Challenges include the disc's hostile microenvironment (hypoxia and nutrient deprivation), age-related depletion of endogenous stem/progenitor cells, and impaired cell homing under mechanical stress. Emerging strategies target epigenetic modulation, biomimetic scaffolds, and combination therapies to enhance cell survival and integration. Despite promising preclinical outcomes, clinical translation requires overcoming microenvironmental barriers and refining delivery systems. Future efforts should prioritize large-animal validation and biomarker-guided approaches to bridge the gap between experimental success and therapeutic application.