Identification of a functional Nuclear Localization Signal in the Dual-Leucine-Zipper-Bearing Kinase

Es existieren viele Hinweise darauf, dass proinflammatorische Zytokine wie z.B. TNF-α und IL-1β an dem Verlust der funktionellen Beta-Zellmasse im prädiabetischen Zustand beteiligt sind. Sie führen dabei zur Aktivierung des MAP-Kinase-Wegs unter Einbeziehung von JNK, was zu einer gesteigerten Apoptoserate von Beta-Zellen führt. Die als JNK-Aktivator be-schriebene DLK ist sowohl in die Induktion von Apoptose in Neuronen und Beta-Zellen als auch in die Hemmung von CREB involviert. In der vorliegenden Arbeit sollte zum einen die Frage nach der subzellulären Lokalisation der DLK geklärt werden. Zum anderen sollte die Auswirkung der DLK auf das Beta-Zellüberleben abhängig von ihrer subzellulären Verteilung untersucht werden. Es konnte unter Zuhilfenahme einer insulinproduzierenden Beta-Zelllinie gezeigt werden, dass die unter basalen Bedingungen größtenteils im Zytoplasma und membranär lokalisierte DLK durch den Einfluss der Zytokine TNF-α und IL-1β verstärkt im Kern lokalisiert war. Die erhobenen Daten wurden durch den Einsatz von Immunfluores-zenzmikroskopie, Elektronenmikroskopie sowie der Zellfraktionierung ermittelt. Des Weiteren wurde gezeigt, dass eine JNK-Aktivierung zur Kernakkumulation der DLK beitrug. Dieser Befund ließ sich durch eine JNK-induzierte Dissoziation der DLK von ihrem Adapterprotein JIP erklären. Es konnte eine funktionelle zweiteilige Kernerkennungssequenz innerhalb der DLK identifiziert werden, die notwendig für einen suffizienten Kerntransport der DLK war. In der vorliegenden Arbeit wurden zur besseren Charakterisierung zwei Mutanten hergestellt, die Mutationen innerhalb der basischen NLS-Sequenz trugen. Für beide DLK-NLS-Mutanten konnte eine katalytische Aktivität, im Sinne einer Phosphorylierung von JNK, nachgewiesen werden. Durch Mutation der Kernerkennungssequenz verminderte sich sowohl die Zytokin-induzierte Translokation der DLK in den Kern als auch ihre hemmende Wirkung auf die Beta-Zell-protektive CRE-/CREB- und CBP-abhängige Gentranskription. Diese Befunde sind vor dem Hintergrund, dass CREB eine entscheidende Rolle für die Funktion und Aufrechterhal-tung der Beta-Zellmasse spielt, von besonderem Interesse. Darüber hinaus konnte gezeigt werden, dass sich der Apoptose-induzierende Effekt der DLK in Beta-Zellen durch Mutation der Kernerkennungssequenz vermindert. Es ist daher davon auszugehen, dass die negativen Effekte der DLK auf die Beta-Zelle sowie ihre Apoptose-induzierende Wirkung zumindest in Teilen durch beeinflussende Mechanismen der DLK im Kern hervorgerufen werden. Eine Hemmung der DLK-Translokation in den Kern könnte daher einen effektiven Mechanismus darstellen, um die Beta-Zelle vor dem schädlichen Einfluss der DLK zu schützen und somit das Fortschreiten des Diabetes mellitus Typ II zu verhindern

The Rapid Atrial Swirl Sign for Ultrasound-Guided Tip Positioning of Retrograde-Tunneled Hemodialysis Catheters: A Cross-Sectional Study from a Single Center

Background: Chronic kidney disease (CKD) is a common medical problem in patients worldwide, with an increasing prevalence of patients with end-stage kidney disease (ESKD) requiring renal replacement therapy (RRT). In patients requiring RRT for more than two weeks or those who develop ESKD, tunneled hemodialysis catheter (HDC) insertion is preferred, based on a lower risk for infectious complications. While the efficacy of ultrasound (US)-guided tip positioning in antegrade-tunneled HDCs has previously been shown, its application for the insertion of retrograde-tunneled HDCs has not been described yet. This is especially important, since the retrograde-tunneled technique has several advantages over the antegrade-tunneled HDC insertion technique. Therefore, we here report our first experience of applying the rapid atrial swirl sign (RASS) for US-guided tip positioning of retrograde-tunneled HDCs. Methods: We performed a cross-sectional study to assess the feasibility of applying the RASS for US-guided tip positioning of retrograde-tunneled HDCs. We performed a total number of 24 retrograde-tunneled HDC insertions in 23 patients (requiring placement of a HDC for the temporary or permanent treatment of ESKD) admitted to our Department of Nephrology and Rheumatology at the University Medical Center Göttingen, Germany. Results: The overall success rate of applying the RASS for US-guided tip positioning of retrograde-tunneled HDCs was 24/24 (100%), with proper tip position in the right atrium in 18/23 (78.3%), or cavoatrial junction in 5/23 (21.7%) when RASS was positive and improper position when RASS was negative in 1/1 (100%), confirmed by portable anterior-posterior chest radiography, with only minor post-procedural bleeding in 2/24 (8.3%). In addition, this insertion technique allows optimal HDC flow, without any observed malfunction. Conclusion: This is the first study to investigate the efficacy of the RASS for US-guided tip positioning of retrograde-tunneled HDCs in patients with ESKD. Application of the RASS for US-guided tip positioning is an accurate and safe procedure for the proper placement of retrograde-tunneled HDCs

Effect of baroreflex activation therapy on dipping pattern in patients with resistant hypertension

Abstract A relevant number of patients with resistant hypertension do not achieve blood pressure (BP) dipping during nighttime. This inadequate nocturnal BP reduction is associated with elevated cardiovascular risks. The aim of this study was to evaluate whether a nighttime intensification of BAT might improve nocturnal BP dipping. In this prospective observational study, non‐dippers treated with BAT for at least 6 months were included. BAT programming was modified in a two‐step intensification of nighttime stimulation at baseline and week 6. Twenty‐four hours ambulatory BP (ABP) was measured at inclusion and after 3 months. A number of 24 patients with non‐ or inverted dipping pattern, treated with BAT for a median of 44 months (IQR 25–52) were included. At baseline of the study, patients were 66 ± 9 years old, had a BMI of 33 ± 6 kg/m2, showed an office BP of 135 ± 22/72 ± 10 mmHg, and took a median number of antihypertensives of 6 (IQR 4–9). Nighttime stimulation of BAT was adapted by an intensification of pulse width from 237 ± 161 to 267 ± 170 μs (p = .003) while frequency (p = .10) and amplitude (p = .95) remained unchanged. Uptitration of BAT programming resulted in an increase of systolic dipping from 2 ± 6 to 6 ± 8% (p = .03) accompanied with a significant improvement of dipping pattern (p = .02). Twenty four hours ABP, day‐ and nighttime ABP remained unchanged. Programming of an intensified nighttime BAT interval improved dipping profile in patients treated with BAT, while the overall 24 h ABP did not change. Whether the improved dipping response contributes to a reduction of cardiovascular risk beyond the BP‐lowering effects of BAT, however, remains to be shown

Impact of Elevated LDH on Cystatin C-Based Glomerular Filtration Rate Estimates in Patients with Cancer

Background: The determination of renal function is crucial for the clinical management of patients with cancer. The glomerular filtration rate (GFR) serves as a key parameter, estimated by creatinine clearance determination in 24-h collected urine (CrCl) as well as equation-based approaches (eGFR) relying on serum creatinine (eGFR CKD EPIcrea) or serum cystatin C (eGFR cystatin C). Serum creatinine and serum cystatin C levels differentially depend on muscle and tumor mass, respectively. Although muscle and tumor mass may thus represent confounding factors, comparative studies for eGFR estimate approaches in cancer patients are lacking. Methods: The present study retrospectively analyzed GFR estimates based on equations of creatinine (eGFRcr), cystatin C (eGFRcys) and combined creatinine-cystatin C levels (eGFRcr-cys) in a subset of patients. The associations of LDH with cystatin C or LDH with eGFRcr, eGFRcys and GFRcr-cys were explored. Results: The laboratory values of 123 consecutive patients were included. The median age was 59 (24–87) and 47.2% were female. There was a statistically significant difference in the mean of CKD EPIcrea (85.17 ± 21.63 mL/min/1.73 m2), CKD EPIcys (61.16 ± 26.03 mL/min/1.73 m2) and CKD EPIcrea-cys (70.42 ± 23.89 mL/min/1.73 m2) (p 1.5 UNV and cystatin C values (r = 0.270, p 1.5 UNV were associated with significantly lower CKD EPIcys (r = 0.184, p p Conclusions: The inclusion of cystatin C as a biomarker led to a lower eGFR estimates compared to creatinine alone or in a combination of both cystatin C and creatinine. The level of cystatin C correlated with the level of LDH, suggesting that the use of cystatin C-based calculations of GFR in cancer patients with elevated LDH should be used with caution

Cytokine adsorption therapy in lymphoma-associated hemophagocytic lymphohistiocytosis and allogeneic stem cell transplantation

Lymphoma-associated Hemophagocytic lymphohistiocytosis (HLH) represents a severe complication of disease progression, mediated through cytokine release from the lymphoma cells. Cytokine adsorption may contribute as a supportive treatment to stabilize organ function by reduction of cytokine levels. So far, no experiences of cytokine adsorption and simultaneous stem cell transplantation were published. We report the case of a patient with aggressive lymphoma secondary to chronic lymphocytic leukemia with rapidly progressive HLH (Richter's transformation) upon conditioning chemotherapy prior to allogeneic stem cell transplantation (ASCT). Continuous hemodiafiltration was initiated in the treatment of shock with acute renal failure, lactacidosis and need for high-dose catecholamine therapy, integrating an additional cytokine-adsorbing filter (CytoSorb®) to reduce cytokine levels. This was followed by scheduled allogenic stem cell transplantation. We observed a marked decrease in interleukin-6 plasma levels, associated with a reduced need for vasopressor therapy and organ function stabilization. Hematopoietic engraftment was present at day 14 post-ASCT, leading to disease-free discharge at day 100 post-transplantation. Cytokine adsorption may serve as a safe adjunct to HLH/sepsis treatment during allogeneic stem cell transplantation. Clinical studies are required to make future treatment recommendations

Impact of medication adherence on the efficacy of Baroreflex activation therapy

Abstract Therapy adherence significantly determines the success of antihypertensive therapy, especially in patients with resistant hypertension. Our study investigates the impact of drug adherence on the efficacy of Baroreflex‐activation‐therapy (BAT). In this retrospective analysis, the authors measured blood pressure (BP) and antihypertensive medication adherence (by gas chromatography‐mass spectrometry [GC‐MS] urine analysis) before and 6 months after BAT initiation. Adherence was defined as detection of ≥80% intake of prescribed medication at the time of follow‐up. Response to BAT was defined as BP drop ≥5 mmHg in systolic 24 h‐ambulatory BP (ABP) after 6 months. Overall patients (n = 38) median medication adherence was low, but rose from 60% (IQR 25%–100%) to 75% (IQR 38%–100%; p = .0194). After 6 months of BAT, mean systolic and diastolic office BP (‐21 ± 25 mmHg and ‐9 ± 15 mmHg; p < .0001 and .0004) as well as 24 h‐ABP dropped significantly (‐9 ± 17 mmHg and ‐5 ± 12 mmHg; p = .0049 and .0280). After 6 months of BAT, 21 patients (60%) could be classified as responders. There was neither significant difference in mean office systolic (‐21 ± 23 mmHg vs. ‐21 ± 28 mmHg; p = .9581) nor in 24 h‐systolic ABP decrease (‐11 ± 19 mmHg vs. ‐7 ± 15 mmHg; p = .4450) comparing adherent and non‐adherent patients. Whereas Antihypertensive Therapeutic Index (ATI) was unchanged in non‐responders, it significantly decreased in responders (from 50 ± 16 to 46 ± 16; p = .0477). These data are the first to show that BAT‐initiation leads to a clear BP reduction independently of patients´ medication adherence. Response to BAT is associated with a significant lowering of ATI, which might contribute to an underestimation of BAT efficacy

Urinary Dickkopf-3 (DKK3) Is Associated with Greater eGFR Loss in Patients with Resistant Hypertension

Patients with resistant hypertension (HTN) demonstrate an increased risk of chronic kidney disease and progression to end-stage renal disease; however, the individual course of progression is hard to predict. Assessing the stress-induced, urinary glycoprotein Dickkopf-3 (uDKK3) may indicate ongoing renal damage and consecutive estimated glomerular filtration rate (eGFR) decline. The present study aimed to determine the association between uDKK3 levels and further eGFR changes in patients with resistant HTN. In total, 31 patients with resistant HTN were included. Blood pressure and renal function were measured at baseline and up to 24 months after (at months 12 and 24). uDKK3 levels were determined exclusively from the first available spot urine sample at baseline or up to a period of 6 months after, using a commercial ELISA kit. Distinctions between different patient groups were analyzed using the unpaired t-test or Mann&ndash;Whitney test. Correlation analysis was performed using Spearman&rsquo;s correlation. The median uDKK3 level was 303 (interquartile range (IQR) 150&ndash;865) pg/mg creatinine. Patients were divided into those with high and low eGFR loss (&ge;3 vs. &lt;3 mL/min/1.73 m&sup2;/year). Patients with high eGFR loss showed a significantly higher median baseline uDKK3 level (646 (IQR 249&ndash;2555) (n = 13) vs. 180 (IQR 123&ndash;365) pg/mg creatinine (n = 18), p = 0.0412 (Mann&ndash;Whitney U)). Alternatively, patients could be classified into those with high and low uDKK3 levels (&ge;400 vs. &lt;400 pg/mg creatinine). Patients with high uDKK3 levels showed significantly higher eGFR loss (&minus;6.4 &plusmn; 4.7 (n = 11) vs. 0.0 &plusmn; 7.6 mL/min/1.73 m2/year (n = 20), p = 0.0172 (2-sided, independent t-test)). Within the entire cohort, there was a significant correlation between the uDKK3 levels and change in eGFR at the latest follow-up (Spearman&rsquo;s r = &minus;0.3714, p = 0.0397). In patients with resistant HTN, high levels of uDKK3 are associated with higher eGFR loss up to 24 months later

Cystatin C predicts renal function impairment after partial or radical tumor nephrectomy

Purpose: To test the value of preoperative and postoperative cystatin C (CysC) as a predictor on kidney function after partial (PN) or radical nephrectomy (RN) in renal cell carcinoma (RCC) patients with normal preoperative renal function. Methods: From 01/2011 to 12/2014, 195 consecutive RCC patients with a preoperative estimated glomerular filtration rate (eGFR) > 60 ml/min/1.73m2 underwent surgical RCC treatment with either PN or RN. Logistic and linear regression models tested for the effect of CysC as a predictor of new-onset chronic kidney disease in follow-up (eGFR < 60 ml/min/1.73m2). Moreover, postoperative CysC and creatinine values were compared for kidney function estimation. Results: Of 195 patients, 129 (66.2%) underwent PN. In postoperative and in follow-up setting (median 14 months, IQR 10–20), rates of eGFR < 60 ml/min/1.73m2 were 55.9 and 30.2%. In multivariable logistic regression models, preoperative CysC [odds ratio (OR): 18.3] and RN (OR: 13.5) were independent predictors for a reduced eGFR < 60 ml/min/1.73m2 in follow-up (both p < 0.01), while creatinine was not. In multivariable linear regression models, a difference of the preoperative CysC level of 0.1 mg/dl estimated an eGFR decline in follow-up of about 5.8 ml/min/1.73m2. Finally, we observed a plateau of postoperative creatinine values in the range of 1.2–1.3 mg/dl, when graphically depicted vs. postoperative CysC values (‘creatinine blind area’). Conclusion: Preoperative CysC predicts renal function impairment following RCC surgery. Furthermore, CysC might be superior to creatinine for renal function monitoring in the early postoperative setting

Eligibility for Baroreflex Activation Therapy and medication adherence in patients with apparently resistant hypertension

Abstract Uncontrolled hypertension is a main risk factor for cardiovascular morbidity. Baroreflex activation therapy (BAT) is an effective therapy option addressing true resistant hypertension. We evaluated patients’ eligibility for BAT in a staged assessment as well as adherence to antihypertensive drug therapy. Therefore, we analyzed files of 345 patients, attending the hypertension clinic at University Medicine Göttingen. Additionally, gas chromatographic‐mass spectrometric urine analyses of selected individuals were performed evaluating their adherence. Most common cause for a revoked BAT recommendation was blood pressure (BP) control by drug adjustment (54.2%). Second leading cause was presence of secondary hypertension (31.6%). Patients to whom BAT was recommended (59 (17.1%)) were significantly more often male (67.8% vs. 43.3%, P = .0063), had a higher body mass index (31.8 ± 5.8 vs. 30.0 ± 5.7 kg/m², P = .0436), a higher systolic office (168.7 ± 24.7 vs. 147.7 ± 24.1 mmHg, P < .0001), and 24h ambulatory BP (155.0 ± 14.6 vs. 144.4 ± 16.8 mmHg, P = .0031), took more antihypertensive drugs (5.8 ± 1.3 vs. 4.4 ± 1.4, P < .0001), and suffered more often from numerous concomitant diseases. Eventually, 27 (7.8%) received a BAT system. In the toxicological analysis of 75 patients, mean adherence was 75.1%. 16 patients (21.3%) showed non‐adherence. Thus, only a small number of patients eventually received a BAT system, as treatable reasons for apparently resistant hypertension could be identified frequently. This study is—to our knowledge—the first report of a staged assessment of patients’ suitability for BAT and underlines the need for a careful examination and indication. Non‐adherence was proven to be a relevant issue concerning apparently resistant hypertension and therefore non‐eligibility for interventional antihypertensive therapy

Syndecan-4 as a Marker of Endothelial Dysfunction in Patients with Resistant Hypertension

(1) Background: Arterial hypertension (HTN) is one of the most relevant cardiovascular risk factors. Nowadays multiple pharmaceutical treatment options exist with novel interventional methods (e.g., baroreflex activation therapy (BAT)) as a last resort to treat patients with resistant HTN. Although pathophysiology behind resistant HTN is still not fully understood. There is evidence that selected biomarkers may be involved in the pathophysiology of HTN. (2) Methods: We investigated serum SDC4-levels in patients suffering from resistant HTN before and 6 months after BAT implantation. We collected 19 blood samples from patients with resistant HTN and blood pressure above target and measured serum SDC4-levels. (3) Results: Our results showed high serum SDC4-levels in patients with resistant HTN as compared to a healthy population. Patients with both, resistant HTN and diabetes mellitus type II, demonstrated higher serum SDC4-levels. β-blockers had lowering effects on serum SDC4-levels, whereas calcium channel blockers were associated with higher levels of serum SDC4. BAT implantation did not lead to a significant difference in serum SDC4-levels after 6 months of therapy. (4) Conclusion: Based on our results we propose SDC4 is elevated in patients suffering from resistant HTN. Thus, SDC4 might be a potential marker for endothelial dysfunction in patients with resistant hypertension