[Diagnostics and treatment of acromegaly : Necessity for targeted monitoring of comorbidities]

Acromegaly is a rare and severe condition, presenting with typical signs and symptoms. The diagnosis is often initially made years after the first manifestations of the disease. In more than 99% of patients the disease is caused by a benign pituitary tumor that secretes growth hormone (GH). The diagnosis is based on the presence of increased insulin-like growth factor 1 (IGF-1) levels and a lack of GH suppression in the oral glucose tolerance test. The standard imaging procedure for tumor detection is magnetic resonance imaging in the region of the sella turcica. Treatment includes surgical, drug and radiation therapy. Important factors are an intensive aftercare of the patient, controls for detection of tumor recurrence and pituitary insufficiency as well as assessment of various organ functions and risk constellations. Patient care should involve close cooperation between endocrinologists, neurosurgeons and general practitioners as well as other specialist disciplines.

Norepinephrine and corticosterone in the medial prefrontal cortex and hippocampus predict PTSD-like symptoms in mice

This study measured changes in brain extracellular norepinephrine (NE) and free corticosterone (CORT) levels in a mouse model of post-traumatic stress disorder and related them to hyperarousal and fear memory retention. To this end, microdialysis in the medial prefrontal cortex (mPFC) and the hippocampus (HPC) of male C57BL/6NCrl mice was performed during an acoustic startle response (ASR) and following an electric foot shock (FS), as well as during an ASR and recall of contextual fear (CF) 1 day later. Changes in ASR-stimulated NE levels in the mPFC corresponded to ASR 34 days after FS. Changes in basal and ASR-stimulated extracellular NE levels in the HPC, in contrast, were related to expression of early (day 2) and late (day 34) CF after FS. The increase in extracellular NE levels correlated in a U-shape manner with arousal levels and CF, thus suggesting a non-direct relationship. Stress of different modalities/strength (ASR, FS and CF) caused a similar relative increase in free CORT levels both in the mPFC and the HPC. One day after FS, ASR-induced increases in the CORT content in the mPFC tended to correlate with the FS-potentiated ASR in a U-shape manner. Taken together, these data show that the intracerebral increase in free CORT was likely related to an immediate response to stress, whereas NE neurotransmission in the forebrain predicted arousal and CF 1 month after trauma.

The glucose-dependent insulinotropic polypeptide receptor is overexpressed amongst GNAS1 mutation-negative somatotropinomas and drives growth hormone (GH)-promoter activity in GH3 cells

Somatic mutations in the GNAS1 gene, encoding the α-subunit of the heterotrimeric stimulatory G protein (Gαs), occur in approximately 40% of growth hormone (GH)-secreting pituitary tumours. By altering the adenylate cyclase-cAMP-protein kinase A pathway, they unequivocally give somatotroph cells a growth advantage. Hence, the pathogenesis of somatotropinomas could be linked to anomalies in receptors coupled to the cAMP second-messenger cascade. Among them, the glucose-dependent insulinotropic polypeptide receptor (GIPR) is already known to play a primary role in the impaired cAMP-dependent cortisol secretion in patients affected by food-dependent Cushing's syndrome. In the present study, 43 somatotropinomas and 12 normal pituitary glands were investigated for GIPR expression by quantitative reverse transcriptase-polymerase chain reaction, western blotting and immunohistochemistry. Tumoural specimens were also evaluated for GNAS1 mutational status. The effect of GIPR overexpression on cAMP levels and GH transcription was evaluated in an in vitro model of somatotropinomas, the GH-secreting pituitary cell line GH3. GIPR was expressed at higher levels compared to normal pituitaries in 13 GNAS1 mutation-negative somatotropinomas. GIP stimulated adenylyl cyclase and GH-promoter activity in GIPR-transfected GH3 cells, confirming a correct coupling of GIPR to Gαs. In a proportion of acromegalic patients, GIPR overexpression appeared to be associated with a paradoxical increase in GH after an oral glucose tolerance test. Whether GIPR overexpression in acromegalic patients may be associated with this paradoxical response or more generally involved in the pathogenesis of acromegaly, as suggested by the mutually exclusive high GIPR levels and GNAS1 mutations, remains an open question.

Evaluation of health-related quality of life in patients with Cushing's syndrome with a new questionnaire

Chronic exposure to hypercortisolism has significant impact on patient's health and health-related quality of life (HRQoL), as demonstrated with generic questionnaires. We have developed a disease-generated questionnaire to evaluate HRQoL in patients with Cushing's syndrome (CS; CushingQoL).

OBJECTIVE

Validate the CushingQoL questionnaire in patients with CS in clinical practice conditions.

DESIGN

Observational, international, cross-sectional study.

METHODS

A total of 125 patients were recruited by 14 investigators from Spain, France, Germany, The Netherlands, and Italy over a 2-month period. Clinical and hormonal data were collected and correlated with results of the generic short form 36 (SF-36) questionnaire, a question on self-perceived general health status and the CushingQoL score.

RESULTS

A total of 107 patients were pituitary-dependent and 18 adrenal-dependent CS; 104 (83%) were females, mean age 45 years (range 20-73 years); 39 (31%) were currently hypercortisolemic; and 47 (38%) adrenal insufficient. In clinical practice, CushingQoL was feasible (117; 94% of patients fully responded to the questionnaire in a mean time of 4 min), reliable (Crohnbach's alpha=0.87), and valid (factorial analysis demonstrated unidimensionality and Rasch analysis lead to a final version with 12 items). A significant (P<0.001) correlation was observed between CushingQoL score and patients self-perceived general health status and dimensions of SF-36 (Pearson's correlation coefficient > or =0.597). Patients with current hypercortisolism scored worse (lower) than those without (44+/-22 vs 56+/-21, P=0.004). Linear regression analysis identified female gender and hypercortisolism as significant predictors for worse QoL.

CONCLUSION

CushingQoL is useful to evaluate HRQoL in patients with CS and correlates with clinical parameters.

Consensus guidelines on screening for hypopituitarism following traumatic brain injury

PRIMARY OBJECTIVE

The goal of this consensus statement is to increase awareness among endocrinologists and physicians treating patients with traumatic brain injury (TBI) of the incidence and risks of hypopituitarism among patients with TBI.

RATIONALE

TBI poses significant risk to the pituitary gland, leading to elevated risks of diabetes, hypopituitarism and other endocrinopathies. Signs and symptoms associated with hypopituitarism often mimic the sequellae of TBI, although the severity of symptoms is not necessarily related to the severity of the injury. Patients with TBI-induced hypopituitarism may benefit both physically and psychologically from appropriate hormone replacement therapy (HRT). Participants at this unique consensus meeting attempted to define and spearhead an approach to increase awareness of the risks of TBI-induced endocrinopathies, in particular growth hormone deficiency (GHD), and to outline necessary and practical objectives for managing this condition.

RECOMMENDATIONS

Systematic screening of pituitary function is recommended for all patients with moderate-to-severe TBI at risk of developing pituitary deficits. Patients with hypopituitarism benefit from appropriate hormonal replacement and prospects for rehabilitation of patients with TBI-induced hypopituitarism may be enhanced by appropriate HRT. Further exploration of this possibility requires: (1) active collaboration between divisions of endocrinology and rehabilitation at the local level to perform a screening of pituitary function in patients after TBI, (2) creation of a consultancy service by endocrine societies for use by rehabilitation centres, (3) development of continuing medical education (CME) programmes that can be offered as crossover training to the physicians who manage the care of patients with TBIs, (4) targeting of patient organizations with educational information for dissemination to patients and their families, (5) continued efforts to more clearly define the population at greatest risk of TBI-induced hypopituitarism and (6) monitor results of efficacy studies as they become available to evaluate whether and how much replacement therapy can improve the symptoms of individuals with TBI-induced hypopituitarism.

Kardiovaskuläre Hochrisikokonstellationen in der primärärztlichen Versorgung

DETECT is a nationwide epidemiological cross-sectional and longitudinal study program in a random probability sample of 3,795 primary care settings (response rate: 60.2%). Based on a target day total assessment of n=55,518 consecutive patients (RR 93.5%) in these settings all patients underwent standardized diagnostic assessment, using self-reporting, clinical interview and laboratory measures. DETECT aims at describing the point prevalence and comorbidity of coronary heart disease (CHD), hyperlipidaemia, arterial hypertension and diabetes mellitus and at identifying the behavioural, clinical, laboratory and psychological risk factors associated with these conditions. A random subset of patients (n=7,519) also completed an extensive standardized laboratory screening program and a 12-month follow-up investigation. Findings reveal a high prevalence of hypertension (36.3%), dyslipidaemia (29.1%), diabetes mellitus (14.6%) and CHD (12.4%) in primary care as well as their close association among each other. The study describes for the first time in greater detail the prevalence of specific disorders and the frequency of high-risk constellations in primary care and allows for the evaluation of various risk scores.

Cardiovascular risk factors in primary care: methods and baseline prevalence rates--the DETECT program

OBJECTIVES

DETECT is an epidemiological study in primary care to examine (a) the prevalence rates and comorbidity of diabetes mellitus, hypertension, hyperlipidaemia and coronary heart disease (CHD), and associated conditions; (b) the frequency of behavioural and clinical risk factors for onset and progression; (c) the 12-month course and outcome; and (d) the met and unmet needs for these patients.

METHODS

Three-stage, cross-sectional clinical-epidemiological study with a prospective-longitudinal component in a nationally representative sample of N = 3795 primary care settings [response rate (RR): 60.2%] and N = 55518 patients (RR: 95.5%). Patients completed a standardized assessment, including questionnaires for patients and the physician and diagnostic screening measures (i.e. blood pressure, heart rate, body mass index and waist circumference assessments). A subsample of patients (N = 7519) also completed a standardized laboratory screening program and was followed-up after 12 months. Data were weighted to adjust for non-response, regional distribution and attrition.

RESULTS

(1) Doctors and patients sample can be regarded as representative for primary care settings in Germany. (2) The clinician-rated point prevalence of hypertension is highest (35.5%), followed by hyperlipidaemia (29.1%), diabetes (14.1%) and CHD (12.1%); prevalence rates of each disorder as well as their co-incidence rates increase markedly with age. (3) The vast majority (78%) of all patients revealed multiple (3+) behavioural and clinical risk factors.

CONCLUSION

The findings of DETECT underline the considerable burden for primary care doctors in managing a highly morbid patient population, with predominantly complex risk factor constellations, in routine care. Our data provide, in unprecedented detail, a basis for calculating age-, gender- and risk-group-adjusted risk-factor profiles in routine care.

Functional cross-talk among cytokines, T-cell receptor, and glucocorticoid receptor transcriptional activity and action

The main communicators between the neuroendocrine and immune systems are cytokines and hormones. We studied the molecular interaction between immune activators (cytokines and T-cell receptors [TCRs]) and the glucocorticoid receptor (GR) in cells in which glucocorticoids play a key regulatory function: (1) cellular targets of TNF-induced cytotoxicity; (2) the pituitary gland; and (3) thymic cells. Cytokines (TNF-alpha and IL-1) increase glucocorticoid-induced transcriptional activity of the GR via the DNA-glucocorticoid response elements (GREs) in cells transfected with a glucocorticoid-inducible reporter plasmid. As a functional physiological correlate, priming of fibroblastic cells with a low dose of TNF significantly increases the sensitivity to glucocorticoid inhibition of TNF-induced apoptosis (without involving NF-kappa B). Priming of AtT-20 mouse corticotrophs and Cushing pituitary cells with IL-1 increases the sensitivity to glucocorticoid inhibition of CRH-induced ACTH/POMC expression. In thymocytes, activation of the T-cell receptor counteracts the glucocorticoid-induced thymic apoptosis by downregulating the glucocorticoid action on GRE-driven apoptotic genes. Thus, cytokines and immune mediators prevent their own deleterious effects not only by stimulating glucocorticoid production, but also by modifying the sensitivity of the target cells for the glucocorticoid counter-regulatory action. The functional cross-talk at the molecular level between immune signals and glucocorticoids is essential to determine the biological response to both mediators and constitutes the ultimate level of interaction between the immune and neuroendocrine mediators.

Improvement of the calcitonin radioimmunoassay

A rapid and specific assay for human serum calcitonin is described. The total assay-time is under 24 h and uses double-antibody in combination with polyethylene glycol to separate bound and free hormone. The antibody has been checked for its affinity to human serum calcitonin by using a Scatchard plot. Geometric dilution of sera from patients with medullary thyroid carcinoma showed a linear relationship with measured values approximating those expected. The use of Florisil to extract human serum calcitonin from sera to make "human calcitonin-free"-serum for standards has been investigated. A series of 52 normal volunteers and 99 patients with medullary thyroid carcinoma or other possible calcitonin-metabolism disorders have been examined. Only the medullary thyroid carcinoma-patients showed significantly elevated results. In the other groups two patients with phaeochromocytoma and one patient from 29 with bronchial carcinoma had elevated serum calcitonin levels.

A rapid and specific method for separation of bound and free antigen in radioimmunoassay systems

This communication reports a method for increasing the speed of separation of bound and free antigen in radioimmunoassay systems with no loss in the specificity of binding. The technique uses a mixture of second antibody and polyethylene glycol. It is not species or antibody specific, and systems using specific first antibodies from rabbit, goat or sheep are all functional. Results for the assay of parathyrin, calcitonin and corticotropin are described here, although the system has been shown to work for triiodothyronine, thyroxin, thyrotropin, thyroxine binding globulin and transferrin. The time taken for the reaction between first and second antibody is in the order of seconds, and the stability of the complex is unchanged over a period of hours.