Porous hydroxyapatite for artificial bone applications

Hydroxyapatite (HA) has been used clinically for many years. It has good biocompatibility in bone contact as its chemical composition is similar to that of bone material. Porous HA ceramics have found enormous use in biomedical applications including bone tissue regeneration, cell proliferation, and drug delivery. In bone tissue engineering it has been applied as filling material for bone defects and augmentation, artificial bone graft material, and prosthesis revision surgery. Its high surface area leads to excellent osteoconductivity and resorbability providing fast bone ingrowth. Porous HA can be produced by a number of methods including conversion of natural bones, ceramic foaming technique, polymeric sponge method, gel casting of foams, starch consolidation, microwave processing, slip casting, and electrophoretic deposition technique. Some of these methods have been combined to fabricate porous HA with improved properties. These combination methods have yielded some promising results. This paper discusses briefly fundamental aspects of porous HA for artificial bone applications as well as various techniques used to prepare porous HA. Some of our recent results on development ofmporous HA will be presented as well

Functional outcome of neurotization to the musculocutaneous nerve in traumatic brachial plexus injury

Introduction: Neurotization procedures to the elbow flexors are commonly done in traumatic brachial plexus injury (BPI). The objective of this study was to evaluate the recovery of elbow flexors in patients who underwent neurotization procedure to musculocutaneous nerve in the panplexus and upper trunk BPI. Materials and Methods: This was a cross sectional study involving 70 patients who underwent neurotization to elbow flexor. A total of 31 patients (44%) had panplexus injury and 39 (56%) had upper trunk BPI. Elbow flexor motor power and post-operative Disabilities of the Arm, Shoulder and Hand (DASH) score were evaluated. Results: The mean age of the patients was 22.7 years. Patients with panplexus BPI underwent neurotization to the elbow flexor using spinal accessory nerve as a donor and patients with upper trunk BPI used either ulnar or median nerve as a donor. The results of elbow flexors recovery in panplexus BPI were good (MRC grade 4 and 5) in 11 patients (35.5%) and poor in 20 patients (64.5%). Conversely, the recovery of elbow flexors in upper trunk BPI were better with 28 patients (71.8%). Good post-operative DASH score (score <50 points) were noted in 29 patients (74.4%) with upper trunk BPI. Only seven patients (22.6%) with panplexus BPI showed good post-operative DASH score. Majority of patients with panplexus BPI demonstrated poor recovery of elbow flexor and post-operative DASH score as compare to upper trunk BPI (p= 0.002). Conclusion: Overall, this study showed significantly better functional outcome of neurotization procedure to elbow flexor in upper trunk BPI than in panplexus BPI

COX-2 inhibitors: a potential target for drug therapy in the management of colorectal cancer

Colorectal cancer is currently the third most common cancer in Malaysia. Elevated expression of COX-2, an induced cyclooxygenase isoenzyme, has been seen in colonic adenomas and colorectal carcinoma. There is evidence that inhibition of this COX-2 can decrease the risk of colorectal cancer. Selective COX-2 inhibitors may have a role in reducing the risk of colorectal cancer in high-risk individuals

Effects of SRY (Sex Determining Region Y)-Box 9 (SOX9) and Telomerase Reverse Transcriptase (TERT) genes transfection in chondrocytes seeded on three-dimensional scaffolds: gross observation and cell proliferation assay

Purpose: To evaluate the formation of in vitro 3D tissue constructs engineered from the SOX9 and TERT genes post-transfected chondrocytes seeded on poly(lactic-co-glycolic acid)(PLGA) based scaffolds. Methods: With the approval of Institutional Animal Care and Use Committee (IACUC,IIUM), the post-transfected rabbits’ chondrocytes were seeded on the prefabricated PLGA with and without fibrin scaffolds. The resulting constructs were cultured for three-week. This experiment setting examined the following groups: (1) non-transfected chondrocytes (control), (2) SOX9-transfected chondrocytes, (3) TERT-transfected chondrocytes and (4) SOX9/TERT-transfected chondrocytes; each seeded on PLGA and PLGA/fibrin scaffolds. All eight groups were evaluated for gross morphology and cells proliferation activity. Results: Grossly, all constructs shrunk in size. The PLGA/fibrin constructs showed a glass-like appearance throughout the culture. The chondrocytes seeded in PLGA/fibrin number showed an increment pattern from day-1 to -21 compared to chondrocytes seeded in PLGA only. The SOX9/TERT-transfected chondrocytes seeded on PLGA/fibrin showed a steadily increased growth pattern comparable to that of control group. Both SOX9 and TERT genes may have synergistic effect in maintaining cell proliferation activity in 3D scaffolds. Overall cellular growth pattern seemed better in PLGA/fibrin than PLGA alone. Besides, PLGA/fibrin constructs exhibited a more stable macroscopic structure throughout the in vitro culture making it a suitable candidate for implantation purpose. Further in vitro study involving construct’s weight, histology analysis, genes expression, biochemical assessments and in vivo implantation are currently underway

Matrix production in chondrocytes transfected with sex determining region Y-Box 9 and telomerase reverse transcriptase genes: an in vitro evaluation from monolayer culture to three-dimensional culture

Background:: This study aimed to observe the cartilaginous matrix production in SRY (sex determining region Y)-box 9 (SOX9)- and/or telomerase reverse transcriptase (TERT)-transfected chondrocytes from monolayer to three-dimensional (3D) culture. Methods:: The genes were transferred into chondrocytes at passage-1 (P1) via lipofection. The post-transfected chondrocytes (SOX9-, TERT- and SOX9/TERT) were analysed at P1, P2 and P3. The non-transfected group was used as control. The 3D culture was established using the chondrocytes seeded in a disc-shaped PLGA/fibrin and PLGA scaffolds. The resulting 3D “cells-scaffolds” constructs were analysed at week-1, -2 and -3. The histoarchitecture was evaluated using haematoxylin and eosin, alcian blue and safranin o stains. The quantitative sulphated glycosaminoglycan (sGAG) content was measured using biochemical assay. The cartilage-specific markers expression were analysed via real-time polymerase chain reaction. Results:: All monolayer cultured chondrocytes showed flattened, fibroblast-like appearance throughout passages. Proteoglycan and sGAG were not detected at the pericellular matrix region of the chondrocytes. The sGAG content assay indicated the matrix production depletion in the culture. The cartilage-specific markers, COL2A1 and ACAN, were downregulated. However, the dedifferentiation marker, COL1A1 was upregulated. In 3D “cells-scaffolds” constructs, regardless of transfection groups, chondrocytes seeded in PLGA/fibrin showed a more uniform distribution and produced denser matrix than the PLGA group especially at week-3. Both sGAG and proteoglycan were clearly visualised in the constructs, supported by the increment of sGAG content, quantitatively. Both COL2A1 and ACAN were upregulated in SOX9/TERT-PLGA and SOX9/TERT-PLGA/fibrin respectively. While, COL1A1 was downregulated in SOX9/TERT-PLGA. Conclusion:: These findings indicated that the SOX9/TERT-transfected chondrocytes incorporation into 3D scaffolds facilitates the cartilage regeneration which is viable structurally and functionally. © 2019, The Korean Tissue Engineering and Regenerative Medicine Society

Viability and glycosaminoglycan content in chondrocytes transfected with SRY (sex-determining region y)-BOX 9 and telomerase reverse transcriptase genes

Glycosaminoglycan (GAG) is a major component of cartilage matrix. This essential polysaccharide has the capacity to attract water molecules. Such capacity is important in cartilage primarily because it absorbs shock and provides lubrication in joint. Cartilage degeneration is often a normal ageing change. Along the process, the cartilage cell; chondrocyte may become less viable and thus, downregulate GAG production. This study evaluates cell viability and GAG content in chondrocytes using monolayer culture model. Chondrocyte usually loses its phenotype after several replications in culture. Hypothetically, replicative senescence contributes to ageing indirectly. Hence, this study compares SOX9 and/or TERT transfected and non-transfected chondrocytes to see whether or not the cells could remain viable and produce GAG after serial passages. While SOX9 is essential for chondrogenesis, TERT is responsible for cells longevity. Upon research approval (IIUM/IACUC/Approval/2015/[5]/[24]), rabbits’ articular cartilages (n=2) were harvested. Isolated chondrocytes were seeded in 6 well-plate with an initial seeding of 5,000 cells/cm2. At passage-1, the chondrocytes were transfected with SOX9 and/or TERT genes via lipofection. The four groups namely non-transfected (control), SOX9-, TERT- and SOX9/TERT-transfected chondrocytes were evaluated at passage-1, -2 and -3. It can be appreciated that the post-transfected chondrocytes have cells viability and GAG content comparable to that of the non-transfected group. They exhibited similar downregulation pattern for viability and GAG content as postulated in theory of ageing. The viability ranged from the highest 93.43% to the lowest 78.49% throughout the culture. The total GAG contents are 25.23μg/ml, 23.87μg/ml, 21.59μg/ml and 23.86μg/ml for SOX9-, TERT-, SOX9/TERT-post-transfected chondrocytes and control, respectively. While cells viability gives an indication that transfection may have non-toxic effect on cells, this study raises some significant questions whether or not SOX9 and TERT could maintain or enhance chondrocyte properties at structural and ultrastructural levels. Detailed investigations into molecular and protein levels are also needed