Effect of acute citrate load on markers of bone metabolism in healthy volunteers

Association of regular plasmapheresis donation with serum protein and electrolyte levels: a multicentre cross-sectional study in China

BACKGROUND

China's plasmapheresis donation policy differs from that of Western countries. The association between regular plasmapheresis donation and donor health in China is still unknown.

OBJECTIVES

To investigate the association of regular plasmapheresis donation with serum protein and electrolyte levels and provide scientific evidence for policy improvement.

DESIGN

Multicentre cross-sectional study.

SETTING AND PARTICIPANTS

A total of 767 regular and 726 new donors from the provinces of Sichuan, Hunan, Henan and Yunnan were recruited from September 2021 to October 2022.

PRIMARY AND SECONDARY OUTCOME MEASURES

Our primary outcome focused on measuring the levels of serum protein and electrolyte levels, including total serum protein (TSP), IgG, albumin (Alb), haemoglobin (Hb), calcium, potassium (K+) and magnesium (Mg2+). The secondary outcome assessed their abnormal rates.

RESULTS

Male and female donors in the high donation frequency group (>16 donations per year) exhibited lower IgG levels compared with new donors (p=0.008 for male donors and p=0.007 for female donors). Additionally, female donors with high donation frequency and a high total number of lifetime donations (>100 donations) had significantly lower Hb concentrations than new donors. However, no significant changes were observed in TSP, Alb, calcium, K+ and Mg2+ levels. There were also no statistically significant differences in the rates of abnormal protein and electrolyte values below the respective threshold levels between new and regular donors.

CONCLUSIONS

Plasmapheresis donation is not associated with an increased risk of abnormalities in the analysed parameters. However, the results provide preliminary evidence supporting the routine inclusion of IgG screening for donors, as plasmapheresis donation is associated with a decrease in IgG levels. Particular attention should be paid to the Hb levels of female donors, especially those who donate frequently. Testing of TSP at each donation may not be necessary.

Bone Turnover Markers Changes Induced by Plateletpheresis May Be Minimized with Oral Supplementation of Calcium, Minerals, and Vitamin D before the Procedures: A Non-Randomized, Controlled Study

Apheresis allows the collection of specific blood components but changes serum calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), and hormones involved in bone metabolism due to citrate infusion. We assessed the effect of oral supplementation of calcium, vitamin D, and minerals as pills or an enriched diet before plateletpheresis donation on levels of divalent cations, hormones, and bone turnover markers that may prevent metabolic changes. Methods: Non-randomized controlled study including 134 donors. Serum parathyroid hormone (PTH), Ca, Mg, Zn, Cu, osteocalcin (OC), vitamin D, and type-1 collagen C-terminal telopeptide (CTX-1) levels were measured at baseline and post-procedure. Donors were divided into four groups: supplemented with calcium carbonate and vitamin D (cal + vitd); those receiving calcium, minerals, and vitamin D (cal + vitd + min); those receiving a calcium-rich diet (diet) and a control group (control). Results: PTH levels increased >1-fold, whereas tCa, tMg, Zn, Cu, iCa, iMg, and vitamin D levels decreased immediately after apheresis amongst donors of any group; when these levels were measured two weeks later, donors in the calcium-vitd and cal + vitd + min groups returned to basal values; donors in the cal + vitd + min group were the only group that kept their levels of OC and CTX unchanged at the different study times. Conclusions: Bone turnover markers changes induced by plateletpheresis may be minimized with oral supplementation of calcium, minerals, and vitamin D two days before the procedures.

Serial monitoring of ionised calcium levels in plateletpheresis donors: A study from tertiary care oncology centre in India

BACKGROUND

Plateletpheresis is a safe procedure, and the most common reaction is hypocalcemia which is transient and self-limiting, but it can have an impact on donor experience and donor return rate.

AIM

To serially monitor the ionized calcium levels of the plateletpheresis donors and to correlate with symptoms of hypocalcemia if any.

METHODS

It was a prospective observational study in 126 healthy voluntary donors eligible for plateletpheresis as per the Departmental SOP and after taking written informed consent. Procedures were conducted on continuous flow centrifugation (CFC) and intermittent flow centrifugation (IFC) cell separators. Donor blood samples were collected in pre-heparinized syringes at different intervals to measure ionized calcium levels (iCa++) by venous blood gas analysis (Cobas 221).

RESULTS

There was a continuous and gradual decrease in iCa++ from start to 30-45 minutes during the procedure; while the levels showed a gradual increase at end of the procedure and reached near the baseline values after 15-30 min of completion of the procedure. The change in iCa++ was statistically significant at 30 min and 45 min (p < 0.05), which was correlated with symptoms of hypocalcemia observed in 32.5 % (41/126) of the donors. Females experienced more symptoms of hypocalcemia as compared to males (p < 0.01). Donors who underwent plateletpheresis on the IFC machine experienced more symptoms of hypocalcemia as compared to the CFC machine (p < 0.05).

CONCLUSION

For donors with persistent symptoms of hypocalcemia which are unrelieved by procedural modifications (reducing blood return rate, citrate infusion rate, etc.) measurement of iCa++ and administration of oral calcium tablets may be considered.

Impact of frequent apheresis blood donation on bone density: A prospective, longitudinal, randomized, controlled trial

Background

Blood for transfusion is lifesaving and essential to many elements of modern medical practice. The global blood supply relies on volunteer blood donors. Apheresis is increasingly used to collect blood and requires anticoagulant to prevent extracorporeal coagulation. Citrate, the standard apheresis anticoagulant, chelates ionized calcium with consequent perturbations of serum calcium, parathyroid hormone, vitamin D, and markers of bone remodeling in donors. Cross-sectional studies of bone mineral density (BMD) among apheresis donors exhibit conflicting results.

Methods

The longitudinal, randomized, controlled ALTRUYST trial (NCT02655055) was undertaken to determine whether BMD declined following high frequency apheresis blood donation over 1 year. The study was powered at 80% to detect the primary outcome of a 3% decline in BMD. Subjects new to apheresis agreed to make ≥20 apheresis donations in a one-year period and were randomized to treatment (high frequency apheresis) or control (no apheresis). Dual-energy x-ray absorptiometry was performed before and after participation. Two-sided t-test and multivariable logistic regression were used to assess outcomes.

Findings

Mean lumbar spine BMD did not change during the study among control donors (−0.002 g/cm², 95%CI [−0.020, 0.016], p = 0.78), or among donors in the apheresis arm (mean change = 0.007 g/cm², 95%CI [−0.005, 0.018], p = 0.24). Mean total hip BMD did not change for control donors (mean change = 0.002 g/cm², 95%CI [−0.006, 0.009], p = 0.63) or apheresis donors (−0.004 g/cm², 95%CI [−0.10, 0.002], p = 0.16). Tests for differences in proportions of donors with change in BMD exceeding the least significant change at the lumbar spine in either a positive [8 apheresis (31%), 4 control (27%), p = 0.78] or negative direction [4 apheresis (15%), 5 control (33%)] were statistically non-significant (p = 0.18). Proportional increases [0 apheresis (0%), 1 control (7%), p = 0.18] and decreases [3 apheresis (12%), 1 control (14%)] were also not significantly different at the total hip (p = 0.61).

Interpretation

ALTRUYST is the first longitudinal trial to demonstrate that apheresis blood collection guidelines in the United States adequately protect the skeletal health of male volunteer blood donors.

Funding

Marquette University and the BloodCenter Research Foundation.

•

ALTRUYST (NCT02655055) was a prospective RCT.

•

It tested if BMD declined following high frequency apheresis blood donation.

•

High frequency apheresis blood donation did not affect lumbar spine BMD.

•

High frequency apheresis blood donation did not affect total hip BMD.

•

High frequency apheresis blood donation did not affect trabecular bone score.

No association between frequent apheresis donation and risk of fractures: a retrospective cohort analysis from Sweden

BACKGROUND

Citrate anticoagulation during apheresis induces transient alterations in calcium homeostasis. It is unknown whether the repeated, transient alterations in calcium homeostasis experienced by repeated apheresis donors affects bone turnover to increase fracture risk. Our aim was to investigate the risk of osteoporotic and nonosteoporotic fracture among voluntary, frequent apheresis donors.

STUDY DESIGN AND METHODS

All apheresis donors were identified from the Scandinavian Donations and Transfusions database (SCANDAT2), which includes information on over 1.6 million blood donors from Sweden and Denmark from the years 1968 and 1981, respectively. Only data from Sweden were used for these analyses. Information on fractures was obtained by linking SCANDAT2 to hospital registers. Poisson regression was used to compute incidence rate ratios of fractures in relation to the cumulative number of apheresis donations, both overall and in fixed time windows.

RESULTS

In total, 140,289 apheresis donors (67,970 women and 72,319 men) were identified from the SCANDAT2 database and were followed for up to 23 years. We observed no association between the frequency of apheresis donation and the risk of fracture either in the overall study period or during fixed-length time windows. The incidence rate ratio of fractures in donors who had made 100 or more cumulative apheresis donations was 0.99 (95% confidence interval, 0.92-1.06) compared with donors who had made from 9 to 24 donations. The results were similar in analyses stratified by sex and restricted to postmenopausal women.

CONCLUSIONS

The absence of an association between repeated apheresis donation and fracture risk indicates that apheresis collection is safe with regard to bone health.

Adverse events and safety issues in blood donation--a comprehensive review

Although blood donation is generally safe, a variety of risks and complications exist, the most common being iron deficiency, vasovagal reactions and citrate-related events. In the last decades, extensive efforts have significantly improved recipient and product safety, but there is still great potential to optimise donor care. Many therapies in modern medicine depend on the prompt availability of blood products, therefore it is crucial to maintain a motivated and healthy donor pool in view of a limited number of healthy volunteers willing and able to give blood or blood components. We present a comprehensive review on adverse events addressing all types of blood donation including whole blood, plasma, platelet, peripheral blood stem cell, leucocyte and bone marrow donation. In addition, we outline strategies for the prevention and treatment of these events and give a blueprint for future research in this field.

Calcium supplementation attenuates citrate-related changes in bone metabolism: a placebo-controlled crossover study in healthy volunteers

BACKGROUND

Citrate is the anticoagulation of choice in apheresis procedures. Citrate anticoagulation results in a short-term increase in serological markers of bone turnover, with uncertain clinical significance.

AIM

To understand the effect of calcium supplementation on serological bone turnover markers during an acute citrate load as a mimic of citrate anticoagulation during apheresis procedures.

METHODS

A placebo-controlled, crossover study was conducted in 22 healthy volunteers. Volunteers received a standardized citrate load at a fixed dose of 1.5 mg/kg of body weight/min for 80 min for three times and a single placebo infusion as a control. Each intervention was separated by a wash-out interval of 2 to 3 weeks. During two citrate infusions, volunteers received an additional calcium supplementation, consisting of either oral administration of calcium carbonate or an i.v. bypass infusion of calcium gluconate. Serial blood samples were collected for the determination of ionized calcium (iCa), intact parathyroid hormone (iPTH) and markers of bone remodeling, C-telopeptide of type 1 collagen (CTX) and osteocalcin (OC).

RESULTS

The infusion of citrate without calcium supplementation resulted in an increase in the bone formation marker OC and the bone resorption marker CTX, in addition to the changes in iPTH and iCa. The administration of calcium by either oral administration or as an i.v. bypass infusion attenuated the observed changes in CTX, but showed no effects on the elevation of the bone formation marker OC. There was no difference in the attenuation of CTX between the two calcium formulations. However, the i.v. application of calcium gluconate had a superior effect in reducing the change of serum iPTH and iCa as compared to the oral administration of calcium carbonate.

CONCLUSIONS

Calcium supplementation is an effective method in damping the citrate-related transient increase of the serological bone resorption marker CTX. As a mimic for the citrate-based apheresis procedure, our data may enforce the prophylactic application of calcium supplementation to attenuate the short-term elevation of bone resorption related to an acute citrate load.

Persistent hypocalcemia associated with therapeutic plasma exchange performed to reduce HLA antibody levels in cardiac transplant recipients

BACKGROUND

Patients who receive heart transplants may undergo therapeutic plasma exchange to reduce high levels of HLA antibodies which may increase the risk of allograft rejection. Plasma exchange may predispose to hypocalcemia because of chelation of calcium by sodium citrate, used as an anticoagulant both during the procedure and in thawed fresh frozen plasma often used for replacement.

METHODS

We report three adults with dilated cardiomyopathy who underwent cardiac transplantation and serial plasma exchange for high levels of HLA antibodies. We followed these patients' pre-exchange serum calcium levels and the quantity of calcium supplementation they received. Further, we examined myocardial tissue sections post-transplantation for calcium deposition.

RESULTS

Our patients' serum calcium levels were initially normal, but, despite aggressive calcium repletion, remained low (nadirs for pre-exchange ionized calcium in two patients 4.48 and 3.8mg/dL, respectively, reference range 4.6-5.4mg/dL). For patient 3, pre-exchange total calcium on day 2 was 7.9mg/dL (reference range 8.4-10.2mg/dL). Two patients had intermittent symptoms of hypocalcemia. Studies of cardiac tissue sections (available only from these two patients) were consistent with the presence of calcium deposition post transplantation. In comparison, six patients who underwent lung transplantation and plasma exchange for high levels of HLA antibodies did not manifest significant hypocalcemia.

CONCLUSIONS

We emphasize the need for prompt and sufficient calcium replacement, monitored by serum ionized calcium levels, in the early post-cardiac transplantation period when plasma exchange is performed with thawed fresh frozen plasma replacement. The persistently low serum calcium levels we observed post heart transplantation were possibly contributed to by increased myocardial calcium influx.

Changes in osteopontin and in biomarkers of bone turnover during human endotoxemia

Systemic infection and inflammation in men are associated with bone loss. Rodent studies have elucidated the pathways mediating the effects of bacterial lipopolysaccharide (LPS), activated immune cells and hormones on bone. Here we investigate the changes in biochemical parameters of bone turnover following human endotoxemia, an experimental model of self-limiting systemic infection and inflammation. Ten healthy men received in a randomised, placebo-controlled, cross-over trial once placebo and once 2 ng/kg Escherichia coli endotoxin (LPS). During the following 6 h we monitored parathyoid hormone (PTH) and osteopontin (OPN), a multifunctional protein related to bone pathophysiology, as well as biochemical markers of bone turnover: C-terminal telopeptide of type I collagen (CTX), N-terminal propeptide of type I collagen (P1NP) and osteocalcin (OC). In LPS sessions there was a transient fall in PTH at 3 h (p=0.009) and a nearly two-fold increase in OPN levels after 6 h (LPS: 155+/-19 pg/ml; placebo: 85+/-13 pg/ml, p<0.001). LPS gradually reduced CTX levels (LPS: 0.44+/-0.4 pg/ml; placebo: 0.59+/-0.06 pg/ml, p=0.003), P1NP showed a peak at 4 h (LPS: 89.9+/-14.7 pg/ml; placebo: 75+/-9.7 pg/ml, p=0.028) and circulating OC did not change. The early human response to systemic endotoxemia boosts osteopontin levels and modifies bone biomarkers, indicating a decrease in the lytic activity of osteoclasts, accompanied by an increase in the activity of immature osteoblasts. These changes might present the acute phase response of immune and bone cells to bacterial stimuli in men.