Laboratorní diagnostika (Ca,
fosfáty, PTH, PTHrP, vitamin D,
paraproteiny aj.)
Metabolismus vápníku a
fosfátů
Vápník v lidském těle
• V lidském těle cca 1000 – 1100 g vápníku
• Většina - tvrdé tkáně (– 99 %)
• Velmi malé množství vápníku intracelulárně
• 55 % endoplasmatické retikulum, dále mitochondrie
• Cytoplasmatická koncentrace (10-7 mol.L-1) X krevní plazma (10-3 mol.L-1)
• Regulační a signální role vápenatých iontů
• Svalová kontrakce
• přenos nervového vzruchu
• sekreční mechanismy
• buněčný cyklus a proliferace
• buněčná smrt
• hemokoagulace, atd.
2,5–7,5 mmol/den
Duodenum + jejunum – 90 %
! Nízký příjem – kompenzační mechanismus – ileum a jejunum
Doherty, A.H., C.K. Ghalambor, and
S.W. Donahue. 2015. Evolutionary
Physiology of Bone: Bone Metabolism
in Changing Environments. Physiology
30:17-29.
An interplay between mitochondria, endoplasmic reticulum and cytoplasm
in handling ROS and calcium ions. Briefly, endoplasmic reticulum is the
crucial and major site for calcium storage in cell. Sarco-/endoplasmic
reticulum Ca2+-ATPase represents the most important transport
mechanism for influx of calcium ions. On the other hand, mitochondria
represent the second most important calcium store in the cell. However,
these two organelles are closely connected in calcium handling, mainly in
response to ROS. Increase in ROS levels in the mitochondria, where the
respiratory chain (RCH) represents the major site for creation of ROS,
triggers the ER to release calcium and sensitizes a calcium-releasing
channel in the ER membrane, sending a feedback signal. On the other
hand, process of folding proteins contributes significantly to creation ROS
directly in ER. When incorrect disulfide bonds form, they need to be
reduced by GSH, resulting in a further decrease of GSH/GSSG ratio, altering
the redox state within the ER. Alternatively, misfolded proteins can be
directed to degradation through ER-associated degradation machinery.
Accumulation of misfolded proteins in the ER initiates the unfolded protein
response, which includes involvement of protein kinase RNA-like
endoplasmic reticulum kinase (PERK), inositol-requiring enzyme (IRE), and
activating transcription factor 6 (ATF6). All these proteins influence cellular
responses at different levels (transcription, translation, antioxidant
defence). Calcium ions released from ER during these processes (inositol
1,4,5-trisphosphate receptors (IP3R) and ryanodine receptors (RyR) –
accumulated in membranes with close connection with mitochondria - in
mitochondrial associated membranes (MAMs) trigger mitochondrial ROS
stimulation via stimulation of the tricarboxylic acid cycle. Mitochondria
release calcium ions via mitochondrial sodium/calcium exchanger (mNCX),
influx of calcium ions from cytoplasm in provided by voltage-dependent
anion channel (VDAC) and calcium uniporter. Increased load of
mitochondria with calcium ions stimulate release of cytochrome c and proapoptic
factors via mitochondrial permeability transition pore (mPTP).Orig. Babula
Kopic, S., and J.P. Geibel. 2013. GASTRIC
ACID, CALCIUM ABSORPTION, AND THEIR
IMPACT ON BONE HEALTH. Physiological
Reviews 93:189-268.
NCX - sodium-calcium
exchanger
PMCA - plasma membrane
calcium ATPase
TRPV6 - transient receptor
potential cation channel
subfamily V member 6
Kopic, S., and J.P. Geibel. 2013. GASTRIC
ACID, CALCIUM ABSORPTION, AND THEIR
IMPACT ON BONE HEALTH. Physiological
Reviews 93:189-268.
Bers, D.M. 2008. Calcium cycling and signaling in
cardiac myocytes. In Annual Review of Physiology.
Annual Reviews, Palo Alto. 23-49.
Bers, D.M. 2008. Calcium cycling and
signaling in cardiac myocytes. In Annual
Review of Physiology. Annual Reviews,
Palo Alto. 23-49.
Vápník v séru
• 2.5 mmol.L-1 , resp. 2.2 – 2.6 mmol.L-1 (100 mg.L-1)
• Horní mez 4 – 5 mmol.L-1
• Dolní mez 1 mmol.L-1
• Cca 60 % v difuzibilní formě:
• Filtrována ledvinami
• 50 % ionizované – volné (Ca2+) (1.1 – 1.3 mmol.L-1)
• 10 % v nízkomolekulárních komplexech (citráty, fosfáty, hydrogenuhličitany)
• Cca 40 % v nedifuzibilní formě:
• Proteinově vázané vápenaté ionty
• Albumin 90 %, globuliny 10 %
• Neprochází glomeruly
• Biologicky neaktivní, ALE snadno se uvolní při hypokalcemii
• Hypoalbuminemie – klesá frakce vázaná na albumin (pokles o 10 g.L-1 nevede ke změněně koncentrace ionizovaného vápníku)
• Hyperproteinémie (maligní myelom) – vzestup celkové kalcemie (bez změny koncentrace volného ionizovaného vápníku)
• pH:
• Alkalóza – klesá množství ionizovaného vápníku
• Acidóza – stoupá množství ionizovaného vápníku
• Kompetice H+ a Ca2+ o vazebná místa albuminu
CASR
Kopic, S., and J.P. Geibel. 2013. GASTRIC ACID, CALCIUM
ABSORPTION, AND THEIR IMPACT ON BONE HEALTH.
Physiological Reviews 93:189-268.
DiGirolamo, D.J., T.L. Clemens, and S. Kousteni. 2012.
The skeleton as an endocrine organ. Nature Reviews
Rheumatology 8:674-683.
Kostní tkáň a tři
typy buněk
BMU - basic multicellular unit
90 – 130 dní
Doherty, A.H., C.K. Ghalambor, and
S.W. Donahue. 2015. Evolutionary
Physiology of Bone: Bone Metabolism
in Changing Environments. Physiology
30:17-29.
Remodelace kostní tkáně
• Genetické faktory
• 60 – 80 % množství kostní tkáně determinováno geneticky
• Černoši versus Asiati
• Mechanické faktory
• Mechanické požadavky
• Význam fyzické aktivity
• Cévní/nervové faktory
• Vaskularizace
• Inervace – neuropeptidy a jejich receptory
• Výživové faktory
• Příjem vápníku
• Návyky – káva, kouření, alkohol, nadbytek soli – rizikové faktory osteopenie
• Funkce endokrinního systému
• Kromě výše uvedených také:
• Androgeny
• Estrogeny
• Progesteron
• Inzulin
• Glukokortikoidy
• Růstový hormon – IGF-1/2!
- Snížený příjem vápníku
- Snížený příjem vitamínu D
- Nižší expozice slunci
Lokální remodelace kostní tkáně
• Růstové faktory:
• Polypeptidy produkovány kostní tkání nebo extraoseálně
• Modulace růstu, proliferace, diferenciace
• BMP
• PDGF (Platelet - derived growth factor)
• FGF (Fibroblastic growth factor) – mitogenní účinek na osteoblasty
• EGF (Epidermal growth factor)
• VEGF (Vascular endothelial growth factor) – stimulace angiogeneze a
proliferace endotelu, regenerace (fraktury)
• GM-CSF (Granulocyte / macrophage - colony stimulating factor) –
osteoklastogeneze
• M-CSF (Macrophage-colony stimulating factor) – první fáze osteoklastogeneze
• TNF (Tumor necrosis factor) – stimulace kostní resorpce
• ! OPG
Lokální remodelace kostní tkáně
• Cytokiny – buňky imunitního systému, celá řada úloh (imunitní odpověď, zánět,
hematopoéza, autokrinní/parakrinní efekt, pleiotropní efekt) - RANKL
• Interleukin 1
• Přímá stimulace osteoklastické resorpce
• Inhibice apoptózy osteoklastů
• Interleukin 6
• Stimulace resorpce kosti
• Osteoklastogeneze
• Interleukin 11
• Kostní dřeň
• Stimulace osteoklastogeneze
• Prostaglandiny
• Stimulace resorpce kostní tkáně
• Leukotrieny
Development schema of haematopoietic precursor cell differentiation into mature osteoclasts, which are fused polykaryons arising from multiple (10–20) individual
cells. Maturation occurs on bone from peripheral blood-borne mononuclear cells with traits of the macrophage lineage shown below. M-CSF (CSF-1) and RANKL are
essential for osteoclastogenesis, and their action during lineage allocation and maturation is shown. OPG can bind and neutralize RANKL, and can negatively regulate
both osteoclastogenesis and activation of mature osteoclasts. Shown below are the single-gene mutations that block osteoclastogenesis and activation. Those
indicated in italic font are naturally occurring mutations in rodents and humans, whereas the others are the result of targeted mutagenesis to generate null alleles.
Shown above are the single-gene mutant alleles that increase osteoclastogenesis and/or activation and survival and result in osteoporosis. Note that all of these
mutants represent null mutations with the exception of the OPG and sRANKL transgenic mouse overexpression models (in blue-outlined boxes).
Schematic representation of the mechanism of action of a, pro-resorptive and calcitropic factors; and b, anabolic and anti-osteoclastic factors. RANKL expression is
induced in osteoblasts, activated T cells, synovial fibroblasts and bone marrow stromal cells, and subsequently binds to its specific membrane-bound receptor RANK,
thereby triggering a network of TRAF-mediated kinase cascades that promote osteoclast differentiation, activation and survival. Conversely, OPG expression is induced
by factors that block bone catabolism and promote anabolic effects. OPG binds and neutralizes RANKL, leading to a block in osteoclastogenesis and decreased survival
of pre-existing osteoclasts.
Endokrinní
regulace
kostního
metabolismu
Kopic, S., and J.P. Geibel. 2013. GASTRIC
ACID, CALCIUM ABSORPTION, AND THEIR
IMPACT ON BONE HEALTH. Physiological
Reviews 93:189-268.
Přímý efekt na kostní tkáň? (osteoblasty)
Kopic, S., and J.P. Geibel. 2013. GASTRIC
ACID, CALCIUM ABSORPTION, AND THEIR
IMPACT ON BONE HEALTH. Physiological
Reviews 93:189-268.
Vitamín D
Parathormon
Barret, K.E., Boitano, S., Barman, S.M., Brooks, H.L.
Ganong´s Review of Medical Physiology. 23rd Ed.
McGraw-Hill Companies 2010
PTH1R versus PTH2R
A, PTH secretion by dispersed
normal human parathyroid
cells in culture in response to
varying concentrations of
extracellular calcium. B, The
four-parameter model
describing the inverse
sigmoidal relationship
between extracellular
calcium and PTH secretion.
Parameter 1 is the maximal
secretory rate, parameter 2 is
the slope of the curve at the
midpoint, parameter 3 is the
set point, and parameter 4 is
the minimum secretory rate.
Kopic, S., and J.P. Geibel. 2013. GASTRIC
ACID, CALCIUM ABSORPTION, AND THEIR
IMPACT ON BONE HEALTH. Physiological
Reviews 93:189-268.
OPG – osteoprotegrin; RANK - receptor activator of nuclear factor kB
Kopic S, Geibel JP: GASTRIC ACID,
CALCIUM ABSORPTION, AND THEIR
IMPACT ON BONE HEALTH. Physiol Rev
2013, 93(1):189-268.
DiGirolamo, D.J., T.L. Clemens, and S.
Kousteni. 2012. The skeleton as an
endocrine organ. Nature Reviews
Rheumatology 8:674-683.
DiGirolamo, D.J., T.L. Clemens, and S. Kousteni. 2012. The
skeleton as an endocrine organ. Nature Reviews
Rheumatology 8:674-683.
Parathormonu podobný peptid - hormon (PTHrP)
a hyperkalcémie u nádorových onemocnění
• “ectopic” production by cancers of peptide hormones (ACTH, PTH?)
• PTH? – hyperkalcémie, hypofostatémie (kostní metastázy, nádory
ledvin, plic, některé neuroendokrinní nádory)
• Díky radioimunologickým metodám – PTHrP (↓ PTH versus ↑ PTHrP)
• Fyziologická funkce PTHrP?
• auto-/para-/endokrinie
• ovlivnění enchondrální kostní formace – blokuje vyzrávání chondrocytů
• růst a diferenciace mléčné žlázy, kůže a pankreatických ostrůvků
• relaxace hladkého svalstva
• transepiteliální transport kalcia v placentě
Martin, T.J. 2016.
PARATHYROID HORMONERELATED
PROTEIN, ITS
REGULATION OF
CARTILAGE AND BONE
DEVELOPMENT, AND ROLE
IN TREATING BONE
DISEASES. Physiological
Reviews 96:831-871.
Martin, T.J. 2016. PARATHYROID HORMONE-RELATED PROTEIN, ITS REGULATION OF CARTILAGE AND BONE DEVELOPMENT, AND ROLE
IN TREATING BONE DISEASES. Physiological Reviews 96:831-871.
Martin, T.J. 2016.
PARATHYROID HORMONERELATED
PROTEIN, ITS
REGULATION OF
CARTILAGE AND BONE
DEVELOPMENT, AND ROLE
IN TREATING BONE
DISEASES. Physiological
Reviews 96:831-871.
Intrakrinní funkce – regulace
buněčné proliferace a apoptózy?
Martin, T.J. 2016. PARATHYROID HORMONERELATED
PROTEIN, ITS REGULATION OF
CARTILAGE AND BONE DEVELOPMENT, AND ROLE
IN TREATING BONE DISEASES. Physiological Reviews
96:831-871.
Martin, T.J. 2016.
PARATHYROID
HORMONE-RELATED
PROTEIN, ITS
REGULATION OF
CARTILAGE AND
BONE
DEVELOPMENT, AND
ROLE IN TREATING
BONE DISEASES.
Physiological Reviews
96:831-871.
Martin, T.J. 2016.
PARATHYROID
HORMONE-
RELATED
PROTEIN, ITS
REGULATION
OF CARTILAGE
AND BONE
DEVELOPMENT,
AND ROLE IN
TREATING
BONE
DISEASES.
Physiological
Reviews 96:831-
871.
Martin, T.J. 2016.
PARATHYROID
HORMONE-
RELATED
PROTEIN, ITS
REGULATION OF
CARTILAGE AND
BONE
DEVELOPMENT,
AND ROLE IN
TREATING BONE
DISEASES.
Physiological
Reviews 96:831-
871.
Martin, T.J. 2016. PARATHYROID HORMONERELATED
PROTEIN, ITS REGULATION OF
CARTILAGE AND BONE DEVELOPMENT, AND
ROLE IN TREATING BONE DISEASES.
Physiological Reviews 96:831-871.
cAMP response element
binding (CREB) protein
Kalcitonin
Russell, F.A., R. King, S.J. Smillie,
X. Kodji, and S.D. Brain. 2014.
CALCITONIN GENE-RELATED
PEPTIDE: PHYSIOLOGY AND
PATHOPHYSIOLOGY.
Physiological Reviews 94:1099-
1142.
Deduced model for the roles of CT and α-CGRP in bone formation.
Based on the work of several investigators it is likely that CT inhibits
bone resorption through a direct effect on osteoclasts, and that α-CGRP
activates bone formation through a direct effect on osteoblasts (solid
lines). The negative influence of CT on bone formation however, may
be indirectly mediated by the hypothalamus or by osteoclasts (dashed
lines).
Huebner, A.K., J. Keller, P. Catala-Lehnen, S.
Perkovic, T. Streichert, R.B. Emeson, M. Amling,
and T. Schinke. 2008. The role of calcitonin and
alpha-calcitonin gene-related peptide in bone
formation. Archives of Biochemistry and
Biophysics 473:210-217.
Russell, F.A., R. King, S.J. Smillie, X. Kodji, and S.D. Brain. 2014. CALCITONIN GENE-RELATED PEPTIDE: PHYSIOLOGY AND
PATHOPHYSIOLOGY. Physiological Reviews 94:1099-1142.
Estrogeny/
androgeny
Manolagas, S.C., C.A. O'Brien, and M. Almeida. 2013. The role of estrogen and androgen receptors in bone health and disease. Nat. Rev.
Endocrinol. 9:699-712.
Glukokortikoidy
Weinstein, R.S. 2011. Glucocorticoid-Induced Bone Disease. New England
Journal of Medicine 365:62-70.
- GnRH ! (androgeny/estrogeny)
- IGF-1
- Snížená resorpce vápníku
Osteokalcin
Vitamin K is required for the formation of γ-carboxyglutamic acid
Booth, S. L. et al. (2012) The role of osteocalcin in human glucose metabolism: marker or mediator?
Nat. Rev. Endocrinol. doi:10.1038/nrendo.2012.201
Osteokalcin a jeho
význam v kostním
metabolismu
Chapurlat, R.D., and C.B. Confavreux. 2016.
Novel biological markers of bone: from bone
metabolism to bone physiology. Rheumatology
55:1714-1725.
IGF-1 a kostní
metabolismus
Leptin a jeho vztah ke kostnímu metabolismu
Leptin – klinické
aspekty ve vztahu
ke kostnímu
metabolismu
Karsenty, G., and F. Oury. 2012. Biology
Without Walls: The Novel Endocrinology of
Bone. In Annual Review of Physiology, Vol
74. D. Julius, and D.E. Clapham, editors.
87-105.
Karsenty, G., and F. Oury. 2012. Biology Without Walls: The Novel Endocrinology of Bone. In Annual Review of Physiology, Vol 74.
D. Julius, and D.E. Clapham, editors. 87-105.
Karsenty, G., and F.
Oury. 2012. Biology
Without Walls: The
Novel Endocrinology of
Bone. In Annual Review
of Physiology, Vol 74. D.
Julius, and D.E.
Clapham, editors. 87-
105.
Karsenty, G., and F.
Oury. 2012. Biology
Without Walls: The
Novel Endocrinology of
Bone. In Annual Review
of Physiology, Vol 74. D.
Julius, and D.E.
Clapham, editors. 87-
105.
Oxytocin a kostní metabolismus
Colaianni, G., L. Sun, M. Zaidi, and A. Zallone.
2014. Oxytocin and bone. American Journal of
Physiology-Regulatory Integrative and
Comparative Physiology 307:R970-R977.
Russell, J.T. 2011.
Imaging calcium signals
in vivo: a powerful tool in
physiology and
pharmacology. British
Journal of
Pharmacology
163:1605-1625.
In vivo
calcium
imaging
Russell, J.T. 2011.
Imaging calcium signals
in vivo: a powerful tool in
physiology and
pharmacology. British
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Pharmacology
163:1605-1625.
Markery kostního metabolismu
Chapurlat, R.D., and C.B. Confavreux. 2016.
Novel biological markers of bone: from bone
metabolism to bone physiology. Rheumatology
55:1714-1725.
„Nové“ markery kostního metabolismu
Chapurlat, R.D., and C.B. Confavreux. 2016. Novel biological markers of bone: from bone metabolism to bone physiology.
Rheumatology 55:1714-1725.
Huang, C.L., and O.W. Moe. 2011.
Klotho: a novel regulator of calcium
and phosphorus homeostasis.
Pflugers Archiv-European Journal
of Physiology 462:185-193.
Klotho:
 b-glukuronidáza
- Stárnutí
- Kostní metabolismus
- Abusus alkoholu
- Ateroskleróza
RIA
ELISA
HPLC
Metody
vyšetření při
poruchách
kostního
metabolismu
Paraproteiny
- M proteiny
- Imunoglobulin nebo jeho část
vznikající z klonu lymfoidněplasmatických
buněk bez zřetelné
protilátkové funkce
- IgG, IgA, IgM, lehké/těžké řetězce
- Hematologické malignity, krevní
choroby
A, Polyclonal pattern from a densitometer
tracing of agarose gel: broad-based peak of γ
mobility. B, Polyclonal pattern from
electrophoresis of agarose gel (anode on the
left). The band at the right is broad and extends
throughout the γ area.
A, Monoclonal pattern of serum protein as
traced by a densitometer after
electrophoresis on agarose gel: tall, narrowbased
peak of γ mobility. B, Monoclonal
pattern from electrophoresis of serum on
agarose gel (anode on the left): dense,
localized band representing monoclonal
protein of γ mobility.