Fawzi F. Al-Jassir

Human Stromal (Mesenchymal) Stem Cells from Bone Marrow, Adipose Tissue and Skin Exhibit Differences in Molecular Phenotype and Differentiation Potential

Human stromal (mesenchymal) stem cells (hMSCs) are multipotent stem cells with ability to differentiate into mesoderm-type cells e.g. osteoblasts and adipocytes and thus they are being introduced into clinical trials for tissue regeneration. Traditionally, hMSCs have been isolated from bone marrow, but the number of cells obtained is limited. Here, we compared the MSC-like cell populations, obtained from alternative sources for MSC: adipose tissue and skin, with the standard phenotype of human bone marrow MSC (BM-MSCs). MSC from human adipose tissue (human adipose stromal cells (hATSCs)) and human skin (human adult skin stromal cells, (hASSCs) and human new-born skin stromal cells (hNSSCs)) grew readily in culture and the growth rate was highest in hNSSCs and lowest in hATSCs. Compared with phenotype of hBM-MSC, all cell populations were CD34−, CD45−, CD14−, CD31−, HLA-DR−, CD13+, CD29+, CD44+, CD73+, CD90+,and CD105+. When exposed to in vitro differentiation, hATSCs, hASSCs and hNSSCs exhibited quantitative differences in their ability to differentiate into adipocytes and to osteoblastic cells. Using a microarray-based approach we have unveiled a common MSC molecular signature composed of 33 CD markers including known MSC markers and several novel markers e.g. CD165, CD276, and CD82. However, significant differences in the molecular phenotype between these different stromal cell populations were observed suggesting ontological and functional differences. In conclusion, MSC populations obtained from different tissues exhibit significant differences in their proliferation, differentiation and molecular phenotype, which should be taken into consideration when planning their use in clinical protocols.

Randomized clinical trial of continuous femoral nerve block combined with sciatic nerve block versus epidural analgesia for unilateral total knee arthroplasty.

Pain control following total knee arthroplasty (TKA) is crucial to hasten rehabilitation and decrease morbidity. We evaluated whether there is a difference between epidural infusion and continuous femoral nerve block with respect to postoperative pain control and rehabilitation course. Fifty patients completed the study. There was no statistically significant difference in the pain scores (P=0.33), morphine consumption (P=0.09) mean blood pressure or heart rate (P=0.957, and P=0.716) between groups. The postoperative daily mobilization (P=0.80), knee joint range of motion (P=0.83), and straight leg test (P=0.99) were also similar between both groups. Patients were highly satisfied with their pain management in both groups without statistically significant difference (P=0.98).

In vitro assessment of Function Graded (FG) artificial Hip joint stem in terms of bone/cement stresses: 3D Finite Element (FE) study

BackgroundStress shielding in the cemented hip prosthesis occurs due to the mismatching in the mechanical properties of metallic stem and bone. This mismatching in properties is considered as one of the main reasons for implant loosening. Therefore, a new stem material in orthopedic surgery is still required. In the present study, 3D finite element modeling is used for evaluating the artificial hip joint stem that is made of Function Graded (FG) material in terms of joint stress distributions and stem length.Method3D finite element models of different stems made of two types of FG materials and traditional stems made of Cobalt Chromium alloy (CoCrMo) and Titanium alloy (Ti) were developed using the ANSYS Code. The effects on the total artificial hip joint stresses (Shear stress and Von Mises stresses at bone cement, Von Mises stresses at bone and stem) due to using the proposed FG materials stems were investigated. The effects on the total artificial hip joint system stresses due to using different stem lengths were investigated.ResultsUsing FG stem (with low stiffness at stem distal end and high stiffness at its proximal end) resulted in a significant reduction in shear stress at the bone cement/stem interface. Also, the Von Mises stresses at the bone cement and stem decrease significantly when using FG material instead of CoCrMo and Ti alloy. The stresses’ distribution along the bone cement length when using FG material was found to be more uniform along the whole bone cement compared with other stem materials. These more uniform stresses will help in the reduction of the artificial hip joint loosening rate and improve its short and long term performance.ConclusionFE results showed that using FG stem increases the resultant stresses at the femur bone (reduces stress shielding) compared to metallic stem. The results showed that the stem length has significant effects on the resultant shear and Von Mises stresses at bone, stem and bone cement for all types of stem materials.

The early detection and management of unstable concentric closed reduction of DDH with percutaneous K-wire fixation in infants 6 to 12 months of age.

Background: In some infants with developmental dysplasia of the hip, concentric closed reduction, although initially achievable, cannot be maintained even by casting because of a deficient posterior acetabular wall. Usually, these hips will redislocate in the cast and a rereduction will be necessary, often requiring an open reduction subsequently. Methods: A 3-year retrospective review of 88 infants, (M/F; 14/74) 6 to 12 months of age with 124 dislocated hips, was conducted to assess the efficacy of percutaneous Kirschner wire fixation in achieving permanent hip stability. A “hip-at-risk” instability test was developed to detect potentially unstable hips at the time of closed reduction that might redislocate in the hip spica cast, and these hips were stabilized with a percutaneous K-wire through the greater trochanter into the pelvic bone. Results: The hip instability test was positive in 27 hips and negative in 97. Percutaneous K-wire fixation was used to stabilize 21 hips with a positive hip instability test. All 21 unstable hips that were stabilized with the K-wire technique maintained their concentric reduction and went on to stable development. No K-wire breakage was encountered and only 1 superficial pin tract infection occurred. Conclusions: K-wire stabilization of unstable closed reductions is a safe, reliable technique for maintaining concentric hip reduction in infants 6 to 12 months of age with developmental dislocation of the hips. Level of Evidence: Level II retrospective study.

Biocompatibility properties of polyamide 6/PCL blends composite textile scaffold using EA.hy926 human endothelial cells

Enhancing the cytocompatibility profiles, including cell attachment, growth and viability, of designed synthetic scaffolds, has a pivotal role in tissue engineering applications. Polymer blending is one of the most effective methods for providing new desirable biomaterials for tissue scaffolds. This article reports a novel polyamide 6/poly(ε-caprolactone) (PA6/PCL) blends solution which was fabricated to create composite fibrous tissue scaffolds by varying the concentration ratios of PA6 and PCL. Highly porous blends of fibrous scaffold were fabricated and their suitability as cell-support for EA.hy926 human endothelial cells was studied. Our results demonstrated that the unique nanoscale morphological properties and tune porosity of the blends scaffold were controlled. We found that these properties are mainly dependent on the PA6/PCL blending viscosity value, and the viscosity of the blending solution has an intense effect on the properties of the blends scaffold. The influence of the scaffolds extraction fluids and the scaffold direct contact of both the metabolic viability and the DNA integrity of EA.hy926 endothelial cells, as well as the cell/scaffold interaction analysis by scanning electron microscope, after different co-culturing intervals, demonstrated that PA6/PCL blend scaffolds showed different behaviors. Blend scaffolds of PA6/PCL of 90:10 ratio proved to be excellent endothelial cell carriers, which provided a good cell morphology, DNA integrity and viability, induced DNA synthesis/replication, and enhanced cell proliferation, attachment, and invasion. These results indicate that blends of PA6/PCL composite fibers are a promising 3D substitute for the next generation of synthetic tissue scaffolds that could soon find clinical applications.

Thromboprophylaxis and mortality among patients who developed venous thromboembolism in seven major hospitals in Saudi Arabia

Introduction: Venous thromboembolism (VTE) during hospitalization is a serious and potentially fatal condition. Despite its effectiveness, evidence-based thromboprophylaxis is still underutilized in many countries including Saudi Arabia. Objective of the Study: Our objectives were to determine how often hospital-acquired VTE patients received appropriate thromboprophylaxis, VTE-associated mortality, and the percentage of patients given anticoagulant therapy and adherence to it after discharged. Methods: This study was conducted in seven major hospitals in Saudi Arabia. From July 1, 2009, till June 30, 2010, all recorded deep vein thrombosis (DVT) and pulmonary embolism (PE) cases were noted. Only patients with confirmed VTE diagnosis were included in the analysis. Results: A total of 1241 confirmed VTE cases occurred during the 12-month period. Most (58.3%) of them were DVT only, 21.7% were PE, and 20% were both DVT and PE. 21.4% and 78.6% of confirmed VTE occurred in surgical and medical patients, respectively. Only 40.9% of VTE cases received appropriate prophylaxis (63.2% for surgical patients and 34.8% for medical patients; P < 0.001). The mortality rate was 14.3% which represented 1.6% of total hospital deaths. Mortality was 13.5% for surgical patients and 14.5% for medical patients (P > 0.05). Appropriate thromboprophylaxis was associated with 4.11% absolute risk reduction in mortality (95% confidence interval: 0.24%–7.97%). Most (89.4%) of the survived patients received anticoagulation therapy at discharge and 71.7% of them were adherent to it on follow-up. Conclusion: Thromboprophylaxis was underutilized in major Saudi hospitals denoting a gap between guideline and practice. This gap was more marked in medical than surgical patients. Hospital-acquired VTE was associated with significant mortality. Efforts to improve thromboprophylaxis utilization are warranted.

Quantification Analysis of the Intraoperative Bacterial Contamination Rate and Level in Osteochondral Autografts

Background: Inadvertent contamination of osteochondral (OC) autografts during harvesting and preparation can lead to significant complications and can cause the operating team to weigh the infection risk after reimplantation against discarding the OC fragment. The most commonly reported contamination mechanism is the accidental dropping of an OC fragment; however, associated contamination levels remain unclear. The rate and level of contamination during standard harvesting and preparation are also unknown. Purpose: To quantitatively evaluate the rate and level of bacterial contamination of OC autografts during harvesting and preparation compared with those of accidently dropped autografts. Study Design: Controlled laboratory study. Methods: Under sterile conditions, 138 fresh OC specimens were harvested and retrieved from 23 primary total knee arthroplasties (TKAs). Six OC fragments were retrieved from each TKA: 3 were used as controls, and 3 were dropped onto the operating room floor. Each specimen was incubated to allow for aerobic and anaerobic growth, and the number of colony-forming units (CFUs) per gram was calculated. Results: Contamination rates (positive cultures) for the control and dropped groups were 29% (n = 20/69) and 42% (n = 29/69), respectively. The difference in the contamination rate between groups was not statistically significant (P = .109). The most common organisms identified were Staphylococcus aureus (40%) in the control group and Staphylococcus epidermidis (24.1%) and Bacillus species (20.7%) in the dropped group. The contamination level (CFUs/g) for both groups was low. The median (range) CFUs/g among the contaminated specimens in the dropped and control groups were 27 (1-120) and 3 (1-15), respectively (P < .0001). Conclusion: A relatively high rate of OC autograft contamination can be expected during harvesting and preparation (29%) or after accidentally dropping a specimen (42%). Although the types of organisms isolated differed between specimens contaminated during harvesting and preparation and dropped specimens, the quantification of the autograft contamination level revealed a very low CFUs/g in both cases. Clinical Relevance: The intraoperative autograft contamination level is very low. Hence, in cases of grafts with a known contamination incident, saving and reimplanting them after proper decontamination is recommended over discarding them or using an allograft.