Characterization and induction of human pre-adipocytes.

Human processed lipoaspirate is a source of multipotent adult stem cells that are able to differentiate between mesenchymal and neurogenic lineage. We characterized PLA cells by cytometry and then they were cultured to induce differentiation into myogenic and neurogenic lineage. Lipoaspirates were digested with collagenase to obtain the pellet, which was labelled with anti-CD44, anti-CD45, and anti-CD90. We used BD FACS Calibur flow cytometer to acquire cellular events. Some cells were cultured at 37 degrees C and 5% CO(2) in neurogenic or myogenic medium and analysed by immunocytochemistry, using Neuron specific enolase, Vimentin, Glial fibrillary acidic protein, Tau, MAP2 to confirm neurogenic differentiation, MyoD1, Myosin heavy chain, Actin smooth muscle, vimentin to confirm myogenic differentiation. The cytometry results suggest that a part of the cells are of a mesenchymal origin, among which there are progenitor endothelial cells and leucocytes. Microscopy observation already reveals neuronal morphology and longitudinal multinucleated cells compared to control cells. Neurogenic cells only express NSE (early neuronal progenitor marker), but not GFAP, Tau, MAP2 (mature neuron and glial markers); myogenic cells are positive for MyoD1 and Myosin heavy chain. This demonstrates that lipoaspirate cells are capable of differentiating in vitro over a short period of time, and could be employed in biological and clinical research, like mesenchymal adult stem cells.

Characterization of multipotent cells from human adult hair follicles.

Recent works demonstrated the presence of a multipotent epithelial cell population in the bulge region of adult human hair follicles. These cells can be cultured in vitro, thus leading to the preparation of dermal-epidermal substitutes which are applicable in the treatment of burns and ulcers. We evaluated the main marker expression in cells obtained from stripped human hair follicles. A pool of hair follicles were incubated at 37 degrees C and 5% CO(2) in a growth medium. The cells were then labelled with antibodies (anti-CD34, anti-CD38, anti-CD45, anti-CD90, anti-CD133, anti-CD146) and analysed by cytometry. We also used hair follicles for immunohistochemical studies, employing antibodies such as CD34, Actin Smooth Muscle, Filaggrin, Desmin, Vimentin, Glial Fibrillary Acidic Protein, Ki-67, PanCytokeratin, CK15, CK19. The cytometry results revealed that a part of bulge cells were CD34+ (1-2%). CD34+ population comprises both large, CD45-, CD133-, CD146- cells and small, CD45+, CD133+, CD146+ cells. Thus, a part of CD34+ cells present a mature endothelial marker (CD146). An expression of the proliferation marker Ki-67 and the stem cell marker CD34 is present in the follicle bulge region. In conclusion, we observed that the stripped hair follicle has the same multipotent cell population as adult and fetal scalp hair follicles.

Replacement of the medial collateral ligament with polypropylene mesh or a polyester suture in dogs.

The medial collateral ligament of one stifle in 20 adult dogs was excised and replaced with polypropylene mesh or a polyester suture. After 26 weeks, the fibrous tissue-prosthesis composites were evaluated clinically, morphologically, and biomechanically. Clinical lameness was not significantly different after 10 days. The polypropylene mesh reconstructions consistently had more fibrous tissue and greater collagenous ingrowth than the polyester suture reconstructions. There were four complications related to fixation of the polypropylene mesh prosthesis and one to the polyester suture. The polypropylene mesh reconstructions had greater stability and were biomechanically more similar to the natural ligaments than the polyester suture reconstructions. Although the results with polypropylene mesh were favorable, more challenging biomechanical testing and alternative anchoring techniques are required before polypropylene mesh can be recommended as a collateral ligament replacement in dogs.

Delayed and nonunion fractures.

Failures in bone healing can result from technical problems, biologic failures, or a combination of the two. Inadequate stabilization of bone fragments against the effects of rotational forces is a common cause of nonunion. Early identification of a pseudoarthrosis can be difficult; the diagnosis is usually delayed, thus the morbidity associated with this disorder is significant. Often, the nonunion is complicated by atrophy of surrounding soft tissues, muscle contracture, and stiff joints. The goals in the treatment of the nonunion are to identify and correct the underlying causes, with the primary objective being the return of function. The type of treatment depends on the classification of the pseudarthrosis, including the condition of the surrounding soft tissues, blood supply, and viability of the nonunion, location, and presence or absence of infection.