Osteocyte Remodeling of the Perilacunar and Pericanalicular Matrix

Qing, Hai; Bonewald, Lynda F.

doi:10.4248/ijos.09019

Cited by 137 publications

(118 citation statements)

References 29 publications

Supporting

Mentioning

108

Contrasting

Unclassified

Order By: Relevance

“…The results obtained in the present work using this method showed that both tensile and compressive forces cause an early increase in lacunar volume, confirming our observations on routine histologic sections and with bright-field microscopy. In agreement with Bèlanger's findings in the 1960's [Bèlanger, 1969], several authors have reported that osteocytes have the capacity to resorb and replace the perilacunar matrix sur- rounding them, confirming their role in mineral homeostasis [Nakano et al, 2004;Lane et al, 2006;Qing and Bonewald, 2009]. These changes in the perilacunar environment modify the concentration of calcium and phosphate in the periosteocytic space [Harris et al, 2007].…”

Section: Discussionsupporting

confidence: 71%

Histomorphometric Study and Three-Dimensional Reconstruction of the Osteocyte Lacuno-Canalicular Network One Hour after Applying Tensile and Compressive Forces

Bozal

Sánchez

Mandalunis

et al. 2013

Cells Tissues Organs

View full text Add to dashboard Cite

The occurrence of very early morphological changes in the osteocyte lacuno-canalicular network following application of tensile and/or compressive forces remains unknown to date. Thus, the aim of this study was to perform a morphological and morphometric evaluation of the changes in the three-dimensional structure of the lacuno-canalicular network and the osteocyte network of alveolar bone that take place very early after applying tensile and compressive forces in vivo, conducting static histomorphometry on bright-field microscopy and confocal laser scanning microscopy images. Our results showed that both the tensile and compressive forces induced early changes in osteocytes and their lacunae, which manifested as an increase in lacunar volume and changes in lacunar shape and orientation. An increase in canalicular width and a decrease in the width and an increase in the length of cytoplasmic processes were also observed. The morphological changes in the lacuno-canalicular and osteocyte networks that occur in vivo very early after application of tensile and compressive forces would be an indication of an increase in permeability within the system. Thus, both compressive and tensile forces would cause fluid displacement very soon after being applied; the latter would in turn rapidly activate alveolar bone osteocytes, enhancing transmission of the signals to the entire osteocyte network and the effector cells located at the bone surface.

show abstract

Section: Discussionsupporting

confidence: 71%

Histomorphometric Study and Three-Dimensional Reconstruction of the Osteocyte Lacuno-Canalicular Network One Hour after Applying Tensile and Compressive Forces

Bozal

Sánchez

Mandalunis

et al. 2013

Cells Tissues Organs

View full text Add to dashboard Cite

show abstract

“…More recently, the Bonewald lab has revisited this concept and confirmed with modern techniques that osteocytes express osteoclast-related genes and enzymes, and resorb the mineral and proteinaceous matrix that fills their lacunae (733,734). Moreover, they showed that this process occurs during lactation in mice (733,734,998), and when it was blocked by conditional ablation of the PTH/PTHrP receptor from osteocytes, the amount of mineral lost during lactation was 50% of normal (733). This finding may at first glance be an indication that osteocytic osteolysis contributes ϳ50% of the mineral that is resorbed from the skeleton during lactation, with the balance achieved by osteoclast-mediated resorption of trabeculae (FIGURE 5).…”

Section: Animal Datamentioning

confidence: 99%

“…Bone resorption markers decline rapidly while bone formation markers increase (35,477,478,580,956,992,994). Osteocytic osteolysis also ceases, but now osteocytes express osteoblast-specific genes, tetracycline-labeled bands become evident in their lacunae, and the matrix is restored to its prior mineral content (FIGURE 5) (733,734). This anabolic activity of osteoblasts and osteocytes is sustained for several weeks, as a result of which bone strength, mineralization, and microarchitecture improve and may reach prepregnancy values or better.…”

Section: Animal Datamentioning

confidence: 99%

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

Kovacs

2016

Physiological Reviews

366

524

View full text Add to dashboard Cite

During pregnancy and lactation, female physiology adapts to meet the added nutritional demands of fetuses and neonates. An average full-term fetus contains ϳ30 g calcium, 20 g phosphorus, and 0.8 g magnesium. About 80% of mineral is accreted during the third trimester; calcium transfers at 300-350 mg/day during the final 6 wk. The neonate requires 200 mg calcium daily from milk during the first 6 mo, and 120 mg calcium from milk during the second 6 mo (additional calcium comes from solid foods). Calcium transfers can be more than double and triple these values, respectively, in women who nurse twins and triplets. About 25% of dietary calcium is normally absorbed in healthy adults. Average maternal calcium intakes in American and Canadian women are insufficient to meet the fetal and neonatal calcium requirements if normal efficiency of intestinal calcium absorption is relied upon. However, several adaptations are invoked to meet the fetal and neonatal demands for mineral without requiring increased intakes by the mother. During pregnancy the efficiency of intestinal calcium absorption doubles, whereas during lactation the maternal skeleton is resorbed to provide calcium for milk. This review addresses our current knowledge regarding maternal adaptations in mineral and skeletal homeostasis that occur during pregnancy, lactation, and post-weaning recovery. Also considered are the impacts that these adaptations have on biochemical and hormonal parameters of mineral homeostasis, the consequences for long-term skeletal health, and the presentation and management of disorders of mineral and bone metabolism.

show abstract

“…First, even if osteocytes are oriented according to the direction of principal loading, this does not prove that there is a causal relation between load and orientation of the osteocytes. Second, osteocytes are perfectly capable of remodeling their lacunae long after their surrounding matrix has fully calcified [50,51]. In summary, it is theoretically possible that osteocytes are activated through direct sensing of pericellular matrix strains, although no definite experimental evidence is available to support this notion.…”

Section: Osteocytes As Sensors Of Matrix Strainsmentioning

confidence: 95%

Mechanisms of Osteocyte Mechanotransduction

Bakker

Klein‐Nulend

2010

Clinic Rev Bone Miner Metab

View full text Add to dashboard Cite

Healthy bones combine a proper resistance against fracture with a minimum use of material. This property is likely brought about by osteocytes in response to mechanical cues, but it is still unknown how whole bone loads are translated into a signal that can be sensed by the osteocytes. The goal of this chapter is to critically analyze our current knowledge on how bone transduction takes place from the level of mechanical loads placed upon the bone as an organ to activation of a cell.Bone is constantly remodeled by the coordinated action of bone-resorbing osteoclasts and bone-forming osteoblasts. The balance between bone resorption and bone formation determines whether the process of bone remodeling leads to a net gain or loss of bone mass. The number and activity of osteoclasts and osteoblasts are determined by a multitude of factors, such as hormones and cytokines, as well as by locally produced signaling molecules [1-6]. The major source of signaling molecules in bone is likely the osteocytes, which comprise over 90% of the entire bone cell population. Osteocytes are stellate cells, which are embedded within the calcified bone matrix. They form a high number of cell-cell contacts through their long slender cell processes, forming a syncytium capable of rapid transduction of signals. Osteocytes are highly mechanosensitive and alter the production of a multitude of signaling molecules when triggered with a mechanical stimulus, enabling them to locally affect osteoblast and osteoclast activity [7-10]. These properties of the osteocytes not only facilitate the adaptation of bone mass but, importantly, also allow the adaptation of trabecular bone architecture according to the demands of mechanical usage [11,12].Years ago, it has been shown that isolated osteocytes show a stronger response to a mechanical stimulation in the form of a fluid flow than osteoblasts or periosteal fibroblasts [13]. In vivo models, including strained cores of adult dog cancellous bone, embryonic chicken tibiotarsi, mouse ulnae, rat caudal vertebrae, and rat tibiae, as well as experimental tooth movement in rats, have demonstrated that osteocytes in intact bone change their enzyme activity and RNA synthesis rapidly after mechanical loading [14][15][16][17][18][19]. These studies showed that bone loading produces rapid changes in metabolic activity of osteocytes and suggested that osteocytes may indeed function as mechanosensors in bone. A more recent ground-breaking study by Tatsumi et al. [20] showed that the loss of bone following hind limb unloading of mice was prevented when 80% of the osteocytes were ablated, demonstrating that osteocytes not only sense whole bone loads but are also essential transducers of mechanical signals within bone. Bone Fluid Flow TheoryIf we accept that osteocytes are the professional mechanosensing cells of bone, then how do these cells sense

show abstract

Osteocyte Remodeling of the Perilacunar and Pericanalicular Matrix

Cited by 137 publications

References 29 publications

Histomorphometric Study and Three-Dimensional Reconstruction of the Osteocyte Lacuno-Canalicular Network One Hour after Applying Tensile and Compressive Forces

Histomorphometric Study and Three-Dimensional Reconstruction of the Osteocyte Lacuno-Canalicular Network One Hour after Applying Tensile and Compressive Forces

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

Mechanisms of Osteocyte Mechanotransduction

Contact Info

Product

Resources

About