Table 1.

Summary of clinical research exploring the potential of MSC therapy in human trials

Study	Study design	Patient population	Methods	Results
Yoshikawa et al. [39] 2010	Case reports	Two women aged 70 and 67 years with lumbago and leg pain	Percutaneous injection of autologous BM-MSCs into IVD; Two-years follow-up	Improvement on MRI, higher signal intensity of IVD, alleviation of symptoms
Orozco et al. [40] 2011	Clinical trial	Ten patients with chronic back pain; Average age: 35 years (range 28–42); Four males and six females	Percutaneous injection of expanded autologous BM-MSCs into the nucleus pulposus; One-year follow-up	Improvement of pain and disability (85% of maximum in three months), disc height not recovered radiologically, water content significantly elevated
Pettine et al. [41] 2015	Clinical trial	26 patients; Median age: 40 years (range 18–61); 11 males and 15 females	Autologous bone marrow concentrate disc injection; One-year follow-up	Pain reduction of 33.7% in patients older than 40 years, 69.5% pain reduction of other patients
Centeno et al. [42] 2017	Clinical trial	33 patients with chronic back pain; Median age: 40.3 years (range 19–72); 21 males and 12 females	Injection of culture-expanded, autologous BM-MSCs into IVD; Six-years follow-up	Mean pain improvement of 60% at three years post-treatment, 85% had a reduction in disc bulge size on control MRI
Elabd et al. [43] 2016	Case reports	Five patients with degenerative disc disease; Age range: 25–53 years; Two females and three males	Intradiscal injection of autologous, hypoxic cultured BM-MSCs; Four-to six-years follow-up	Overall improvement in all patients, improvement of strength, 4/5 reported improvement in mobility
Noriega et al. [44] 2017	Randomized-controlled trial	24 patients with chronic back pain randomized into test and control group; Mean age: 38 years; 17 males and seven females	Intradiscal injection of allogeneic BM-MSCs for test group; sham infiltration of paravertebral musculature with anesthetic for control group; One-year follow-up	MSC-treated groups showed quick and significant improvement vs controls, degeneration improved in MSC-treated patients and worsened in controls
Amirdelfan et al. [45] 2020	Multicenter randomized-controlled trial	100 patients with chronic back pain randomized into two test and two control groups in 3:3:2:2 ratio; 53 males and 47 females	Intradiscal injection of allogeneic BM-MSC and BM-MSC with HA for test groups; Intradiscal injection of saline and HA alone for control groups; Three-years follow-up	Significant differences between control and MSC groups regarding pain symptoms and disability index

BM-MSCs: Bone marrow-derived mesenchymal stem cells; IVD: Intervertebral disc; MRI: Magnetic resonance imaging; HA: Hyaluronic acid.