A Physiological view of in vivo calcium dynamics: The regulation of a nonlinear self-organized system

Staub, J. F.; Tracqui, Philippe; Lausson, S.; Milhaud, G; Perault-Staub, A. M.

doi:10.1016/8756-3282(89)90002-1

Cited by 24 publications

(9 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…not 'targeted' for repairing microdamage) and buffering may be linked in this context, and this may represent a link between Ot.Lc.N/B.Ar, metabolism and remodeling. However, several investigators have favored the hypothesis that bone-lining cells, not osteocytes, manipulate Ca solubility [Parfi tt, 1987;Staub et al, 1989;Parfi tt, 1993b;Talmage et al, 2000;Qiu et al, 2002a] on inactive surfaces in response to Ca-regulating hormones. Nevertheless, mechanisms for mobilizing Ca across quiescent surfaces are probably only important for short-term Ca mobilization (e.g., on the scale of hours, such as between meals) and not for high demand or long-term needs that require bone remodeling to mobilize relatively large amounts of Ca [Bowman and Miller, 2001;Heaney, 2003].…”

Section: Metabolic Rate and Species-or Tissue-specifi C Requirements mentioning

confidence: 99%

Spatial Distribution of Osteocyte Lacunae in Equine Radii and Third Metacarpals: Considerations for Cellular Communication, Microdamage Detection and Metabolism

Skedros

Grunander

Hamrick³

2005

Cells Tissues Organs

View full text Add to dashboard Cite

Osteocytes, which are embedded in bone matrix, are the most abundant cells in bone. Despite the ideal location of osteocytes to sense the local environment and influence bone remodeling, their functions, and the relative importance of these functions, remain controversial. In this study, we tested several hypotheses that address the possibilities that population densities of osteocyte lacunae (Ot.Lc.N/B.Ar) correlate with strain-, remodeling- or metabolism-related aspects of the local biomechanical environments of mid-third diaphyseal equine radii and third metacarpals from skeletally mature animals. Ot.Lc.N/B.Ar data, quantified in multiple cortical locations, were analyzed for possible correlations with (1) structural and material characteristics (e.g., cortical thickness, percent ash, secondary osteon population density, mean osteon cross-sectional area, and predominant collagen fiber orientation), (2) strain characteristics, including prevalent/predominant strain magnitude and mode (tension, compression, shear), (3) hypothesized strain-mode-related microdamage characteristics, which might be perceived by osteocyte ‘operational’ networks, and (4) variations in remodeling dynamics and/or metabolism (i.e. presumably higher in endocortical regions than in other transcortical locations). Results showed relatively uniform Ot.Lc.N/B.Ar between regions with highly non-uniform strain and strain-related environments and markedly heterogeneous structural and material organization. These results suggest that population densities of these cells are poorly correlated with mechanobiological characteristics, including local variations in metabolic rate and strain magnitude/mode. Although osteocytes hypothetically evolved both as strain sensors and fatigue damage sensors able to direct the removal of damage as needed, the mechanisms that govern the distribution of these cells remain unclear. The results of this study provide little or no evidence that the number of osteocyte lacunae has a functional role in mechanotransduction pathways that are typically considered in bone adaptation.

show abstract

Section: Metabolic Rate and Species-or Tissue-specifi C Requirements mentioning

confidence: 99%

Spatial Distribution of Osteocyte Lacunae in Equine Radii and Third Metacarpals: Considerations for Cellular Communication, Microdamage Detection and Metabolism

Skedros

Grunander

Hamrick³

2005

Cells Tissues Organs

View full text Add to dashboard Cite

show abstract

“…Also Ca2' homeostasis has been proposed to be regulated by rhythmic variations in parathyroid hormone, CT and vitamin D [24]. Fasting rats display a circadian pattern of CT secretion with two peaks per 24 h [25], but knowledge is lacking about the periodicity of CT secretion during time ranges of hours or shorter.…”

Section: Resultsmentioning

confidence: 99%

Calcium sensing by human medullary thyroid carcinoma cells

et al. 1994

View full text Add to dashboard Cite

Regulation of the cytoplasmic calcium concentration ([Ca"],) was studied in fura-2-loaded C-cells from two human medullary thyroid carcinomas (MTC). K+ depolarization induced sustained rise of [Ca"], reversed by verapamil. Elevation of external Ca" from 0.5 to 3.0 mM triggered regular oscillations or steady-state increases of [Ca"],. In Ca2'-deficient medium Sr" caused steady-state increase or oscillations of the 340/380 nm fluorescence ratio. The Ca" and S?' actions were partially reversible by verapamil. La'+ and Ce3' elicited transient [Ca"], peaks independent of external Ca'", but no oscillations. The results indicate that human MTC cells express a parathyroid-like CaZ' mobilization and influx of Ca '+. sensor coupled to intracellular A voltage-dependent Ca"' influx may be of importance for the oscillations of [Ca"l,.

show abstract

“…{2}+{3}, pre-crystalline forms, are equivalent to 3% of the Ca pool in bone, while {4} (80 mg Ca), located beyond {3 }, may represent bHA microcrystals whose growth is prevented by absorption of some biological material and which remain reversibly associated with other Ca-P associations at the bone surface. Figure 3, previously reported in Staub et al (1989) summarizes the three kinds of temporal behaviours within the model: constancy, rhythmicity and growth.…”

Section: Controlling Systemmentioning

confidence: 96%

“…:.~:~:~:~:~ accretion absorptionCa influx to interface I::iiiiii! ::i::::Temporal behaviours within the model of Ca metabolism in young rat (fromStaub et al, 1989).…”

mentioning

confidence: 99%

Modelling of in vivo calcium metabolism. I. Optimal cooperation between constant and rhythmic behaviours

1992

Self Cite

View full text Add to dashboard Cite

The relevance of nonlinear dynamics to calcium metabolism led us to reevaluate the role of Ca-regulating hormones in Ca homeostasis. We suggest that, firstly, the main Ca metabolic functions in rat-bone and gut--are organized as dynamic entities able to generate various temporal expressions, including self-oscillating patterns and, secondly, Ca homeostasis results from interaction between both metabolic and hormonal oscillators. Following this schema, a major role for the hormonal system, with its circadian pattern, could be to act directly on metabolic functions or indirectly through feeding behaviour, in order to optimize, coordinate and synchronize the Ca fluxes at ECF level.

show abstract

A Physiological view of in vivo calcium dynamics: The regulation of a nonlinear self-organized system

Cited by 24 publications

References 54 publications

Spatial Distribution of Osteocyte Lacunae in Equine Radii and Third Metacarpals: Considerations for Cellular Communication, Microdamage Detection and Metabolism

Spatial Distribution of Osteocyte Lacunae in Equine Radii and Third Metacarpals: Considerations for Cellular Communication, Microdamage Detection and Metabolism

Calcium sensing by human medullary thyroid carcinoma cells

Modelling of in vivo calcium metabolism. I. Optimal cooperation between constant and rhythmic behaviours

Contact Info

Product

Resources

About