Bone marrow extract as a growth supplement for human iliac apophyseal chondrocyte culture

Abstract

Background & objectives:Human bone marrow is rich in various growth factors which may support the chondrocyte growth. This study was conducted to compare the culture characteristics of human growth plate chondrocyte in foetal bovine serum (FBS) and human autologous bone marrow extract (BME) in monolayer culture.Methods:Iliac crest apophyseal cartilage was harvested from four donors, aged between two and nine years, undergoing hip surgery. Chondrocytes were propagated under two culture conditions, with 10 per cent FBS and 10 per cent autologous BME harvested from the same donors. Cells were harvested at 7, 14 and 21 days to assess viability, morphology, cell count and immunocytochemistry.Results:With an initial seeding density of 2500 cells/cm2, the average yield in monolayer cultured with FBS was 3.35 × 105, 5.9 × 105, 14.1 × 105 and BME was 0.66 × 105, 1.57 × 105 and 3.48 × 105 at 7, 14 and 21 days, respectively. Viability was 98.21 per cent with FBS and 97.45 per cent with BME at 21 days. In BME supplemented cultures, hyaline phenotype was maintained up to 21 days. The yield was higher in the FBS supplemented group; however, the phenotype could not be maintained by the FBS group as long as BME group.Interpretation & conclusions:Autologous BME was found to be a safer alternative to FBS for human studies. BME could maintain the hyaline phenotype for a longer time. Ways to enhance the cell yield needs to be explored in future studies.

Insights into in vitro environments for human cartilage tissue engineering

“…The in vitro expansion of chondrocytes, though is a challenging process owing to their limited proliferation capacity, slow doubling time and a higher extracellular matrix to cell ratio 1 2 , compared to other tissues such as neurons or cardiomyocytes, it is relatively simpler to grow and transplant them for a successful engraftment into the defective area, as these do not require activation by electrical signals or membrane potentials to make them functional. In this issue, Balakumar et al 3 have used human autologous bone marrow cell-free extract (BME) to culture human iliac apophyseal chondrocytes, in which maintenance of hyaline phenotype in the BME supplemented cultures for nearly 21 days was demonstrated in contrast to the cultures using foetal bovine serum (FBS) which could not maintain the hyaline phenotype 3 . Although the authors have utilized only human iliac apophyseal chondrocytes, which are physiologically capable of in vivo proliferation until puberty 4 , but they have also included the references pertaining to adult articular-derived chondrocytes in their discussions and while deriving conclusions.…”

“…Expansion of chondrocytes in culture requires several inputs. One amongst them is the culture medium which provides nutrition to the cells and forms the main focus of the study by Balakumar et al 3 . The other two important inputs are scaffolds and physical forces and stimuli.…”

“…However, the ultimate goal of tissue engineering can be achieved only when in vivo transplantation of the hyaline cartilages developed in vitro , using methodologies such as the one described by Balakumar et al 3 , are attempted and the hyaline cartilage phenotype is found to be maintained in vivo for a long period of time even after being subjected to various physical forces, and finally be able to yield a disease-free status. Before a clinical translation is planned on lines of the work of Balakumar et al 3 , the following major points need further consideration:…”

“…( ii ). The number of samples studied by Balakumar et al 3 is only four, and the age group from which the samples were derived was between two and nine years. More samples from donors of different age groups need to be studied to add value to the clinical relevance of the study.…”

“…The reason for taking the bone marrow for a different high-value component or protocol such as the lifesaving haematopoietic stem cell transplantation in comparison to in vitro culture of chondrocytes should be justified. The clinical implications of depriving the bone marrow and necessary clinical procedure-related complications pertaining to the procedure described by Balakumar et al 3 to obtain BME also needs consideration.…”