Effect of nerve stimulation, denervation, and duct ligation, on kallikrein content and duct cell granules of the cat's submandibular gland

Canadian Society of Nephrology Commentary on the Kidney Disease Improving Global Outcomes 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder

Purpose of review:

(1) To provide commentary on the 2017 update to the Kidney Disease Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD); (2) to apply the evidence-based guideline update for implementation within the Canadian health care system; (3) to provide comment on the care of children with chronic kidney disease (CKD); and (4) to identify research priorities for Canadian patients.

Sources of information:

The KDIGO 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of CKD-MBD.

Methods:

The commentary committee co-chairs selected potential members based on their knowledge of the Canadian kidney community, aiming for wide representation from relevant disciplines, academic and community centers, and different geographical regions.

Key findings:

We agreed with many of the recommendations in the clinical practice guideline on the diagnosis, evaluation, prevention, and treatment of CKD-MBD. However, based on the uncommon occurrence of abnormalities in calcium and phosphate and the low likelihood of severe abnormalities in parathyroid hormone (PTH), we recommend against screening and monitoring levels of calcium, phosphate, PTH, and alkaline phosphatase in adults with CKD G3. We suggest and recommend monitoring these parameters in adults with CKD G4 and G5, respectively. In children, we agree that monitoring for CKD-MBD should begin in CKD G2, but we suggest measuring ionized calcium, rather than total calcium or calcium adjusted for albumin. With regard to vitamin D, we suggest against routine screening for vitamin D deficiency in adults with CKD G3-G5 and G1T-G5T and suggest following population health recommendations for adequate vitamin D intake. We recommend that the measurement and management of bone mineral density (BMD) be according to general population guidelines in CKD G3 and G3T, but we suggest against routine BMD testing in CKD G4-G5, CKD G4T-5T, and in children with CKD. Based on insufficient data, we also recommend against routine bone biopsy in clinical practice for adults with CKD or CKD-T, or in children with CKD, although we consider it an important research tool.

Limitations:

The committee relied on the evidence summaries produced by KDIGO. The CSN committee did not replicate or update the systematic reviews.

Exogenous melatonin: morphology and kallikrein activity of male Syrian hamster submandibular gland

Seven weeks of daily melatonin administration resulted in substantial reduction of convoluted duct cell granule population and kallikrein activity. Some reduction of intercalated duct cell granules was also observed. Testes weight and size was also dramatically reduced. All these changes were not observed after three weeks of melatonin injection.

Effects of prolonged duct ligation of the rat salivary glands on the activity of trypsin-like protease

The effects of ligation on body weight, protease activity and hair kynurenine content were observed. The body weights of parotid gland(PT)-ligated and of combined submandibular (SM)-, sublingual (SL)- and PT-ligated rats were much less than those of sham-operated controls. However, the weights of SM,SL-ligated rats were similar to those of controls. The activity of trypsin-like protease in the duct-ligated submandibular gland was significantly reduced to 0.3-0.7 per cent of that in controls. Protein concentration also decreased in the duct-ligated submandibular gland. Kynurenine content in the hair of duct-ligated rats was higher than that in controls.

Ultrastructure of the parotid gland in the little brown bat

The ultrastructure of the parotid gland was examined in the little brown bat. The seromucous acinar cells contained abundant granules of variable morphology. These granules were characterized by a submembranous dense layer consisting of fine parallel slats. In some bats, the matrix of the granules was structureless, whereas in others it consisted of closely packed but randomly arranged bundles of tubules. The intercalated ducts had a highly developed rough endoplasmic reticulum, often containing large numbers of intracisternal granules. In contrast, only a few secretory granules were present in the supranuclear cytoplasm. The striated ducts, which exhibited the characteristic basal striations consisting of vertically oriented mitochondria and highly folded plasmalemmas, contained numerous small dense granules in a subluminal band. These granules had a paracrystalline substructure with a periodicity of 8 nm. Excretory ducts strongly resembled striated ducts. They showed the same kind of basal striations and about half their constituent cells contained small paracrystalline granules.

The localization of kallikrein in the dog and guinea-pig submandibular glands

In the dog and guinea-pig submandibular glands kallikrein seems to be present in the striated duct cells. Following sympathetic nerve and in vivo isoproterenol stimulation of the dog and guinea-pig submandibular gland respectively, there is a reduction of kallikrein concentration. Ultrastructurally this reduction corresponds to the decrease of straited duct secretory granules in both species. Parasympathetic stimulation also causes some release of kallikrein from both species.

Demilune cells of the cat submandibular gland; an unlikely source of kallikrein

The functional significance of kallikrein in the salivary gland remains unclear partially because of uncertainty over its precise cellular localization. Kallikrein was thought to originate in acinar cells, until recent evidence from cat and rat localized it primarily to the ducts. The possibility that salivary kallikrein may also be located in demilune cells was investigated in this study. - The total kallikrein content of cat submandibular glands was found to be substantially reduced by sampathetic nerve stimulation; whereas parasympathetic stimulation had no significant effect. These biochemical findings did not correlate with morphological studies that revealed almost complete depletion of the demilune cells secretory granules after stimulation of either division of the autonomic nerve supply. This lack of correlation makes it unlikely that kallikrein is present in the demilune cell secretory granules.