Azlina Amir Abbas

Human peripheral blood derived mesenchymal stem cells demonstrate similar characteristics and chondrogenic differentiation potential to bone marrow derived mesenchymal stem cells

The use of mesenchymal stem cells (MSCs) for cartilage repair has generated much interest owing to their multipotentiality. However, their significant presence in peripheral blood (PB) has been a matter of much debate. The objectives of this study are to isolate and characterize MSCs derived from PB and, compare their chondrogenic potential to MSC derived from bone marrow (BM). PB and BM derived MSCs from 20 patients were isolated and characterized. From 2 ml of PB and BM, 5.4 ± 0.6 million and 10.5 ± 0.8 million adherent cells, respectively, were obtained by cell cultures at passage 2. Both PB and BM derived MSCs were able to undergo tri‐lineage differentiation and showed negative expression of CD34 and CD45, but positively expressed CD105, CD166, and CD29. Qualitative and quantitative examinations on the chondrogenic potential of PB and BM derived MSCs expressed similar cartilage specific gene (COMP) and proteoglycan levels, respectively. Furthermore, the s‐GAG levels expressed by chondrogenic MSCs in cultures were similar to that of native chondrocytes. In conclusion, this study demonstrates that MSCs from PB maintain similar characteristics and have similar chondrogenic differentiation potential to those derived from BM, while producing comparable s‐GAG expressions to chondrocytes.

Effect of Growth Differentiation Factor 5 on the Proliferation and Tenogenic Differentiation Potential of Human Mesenchymal Stem Cells in vitro

The use of growth differentiation factor 5 (GDF-5) in damaged tendons has been shown to improve tendon repair. It has been hypothesized that further improvements may be achieved when GDF-5 is used to promote cell proliferation and induce tenogenic differentiation in human bone marrow-derived mesenchymal stem cells (hMSCs). However, the optimal conditions required to produce these effects on hMSCs have not been demonstrated in previous studies. A study to determine cell proliferation and tenogenic differentiation in hMSCs exposed to different concentrations of GDF-5 (0, 5, 25, 50, 100 and 500 ng/ml) was thus conducted. No significant changes were observed in the cell proliferation rate in hMSCs treated at different concentrations of GDF-5. GDF-5 appeared to induce tenogenic differentiation at 100 ng/ml, as reflected by (1) a significant increase in total collagen expression, similar to that of the primary native human tenocyte culture; (2) a significant upregulation in candidate tenogenic marker gene expression, i.e. scleraxis, tenascin-C and type-I collagen; (3) the ratio of type-I collagen to type-III collagen expression was elevated to levels similar to that of human tenocyte cultures, and (4) a significant downregulation of the non-tenogenic marker genes runt-related transcription factor 2 and sex determining region Y (SRY)-box 9 at day 7 of GDF-5 induction, further excluding hMSC differentiation into other lineages. In conclusion, GDF-5 does not alter the proliferation rates of hMSCs, but, instead, induces an optimal tenogenic differentiation response at 100 ng/ml.

Fluoroscopy Assisted Minimally Invasive Transplantation of Allogenic Mesenchymal Stromal Cells Embedded in HyStem Reduces the Progression of Nucleus Pulposus Degeneration in the Damaged Interverbal Disc: A Preliminary Study in Rabbits

This study was conducted to develop a technique for minimally invasive and accurate delivery of stem cells to augment nucleus pulposus (NP) in damaged intervertebral discs (IVD). IVD damage was created in noncontiguous discs at L4-L5 level; rabbits (N = 12) were randomly divided into three groups: group I treated with MSCs in HyStem hydrogel, group II treated with HyStem alone, and group III received no intervention. MSCs and hydrogel were administered to the damaged disc under guidance of fluoroscopy. Augmentation of NP was assessed through histological and MRI T2 mapping of the NP after eight weeks of transplantation. T2 weighted signal intensity was higher in group I than in groups II and III (P < 0.05). Disc height index showed maximum disc height in group I compared to groups II and III. Histological score of the degenerative index was significantly (P < 0.05) lower in group I (8.6 ± 1.8) than that in groups II (11.6 ± 2.3) and III (18.0 ± 5.7). Immunohistochemistry staining for collagen type II and aggrecan staining were higher in group I as compared to other groups. Our results demonstrate that the minimally invasive administration of MSCs in hyaluronan hydrogel (HyStem) augments the repair of NP in damaged IVD.

First Series of Exeter Small Stem Primary Total Hip Arthroplasty Minimum 5 Years of Follow-Up

We carried out a prospective study of 47 Exeter (Stryker Inc, Warsaw, Ind) small stem total hip arthroplasty in 42 patients with an average age of 58 years and a mean follow-up of 8.5 years. The Oxford hip score improved from a preoperative mean of 47 to 17 at last follow-up. More than 87% patients had excellent or good Harris hip scores, and 90% were able to walk with little or no pain. Stem subsidence within the cement mantle was observed in 26% of cases, and none showed evidence of aseptic loosening or implant failure. Two stems were removed due to infection. The survival rate of this implant was 95.7% at 10 years. This first series of Exeter small stem showed excellent medium-term results, comparable to its larger counterparts.

Oversized Acetabular Socket Causing Groin Pain After Total Hip Arthroplasty

The causes of groin pain after total hip arthroplasty are numerous, and the condition itself is disabling. Therefore, it is imperative that the cause of the pain is identified and managed appropriately. We report a case where the patient had groin pain after total hip arthroplasty as a result of an oversized cementless acetabular component, which caused a breach in the anterior wall of the acetabulum. The anterior wall of the acetabulum was reconstructed with femoral head allograft, and the patient has been symptom free since.

Three dimensional alginate-fucoidan composite hydrogel augments the chondrogenic differentiation of mesenchymal stromal cells.

Presence of sulfated polysaccharides like heparan sulphate has often been implicated in the regulation of chondrogenesis. However, recently there has been a plethora of interest in the use of non-animal extracted analogs of heparan sulphate. Here we remodeled alginate (1.5%) by incorporating fucoidan (0.5%), a natural sulphated polysaccharide extracted from seaweeds to form a composite hydrogel (Al-Fu), capable of enhancing chondrogenesis of human mesenchymal stromal cells (hMSCs). We confirmed the efficiency of fucoidan incorporation by FTIR and EDX analysis. Further, its ability to support hMSC attachment and chondrogenic differentiation was confirmed by SEM, biochemical glycosaminoglycan quantification, real-time quantitative PCR and immunocytochemical analyses of chondrogenic markers Sox-9, Collagen II, Aggrecan and COMP. Effect of Al-Fu hydrogel on hMSC hypertrophy was also confirmed by the downregulation of hypertrophic genes Collagen X and Runx2. This composite scaffold can hence be used as a cartilage biomimetic biomaterial to drive hMSC chondrogenesis and for other cartilage repair based therapies.

Posttraumatic Avascular Necrosis of the Femoral Head in Teenagers Treated by a Modified Transtrochanteric Rotational Osteotomy : A Report of Three Cases

Posttraumatic necrosis (AVN) of the femoral head in children is the most serious complication of femoral neck fractures in children, although it can also be seen after other injuries to the hip such as dislocations. There are only a few reports on the treatment for posttraumatic AVN, and options for treating this complication in the pediatric population are limited. We report our experience in managing 3 cases of posttraumatic avascular necrosis of the femoral head in teenagers with a modified transtrochanteric rotational osteotomy.

Proliferation and osteogenic differentiation of mesenchymal stromal cells in a novel porous hydroxyapatite scaffold

AIM To compare the effect of bovine bone derived porous hydroxyapatite (BDHA) scaffold on proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells (hMSCs) compared with commercial hydroxyapatite (CHA) scaffold. MATERIALS AND METHODS The porosity and pore size were analyzed using micro-CT. The biocompatibility was demonstrated by alamar blue assay, and cell attachment through SEM and Hoechst staining. The osteogenic differentiation was demonstrated using biochemical assay and osteogenic gene expression. RESULTS BDHA and CHA scaffolds showed porosity of 76.6 ± 0.6 and 64.3 ± 0.3% and pore size diameter of 0.04-0.25 and 0.1-2.6 mm, respectively. hMSCs proliferation, ALP activity, osteocalcin secretion and osteogenic gene expression are comparable in both the scaffolds. CONCLUSION These results demonstrated that BDHA is biocompatible, supports cell adhesion and promotes proliferation and osteogenic differentiation.

Platelet Rich Concentrate Promotes Early Cellular Proliferation and Multiple Lineage Differentiation of Human Mesenchymal Stromal Cells In Vitro

Platelet rich concentrate (PRC) is a natural adjuvant that aids in human mesenchymal stromal cell (hMSC) proliferation in vitro; however, its role requires further exploration. This study was conducted to determine the optimal concentration of PRC required for achieving the maximal proliferation, and the need for activating the platelets to achieve this effect, and if PRC could independently induce early differentiation of hMSC. The gene expression of markers for osteocytes (ALP, RUNX2), chondrocytes (SOX9, COL2A1), and adipocytes (PPAR-γ) was determined at each time point in hMSC treated with 15% activated and nonactivated PRC since maximal proliferative effect was achieved at this concentration. The isolated PRC had approximately fourfold higher platelet count than whole blood. There was no significant difference in hMSC proliferation between the activated and nonactivated PRC. Only RUNX2 and SOX9 genes were upregulated throughout the 8 days. However, protein expression study showed formation of oil globules from day 4, significant increase in ALP at days 6 and 8 (P ≤ 0.05), and increased glycosaminoglycan levels at all time points (P < 0.05), suggesting the early differentiation of hMSC into osteogenic and adipogenic lineages. This study demonstrates that the use of PRC increased hMSC proliferation and induced early differentiation of hMSC into multiple mesenchymal lineages, without preactivation or addition of differentiation medium.

Knee laxity of Malaysian adults: Gender differentials, and association with age and anthropometric measures.

BACKGROUND Knee laxity measurements have been shown to be associated with some medical conditions such as chronic joint pain and collagen tissue diseases. The aim of this study was to determine the effects of demographic factors and anthropometric measures on knee laxity. MATERIALS AND METHODS Data were collected from 521 visitors, staffs and students from the University Malaya Medical Centre and University of Malaya between December 2009 and May 2010. Knee laxity was measured using a KT-1000 arthrometer. Multiple regression analysis was used to find the association of knee laxity with age and anthropometric measures. RESULTS Using ANOVA, knee laxity did not show significant differences among ethnic groups for both genders. The average knee laxity in men was 3.47 mm (right) and 3.49 mm (left); while in women were 3.90 mm (right) and 3.67 mm (left). Knee laxity in women was significantly higher (right knee p<0.01 and left knee p<0.05) than men. Right knee laxity of men was negatively associated with height (p<0.05) and BMI (p<0.05); also a negative association was observed between left knee laxity and BMI (p<0.05). Overweight and obese men had less knee laxity than normal weight and underweight individuals. Elderly men and women (age 55 and above) had lower knee laxity (p<0.01) than young adults (ages 21-39). CONCLUSION These results suggest that age and body size are important factors in predicting knee laxity.