PCSK-9-inhibitor therapy improves endothelial function in high-risk patients with cardiovascular disease

Background

Impaired endothelial function predicts cardiovascular events. The aim of this study was to analyse the effect of evolocumab on endothelial function in patients with cardiovascular disease and on obligatory statin therapy.

Methods

This was a prospective, double-blinded, randomized, controlled, single center study including patients with cardiovascular disease (diagnosis of coronary artery disease, non-hemorrhagic stroke, transient ischemic attack or symptomatic peripheral artery disease) and treated with statins, similar to the inclusion criteria of the FOURIER study. Patients were consecutively randomized (1:1) to either evolocumab treatment (420mg was administrated in monthly intervals, twice during the study) or placebo. All patients underwent examination of endothelial function at baseline, and after 1, 4 and 8 weeks of treatment by a semi-automatic high-resolution ultrasound system (UNEX EF 18G; Unex Co., Nagoya, Japan). Endothelial function parameter such as flow-mediated vasodilation (FMD; vasodilator responsiveness), low flow-mediated vasocontriction (L-FMC; vasoconstrictor responsiveness) and vasoactive range (VAR; total vasomotor responsiveness) were measured.

Results

103 patients with a mean age of 66.2 (±7.7) years and a mean LDL-cholesterol of 98.2 (±19.1) mg/dl completed the study. 83.5% of the study population was known to have coronary artery disease. Endothelial function parameter (VAR) increased after 8 weeks of treatment with evolocumab compared to baseline (p=0.034), whereas there was no significant change at 1 and 4 weeks after treatment. Moreover, an improvement in VAR from baseline at week 8 was found with evolocumab compared to placebo (p=0.045).

In a subgroup analysis, in patients with age ≤67 years, lower systolic blood pressure (≤125 mmHg) or higher baseline LDL-cholesterol (>95 mg/dl), significant evolocumab treatment effect was found in VAR improvement (p=0.006, p=0.049 and p=0.042, respectively) from baseline at week 8. No serious adverse event related to study medication occurred during the study.

Conclusion

Our data indicate that endothelial function could be improved with evolocumab treatment in high-risk patients with preexisting cardiovascular disease and on statin therapy. Our results contribute to the mechanistic explanation why lower incidence of the cardiovascular composite endpoint has been demonstrated in the FOURIER study.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): AMGEN GmbH

Effect of empagliflozin on ketone bodies in patients with stable chronic heart failure

Background

Recent studies indicated that sodium glucose cotransporter (SGLT)2 inhibition increases levels of ketone bodies in the blood in patients with type 1 and 2 diabetes. Other studies suggested that in patients with chronic heart failure (CHF), increased myocardial oxygen demand can be provided by ketone bodies as a fuel substrate. Experimental studies reported that ketone bodies, specifically beta-hydroxybutyrate (β-OHB) may increase blood pressure (BP) by impairing endothelium-dependant relaxation, thereby leading to increased vascular stiffness. In our study we assessed whether the SGLT 2 inhibition with empagliflozin increases ketone bodies in patients with stable CHF and whether such an increase impairs BP and vascular function.

Methods

In a prospective, double blind, placebo controlled, parallel-group single centre study 75 patients with CHF (left ventricular ejection fraction 39.0 ± 8.2%) were randomised (2:1) to the SGLT-2 inhibitor empagliflozin 10 mg orally once daily or to placebo, 72 patients completed the study. After a run-in phase we evaluated at baseline BP by 24 h ambulatory blood pressure (ABP) monitoring, vascular stiffness parameters by the SphygmoCor system (AtCor Medical, Sydney, NSW, Australia) and fasting metabolic parameters, including β-OHB by an enzymatic assay (Beckman Coulter DxC 700 AU). The same measurements were repeated 12 weeks after treatment. In 19 of the 72 patients serum levels of β-OHB were beneath the lower border of our assay (< 0.05 mmol/l) therefore being excluded from the subsequent analysis.

Results

In patients with stable CHF, treatment with empagliflozin (n = 36) was followed by an increase of β-OHB by 33.39% (p = 0.017), reduction in 24 h systolic (p = 0.038) and diastolic (p = 0.085) ABP, weight loss (p = 0.003) and decrease of central systolic BP (p = 0.008) and central pulse pressure (p = 0.008). The increase in β-OHB was related to an attenuated decrease of empagliflozin-induced 24 h systolic (r = 0.321, p = 0.069) and diastolic (r = 0.516, p = 0.002) ABP and less reduction of central systolic BP (r = 0.470, p = 0.009) and central pulse pressure (r = 0.391, p = 0.033). No significant changes were seen in any of these parameters after 12 weeks of treatment in the placebo group (n = 17).

Conclusion

In patients with stable CHF ketone bodies as assessed by β-OHB increased after treatment with empagliflozin. This increase led to an attenuation of the beneficial effects of empagliflozin on BP and vascular parameters.

Trial registration The study was registered at http://www.clinicaltrials.gov (NCT03128528).

Predictors of blood pressure response after renal denervation beyond pretreatment blood pressure

Background

The principle of initial value (Wilder's law of initial value) proposes that the “direction of response of body function to any agent depends to a large degree on the initial value of that function”. Indeed, in several trials on renal denervation (RDN), pre-treatment blood pressure (BP) has been consistently and repeatedly found to predict the decrease in BP after RDN. Efforts to discover further statistically significant and clinically meaningful predictors of BP response to RDN failed.

Objective

By use of a new methodological approach, we aimed to determine predictors of BP response after RDN in patients with resistant hypertension.

Methods

The study population comprised 266 patients with resistant hypertension (mean age 62 years, 34% females, mean BMI 30.5 kg/m2, 27% had coronary heart disease, 42% had diabetes mellitus and 61% had hypercholesterolaemia) who underwent radiofrequency RDN with the Symplicity catheter at the Universities of Homburg and Erlangen. Clinical data including 24h ambulatory BP (ABP) were obtained prior to, and 3, 6 and 12 months after RDN. The primary parameter of response was defined as change in 24-hour systolic ABP after 6 months from pre-treatment values. As expected, change in 24h systolic ABP correlated with pre-treatment 24h systolic ABP (r2 linear = 0.225, p&lt;0.001), with change in 24h systolic ABP = 73.82 + 0.55 x pre-treatment 24h systolic ABP. To overcome the predominant role of the pre-treatment BP that may mask other factors, we calculated for each individual patient the “expected systolic ABP decrease” by applying this regression equation and the “excessive systolic ABP decrease” by subtracting the measured from expected change in 24h systolic ABP. We divided the study population into 2 groups (above [responders] and below [non-responders] of the median change in excessive 24h systolic ABP.

Results

Neither pre-treatment 24h systolic or diastolic ABP, nor office systolic or diastolic BP differed between the two groups (all p&gt;0.20). Following RDN, 24h systolic ABP decreased in the responders by −23.3±16 vs non-responders +1.4±11 mmHg at 6 month, and 24h systolic ABP values were also significantly lower in responders at 3 and 12 months (all p&lt;0.001), without difference in number of antihypertensive drugs between the groups. Of all clinical variables at baseline, office heart rate (65.6 vs 68.7±12 bpm, p=0.024) and HbA1c (6.07±0.88 vs. 6.37±1.23%, p=0.035) were lower in responders compared with non-responders. Finally, a multiple regression analysis confirmed that pre-treatment 24h systolic ABP (beta +0.565, p&lt;0001), HbA1c (beta −0.167, p=0.004) and office HR (beta +0.106, p=0.057) were independent predictors of decrease in 24h systolic ABP.

Conclusion

In patients with resistant hypertension, lower HbA1c and office HR were identified as predictors of BP response in addition to pre-treatment BP. This finding may help to identify hypertensive patients who benefit most from RDN.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Extramural grant provided vy Medtronic INc

Reduced tissue sodium content is related to improvement of vascular function in patients with chronic heart failure treated with the SGLT2 inhibitor empagliflozin

Background

Large randomized controlled trials have demonstrated that SGLT2 inhibitors produce cardiovascular benefits beyond their metabolic effects. One of the assumed underlying mechanisms is the reduction of the left ventricular afterload. Factors aggravating the afterload are impaired vascular function (ventricular-arterial coupling) as well as high tissue sodium content, which exerts enhanced hypertrophic stimuli and exaggerated response to vasoconstrictors.

Purpose

We hypothesized that the SGLT2 inhibitor empagliflozin leads to afterload reduction in patients with chronic heart failure (CHF) by reducing tissue sodium content and improving vascular function and that these changes are related to each other.

Methods

In a randomized (2:1), investigator initiated, double-blind, placebo controlled, parallel-group, prospective clinical study, patients with CHF NYHA II-III and an ejection fraction of 49% or less were randomized to empagliflozin 10mg once daily or placebo. In each patient, we assessed vascular parameters under resting conditions (Sphygmocor) and 24-hour daily life conditions (Mobilograph), including central systolic pressure (cSBP) and central pulse pressure (cPP) among others. In parallel, we measured tissue (skin and muscle) sodium content of the lower leg by Sodium-MRI, at baseline and after 1 month of therapy.

Results

A total of 74 patients (men: n=62), aged 66±9 years, with a mean ejection fraction of 39±9% were included. Only 24% of the patients had type 2 diabetes. After 1 month treatment with empagliflozin, a decrease of skin sodium content was observed (22.8±6.1 vs. 21.6±6.0 mmol/l, p=0.039), while there was no significant change in muscle sodium and muscle water content. A decrease of cSBP (117.1±14.5 vs. 110.7±11.3 mmHg, p&lt;0.001) and cPP (41.4±8.8 vs. 38.4±8.5 mmHg, p=0.004) under resting conditions was observed after 1 month treatment with empagliflozin, while changes in the placebo group were not significant for cSBP (117.0±18.1 vs. 116.3±15.0 mmHg, p=0.759) and cPP (40.6±9.1 vs. 39.4±8.6 mmHg, p=0.422). Similarly, there was a decrease of cSBP and cPP in patients with empagliflozin treatment under ambulatory conditions, but not in the placebo group. In the whole group, we observed a significant correlation between change in skin sodium content and change in vascular parameters such as cSBP (r=0.364, p=0.004) and cPP (r=0.250, p=0.054) after 1 month of treatment with empagliflozin or placebo.

Conclusion(s)

Significant changes in skin sodium content induced by empagliflozin and a significant correlation between changes in skin sodium content and vascular function suggest that a reduction of tissue sodium content may be one of the mechanisms underlying the beneficial effects of SGLT2 inhibitors in heart failure.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Boehringer Ingelheim International GmbH.

Relation between functional and cognitive impairments in remitted patients with bipolar disorder and suggestions for trials targeting cognition: An exploratory study

BACKGROUND

Trials targeting cognition in bipolar disorder (BD) are advised to include a measure of functional capacity as key secondary or co-primary outcome to assess whether treatment efficacy on cognition translates into enhanced functional capacity. However, it is unclear which measure of functional capacity shows the strongest association with objectively-measured cognition and may thus be best suited for inclusion in cognition trials.

METHODS

Participants (N = 58) with BD in partial or full remission with objective cognitive impairment and healthy controls (N = 37) were assessed with mood ratings and were given a comprehensive battery of neuropsychological tests and a questionnaire assessing subjective cognitive function, respectively. They were also assessed with performance-based, interview-based and self-reported measures of functional capacity. Associations between objective and subjective cognition and measures of functional capacity were assessed with correlation analyses. For significant correlations, multiple regression analyses were conducted to assess if the associations remained significant after adjustment for clinical and demographic variables.

RESULTS

Objectively-measured cognition was directly associated with performance-based functional capacity (β = 0.37, p < 0.01) also after adjustment for clinical and demographic variables, but not with self-reported or interview-based functional capacity (ps ≥0 .20). In contrast, subjective cognitive complaints were associated with self-reported (β = 0.59, p < 0.01) and interview-based functional capacity (β = 0.47, p < 0.01), but not performance-based functional capacity (ps ≥ 0.28).

LIMITATIONS

The cross-sectional design and modest sample size.

CONCLUSIONS

A performance-based measure of functional capacity seems most feasible for inclusion as a secondary outcome in cognition trials to capture improved functional capacity following treatment-related improvements in cognition.

1416Combined therapy of empagliflozin and linagliptin is superior to metformin and insulin glargine in improving blood pressure and vascular function in type 2 diabetes

Background and purpose

The optimal choice of antidiabetic medication in patients that need combined therapy is under debate. The aim of this study was to analyze whether beyond glucose control the combination of empagliflozin (E) and linagliptin (L) improves blood pressure (BP) and vascular function in patients with type 2 diabetes (T2DM) as opposed to the combination of metformin (M) and insulin glargine (I).

Methods

This was a prospective, randomized, controlled, single center study including 101 patients with T2DM, who were randomized 1:1 to E 10–25mg combined with L 5mg once daily or M 850 or 1000mg twice daily combined with I once daily. All patients underwent BP measurement and vascular function analysis by validated systems at baseline and after 12 weeks of treatment.

Results

In comparison to baseline, office, 24-hour ambulatory BP as well as central blood and pulse pressure (PP) values decreased significantly after 12 weeks of treatment with E+L, whereas there was no change in the M+I group (see table). Twenty-four-hour peripheral systolic (mean difference: −5.2±1.5mmHg, p=0.004) and diastolic BP (−1.9±1.0mmHg, p=0.036), central clinical systolic BP (−5.56±1.9mmHg, p=0.009), forward pressure pulse height (−2.0±0.9mmHg, p=0.028), 24-h central systolic BP (−3.6±1.4mmHg, p=0.045) and 24-h pulse wave velocity (−0.14±0.05m/s, p=0.043) were reduced to a greater extent in the E+L than in the M+I group.

Empagliflozin+Linagliptin Metformin+Insulin Baseline 12 weeks p value Baseline 12 weeks p value Peripheral ambulatory BP values   24-h SBP [mmHg] 131.0±10.9 127.0±8.8 <0.001 131.0±9.7 131.0±8.6 0.438   24-h DBP [mmHg] 81.5±7.1 79.7±7.0 0.013 81.0±7.1 81.0±7.5 0.976 Clinical (laboratory) central vascular parameters   Central SBP [mmHg] 123.0±9.6 117.0±10.4 <0.001 121.0±9.9 121.0±8.3 0.944   Central PP [mmHg] 44.4±8.0 41.4±6.6 0.004 43.5±8.6 42.8±7.5 0.471   Forward pressure pulse height [mmHg] 33.0±5.7 30.2±4.6 <0.001 32.5±5.6 31.8±4.5 0.216   Central office PWV [m/s] 8.2±1.6 8.0±1.5 0.039 8.4±1.3 8.3±1.2 0.400 24-h ambulatory central vascular parameters   Central 24-h SBP [mmHg] 120.5±9.3 117.3±7.9 0.007 121.0±9.1 121.0±8.0 0.608   Central 24-h DBP [mmHg] 83.2±7.3 81.1±6.9 0.016 82.4±7.1 82.4±7.7 0.928   Central 24-h PWV [m/s] 8.9±1.3 8.8±1.3 0.010 9.0±1.4 9.0±1.3 0.349 SBP, systolic blood pressure; DBP, diastolic blood pressure; PP, pulse pressure; PWV, pulse wave velocity.

Conclusion

The combination of E+L significantly improves BP and vascular function in contrast to the combination of M+I.

Acknowledgement/Funding

This IIS was supported by a research grant from Boehringer Ingelheim International GmBH

P4993Tissue sodium concentration emerged as a determinant of hypertrophic vascular remodeling in type 2 diabetes

Background

Studies describe a linkage between greater sodium intake and higher incidence of organ damage and cardiovascular end points. Sodium intake is usually assessed by measuring 24-hour urinary sodium excretion, which is prone to high fluctuation. For the assessment of tissue sodium a new technique (23Na-MRI) has been developed. We analyzed whether tissue sodium is linked to vascular remodeling of small resistance vessels in patients with type-2 diabetes.

Methods

In patients with type 2 diabetes we assessed tissue sodium content and vascular structural parameters of the retinal arterioles, since structural changes of resistance vessels (150–300 μm) can be non-invasively and reliably assessed in the retinal circulation by Scanning Laser Doppler Flowmetry (SLDF). Patients with antidiabetic medication were off the therapy (antihypertensives were kept constant) for 4 weeks. The structural parameters of retinal arterioles assessed were outer- and inner diameter (OD & ID), wall thickness (WT), wall-to-lumen ratio (WLR) and wall cross sectional area (WCSA). Tissue sodium content was assessed non-invasively with a 3.0 T clinical MRI system in each patient. Subject placed their lower legs in the center of a 23Na knee coil and sodium content in skin and muscle (musculus triceps surae) were measured.

Results

In patients with type 2 diabetes (N=52) we observed a significant correlation between tissue sodium content (muscle and skin) and OD, WT and WCSA and a trend has been noticed between muscle sodium content and ID and WLR. Multiple linear regression analysis demonstrated that tissue sodium content is a significant determinant of hypertrophic vascular remodeling as indicated by increased WT and WCSA, independent of age, gender and 24-hour ambulatory diastolic blood pressure.

Correlation coefficients Muscle sodium content (mmol/l) Skin sodium content (mmol/l) OD (μmol) r=0.402, p=0.003 r=0.299, p=0.033 ID (μmol) r=0.265, p=0.058 r=0.202, p=0.154 WT (μm) r=0.402, p=0.003 r=0.313, p=0.026 WLR r=0.247, p=0.078 r=0.171, p=0.230 WCSA (μm2) r=0.417, p=0.002 r=0.322, p=0.021

Conclusion

With the novel 23Na-MRI technology, we could demonstrate that high tissue sodium concentration is linked to with hypertrophic vascular remodeling of retinal arterioles. Thus, the reduction of tissue sodium content may emerge as a therapeutic target.

Real-Time Reconstruction of the Strong-Field-Driven Dipole Response

The reconstruction of the full temporal dipole response of a strongly driven time-dependent system from a single absorption spectrum is demonstrated, only requiring that a sufficiently short pulse is employed to initialize the coherent excitation of the system. We apply this finding to the time-domain observation of Rabi cycling between doubly excited atomic states in the few-femtosecond regime. This allows us to pinpoint the breakdown of few-level quantum dynamics at the critical laser intensity near 2  TW/cm^{2} in doubly excited helium. The present approach unlocks single-shot real-time-resolved signal reconstruction across timescales down to attoseconds for nonequilibrium states of matter. In contrast to conventional pump-probe schemes, there is no need for scanning time delays in order to access real-time information. The potential future applications of this technique range from testing fundamental quantum dynamics in strong fields to measuring and controlling ultrafast chemical and biological reaction processes when applied to traditional transient-absorption spectroscopy.

SGLT-2-inhibition with dapagliflozin reduces tissue sodium content: a randomised controlled trial

Background and aims

Sodium tissue content by ²³Na magnetic resonance imaging (Na-MRI) has been validated in experimental and human studies. SGLT-2 inhibition blocks the reabsorption of glucose and of sodium in the proximal tubular cells in a 1:1 fashion. We hypothesized that SGLT-2 inhibition in patients with type 2 diabetes characterized by sodium retention leads to decreased tissue sodium content due to its pharmacological action.

Materials and methods

In a prospective double blind, placebo controlled, cross-over trial 59 patients (61 ± 7.6 years) with type 2 diabetes were randomized to either dapagliflozin 10 mg or placebo once daily for 6 weeks each. In addition to metabolic parameters and ambulatory blood pressure (BP) we analysed the sodium content in the skin and muscles of the lower leg by Na-MRI.

Results

Compared to baseline 6 weeks treatment with the SGLT-2 inhibitor dapagliflozin decreased fasting (132 ± 28 vs. 114 ± 19 mg/dl, p < 0.001), postprandial blood glucose (178 ± 66 mg/dl vs. 153 ± 46 mg/dl, p < 0.001), body weight (87.6 vs. 86.6 kg, p < 0.001) and systolic (129 ± 12 vs. 126 ± 11 mmHg, p = 0.010), and diastolic (77.4 ± 9 vs. 75.6 ± 8 mmHg, p = 0.024), 24-h ambulatory BP. Tissue sodium content in the skin was reduced after 6 weeks treatment with dapagliflozin compared to baseline [24.1 ± 6.6 vs. 22.7 ± 6.4 A.U.(arbitrary unit) p = 0.013]. No significant reduction of tissue sodium content was observed in the muscle (M. triceps surae: 20.5 ± 3.5 vs. 20.4 ± 3.7 A.U. p = 0.801). No clear significant difference in tissue water content of muscle and skin was observed after 6 weeks of treatment with dapagliflozin, compared to baseline.

Conclusion

SGLT-2 inhibition with dapagliflozin resulted in a significant decrease in tissue sodium content of the skin after 6 weeks. This observation point to a decrease of total sodium content in patients with type 2 diabetes prone to cardiovascular complications, that might be mitigated by SGLT-2 inhibition.

Trial registration The study was registered at http://www.clinicaltrials.gov (NCT02383238) retrospectively registered

Observing the ultrafast buildup of a Fano resonance in the time domain

Although the time-dependent buildup of asymmetric Fano line shapes in absorption spectra has been of great theoretical interest in the past decade, experimental verification of the predictions has been elusive. Here, we report the experimental observation of the emergence of a Fano resonance in the prototype system of helium by interrupting the autoionization process of a correlated two-electron excited state with a strong laser field. The tunable temporal gate between excitation and termination of the resonance allows us to follow the formation of a Fano line shape in time. The agreement with ab initio calculations validates our experimental time-gating technique for addressing an even broader range of topics, such as the emergence of electron correlation, the onset of electron-internuclear coupling, and quasi-particle formation.

Revisiting adult neurogenesis and the role of erythropoietin for neuronal and oligodendroglial differentiation in the hippocampus

Recombinant human erythropoietin (EPO) improves cognitive performance in neuropsychiatric diseases ranging from schizophrenia and multiple sclerosis to major depression and bipolar disease. This consistent EPO effect on cognition is independent of its role in hematopoiesis. The cellular mechanisms of action in brain, however, have remained unclear. Here we studied healthy young mice and observed that 3-week EPO administration was associated with an increased number of pyramidal neurons and oligodendrocytes in the hippocampus of ~20%. Under constant cognitive challenge, neuron numbers remained elevated until >6 months of age. Surprisingly, this increase occurred in absence of altered cell proliferation or apoptosis. After feeding a ¹⁵N-leucine diet, we used nanoscopic secondary ion mass spectrometry, and found that in EPO-treated mice, an equivalent number of neurons was defined by elevated ¹⁵N-leucine incorporation. In EPO-treated NG2-Cre-ERT2 mice, we confirmed enhanced differentiation of preexisting oligodendrocyte precursors in the absence of elevated DNA synthesis. A corresponding analysis of the neuronal lineage awaits the identification of suitable neuronal markers. In cultured neurospheres, EPO reduced Sox9 and stimulated miR124, associated with advanced neuronal differentiation. We are discussing a resulting working model in which EPO drives the differentiation of non-dividing precursors in both (NG2+) oligodendroglial and neuronal lineages. As endogenous EPO expression is induced by brain injury, such a mechanism of adult neurogenesis may be relevant for central nervous system regeneration.

Ivy leaves extract based – lipid nanocarriers and their bioefficacy on antioxidant and antitumor activities

Two issues were addressed in the paper: (1) the use of medicinal herbs as functional ingredients entrapped into lipid-based nanocarriers; (2) the efficacy of phytochemical-based nanocarriers with promising antioxidant and antitumor benefits.

Interferometric phase detection at x-ray energies via Fano resonance control

Modern x-ray light sources promise access to structure and dynamics of matter in largely unexplored spectral regions. However, the desired information is encoded in the light intensity and phase, whereas detectors register only the intensity. This phase problem is ubiquitous in crystallography and imaging and impedes the exploration of quantum effects at x-ray energies. Here, we demonstrate phase-sensitive measurements characterizing the quantum state of a nuclear two-level system at hard x-ray energies. The nuclei are initially prepared in a superposition state. Subsequently, the relative phase of this superposition is interferometrically reconstructed from the emitted x rays. Our results form a first step towards x-ray quantum state tomography and provide new avenues for structure determination and precision metrology via x-ray Fano interference.

Posttranslational protein modifications by reactive nitrogen and chlorine species and strategies for their prevention and elimination

Proteins are subject to various posttranslational modifications, some of them being undesired from the point of view of metabolic efficiency. Prevention of such modifications is expected to provide new means of therapy of diseases and decelerate the process of aging. In this review, modifications of proteins by reactive nitrogen species and reactive halogen species, is briefly presented and means of prevention of these modifications and their sequelae are discussed, including the denitrase activity and inhibitors of myeloperoxidase.

Circadian rhythm and day to day variability of serum potassium concentration: a pilot study

BACKGROUND

Hyperkalemia is a common and life-threatening complication frequently seen in patients with acute kidney injury, end-stage renal disease and chronic heart failure. Cardiac arrest and ventricular fibrillation are possible consequences. Biosensors are currently being developed to measure serum potassium under ambulatory conditions and trigger an alarm if the potassium concentration exceeds normal limits. Only few studies exist on the circadian rhythm of potassium; and its dependence on age and kidney function is less clear.

METHODS

Our observational monocentric exploratory study included 30 subjects of which 15 had impaired renal function (RF) (GFR <60 ml/min/1.73 m(2)). Subjects were further categorized into three age groups: 18-39 years (N normal RF = 5, N impaired RF = 4), 40-59 years (N normal RF = 5, N impaired RF = 6), 60-80 years (N normal RF = 5, N impaired RF = 5). Serum potassium levels were measured every 2 h during a 24 h period and repeated once after 2, 4, or 6 days.

RESULTS

In the 15 subjects with normal RF, the lowest mean potassium level (3.96 ± 0.14 mmol/l) was observed at 9 p.m. and the greatest (4.23 ± 0.23 mmol/l) at 1 p.m. In patients with impaired RF the lowest mean potassium level (4.20 ± 0.32 mmol/l) was observed at 9 p.m. and the highest (4.57 ± 0.46 mmol/l) at 3 p.m. The range between the mean of minimum and maximum was greater in patients with impaired RF (0.71 ± 0.45 mmol/l) than in subjects with normal RF (0.53 ± 0.14 mmol/l) [p < 0.001]. No difference in the circadian rhythm was found between the first and second examination.

CONCLUSION

Our results indicate that patients with normal and impaired RF have comparable circadian patterns of serum potassium concentrations, but higher fluctuations in patients with impaired RF. These results have clinical relevance for developing an automatic biosensor to measure the potassium concentration in blood under ambulatory conditions in patients at high risk for potassium fluctuations.

23-Year-Old Female with an Inflammatory Myofibroblastic Tumour of the Breast: A Case Report and a Review of the Literature

Purpose: Inflammatory myofibroblastic tumours (IMT) are a subcategory of inflammatory pseudotumours (IPT). They arise most commonly in the abdominopelvic region, lung and retroperitoneum, but virtually any anatomical site may be involved. Predominantly children and adolescents are affected and there is a tendency for local recurrence. In the literature up to the present, 20 patients have been reported with an IPT/IMT of the breast. We would like to present another patient with this unusual tumour entity of the breast and discuss the literature. Patient and Examinations: A 23-year-old woman presented with a painless lump in her left breast. There was no history of breast cancer in her family. Sonography showed a hypoechoic heterogeneous solid mass with irregular margins. A core needle biopsy revealed a tumour of high cellularity and a densely collagenous background. Immunohistochemically, the spindle-shaped cells were immunoreactive to smooth muscle actin and ALK-1 protein. Additional FISH analysis proved ALK rearrangements on chromosome 2p23 leading to the diagnosis of an IMT. Wide surgical excision was performed with no evidence of local recurrence after 12 months. Conclusion: Three of the above mentioned 20 patients with IMT/IPT of the breast developed a recurrent tumour, none presented with distant metastasis. A significant recurrence rate of 15 % leads to a clinically and sonographically close follow-up in these patients.

Interobserver agreement in mr enterography for diagnostic assessment in patients with Crohn's disease

PURPOSE

To evaluate the extent to which MRE can be used as an observer-independent, objective imaging method for the diagnosis and evaluation of CD with respect to the detection of inflammatory changes of the small bowel and lymphadenopathy as diagnostic criterion and bowel distension as a quality criterion.

MATERIALS AND METHODS

MRE scans of 84 patients (42 female, median age 37 years) were evaluated independently by 4 experienced radiologists. Analysis of inflammatory changes of the bowel wall, lymphadenopathy and adequate bowel distension was conducted separately for the jejunum, ileum and terminal ileum. The Kendall's W-test was used for the statistical comparison of concordance.

RESULTS

In a total of 55 patients, inflammatory activity of the bowel wall was detected and MRE was found to have a high interobserver reproducibility concerning inflammatory changes of the intestinal wall (Kendall's W 0.527 – 0.823). Concerning lymphadenopathy (31 cases, 36.9 %), a low to moderate consensus could be shown with a Kendall's W value of 0.402 – 0.505. For the assessment of adequate bowel distension, a moderate concordance between the operators could be found (Kendall's W 0.497 – 0.581).

CONCLUSION

MRE has proven high interobserver agreement with respect to the diagnosis of inflammatory disease activity of the bowel as a diagnostic criterion in patients with CD. Concerning adequate bowel distension as a quality criterion of the examination itself and lymphadenopathy as a diagnostic criterion, moderate interobserver agreement could be found. This is thought to have a rather small effect on the diagnostic significance and conclusiveness of the method in the daily routine.

Identification and immunocytochemical characterization of Piccolino, a novel Piccolo splice variant selectively expressed at sensory ribbon synapses of the eye and ear

Piccolo is one of the largest cytomatrix proteins present at active zones of chemical synapses, where it is suggested to play a role in recruiting and integrating molecules relevant for both synaptic vesicle exo- and endocytosis. Here we examined the retina of a Piccolo-mutant mouse with a targeted deletion of exon 14 in the Pclo gene. Piccolo deficiency resulted in its profound loss at conventional chemical amacrine cell synapses but retinal ribbon synapses were structurally and functionally unaffected. This led to the identification of a shorter, ribbon-specific Piccolo variant, Piccolino, present in retinal photoreceptor cells, bipolar cells, as well as in inner hair cells of the inner ear. By RT-PCR analysis and the generation of a Piccolino-specific antibody we show that non-splicing of intron 5/6 leads to premature translation termination and generation of the C-terminally truncated protein specifically expressed at active zones of ribbon synapse containing cell types. With in situ proximity ligation assays we provide evidence that this truncation leads to the absence of interaction sites for Bassoon, Munc13, and presumably also ELKS/CAST, RIM2, and the L-type Ca²⁺ channel which exist in the full-length Piccolo at active zones of conventional chemical synapses. The putative lack of interactions with proteins of the active zone suggests a function of Piccolino at ribbon synapses of sensory neurons different from Piccolo’s function at conventional chemical synapses.

[MR enterography sequence evaluation for patients with Crohn's disease]

PURPOSE

To evaluate a routine MR enterography (MRE) protocol for patients with Crohn's disease (CD) in order to assess and rank the subjectively most important sequences regarding diagnostic decisions.

MATERIALS AND METHODS

We prospectively examined 84 patients (42 male) with known CD using a coronal T2 / T1-weighted balanced SSFP (TrueFISP), axial T2-weighted single shot TSE (HASTE) as well as an axial T1-weighted gradient-echo sequence (2D-FLASH) before intravenous contrast application and a 2D-FLASH sequence with axial and coronal orientation after intravenous contrast application. 4 experienced radiologists subjectively evaluated the sequences independently using a scale between 1 and 5 (1 = excellent; 5 = non-diagnostic) regarding their diagnostic significance for a final radiologic decision. The ranking of the different sequences was statistically tested by the Friedman analysis.

RESULTS

The following ranking was found: HASTE sequences were ranked prior to contrast-enhanced axial gradient-echo (2D-FLASH). The third to fifth ranking was TrueFISP, the axial contrast-enhanced 2D-FLASH and the 2D-FLASH without contrast, respectively. Differences between the first and second rank were significant (p < 0.05), and all other differences were highly significant (p < 0.01).

CONCLUSION

The stable and fast T2-weighted MR sequences without intravenous contrast represented by axial HASTE and coronal TrueFISP were ranked as number 1 and 3. The examination protocol should be completed by a coronal T1-weighted gradient-echo-sequence after contrast injection, which can be supplemented by an axial acquisition. The T1-weighted gradient-echo sequence without contrast could be omitted.

MicroRNAs in malignant melanoma

Melanoma is the most aggressive form of skin cancer, and the incidence of melanoma has been increasing faster than that of most other cancers. While the survival rate following surgical resection of early-stage primary tumors is nearly 100%, the survival of patients with metastasized tumors is strongly reduced, likely due to resistance to conventional therapies. Therefore, it is important to use new molecular approaches to develop new biomarkers to better prevent and diagnose melanoma. MicroRNAs (miRNAs) are short non-coding RNAs that post-transcriptionally regulate gene expression via repression of translation or direct degradation of their complementary mRNA. In this review, we summarize our current understanding of the involvement of miRNAs and their corresponding targets in melanomagenesis as well as the potential use of miRNAs as biomarkers.