Osteocalcin and the hormonal, inflammatory and metabolic response to major orthopaedic surgery

The effect of local steroid application on bony fusion in a rat posterolateral spinal arthrodesis model

INTRODUCTION

Local steroid administration during anterior cervical spine surgery has been shown to improve postoperative dysphagia. However, concerns over potential complications remain. This study aims to evaluate the effect of local steroid administration on bone regeneration and spine fusion in a preclinical model, as well as the impact on osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) in a 3D culture system.

MATERIALS AND METHODS

Forty-five rats underwent bilateral L4-L5 posterolateral lumbar fusion (PLF) utilizing local delivery of low-dose recombinant human bone morphogenetic protein-2 (rhBMP-2; 0.5 μg/implant). Rats were divided into three groups: no steroid (control), low dose (0.5 mg/kg), and high dose (2.5 mg/kg) of triamcinolone. Bone growth and fusion were assessed using radiography, blinded manual palpation, and micro-CT analysis and were visualized by histology. The impact of triamcinolone exposure on osteogenic differentiation of hBM-MSCs was evaluated by gene expression analysis, alkaline phosphatase activity assay, and alizarin red staining.

RESULTS

No significant differences in fusion scores or rates were seen in the low- or high-dose steroid treatment groups relative to untreated controls. Quantification of new bone formation via micro-CT imaging revealed no significant between-group differences in the volume of newly regenerated bone. Triamcinolone also had no negative impact on pro-osteogenic gene transcript levels, and ALP activity was enhanced in the presence of triamcinolone. Mineral deposition appeared comparable in cultures grown with and without triamcinolone.

CONCLUSIONS

Local steroid application does not seem to inhibit rhBMP-2-mediated spine fusion in rats, though our study may not be adequately powered to detect differences in fusion as measured by manual palpation or bone volume as measured by micro-CT. These findings suggest that local triamcinolone may not increase pseudarthrosis in spine fusion procedures. Further large animal and clinical studies to verify its safety and efficacy are warranted.

Glucose transporter 4 mediates LPS-induced IL-6 production in osteoblasts under high glucose conditions

PURPOSE

Diabetes causes hyperglycemic disorders due to insufficient activity of insulin, and it also increases blood glucose level. Recent studies have reported the relationship between diabetes and periodontal disease. Periodontitis is advanced by inflammatory cytokines stimulated with LPS. The purpose of this study was to investigate the effects of hyperglycemia on the expression of inflammatory cytokines induced by LPS in osteoblasts.

METHODS

Cells were cultured for 7 and 14 days in the presence or absence of LPS and glucose. The expression mRNA level of IL-6, RANKL and OCN was determined using real-time PCR. The protein expression of IL-6 and RANKL was also measured using ELISA.

RESULTS

LPS and glucose increased the mRNA expression of IL-6, coupled with a decrease in the mRNA expression of OCN, which is associated with IL-6 and glucose. It also increased the protein expression of IL-6 compared to LPS. However, LPS+Glucose did not affect the mRNA and protein expression of RANKL. Furthermore, GLUT4 inhibitor, WZB117, blocked the stimulatory effect of glucose on LPS-induced IL-6 mRNA expression. WZB117 did not affect LPS-reduced OCN mRNA expression.

CONCLUSION

These results suggest that high glucose levels increase LPS-induced IL-6 expression mediated by GLUT4.

Nerve blocks or no nerve blocks for pain control after elective hip replacement (arthroplasty) surgery in adults

BACKGROUND

It is estimated that over 300,000 total hip replacements are performed each year in the USA. For European countries, the number of hip replacement procedures per 100,000 people performed in 2007 varied from less than 50 to over 250. To facilitate postoperative rehabilitation, pain must be adequately treated. Peripheral nerve blocks and neuraxial blocks have been proposed to replace or supplement systemic analgesia.

OBJECTIVES

We aimed to compare the relative effects (benefits and harms) of the different nerve blocks that may be used to relieve pain after elective hip replacement in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 12, 2016), MEDLINE (Ovid SP) (1946 to December Week 49, 2016), Embase (Ovid SP) (1980 to December week 49, 2016), CINAHL (EBSCO host) (1982 to 6 December 2016), ISI Web of Science (1973 to 6 December 2016), Scopus (from inception to December 2016), trials registers, and relevant web sites.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) performed in adults undergoing elective primary hip replacement and comparing peripheral nerve blocks to any other pain treatment modality. We applied no language or publication status restrictions.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two review authors. We contacted study authors.

MAIN RESULTS

We included 51 RCTs with 2793 participants; of these 45 RCTs (2491 participants: peripheral nerve block = 1288; comparators = 1203) were included in meta-analyses. There are 11 ongoing studies and three awaiting classification.Compared to systemic analgesia alone, peripheral nerve blocks reduced: pain at rest on arrival in the postoperative care unit (SMD -1.12, 95% CI -1.67 to -0.56; 9 trials, 429 participants; equivalent to 3.2 on 0 to 10 scale; moderate-quality evidence); risk of acute confusional status: risk ratio (RR) 0.10 95% CI 0.02 to 0.54; 1 trial, 225 participants; number needed to treat for additional benefit (NNTB) 12, 95% CI 11 to 22; very low-quality evidence); pruritus (RR 0.16, 95% CI 0.04 to 0.70; 2 trials, 259 participants for continuous peripheral nerve blocks; NNTB 4 (95% CI 4 to 8); very low-quality evidence); hospital length of stay (SMD -0.75, 95% CI -1.02 to -0.48; very low-quality evidence; 2 trials, 249 participants; equivalent to 0.75 day). Participant satisfaction increased (SMD 0.67, 95% CI 0.45 to 0.89; low-quality evidence; 5 trials, 363 participants; equivalent to 2.4 on 0 to 10 scale). We did not find a difference for the number of participants walking on postoperative day one (very low-quality evidence). Two nerve block-related complications were reported: one local haematoma and one delayed persistent paresis.Compared to neuraxial blocks, peripheral nerve blocks reduced the risk of pruritus (RR 0.33, 95% CI 0.19 to 0.58; 6 trials, 299 participants; moderate-quality evidence; NNTB 6 (95% CI 5 to 9). We did not find a difference for pain at rest on arrival in the postoperative care unit (moderate-quality evidence); number of nerve block-related complications (low-quality evidence); acute confusional status (very low-quality evidence); hospital length of stay (low quality-evidence); time to first walk (low-quality evidence); or participant satisfaction (high-quality evidence).We found that peripheral nerve blocks provide better pain control compared to systemic analgesia with no major differences between peripheral nerve blocks and neuraxial blocks. We also found that peripheral nerve blocks may be associated with reduced risk of postoperative acute confusional state and a modest reduction in hospital length of stay that could be meaningful in terms of cost reduction considering the increasing numbers of procedures performed annually.

AUTHORS' CONCLUSIONS

Compared to systemic analgesia alone, there is moderate-quality evidence that peripheral nerve blocks reduce postoperative pain, low-quality evidence that patient satisfaction is increased and very low-quality evidence for reductions in acute confusional status, pruritus and hospital length of stay .We found moderate-quality evidence that peripheral nerve blocks reduce pruritus compared with neuraxial blocks.The 11 ongoing studies, once completed, and the three studies awaiting classification may alter the conclusions of the review once assessed.

Osteocalcin, but not deoxypyridinoline, increases in response to isoflurane-induced anaesthesia in young female guinea pigs

The effect of the inhaled anaesthetic isoflurane was investigated on bone biomarkers, both during maturation and on minerals and glucose postpartum. Female guinea pigs (n = 10) were anaesthetized during maturation (5 and 9 weeks) and postpartum (26 weeks of age) with isoflurane during dual-energy X-ray absorptiometry scanning. Blood collection was performed at all ages before and after anaesthesia for measurement of plasma osteocalcin (OC), total deoxypyridinoline (tDPD), and cortisol. Postpartum measurements also included: blood ions, acid-base parameters and glucose, plasma minerals, total alkaline phosphatase (tALP), and albumin. Plasma OC concentration almost doubled after exposure to isoflurane at 5 weeks (30.1 ± 5.0-57.9 ± 11.2 nmol/L, p < 0.001) and at 9 weeks (29.1 ± 7.5-62.9 ± 15.9 nmol/L, p < 0.001), but did not change postpartum (3.7 ± 3.3-4.3 ± 3.9 nmol/L, p = 0.88). There was no effect of isoflurane exposure on plasma tDPD at any age. Plasma cortisol increased after exposure to isoflurane at 9 weeks (1859.6 ± 383.2-2748.0 ± 235.3 nmol/L, p < 0.01) and postpartum (3376.7 ± 322.2-4091.6 ± 195.6 nmol/L, p < 0.001) but not at 5 weeks (2088.3 ± 326.4-2464.1 ± 538.0 nmol/L, p > 0.05). Blood ionized Ca(2+), Na(+) and plasma total Ca did not change, whereas plasma albumin decreased, and inorganic phosphate (PO4) and Cl(-) increased upon exposure to isoflurane. Isoflurane decreased tALP (43.2 ± 6.6-40.2 ± 5.9 IU/L, p = 0.01) and increased glucose (7.5 ± 0.6-10.9 ± 1.7 mmol/L, p < 0.0001) postpartum. Isoflurane inflates the assessment of a bone-derived biomarker, OC, during rapid growth, but not following pregnancy when formation is very low. Measurements prior to anaesthesia are recommended to reflect normal metabolism.

Comparison of the Effects of Remifentanil and Dexmedetomidine Infusions on Hemodynamic Parameters and Thyroid Hormones

OBJECTIVE

In this study, we compared the effects of remifentanil and dexmedetomidine on hemodynamic parameters, inhalation agent consumption and thyroid hormone levels at the late postoperative period.

METHODS

Forty-five euthyroid ASA I-II patients between 20 and 75 years of age were randomly assigned into three groups: During induction, Group R received 1.0 mcg kg(-1) remifentanil as slow bolus in two minutes,Group D received 1.0 mcg kg(-1) dexmedetomidine in 10 minutes as infusion,Group C received 1.0 mcg kg(-1) fentanyl as bolus. Afterwards, all patients received 2.0 mg kg(-1) propofol and 0.2 mg kg(-1) cisatracurium for induction.For anaesthesia maintenance during and up to 15 minutes before the end of the surgery; Group R received 0.05 mcg kg(-1) min(-1) remifentanil,Group D received 0.5 mcg kg(-1) h(-1) dexmedetomidine infusion.During the surgery, heart rate, mean arterial pressure and end-tidal sevoflurane concentrations were recorded for every patient. Venous blood samples were taken after the operation, at postoperative 24(th) hour and postoperative 5(th) day and the variations in fT3, fT4, TSH levels were analyzed.

RESULTS

Mean arterial pressure values and sevoflurane consumption were lower in Group R and Group D in comparison with the control group. In comparison between groups, the decrease in fT3 values at postoperative 24(th) hour was more significant in the control group than the other two groups.

CONCLUSION

We suggest that, both agents suppress the hemodynamic response, decrease the consumption of inhalation agents and cause less change in the levels of thyroid hormones, which can be considered as one of the indicators of endocrine response.

Differential effects of propofol and isoflurane on the activation of T-helper cells in lung cancer patients

It is suggested that activation and differentiation of T-helper cells are required for peri-operative anti-tumor and anti-infection immunity. The present study aimed to evaluate whether propofol stimulates the activation and differentiation of these cells in patients undergoing pulmonary lobectomy for non-small-cell lung cancer. Thirty patients were randomly allocated to receive propofol or isoflurane throughout surgery. The CD4(+)CD28(+) percentage (p < 0.0001) and the ratio of interferon-gamma:interleukin-4 (p = 0.001) all increased with propofol but showed no change with isoflurane. In contrast, cortisol increased with isoflurane (p < 0.0001) but not with propofol over time (p = 0.06). We conclude that propofol promotes activation and differentiation of peripheral T-helper cells.

Ethanol and stress activate catecholamine synthesis in the adrenal: effects on bone

Ethanol consumption and mental stress activate the sympathetic nervous system, which can adversely affect bone. We compared six groups of 10 young adult rats, three with and three without 2 h daily restraint stress. Two groups consumed food and water ad libitum, two received food and 6% (w/v) ethanol as drinking water, and two received the amount of food consumed by ethanol rats the previous day plus water ad libitum (pairfed). After 6 weeks, rats were killed. Plasma, femurs, lumbar vertebrae, and adrenals were harvested. Femoral dimensions were measured and biomechanical properties were tested by three-point bending. Plasma osteocalcin, vertebral osteocalcin mRNA levels, and adrenomedullary tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), and phenylethanolamine N-methyl transferase (PNMT) mRNA levels were quantified. Daily restraint decreased weight gain and femoral length compared to dietary controls, and appeared to partially preserve bone strength, especially in calorie-restricted pairfed rats. Femoral strength was significantly affected by treatment in that bones of pairfed controls were weakest, ethanol drinkers were intermediate, and ad libitum restrained were strongest. Femoral yield load, displacement, and work at yield load were negatively correlated with TH and DBH mRNA levels, but not PNMT, suggesting a negative influence of norepinephrine. Plasma osteocalcin and dry weight of lumbar 3-5 vertebrae were unaffected; however, osteocalcin mRNA in second lumbar vertebrae was positively correlated with TH, DBH, and PNMT levels. Ethanol consumption at this level had little effect on femur morphology or strength. In contrast, the data suggested possible stimulation rather than inhibition of vertebral bone formation.

Differing effects of acute and chronic stressors on plasma osteocalcin and leptin in rats

Stressor activation of the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis can have profound effects on bone and also appetite and metabolism. We tested in rats the response of plasma osteocalcin (pOC, a bone biomarker that is acutely stress responsive), corticosterone, and leptin to (1) ethanol consumption (5% w/v) in a liquid diet (compared with ad libitum and pair-fed rats), (2) acute restraint, and (3) acute (once, 1 h) and (4) chronic (1 h/day for 7 weeks) social aggression. Basal pOC concentration did not differ with ethanol diet or social interaction, but was elevated by both foot restraint immobilization (Imo) and restraint in wire mesh cylinders (WMR). As previously reported for chronic Imo, ingestion of ethanol blunted the pOC response to Imo. Plasma corticosterone concentration was increased by acute WMR and acute social interaction but was unaltered by chronic social interaction. Plasma leptin concentration was markedly increased by Imo in ad libitum fed, but only slightly in ethanol or pair-fed rats. In contrast, the data reflect significant differences between acute and chronic stressor effects since chronic social stress had little effect on pOC or plasma corticosterone, but tended to decrease leptin level in relation to dominance. Lack of significant impact of prolonged ethanol intake or social aggression suggests physiological adaptation.

Factors other than glucocorticoids are involved in the osteoblast activity decrease caused by tissue injury

OBJECTIVE

Serum osteocalcin is a marker of bone formation. The concentration of osteocalcin is decreased with tissue injury. As glucocorticoids are known both to be increased in this situation and to diminish serum osteocalcin, we have hypothesized that they could be involved in this decrease.

DESIGN AND PATIENTS

We compared osteocalcin levels in two groups of patients undergoing abdominal surgery, one receiving thiopental, and the other etomidate, a glucocorticoid synthesis blocker. For comparative reasons, another protein decreased by glucocorticoids (osteoprotegerin) was measured in patients anaesthetized with thiopental.

MEASUREMENTS

Serum osteocalcin, cortisol and albumin were determined before and over the 24 h following surgery. Serum concentration of osteoprotegerin (OPG) and receptor activator of the nuclear factor kappaB ligand (RANKL) were also determined before and 24 h after surgery in a third group of nine patients who received thiopental for anaesthetic induction.

RESULTS

Cortisol levels were increased in the thiopental group, whereas, as expected, were decreased in etomidate patients. However, serum osteocalcin concentration decreased in a similar way in both groups. Serum OPG and RANKL levels were within the normal range at baseline and did not significantly change after surgery.

CONCLUSIONS

The decrease in serum osteocalcin induced by tissue injury is independent of the increase in cortisol secretion triggered by the latter. In addition, another pharmacologically proven effect of cortisol on bone metabolism, OPG inhibition, could not be demonstrated in the first 24 h following surgery, in spite of the physiological increase in endogenous cortisol secretion taking place in this period.

Changes of the biochemical markers of bone turnover and periprosthetic bone remodeling after cemented hip arthroplasty

Do periprosthetic bone loss and postoperative levels of the biochemical markers of bone turnover correlate? The femoral bone mineral density of 53 patients was measured by dual-energy x-ray absorptiometry 1 week and 2, 4, 6, and 12 months after cemented total hip arthroplasty (THA). Biochemical markers of bone turnover were assayed preoperatively and 3, 8, 16, and 24 weeks post-THA. Greatest bone loss was detected in the calcar region (region of interest 7), on average, 16% after 1 year. A marker of bone resorption, C-terminal telopeptides of type I collagen, increased 21% 3 weeks after THA. A significant correlation between periprosthetic bone loss in region of interest 7 after 1 year and type I collagen at 3 weeks was seen (r = -0.42, P = .003). Data suggest that periprosthetic bone loss is induced by an early postoperative high activity of osteoclasts. Counteracting this osteoclast activity with a limited and timely postoperative antiresorptive treatment may be concluded for clinical application.

Should we use etomidate as an induction agent for endotracheal intubation in patients with septic shock?: a critical appraisal

Etomidate is commonly used for the facilitation of endotracheal intubation. While etomidate possesses multiple qualities that are beneficial in hemodynamically unstable patients who require a sedative or amnestic, its potential to negatively impact corticosteroid production is well-documented. Given the frequency of relative adrenal insufficiency observed in the critically ill and the increasing use of corticosteroids in patients with septic shock, an appraisal of the status of etomidate as an induction agent in patients with evolving or established septic shock is indicated. A review of the relevant literature suggests that its use in this setting may be harmful. It is proposed that, pending the performance of a randomized, controlled clinical trial, considerable caution should accompany its administration in patients with evolving or established septic shock. The potential role for concomitant empiric steroid replacement and the comparability of alternative induction regimens are also discussed.

The hormonal and inflammatory responses to pelvic reconstructive surgery following major trauma

Patients undergoing trauma sustain an initial injury followed by further physiological challenges during surgery. Plasma osteocalcin (OC), a marker of osteoblastic activity, declines after major surgery. Increased cortisol secretion, and other components of the perioperative stress response, may play a role in mediating this response. We have examined the osteocalcin, hormonal and cytokine responses in twenty patients undergoing post-traumatic pelvic reconstruction surgery. We measured plasma osteocalcin, serum cortisol, bone specific alkaline phosphatase (BSAP), IL-6, IL-8, IL-10, plasma epinephrine and norepinephrine concentrations for up to 3 days after surgery. We recorded an increase in IL-6, IL-10 and epinephrine concentrations perioperatively and a fall in OC and BSAP concentrations. There were no significant changes in cortisol or IL-8 concentrations. Patients undergoing pelvic reconstruction surgery following trauma have a preserved inflammatory and catecholamine response but the cortisol response may be obtunded. Osteocalcin concentrations are affected by factors other than glucocorticoids.

The effects of remifentanil and alfentanil-based total intravenous anesthesia (TIVA) on the endocrine response to abdominal hysterectomy

STUDY OBJECTIVE

To compare the effects of remifentanil with alfentanil as a part of total intravenous anesthesia (TIVA) on plasma concentrations of cortisol, insulin, and glucose, and hemodynamic responses in patients undergoing abdominal hysterectomy.

DESIGN

Randomized, double-blind study.

SETTING

University hospital.

PATIENTS

24 ASA physical status I female patients scheduled for abdominal hysterectomy.

INTERVENTIONS

Premedicated patients were randomly allocated to receive either remifentanil-propofol (Group R) or alfentanil-propofol (Group A). The loading dose of the study drug was administered over 60 seconds (remifentanil l microg kg(-l) or alfentanil 10 microg kg(-l)) followed by a continuous infusion (remifentanil 0.2 microg kg(-l) min(-l) or alfentanil 0.5 microg kg(-l) min(-l)). In both groups, propofol was administered until loss of consciousness and maintained with a propofol infusion rate of 100 microg kg(-l) min(-l). After induction of anesthesia, all patients were manually ventilated by mask with O2-air mixture for 20 minutes. Then rocuronium 0.6 mg kg(-l) was given for tracheal intubation.

MEASUREMENTS

Mean arterial pressure (MAP) and heart rate (HR) were recorded. Plasma concentrations of cortisol, insulin, and glucose were measured during anesthesia and in the recovery room.

MAIN RESULTS

In Group R, MAP and HR were lower after tracheal intubation and skin incision than in Group A (p < 0.05). Plasma cortisol concentrations decreased from baseline values at 20 minutes after induction, after tracheal intubation, and skin incision in Group R (p < 0.001). Plasma concentrations of cortisol and glucose increased from baseline values at 30 minutes after skin incision and continued to increase in both groups (p = 0.001). Plasma concentrations of cortisol, insulin, and glucose did not differ between groups at all sampling times.

CONCLUSION

Remifentanil provided better hemodynamic stability than alfentanil during anesthesia and surgery. However, both remifentanil and alfentanil had similar effects on the stress endocrine response to abdominal hysterectomy.