Extracellular vesicle and soluble fractions of adipose tissue-derived mesenchymal stem cells secretome induce inflammatory cytokines modulation in an in vitro model of discogenic pain.

BACKGROUND CONTEXT: Mesenchymal stem cells (MSCs) secretome or conditioned medium (CM) is a complex cocktail of different molecules, some of which, particularly those contained in extracellular vesicles, already have proven therapeutic applications. PURPOSE: CM may well represent promising therapy for discogenic pain and the intention of this work is to assess its therapeutic potential using an in vitro model of this condition. STUDY DESIGN: This is an experimental study. METHODS: Our in vitro model comprised nucleus pulposus (NP) and annulus fibrosus (AF) cells inflamed with TNF. To assess the potential therapeutic value of CM and its components, extracellular vesicles (EVs) and soluble culture fraction (SF), cell inflammation took place under 3 different conditions: either in the presence of whole CM, isolated EVs or SF, and concentrations of pro-inflammatory cytokines, metalloproteinases (MMPs) and neurotrophic factors produced in all 3 cases were compared. RESULTS: In the presence of whole CM, both in vitro gene expression by the NP and AF test cells and analysis of their protein content showed high modulatory effects on inflammation and MMP inhibition. The presence of EVs and SF showed similar but much smaller effects, and this was particularly marked in the case of NP cells. CONCLUSIONS: Our results show that, compared to EVs and SF, the presence of whole CM has the greatest positive effect on the modulation of pro-inflammatory and catabolic factors. These observations suggest that CM could protect against inflammation and the resulting intervertebral disc (IVD) degeneration that leads to discogenic pain. CLINICAL SIGNIFICANCE: Many patients' expectations are not met by current non-operative and surgical treatments for discogenic low back pain. We propose the use of the MSCs secretome for assessing its potential as cell-free therapy to treat degenerative disc disease modulating the inflammatory response.

Assessment of regeneration in meniscal lesions by use of mesenchymal stem cells derived from equine bone marrow and adipose tissue.

OBJECTIVE To assess the ability to regenerate an equine meniscus by use of a collagen repair patch (scaffold) seeded with mesenchymal stem cells (MSCs) derived from bone marrow (BM) or adipose tissue (AT). SAMPLE 6 female Hispano-Breton horses between 4 and 7 years of age; MSCs from BM and AT were obtained for the in vitro experiment, and the horses were subsequently used for the in vivo experiment. PROCEDURES Similarities and differences between MSCs derived from BM or AT were investigated in vitro by use of cell culture. In vivo assessment involved use of a meniscus defect and implantation on a scaffold. Horses were allocated into 2 groups. In one group, defects in the medial meniscus were treated with MSCs derived from BM, whereas in the other group, defects were treated with MSCs derived from AT. Defects were created in the contralateral stifle joint but were not treated (control samples). RESULTS Both types of MSCs had universal stem cell characteristics. For in vivo testing, at 12 months after treatment, treated defects were regenerated with fibrocartilaginous tissue, whereas untreated defects were partially repaired or not repaired. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that MSCs derived from AT could be a good alternative to MSCs derived from BM for use in regenerative treatments. Results also were promising for a stem cell-based implant for use in regeneration in meniscal lesions. IMPACT FOR HUMAN MEDICINE Because of similarities in joint disease between horses and humans, these results could have applications in humans.

Validating the probe-to-bone test and other tests for diagnosing chronic osteomyelitis in the diabetic foot.

OBJECTIVE: To compare the diagnostic characteristics of tests used for a prompt diagnosis of chronic osteomyelitis in the diabetic foot, using bone histology as the criterion standard. The tests assessed were probe-to-bone (PTB), clinical signs of infection, radiography signs of osteomyelitis, and ulcer specimen culture. RESEARCH DESIGN AND METHODS: A prospective study was performed on patients with foot ulcers referred to our diabetic foot clinic. Ulcer infection was diagnosed by recording clinical signs of infection and taking specimens for culture. The presumptive diagnosis of osteomyelitis was based on these results and the findings of a plain X-ray and PTB test. All patients with a clinical suspicion of bone infection were subjected to surgical treatment of the affected bone. During surgery, bone specimens were obtained for a histological diagnosis of osteomyelitis. RESULTS: Over 2.5 years, 210 foot lesions were consecutively examined and 132 of these wounds with clinical suspicion of infection selected as the study sample. Of these, 105 (79.5%) lesions were diagnosed as osteomyelitis. Among the tests compared, the best results were yielded by the PTB test including an efficiency of 94%, sensitivity of 98%, specificity of 78%, positive predictive value of 95%, and negative predictive value of 91% (P < 0.001, κ 0.803); the positive likelihood ratio was 4.41, and the negative likelihood ratio was 0.02 (95% CI). CONCLUSIONS: In our outpatient population with a high prevalence of osteomyelitis, the PTB test was of greatest diagnostic value, especially for neuropathic ulcers, and proved to be efficient for detecting osteomyelitis in the diabetic foot.