Normocalcemia and persistent elevated serum concentrations of 1-84 parathyroid hormone after operation for sporadic parathyroid adenoma: evidence of increased morbidity from cardiovascular disease

Native thiol decreases in patients with asymptomatic primary hyperparathyroidism, especially in the presence of surgery indication

BACKGROUND

Oxidative stress increases in many systemic and endocrine diseases. The effect of increased parathyroid hormone levels (PTH) and the effects of this hormone on oxidative stress in patients with primary hyperparathyroidism (pHPT) is unknown. We aimed to investigate the change of Thiol-disulfide (SH-SS), one of the oxidative stress parameters, in patients diagnosed with pHPT and the usability of this parameter in patients with pHPT.

METHODS

Forty-six patients who recently diagnosed with asymptomatic pHPT and 40 healthy controls were included in this prospective study. In addition to routine examinations for pHPT, serum SH-SS measurements were recorded. The pHPT patients included in the study were divided into two groups as patients with and without surgical treatment indication.

RESULTS

It was observed that the pHPT group had lower total SH and native SH values and higher SS values compared to the control group (P<0.05 for each). Native SH values were found to be lower in pHPT patients who were indicated for surgical treatment compared to those who did not (P<0.05). An independent relationship was found between Native SH and serum calcium, urine calcium and T scores in DEXA level in asymptomatic pHPT patients with surgical treatment indication (P<0.05).

CONCLUSIONS

In our study, native SH level decreases in patients with pHPT, especially in patients with surgical treatment indication for pHPT. The decrease in SH levels, which is a natural antioxidant that protects the body against oxidative stress, and the increase in SS levels in pHPT patients may be another metabolic effect of this disease. Native SH may be helpful in determining the indication for surgical treatment in asymptomatic pHPT patients.

Oxidative stress and angiogenesis in primary hyperparathyroidism

Background

The inappropriate elevation of parathormone (PTH), which regulates the process of angiogenesis in parathyroid tissue, causes the changes of activity of enzymes responsible for the removal of free radicals. Parathyroidectomy (PTX) in patients with primary hyperparathyroidism (PHPT) lowers the level of PTH and leads to the reduction of risk of cardiovascular and all-cause mortality by normalization of the antioxidant status. Therefore, the aims of the study were to assess the activity of antioxidant enzymes and free radical reaction products in patients after parathyroidectomy, and to evaluate the correlation between the systemic oxidative stress and angiogenic parameters.

Materials and methods

Patients with PHPT treated surgically were enrolled into the study. Total antioxidant capacity (TAC), total oxidative status (TOS), oxidative stress index (OSI), superoxide dismutase (SOD), ceruloplasmin (CER), lipid hydroperoxides (LHP) and malondialdehyde (MDA) were measured before and after parathyroidectomy. The immunohistological expression of angiogenic factors in parathyroid specimens was assessed by the BrightVision method from ImmunoLogic using murine monoclonal anti-human: anti-VEGF, anti-CD31 and anti-CD106 antibodies.

Results

The significant increase of TAC, CER, reduction of TOS, MDA, SOD, especially for cytoplasmic form, and significant decrease of OSI, LHP were observed after PTX. There was no significant correlation between changes of oxidative stress markers and angiogenic parameters: VEGF, CD-31, CD-106 in parathyroid tissue. The correlation level was low and medium.

Conclusions

Parathyroidectomy causes down-regulation of lipid peroxidation processes and leads to reduction of oxidative stress in patients with PHPT. The decrease in the OSI is the results of down-regulation of oxidative stress in the postoperative period. The change of the antioxidant status has no impact on angiogenesis processes in parathyroid tissue.

Original Research: Atorvastatin prevents rat cardiomyocyte hypertrophy induced by parathyroid hormone 1-34 associated with the Ras-ERK signaling

We investigated the effects of atorvastatin (Ator) on cardiomyocyte hypertrophy (CMH) induced by rat parathyroid hormone 1-34 (PTH1-34) and Ras-extracellular signal regulated protein kinases 1/2 (ERK1/2) signaling. Rat cardiomyocytes were randomly divided into seven groups: normal controls (NC), PTH1-34 (10(-7) mol/L), Ator (10(-5) mol/L), farnesyl transferase inhibitors-276 (FTI-276, 4 × 10(-5) mol/L), PTH1-34 + Ator, PTH1-34 + FTI-276 and PTH1-34 + Ator + mevalonic acid (MVA, 10(-4) mol/L). After treatment, the hypertrophic responses of cardiomyocytes were assessed by measuring cell diameter, detecting protein synthesis, and single-cell protein content. The concentrations of hypertrophic markers such as atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were measured by ELISA. Protein expressions of ERK1/2, p-ERK1/2 and Ras were detected by western blotting. The results showed that compared with the PTH1-34 group, cellular diameter, 3H-leucine incorporation, single-cell protein content, ANP and BNP concentration decreased by 12.07 µm, 1622 cpm/well, 84.34 pg, 7.13 ng/L and 20.04 µg/L, respectively, and the expressions of Ras and p-ERK1/2 were downregulated in PTH1-34 + Ator group (P < 0.05). Compared to the PTH1-34 + Ator group, the corresponding hypertrophic responses and hypertrophic markers increased by 4.95 µm, 750 cpm/well, 49.08 pg, 3.12 ng/L and 9.35 µg/L, respectively, and the expressions of Ras and p-ERK1/2 were upregulated in the PTH1-34 + Ator + MVA group (P < 0.05). In conclusion, Ator prevents neonatal rat CMH induced by PTH1-34 and Ras-ERK signaling may be involved in this process.

Surgical management of the patient with primary hyperparathyroidism

Abstract: 

The successful surgical management of primary hyperparathyroidism requires a surgeon with a clear understanding of both the embryology and anatomy of the parathyroid glands. While the majority of patients may only have a single diseased gland, there is no 100% confirmation that can be attained in the preoperative period. For this reason, even when imaging is suggestive of a single diseased gland, additional intraoperative adjuncts should be used. Intraoperative parathyroid hormone monitoring is the most commonly used adjunct. When preoperative localization is not possible, or intraoperative parathyroid hormone levels fail to meet criteria for successful resection, the patient requires a four gland exploration. Cure is not confirmed until normocalcemia is documented for at least 6 months after surgery.

Short-term teriparatide treatment does not affect NT-proBNP, a marker of cardiac disease

BACKGROUND

Teriparatide (Parathyroid hormone (PTH) 1-34) has been shown to increase bone mineral density (BMD) and reduce the risk of vertebral fractures when given intermittently. In contrast primary hyperparathyroidism (PHPT) is associated with increased bone loss. Moreover an increased occurrence of cardiovascular disease (CVD) is seen in PHPT patients. The N-terminal fragment of the pro-peptide of Brain Natriuretic peptide (NT-proBNP), a risk marker of CVD, has been shown to be elevated in PHPT patients, indicating that continuously high concentrations of PTH affect the heart. Therefore the aim of this study was to investigate whether teriparatide treatment is associated with changes in plasma NT-proBNP.

METHODS

A total of 42 patients receiving teriparatide treatment were included in the study. Blood samples were taken at baseline, and after 1, 3 and 6 months of treatment. Plasma concentrations of NT-proBNP were measured. Plasma concentrations of ionized calcium, PTH and alkaline phosphatase (ALP) were also analyzed, and BMD for the lumbar spine and total hip was recorded at baseline and after 6 months.

RESULTS

Data from 10 men and 32 women, mean age 68 years, were included in the analysis. No effect of teriparatide on plasma concentrations of NT-proBNP was observed at any time points. Ionized calcium and ALP concentrations in the plasma increased after 6 months of treatment, whereas PTH concentrations decreased. Spine BMD T-score was significantly increased after 6 months of treatment.

CONCLUSION

After 6 months of treatment with teriparatide, it did not change the concentration of NT-proBNP in plasma, suggesting that intermittent exposure to therapeutic levels of teriparatide does not affect heart function.

Secondary hyperparathyroidism: benign bystander or culpable contributor to adverse health outcomes?

Elevation in serum parathyroid hormone (PTH) often accompanies vitamin D deficiency and renal impairment. PTH elevation in renal failure is viewed as an unfavorable development. Evidence is increasing that PTH elevation may be associated with increased morbidity and mortality. In many instances these PTH effects appear to be independent of vitamin D status. PTH mediates its effects through the ubiquitous type 1 PTH/PTH-related peptide receptor, which is notably present in the cardiovascular system. Increased PTH may promote cardiovascular disease through diminished cardiac contractility, enhanced coronary risk, and cardiac valvular and vascular calcification. High PTH levels appear to be linked to the metabolic syndrome and are aligned with hyperlipidemia, decreased insulin sensitivity, and, perhaps, decreased insulin secretion. Increased PTH also is associated with neuroendocrine activation, increased sympathetic activity, and endothelial stress. The relation between PTH and vitamin D is complex and may show significant threshold variations, especially when calcium intake, age, and race are considered. Moreover, evidence is increasing that fragments of PTH may not only be hormonally active but also may have opposing effects to PTH. Despite these caveats, PTH values provide useful clinical diagnostic and prognostic information in monitoring many chronic ailments such as heart and renal failure and multiple sclerosis.

[Primary hyperparathyroidism. Postoperative normocalcemic hyperparathyrinemia after curative parathyroidectomy]

INTRODUCTION

Normocalcemic hyperparathyrinemia, i.e. elevated parathyroid hormone (PTH) levels after parathyroidectomy in patients with primary hyperparathyroidism (pHPT) may occur in the course of postoperative recovery without the development of persistence or relapse.

MATERIALS, METHODS AND RESULTS

Intraoperative and long-term (7 year) postoperative PTH and calcium levels after curative parathyroidectomy are demonstrated on the basis of a case report of a 62-year-old female patient with severe pHPT and pronounced osseous and renal manifestations. The intraoperative PTH gradient displayed a decrease from 1072 pg/ml to 13 pg/ml (normal range 11-67 pg/ml) followed by an increase of up to 287 pg/ml. The hyperparathyoid values decline to subnormal levels on administration of calcium and vitamin D and increase again after tapering these medications. The inverse calcium/PTH correlation in the course of the 7-year observation period suggests an intact feed-back mechanism. Preoperative PTH screening was performed in 316 consecutive normocalcemic thyroid patients to evaluate the rate of incidental hyperparathyroidism in patients with normal serum calcium levels. Of these patients 31 (9.8%) with normocalcemia (average 2.28 mmol/l, normal range 2.1-2.7 mmol/l) exhibited increased PTH levels averaging 84.2 pg/ml. A parathyroid adenoma was found intraoperatively as the cause for normocalcemic pHPT in only 1 of these 31 patients.

DISCUSSION AND CONCLUSIONS

A review of the literature revealed that late postoperative elevated parathyroid hormone levels after successful pHPT surgery occur in 21.5%. Multiple causes are discussed, e.g. reactive hyperparathyroidism in cases of relative hypocalcemia, hungry bone syndrome, vitamin D deficiency, renal dysfunction and ethnic or lifestyle differences. In mild cases of postoperative hyperparathyrinemia observation of the patient may be sufficient. In cases of reactive hyperparathyroidism due to hypocalcemia, administration of calcium is indicated, in symptomatic patients, additional administration of vitamin D or calcitriol is necessary. Vitamin D deficiency per se needs adequate substitution. In cases of ongoing hyperparathyrinemia an interdisciplinary diagnostic and therapeutic approach is required.

Endothelial function and endothelial nitric oxide synthase intron 4a/b polymorphism in primary hyperparathyroidism

BACKGROUND AND AIM

Patients with symptomatic primary hyperparathyroidism (pHT) have increased cardiovascular morbidity and mortality. Endothelial nitric oxide synthase (eNOS) intron 4a/b polymorphism is associated with coronary artery disease and hypertension in various populations. Our aim is to evaluate endothelial function in patients with pHT during pre-operative hypercalcemic and post-operative normocalcemic periods and to determine whether intron 4a/b polymorphism of eNOS gene influences endothelial function.

SUBJECTS AND METHODS

Forty patients with pHT (age 48.48+/-11.64 yr) were examined pre-operatively and reexamined 5.8+/-1.9 months after parathyroidectomy. Forty-three healthy subjects (age 47.13+/-8.14 yr) were served as control group. Endothelial function was determined by flow-mediated dilation of brachial artery (FMD). eNOS4a/b polymorphism was detected by polymerase chain reaction.

RESULTS

FMD was significantly lower in patients pre-operatively compared with controls (8.48+/-1.78% vs 19.49+/-2.34%, p<0.001). FMD improved significantly after parathyroidectomy (16.19+/-2.16%, p<0.001 compared with pre-operative measurements), but was still significantly lower than controls (p<0.001). The distribution of eNOS4a/b genotype frequencies was not significantly different between patients and controls. Logistic regression analysis showed that increased serum calcium (>2.47 mmol/l) and PTH concentrations (>7.75 pmol/l) were significant independent predictors of lower FMD (<16.7%). ENOS4a/b polymorphism did not enter in this model.

CONCLUSION

Impaired endothelial function in patients with pHT improves after successful parathyroid surgery. No compelling data are evident to suggest that eNOS4a/b polymorphism modifies the endothelial function in patients with pHT.

The association between parathyroid hormone and mortality in dialysis patients is modified by wasting

BACKGROUND

The association between parathyroid hormone (PTH) level and mortality in dialysis patients is controversial. We hypothesized that wasting, a common condition potentially related to adynamic bone disease, modifies the association of PTH with mortality and cardiovascular events (CVE), respectively.

METHODS

We analysed data from 1255 diabetic haemodialysis patients, participating in the German Diabetes and Dialysis Study between 1998 and 2004. The patients were stratified by the presence or absence of wasting (albumin <or=3.8 versus albumin >3.8 g/dL; BMI <or=23 versus BMI >23 kg/m(2)). Using Cox regression analyses, we calculated the risks of (1) all-cause mortality and (2) CVE according to baseline PTH levels. All analyses were adjusted for age, sex, atorvastatin treatment, duration of dialysis, comorbidity, HbA1c, phosphate, calcium, blood pressure, haemoglobin and C-reactive protein.

RESULTS

Patients had a mean age of 66 +/- 8 years, and 54% were male. Among patients without wasting (albumin >3.8 g/dL, n = 586), the risks of death and CVE during 4 years of follow-up significantly increased by 23% and 20% per unit increase in logPTH. Patients in the highest PTH tertile had a 74% higher risk of death (HR(adj) 1.74, 95% CI 1.27-2.40) and a 49% higher risk of CVE (HR(adj) 1.49, 95% CI 1.05-2.11) compared to patients in the lowest PTH tertile. In contrast, no effect was found in patients with wasting. Accordingly, additional analyses in strata of BMI showed that PTH significantly impacted on death and CVE [HR(logPTH)(adj) 1.15 and 1.14, respectively] only in patients without, but not in patients with, wasting.

CONCLUSIONS

Wasting modifies the association of PTH with adverse outcomes in diabetic dialysis patients. High PTH levels are of concern in the patients without wasting, while the effect of PTH on mortality is nullified in the patients with wasting.

Parathyroid hormone and the cardiovascular system

The classical actions of parathyroid hormone (PTH) are well recognized, but its effects on other target tissues, such as the cardiovascular system, are less appreciated. Several studies have evaluated the effects of PTH in patients with primary hyperparathyroidism in order to understand potential cardiovascular effects in terms of hypertension, cardiovascular mortality, left ventricular function, and endothelial function. We review these studies and evaluate the cellular mechanisms that may affect these outcomes.

Serum ionised calcium and cardiovascular disease in 45-years old men and women followed for 18 years

High level of total serum calcium within the normal range has been associated with increased cardiovascular risk. We wanted to evaluate whether the physiological active ionised form of calcium also was a risk factor for cardiovascular disease (CVD).

METHODS

A total of 974 participants from a health survey in 1981 in Copenhagen had ionised serum calcium and different cardiovascular risk factors measured. The participants were followed until 1999 in The National Hospital Patients Registry and The National Death Registry in Denmark regarding the diagnosis ischemic heart disease (IHD) and a broader definition of CVD. Persons with ionised serum calcium in the highest quintile were compared with persons in the lower four quintiles.

RESULTS

In a univariate analysis persons with ionised serum calcium in the highest quintile had increased risk of IHD (p=0.001) and CVD (p=0.02) compared to persons in the lower quintiles. The increased risk disappeared when gender and cardiovascular confounders were included in a Cox proportional hazards analysis (p=0.20 for IHD and p=0.50 for CVD, respectively). In a separate analysis of men and IHD the result remained insignificant (p=0.07).

CONCLUSIONS

Serum ionised calcium in the upper quintile in women and men together did not seem to be a risk factor in development of IHD and CVD, but a non-significant tendency towards increased risk of IHD was observed in men with ionised calcium in the upper quintile compared to men in the lower four quintiles.

HYPERPARATIROSIS AND CARDIOVASCULAR SYSTEM PATHOLOGY

For many years, hyperparathyroidism, including primary, primarily associated with severe pathology of the osseous system and kidneys, was considered a rare disease. The widespread introduction into the clinical practice of the determination in the blood of calcium, and then parathyroid hormone, and osteodensitometry made it possible to recognize this disease more often and at earlier stages and to treat it more successfully. By now, the specific gravity of mild and asymptomatic forms of hyperparathyroidism has increased from 10-15% in the 1980s to 80%. Conservative management of these forms of hyperparathyroidism requires more thorough research on the prognosis of survival, duration and quality of life, and the risk of developing associated diseases in these patients.

Myocardial perfusion defects and the left ventricular ejection fraction disclosed by scintigraphy in patients with primary hyperparathyroidism

Patients with primary hyperparathyroidism (PHPT) have increased risk of cardiovascular disease. For patients undergoing preoperative parathyroid imaging with 99mTc-sestamibi single photon emission computed tomography (SPECT), we combined cervical SPECT and gated cardiac SPECT to achieve information about the localization of parathyroid adenomas, myocardial perfusion, and the left ventricular ejection fraction (LVEF) at rest. A series of 22 patients with PHPT and no history of myocardial infarction or angina pectoris were recruited consecutively. At 60 minutes after injection of 700 MBq 99mTc-sestamibi, SPECT of the neck and gated myocardial perfusion SPECT were performed at the same time. All of the patients who underwent parathyroidectomy had the parathyroid adenoma localized as predicted from the SPECT. Five patients (23%) had myocardial perfusion defects extending more than 15% (range 15-25%), and they had higher plasma parathyroid hormone levels (p = 0.03), and lower LVEF (p = 0.007) than patients without perfusion defects. We suggest that patients with hyperparathyroidism and suspected cardiovascular disease can undergo 99mTc-sestamibi parathyroid SPECT simultaneously with gated myocardial perfusion SPECT to obtain information about the resting perfusion status and cardiac systolic function. The results from myocardial perfusion SPECT can lead to initiation of cardiovascular treatment and eventually perioperative precautions.

Unilateral surgery for hyperparathyroidism: indications, limits, and late results--new philosophy or expensive selection without improvement of surgical results?

We assessed the "late" results after unilateral parathyroidectomy (PTX) performed for selected indications. From October 1998 throughout March 2001 we operated on 454 patients for hyperparathyroidism (HPT). A positive unifocal (99m)tc-MIBI scan was required for the unilateral approach to be used. Intact parathormone (PTH) measurements were done intraoperatively. Postoperative calcium and PTH serum levels of unilaterally operated patients were checked. Follow-up has been 16.2 months (range 6-40 months). Of the 454 patients, 336 (74.0%) were not eligible for the unilateral approach; and 125 (27.5%) of the 454 patients had renal HPT. Among the 329 patients with primary HPT, 125 (38.0%) were excluded for well established reasons, and in 77 other cases (23.5%) preoperative imaging results did not allow the unilateral approach. Altogether, 126 patients (38.3%) with primary HPT were selected for the unilateral approach. Of the 126 unilateral operations, 8 (6.3%) had to be converted to a bilateral procedure. Among the 118 patients with a unilateral approach, 3 patients have been reoperated for overlooked contralateral disease, and 13 dropped out of the study. A total of 102 postoperative calcium and PTH serum late levels are known: 90 (88.2%) patients had normal levels; 10 (9.8%) had a high PTH level, and 2 (1.9%) had high ionized calcium levels. The failure rate in selected cases was 4.2% (5/118) (three were reoperated, and two had a supranormal postoperative ionized Ca level). Even with stringent indications, the late results of unilateral surgery (95.8% cure rate) barely matched those of conventional bilateral surgery (97.6% cure rate). The economic impact of such a surgical strategy should be clarified.

Serum parathyroid hormone is associated with increased mortality independent of 25-hydroxy vitamin d status, bone mass, and renal function in the frail and very old: a cohort study

Very frail older people constitute an increasing proportion of the aging population and often have vitamin D deficiency and impaired renal function. Primary hyperparathyroidism has been associated with increased mortality, but it is unclear whether secondary hyperparathyroidism is associated with increased mortality independent of renal function and vitamin D status. This study aimed to examine the effect of vitamin D deficiency and secondary hyperparathyroidism on mortality in frail older people after accounting for renal function and general measures of health. We evaluated 842 subjects (182 men with a mean age of 81.9 yr and 660 women with a mean age of 86.2 yr) living in residential aged care facilities in Sydney, Australia in a prospective, cohort study. Over a mean duration of follow-up of 31 months, 345 subjects died. Baseline serum 25-hydroxy vitamin D, serum PTH, and bone ultrasound attenuation were significantly associated with mortality in univariate and multivariate analyses (for PTH, a hazard ratio of 1.39 for time to death) after correcting for age and gender. In multivariate analyses that corrected for health status, nutritional status, and renal function, PTH remained a significant predictor of mortality but not 25-hydroxy vitamin D or bone ultrasound attenuation. Serum PTH appears to be associated with increased mortality in the frail elderly independent of vitamin D status, renal function, bone mass, and measures of general health. The mechanism of this effect requires further investigation.

Elevated serum parathyroid hormone concentration in eucalcemic patients after parathyroidectomy for primary hyperparathyroidism and its relationship to vitamin D profile

Elevation of serum parathyroid hormone (PTH) level in eucalcemic patients after parathyroidectomy for primary hyperparathyroidism has been described in up to 40% of patients, but little is known about its etiology or clinical significance. To better understand the cause of this phenomenon, we studied 49 patients without renal dysfunction or osteomalacia who underwent parathyroidectomy for primary hyperparathyroidism. Patients were categorized into 2 groups based on their serum PTH and calcium levels after parathyroidectomy: (1) elevated PTH with eucalcemia (n = 21), (2) normal PTH with eucalcemia (n = 28). Elevation of serum PTH with eucalcemia after parathyroidectomy occurred in 43% of patients. Patients in group 1 had significantly higher preoperative and postoperative mean serum PTH levels and significantly lower postoperative serum levels of 1,25(OH)(2)D(3), 1,25(OH)(2)D(3)/25(OH)D(3) ratio, and 1,25(OH)(2)D(3)/PTH ratio compared with patients in group 2. Serum PTH in group 1 patients normalized as early as 3 months, but remained elevated in some patients for more than 4 years, and was not associated with development of recurrent hypercalcemia. Normalization of serum PTH in group 1 patients was associated with significant increase in 1,25(OH)(2)D(3) and 1,25(OH)(2)D(3)/PTH ratio. Our data suggest that elevation of serum PTH in eucalcemic patients after parathyroidectomy is a frequently reversible state of resistance of the kidneys to PTH-mediated 1-alpha hydroxylation of 25(OH)D(3) and does not signify subsequent recurrence of hyperparathyroidism.