Saliva salivary glands. lectures 1 and 2 and 3 Oral biology. Dr. Varga Gábor

Transcription

1 Saliva salivary glands lectures 1 and 2 and 3 Oral biology Dr. Varga Gábor 2016

2 Composition and functions of saliva No saliva - then what? Sjögren syndrome Irradiation induced atrophy of the acinar parenchyma

3 The digestive tract

4 WATER FLUXES THROUGH THE INTESTINE

5 No saliva Dry lips, dry mouth Difficult to swallow WATER 98% Difficult to chew Difficult to speak Difficult to taste MUCINS GUSTIN

6 Most of the fundamental work on nervous innervation of the salivary glands, stomach and pancreas came from the work of Pavlov and his students Pancreatic fistula with pancreatic juice Beaker

7 Nobel prize Pavlov

8 Nobel prize Palade

9 Nobel prize Palade

10 Nobel prize Palade

11 Submandibular gland below lower jaw SALIVARY GLANDS 1) Intrinsic Glands (Buccal glands): Inside oral cavity 2) Extrinsic Glands: Outside oral cavity; connected via ducts Accessory parotid gland Parotid gland anterior to ear More than 600 minor salivary glands Parotid duct Sublingual gland below tongue

12

13 Major glands Parotid: so-called watery serous saliva rich in amylase, proline-rich proteins Stenson s duct Submandibular gland: more mucinous Wharton s duct Sublingual: viscous saliva ducts of Rivinus; duct of Bartholin

14

15 Minor glands Minor salivary glands are not found within gingiva and anterior part of the hard palate Serous minor glands = von Ebner glands : below the sulci of the circumvallate and folliate papillae of the tongue Glands of Blandin-Nuhn: ventral tongue Palatine, glossopalatine glands are pure mucus Weber glands

16 Embryonic development The parotid: ectoderm (4-6 weeks of embryonic life) The sublingual-submandibular glands: endoderm The submandibular gland around the 6th week The sublingual and the minor glands develop around the 8-12 week Differentiation of the ectomesenchyme Development of fibrous capsule Formation of septa that divide the gland into lobes and lobules

17 Stages of salivary gland development epithelial/mesenchymal interactions Schematic showing prebud, initial bud, pseudoglandular, canalicular and terminal bud stage of development in the SMG. Prebud Initial bud Pseudoglandular Canalicular Terminal bud

18 Antisense oligonucleotides to keratinocyte growth factor receptor (KGFR/Bek) decrease branching morphogenesis of E12 SMGs

19 Individual FGFs and BMPs have distinct morphological effects on isolated epithelium cultured in growth factorreduced Matrigel for 44 hours. FGF1-, FGF4- and FGF10- treated epithelium form duct-like structures, whereas FGF2 and FGF7 promote bud formation. Epithelium treated with FGF8, BMP4 or BMP7 alone do not grow.

20 SMGs treated with rfgfr2b (which binds differentiation factors) for 44 hours show decreased epithelial cell proliferation (A-C) and increased mesenchyme apoptosis (D-F)

21 A model of how FGF7 and FGF10 signaling through FGFR2b regulates morphogenesis. The model summarizes our findings, and the dotted lines show other potential mechanisms: MMP2 may regulate FGFR1 cleavage; FGF1 expression may stimulate both FGFR1 and FGFR2; cofactors or coreceptors may specify the localization of FGF binding and, therefore, where proliferation occurs.

22 Signaling events likely propagate during SMG development

23 A kinetic model incorporating unknown transcription factor (TFx) activation by Eda/Edar signaling

24 The cellular structure of the developed salivary glands: acini and ducts

25 Captured phase-contrast microscope photographs from a 24-hour video showing the dynamics of acinotubular structure formation on the surface of BME.

26 Captured phase-contrast microscope photographs from a 24-hour video showing the dynamics of acinotubular structure formation on the surface of BME

27 Claudin 1 expression indicating tight junction formation of husmg cells grown on Transwell filters (red propidium iodide staining shows cell nuclei) Tran et al., Tissue Eng.

28 Tissue organization of salivary glands Acinus: serosus, mucinosus, mixed Duct: ductus intercalaris, ductus striatus, ductus excretorius, main exretory duct

29 Intercalat Acinus -ed duct Striated duct Excretory duct

30 Parotid serous gland

31 Sublingual mucinous gland

32 Submandibular mixed gland

33 STRUCTURAL ORGANIZATION OF Parotid gland H&E SALIVARY GLANDS Serous acini: well-stained, secretory vesicles visible, the nuclei are round or slightly ovoid, contain large amounts of rough ER. These acini produce a watery secretion. Mucous acini: weakly stained, empty-looking vesicles give these cells a distinct "foamy" or "frothy" appearance, the nuclei are darker and smaller than the nuclei of serous cells, they seem to be "pressed" against the basal limit of the cells and may look flattened with an angular ("edgy") outline. They produce a rather slimy secretion.

34 Within the lobules and between the acini of the parotid there are two types of ducts. Striated ducts are lined by a simple tall columnar epithelium. Intercalated ducts are lined by a simple cuboidal epithelium and connect individual acini to the striated ducts. The main excretory duct conveys the secretory product to one of the external surfaces of the body.

35 SALIVARY CONTROL/food Activation of parasympathetic motor neuron Stimulation of chemoreceptors and mechanoreceptors Increased salivation (watery saliva) Thinking Smelling Tasting

36 Stress / salivation Stress / excitment Sympathetic motor neuron activation/β-adrenergic action Increasing salivation - viscous small volume High in proteins

37 PLC G q M3 PIP 2 IP 3 DAG Ca 2 + Cl - Protein camp β adr camp G S AC ATP

38 Composition - inorganic Na mmol/l Cl mmol/l K mmol/l Ca 1-2 mmol/l P 2-23 mmol/l + HCO mmol/l

39 Electrolyte concentrations in basal and stimulated mixed saliva Plasma Basal Stimulated Na + (mmol/l) K + (mmol/l) Ca 2+ (mmol/l) 2, Cl (mmol/l) HCO 3 (mmol/l) phospate (mmol/l) 1,2 6 4 Mg 2+ (mmol/l) 1, SCN (mmol/l) <0.2 2,5 2 NH 3 (mmol/l) (NH 2 ) 2 CO (mmol/l) 2 7 3,3 2 4 Protein (g/l)

40 Saliva water (almost ) Osmolality Extracellular How to secrete it

41 How to secrete water Actively move ions Sodium and chloride (active anion transport) If possible, conserve sodium (and chloride) by reabsorption

42 Salivation two-stage hypothesis Az acinar cells produce isoosmotic primary saliva Passing through the ductal system reabsorption of electolytes happens without water movement resulting hypoosmotic fluid The composition of saliva depends on the rate of salivary secretion (flow rate)

43 FLOW RATE CURVES OF SALIVA AND THE TWO-STAGE HYPOTHESIS Acini Primary secretion Isotonic Duct Secondary ductal modification Hypotonic HCO 3ˉ K + Cl - HCO 3ˉ Na + Concentration meq/l Saliva H 2 O Cl - Na + HCO 3ˉ HCO 3ˉ Cl - Na + K + K + Na + K + H 2 O Plasma Flow ml/min Cl -

44 Main transporters-channels-pumps Primary pumps : ATP supplied energy liberation supports ion movements against gradient Facilitating transporters: carry various ions or uncharged molecules driven by concentration or electrochemical gradients. Based on the number and direction of moved particules, we may differentiate between uniporters, antiporters and cotransporters Ion channels: in open stage selectively allows certain cations to pass through membranes towards electrochemical gradients Water channels: allows to move water passively through membranes

45 Transporters of salivary glands Acinar transporters Primary secretion NBC AE HCO 3 - HCO 3 - Na + H 2 O H + Na + Cl - NKCC 1 NA-K Na + K + 2Cl - K + K + Cl - HCO 3 - H 2 O AQP Cl- HCO3- Na+ H 2 O ATPase Na + HCO 3 - NHE H 2 CO 3 Na + CO 2 CA H + H 2 O

46 Az acinar cell transporters Basolateral side Na + /K + -ATPase cation/chloridecotransporters: Na + /K + /2Cl - cotransporter Na + /Cl - cotransporter K + /Cl- cotransporter unknown substrate specificity transp. Cl - /HCO 3 - (anion exchangers, AEs, SLC26s) Na + /HCO 3- -cotransporter Na + /H + exchanger (NHE) Ca2 + -activated K + -channels Apical side Cl - -channels intracellular Ca2 + -level sensitive camp-level sensitive extracellular ATP activated Hyperpolarization acivated Channels activated by cell swelling Aquaporin water channels (AQP-5)

47 Transporters in acinar secretion A Na-pump A Na + /K + /2Cl - -cotransporter A Ca2 + -activated K + - and Cl - - channels A Na + follows paracellularly, and water follows transcellularly Modell 1

48 Transporters in acinar secretion A Cl - ion through HCO 3 - /Cl exchanger Carbonic-anhydrase facilitated bicarbonate and H + ion production A Na + /H + -antiporter - (ph)ic regulation Modell 2

49 Transporters in acinar secretion Luminal exit of HCO 3 - instead of Cl - secretion Modell 3

50 Salivary gland transporters Ductal transporters - Electrolyte rescue (enac has a key role) Lumen Interstitium H+ K+ Na+ Cl- Cl- Na+ H+ HCO3- Cl- K+ H+ 3Na+ Na+ 2K+

51 Ductal reabsoroption mechanizms - a ducts are impermeable for water - NaCl reabsorption by (Na K pump, enac és Cl channel participationl) - luminal Na ions exchange for protons (secondary active transport) -luminalis H ions a exchange to K ions (tertiery active transport) Isosmotic primary secretion Na Cl H Na H K 2 K 2 K n a 3 Na Cl 3 Na - Hyposmotic saliva Hiposmotic saliva

52 Acini Primary secretion - isotonic fluid - Duct Secondary ductal modification - hypotonic fluid - Na + 3Na + K + Na + K + 2K + 2Cl - K + 3Na + 2K + Cl - Na + H + HCO - CO 2 CO 2 H + 3 CA HCO - 3 Cl - H 2K + 2 O K + Na+ 3Na + Cl - H 2 O HCO - 3 HCO - 3 H + H 2 O CA CO 2 H + CO Na + Cl - 2K + 3Na + Cl - H + K + Na + 2K + H + 3Na + H 2 O

53 Composition - organic TOTAL PROTEIN TOTAL MUCIN CARBOHYDRATE mg/l mg/l MG1 MG2

54 Organic components of mixed saliva quantity Main function Full protein mg/l Prolin-rich proteins mg/l Caries protective Lysozime 109 mg/l Antimicrobial Lactoferrin na Antimicrobial Sialoperoxidase 3 mg/l Antimicrobial Secretoros IgA 194mg/l Antimicrobial IgG 14 mg/l Antimicrobial IgM 2 mg/l Antimicrobial Statherin na Caries protective Gustin ~ 42-60mg/l Taste sensation facilitation Histatins na Antimicrobial Cystatins na Tissue regeneration Amylase 380 mg/l Digestion Lipase (lingual gland origin) na Digestion Urea 2-6 mmol/l Acid neutralization Glucose 0.05 mmol/l plaque feeding Aminoacids 1-2 mmol/l?

55 No saliva Rampant dental caries Acid buffering HCO - 3 NH 4 (urea and aminoacids)

56 No saliva Erosion of Enamel No remineralisation Ca and PO 4 Ca-binding proteins proline-rich proteins statherin

57 No saliva Extensive and rapid dental caries Antibacterial factors Antibodies (IgA) Sialoperoxidase + SCN Lactoferrin

58 No saliva Candida infections Tissue damage Histatins Cystatins

59 No Saliva Digestive problems Amylase Lingual Gland Lipase

60 Most important causes for hyposalivation disorders Sjögren syndrome and othe and other autoimmun disorders - frequently antiserum against M3 receptors acinar parenchyme distruction Radiotherapy induced distruction acinar parenchyme Systemic diseases and their treatment diabetes mellitus, antihypertensive and anxiolytic drugs Xerostomia frequently only subjective feeling - more frequent in older ages (especially in women after menopausa)

61 Saliva as a diagnostic fluid - future perspectives VERY IMPORTANT LINK, part of the preparation for the exam

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78 Thank you for your attention