Labusca Luminita, Zugun-Eloae Florin
National Institute of Research and Development for Technical Physics, Iasi, Romania.
Orthopedics and Traumatology, Emergency County Hospital Saint Spiridon, Iasi, Romania.
Front Vet Sci. 2018 Mar 5;5:35. doi: 10.3389/fvets.2018.00035. eCollection 2018.
Intra-articular adipose tissue deposits known as articular fat pads (AFPs) are described to exist within synovial joints. Their assumed role in normal joint biomechanics is increasingly objectivized by means of advanced methods of functional imaging. AFPs possess structural similarity with body subcutaneous white adipose tissue (WAT), however, seems to be regulated by independent metabolic loops. AFP dimension are conserved during extreme WAT states: obesity, metabolic syndrome, lipodystrophy, and cachexia. Hoffa fat pad (HFP) in the knee is increasingly recognized as a major player in pathological joint states such as anterior knee pain and osteoarthritis. HFP contains numerous population of mesenchymal and endothelial progenitors; however, the possible role of mature adipocytes in the maintenance of stem cell niche is unknown. We propose that AFP is an active component of the joint organ with multifunctional roles in the maintenance of joint homeostasis. Endowed with a rich network of sensitive nervous fibbers, AFPs may act as a proprioceptive organ. Adipokines and growth factors released by AFP-resident mature adipocytes could participate in the maintenance of progenitor stem cell niche as well as in local immune regulation. AFP metabolism may be locally controlled, correlated with but independent of WAT homeostasis. The identification of AFP role in normal joint turnover and its possible implication in pathological states could deliver diagnostic and therapeutic targets. Drug and/or cell therapies that restore AFP structure and function could become the next step in the design of disease modifying therapies for disabling joint conditions such as osteoarthritis and inflammatory arthritis.
关节内的脂肪组织沉积物被称为关节脂肪垫（AFP），存在于滑膜关节内。通过先进的功能成像方法，它们在正常关节生物力学中假定的作用越来越多地得到客观验证。AFP与身体皮下白色脂肪组织（WAT）具有结构相似性，然而，似乎受独立的代谢循环调节。在极端的WAT状态下，即肥胖、代谢综合征、脂肪营养不良和恶病质时，AFP的尺寸保持不变。膝关节的Hoffa脂肪垫（HFP）越来越被认为是诸如膝前疼痛和骨关节炎等病理性关节状态的主要参与者。HFP包含大量间充质和内皮祖细胞群体；然而，成熟脂肪细胞在维持干细胞生态位中的可能作用尚不清楚。我们提出AFP是关节器官的一个活跃组成部分，在维持关节稳态方面具有多种功能。AFP拥有丰富的敏感神经纤维网络，可能作为本体感受器官发挥作用。AFP驻留的成熟脂肪细胞释放的脂肪因子和生长因子可能参与祖干细胞生态位的维持以及局部免疫调节。AFP代谢可能受到局部控制，与WAT稳态相关但独立于WAT稳态。确定AFP在正常关节更新中的作用及其在病理状态下的可能影响，可以提供诊断和治疗靶点。恢复AFP结构和功能的药物和/或细胞疗法可能成为设计针对骨关节炎和炎性关节炎等致残性关节疾病的疾病修饰疗法的下一步。
