The use of stem cells in regenerative medicine, including tissue engineering and transplantation, has generated a great deal of enthusiasm. Mesenchymal stromal/stem cells (MSCs) can be isolated from various tissues, most commonly, bone marrow but more recently adipose tissue, dental pulp, and Wharton’s jelly, to name a few. MSCs display varying phenotypic profiles and osteogenic differentiating capacity depending and their site of origin. MSCs have been successfully differentiated into osteoblasts both in vitro an in vivo but discrepancies exist when the two are compared: what happens in vitro does not necessarily happen in vivo, and it is therefore important to understand why these differences occur. The osteogenic process is a complex network of transcription factors, stimulators, inhibitors, proteins, etc., and in vivo experiments are helpful in evaluating the various aspects of this osteogenic process without distractions and confounding variables. With that in mind, the results of in vitro experiments need to be carefully considered and interpreted with caution as they do not perfectly replicate the conditions found within living organisms. This is where in vivo experiments help us better understand interactions that might occur in the osteogenic process that cannot be replicated in vitro. Potentially, these differences could also be exploited to develop an optimal MSC cell therapeutic product that can be used for bone disorders. There are many bone disorders, most of which cause a great deal of discomfort. Clinically acceptable protocols could be developed in which MSCs are used to aid in bone regeneration providing relief for patients with chronic pain. The aim of this review is to examine the differences between studies conducted in vitro and in vivo with regard to the osteogenic process to better define the gaps in current osteogenic research. By better understanding osteogenic differentiation, we can better define treatment strategies for various bone disorders.

中文翻译：

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人间充质基质/干细胞成骨分化的体外和体内比较

干细胞在再生医学（包括组织工程和移植）中的应用引起了极大的热情。间充质基质/干细胞 (MSC) 可以从各种组织中分离出来，最常见的是骨髓，但最近也有脂肪组织、牙髓和沃顿胶等。间充质干细胞表现出不同的表型特征和成骨分化能力，这取决于它们的起源部位。间充质干细胞已在体外和体内成功分化为成骨细胞，但比较两者时存在差异：体外发生的情况不一定发生在体内，因此了解为什么会发生这些差异非常重要。成骨过程是一个由转录因子、刺激物、抑制剂、蛋白质等组成的复杂网络，体内实验有助于评估该成骨过程的各个方面，而不会干扰和混淆变量。考虑到这一点，体外实验的结果需要仔细考虑和谨慎解释，因为它们不能完美地复制生物体内发现的条件。这就是体内实验帮助我们更好地了解成骨过程中可能发生的相互作用的地方，这些相互作用无法在体外复制。潜在地，这些差异也可用于开发可用于骨疾病的最佳 MSC 细胞治疗产品。骨骼疾病有很多种，其中大多数会引起很大的不适。可以制定临床可接受的方案，其中间充质干细胞用于帮助骨再生，从而缓解慢性疼痛患者的症状。本综述的目的是检查体外和体内研究在成骨过程方面的差异，以更好地确定当前成骨研究的差距。通过更好地了解成骨分化，我们可以更好地确定各种骨疾病的治疗策略。