scholarly journals The set point of calcium and the reduction of parathyroid hormone in hemodialysis patients

1996 ◽  
Vol 49 (1) ◽  
pp. 226-231 ◽  
Author(s):  
Madelaine Pahl ◽  
Aquiles Jara ◽  
Jordi Bover ◽  
Mariano Rodriguez ◽  
Arnold J. Felsenfeld
2005 ◽  
Vol 184 (1) ◽  
pp. 241-247 ◽  
Author(s):  
S Bas ◽  
E Aguilera-Tejero ◽  
A Bas ◽  
J C Estepa ◽  
I Lopez ◽  
...  

The influence of secondary hyperparathyroidism (2 HPT) on the set point of the parathyroid hormone (PTH)-Ca2+ curve is controversial. In vitro experiments have shown an increase in the set point. However, clinical studies with hemodialysis patients have provided a variety of results (increases, decreases and no changes in the set point have been reported). The present study was designed to investigate the influence of the progression of 2 HPT on the set point of the PTH-Ca2+ curve. The PTH-Ca2+ curve and the expression of parathyroid calcium receptor (CaR mRNA) and vitamin D receptor (VDR mRNA) have been studied in normal rabbits (group I, n=9) and in nephrectomized rabbits (group II, n=18) at two stages after inducing 2 HPT: 2–3 weeks (group IIA) and 5–6 weeks (group IIB). In group I, the set point of the PTH-Ca2+ curve was 1.63±0.03 mM. A progressive hypocalcemia was detected during the evolution of 2 HPT (groups IIA and IIB). Rabbits from group IIA had a significant (P<0.001) decrease in the set point to values of 1.45±0.02 mM. However, the set point increased significantly in group IIB (P<0.001) to 1.56±0.03 mM. CaR mRNA was similarly decreased in groups IIA (39±12%) and IIB (48±7%). No changes were detected in VDR mRNA. In conclusion, a reduction in the set point of the PTH-Ca2+ curve in response to decreased extracellular Ca2+ was detected in the early phases of 2 HPT. However, with the progression of 2 HPT the set point tended to increase even though extracellular Ca2+ was markedly decreased. The increase in the set point in the course of 2 HPT seems to be a complex process that cannot be fully explained by changes in parathyroid CaR mRNA or VDR mRNA.


1991 ◽  
Vol 260 (2) ◽  
pp. E220-E225 ◽  
Author(s):  
J. Fox

Plasma immunoreactive parathyroid hormone (irPTH) levels increase with aging. This study determined 1) whether NH2-terminal irPTH secretory responses to induced hypocalcemia differ between adult (6-mo-old) and aged (24- to 26-mo-old) male rats and 2) whether a higher set point for irPTH release by Ca is responsible for the elevated irPTH levels with aging. Basal irPTH levels were 68% higher and 1,25-dihydroxyvitamin D3 levels were 44% lower in aged rats. An acutely induced, constant hypocalcemic stimulus [0.32 mM decrement in ionized Ca (Ca2+) for 2 h] was developed in catheterized conscious adult and aged rats by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) infusion using the Ca clamp technique. The initial irPTH secretory response to acute hypocalcemia (5-10 min) was reduced in aged rats (1.9- vs. 3.1-fold increase), suggesting reduced hormone stores. However, higher sustained irPTH levels (30 min to 2 h) were maintained in aged rats, indicating increased irPTH synthesis and release. The EGTA infusion rate necessary to maintain constant hypocalcemia was less in aged rats, suggesting skeletal resistance to PTH. Slow EGTA and Ca infusions were used to determine irPTH secretion at plasma Ca2+ levels from 0.7 to 1.5 mM. In aged rats, irPTH levels were higher at all Ca2+ concentrations, but the set point for irPTH release by Ca2+ was the same as in adult rats. Thus the elevated irPTH secretion in aged rats is not caused by a change in the set point for irPTH release but does result in decreased irPTH stores.


2015 ◽  
Vol 30 (suppl_3) ◽  
pp. iii322-iii322
Author(s):  
Ming Feng ◽  
Elani Streja ◽  
Yoshitsugu Obi ◽  
Jialin Wang ◽  
Melissa Soohoo ◽  
...  

1993 ◽  
Vol 13 (2_suppl) ◽  
pp. 476-479 ◽  
Author(s):  
Fabio Malberti ◽  
Bruno Corradi ◽  
Bruno Pagliari ◽  
Dino Romanini ◽  
Antonietta Gazo ◽  
...  

A high Incidence of adynamic bone disease not related to aluminum Intoxication has been reported In continuous ambulatory peritoneal dialysis (CAPD). Since reduced parathyroid hormone (PTH) secretion may predispose to adynamic bone, we Investigated whether parathyroid gland sensitivity may be depressed In CAPD in comparison with hemodialysis (HD). Thus we determined parathyraid function by the evaluation of the PTH-ionized calcium (ICa) relationship, which was obtained Inducing hypocalcemia and hypercalcemia In 19 CAPD and 18 HD patients with biochemical and histological evidence of mild (MILD) or severe (OF) hyperparathyroidism, but negative stainable bone aluminum. Either CAPD or HD patients with OF showed a shift to the right of the sigmoidal PTH-ICa curve in comparison with patients with MILD, greater set point of calcium, and maximal PTH stimulation and Inhibition. The PTH-lCa curve and the other parathyraid function parameters were not different in CAPD and HD patients within the same bone histological group. In conclusion, our data document that parathyroid gland activity Is stimulated either in CAPD and HD patients with OF, but is not depressed in CAPD patients in comparison with HD patients.


2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Niansong Wang ◽  
Gengru Jiang

Abstract Background and Aims The aim of this retrospective, real-world data based observational study was to evaluate the efficacy, safety profile of paricalcitol in Chinese hemodialysis (HD) patients with secondary hyperparathyroidism (SHPT) under routine clinical practice. Method From the Zemplar Engagement Program (ZEP) database, a total of 668 Chinese hemodialysis patients from 104 dialysis centers between January 2015 and May 2019 were included in the analysis set. Intact parathyroid hormone (iPTH), total serum calcium (Ca), phosphate (P), dosage of intravenous (IV) paricalcitol (Zemplar®) were analyzed and discussed via retrospective analysis of the database during the treatment. The comparison between baseline and end of treatment was made to reveal the fluctuation trend of each biomarker and reflected us with clues of IV paricalcitol’s algorithm in real-world practice. Results Patients were divided into five groups according to the duration of follow-up, which includes Month 0.5-3 (Day 14–90), Month 3-6 (Day 91–180), Month 6-12 (Day 181–360), Month 12-24 (Day 361–720) and Month 24-48 (Day 721–1440). Median iPTH levels decreased from 1183.05 pg/ml at baseline to 676.03 pg/ml at last visit by 30.88% (p &lt; 0.0001). 56.14% of patients had a ≥30% decrease and 29.34% of patients had a ≥50% decrease in iPTH. The proportion of patients achieving the Chinese CKD-MBD Guideline target range (&lt;600 pg/ml) increased from 9.88% at treatment initiation to 40.12% at last observation. Serum Ca levels remained within the normal range throughout the study with only a slight but statistically significant increase in the group of Month 12-24 (P=0.0479). Serum phosphate remained stable in all follow-up groups (P&gt;0.05). Subgroup analyses of 221 patients with hyperphosphatemia at baseline &gt;1.78 mmol/l showed a rapid phosphate reduction from 2.00±0.20 mmol/l to 1.76±0.34mmol/l by 11.64% (P&lt; 0.0001), within the first few weeks, along with the reduction of iPTH. Of all patients, 62.72% experienced a 30% decrease in iPTH within a median time of 16.86 weeks (95% CI, 15.57-17.86), 38.17% experienced a 50% decrease in iPTH within a median time of 21.29 weeks (95% CI, 19.86-23.14). The average weekly dose of paricalcitol was 19.69±8.99ug/week. Total dose of paricalcitol used and baseline iPTH were negatively correlated with the decrease in iPTH. Conclusion This is the first national retrospective real-world observational study since IV paricalcitol is available in China since 2014. It proves that up to 20ug weekly IV paricalcitol treatment is safe and effective in China HD patients with higher iPTH level. Physicians and patients could expect significantly iPTH decrease within 16-21 weeks when IV paricalcitol is initiated. This study also encores the pre-published results of paricalcitol trials and high-quality cohorts, from the real-world perspective. In summary, IV paricalcitol is well tolerated and serves as an effective approach to treat SHPT in Chinese HD patients. Figure.1 Mean iPTH values from baseline to last measurement (pg/ml) Figure.2 iPTH changes compared with baseline stratified by baseline iPTH values (%) Figure.3 Proportion of patients with a &gt;=30% or 50% decrease in parathyroid hormone (%) Figure.4 Changes of iPTH and P from baseline to last measurement in the subgroup of hyperphosphatemia (Mean ± SD); (Hyperphosphatemia, defined as P&gt;1.78 mmol/l)


2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Ibrahim Yildirim ◽  
Ender Hur ◽  
Kemal Magden ◽  
Sevil İlikhan ◽  
Hüseyin Engin ◽  
...  

Objective. Sulphur, similar to phosphorus, is easily attached to organic compounds. The inadequate elimination of sulphate may cause high sulphate concentrations in hemodialysis (HD) patients because sulphate is low in free form in plasma. Although we are well aware of the accumulation of phosphorus in chronic dialysis patients, we do not have an adequate knowledge database about the sulphur compounds. This study was designed to determine the level of sulphate in hemodialysis patients. Materials and Methods. Ninety-four prevalent HD patients and 33 patients without renal failure were included in the study. The serum inorganic sulphate levels were measured by turbidimetric technique. Moreover, the serum level of urea, creatinine, albumin, calcium, phosphorus, and parathyroid hormone concentrations was simultaneously recorded. Results. Mean levels of plasma sulphate were significantly higher (0.56 ± 0.17 mM vs 0.31 ± 0.13 mM, p<0.001) in HD patients. Serum sulphate level correlated with patient’s age, serum albumin, serum BUN and creatinine, and serum phosphorus level in HD patients. Serum sulphate levels were not associated with serum parathyroid hormone levels. Conclusion. Serum sulphate levels were approximately twofold higher in HD patients than in the normal control group. Inorganic sulphate does not seem to accumulate in long-term dialysis patients, and mild increased serum levels of sulphate has no poor clinical outcome in these patients.


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