Enhanced Osteogenic Differentiation of Primary Human Osteoporotic Osteoblasts on a Roughened Titanium Surface by Vitamin K2 and Vitamin D3 Compared to the Differentiation Behaviour of Primary Healthy Human Osteoblasts

The number of patients who require endoprosthetic treatment related to osteoporosis has increased in recent years. Vitamin D3 supplementation has long been standard practice in osteoporosis treatment, while vitamin K2 has gained importance. Using our in vitro model, we compared the osteogenic behaviour of primary healthy human osteoblasts (hOBs) and primary osteoporotic human osteoblasts (hopOBs) under unchanged conditions, with vitamin K2, vitamin D3 and the combined addition. Fluorescence microscopy examinations on a plastic surface and a rough titanium surface structure revealed morphological differences. A quantitative analysis of mineralisation and differentiation was performed using an alizarin red S assay and analysis of alkaline phosphatase activity. It was shown that the hopOBs behave differently morphologically on the titanium surface, while hopOBs are particularly noticeable due to the higher number of cell–cell interactions with vitamin K2. The rough surface led to more pronounced mineralisation of the hopOBs. This effect was pronounced under vitamin K2. Vitamin D3 had an effect in the initial phase of hopOB differentiation. Overall, vitamin K2 had a greater influence on the mineralisation of hopOBs than expected. It must be assumed that vitamin K2 plays a significantly greater role in the metabolism of hopOBs than previously assumed.