Fertility preservation and management of pregnancy in melanoma patients requiring systemic therapy

Melanoma is one of the most common cancers in adolescents and adults at fertile age, especially in women. With novel and more effective systemic therapies that began to profoundly change the dismal outcome of melanoma by prolonging overall survival, the wish for fertility preservation or even parenthood has to be considered for a growing portion of melanoma patients-from the patients' as well as from the physicians' perspective. The dual blockade of the mitogen-activated protein kinase pathway by B-Raf proto-oncogene serine/threonine kinase and mitogen-activated protein kinase inhibitors and the immune checkpoint inhibition by anti-programmed cell death protein 1 and anti-cytotoxic T-lymphocyte-associated protein-4 monoclonal antibodies constitute the current standard systemic approaches to combat locally advanced or metastatic melanoma. Here, the preclinical data and clinical evidence of these systemic therapies are reviewed in terms of their potential gonadotoxicity, teratogenicity, embryotoxicity and fetotoxicity. Recommendations for routine fertility and contraception counseling of melanoma patients at fertile age are provided in line with interdisciplinary recommendations for the diagnostic work-up of these patients and for fertility-protective measures. Differentiated recommendations for the systemic therapy in both the adjuvant and the advanced, metastatic treatment situation are given. In addition, the challenges of pregnancy during systemic melanoma therapy are discussed.

[Insulin therapy-new insulin analogues]

A multitude of short-acting and long-acting insulin analogues are currently available for the treatment of diabetes mellitus, which mimic physiological insulin secretion better than normal insulins. By the use of ultrarapid insulin analogues postprandial glucose increases can be significantly reduced. Newer long-acting insulin analogues have a very stable action profile and reduce the rate of hypoglycemia, especially nocturnal hypoglycemia, even more than first generation long-acting insulin analogues. Future developments focus on a further acceleration of prandial insulin effects with a simultaneous shorter effect time and an even more prolonged action of long-acting insulin analogues.

Steroid Profiling as an Additional Tool to Confirm One-Sided Hormone Overproduction in Primary Aldosteronism: A Case Report

Primary aldosteronism (PA) is the leading cause of secondary hypertension. The source of aldosterone hypersecretion is often due to a unilateral aldosterone-producing adenoma, and unilateral laparoscopic adrenalectomy is recommended in such patients. Before surgery, confirmation of unilateral hypersecretion is necessary. This is optimally performed by adrenal venous sampling (AVS). However, AVS is not always successful e.g., due to difficulties in the cannulation of the right adrenal vein. Here we present the case of a 53-year-old female patient with primary aldosteronism, a left-sided adrenal mass and an inconspicuous right adrenal. AVS was performed, but cannulation of the right adrenal vein failed. Therefore, aldosterone hypersecretion also of the right adrenal could not be excluded despite higher aldosterone concentrations in the left renal and adrenal vein. To increase the certainty that the left sided adrenal mass was the source of aldosterone hypersecretion, steroid profiling was performed in a sample from the inferior vena cava. This revealed markedly elevated levels of 18-oxocortisol, 18-hydroxycortisol, 11-deoxycorticosterone, and 11-deoxycortisol, a steroid profile that strongly suggested that the left sided adrenal mass was an aldosterone producing adenoma, most likely due to a somatic KCNJ5 mutation. Following unilateral adrenalectomy, CYP11B2 immunohistochemistry, and genetics analysis of the resected adrenal confirmed a solitary aldosterone-producing adenoma with intense aldosterone synthase expression, which harbored a previously described KCNJ5 Phe154Cys mutation. Biochemical and clinical cure was confirmed 6 months postoperatively.

[Patients with a wearable cardioverter-defibrillator (WCD) : Prescription, function and rehabilitation support]

Assessment of a permanent risk of life-threatening ventricular arrhythmia in patients with severely reduced left ventricular ejection fraction (LVEF <35%), e. g. after myocarditis, dilated cardiomyopathy, acute myocardial infarction, in patients with postpartum cardiomyopathy or implantable cardioverter-defibrillator (ICD) and cardiac resynchronization treatment plus defibrillator (CRT-D) infection with temporary explantation of the system is a medical challenge. This is time-consuming and unsafe because life-threatening ventricular arrhythmias may occur during the time of risk assessment. During this phase of risk stratification, a wearable cardioverter-defibrillator (WCD) is indicated. The WCD, which is usually worn by the patient for several months, combines continuous retrievable electrocardiogram (ECG) recordings with a reliable defibrillation capability. The prescription of a WCD guarantees safe rehabilitation procedures for patients following acute inpatient treatment. Rehabilitation measures in patients with a WCD are indicated because of the underlying systolic cardiac insufficiency due to severe myocardial disease. In almost half of the patients, who are potentially threatened by ventricular tachyarrhythmias or sudden cardiac death (SCD), the LVEF and heart failure symptoms improve under controlled medication within a few months. Thus, the risk of SCD is lowered so that in many cases a first line ICD implantation is no longer necessary. The purpose of this article is to provide recommendations for rehabilitation procedures of patients with a WCD. A review of the currently available data on WCD publications was carried out with special emphasis on the current national and international guidelines.

Thyroid Allostasis-Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming

The hypothalamus-pituitary-thyroid feedback control is a dynamic, adaptive system. In situations of illness and deprivation of energy representing type 1 allostasis, the stress response operates to alter both its set point and peripheral transfer parameters. In contrast, type 2 allostatic load, typically effective in psychosocial stress, pregnancy, metabolic syndrome, and adaptation to cold, produces a nearly opposite phenotype of predictive plasticity. The non-thyroidal illness syndrome (NTIS) or thyroid allostasis in critical illness, tumors, uremia, and starvation (TACITUS), commonly observed in hospitalized patients, displays a historically well-studied pattern of allostatic thyroid response. This is characterized by decreased total and free thyroid hormone concentrations and varying levels of thyroid-stimulating hormone (TSH) ranging from decreased (in severe cases) to normal or even elevated (mainly in the recovery phase) TSH concentrations. An acute versus chronic stage (wasting syndrome) of TACITUS can be discerned. The two types differ in molecular mechanisms and prognosis. The acute adaptation of thyroid hormone metabolism to critical illness may prove beneficial to the organism, whereas the far more complex molecular alterations associated with chronic illness frequently lead to allostatic overload. The latter is associated with poor outcome, independently of the underlying disease. Adaptive responses of thyroid homeostasis extend to alterations in thyroid hormone concentrations during fetal life, periods of weight gain or loss, thermoregulation, physical exercise, and psychiatric diseases. The various forms of thyroid allostasis pose serious problems in differential diagnosis of thyroid disease. This review article provides an overview of physiological mechanisms as well as major diagnostic and therapeutic implications of thyroid allostasis under a variety of developmental and straining conditions.

Calculated Parameters of Thyroid Homeostasis: Emerging Tools for Differential Diagnosis and Clinical Research

Although technical problems of thyroid testing have largely been resolved by modern assay technology, biological variation remains a challenge. This applies to subclinical thyroid disease, non-thyroidal illness syndrome, and those 10% of hypothyroid patients, who report impaired quality of life, despite normal thyrotropin (TSH) concentrations under levothyroxine (L-T4) replacement. Among multiple explanations for this condition, inadequate treatment dosage and monotherapy with L-T4 in subjects with impaired deiodination have received major attention. Translation to clinical practice is difficult, however, since univariate reference ranges for TSH and thyroid hormones fail to deliver robust decision algorithms for therapeutic interventions in patients with more subtle thyroid dysfunctions. Advances in mathematical and simulative modeling of pituitary-thyroid feedback control have improved our understanding of physiological mechanisms governing the homeostatic behavior. From multiple cybernetic models developed since 1956, four examples have also been translated to applications in medical decision-making and clinical trials. Structure parameters representing fundamental properties of the processing structure include the calculated secretory capacity of the thyroid gland (SPINA-GT), sum activity of peripheral deiodinases (SPINA-GD) and Jostel's TSH index for assessment of thyrotropic pituitary function, supplemented by a recently published algorithm for reconstructing the personal set point of thyroid homeostasis. In addition, a family of integrated models (University of California-Los Angeles platform) provides advanced methods for bioequivalence studies. This perspective article delivers an overview of current clinical research on the basis of mathematical thyroid models. In addition to a summary of large clinical trials, it provides previously unpublished results of validation studies based on simulation and clinical samples.

Nonthyroidal Illness Syndrome in Cardiac Illness Involves Elevated Concentrations of 3,5-Diiodothyronine and Correlates with Atrial Remodeling

BACKGROUND

Although hyperthyroidism predisposes to atrial fibrillation, previous trials have suggested decreased triiodothyronine (T3) concentrations to be associated with postoperative atrial fibrillation (POAF). Therapy with thyroid hormones (TH), however, did not reduce the risk of POAF. This study reevaluates the relation between thyroid hormone status, atrial electromechanical function and POAF.

METHODS

Thirty-nine patients with sinus rhythm and no history of atrial fibrillation or thyroid disease undergoing cardiac surgery were prospectively enrolled. Serum concentrations of thyrotropin, free (F) and total (T) thyroxine (T4) and T3, reverse (r)T3, 3-iodothyronamine (3-T1AM) and 3,5-diiodothyronine (3,5-T2) were measured preoperatively, complemented by evaluation of echocardiographic and electrophysiological parameters of cardiac function. Holter-ECG and telemetry were used to screen for POAF for 10 days following cardiac surgery.

RESULTS

Seven of 17 patients who developed POAF demonstrated nonthyroidal illness syndrome (NTIS; defined as low T3 and/or low T4 syndrome), compared to 2 of 22 (p < 0.05) patients who maintained sinus rhythm. In patients with POAF, serum FT3 concentrations were significantly decreased, but still within their reference ranges. 3,5-T2 concentrations directly correlated with rT3 concentrations and inversely correlated with FT3 concentrations. Furthermore, 3,5-T2 concentrations were significantly elevated in patients with NTIS and in subjects who eventually developed POAF. In multivariable logistic regression FT3, 3,5-T2, total atrial conduction time, left atrial volume index and Fas ligand were independent predictors of POAF.

CONCLUSION

This study confirms reduced FT3 concentrations in patients with POAF and is the first to report on elevated 3,5-T2 concentrations in cardiac NTIS. The pathogenesis of NTIS therefore seems to involve more differentiated allostatic mechanisms.

Second degree AV block and severely impaired contractility in cardiac myxedema: a case report

The heart is a major target organ for thyroid hormone action. Severe overt hypothyroidism can result in diastolic hypertension, lowered cardiac output, impaired left ventricular contractility and diastolic relaxation, pericardial effusion and bradycardia. However, the function of the atrial pacemaker is usually normal and the degree by which the heart rate slows down is often modest. Here we report the case of a 20 year old male Caucasian with severe overt hypothyroidism. He presented with syncopation due to second degree atrioventricular block type Mobitz 2 and heart failure with reduced ejection fraction (38 %). Laboratory testing revealed a severe overt hypothyroidism with markedly elevated TSH (>100 mIU/L) and reduced fT3 and fT4 levels. The condition was caused by hypothyroid Graves’ disease (Graves’ disease with Hashimoto component). Although magnetic resonance imaging of the heart demonstrated decreased cardiac contractility and pericardial effusion, suggesting peri-myocarditis, plasma levels for BNP and troponin I were low. A possible infectious cause was unlikely, since testing for cardiotropic viruses was negative. The patient was treated with intravenous levothyroxine and after peripheral euthyroidism had been achieved, left ventricular ejection fraction returned to normal and pericardial effusion dissolved. Additionally, bradycardiac episodes abated, although intermittent second degree AV block was still occasionally present during the night. In conclusion, overt hypothyroidism may be associated by cardiac myxedema affecting both electrophysiology and contractility, observations that underscore the necessity of thyroid testing in different phenotypes of heart failure.

The treatment of type 2 diabetes

BACKGROUND

5% to 8% of adults have type 2 diabetes, a disease that is usually asymptomatic at first. The goals of management are timely diagnosis and the prevention of complications.

METHODS

Selective review of the literature, including guidelines from Germany and abroad.

RESULTS

High caloric intake and lack of exercise are the main contributing causes of type 2 diabetes and the principal targets of intervention. If lifestyle changes do not yield adequate improvement, then drug treatment should be initiated (or intensified) and managed on the basis of the HbA1c fraction. Guidelines recommend an HbA1c target range of 6.5% to 7.5%; the individual target value should be chosen in consideration of patient-specific factors and established in collaboration with the patient. Metformin is recommended for initial drug treatment. If metformin is contraindicated, poorly tolerated, or inadequately effective, many therapeutic alternatives and supplements are available. Clinical trials have shown that sulfonylureas and insulin are beneficial with respect to patient-relevant endpoints, but comparable data from clinical trials are not yet available for any other antidiabetic drug (except metformin). For individual patients, other drugs may have advantages such as a lower risk of hypoglycemia, less weight gain, oral administration, and/or applicability in the setting of renal insufficiency. The treatment is individually oriented, depending on the patient's age, disease stage, body weight, comorbidities, work situation, adherence, and personal priorities. Combining more than two antidiabetic drugs is not recommended.

CONCLUSION

Although there are many treatment options, individualized long-term treatment still presents a challenge in many cases.

[Fitness to drive in patients with implanted cardioverter-defibrillator]

A physician who takes care for patients with implanted cardioverter-defibrillator (ICD) must inform them about their fitness to drive since these patients carry a higher risk for the occurrence of syncope or sudden cardiac death at the wheel. The driver's license law in Germany does not mention patients with ICD. The fitness to drive of patients with ICD is covered by the Advisory Board for Traffic Medicine in Germany (Bundesanstalt für Straßenwesen). These guidelines, however, are outdated and cannot be used to inform patients. Actually, these guidelines are under revision. Currently, the position paper of the German Society of Cardiology on "Fitness to drive and cardiovascular diseases" together with a recently published Dutch paper on this topic forms the basis of these recommendations. One week after ICD implantation for primary or one month after implantation for secondary prevention the patient may resume to drive. After adequate shocks the fitness to drive can be expected 2-4 months (3 months) later. The assessment of the fitness to drive has to be performed individually, taking into account also possible other influencing factors. In individual cases it appears to be justified that patients with ICD work as professional drivers.

The proteomic signature of insulin-resistant human skeletal muscle reveals increased glycolytic and decreased mitochondrial enzymes

AIMS/HYPOTHESIS

The molecular mechanisms underlying insulin resistance in skeletal muscle are incompletely understood. Here, we aimed to obtain a global picture of changes in protein abundance in skeletal muscle in obesity and type 2 diabetes, and those associated with whole-body measures of insulin action.

METHODS

Skeletal muscle biopsies were obtained from ten healthy lean (LE), 11 obese non-diabetic (OB), and ten obese type 2 diabetic participants before and after hyperinsulinaemic-euglycaemic clamps. Quantitative proteome analysis was performed by two-dimensional differential-gel electrophoresis and tandem-mass-spectrometry-based protein identification.

RESULTS

Forty-four protein spots displayed significant (p < 0.05) changes in abundance by at least a factor of 1.5 between groups. Several proteins were identified in multiple spots, suggesting post-translational modifications. Multiple spots containing glycolytic and fast-muscle proteins showed increased abundance, whereas spots with mitochondrial and slow-muscle proteins were downregulated in the OB and obese type 2 diabetic groups compared with the LE group. No differences in basal levels of myosin heavy chains were observed. The abundance of multiple spots representing glycolytic and fast-muscle proteins correlated negatively with insulin action on glucose disposal, glucose oxidation and lipid oxidation, while several spots with proteins involved in oxidative metabolism and mitochondrial function correlated positively with these whole-body measures of insulin action.

CONCLUSIONS/INTERPRETATION

Our data suggest that increased glycolytic and decreased mitochondrial protein abundance together with a shift in muscle properties towards a fast-twitch pattern in the absence of marked changes in fibre-type distribution contribute to insulin resistance in obesity with and without type 2 diabetes. The roles of several differentially expressed or post-translationally modified proteins remain to be elucidated.

Long-term graft function of cryostored alginate encapsulated rat islets

Microencapsulation of pancreatic islets before transplantation is a promising approach to enable graft function in an immunocompetent recipient without immunosuppression. However, the insufficient availability of allogenic islet tissue is a major problem. One concept to overcome these shortcomings is the cryopreservation of encapsulated allogenic islets. Recently, we reported a gentle cryopreservation protocol for rat islets encapsulated in an alginate-based microcapsule system. Here, we report for the first time long-term transplantation data of these cryopreserved microencapsulated islets. We detected a stable graft function for more than 12 month (experiments still continuing) after transplantation of 2500 cryopreserved microencapsulated CD rat islets in streptozotocin-diabetic Wistar rats. Moreover, the glucose clearance rate during an IPGTT was well preserved up to 56 weeks after transplantation. In addition, hyperglycemic blood glucose levels after removal of rat islet grafts 12 and 56 weeks after transplantation confirmed the efficacy of the encapsulated islets. Finally, the retrieved encapsulated rat islets responded well with a 7-fold increase of insulin secretion to a glucose stimulus (12 and 56 weeks). In conclusion, our study demonstrates for the first time that cryopreservation of encapsulated rat islets is possible without substantial losses on graft function for a very long time.

Protection from diabetes development by single-chain antibody-mediated delivery of a NF-κB inhibitor specifically to β-cells in vivo

Recently, we reported the generation of single-chain antibodies (SCAs) highly specific for rodent and human β-cells. Our current report describes the generation of a fusion protein of one of these SCAs (SCA B1) with a NF-κB essential modifier (NEMO)-binding domain (NBD) peptide, thereby creating a selective inhibitor of NF-κB activation in β-cells. The SCA B1-NBD fusion protein was cloned in the pIRES-EGFP, expressed in bacteria, and purified by metal affinity chromatography; the newly generated complex was then administered intravenously to rodents and evaluated for its ability to protect β-cells against cytokines in vitro and diabetogenic agents in vivo. First, it was shown clearly that our SCA B1-NBD fusion protein binds highly selective to CD rat β-cells in vivo. Second, we observed that SCA B1-mediated in vivo delivery of the NBD peptide completely blocked IL-1β + IFNγ- and TNFα + IFNγ-mediated induction of NF-κB as well as islet dysfunction in culture. Finally, repeated intravenous injection of SCA B1-NBD prior to multiple low-dose administration of streptozotocin in CD mice not only induced a striking resistance to diabetes development but also preserved β-cell mass. In conclusion, our data show for the first time that a SCA B1-NBD fusion peptide reliably protects β-cells against cytokines in vitro and allows protection from diabetes development in CD mice in vivo.

In vitro phage display in a rat beta cell line: a simple approach for the generation of a single-chain antibody targeting a novel beta cell-specific epitope

AIMS/HYPOTHESIS

The aim of the present study was to evaluate in vitro phage display in a beta cell line as a novel strategy for the isolation of beta cell-specific agents/biomarkers.

METHODS

A single-chain antibody (SCA) library was pre-incubated with AR42J cells in order to eliminate SCAs with exocrine binding properties. It was then panned against INS-1 cells to select beta cell-targeted antibodies.

RESULTS

By these means, we isolated a novel antibody, SCA B5, that binds rapidly (6.0 min) and with a 450-fold higher specificity to beta cells relative to exocrine cells. We estimated for SCA B5 a binding affinity in the low micromol/l range and 858 binding sites per beta cell. Confocal microscopy showed binding to the beta cell surface and confirmed subsequent internalisation. Moreover, staining of rat and human pancreatic tissue sections with SCA B5 suggests that the target epitope is presented in pancreatic beta cells of different origins. Infrared imaging revealed that labelling of beta cells with tracer SCA B5 is strictly dependent on beta cell mass. With competition assays we excluded insulin, glutamate decarboxylase, C-peptide and islet amyloid polypeptide as SCA B5 targets. In accordance with these predictions, SCA B5 homed in vivo highly selectively to normal beta cells and dysfunctional beta cells of diabetic rats. Moreover, accumulation of radioactively labelled SCA B5 in the pancreas was reduced by 80% after pre-injection with unlabelled SCA B5, thereby confirming the specific uptake in the pancreas.

CONCLUSIONS/INTERPRETATION

We report a simple strategy for the generation of an SCA targeting a novel beta cell-specific epitope.

Beta-cell development and turnover during prenatal life in humans

INTRODUCTION

beta-cell regeneration is an area under active investigation for the future treatment of diabetes, but little is known about the patterns and dynamics of prenatal beta-cell development in humans. In particular, the quantitative changes in beta-cell mass in the developing pancreas have not been elucidated in detail. We addressed the following questions in prenatal humans: i) what is the timing of beta-cell occurrence and islet growth? ii) What are the dynamics of beta-cell replication and apoptosis?

METHODS

Pancreatic tissue was obtained from 65 human embryos and foetuses aged between 8 weeks post conception (p.c.) and birth. Sections were stained for insulin, glucagon, Ki67 (proliferation marker), TUNEL (apoptosis marker) and CD31 (blood vessel marker), and morphometric analyses were performed.

RESULTS

beta-cells were detected from gestational week 9 onward, whereas glucagon expression was detected already at week 8. The fractional beta-cell area of the pancreas increased in a linear fashion until birth (r=0.60, P<0.001). The first endocrine cells were found within or adjacent to the primitive ductal epithelium. beta-cell replication was readily detected in the newly forming islets already starting at week 9 p.c. (average frequency 2.8+/-0.4%). A small percentage of cells co-expressed insulin and glucagon during the early foetal period. There was a close relationship between the development of endocrine islets and blood vessels during all stages of prenatal pancreas development suggesting a possible interaction between both cell types. The frequency of beta-cell apoptosis was relatively high throughout all ages (1.5+/-0.3%).

CONCLUSIONS

beta-cell differentiation in humans occurs from week 9 p.c. onward. The first endocrine cells are closely associated with the ductal epithelium suggesting differentiation from precursor cells. High rates of beta-cell replication suggest that this mechanism plays an important role in the prenatal expansion of beta-cell mass.

Generation of novel single-chain antibodies by phage-display technology to direct imaging agents highly selective to pancreatic beta- or alpha-cells in vivo

OBJECTIVE

Noninvasive determination of pancreatic beta-cell mass in vivo has been hampered by the lack of suitable beta-cell-specific imaging agents. This report outlines an approach for the development of novel ligands homing selectively to islet cells in vivo.

RESEARCH DESIGN AND METHODS

To generate agents specifically binding to pancreatic islets, a phage library was screened for single-chain antibodies (SCAs) on rat islets using two different approaches. 1) The library was injected into rats in vivo, and islets were isolated after a circulation time of 5 min. 2) Pancreatic islets were directly isolated, and the library was panned in the islets in vitro. Subsequently, the identified SCAs were extensively characterized in vitro and in vivo.

RESULTS

We report the generation of SCAs that bind highly selective to either beta- or alpha-cells. These SCAs are internalized by target cells, disappear rapidly from the vasculature, and exert no toxicity in vivo. Specific binding to beta- or alpha-cells was detected in cell lines in vitro, in rats in vivo, and in human tissue in situ. Electron microscopy demonstrated binding of SCAs to the endoplasmatic reticulum and the secretory granules. Finally, in a biodistribution study the labeling intensity derived from [(125)I]-labeled SCAs after intravenous administration in rats strongly predicted the beta-cell mass and was inversely related to the glucose excursions during an intraperitoneal glucose tolerance test.

CONCLUSIONS

Our data provide strong evidence that the presented SCAs are highly specific for pancreatic beta-cells and enable imaging and quantification in vivo.

Regulation of glucose-6-phosphatase gene expression by insulin and metformin

The biguanide derivative metformin is a potent anti-diabetic drug widely used in the treatment of type 2 diabetes mellitus. Its major effect on glucose metabolism consists in the inhibition of hepatic glucose production. Since the mechanisms of metformin action are only partially understood at the molecular level, we studied the regulation of the gene promoter activity of glucose-6-phosphatase (G6Pase), the central hepatic gluconeogenic enzyme, by this drug. We have found that both metformin and insulin inhibit the basal and dexamethasone/cAMP-stimulated G6Pase promoter activity in hepatoma cells. Since one of the pharmacological targets of metformin is AMP-activated protein kinase (AMPK) and activation of AMPK is known to inhibit hepatic glucose production by the suppression of G6Pase gene transcription, we studied the effect of AMPK in this context. Under nonstimulated conditions, the inhibitory effect of both insulin and metformin was partially counteracted to a similar extent by treatment with compound C, a specific inhibitor of AMPK. In contrast, under conditions of stimulation with dexamethasone and cAMP, treatment with compound C reversed the inhibitory effect of metformin on G6Pase promoter activity to a similar extent as compared to nonstimulated conditions, whereas the effect of insulin was almost resistant to treatment with the AMPK-antagonist. These data indicate a differential AMPK-dependent regulation of G6Pase gene expression by insulin and metformin under basal and dexamethasone/cAMP-stimulated conditions.

Effects of a short-term improvement in glycaemic control on skin microvascular dysfunction in Type 1 and Type 2 diabetic patients

AIMS

To investigate whether Type 1 and Type 2 diabetic patients differ in the effects of short-term improvement in glycaemic control on skin microvascular dysfunction.

METHODS

Fourteen Type 1 and 14 Type 2 diabetic patients admitted to hospital to improve glycaemic control were investigated. Two age- and sex-matched groups of non-diabetic subjects served as controls. Capillary blood cell velocity (CBV) was assessed at the dorsal middle phalangeal area of the ring finger at rest and after 3-min arterial occlusion using laser Doppler anemometry.

RESULTS

Comparing the measurements before and after improvement in glycaemic control, there were no significant changes in peak CBV, time to peak CBV and vasomotion amplitudes in Type 1 and Type 2 diabetic patients. On admission to hospital, time to peak CBV was prolonged in Type 1 (20.9 +/- 2.9 vs. 12.3 +/- 1.6 s, P = 0.003) and Type 2 diabetic patients (20.6 +/- 2.6 vs. 11.9 +/- 1.3 s, P = 0.021) compared with control subjects. After improvement in glycaemic control, there was no significant difference in time to peak CBV between Type 1 diabetic patients and their control subjects (17.8 +/- 4.2 vs. 12.3 +/- 1.6 s, P = 0.535). In Type 2 diabetic patients, the time to peak CBV increased non-significantly.

CONCLUSIONS

Short-term improvement in glycaemic control did not appear to reverse microcirculatory dysfunction in Type 1 and Type 2 diabetes. However, there was an improvement of the delayed reactive hyperaemia in Type 1 diabetic patients.

The AQUA-FONTIS study: protocol of a multidisciplinary, cross-sectional and prospective longitudinal study for developing standardized diagnostics and classification of non-thyroidal illness syndrome

BACKGROUND

Non-thyroidal illness syndrome (NTIS) is a characteristic functional constellation of thyrotropic feedback control that frequently occurs in critically ill patients. Although this condition is associated with significantly increased morbidity and mortality, there is still controversy on whether NTIS is caused by artefacts, is a form of beneficial adaptation, or is a disorder requiring treatment. Trials investigating substitution therapy of NTIS revealed contradictory results. The comparison of heterogeneous patient cohorts may be the cause for those inconsistencies.

OBJECTIVES

Primary objective of this study is the identification and differentiation of different functional states of thyrotropic feedback control in order to define relevant evaluation criteria for the prognosis of affected patients. Furthermore, we intend to assess the significance of an innovative physiological index approach (SPINA) in differential diagnosis between NTIS and latent (so-called "sub-clinical") thyrotoxicosis.Secondary objective is observation of variables that quantify distinct components of NTIS in the context of independent predictors of evolution, survival or pathophysiological condition and influencing or disturbing factors like medication.

DESIGN

The approach to a quantitative follow-up of non-thyroidal illness syndrome (AQUA FONTIS study) is designed as both a cross-sectional and prospective longitudinal observation trial in critically ill patients. Patients are observed in at least two evaluation points with consecutive assessments of thyroid status, physiological and clinical data in additional weekly observations up to discharge. A second part of the study investigates the neuropsychological impact of NTIS and medium-term outcomes.The study design incorporates a two-module structure that covers a reduced protocol in form of an observation trial before patients give informed consent. Additional investigations are performed if and after patients agree in participation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00591032.

[New concepts in the treatment of type 2 diabetes]

The development of a variety of new substances will considerably expand the therapeutic choices in the treatment of type 2 diabetes. In 2006, the endocannabinoid receptor blocker Rimonabant has been approved for the treatment of type 2 diabetes in Germany. This compound has led to significant reductions of body weight along with improvements of HbA1c levels and lipid profiles, but the lack of health insurance coverage limits its large scale use in germany. In April 2007, the first members of the GLP 1 analogues/incretin mimetics (exenatide, Byetta) and DPP 4 inhbitors (sitagliptin, Januvia) have become available for the treatment of type 2 diabetes in Germany. Both drugs have significantly lowered HbA1c levels in clinical studies. In addition, the incretin mimetics have caused a progressive reduction of body weight, while the DPP 4 inhibitors have been rather weight neutral. Sitagliptin can be administered orally, whereas exenatide has to be injected subcutaneously. Neither the DPP 4 inhibitors, nor the incretin mimetics have led to the development of hypoglycaemia, unless combined with sulfonylureas. Overall, the introduction of these new drug classes will certainly broaden our therapeutic choices in the management of type 2 diabetes. The long-term effects of these drugs on the development of diabetic complications in long-term trials remains to be awaited.

[The metabolic syndrome]

The "metabolic syndrome" consists of some common risk factors for cardiovascular diseases: central obesity, diabetes mellitus, hyperlipidaemia and hypertension. The metabolic syndrome (MTS) leads to increased morbidity and mortality and to higher direct and indirect healthcare costs. The MTS can be diagnosed using the NCEP/ATP III criteria. The prevalence of the MTS in Germany is estimated at 23.8% and is expected to rise further, due to increasing obesity among children and adolescents. Studies have shown that the MTS leads to increased cardiovascular and total mortality and thus to a decreased life expectancy. Studies estimating the total costs of MTS are missing, but after addition of the costs for all the risk factors it is assumed that MTS costs amount to 5% of total healthcare costs. This is the result of the more frequent demand of health services and longer hospitalisation of patients with MTS. Even moderate weight loss can decrease the rates of morbidity and healthcare costs.

Microvascular dysfunction in rheumatoid arthritis assessed by laser Doppler anemometry: relationship to soluble adhesion molecules and extraarticular manifestations

In search of a noninvasive diagnostic test for rheumatoid vasculitis (RV), this study addressed the questions whether changes in capillary blood cell velocity (CBV) detected by laser Doppler anemometry in patients with rheumatoid arthritis (RA) were correlated with the levels of soluble adhesion molecules and whether cutaneous flow abnormalities may reflect extraarticular manifestations in RA. In 31 RA patients and 20 patients with osteoarthritis (OA), CBV was measured in the skin above the left ring finger at rest and after 3-min arterial occlusion. Serum levels of soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble E-selectin (sE-selectin), and soluble P-selectin (sP-selectin) were assessed by enzyme linked immunosorbent assay. Peak CBV was reduced in RA patients compared to OA patients (0.42 +/- 0.07 mm/s vs. 0.70 +/- 0.13 mm/s; P = 0.013). Both CBV during rest and reactive hyperemia were not correlated with the levels of soluble adhesion molecules. There were no significant differences in resting or peak CBV between RA patients with or without extraarticular manifestations. The lack of an inverse correlation between the levels of soluble adhesion molecules and CBV during rest and reactive hyperemia contradicts the assumption that inflammatory vascular damage indicated by increased levels of soluble adhesion molecules was the main reason for the impairment of microcirculation. The present results do not suggest that cutaneous flow abnormalities may reflect extraarticular manifestations in RA.

Calpain inhibition impairs glycogen syntheses in HepG2 hepatoma cells without altering insulin signaling

Calpains are a family of non-lysosomal cytoplasmatic cysteine proteases. Since calpain 10 (CAPN10), a member of the calpain family of proteases, has been found to represent a putative diabetes susceptibility gene, it was argued that calpains may be involved in the development of type 2 diabetes. The functional role of calpains in insulin signaling and/or insulin action is, however, not clear. We investigated the effects of the calpains 1 and 2 inhibitor PD151746 on insulin signaling and insulin action in human hepatoma G2 cells (HepG2). HepG2 cells were incubated without (-PD) or with (+PD) 5.33 micromol/l PD151746 for different times and then stimulated with 100 nmol/l insulin for 0 (t(0)), 5 (t(5)), 15 (t(15)), 30 (t(30)), 45 (t(45)), and 60 (t(60)) min. After solubilization of the cells, insulin receptor kinase activity, tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1), IRS-1-associated phosphatidylinositol-3 kinase (PI3-kinase), PI3-kinase activity, Thr(308) phosphorlyation of Akt, amount of protein tyrosine phosphatase-epsilon (PTPepsilon), and glycogen synthase activity were determined. Incubation with PD151746 resulted in a significant reduction of insulin-stimulated glycogen synthesis compared with cells not pre-incubated with the calpain inhibitor (-PD: t(0), 4.90 +/- 1.20%; t(5), 5.90 +/- 1.02%; t(15), 5.29 +/- 0.95%; t(30), 5.60 +/- 1.10%; t(45), 5.52 +/- 0.90%; t(60), 5.67 +/- 0.97%;+PD: t(0), 4.56 +/- 1.10%; t(5), 6.16 +/- 1.05%; t(15), 7.52 +/- 1.09%; t(30), 7.68 +/- 1.10%; t(45), 8.28 +/- 0.89%; t(60), 7.69 +/- 0.98%; P < 0.05). Incubation with PD151746 significantly increased the protein amount of PTPepsilon in the cells after 12 h (-PD: t(1), 0.85 +/- 0.18 RU (Relative unit); t(8), 0.87 +/- 0.18 RU; t(12), 0.9 +/- 0.13 RU; +PD: t(1), 0.92 +/- 0.21 RU; t(8), 1.1 +/- 0.15 RU; t(12), 1.34 +/- 0.16 RU; P < 0.05). Calpain inhibition with PD151746 had no effect on the insulin stimulation of the investigated insulin signaling parameters. These results in HepG2 cells suggest that calpains play a role in the hepatic regulation of insulin-stimulated glycogen synthesis independent of the PI3-kinase/Akt signaling pathway.