Treatment-related fertility impairment in long-term female childhood, adolescent and young adult cancer survivors: investigating dose-effect relationships in a European case-control study (PanCareLIFE).

STUDY QUESTION: Which chemotherapeutic agents and body site-specific radiation fields are dose-dependently associated with an increased risk of fertility impairment in long-term female childhood, adolescent and young adulthood (CAYA) cancer survivors? SUMMARY ANSWER: Busulfan, lower abdominal radiotherapy (RT) and total body irradiation (TBI) seem to be associated with fertility impairment at any dose, whereas gonadotoxicity of melphalan and procarbazine is suggested at medium/high (>140 mg/m2) or high dose (>5600 mg/m2) therapy, respectively. WHAT IS KNOWN ALREADY: Several treatment-related fertility deficits, as assessed by both self-reported outcomes and hormonal markers are known to occur following treatment of CAYA cancer. However, knowledge regarding precise dose-related estimates of these treatment-related risks are scarce. STUDY DESIGN, SIZE, DURATION: The current case-control study was nested within the PanCareLIFE cohort study. In total, 1332 CAYA survivors from 8 countries, 9 institutions and 11 cohorts, participated in and contributed data to the study. PARTICIPANTS/MATERIALS, SETTING, METHODS: All participants were female 5-year CAYA cancer survivors. In total, 450 cases (fertility impaired survivors) and 882 matched controls (not fertility impaired survivors) were included. Fertility impairment was defined using both questionnaire data (primary or secondary amenorrhea; use of artificial reproductive techniques; unfulfilled wish to conceive) and hormonal data (FSH and anti-Müllerian hormone (AMH)). Multivariable logistic regression models were used to investigate the effect of (i) alkylating agent exposure, and (ii) dose categories for individual chemotherapeutic agents and for RT-exposed body sites. MAIN RESULTS AND THE ROLE OF CHANCE: A positive dose-effect relationship between cyclophosphamide equivalent dose (CED) score and fertility impairment was found, with survivors with a CED score > 7121 mg/m2 being at a significantly increased risk of fertility impairment (odds ratio (95% CI) = 2.6 (1.9-3.6) P < 0.001). Moreover, cumulative dose variables of the following treatments were significantly associated with fertility impairment: busulfan, carmustine, cyclophosphamide, melphalan, procarbazine, lower abdominal RT and TBI. Busulfan, lower abdominal RT and TBI seem to be associated with fertility impairment at any dose, whereas gonadotoxicity of melphalan and procarbazine is suggested at medium/high (>140 mg/m2) or high dose (>5600 mg/m2) therapy, respectively. LIMITATIONS, REASONS FOR CAUTION: Our study may have been subject to selection bias since data from about half of the original base cohorts were available for the current study. This could impact the generalizability of our study results. WIDER IMPLICATIONS OF THE FINDINGS: We identified survivors at high risk for fertility impairment and, consequently, for a reduced or even absent reproductive life span. Both girls and young women who are about to start anti-cancer treatment, as well as adult female survivors, should be counselled about future parenthood and referred to a reproductive specialist for fertility preservation, if desired. STUDY FUNDING/COMPETING INTEREST(S): This study has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 602030. There are no competing interests. TRIAL REGISTRATION NUMBER: n/a.

Klotho and the Growth Hormone/Insulin-Like Growth Factor 1 Axis: Novel Insights into Complex Interactions.

The growth hormone (GH)/insulin-like growth factor (IGF)-1 axis is pivotal for many metabolic functions, including proper development and growth of bones, skeletal muscles, and adipose tissue. Defects in the axis' activity during childhood result in growth abnormalities, while increased secretion of GH from the pituitary results in acromegaly. In order to keep narrow physiologic concentration, GH and IGF-1 secretion and activity are tightly regulated by hypothalamic, pituitary, endocrine, paracrine, and autocrine factors. Klotho was first discovered as an aging-suppressor gene. Mice that do not express klotho die prematurely with multiple symptoms of aging, several of them are also characteristic of decreased GH/IGF-1 axis activity. Klotho is highly expressed in the brain, the kidney, and parathyroid and pituitary glands, but can also serve as a circulating hormone by its shedding, forming soluble klotho that can be detected in blood, cerebrospinal fluid, and urine. Several lines of evidence suggest an association between klotho levels and activity of the GH/IGF-1 axis: the GH-secreting cells in the anterior pituitary of klotho-deficient mice are hypotrophic; klotho levels are altered in subjects with pathologies of the GH/IGF-1 axis; and accumulating data indicate that klotho is a direct regulator of GH secretion. Thus, klotho seems to be a new player in the intricate regulation of the GH/IGF-1 axis.

The use of continuous glucose monitoring systems in a pediatric population with type 1 diabetes mellitus in real-life settings: the AWeSoMe Study Group experience.

AIMS: The aim of the study was (a) to compare annual glycemic control in pediatric patients with type 1 diabetes mellitus (T1DM) who used a healthcare-funded continuous glucose monitoring system (RT-CGMS) to that of those who performed self-monitoring blood glucose (SMBG) only, in a real-life setting, and (b) to define parameters associated with compliance and glycemic control. METHODS: A total of 149 youth with T1DM (52.3 % females), mean age 11.8 ± 3.6 years, and 83 in the CGMS group were followed prospectively for 12 months. Glycemic control parameters and compliance to RT-CGMS were assessed periodically. RESULTS: Glycemic parameters did not differ significantly between the groups during follow-up periods. The time spent with RT-CGMS decreased and only 38 % used it for more than 75 % of the time during the 12 months (consistent users). Mean HbA1c decreased by 0.27 % in consistent users and increased by 0.21 % among intermittent users (used RT-CGMS less than 75 % of time), p = 0.013. Consistent users were younger 10. 6 ± 4.2 vs. 12.5 ± 3.6, p = 0.07, and had higher frequency of SMBG at baseline, 10.6 ± 4.9 vs. 6.3 ± 2.8, p = 0.011. CONCLUSIONS: The adoption of RT-CGMS was low, even in a healthcare system that funds its use. Caregivers should consider patient characteristics when recommending RT-CGMS use.

Androgen Receptor CAG Repeat Length in Relation to Phenotype Among Females with Nonclassical 21-Hydroxylase Deficiency.

Nonclassical 21-hydroxylase deficiency (NC21OHD) manifests with various degrees of post natal virilization. The length of CAG repeats of the androgen receptor gene (AR) is inversely correlated to activity of the human androgen receptor (AR) and affects phenotype of several androgen-dependent disorders. The aim of the study was to investigate the associations between CAG repeat length and the phenotype of females with NC21OHD. CAG repeat length and AR inactivation were assessed in females with NC21OHD, and related to their clinical presentation. CAG repeat length and AR inactivation were assessed in 119 females with NC21OHD. Biallelic mean (BAM) of the CAG repeat length and the weighted BAM (WBAM) were related to various clinical parameters. Age at diagnosis and age of menarche positively correlated with BAM (r=0.22, p=0.02, and r=0.23, p=0.01, respectively). A shorter (<25) BAM was associated with younger age at diagnosis (14.8 vs. 21.4 years, p<0.01), at adrenarche (8.1 vs. 10.2 years, p<0.01) and gonadarche (9.9 vs. 11.2 years, p<0.01), and higher corrected height standard deviation score at diagnosis (0.77 vs. 0.15, p=0.01). Precocious pubarche and precocious puberty were more frequent in these with the shorter BAM. Results of WBAM were similar. The CAG repeat length of the AR gene contributes to the clinical diversity of the phenotype in females with NC21OHD.

Postoperative adiponectin levels in pediatric patients undergoing open heart surgery.

BACKGROUND: Adipose tissue is an important endocrine organ that secretes cytokines, including adiponectin, levels of which are negatively correlated with the severity of the inflammatory process. Aim. To assess the time course of adiponectin levels following open heart surgery with cardiopulmonary bypass and its correlation with early postoperative outcomes. MATERIALS AND METHODS: Blood samples were obtained from 24 children undergoing cardiac surgery and analyzed for adiponectin, C-reactive protein, and other inflammatory markers. RESULTS: Baseline adiponectin levels were negatively correlated with patients' preoperative weight and age. Postoperative adiponectin levels decreased compared to baseline (P = 0.01) and correlated negatively with duration of cardiopulmonary bypass (r = -0.438, P = 0.037), length of stay in the pediatric intensive care unit (r = -0.457, P = 0.025), and the inotropic score (r = -0.471, P = 0.02). Adiponectin levels were positively correlated with sVCAM 1 levels; however, there was no correlation between adiponectin levels and sP selectin, tPA, MCP1, and sCD40. CONCLUSIONS: The inflammatory response after open heart surgery with cardiopulmonary bypass is associated with a reduction in adiponectin levels. Prolonged or more complicated surgery induced a more substantial inflammatory process characterized by a significant reduction in adiponectin levels over time and a delayed return to baseline levels.

Benefits of continuous subcutaneous insulin infusion (CSII) therapy in preschool children.

OBJECTIVE: The incidence of type 1 diabetes mellitus (T1DM) in young children has increased considerably over recent years. The purpose was to examine the effectiveness and safety of continuous subcutaneous insulin infusion (CSII) therapy in preschool children with T1DM. METHODS: A retrospective chart review of 113 children diagnosed with T1DM while younger than age 6 years. Mean age at diagnosis was 3.5±1.5 years and mean duration of follow 9.7±7.0 years. Patients were divided into 3 groups. Group1 initiated CSII therapy before the age of 6 years (n=26), Group 2 was treated with multiple daily injections (MDI) throughout follow-up (n=34), and Group 3 initiated CSII after age 6 (n=53). Metabolic control was assessed by HbA1C levels and safety by rates of severe hypoglycemia and diabetic ketoacidosis (DKA) events. RESULTS: In Group 1, the highest mean HbA1C value (8.5%) was observed 1-2 years prior to CSII initiation. During the 5 year period following CSII initiation, mean HbA1C levels ranged between 7.4 and 8.0%. Throughout the entire follow-up period, mean HbA1C levels were lower for Group 1 than Group 2 (p=0.05). In Group 3, mean HbA1C level decreased from 8.7% pre-CSII to 8.3% post-CSII (p<0.001). Nevertheless HbA1C levels remained higher than for those who started pump therapy before age 6 (p=0.02). CONCLUSIONS: Our study demonstrated better metabolic control in pre-school children treated with CSII compared to those treated with MDI. This benefit sustained for 5 years after CSII initiation and was not accompanied by increased risk of severe hypoglycemia or DKA events.

Type 1 diabetes in pre-school children--long-term metabolic control, associated autoimmunity and complications.

AIMS: To identify clinical characteristics and co-morbidity rates of children diagnosed with Type 1 diabetes mellitus at younger than 6 years of age. METHODS: Data were obtained from a retrospective chart review of 103 patients diagnosed with Type 1 diabetes at younger than 6 years (study group) and 220 patients at older than 6 years (comparison group). Measures of glycaemic control and occurrence of co-morbidities (coeliac disease, autoimmune thyroid disease, hypertension, nephropathy and retinopathy) were compared. RESULTS: The mean follow-up period was more than 8 years. For the study group, mean HbA(1c) levels ranged from 64 mmol/mol to 66 mmol/mol (8.0-8.2%) until age 10 years, and then rose to 73 mmol/mol (8.8%). The HbA(1c) levels were higher in the study than in the comparison group for comparable ages (P = 0.003). After adjustment for duration of diabetes this difference was not significant. The overall rate of severe hypoglycaemic events was greater in the study group than in the comparison group (P = 0.03). Kaplan-Meier diagnosis rates of celiac disease, 10 years after Type 1 diabetes diagnosis, were 14.4% and 4.2% in the study and comparison groups, respectively (P log-rank = 0.03). There were no differences in rates of autoimmune thyroid disease, hypertension, nephropathy or retinopathy. CONCLUSIONS: Children diagnosed with Type 1 diabetes before the age of 6 years were in greater risk of developing celiac disease, compared with children diagnosed after the age of 6 years. For children diagnosed with Type 1 diabetes aged under 6 years, good metabolic control was achievable until age 10 years, after which it deteriorated. Higher HbA(1c) levels observed in children diagnosed before the age of 6 years were associated with longer duration of disease.

Leptin and the post-operative inflammatory response. More insights into the correlation with the clinical course and glucocorticoid administration.

BACKGROUND: Cardiac surgery involving cardiopulmonary bypass (CPB) causes a systemic inflammatory process which can lead to multiple organ failure and postoperative morbidity. Recent animal and human studies suggested a possible involvement of leptin in the systemic inflammatory response. AIM: To characterize the response of leptin to open heart surgery (OHS) and the relationship between the time course of leptin levels and the post-operative clinical course, and to examine the effect of exogenous glucocorticoids. PATIENTS AND METHODS: Forty-seven pediatric patients, undergoing OHS for congenital heart disease were studied. Thirty-four patients (Group 1) received methylprednisolone during CPB while 13 (group 2) did not. Serial blood samples were collected perioperatively and up to 24 h after surgery, and assayed for leptin and cortisol. RESULTS: All patients' leptin levels decreased significantly during CPB (to 44-48% of baseline, p<0.001); they then increased, peaking at 12 h post-operatively. The levels of groups 1 and 2 were similar up to 8 h post-operatively; thereafter, those of group 1 were significantly higher. Recovery of leptin levels in patients with a more complicated post-operative course was comparatively slower. Cortisol levels of all patients increased significantly during CPB (p<0.001), gradually decreasing afterwards. Cortisol and leptin levels were inversely correlated in both patients' groups. CONCLUSIONS: CPB is associated with acute changes in circulating leptin levels. A complicated postoperative course is associated with lower leptin levels which are inversely correlated with cortisol levels. Leptin may participate in post-CPB inflammatory and hemodynamic responses.

Long-term neurodevelopmental outcome in conservatively treated congenital hyperinsulinism.

BACKGROUND: Congenital hyperinsulinism (CH) is treated surgically in many centers (near-total and partial pancreatectomy for diffuse and focal disease respectively). Most patients treated with near-total pancreatectomy developed diabetes during childhood/puberty. CH patients are at increased risk of neurodevelopmental disorders, some being severe, which are reported to occur in 14-44% of patients from highly heterogenous cohorts. Over the last few decades, we have treated children with CH conservatively without surgery. The aim of this study was to assess the neurodevelopmental outcome of these patients. DESIGN AND METHODS: The study included 21 Ashkenazi CH medically treated patients: 11 homozygotes (diffuse disease) and 9 heterozygotes with mutations on the paternal allele (presumed focal disease). The mean age was 13.7 years (range 8-23). Neurodevelopmental outcomes were assessed by telephone interviews of parents, using a standard questionnaire. Closest age siblings of CH patients served as controls. RESULTS: Ten CH patients had perinatal seizures of short duration. Four had post-neonatal seizures, which remitted entirely. During early childhood, four patients (19%) had hypotonia, eight (38%) had fine motor problems, seven (33%) had gross motor problems (clumsiness), and one had mild cerebral palsy. Three patients (14%) had speech problems. Eight patients required developmental therapy, compared to one in the control group. Most of these problems were resolved by age 4-5 years. At school age, all were enrolled in regular education, some excelled in their studies, 6 out of 21 patients (29%) had learning problems (2 out of 21 controls). None had overt diabetes. CONCLUSIONS: Good neurodevelopmental outcome was observed in our conservatively treated CH patients, with no diabetes as reported in patients undergoing pancreatectomy.

Peak bone mass in patients with phenylketonuria.

OBJECTIVE: Several studies have suggested a compromised bone mass in phenylketonuria patients but most reported on heterogeneous or small patient groups. Our aim was to evaluate peak bone mass in adult PKU patients and to relate BMD to nutritional parameters. PATIENTS AND METHODS: BMD was measured by dual-energy x-ray absorptiometry in 31 adult PKU patients (18 female), mean age 25 +/- 5.3 years. Nutritional intake was calculated based on food diaries. Diet adherence was determined based on patients' report. RESULTS: Mean blood phenylalanine (Phe) concentration was 968 +/- 526 micromol/L (16 +/- 8.7 mg/dl). Eight patients (32.2%) met the recommended blood Phe concentration of <726 micromol/L (<12 mg/dl), and there was no significant difference in Phe concentrations between diet-adherent and non-adherent patients. Osteopenia was detected in 11 patients (38.7%), while osteoporosis was detected in 2 patients (6.5%). No correlation was found between BMD and age, blood minerals, Phe, vitamin D and alkaline phosphatase levels, calcium and protein intake, body mass index, and body fat percentage. CONCLUSIONS: Peak bone mass is decreased in PKU patients. Possible explanations include long-standing dietary deficiency in protein, calcium, vitamin D or trace elements, or a primary defect in bone turnover inherent to the disease itself. Our data do not favour any of these hypotheses. Further studies are needed to elucidate the cause of low bone density in PKU patients.

Fiberoptic bronchoscopy and bronchoalveolar lavage for the evaluation of pulmonary disease in children with primary immunodeficiency and cancer.

BACKGROUND: Patients with childhood cancer or primary immunodeficiencies (PID) are at high risk for developing pulmonary infections and non-infectious complications. The broad differential diagnoses and the critical condition of these patients often drive physicians to start broad-spectrum antibiotic therapy before a definite diagnostic procedure is performed. A definite diagnosis may be achieved in these situations by fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL). PATIENTS AND METHODS: The records of 58 PIDs and cancer (immunocompromised group) pediatric patients who underwent 62 fiberoptic bronchoscopies between 2000 and 2004 were retrospectively reviewed and compared to 158 non-cancer patients who underwent 182 fiberoptic bronchoscopies during the same period. RESULTS: The overall diagnostic rate achieved by macroscopic inspection of purulent secretions or hemorrhage, abnormal cell count, and infectious agent isolation in the immunocompromised patients was 84%. A definite organism was recovered in 53.2% of the patients. Probable infection defined as purulent secretions or abnormal cell count without infectious agent isolation was diagnosed in another 21% of the patients. The rate of complications was 30.6%. In the control group, the overall diagnostic rate was 76.9% (n.s) and an infectious agent was demonstrated in 12.1% (P < 0.001). Probable infection was diagnosed in 24.2% (n.s) while the rate of complications was lower (15%) (P < 0.01). CONCLUSIONS: Rapid and accurate diagnoses were achieved in most procedures performed on immunocompromised patients. Although the rate of complications was higher in the immunocompromised group, they were usually very mild with no mortality. Based on these results, broncoalveolar lavage should be considered as an initial diagnostic tool in pediatric immunocompromised patients with pulmonary complications.

Circulatory neurosteroid levels in underweight female adolescent anorexia nervosa inpatients and following weight restoration.

Nineteen female adolescent inpatients diagnosed with anorexia nervosa, restricting type (AN-R) and 16 non-eating disordered (ED) controls were assessed for plasma dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulphate (DHEA-S), and cortisol levels, and for eating-related and non-eating-related psychopathology. AN-R patients were assessed at admission, 1 month and 4 months following hospitalization. The non-ED controls were assessed once. No baseline between-group differences were found in plasma cortisol, DHEA, and DHEA-S levels, whereas the patient group had a significantly lower Cortisol/DHEA-S ratio and elevated scores on most psychopathological parameters. A significant increase was found in the body mass index of the AN-R patients at 4 months post-hospitalization, accompanied by a decrease in plasma cortisol levels and a trend towards decreased Cortisol/DHEA and Cortisol/DHEA-S ratios, whereas no change occurred in psychopathology. The difference in Cortisol/DHEA-S ratio between AN-R patients and non-ED controls, and the different patterns of change in cortisol vs. DHEA(-S) levels following weight restoration, may in part account for the feeding difficulties in AN, particularly during refeeding.

Circulating leptin levels after cardiopulmonary bypass in children.

OBJECTIVE: To characterize the dynamics of circulating leptin in children after cardiac surgery with cardiopulmonary bypass (CPB), which is known to induce a systemic inflammatory response. DESIGN: Investigative study. SETTING: University-affiliated tertiary care hospital. PARTICIPANTS: Eight children (age range, 3 months to 13 years) undergoing CPB to correct congenital heart disease. INTERVENTIONS: The time courses of leptin and cortisol levels were determined. Serial blood samples were collected from the arterial catheter or from the CPB circuit preoperatively; on termination of CPB; and at 2, 4, 8, 12, 18, and 24 hours postoperatively. Plasma was recovered immediately, divided into aliquots, and frozen at -70 degrees C until use. Leptin was measured by a human leptin radioimmunoassay kit. MEASUREMENTS AND MAIN RESULTS: Leptin levels during CPB decreased to 50% of pre-CPB levels (p < 0.01). After termination of CPB, levels increased gradually and peaked at 12 hours postoperatively (10 P.M. to 1 A.M.). Cortisol levels were inversely correlated to leptin levels (p = 0.016). CONCLUSION: CPB is associated with acute changes in circulating leptin levels. These changes parallel those in cortisol, showing an inverse relationship between leptin and cortisol, suggesting a relationship between the neurobiology of these systems that could be important for the neuroendocrine response to CPB. A prognostic role of leptin and its relationship to cortisol after CPB warrant further study.

Hypopituitarism in langerhans cell histiocytosis: seven cases and literature review.

Central nervous system (CNS) involvement and, in particular, hypothalamic-pituitary involvement are well described features of Langerhans cell histiocytosis (LCH). The actual incidence of CNS-LCH disease is unknown and the natural history is poorly understood. Diabetes insipidus (DI) is reported to be the most common and well described manifestation of hypothalamic-pituitary involvement (up to 50%). Anterior pituitary dysfunction has been reported in up to 20% of patients with LCH, and occurs almost exclusively concurrently with DI. In the current paper we describe our experience with 7 patients (6 females and 1 male) in whom hypothalamicpituitary involvement was a major feature of LCH. Diagnosis was made in 4 patients during childhood or adolescence, and 3 patients were over 18 years old at the time of diagnosis. Our series exemplifies the wide spectrum of LCH-induced hypopituitarism, and demonstrates some unique features, including a higher incidence of CRH/ACTH deficiency compared to other reports (4/7 patients), and massive obesity in 2 of our patients. Endocrine function was not improved in any of our patients following medical treatment of LCH with chemotherapy and glucocorticoids. We conclude that pituitary-hypothalamic dysfunction is a common feature of LCH, and therefore all LCH patients should undergo a thorough endocrine evaluation periodically.

The effect of reduction of the peripheral fat content by liposuction-assisted lipectomy (SAL) on serum leptin levels in the postoperative period: a prospective study.

The purpose of this study was to investigate the relationship between a decrease in the peripheral fat content by suction-assisted lipectomy (SAL) and serum leptin levels. Twenty-two healthy females who underwent SAL for aesthetic reasons participated in the study. The data included height, weight, dietary habits, and leptin levels before surgery and at 1 and 6 weeks postoperatively. The aspirate ranged between 1000 and 6000 ml, with an average of 2700 ml. Thirteen patients with an aspirate of over 2700 ml all experienced an immediate postoperative decrease in appetite which returned gradually by 12 to 17 days postoperatively. They lost an average of 7% of the total body weight at 6 weeks. The leptin levels 1 week postoperatively were significantly lower than the preoperative levels (p < 0.01); at 6 weeks the decrease in leptin level was not statistically significant. In conclusion, a reduction of the peripheral fat content of more than 2700 ml by SAL has an immediate effect on leptin levels that lasts at least 1 week and correlates with voluntary changes in energy intake.

Langerhans' cell histiocytosis presenting as intracranial hypertension.

Benign intracranial hypertension is known to be associated with obesity, endocrine abnormalities, various medications, and cerebral venous sinus thrombosis. We report a patient presenting with headaches and vomiting attributed to benign intracranial hypertension. The diagnostic work-up revealed Langerhans' cell histiocytosis of the occipital bone. There was no evidence for cerebral vein thrombosis by cranial computed tomography scan, Doppler ultrasonography, planar and single photon emission computed tomography technetium 99m-labelled red blood cell scintigraphy, and magnetic resonance angiography. Excision of the occipital bone lesion and a short course of acetazolamide and prednisone were curative. We hypothesize that cytokines secreted by the tumor were responsible for the development of intracranial hypertension.

Circulating leptin and the perioperative neuroendocrinological stress response after pediatric cardiac surgery.

OBJECTIVE: Leptin may be involved in the acute stress response, regulating inflammatory parameters of major importance after cardiopulmonary bypass (CPB) surgery. Critically ill patients demonstrated significant increases in leptin levels in response to stress-related cytokines (tumor necrosis factor, interleukin [IL]-1) and abolishment of the circadian rhythm of leptin secretion. We characterized the pattern of leptin secretion in the acute postoperative period in children undergoing cardiac surgery and compared the changes in leptin levels with concomitantly occurring changes in cortisol levels, IL-8, and clinical parameters. DESIGN: Investigative study. SETTING: University-affiliated tertiary care hospital. PARTICIPANTS AND INTERVENTIONS: Twenty-nine consecutive patients, aged 6 days to 15 yrs, operated upon for the correction of congenital heart defects were studied. Surgery in 20 patients (group 1) involved conventional CPB techniques, and 9 (group 2) underwent closed-heart surgery. The time courses of leptin, cortisol, and IL-8 levels were determined. Serial blood samples were collected preoperatively, on termination of CPB, and at six time points postoperatively. Plasma was recovered immediately, aliquoted, and frozen at -70 degrees C until use. MEASUREMENTS AND MAIN RESULTS: The leptin levels in group 1 decreased during CPB to 51% of baseline (p <.001), then gradually increased, reaching 120% of baseline levels at 12-18 hrs postoperatively (p <.001), returning to baseline levels at 24 hrs (p <.01). In patients undergoing closed-heart surgery (group 2), leptin levels displayed a pattern resembling the first group: they decreased during surgery to 71% of baseline levels (p =.002) and showed a tendency to return to baseline thereafter. All group 1 patients' cortisol levels increased significantly during the first hour of surgery, then decreased, returning to baseline levels at 18-24 hrs postoperatively. There was a significant negative correlation between leptin and cortisol levels (r = -2.8, p <.01). In group 2, cortisol levels increased during and after surgery, peaking 4 hrs postoperatively and decreasing thereafter. IL-8 levels determined in 15 group 1 patients increased significantly during CPB, peaked at the end of surgery, and then decreased but remained slightly elevated even at 48 hrs postoperatively. There was a significant correlation between cortisol and IL-8 levels (r = 2.55, p <.05). Children with leukocytosis, tachycardia, and hypotension had lower leptin levels and less variation over time as opposed to those with an uncomplicated course. CONCLUSIONS: CPB is associated with acute changes in circulating leptin levels. These changes parallel those in cortisol, demonstrating an inverse relationship between leptin and cortisol. Further studies of the prognostic and therapeutic roles of leptin after CPB should be investigated.

Expression and function of insulin/insulin-like growth factor I hybrid receptors during differentiation of 3T3-L1 preadipocytes.

During the assembly of cell surface receptors, insulin proreceptors are sometimes joined to insulin-like growth factor (IGF) receptor precursors to form covalently linked hybrid receptors. To address the biological consequences of hybrid receptor formation, we studied 3T3-L1 cells known to undergo a 50-70-fold increase in insulin binding while maintaining nearly constant levels of IGF-I binding during differentiation from preadipocytes into adipocytes. The presence of insulin/IGF receptor hybrids in 3T3-L1 adipocytes was demonstrated by the immunoprecipitation of phosphorylated receptors and a novel enzyme-linked immunoassay. Hybrid receptor levels were very low in the early stages of differentiation and increased rapidly between days 4 and 6, reaching a level about 100-fold higher in the mature adipocyte. Coincident with the hybrid assembly, the formation of archetypal (alpha2,beta2) IGF receptors decreased. In fully differentiated adipocytes, virtually all of the IGF receptors were in hybrid form. Stimulation by IGF-I of receptors isolated from mature adipocytes caused autophosphorylation of IGF receptor beta subunits in hybrid complexes, whereas autophosphorylated IGF holoreceptors were not demonstrable. Insulin and IGF-I were equipotent in stimulating glucose uptake in the differentiated adipocytes, leading to the conclusion that hybrid insulin/IGF receptors can transduce a transmembrane signal when activated by IGF-I. We conclude that hybrid formation constitutes a novel post-translational mechanism whereby increased synthesis of insulin receptors limits the cell surface expression of the homologous IGF receptor. Furthermore, biological actions in 3T3-L1 adipocytes, previously attributed to archetypal IGF receptors, are in fact mediated through hybrid receptors.