Research Highlights
Clay is Good to the Bone – Osteoporosis Disease Model
Institutions:
King Fahd University, Saudi Arabia; Royal College of Surgeons in Ireland Medical University, Bahrain; and the National University of Computer and Emerging Sciences, Pakistan
Team:
Abduljauwad, S.N., Habib, T., and ur-Rehman, H.
Disease Model:
Osteoporosis
Hydrogel:
VitroGel® 3D
The combination of clay microparticles and VitroGel hydrogel appears to promote osteogenesis in human mesenchymal stem cells, portending a potential therapy for degenerative bone loss.
Clay is a mineral composite of fine grains that is plastic when wet but hardens into a more rigid structure when heated under a flame. The chemical composition of clays typically contains aluminum and magnesium silicates and phosphates. Clays can come in a microparticulate form, which has found use in various fields because of the pores and layers comprising these tiny particles.
Because of a certain similarity between clay minerals and bone structures, it has been thought that clays can be used to promote proper cellular growth in bones. In this regard, a team of engineers and doctors from the Middle East tested the hypothesis that clay nanoparticles could induce human mesenchymal stem cells (hMSCs) to undergo osteogenesis, generating more bone tissue. This could be particularly useful in older adults, whose hMSCs tend to produce fat through adipogenesis rather than osteogenesis, which can lead to degenerative bones or osteoporosis.
Thus, the team mixed hMSCs with palygorskite clay, which has a particular ionic composition that was thought to interact with the extracellular matrix (ECM) in such a way as to stimulate osteogenesis in the stem cells. They embedded clay particles into TheWell Biosciences’ VitroGel® 3D hydrogel to create an ECM-like environment. After adjusting this mixture to a 20 mg/μL clay particle-VitroGel 3D solution, they coated the wells of a 24-well plate with it. Next, the scientists cultured hMSCs in these wells with a medium suitable for osteogenesis. After two weeks, alkaline phosphatase (ALP) assays were performed; ALP is an enzyme whose expression correlates with bone formation. Moreover, to confirm the creation of bone-like tissue, the team used Alizarin red staining to look for the presence of calcium deposition, and they also performed RT-PCR to detect the specific mRNAs that should be produced as bone tissue is created.
The team found that when hMSCs were cultured in both VitroGel 3D and clay particles, ALP expression significantly exceeded that when the cells were grown in only one or the other, or neither, of these components. This combination also bolstered calcium deposition. While culturing in VitroGel 3D alone generated a certain amount of bone-like growth, in combination with clay microparticles, this ECM-like environment induced the highest levels of all types of osteogenesis measurements. While osteogenesis-specific mRNA expression did not seem to be enhanced, possible osteogenesis pathways could be stimulated that were not as expected. From these results collectively, the authors deduced that the charged surfaces of the palygorskite clay particles interact with the stem cells in such a way that the stem cells’ cadherins and integrins, key elements of osteogenesis, could be nurtured.
This paper’s data are promising for osteoporosis therapy, and future in vivo studies in animal models will hopefully augment the findings herein.
