Human adult periodontal ligament-derived cells integrate and differentiate after implantation into the adult mammalian brain.

Previous studies suggest that neural crest (NC)-derived stem cells may reside in NC derivatives including the human periodontal ligament (hPDL). The isolation and manipulation of autologous NC-derived cells could be an accessible source of adult neural stem cells for their use in cell replacement and gene transfer to the diseased central nervous system. In this study, we examined the expression of NC markers and neural differentiation potential of hPDL-derived cells both in vitro and in vivo. In vitro we found that hPDL-derived cells expressed stem cell markers (Oct3/4, Nestin, Sox2, and Musashi-1) and a subset of NC cell markers (Slug, p75(NTR), Twist, and Sox9). hPDL-derived cells differentiated into neural-like cells based on cellular morphology and neural marker expression (TUJ1, MAP2, MAP1b, GAD65/67, GABA, NeuN, ChAT, GAT1, synaptophysin, GFAP, NG2, and O4). In vivo, hPDL-derived cells survive, migrate, and give rise to DCX(+), NF-M(+), GABA(+), GFAP(+), and NG2(+) cells after grafting the adult mouse brain. Some of the grafted hPDL-derived cells were located in stem cell niches such as the ventricular epithelium and the subventricular zone of the anterolateral ventricle wall as well as in the subgranular zone of the hippocampal dentate gyrus. Thus, the hPDL contains stem cells that originate from the NC and can differentiate into neural cells. The engraftment and differentiation properties of hPDL-derived cells in the adult brain indicate that they are a potential stem cell source to be used in neuroregenerative and/or neurotrophic medicine.

Results following repair of gluteus medius defects following total hip arthroplasty.

13 patients with tears in the gluteus medius tendon following total hip arthroplasty were studied. The diagnosis of a gluteal tear was made on the basis of clinical signs and a positive arthrogram of the hip in all cases. 11 patients underwent gluteus medius repair and two patients declined surgery. 10 patients attended a review clinic (eight gluteal repair patients and two conservatively managed patients) and three were reviewed by telephone and medical notes. The mean follow up was 61 months (range 12-116 months). The mean age at follow up was 71.42 years (69-79 years) and the male to female ratio was 5:8. The mean duration of symptoms prior to repair was 16 months. An anterolateral transgluteal approach had been used for primary surgery in nine cases and in four cases the original surgical approach was unknown. The mean Harris Hip score prior to repair was 77.4 (range 55-87), which improved to a mean post operative Harris hip score of 86.97 (range 79-96) following repair. The Oxford hip score prior to repair was 20 (range 16-25) which improved to a mean of 14.2 after repair (range 4-29). 9 out of 11 patients who had the repair were satisfied and would recommend the procedure. We believe an accurate and timely diagnosis together with repair can reduce the morbidity associated with this post-operative complication following THA.