Impact of the chronic wound microenvironment and marine omega-3 fatty acids on skin cell regeneration processes.

Marine long-chain omega-3 polyunsaturated fatty acids (ω3 FA) are involved in numerous cell responses and therefore vital for the mammal organism. Because of the attribution of immunomodulatory effects, a favourable impact on the inflammatory response in chronic wounds and cells involved in wound healing can be suspected. In the experimental setup, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were investigated regarding their impact on metabolic activity, cell proliferation and migration of human keratinocytes (HaCaT) and newborn foreskin fibroblasts (CRL-2522). For simulation of the microenvironment of a chronic wound, human chronic wound fluid (CWF) was used in the experimental setup addressing the in vitro influence of DHA, EPA and CWF on regenerative processes. The results showed a significant increase in the metabolic activity of keratinocytes and fibroblasts after 72 h treatment with DHA and EPA. In contrast, treatment with ω3 FA had no significant positive effect on skin cell proliferation. Both ω3 FA had no influence on in vitro wound closure. CWF demonstrated significantly adverse effects, which ω3 FA were unable to mitigate. It can be concluded that CWF exhibited the expected adverse effect on both skin cell types, especially inhibiting in vitro wound closure. ω3 FAs showed a slightly positive, yet rarely significant effect on human skin cells. Overall, the addition of DHA or EPA showed no relevant benefit for skin cells challenged with human CWF, merely in combination with DHA an initial significant increase in cell metabolism (fibroblasts) and cell proliferation (keratinocytes) could be observed.

Influence of platelet-rich plasma on chondrogenic differentiation and proliferation of chondrocytes and mesenchymal stem cells.

BACKGROUND/AIMS: Autologous chondrocyte (CC) transplantation has the disadvantages of requiring two surgical interventions and in vitro expansion of cells, implying the risk of cellular dedifferentiation. Our clinical aim is to develop a one-step procedure for autologous CC transplantation, i.e. harvesting, isolation and reimplantation of CC performed in one single surgical procedure. Platelet-rich plasma (PRP) is a source of autologous growth factors reported to have mitogenic effects. The objective of this study was to test the influence of PRP as an autologous scaffold on freshly isolated CC and mesenchymal stem cells (MSC). METHODS: CC and MSC were subjected to two- or three-dimensional (3D) growth systems, either with or without PRP. Chondrogenic differentiation was determined via quantification of collagen type II mRNA and immunohistochemical staining. RESULTS: We observed a proliferative effect for MSCs exposed to PRP in monolayer culture and an increase in the expression of chondrogenic markers when cells are exposed to a 3D environment. CCs exposed to PRP show a decrease in the chondrogenic phenotype with increasing proliferative activity. CONCLUSION: PRP has a proliferative effect on CCs and MSCs. In a one-step procedure for autologous CC transplantation, this might be an advantage over other scaffold materials, but confirmation in in vivo studies is required.

[A minimally invasive dorsal approach to the medial femoral condyle as a donor site for osteochondral transfer procedures]. / Entnahme osteochondraler Zylinder aus der medialen dorsalen Femurkondyle über einen minimalinvasiven Zugang.

OBJECTIVE: Long-lasting reconstruction of joint surface by using an osteochondral transfer procedure (OCT). Reduction of donor site morbidity by using a minimally invasive approach to the dorsal medial femoral condyle. INDICATIONS: Grade 3 and 4 cartilage lesions (according to ICRS [International Cartilage Repair Society]), osteochondral lesions, and osteochondrosis dissecans. CONTRAINDICATIONS: Grade 2 or higher-graded cartilage lesions at the dorsal medial femoral condyle, infection, axis deviation of more than 5 degrees in the frontal plane, advanced osteoarthritis. SURGICAL TECHNIQUE: Cylinders at recipient site are removed first, thereby determining number and diameter of donor cylinders. Supine position, skin incision over the dorsal medial femoral condyle. After dissection of soft tissue and superficial fascia, semitendinosus tendon and medial gastrocnemius muscle are retracted to the lateral side, followed by arthrotomy, introduction of two Hohmann retractors medial and lateral of the condyle, and harvesting of the donor cylinders with a tubular chisel. Advantages of the described approach: reduction of soft-tissue trauma, easy surgical technique, additional donor site area besides femoral trochlea and intercondylar notch. POSTOPERATIVE MANAGEMENT: Partial weight bearing of 10-20 kg for 4-6 weeks. Limitation of knee flexion to 90 degrees for 6 weeks. RESULTS: Between 01/2006 and 04/2007, the dorsal medial femoral condyle was used as a donor site in 16 patients. All patients were evaluated preoperatively and after 1 year using the American Knee Society Score (KSS), the Western Ontario and McMaster Universities (WOMAC) Score, the Tegner Score, and the visual analog scale (VAS) pain. The mean follow- up was 13.9 (+/-4.3) months. The mean defect area was 4.6 (+/-2.2) cm(2). The mean KSS, Tegner Score, and WOMAC Score improved from 123.1 (+/-41.5), 2.8 (+/-0.9), and 73.3 (+/-50.2) points preoperatively to 171.3 (+/-16.9), 3.4 (+/-0.6), and 26.1 (+/-17.6) points after 13.9 months (p < 0.05). The VAS pain improved from 5.3 (+/-2.7) to 2.4 (+/-1.8) points (p < 0.05). One patient with an osteochondral defect of 8 cm(2) at the medial femoral condyle (Ahlbäck's disease) still complains of pain during deep squatting. The dorsal medial femoral condyle can be recommended as donor site for OCT. The minimally invasive approach has proven to be safe and simple with a low complication rate.

Long-term effects of saw osteotomy versus random fracturing on bone healing and remodeling in a sheep tibia model.

This article is about the evaluation of possible differences in biomechanical or histomorphological properties of bone healing between saw osteotomy and random fracturing after 6 months. A standardized, 30 degrees oblique monocortical saw osteotomy of sheep tibia was carried out, followed by manual fracture completion of the opposed cortical bone. Fixation was performed by bridge plating (4.5 mm, LCDCP, broad). X-rays were taken immediately after surgery and at the end of the study. Polychrome fluorescent staining was performed according to a standardized protocol in the 2nd, 4th 6th, 10th, 14th, 18th, 22th and 26th week. Ten sheep were comprehensively evaluated. Data for stiffness and histomorphology are reported. The average bending stiffness of the operated bone was higher (1.7 (SD 0.3) with plate (MP) vs. 1.5 without plate) than for the intact bone (1.4 (SD 0.2), though no significant differences in bending stiffness were observed (P>0.05). Fluorescence staining revealed small numbers of blood vessels and less fragment resorption and remodeling in the osteotomy gap. Bone healing after saw osteotomy shows a very close resemblance to 'normal' fracture healing. However, vascular density, fragment resorption, fragment remodeling, and callus remodeling are reduced at the osteotomy.