Endocrine and cytokine changes during elective surgery

Association of preoperative thyroid hormone replacement with perioperative complications after major abdominal surgery

OBJECTIVE

To determine the association between preoperative thyroid hormone replacement and complications following major abdominal surgery.

METHODS

A retrospective case series was performed of patients enrolled in the Michigan Surgical Quality Collaborative (MSQC) who underwent major abdominal surgery at an academic institution over a 10-year period. The principal explanatory variable was preoperative thyroid hormone replacement. Primary outcomes were morbidity, mortality and length of stay.

RESULTS

2700 patients were identified. On multivariate analysis correcting for established predictors of operative morbidity, patients on preoperative thyroid replacement had a 1.5- fold increased risk of serious morbidity(p ​= ​0.01), and a 1.7- fold greater risk for serious sepsis(p ​= ​0.04). Thyroid replacement was associated with longer length of stay(p ​< ​0.001). While there was a high degree of missing data for surgical approach (31.1 ​% missing data), results suggest that patients on thyroid hormone replacement were more likely to undergo an open rather than minimally invasive surgery(p ​< ​0.01). Open surgery was associated with greater risk of serious morbidity(p ​= ​0.003) and longer length of stay(p ​< ​0.001).

CONCLUSIONS

Preoperative thyroid hormone replacement independently predicts operative morbidity and length of stay following major abdominal surgery.

Endocrine-Metabolic Response in Patients Undergoing Multiple Body Contouring Surgeries After Massive Weight Loss

BACKGROUND

The endocrine-metabolic response to trauma is directly related to its magnitude, but little is known about the adverse effects of combined surgical procedures on morbidity.

OBJECTIVES

The authors sought to evaluate risk factors by measuring the endocrine-metabolic response in patients who underwent multiple body-contouring surgeries after massive weight loss.

METHODS

This prospective, randomized, interventional study included 46 massive weight loss patients who experienced a weight loss >30% of their body mass index (BMI) and were referred for body contouring surgery. Patients were randomly allocated to the control group (n = 10) or intervention group (n = 36), which in turn was divided into 3 subgroups (n = 12, each) according to BMI, surgical time, and scar length values. Blood samples were collected from all patients at different time points to assess biological stress markers.

RESULTS

Levels of IL-6 in patients in the higher ranges of BMI and operating time and with more extensive scar length were significantly higher in the immediate postoperative period compared with baseline. Concentrations of noradrenaline were significantly higher 24 hours after surgery compared with baseline only in patients in the higher range of operating time. A higher level of IL-6 at 72 hours after surgery compared with baseline was associated with more extensive scar length. Levels of other biological stress markers did not significantly differ.

CONCLUSIONS

The combination of surgical procedures did not significantly affect the concentrations of most biological stress markers. The variable of operating time most influenced increase in plasma concentrations of stress markers.

LEVEL OF EVIDENCE: 1

Slipped capital femoral epiphysis and associated hypothyroidism. A review of the literature with two classic case examples

Slipped capital femoral epiphysis (SCFE) is a relatively common hip disorder often seen in overweight, peripubertal children. Although the exact etiology is uncertain, it is generally accepted that underlying endocrinopathies play a role in the pathogenesis. Hypothyroidism is the endocrine disorder cited most commonly in association with SCFE, and patients often have no history of thyroid dysfunction at the time of presentation. Despite being a well-recognized risk factor, recommendations for screening thyroid function in patients with typical presentations of SCFE have not been deemed cost-effective; however, there is data to support screening for hypothyroidism in patients with atypical presentations of SCFE or short stature. Hypothyroidism may have a significant impact on healing and bone union after surgical management of SCFE and there is a paucity of case reports in the literature describing potential peri- and postoperative complications. We performed a systematic review of the literature of all reported cases of SCFE with associated hypothyroidism using the search terms, which demonstrated a physiologic relationship between hypothyroidism and SCFE. Two case reports of SCFE in patients with hypothyroidism and associated complications are presented with the literature review. There is a physiologic relationship between thyroid dysfunction and SCFE, and we postulate that profound hypothyroidism may contribute to delayed healing or nonunion in patients undergoing operative management. We support the recommendation to screen patients with short stature, atypical presentation of SCFE, or perisistent nonunion after surgery. In cases of hypothyroidism, we recommend thyroid hormone replacement and laboratory confirmation of return to euthyroid state prior to operative intervention.

Alterations in Thyroid Hormones Due to Increased Intraabdominal Pressure in Rats

PURPOSE

Although the effects of increased intraabdominal pressure on the abdominal organs are well known, there is a limited data regarding its effects on the thyroid hormones. The aim of this study is to investigate the changes in thyroid hormone profiles during stress endocrine response induced by increased intraabdominal pressure, which was obtained by pneumoperitoneum in rats.

MATERIALS AND METHODS

A hundred-fifty female wistar albino rats were divided into three main groups, according to intraabdominal pressure applied; Control (Group 1), (n:30), low pressure, 15 mmHg, (Groups 2 and 3), (n:60), and high intraabdominal pressure, 25 mmHg, (Groups 4 and 5), (n:60) groups. Groups 2, 3, 4, 5 were divided into three subgroups separately, according to duration of intraabdominal pressure. Rats in Groups 3 and 5 were decompressed at the end of times indicated (15th, 30th, and 45th min) and blood samples were obtained. Whereas blood samples from Groups 2 and 4 were drawn without decompression at the end of times indicated. Measurements included thyroid stimulating hormone, cortisole, vasopressin, adrenocorticotropic hormone, triiodotronin and thyroxin.

RESULT

Our study revealed that blood TSH levels reduce and free T3 and T4 levels increase in case of prolonged intraabdominal pressure increase that cause abdominal compartment syndrome. The change in blood thyroid hormone levels are encountered prominently on 30th and 45th min.

CONCLUSION

Secretion of vasopressin, adrenocorticotropic Hormone and cortisol increases with increasing intraabdominal pressure. At high pressures, thyroid stimulating hormone secretion decreases while the secretion of triiodotronin increases. The effect of this case on the clinical findings has not been fully clarified yet and it needs further studies to clarify underlying mechanism. In this perspective, the findings of this study may be used in further clinical and experimental studies.

The role of interleukin-6 and C-reactive protein in non-thyroidal illness in premature infants followed in neonatal intensive care unit

OBJECTIVE

To investigate the role of interleukin-6 (IL-6) and C-reactive protein (CRP) in non-thyroidal illness (NTI) in premature infants.

METHODS

Serum levels of IL-6 and CRP, thyroid-stimulating hormone (TSH), total thyroxine (T4), free T4 (fT4), total triiodothyronine (T3), and free T3 (fT3) were determined at the 1st, 2nd and 4th weeks of postnatal life in 148 premature infants born before 33 weeks of gestation.

RESULTS

At the 1st week, serum T3 was negatively correlated with IL-6 (r= -0.33, p= 0.001) and CRP (r= -0.17, p= 0.03). Serum T3 was negatively and more strongly correlated with IL-6 (r= -0.49, p= 0.001) and CRP (r=- 0.33, p= 0.03) at the 2nd week, at which time sepsis frequency and low T3 rates were the highest. At the 4th week, mortality rate was higher among infants with lower T3 levels.

CONCLUSIONS

High IL-6 and CRP values related to neonatal sepsis might have a significant role in the pathogenesis of NTI in premature infants.

How to manage perioperative endocrine insufficiency

Patients with endocrinopathies frequently present to the operating room. Although many of these disorders are managed on a chronic basis, patients may have acute changes in the perioperative period that, if left unrecognized, can have a negative effect on perioperative morbidity and mortality. It is imperative that anesthesiologists understand the implications of the surgical stress response on hormonal flux. This article focuses on the 4 most commonly encountered endocrinopathies: diabetes mellitus, hyperthyroidism, hypothyroidism, and adrenal insufficiency. Specific challenges pertaining to patients with pheochromocytoma are also discussed.

Surgery in the patient with endocrine dysfunction

Patients with preoperative endocrinopathies represent a particular challenge not only to anesthesiologists but also to surgeons and perioperative clinicians. The "endocrine axis" is complex and has multiple feedback loops, some of which are endocrine and paracrine related, and others that are strongly influenced by the surgical stress response. Familiarity with several of the common endocrinopathies facilitates management in the perioperative period. This article focuses on 4 of the most common endocrinopathies: diabetes mellitus, hyperthyroidism, hypothyroidism, and adrenal insufficiency. Perioperative challenges in patients presenting with pheochromocytoma are also discussed.

Surgery in the patient with endocrine dysfunction

Patients with preoperative endocrinopathies represent a particular challenge not only to anesthesiologists but also to surgeons and perioperative clinicians. The "endocrine axis" is complex and has multiple feedback loops, some of which are endocrine and paracrine related, and others that are strongly influenced by the surgical stress response. Familiarity with several of the common endocrinopathies facilitates management in the perioperative period. This article focuses on 4 of the most common endocrinopathies: diabetes mellitus, hyperthyroidism, hypothyroidism, and adrenal insufficiency. Perioperative challenges in patients presenting with pheochromocytoma are also discussed.

Effects of rehabilitation treatment on thyroid function

OBJECTIVE

The aim of the study was to evaluate the effects of an intensive rehabilitation programme on thyroid metabolism, the relationship between disability and thyroid hormone level, and the occurrence of nonthyroidal illness syndrome (NTIS) before and after rehabilitation.

DESIGN, SUBJECTS AND MEASUREMENTS

This was a clinical prospective study. Orthopaedic surgery patients (n = 82) were classified into two groups: patients in whom early active mobilization and walking were possible (walking group, WG, n = 45), and patients in whom these were not recommended (nonwalking group, NWG, n = 37). Levels of free T3 (fT3), fT4, TSH and rT3 were measured before and after surgery, and then at 1, 3, 7, 14 and 30 days from the beginning of rehabilitation. Personal, nutritional and clinical data were acquired for all patients. The Barthel Index (BI) was used to assess disability before and after rehabilitation.

RESULTS

Immediately after surgery, both groups of patients showed a significant decrease in mean fT3 concentrations and a significant increase in rT3; mean fT4 values decreased significantly only in NWG patients. Once rehabilitation had been completed, fT3 and rT3 levels returned to baseline values in WG patients. In NWG patients mean fT3 and fT4 levels continued to decrease significantly and rT3 values remained significantly high until the end of rehabilitation. NTIS occurred in 38% of the NWG patients. No significant changes in TSH levels were observed in either group. Finally, we observed a direct correlation between fT3 levels and the BI in WG patients.

CONCLUSIONS

Our data suggest that early patient mobilization and physical activity during an active and intensive rehabilitation programme induce recovery of thyroid function and avoid occurrence of NTIS.

Nonthyroidal illness syndrome and euthyroid sick syndrome in intensive care patients

This article reviews the pathophysiology of non-thyroidal illness syndrome (NTIS) and euthyroid sick syndrome (ESS), a multifactorial phenomenon characterized by suppression of thyroid hormone levels that has been described in several disease states, probably due to different causes in different patients. It also describes the laboratory values of thyroid function tests (TFTs), relevant animal studies, the association of NTIS and ESS with cardiovascular problems and sepsis, and the rationale for treatment.

Thyroid function changes and cytokine alterations following major surgery

To establish whether cytokine release is implicated in thyroid hormone changes during surgical stress we studied 36 adult patients (20 men; mean age +/- SD: 68.5 +/- 10.5 years) undergoing elective major abdominal operations. We measured tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8 and IL-10 and thyrotropin (TSH), free thyroxine (FT(4)) and triiodothyronine (T(3)) before scheduled non-emergency surgery, immediately postoperatively, on the 1st postoperative day (post-1) and on the 2nd postoperative day (post-2). TNF-alpha, IL-6 and IL-8 peaked on day post-1 whereas IL-10 peaked immediately postoperatively. Fourteen of 36 patients had low T(3) levels after surgery, indicating non-thyroidal illness (NTI). Significant negative correlations were noted among TNF-alpha, IL-6 and IL-8 against T(3) and FT(4). Cytokines are responsible, at least in part, for NTI following major operations.

Changes within the thyroid axis during the course of critical illness

This article reviews the mechanisms behind the observed changes in plasma thyroid hormone levels in the acute phase and the prolonged phase of critical illness. It focuses on the neuroendocrinology of the low triiodothyronine syndrome and on thyroid hormone metabolism by deiodination and transport.

Saving Implants BMP-2 Application in Revision Total Hip Surgery

OBJECTIVE

Besides others, there are two major problems in total hip replacement surgery which result in implant failure. First there is aseptic loosening due to a lack of implant biocompatibility or micromovements and second periimplant wear debris induced osteolysis which limits the survival rate of an implant. Regarding to recent data there are only limited therapeutic strategies to heal these bony defects without arthroplasty revision surgery. Since the investigation and characterization of adult mesenchymal stem cells (MSCs) from bone marrow, a cell and tissue engineering based therapy might be a promising solution to heal endoprosthesis associated bony defects. Moreover the application of growth factors in bone reconstructive surgery is another treatment concept to promote local bone regeneration.

PATIENT AND METHODS

We report about a 73-year old patient with a painful weight bearing and a large, wear debris induced pelvic osteolysis after total hip arthroplasty. To prevent from salvage surgical procedures and preserve bone, a healing attempted was performed by filling the critical bony defect zone with a BMP-2/MSC composit.

RESULTS

Clinical and radiological follow-ups showed a progressive bony healing of the critical size defect area without any complications. Fifteen months after application the patient is still pain free, has no limitations in daily life or sport activities.

CONCLUSION

The case embarks on a strategy of non-embryonic stem cell and growth factor application to heal bony defects at patients with total hip endoprosthesis.

The Endocrine Response to Critical Illness: Update and Implications for Emergency Medicine

This review will provide an updated overview of the neuroendocrine response to critical illness. Specifically, the current evidence for "stress steroid" administration will be examined, as well as interventional glucose control during critical illness. The emergency physician will also find relevance in the alterations of thyroid hormones that occur in the face of severe illness or trauma.

The effects of laparascopic cholecystectomy operation on C-reactive protein, hormones, and cytokines

The endocrine and immune changes associated with surgery are well documented, but the interaction between them has not been fully evaluated. We, therefore, investigated the possible effects of laparascopic cholecystectomy operation on C-reactive protein, hormones, and cytokines. Thirty-five patients were enrolled in the study (26 females and 9 males, aged 42.4 +/- 16.9 yr, who were admitted to General Surgery Clinic for laparascopic cholecystectomy). Serum C-reactive protein, cortisol, thyroid stimulating hormone, free tri-iodothyronine, free thyroxine, tumor necrosis factor-alpha, interleukin-1beta, soluble interleukin-2 receptor, interleukin-6, and interleukin-8 levels were evaluated 6 h before and after the operation. Postoperative cortisol (p=0.02), TSH (p=0.034), tumor necrosis factor-alpha (p=0.003), soluble interleukin-2 receptor (p=0.004) were found to be significantly higher than their corresponding preoperative levels. However, postoperative serum free thyroxine (p=0.011), and free tri-iodothyronine levels (p=0.001) were decreased when compared with preoperative levels, respectively. No significant difference was observed in C-reactive protein, interleukin-1beta, interleukin-6, and interleukin-8 levels. C-rective protein levels did not change in the early period of the surgical stress. Cytokine responses observed in the early period were found to be conflicting. Cortisol is an important marker of surgical stress which also has close relationship with thyroid functions.

Perioperative management of patients with hypothyroidism

Hypothyroidism is a common disorder affecting the cardiovascular, respiratory, hematopoietic, and renal organ systems--each of which is particularly germane in the management of the surgical patient. In general, treatment of recognized hypothyroidism is recommended before any surgical procedure whenever possible and euthyroidism should be documented by measurement of serum TSH as part of the preoperative evaluation. Such a strategy is likely to result in better surgical outcomes with improved morbidity and mortality. One exception to treating first with thyroid hormone is the patient with angina or coronary artery disease requiring bypass grafting, angioplasty or stenting. In this setting, preoperative thyroid hormone therapy could tax the ischemic myocardium. The coronary blood flow should be addressed first, and thyroid hormone therapy initiated afterwards. The authors have emphasized the need for caution in the interpretation of low serum thyroid hormones in sick or surgical patients because of the importance of distinguishing between hypothyroidism and the "euthyroid sick syndrome." There is no clear evidence at this point to support thyroid hormone replacement in the latter patients, and it may be potentially harmful. Rather, we hold that T3 treatment of various surgical and other patients with nonthyroidal illness should be deferred until proof of its therapeutic efficacy is demonstrated.

The response of vestibulo-ocular reflex pathways to electrical stimulation after canal plugging

The vestibulo-ocular reflex (VOR) allows clear vision during head movements by generating compensatory eye movements. Its response to horizontal rotation is reduced after one horizontal semicircular canal is plugged, but recovers partially over time. The majority of VOR interneurons contribute to the shortest VOR pathway, the so-called three-neuron arc, which includes only two synapses in the brainstem. After a semicircular canal is plugged, transmission of signals by the three-neuron arc originating from the undamaged side may be altered during recovery. We measured the oculomotor response to single current pulses delivered to the vestibular labyrinth of alert cats between 9 h and 1 month after plugging the contralateral horizontal canal. The same response was also measured after motor learning induced by continuously-worn telescopes (optically induced motor learning). Optically induced learning did not change the peak velocity of the evoked eye movement (PEEV) significantly but, after a canal plug, the PEEV increased significantly, reaching a maximum during the first few post-plug days and then decreasing. VOR gain also showed transient changes during recovery. Because the PEEV occurred early in the eye movement evoked by a current pulse, we think the observed increase in PEEV represented changes in transmission by the three-neuron arc. Sham surgery did not result in significant changes in the response to electrical stimulation or in VOR gain. Our data suggest that different pathways and processes may underlie optically induced motor learning and recovery from plugging of the semicircular canals.

Plasma proinflammatory cytokine response to surgical stress in elderly patients

We investigated the change of plasma cytokines concentrations in elderly patients during lower abdominal surgery. Plasma interleukin (IL-)6 concentrations (68.0+/-15.4 and 36.1+/-20.7 pg/ml) in elderly patients at 24 h and at 3 days after surgery were significantly higher than those (35.1+/-21.5 and 18.6+/-10.6 pg/ml) of young adults. Plasma IL-6 concentrations (92.3+/- 31.9 pg/ml) in elderly patients anesthetized with propofol and fentanyl were significantly higher at the end of the operation than that (57.9+/-36.7 pg/ml) of elderly patients anesthetized with sevoflurane and fentanyl. In conclusion, elderly patients have an increased and delayed IL-6 response to surgical trauma compared with young adults. Plasma IL-6 production after surgical trauma in elderly patients with total intravenous anesthesia with propofol was significantly higher than that in elderly patients with sevoflurane anesthesia.

Dissociation of the early decline in serum T(3) concentration and serum IL-6 rise and TNFalpha in nonthyroidal illness syndrome induced by abdominal surgery

The etiology of the prompt decline in serum T(3) in patients with nonthyroidal illness syndrome has not been adequately explained. It has been attributed to various parameters, including test artifacts, inhibitors of T(4) and T(3) binding to proteins, decreased 5'-deiodinase activity, and circulating cytokines. Currently, much attention is centered on the role of IL-6 and TNFalpha in developing the nonthyroidal illness syndrome through an effect on the hypothalamus, pituitary, and possibly 5'-deiodinase activity. We therefore studied the relation of the endogenous serum IL-6 and TNFalpha rise early in the course of nonthyroidal illness syndrome to the early decline in serum T(3) in 19 apparently healthy individuals, aged 43 +/- 16 yr, who underwent elective abdominal surgery for cholelithiasis or gastroplasty. Serum T(3), free T(3), T(4), free T(4), rT(3), TSH, IL-6, and TNFalpha were measured before and at various time intervals up to 42 h after skin incision. We observed a prompt decline in serum T(3) 30 min before skin incision, which continued to decline throughout the observational period. The magnitude of the decline reached 20% from the baseline value at 2 h. The early decline of T(3) was attenuated and lasted from the 2-8 h, probably due to the sharp increase in serum TSH that started immediately after the entrance to the operating room and lasted for 2 h. In contrast, serum T(4) and free T(4) concentrations were increased soon after skin incision and remained elevated during the first postoperative day. Serum rT(3) increased approximately 6 h after the initiation of surgery and remained elevated thereafter. Serum IL-6 remained essentially undetectable for 2 h after skin incision, whereas serum T(3) was low. Two hours after skin incision, serum IL-6 increased sharply and remained elevated throughout the observational period. Serum TNFalpha remained essentially undetectable throughout the postoperative period. Serum cortisol increased rapidly upon entrance to the operating room and remained elevated throughout the postoperative period. We conclude that the decline in serum T(3) early in the course of nonthyroidal illness syndrome is not due to increased serum IL-6 or TNFalpha levels. The brisk TSH secretion soon after the onset of the syndrome attenuates the decline in serum T(3) due to T(3) secretion from the thyroid. The early and brisk cortisol response to surgery may at least in part explain the early decrease in serum T(3) in nonthyroidal illness syndrome.

Interleukin-6 changes deformability of neutrophils and induces their sequestration in the lung

Interleukin-6 (IL-6) is an important mediator of both the hepatic and the bone marrow components of the acute-phase response. Previous studies from our laboratory have shown that cells released into the circulation from the marrow preferentially sequester in the lung. The present study was designed to examine the mechanism of this sequestration using a single dose of recombinant human IL-6 to stimulate the marrow in rabbits. Marrow release was monitored by labeling polymorphonuclear leukocyte (PMN) precursors in the marrow with the thymidine analogue, 5'-bromo-2-deoxyuridine (BrdU), 24 h before IL-6 treatment. This treatment caused a neutrophilia that was associated with the increase of circulating BrdU- labeled PMN (PMN(BrdU)) and morphometric studies confirmed that PMN(BrdU) released from the marrow preferentially sequestered in the lung microvessels compared to unlabeled PMN. IL-6 treatment increases PMN F-actin content (p < 0.05) that was not due to cell activation by IL-6. In vitro studies show that IL-6 treatment decreased the deformability of circulating PMN (p < 0.05). These studies confirm that IL-6 treatment causes an accelerated release of PMN from the bone marrow and shows that these newly released PMN have high levels of F-actin, are less deformable, and preferentially sequester in lung microvessels.

Plasma soluble interleukin-2 receptor levels during and after upper abdominal surgery

Soluble interleukin-2 (IL-2) receptor (sIL-2R) is reported to be up-regulated in inflammatory disorders. Although sIL-2R may modulate perioperative inflammatory responses, it remains unclear whether upper abdominal surgery affects plasma sIL-2R levels. We evaluated the influence of major abdominal surgery on plasma sIL-2R levels. Ten patients scheduled for upper abdominal surgery received anaesthesia with isoflurane, nitrous oxide, and epidural block. Plasma sIL-2R and IL-6 levels were determined at pre-anaesthesia, 0, 2, and 4 hours during surgery, and on postoperative days 1 (POD1) and 3 (POD3). The plasma levels of sIL-2R decreased significantly and achieved their minimum value at 4 hours (677.0 +/- 125.3 pg/ml, P < 0.01 compared to pre-anaesthesia value; 924.5 +/- 178.8 pg/ml, 95% confidence interval = 122.2-550.4). The plasma sIL-2R levels increased on POD1 (1336.5 +/- 174.0 pg/ml) and POD3 (1629.0 +/- 262.8 pg/ml), and reached a level significantly higher than the baseline (P < 0.05 and P < 0.001, 95% confidence interval = 93.4-730.6 and 402.8-1006.2, respectively). The plasma sIL-2R levels on POD3 significantly correlated with the peak IL-6 levels (r = 0.67, P < 0.05). The plasma sIL-2R levels on POD3 correlated with the amount of intraoperative bleeding (r = 0.66, P < 0.05). In conclusion, we found that major abdominal surgery induces characteristic changes in plasma soluble IL-2 receptor levels.

Interleukin-6 induces demargination of intravascular neutrophils and shortens their transit in marrow

Recombinant human interleukin-6 (IL-6) causes both a thrombocytosis and leukocytosis. The thrombocytosis is caused by an accelerating thrombocytopoiesis, but the mechanism of the leukocytosis is unknown. This study was designed to determine the relative contributions of marrow stimulation and intravascular demargination to the IL-6 induced neutrophilia. IL-6 (2 microgram/kg), administered intravenously to rabbits, caused a biphasic neutrophilia with an initial peak at 3 h and a second peak at 9 h. Using the thymidine analog 5'-bromo-2'-deoxyuridine (BrdU) to label dividing polymorphonuclear leukocytes (PMNs) in the bone marrow, we showed that IL-6 treatment mobilizes PMNs from the marginated pool into the circulating pool at 2-6 h with a decrease in L-selectin expression on PMNs and also accelerates the release of PMNs from the postmitotic pool in the bone marrow at 12-24 h. We have concluded that IL-6 causes a biphasic neutrophilia wherein the first peak results from the mobilization of PMNs into the circulating pool from the marginated pool and the second peak results from an accelerated bone marrow release of PMNs.

Dose-dependent effects of recombinant human interleukin-6 on the pituitary-testicular axis

Inflammatory cytokines are soluble mediators of immune function that also regulate intermediate metabolism and several endocrine axes. To examine the effects of interleukin-6 (IL-6), the main circulating cytokine, on the hypothalamic-pituitary-testicular axis in men, we performed dose-response studies of recombinant human IL-6 (rHuIL-6) in normal volunteers. Increasing single doses of IL-6 (0.1, 0.3, 1.0, 3.0, and 10.0 microg/kg body weight) were injected subcutaneously into 15 healthy male volunteers (3 at each dose) in the morning. We measured the circulating levels of testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and sex hormone binding globulin (SHBG) at baseline and then at 24 h, 48 h, and 7 days after the IL-6 injection. LH and FSH levels were also measured half-hourly for the first 4 h after the IL-6 injection. All IL-6 doses were tolerated well and produced no significant adverse effects. Mean peak plasma IL-6 levels achieved after IL-6 administration were 8 +/- 1, 22 +/- 5, 65 +/- 22, 290 +/- 38, and 4050 +/- 149 pg/ml, respectively for the five doses. We observed no significant changes in plasma testosterone levels after the two smaller IL-6 doses. The three higher IL-6 doses, however, caused significant decreases in testosterone levels by 24 h, which persisted at 48 h and returned to baseline by 7 days. The higher testosterone suppression was after the 3.0 microg/kg dose, making the dose-response curve bell-shaped. There also appeared to be small but not significant increases in LH levels after the three higher IL-6 doses, which were not acute and seemed to follow temporally the testosterone decreases. The concurrent plasma levels of FSH and SHBG were not appreciably affected by any IL-6 dose. In conclusion, subcutaneous IL-6 administration, which caused acute elevations in circulating IL-6 levels of a similar magnitude to those observed in severe inflammatory and noninflammatory stress, induced prolonged suppression in testosterone levels in healthy men without apparent changes in gonadotropin levels. This suggests that IL-6 might induce persistent testicular resistance to LH action or suppression of Leydig cell steroidogenesis or both, with potential adverse effects on male reproductive function.

Acute and delayed effects of a single-dose injection of interleukin-6 on thyroid function in healthy humans

Interleukin-6 (IL-6) is produced in response to inflammatory and noninflammatory stress and acts as the principal regulator of the acute-phase protein response. IL-6 stimulates the hypothalamic-pituitary-adrenal axis and may be involved in the thyroid function abnormalities observed in nonthyroidal illness (NTI). This study examined the effects of single-dose IL-6 (3 microg/kg subcutaneously [s.c.]) in healthy human subjects: 19 received IL-6 and 13 received control saline injection. The dose of IL-6 was chosen on the basis of previous studies indicating that the peak IL-6 level after injection reaches concentrations observed with major stress such as abdominal surgery. Plasma levels of thyrotropin (TSH), free thyroxine (FT4), total T4, 3,5-3'-L-triiodothyronine (T3), 3,3'-5'-L-triiodothyronine or reverse T3 (rT3), and thyroxine-binding globulin (TBG) were measured over a 4-hour period and 24 hours after IL-6 injection. Plasma TSH levels were 27% lower 240 minutes after IL-6 relative to control levels (0.93 +/- 0.10 v 1.28 +/- 0.18 mIU/mL, P = .001), but recovered by 24 hours. Plasma FT4 was elevated at 240 minutes compared with the controls (1.16 +/- 0.04 v 1.03 +/- 0.03 ng/dL, P = .0002). T4 levels were also elevated at 240 minutes (7.8 +/- 0.36 v 7.05 +/- 0.37 microg/dL, P = .0003). TBG levels were not significantly changed at this time point. At 24 hours, T3 levels were 19% lower than the control values (87.6 +/- 5.1 v 108.5 +/- 5.4 ng/dL, P = .0002); plasma rT3 levels were elevated by 21% compared with control levels (30.6 +/- 1.7 v 24.3 +/- 1.3 ng/dL, P = .002), while FT4 levels returned to normal. The changes in T3/rT3 levels were reminiscent of the pattern observed in NTI that may be due to inhibition of type-1 5'-deiodinase. Cortisol levels were greatly elevated after IL-6 compared with control values; peak levels were observed 120 minutes after IL-6 injection (28.7 +/- 1.6 v 9.5 +/- 1.0 ng/dL, P < .0001). This elevation in cortisol may have contributed to the suppression of TSH levels and inhibition of type-1 5'-deiodinase activity. Alternatively, IL-6 may have suppressed TSH secretion via a direct suprapituitary action. The elevation of T4 and FT4 levels may have been due to inhibition of T4 degradation at the liver and/or by direct action of IL-6 on the thyroid gland. These findings demonstrate the potent effects of IL-6 on thyroid hormone metabolism in healthy individuals, and suggest that IL-6 may act directly or indirectly at two or more sites on thyroid hormone secretion and metabolism.

Interleukin-10 production during and after upper abdominal surgery

STUDY OBJECTIVE

To evaluate the influence of major abdominal surgery on the plasma levels of interleukin-10 (IL-10).

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

10 ASA physical status I and II patients undergoing upper abdominal surgery.

INTERVENTIONS

All patients received combined general-epidural anesthesia with isoflurane and nitrous oxide, after insertion of an epidural catheter at T8-T9 dosed with 1.5% lidocaine.

MEASUREMENTS AND MAIN RESULTS

Plasma interleukin-6 (IL-6), interleukin-8 (IL-8), and IL-10 levels were determined with an enzyme-linked immunosorbent assay at preanesthesia, 0, 2, and 4 hours during surgery, and at the end of surgery, followed by sampling on the morning of postoperative days 1 (POD1) and 3 (POD3). Before anesthesia and at 0 hours of surgery, IL-10 was not detected. In all ten patients, the plasma levels of IL-10 showed significant elevations and achieved their maximal value 4 hours after the skin incision (p < 0.05 vs. baseline). The plasma IL-10 levels returned to preanesthesia levels on POD3. The plasma levels of IL-6 and IL-8 also increased in the perioperative period. The peak cytokine levels correlated (r = 0. 915, p = 0.0001 for IL-6 vs. IL-8; r = 0.82, p = 0.025 for IL-6 vs. IL-10; and r = 0.641, p = 0.06 for IL-8 vs. IL-10). The peak plasma IL-10 levels significantly correlated with the amount of intraoperative blood loss (r = 0.69, p < 0.05).

CONCLUSIONS

In patients undergoing major abdominal surgery, plasma IL-10 levels were elevated during and after operation. IL-10 may modulate the inflammatory responses in the perioperative period.

Dose-dependent effects of recombinant human interleukin-6 on glucose regulation

Inflammatory cytokines have metabolic actions that probably contribute to the general adaptation of the organism during infectious or inflammatory stress. To examine the effects of interleukin 6 (IL-6), the main circulating cytokine, on glucose metabolism in man, we performed dose-response studies of recombinant human IL-6 in normal volunteers. Increasing single doses of IL-6 (0.1, 0.3, 1.0, 3.0, and 10.0 mg/Kg BW) were injected sc in 15 healthy male volunteers (3 in each dose) after a 12-h fast. All IL-6 doses were tolerated well and produced no significant adverse effects. We measured the circulating levels of glucose, insulin, C-peptide, and glucagon at baseline and half-hourly over 4 h after the IL-6 injection. Mean peak plasma levels of IL-6 were achieved between 120 and 240 min and were 8, 22, 65, 290, and 4050 pg/mL, respectively, for the 5 doses. After administration of the 2 smaller IL-6 doses, we observed no significant changes in plasma glucose levels, which, because of continued fasting, decreased slightly over time. By 60 min after the 3 higher IL-6 doses, however, the decline in fasting blood glucose was arrested, and glucose levels increased in a dose-dependent fashion. The concurrent levels of plasma insulin and C-peptide were not affected by any IL-6 dose. In contrast, IL-6 caused significant increases in plasma glucagon levels, which peaked between 120 and 150 min after the IL-6 injection. In conclusion, sc IL-6 administration induced dose-dependent increases in fasting blood glucose, probably by stimulating glucagon release and other counteregulatory hormones and/or by inducing peripheral resistance to insulin action.

Elevated plasma levels of interleukin-6, interleukin-8, and granulocyte colony-stimulating factor during and after major abdominal surgery

STUDY OBJECTIVE

To evaluate the influence of major abdominal surgery on the plasma levels of inflammatory cytokines interleukin-6 (IL-6), interleukin-8 (IL-8) and granulocyte colony-stimulating factor (G-CSF).

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

10 ASA physical status I and II patients undergoing upper abdominal surgery.

INTERVENTIONS

All patients received combined general-epidural anesthesia with isoflurane and nitrous oxide, after insertion of an epidural catheter at T7-T9 dosed with 1.5% lidocaine.

MEASUREMENTS AND MAIN RESULTS

Plasma cytokine (IL-6, IL-8, G-CSF) levels were determined with an enzyme-linked immunosorbent assay (ELISA) at pre-anesthesia, 0, 2, and 4 hours during surgery, and at the end of surgery, followed by sampling on the morning of postoperative days 1 (POD1) and 3 (POD3). Plasma cortisol levels were also determined. The plasma levels of IL-6 increased gradually after skin incision and reached the maximal value at the end of surgery (p < 0.001). IL-8 levels also increased from the baseline value to their maximum at the end of surgery (p < 0.05). G-CSF levels were elevated from the pre-anesthesia value to their maximum by the end of operation (p < 0.005). Plasma cortisol levels were increased after skin incision (p < 0.001). Postoperative cytokine levels correlated significantly with each other (r = 0.68, p < 0.05 for IL-6 vs. IL-8; r = 0.81, p < 0.005 for IL-6 vs. G-CSF; and r = 0.84, p < 0.005 for IL-8 vs. G-CSF). Postoperative IL-6 levels and intraoperative blood loss correlated significantly (r = 0.64, p < 0.05).

CONCLUSIONS

These results suggest that major upper abdominal surgery stimulates the release of inflammatory cytokines presumably from the operation site. Further study is warranted to evaluate the modulation of inflammatory responses in the perioperative period.