Effect of parathyroidectomy on anemia and erythropoietin dosing in end-stage renal disease patients with hyperparathyroidism

Association Between Telomere Shortening and Erythropoietin Resistance in Patients with Chronic Kidney Disease Undergoing Hemodialysis

The relationship between telomere shortening and patients with chronic kidney disease (CKD) has recently been investigated. Although most patients respond adequately to erythropoiesis-stimulating agents (ESAs), approximately 10% do not, and this is referred to as ESA resistance. The aim of our study was to investigate the relationship between telomere shortening and erythropoietin resistance in patients with CKD on hemodialysis. This cross-sectional, comparative, analytical, and observational study was conducted in patients of both sexes over 18 years of age diagnosed with CKD. Two groups of patients were identified. The first group consisted of 40 patients receiving erythropoiesis-stimulating agents with erythropoietin resistance. The second group consisted of 40 patients with the same characteristics but without erythropoietin resistance. Telomere length was measured by real-time PCR. Eighty patients were included in the study. Mean hemoglobin levels were lower in the erythropoietin resistance group (8.8 ± 1.67 vs. 11.95 ± 1.81, p = 0.001). Differences were observed in hematocrit and albumin levels, which were lower in patients with erythropoietin resistance, while PTH levels were higher in this group (788 ± 538.47 vs. 535.65 ± 603.06, p = 0.001). A significant difference in telomere length (T/S) was observed between the two groups, with shorter telomere length in the erythropoietin resistance group (0.45 ± 0.04 vs. 0.56 ± 0.03, p = 0.01). Telomere shortening may be associated with anemia and erythropoietin resistance in patients with CKD undergoing hemodialysis. This relationship suggests the need to explore whether telomere length recovery improves the response to ESAs.

Treatment for secondary hyperparathyroidism focusing on parathyroidectomy

Secondary hyperparathyroidism (SHPT) is a major problem for patients with chronic kidney disease and can cause many complications, including osteodystrophy, fractures, and cardiovascular diseases. Treatment for SHPT has changed radically with the advent of calcimimetics; however, parathyroidectomy (PTx) remains one of the most important treatments. For successful PTx, removing all parathyroid glands (PTGs) without complications is essential to prevent persistent or recurrent SHPT. Preoperative imaging studies for the localization of PTGs, such as ultrasonography, computed tomography, and 99mTc-Sestamibi scintigraphy, and intraoperative evaluation methods to confirm the removal of all PTGs, including, intraoperative intact parathyroid hormone monitoring and frozen section diagnosis, are useful. Functional and anatomical preservation of the recurrent laryngeal nerves can be confirmed via intraoperative nerve monitoring. Total or subtotal PTx with or without transcervical thymectomy and autotransplantation can also be performed. Appropriate operative methods for PTx should be selected according to the patients' need for kidney transplantation. In the case of persistent or recurrent SHPT after the initial PTx, localization of the causative PTGs with autotransplantation is challenging as causative PTGs can exist in the neck, mediastinum, or autotransplanted areas. Additionally, the efficacy and cost-effectiveness of calcimimetics and PTx are increasingly being discussed. In this review, medical and surgical treatments for SHPT are described.

[Evolution of the incidence and results at 12 months of parathyroidectomy: 40 years of experience in a dialysis center with two successive surgical departments]

INTRODUCTION

Secondary hyperparathyroidism remains the main complication of mineral and bone metabolism in patients with chronic kidney disease. In case of resistance to medical treatment (native and active vitamin D, calcium and calcimimetics), surgical parathyroidectomy is indicated. The aim of this retrospective study is to show the evolution of the incidence and results of surgical parathyroidectomy in our center between 1980 and 2020 as patient characteristics, diagnostic and therapeutic strategies have changed.

PATIENTS AND METHODS

We collected data from dialysis patients who had a first surgical parathyroidectomy between 2000 and 2020 (period 2) in the same surgical department and compared them with historical data between 1980 and 1999 (period 1) operated in one other center.

RESULTS

In period 1, 53 surgical parathyroidectomy were performed (2.78/year, 0 to 5, 8.5/1000 patients-year) vs.56 surgical parathyroidectomy in period 2 (2.8/year, 0 to 9, 8/1000 patients-year). The patients of the 2 periods were comparable except for the higher dialysis vintage in period 1 (149±170 vs.89±94 months; P=0.02). In comparison with dialysis patients not requiring surgical parathyroidectomy during the same period, patients who had surgical parathyroidectomy were younger, had higher dialysis vintage and lower diabetes prevalence, but more frequently carriers of glomerulopathy or polycystosis. Systematically performed in period 2, cervical ultrasound identified at least one visible gland in 78.6% of cases while the scintigraphy, performed only in 66% of cases, found at least one gland in 81% of cases. Twelve months after surgery, PTH > 300 pg/mL (marker of secondary hyperparathyroidism recurrence or surgery failure) was present in 30% of patients in period 1 vs. 5.3% in period 2. Hypoparathyroidism was also more frequently observed in period 2 (35.7 vs. 18.8%). Surgical complications were also higher in period 1.

CONCLUSION

Despite therapeutic and strategic advances, severe secondary hyperparathyroidism is still as common as ever. It is favored by excessively high PTH targets, by suboptimal prevention before dialysis and poor tolerance of calcimimetics. The surgical parathyroidectomy is effective and safe in the hands of a specialized team with an ultrasound and scintigraphic preoperative assessment.

Impact of parathyroidectomy among nondiabetic hemodialysis patients with severe hyperparathyroidism

Background

Parathyroidectomy (PTX) is a treatment for hyperparathyroidism (HPT) and has uncertain risks and benefits. The aim of this study was to evaluate the effect of PTX versus nonoperative treatment among nondiabetic hemodialysis patients.

Methods

A retrospective matched cohort study was performed. Each PTX patient was matched with one patient who had severe HPT but rejected PTX. The patients were matched by sex, birth date, date of first dialysis, nondiabetic status, and left ventricular ejection fraction. The serum markers, survival, main adverse cardiovascular and cerebrovascular event (MACCE) rates, and hospitalization were compared between the PTX patients and matched non-PTX patients.

Results

There were 1143 patients at our center in the Chinese National Renal Data System (CNRDS) between 2010 and 2020. Of these, 75 PTX patients were matched with 75 non-PTX patients. Rapid decreases in the mean intact parathyroid hormone, calcium and phosphorus concentrations, and a gradual increase in hemoglobin concentration were observed in the PTX group. The mortality was 2.9 per 100 patient-years in the PTX group and 10.9 per 100 patient-years in the non-PTX group (p < 0.001). Compared with non-PTX patients, PTX patients had an adjusted HR for death of 0.236 (95% CI 0.108–0.518). The cumulative MACCE rates were 6.7 per 100 patient-years in the PTX group and 15.2 per 100 patient-years in the non-PTX group (p < 0.001). The adjusted HR of the occurrence of first MACCE for PTX patients compared with non-PTX patients was 0.524 (95% CI 0.279-0.982). The cumulative hospitalization rates were 50.3 per 100 patient-years in the PTX group and 66.5 per 100 patient-years in the matched non-PTX group (p < 0.001).

Conclusions

Compared with non-PTX patients, PTX was associated with an improvement in the biochemical measures and patient-level outcomes in nondiabetic hemodialysis patients with severe HPT.

Parathyroidectomy Improves the Consumption of Erythropoiesis-Stimulating Agents in Hemodialysis Patients

Secondary hyperparathyroidism (SHPT) is common in end-stage renal disease (ESRD) patients, and it can suppress erythropoiesis. We aimed to investigate the relationship between the consumption of erythropoiesis-stimulating agents (ESAs) and parathyroidectomy (PTX) in ESRD patients with SHPT and to determine the predictors for anemia improvement. The current standard of chronic kidney disease anemia therapy relies on the prescription of iron supplementation, and ESA. We retrospectively analyzed 81 ESRD patients with PTX at Ditmanson Medical Foundation Chiayi Christian Hospital from July 2004 to Dec 2018. The requirement of ESA therapy markedly declined from a dose of 41.6 (interquartile range [IQR], 0−91.2) to 10.3 (IQR, 0−59.5, p = 0.001) unit/kg/week. In addition, 63.7% of patients required iron replacement therapy preoperatively and the proportion reduced to 52.5% after PTX (p < 0.001). The hemoglobin (Hb) level showed an insignificant change from a median value of 10.7 g/dL (9.5−11.6 g/dL) before PTX to 10.5 g/dL (9.6−11.2 g/dL) at 6 months after PTX. A preoperative Hb level ≤ 10 mg/dL (odds ratio [OR], 20.1; 95% confidence interval [CI], 4.71−125, p < 0.001) and transferrin saturation (TSAT) < 25% (OR, 12.8; 95% CI, 2.51−129, p < 0.001) were predictors for anemia improvement. Our study demonstrated that PTX markedly decreased the requirement of ESA. Patients with a low preoperative Hb level or low TSAT showed an increase in the Hb level after PTX. PTX may be considered not only for SHPT with refractory anemia but also for high ESA-dependent patients.

Elevated parathyroid hormone one year after kidney transplantation is an independent risk factor for graft loss even without hypercalcemia

Background

Hypercalcemic hyperparathyroidism has been associated with poor outcomes after kidney transplantation (KTx). However, the clinical implications of normocalcemic hyperparathyroidism after KTx are unclear. This retrospective cohort study attempted to identify these implications.

Methods

Normocalcemic recipients who underwent KTx between 2000 and 2016 without a history of parathyroidectomy were included in the study. Those who lost their graft within 1 year posttransplant were excluded. Normocalcemia was defined as total serum calcium levels of 8.5–10.5 mg/dL, while hyperparathyroidism was defined as when intact parathyroid hormone levels exceeded 80 pg/mL. The patients were divided into two groups based on the presence of hyperparathyroidism 1 year after KTx. The primary outcome was the risk of graft loss.

Results

Among the 892 consecutive patients, 493 did not have hyperparathyroidism (HPT-free group), and 399 had normocalcemic hyperparathyroidism (NC-HPT group). Ninety-five patients lost their grafts. Death-censored graft survival after KTx was significantly lower in the NC-HPT group than in the HPT-free group (96.7% vs. 99.6% after 5 years, respectively, P < 0.001). Cox hazard analysis revealed that normocalcemic hyperparathyroidism was an independent risk factor for graft loss (P = 0.002; hazard ratio, 1.94; 95% confidence interval, 1.27–2.98).

Conclusions

Normocalcemic hyperparathyroidism 1 year after KTx was an independent risk factor for death-censored graft loss. Early intervention of elevated parathyroid hormone levels may lead to better graft outcomes, even without overt hypercalcemia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02840-5.

Erythropoietin-Stimulating Agent Hyporesponsiveness in Patients Living with Chronic Kidney Disease

BACKGROUND

Erythropoietin-stimulating agent (ESA) hyporesponsiveness is commonly observed in patients with anemia secondary to chronic kidney disease (CKD). Because of its complexity, a global consensus on how we should define ESA hyporesponsiveness remains unavailable. The reported prevalence and demographic information on ESA hyporesponsiveness within the CKD population are variable with no consensus definition.

SUMMARY

ESA hyporesponsiveness is defined as having no increase in hemoglobin concentration from baseline after the first month of treatment on appropriate weight-based dosing. The important factors associated with ESA hyporesponsiveness include absolute or functional iron deficiency, inflammation, and uremia. Hepcidin has been demonstrated to play an important role in this process. Mineral bone disease secondary to CKD and non-iron malnutrition among other factors are also associated with ESA hyporesponsiveness. There is continued debate toward determining a gold-standard treatment pathway to manage ESA hyporesponsiveness. The development of hypoxia-inducing factor-stabilizers brings new insights and opportunities in the management of ESA hyporesponsiveness.

KEY MESSAGE

Management of ESA hyporesponsiveness involves a comprehensive multidisciplinary team approach to address its risk factors. The progression of basic and clinical research on identifying risk factors and management of ESA hyporesponsiveness brings greater hope on finding solutions to eventually tackling one of the most difficult problems in the topic of anemia in CKD.

Effects of hypoxia on bone metabolism and anemia in patients with chronic kidney disease

BACKGROUND

Abnormal bone metabolism and renal anemia seriously affect the prognosis of patients with chronic kidney disease (CKD). Existing studies have mostly addressed the pathogenesis and treatment of bone metabolism abnormality and anemia in patients with CKD, but few have evaluated their mutual connection. Administration of exogenous erythropoietin to CKD patients with anemia used to be the mainstay of therapeutic approaches; however, with the availability of hypoxia-inducible factor (HIF) stabilizers such as roxadustat, more therapeutic choices for renal anemia are expected in the future. However, the effects posed by the hypoxic environment on both CKD complications remain incompletely understood.

AIM

To summarize the relationship between renal anemia and abnormal bone metabolism, and to discuss the influence of hypoxia on bone metabolism.

METHODS

CNKI and PubMed searches were performed using the key words "chronic kidney disease," "abnormal bone metabolism," "anemia," "hypoxia," and "HIF" to identify relevant articles published in multiple languages and fields. Reference lists from identified articles were reviewed to extract additional pertinent articles. Then we retrieved the Abstract and Introduction and searched the results from the literature, classified the extracted information, and summarized important information. Finally, we made our own conclusions.

RESULTS

There is a bidirectional relationship between renal anemia and abnormal bone metabolism. Abnormal vitamin D metabolism and hyperparathyroidism can affect bone metabolism, blood cell production, and survival rates through multiple pathways. Anemia will further attenuate the normal bone growth. The hypoxic environment regulates bone morphogenetic protein, vascular endothelial growth factor, and neuropilin-1, and affects osteoblast/osteoclast maturation and differentiation through bone metabolic changes. Hypoxia preconditioning of mesenchymal stem cells (MSCs) can enhance their paracrine effects and promote fracture healing. Concurrently, hypoxia reduces the inhibitory effect on osteocyte differentiation by inhibiting the expression of fibroblast growth factor 23. Hypoxia potentially improves bone metabolism, but it still carries potential risks. The optimal concentration and duration of hypoxia remain unclear.

CONCLUSION

There is a bidirectional relationship between renal anemia and abnormal bone metabolism. Hypoxia may improve bone metabolism but the concentration and duration of hypoxia remain unclear and need further study.

Parathyroidectomy is associated with slow progression of vascular calcification in maintenance haemodialysis patients: A propensity score-matched case-control study

Parathyroidectomy has been the mainstay of treatment of severe hyperparathyroidism in patients with kidney failure until the introduction of calcimimetic. Several large observational studies demonstrated the improvement in patient outcomes after parathyroidectomy. The benefit of parathyroidectomy on vascular calcification remains largely unexplored.

AIM

To examine the association between parathyroidectomy and the progression of vascular calcification as well as overall survival in maintenance haemodialysis patients.

METHOD

This is a matched case-control study undertaken between 2012 and 2020. Patients who underwent parathyroidectomy were identified and matched 1:1 to non-parathyroidectomized (non-PTX) haemodialysis patients using propensity score matching method resulting in 120 patients in each arm. Aortic arch calcification (AoAC) score was determined annually in the posteroanterior chest x-ray. The average follow-up period was 38 months.

RESULTS

Baseline demographic, laboratory data and AoAC score were comparable among the two groups of patients. The prevalence of AoAC was 59% in the PTX group and 54% in the non-PTX group (p = .43). Progression of AoAC occurred in 33% in the PTX group and 47% in the non-PTX group (p = .04). Multivariate generalized linear model revealed parathyroidectomy as an independent protective factor [β (95% CI) -1.04 (-1.68, -0.41)] and increased serum calcium as a potentiating factor [β (95% CI) 0.62 (0.25, 0.1)] for progression of AoAC. Linear mixed models revealed an increase in AoAC score in both groups but between group comparisons indicated substantially slower progression in the PTX group. Rapid progression of AoAC was also observed more frequently among non-PTX patients. Death occurred in 7 and 16% in the PTX and non-PTX groups, respectively. Kaplan-Meier survival curve revealed better survival associated with parathyroidectomy (p = .01). More rapid progression of AoAC also correlated with worse survival.

CONCLUSION

Parathyroidectomy was associated with slow progression of vascular calcification in maintenance haemodialysis patients.

[Risk factors affecting graft survival after parathyroidectomy and parathyroid autotransplantation in patients on maintenance hemodialysis]

OBJECTIVE

To investigate the risk factors affecting the survival of parathyroid autograft following total parathyroidectomy combined with autologous sternocleidomastoid muscle transplantation (TPTX + AT) in patients on maintenance hemodialysis (MHD) complicated with secondary hyperparathyroidism (SHPT).

OBJECTIVE

This retrospective study was conducted among the patients on maintenance hemodialysis with SHPT, who underwent successful parathyroidectomy and autotransplantation from January, 2010 to February, 2020 in our hospital. The clinical data and serum levels of calcium, phosphorus, intact parathyroid hormone, hemoglobin, and alkaline phosphatase (ALP) of the patients were collected. The enrolled patients were divided into survival group with bilateral forearm parathyroid hormone (iPTH) ratio > 1.5 and death group with a ratio < 1.5 at 2 weeks after surgery for comparison of the clinical data and perioperative indicators. The risk factors of postoperative parathyroid autograft survival were analyzed using logistic regression analysis.

OBJECTIVE

A total of 87 patients were included in the study, among whom the graft survival rate after parathyroid transplantation was 78.16%. In both groups, serum levels of calcium, phosphorus, iPTH and ALP decreased and hemoglobin level increased significantly at 1 week and 1, 2, 3, 6 and 12 months after surgery (P < 0.01). Logistic regression analysis showed that serum ALP level was an independent risk factor for graft survival following parathyroid autotransplantation [OR=1.003, 95% CI: 1.001-1.005, P=0.004].

OBJECTIVE

TPTX+AT is a safe and effective treatment for SHPT, and parathyroid autografts are less likely to survive following parathyroid transplantation in patients with high preoperative level of ALP.

Predictors of early postoperative hypocalcemia in patients with secondary hyperparathyroidism undergoing total parathyroidectomy

OBJECTIVE

To summarize the clinical features of secondary hyperparathyroidism (SHPT) in patients with chronic renal failure and to explore the predictive factors of postoperative hypocalcemia after total parathyroidectomy in these patients.

METHODS

The clinical data of 87 patients admitted to Guangdong Electric Power Hospital from May 2013 to February 2020 were reviewed. All patients underwent total parathyroid resection and sternocleidomastoid microtransplantation. Age, sex, and the serum calcium, phosphorus, alkaline phosphatase (ALP), and intact parathyroid hormone (iPTH) concentrations were analyzed as predictive factors of postoperative hypocalcemia.

RESULTS

Bone pain was the most common clinical manifestation in this study population, and all 87 patients experienced relief from their clinical symptoms after the surgical procedure. Age and the preoperative serum calcium, ALP, and iPTH concentrations were determined to be early predictive factors of postoperative hypocalcemia.

CONCLUSIONS

Age and the preoperative calcium, ALP, and iPTH concentrations are independent risk factors for postoperative hypocalcemia in patients with SHPT and renal disease who undergo total parathyroidectomy with sternocleidomastoid microtransplantation. These factors can help identify high-risk patients who can be managed by a multidisciplinary team to improve graft survival and quality of life.

Development of evocalcet for unmet needs among calcimimetic agents

INTRODUCTION

The calcium-sensing receptor is an important treatment target for secondary hyperparathyroidism (SHPT) in patients undergoing dialysis. In addition to vitamin D receptor activator, cinacalcet has recently been widely used for SHPT management, and the significant suppression of parathyroid hormone (PTH) with better control of serum calcium and phosphorus has been reported. However, low adherence and insufficient dose escalation mainly due to frequent gastrointestinal adverse events, still remain as major issues. To overcome these unmet needs, we have developed a new oral calcimimetic agent evocalcet, which has recently been approved by the Pharmaceutical Affairs Act in Japan.

AREAS COVERED

PubMed was searched from inception until April 2020 with the word evocalcet to summarize the development of this new calcimimetic agent, its pharmacokinetics, and the results of clinical trials, along with an overview of the differences among calcimimetic agents. This review also includes the management of SHPT with a focus on calcimimetics.

EXPERT OPINION

Evocalcet evoked fewer gastrointestinal-related adverse events while suppressing PTH at a lower dose than cinacalcet. These data suggest evocalcet may contribute to better adherence and sufficient dose escalation in patients with SHPT. Whether or not evocalcet improves clinical outcomes remains to be elucidated.

Emerging Association Between Parathyroid Hormone and Anemia in Hemodialysis Patients

Anemia is a common complication of chronic kidney disease (CKD). There are various causes of renal anemia such as decreased production of erythropoietin, resistance to erythropoietin, shortened survival of red blood cells, and bone marrow fibrosis. Secondary hyperparathyroidism (SHPT) is a less recognized, but potentially significant cause of renal anemia in CKD patients. Parathyroid hormone (PTH) has been regarded as a uremic toxin that has multiple adverse effects, and its elevated levels have been associated with renal anemia in hemodialysis patients. Moreover, recent clinical studies have shown that the treatment of SHPT using either vitamin D receptor activators, calcimimetics, or parathyroidectomy leads to improvement of anemia, supporting the role of PTH in renal anemia. Emerging data have also indicated the involvement of bone-derived fibroblast growth factor 23 in renal anemia. This review summarizes recent insights into the role of PTH in renal anemia and discusses the importance of treating SHPT in improving the control of renal anemia in hemodialysis patients.

Resurgence of parathyroidectomy: evidence and outcomes

PURPOSE OF REVIEW

Parathyroidectomy (PTx) is the definitive therapy for refractory secondary hyperparathyroidism (SHPT). The drastic effects of PTx on biochemical parameters of SHPT increases the possibility that this intervention will lead to a reduction in the adverse outcomes related to uncontrolled SHPT.

RECENT FINDINGS

The effect of PTx on mortality and cardiovascular outcomes among dialysis patients with severe SHPT have been evaluated in many observational studies from different regions of the world, including Asia, Europe, North America, and South America. In all but one small study, there was a significant association of PTx with lower all-cause mortality. In addition, in all studies, there was a trend in favor of PTx for cardiovascular morbidity and mortality. The effect of PTx on fractures has been evaluated in only one epidemiological study from the United States, which demonstrated a significant association of PTx and lower hip and combined fractures.

SUMMARY

Although randomized evidence is lacking, these highly consistent results may suggest a strong beneficial effect of PTx on long-term clinical outcomes and eliminate the potential concern of low parathyroid hormone after PTx.

Parathyroidectomy decreases neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios

BACKGROUND

Systemic inflammation has been implicated in complications and heightened mortality of patients with secondary hyperparathyroidism. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are widely available surrogate markers of inflammation. This study sought to delineate the changes in NLR and PLR after parathyroidectomy.

METHODS

A total of 213 patients undergoing initial parathyroidectomy from 2010 to 2015 for secondary hyperparathyroidism were identified from a prospectively maintained clinical database. Among 183 patients free of persistent or recurrent disease, follow-up NLR and PLR were available for analysis in 85 patients.

RESULTS

In the whole study population, the baseline NLR was positively correlated with male sex, total white blood cell count, height, serum phosphorus, and calcium-phosphorus product levels. The baseline PLR was positively correlated with platelet count, serum phosphorus, and calcium-phosphorus product levels and negatively associated with patient age. Postoperative parathyroid hormone levels were positively correlated with NLR and PLR at follow-up. For patients who had successful parathyroidectomy, there was a decrease in NLR (P = 0.0006), PLR (P = 0.0003), and platelet count (P = 0.033), whereas hemoglobin significantly increased (P = 0.0002) after surgery. Those with persistent or recurrent hyperparathyroidism had no change in NLR, PLR, hemoglobin, total white blood cell, or platelet count.

CONCLUSIONS

Successful parathyroidectomy is associated with a decrease in NLR and PLR. The modulatory effects of parathyroidectomy on systemic inflammation may partially explain the benefits of surgery in secondary hyperparathyroidism.

Biological and Clinical Effects of Calciprotein Particles on Chronic Kidney Disease-Mineral and Bone Disorder

Calciprotein particles (CPPs) are a new biological marker of chronic kidney disease-mineral and bone disorder (CKD-MBD). CPPs consist of phosphate, calcium, and some proteins, with phosphate being the major contributor to the level and biological activity of CPPs. Recent studies have shown the physiological and pathological significance of CPPs, including contributions to bone and mineral metabolism, and to tissue and organ impairments such as cardiovascular damage and inflammatory responses. These actions are well known as important aspects of CKD-MBD. Fibroblast growth factor 23 (FGF23), which is secreted from the bone as the phosphaturic hormone, is markedly elevated in CKD-MBD. Many clinical studies have shown significant relationships between the level of FGF23 and outcomes such as mortality, prevalence of cardiovascular disease, bone fracture, and levels of inflammatory markers. Basic and clinical studies have suggested that CPPs contribute to synthesis and secretion of FGF23. Surgical treatments such as renal transplantation and parathyroidectomy for patients with CKD-MBD suppress excess levels of phosphate, calcium, parathyroid hormone (PTH), and FGF23, which are related to the CPP level. Therefore, suppression of CPPs might also contribute to improved clinical outcomes after these treatments.

Residual renal function in chronic dialysis is not associated with reduced erythropoietin-stimulating agent dose requirements: a cross-sectional study

BACKGROUND

Anaemia is a very common problem in patients with end-stage kidney disease (ESKD) and the use of erythropoietin-stimulating agents (ESA) has revolutionised its treatment. Residual renal function (RRF) is associated with a reduction in ESA resistance and mortality in chronic dialysis. The primary aim was to establish whether RRF has an association with ESA dose requirements in ESKD patients receiving chronic dialysis.

METHODS

A single center, cross-sectional study involving 100 chronic dialysis patients was conducted from December 2015 to May 2016. Participants were divided into two groups depending on presence of RRF, which was defined as a 24-h urine sample volume of ≥ 100 ml. Erythropoietin resistance index [ERI = total weekly ESA dose (IU)/weight (kg)/haemoglobin concentration (g/dL] was used as a measure of ESA dose requirements.

RESULTS

There was no difference in ERI between those with RRF as compared to those without (9.5 versus 11.0, respectively; P = 0.45). Also, ERI did not differ between those receiving haemodialysis as compared with peritoneal dialysis (10.8 versus 10.2, respectively; P = 0.84) or in those using renin-angiotensin system (RAS) blockers as compared with no RAS blocker use (11.6 versus 9.2, respectively; P = 0.10). Lower ERI was evident for those with cystic kidney disease as compared to those with other causes of ESKD (6.9 versus 16.5, respectively; P = 0.32) although this did not reach statistical significance. Higher ERI was found in those with evidence of systemic inflammation as compared to those without (16.5 versus 9.5, respectively; P = 0.003).

CONCLUSIONS

There was no association between RRF and ESA dose requirements, irrespective of dialysis modality, RAS blocker use, primary renal disease or hyperparathyroidism.

Parathyroid Nodular Hyperplasia and Responsiveness to Drug Therapy in Renal Secondary Hyperparathyroidism: An Open Question

The goal of the pharmacological therapy in secondary hyperparathyroidism (SHPT) is to reduce serum levels of parathyroid hormone and phosphorus, to correct those of calcium and vitamin D, to arrest or reverse the parathyroid hyperplasia. However, when nodular hyperplasia or an autonomous adenoma develops, surgery may be indicated. We reviewed the literature with the aim of defining if the echographic criteria predictive of unresponsiveness of SHPT to calcitriol therapy are valid also in the cinacalcet era and if drug therapy may reverse nodular hyperplasia of parathyroid gland (PTG). The responsiveness to therapy and regression of the nodular hyperplasia of PTG remains an open question in the calcimimetic era as well as the cutoff between medical and surgical therapy. Prospective studies are needed in order to clarify if an earlier use of cinacalcet in moderate SHPT might arrest the progression of parathyroid growth and stabilize SHPT.

Effects of parathyroidectomy on bone metabolism in haemodialysis patients with secondary hyperparathyroidism

OBJECTIVE

To evaluate the outcome of bone metabolism and bone mineral density (BMD) in haemodialysis patients after parathyroidectomy (PTX).

METHODS

A total of 31 haemodialysis patients with secondary hyperparathyroidism (SHPT) were treated with PTX. BMD of lumbar spine (LS) and femoral neck (FN) was determined by dual energy X-ray absorptiometry.

RESULTS

Parathyroidectomy ledds to significant decrease of serum β-crosslaps (β-CTX), osteocalcin (OC) and procollagen type I amino-terminal propeptide (PINP) while serum sclerostin (SOST) increased after surgery. BMD was markedly improved in both LS and FN after PTX. Z-scores analysis further confirmed that PTX significantly benefited bone metabolism in haemodialysis patients, which well correlated with the improvement of serum iPTH and OC.

CONCLUSIONS

Parathyroidectomy leads to significant improvement of serum OC, PINP, β-CTX and SOST, which may beneficially modify calcium-phosphorus metabolism and BMD in haemodialysis patients with SHPT.

Management of secondary hyperparathyroidism: how and why?

Secondary hyperparathyroidism (SHPT) is a common complication in chronic kidney disease. Currently, various treatment options are available, including vitamin D receptor activators, cinacalcet hydrochloride, and parathyroidectomy. These treatment options have contributed to the successful control of SHPT, and recent clinical studies have provided evidence suggesting that effective treatment of SHPT leads to improved survival. Although bone disease is the most widely recognized consequence of SHPT and remains a major target for treatment of SHPT, there is increasing evidence that parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23), both of which are markedly elevated in SHPT, have multiple adverse effects on extraskeletal tissues. These actions may lead to the pathological development of left ventricular hypertrophy, renal anemia, immune dysfunction, inflammation, wasting, muscle atrophy, and urate accumulation. Given that treatment of SHPT leads to decreases in both PTH and FGF23, these data provide an additional rationale for treating SHPT. However, definitive evidence is still lacking, and future research should focus on whether treatment of SHPT prevents the adverse effects of PTH and FGF23.

Association of Increased Serum Leptin with Ameliorated Anemia and Malnutrition in Stage 5 Chronic Kidney Disease Patients after Parathyroidectomy

Leptin is an adipokine that regulates various metabolism, but its association with secondary hyperparathyroidism (SHPT), a clinical manifestation of chronic kidney disease-mineral and bone disorder (CKD-MBD), remains obscure. Parathyroidectomy (PTX) is recommended for severe SHPT patients. Here, the associations between circulating leptin and clinical characteristics in CKD patients were investigated. Effects of PTX on leptin production were analyzed in vivo and in vitro. Controls and CKD patients had approximate serum leptin levels in that a larger proportion of CKD patients with body mass index (BMI) <23 kg/m². Serum leptin was related to anemia, albumin, and bone metabolism disorders in CKD patients. Lower intact parathyroid hormone (PTH) was related with higher leptin in PTX patients group. Severe SHPT inhibited uremia-enhanced leptin production in 3T3-L1 adipocytes, which was attenuated after PTX. High levels of PTH were found to reduce Akt phosphorylation and leptin production in vitro but high levels of calcium and phosphorus were not. Successful PTX was found to improve anemia and malnutrition in severe SHPT patients, and this was correlated with increased circulating leptin levels via up-regulated Akt signaling in adipocytes. These findings indicated the therapeutic potential of leptin and related target pathway for improving survival and quality of life in CKD.

Systemic Diseases and Conditions Affecting Jaws

This article discusses the radiographic manifestation of jaw lesions whose etiology may be traced to underlying systemic disease. Some changes may be related to hematologic or metabolic disorders. A group of bone changes may be associated with disorders of the endocrine system. It is imperative for the clinician to compare the constantly changing and dynamic maxillofacial skeleton to the observed radiographic pathology as revealed on intraoral and extraoral imagery.

Association between serum alkaline phosphatase and primary resistance to erythropoiesis stimulating agents in chronic kidney disease: a secondary analysis of the HERO trial

BACKGROUND

Erythropoiesis stimulating agent (ESA)-resistant anemia is common in chronic kidney disease (CKD).

OBJECTIVES

To evaluate the determinants of severity of ESA resistance in patients with CKD and primary ESA-resistance.

DESIGN

Secondary analysis of a randomized controlled trial (the Handling Erythropoietin Resistance with Oxpentifylline, HERO).

SETTING AND PATIENTS

53 adult patients with CKD stage 4 or 5 and primary ESA-resistant anemia (hemoglobin ≤120 g/L, ESA resistance index [ERI] ≥1.0 IU/kg/week/gHb for erythropoietin or ≥0.005 μg/kg/week/gHb for darbepoeitin, no cause for ESA-resistance identified).

MEASUREMENTS

Iron studies, parathyroid hormone, albumin, liver enzymes, phosphate or markers of oxidative stress and inflammation.

METHODS

Participants were divided into tertiles of ERI. Multinomial logistic regression was used to analyse the determinants of ERI tertiles.

RESULTS

All patients, except one, were receiving dialysis for end-stage kidney disease. The mean ± SD ERI values in the low (n = 18), medium (n = 18) and high (n = 17) ERI tertiles were 1.4 ± 0.3, 2.3 ± 0.2 and 3.5 ± 0.8 IU/kg/week/gHb, respectively (P < 0.001). There were no significant differences observed in age, gender, ethnicity, cause of kidney disease, diabetes, iron studies, parathyroid hormone, albumin, liver enzymes, phosphate or markers of oxidative stress and inflammation between the ERI tertiles. The median [inter-quartile range] serum alkaline phosphatase concentrations in the low, medium and high ERI tertiles were 89 [64,121], 99 [76,134 and 148 [87,175] U/L, respectively (P = 0.054). There was a weak but statistically significant association between ERI and serum alkaline phosphatase (R(2) = 0.06, P = 0.03). Using multinomial logistic regression, the risk of being in the high ERI tertile relative to the low ERI tertile increased with increasing serum alkaline phosphatase levels (P = 0.02). No other variables were significantly associated with ERI.

LIMITATIONS

Small sample size; bone-specific alkaline phosphatase, other markers of bone turnover and bone biopsies not evaluated.

CONCLUSIONS

Serum alkaline phosphatase was associated with severity of ESA resistance in ESA-resistant patients with CKD. Large prospective studies are required to confirm this association. (

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry 12608000199314).

Parathyroidectomy and survival among Japanese hemodialysis patients with secondary hyperparathyroidism

Parathyroidectomy (PTx) drastically improves biochemical parameters and clinical symptoms related to severe secondary hyperparathyroidism (SHPT) but the effect of PTx on survival has not been adequately investigated. Here we analyzed data on 114,064 maintenance hemodialysis patients from a nationwide registry of the Japanese Society for Dialysis Therapy to evaluate the associations of severity of SHPT and history of PTx with 1-year all-cause and cardiovascular mortality. We then compared the mortality rate between 4428 patients who had undergone PTx and 4428 propensity score-matched patients who had not despite severe SHPT. During a 1-year follow-up, 7926 patients of the entire study population died, of whom 3607 died from cardiovascular disease. Among patients without a history of PTx, severe SHPT was associated with an increased risk for all-cause and cardiovascular mortality. However, such an increased risk of mortality was not observed among patients with a history of PTx. In the propensity score-matched analysis, patients who had undergone PTx had a 34% and 41% lower risk for all-cause and cardiovascular mortality, respectively, compared to the matched controls. The survival benefit associated with PTx was robust in several sensitivity analyses and consistent across subgroups, except for those who had persistent postoperative SHPT. Thus, successful PTx may reduce the risk for all-cause and cardiovascular mortality in hemodialysis patients with severe, uncontrolled SHPT.

Hematologic manifestations of kidney disease

Physiologically, there is an intimate link between the kidney and the blood. Many of the kidney diseases are the result of alteration in the blood such as dysproteinemia, microangiopathic hemolytic anemia (MAHA), hemolysis, etc. On the other hand, the kidney is the organ responsible for the regulation of hematopoiesis. Renal dysfunction can lead to both anemia and polycythemia. In addition, recent understanding of the MAHA process reveals that the renal microvasculature plays a key role in the pathogenesis. Finally, the failure of the kidney to clear toxins from the body can result in alteration involving hemostasis, as well as leukocyte function and survival.

The Association between Parathyroid Hormone Levels and Hemoglobin in Diabetic and Nondiabetic Participants in the National Kidney Foundation's Kidney Early Evaluation Program

BACKGROUND

Both anemia and secondary hyperparathyroidism are reflections of hormonal failure in chronic kidney disease (CKD). While the association of elevated levels of parathyroid hormone (PTH) and anemia has been studied among those with advanced CKD, less is known about this association in mild-to-moderate CKD.

METHODS

In a cross-sectional analysis, the relationship between PTH and hemoglobin levels was investigated in 10,750 participants in the National Kidney Foundation's Kidney Early Evaluation Program with an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m².

RESULTS

In the unadjusted analysis, higher PTH levels were associated with lower hemoglobin levels. However, after multivariable adjustment for age, race, gender, smoking status, education, cardiovascular disease, diabetes, hypertension, cancer, albuminuria, BMI, baseline eGFR, calcium, and phosphorus, the direction of association changed. As compared to the first PTH quintile, hemoglobin levels were 0.09 g/dl (95% CI: 0.01-0.18), 0.15 g/dl (95% CI: 0.07-0.24), 0.18 g/dl (95% CI: 0.09-0.26), and 0.13 g/dl (95% CI: 0.07-0.25) higher for the second, third, fourth, and fifth quintiles, respectively. Similarly, each standard deviation increase in natural log transformed PTH was associated with a 0.06 g/dl (95% CI: 0.03-0.09, p = 0.0003) increase in hemoglobin. However, a significant effect modification was seen for diabetes (p = 0.0003). Each standard deviation increase in natural log transformed PTH was associated with a 0.10 g/dl (95% CI: 0.054-0.138, p < 0.0001) increase in hemoglobin, while no association was seen among those without diabetes mellitus.

CONCLUSION

After multivariable adjustment, there was a small positive association between PTH and hemoglobin among diabetics but not among nondiabetics.

Mice lacking the sodium-dependent phosphate import protein, PiT1 (SLC20A1), have a severe defect in terminal erythroid differentiation and early B cell development

Phosphate is critical in multiple biological processes (phosphorylation reactions, ATP production, and DNA structure and synthesis). It remains unclear how individual cells initially sense changes in phosphate availability and the cellular consequences of these changes. PiT1 (or SLC20A1) is a constitutively expressed, high-affinity sodium-dependent phosphate import protein. In vitro data suggest that PiT1 serves a direct role in mediating cellular proliferation; its role in vivo is unclear. We have discovered that mice lacking PiT1 develop a profound underproduction anemia characterized by mild macrocytosis, dyserythropoiesis, increased apoptosis, and a near complete block in terminal erythroid differentiation. In addition, the animals are severely B cell lymphopenic because of a defect in pro-B cell development and mildly neutropenic. The phenotype is intrinsic to the hematopoietic system, is associated with a defect in cell cycle progression, and occurs in the absence of changes in serum phosphate or calcium concentrations and independently of a change in cellular phosphate uptake. The severity of the anemia and block in terminal erythroid differentiation and B cell lymphopenia are striking and suggest that PiT1 serves a fundamental and nonredundant role in murine terminal erythroid differentiation and B cell development. Intriguingly, as the anemia mimics the ineffective erythropoiesis in some low-grade human myelodysplastic syndromes, this murine model might also provide pathologic insight into these disorders.

Resistance to erythropoietin-stimulating agents: etiology, evaluation, and therapeutic considerations

Routine clinical and laboratory assessments facilitate diagnosis of erythropoietin (EPO) resistant anemia by allowing early identification of patients with non-adherence. Any new event that impairs response to EPO (e.g., catheter sepsis) must be promptly controlled. Because of the confounding interaction of its risk factors, initial evaluation should include nutrition, dialysis adequacy, hemorrhage, bone mineral metabolism, and inflammation. Prevention of EPO resistance is more cost effective and should include adequate dialysis and nutritional supplements. Blood loss during hemodialysis (HD) procedures should be minimized. If there is laboratory proof of iron deficit intravenous repletion is most effective. Oxidative stress may be attenuated by vitamins E and C, while optimal control of hyperparathyroidism will enhance EPO stimulation. Contaminated dialysates should be suspected if there is EPO-stimulating agents (ESA) resistance at the same time among most members of a dialysis program. Heavy metal toxicity should be suspected in high-risk patients. The impact of co-morbidities such as hemoglobinopathy, glucose 6 phosphate dehydrogenase (G6PD) deficiency and connective tissue diseases must be excluded in an appropriate setting. In conclusion, given the multiple risk factors of EPO resistance promotion of the overall health status will most likely yield an enduring benefit. Finally, there are experimental trials of gene-based (therapy) to stimulate endogenous EPO synthesis with the goal of avoiding the off-target effect of excessive dosing.

Normochromic normocytic anemia in a postmenopausal woman with severe osteoporosis treated with intermittent parathyroid hormone

Intermittent exogenous parathyroid hormone (PTH) is a potent osteoanabolic agent used for the treatment of severe osteoporosis. Two molecules of recombinant PTH are commercially available: the full-length PTH (PTH 1-84) and teriparatide (PTH 1-34). We present the first report of PTH-induced mild, asymptomatic, normochromic normocytic anemia in a postmenopausal woman treated sequentially with PTH 1-84 and PTH 1-34. Anemia was more pronounced with PTH 1-84 compared to PTH 1-34 and was reversed with each regimen discontinuation. We suggest monitoring of hematocrit and hemoglobin in PTH-treated patients, especially when PTH 1-84 is used.