P6453Activation of necroptotic pathway by downregulated caspase-8 expression is associated with progression of left ventricular remodeling in nonischemic dilated cardiomyopathy

Background

Necroptosis, a form of programmed necrosis, has been suggested to be involved in the pathogenesis of various pathological conditions including heart failure. Protein expression of caspase-8, an endogenous inhibitor of necroptosis, is reported to be downregulated in human failing hearts, but its clinical significance remains unclear.

Methods

Endomyocardial biopsy specimens were obtained from patients with nonischemic dilated cardiomyopathy (n=57, 56.2±14.5 years old, 70% male). The area stained with antibodies against caspase-8 and phospho-MLKL-Ser358 was calculated using an image analyzer, and fibrotic and cardiomyocyte areas were determined by Masson's Trichrome staining. Using a level of median caspase-8 expression (6.04% of the area of the myocardium with caspase-8 signal), patients were classified into a high caspase-8 expression group (H-cas8) and a low caspase-8 expression group (L-cas8).

Results

Caspase-8 signals were detected in cytoplasm and intercalated disks of cardiomyocytes. Patients in the L-cas8 group was younger (51.3±13.1 vs. 61.2±14.3 years old) and had larger left ventricular end-diastolic volume (LVEDV: 174±49 vs. 131±41 ml), larger left ventricular end-systolic volume (LVESV: 123±51 vs. 87±39 ml), and higher ratio of mitral peak velocity of early filling to late diastolic filling (E/A: 1.94±1.48 vs. 1.12±0.66) compared with the H-cas8 group. Caspase-8 expression level was positively correlated with age (r=0.34, p=0.01) and negatively correlated with LVEDV (r=−0.47, p<0.01), LVESV (r=−0.40, p<0.01), and E/A (r=−0.39, p<0.01) in simple linear regression analysis. The extent of myocardial fibrosis was not correlated with caspase-8 expression level. Multiple regression analysis indicated that LVEDV, LVESV, and E/A were independent explanatory factors of caspase-8 expression level after adjusting age and sex. Phospho-MLKL signals, an index of activation of necroptotic pathway, were frequently observed in cytoplasm, intercalated disks, and nuclei in the L-cas8 group but not in the H-cas8 group.

Conclusion

Lower caspase-8 expression in cardiomyocytes was associated with increased phosphorylation of MLKL and larger left ventricular volume, suggesting that downregulated caspase-8 may contribute to progression of myocardial remodeling via activation of MLKL in human dilated cardiomyopathy.

Preserving β-cell function is the major determinant of diabetes remission following laparoscopic sleeve gastrectomy in Japanese obese diabetic patients

Laparoscopic sleeve gastrectomy has been proven effective in treating obesity-associated type 2 diabetes mellitus (T2DM). However, reports of the effect of laparoscopic sleeve gastrectomy on glucose metabolism in Japanese obese patients with T2DM are rare. The aim of this study was to evaluate the effects of laparoscopic sleeve gastrectomy on glucose tolerance in Japanese obese patients with T2DM, and to analyze factors influencing diabetes remission after surgery. This was a retrospective analysis of data for 24 consecutive patients with T2DM who underwent laparoscopic sleeve gastrectomy. We investigated weight loss and its impact on T2DM 1 year postoperatively. We also compared baseline characteristics and postoperative factors between patients who achieved diabetes remission and patients without remission. Mean body weight loss and percent total weight loss were 23.9 kg and 23.3%, respectively. Mean hemoglobin A1c levels dropped from 7.3 ± 0.3% to 6.1 ± 0.2%, and 18 patients (75%) achieved diabetes remission 1 year postoperatively. Patients achieving remission had significantly lower hemoglobin A1c levels (p = 0.026), higher fasting C-peptide values (p < 0.001), shorter diabetes duration (p < 0.001), lower insulin requirement (p = 0.002), and higher area under the insulin response curve (p < 0.001) and insulinogenic index (p < 0.001) during oral glucose tolerance testing. In conclusion, laparoscopic sleeve gastrectomy is an effective treatment for Japanese obese patients with T2DM. Preserving insulin secretion is the major determinant of diabetes remission.

OS8.1 A phase 0/2 clinical trial of a CDK4/6 inhibitor in aggressive meningioma patients

BACKGROUND

New approaches are urgently needed for aggressive meningiomas, which remain largely incurable. Forkhead Box M1 (FOXM1) has been identified as a master transcription factor in aggressive meningiomas and Cyclin D-dependent Kinases (CDK) are positive regulators of cell-cycle entry, promoting tumorigenesis through FOXM1 activation. We evaluated the tumor pharmacokinetics (PK), tumor pharmacodynamics (PD), and preliminary clinical response of ribociclib, a selective CDK4/6-inhibitor, in aggressive meningioma patients.

MATERIAL AND METHODS

Eight aggressive WHO Grade II/III meningioma patients with intact RB expression were enrolled and administered oral ribociclib daily (900mg) for 5 days prior to tumor resection. Plasma, tumor, and cerebrospinal fluid (CSF) samples were collected at 2, 8, or 24 h after the last dose. Total and unbound drug concentrations were determined using a validated LC-MS/MS method. PD effects, including RB and FoxM1 phosphorylation, were compared to matched archival tissue. Patients with PK and PD responses in tumor tissue, defined as unbound ribociclib concentration > 5-fold in vitro IC50 (0.04µM) and >20% decrease in pRB levels, respectively, were enrolled into an exploratory Phase 2 cohort.

RESULTS

The median CSF concentration of ribociclib was 0.25 µM. In tumor tissue, the median unbound ribociclib concentration was 1.36 µM and the median unbound tumor-to-plasma ratio was 5.34. Suppression of G1-to-S phase was inferred in tumors with declining FoxM1 phosphorylation (50%), RB phosphorylation (38%), and cellular proliferation (75%). Four patients demonstrated concurrent PK and PD responses and were graduated to continuous ribociclib therapy. At one year, two of these patients (one Grade II and one Grade III) demonstrate partial responses per RANO criteria.

CONCLUSION

Ribociclib achieves pharmacologically-active concentrations in aggressive meningioma tissue. Target modulation was demonstrated by a decrease in FOXM1-mediated tumor proliferation. Further investigation of ribociclib as a therapeutic strategy for aggressive meningiomas is warranted.

Basic evaluation of a novel 4D target and human body phantom

Stereotactic body radiation therapy (SBRT) is usually verified with a dynamic phantom or solid phantom, but there is a demand for phantoms that can accurately simulate tumor dynamics within an individual that would allow customized validation in every patient. We developed a new 4D dynamic target phantom (multi-cell 4D phantom) that allows simulation of tumor movement in patients. The basic quality and dynamic reproducibility of this new phantom was verified in this investigation. The newly developed multi-cell 4D phantom comprises four main components: soft tissue, bones, lungs, and tumor (target). The phantom structure was based on computed tomography (CT) data of a male. In this study, we investigated the basic performance of a multi-cell 4D phantom. All the CT numbers of the phantom were very close to those of human data. The geometric maximum amplitudes were 4.57 mm in the lateral direction, 4.59 mm in the ventrodorsal direction, and 3.68 mm in the cranio-caudal direction. Geometric errors were 0.84, 0.58, and 0.40 mm, respectively. Movements of the abdominal surface were stable for 60 s. Repeated measurements show no actual differences in target movements between multiple measurements and indicated high reproducibility (r  >  0.97). End-to-end tests using Gafchromic film revealed a gamma pass rate of 98% or above (2 mm/3%). Although our phantom performed limited reproducibility in the movement of the patient tumor at present, a satisfactory level of precision was confirmed in general. This is a very promising device for use in the verification of radiation therapy for moving targets.

Microbiome potentiates endurance exercise through intestinal acetate production

The intestinal microbiome produces short-chain fatty acids (SCFAs) from dietary fiber and has specific effects on other organs. During endurance exercise, fatty acids, glucose, and amino acids are major energy substrates. However, little is known about the role of SCFAs during exercise. To investigate this, mice were administered either multiple antibiotics or a low microbiome-accessible carbohydrate (LMC) diet, before endurance testing on a treadmill. Two-week antibiotic treatment significantly reduced endurance capacity versus the untreated group. In the cecum acetate, propionate, and butyrate became almost undetectable in the antibiotic-treated group, plasma SCFA concentrations were lower, and the microbiome was disrupted. Similarly, 6-wk LMC treatment significantly reduced exercise capacity, and fecal and plasma SCFA concentrations. Continuous acetate but not saline infusion in antibiotic-treated mice restored their exercise capacity (P < 0.05), suggesting that plasma acetate may be an important energy substrate during endurance exercise. In addition, running time was significantly improved in LMC-fed mice by fecal microbiome transplantation from others fed a high microbiome-accessible carbohydrate diet and administered a single portion of fermentable fiber (P < 0.05). In conclusion, the microbiome can contribute to endurance exercise by producing SCFAs. Our findings provide new insight into the effects of the microbiome on systemic metabolism.

Surgical approaches for condylar fractures related to facial nerve injury: deep versus superficial dissection

The aim of this study was to investigate the probability of facial nerve injury (FNI) in the treatment of condylar neck and subcondylar fractures (CN/SCFs) with percutaneous approaches and to identify factors predicting FNI. The data of 80 patients with 87 CN/SCFs were evaluated retrospectively. The primary outcome was FNI occurrence. The predictor variables were age, sex, aetiology, alcohol consumption, fracture site and pattern (dislocation or not), concomitant fractures, time interval to surgery, surgeon experience, plate type, and the dual classification of percutaneous approaches. The approaches were classified based on whether subcutaneous dissection traversed the marginal mandibular branch (MMB) deeply (deep group: submandibular and retroparotid approaches) or superficially (superficial group: transparotid, transmasseteric anteroparotid (TMAP), and high cervical-TMAP approaches). Twenty-two patients (27.5%) suffered FNI, of whom two in the deep group had permanent paralysis of the MMB. In the multivariate logistic regression model, deeply traversing surgery approaches (odds ratio 12.4, P=0.025) and the presence of a dislocated fracture (odds ratio 6.66, P=0.012) were associated with an increased risk of FNI. These results suggest that percutaneous approaches in the superficial group should be recommended for the treatment of CN/SCFs to reduce the risk of FNI.

Correction to: Japanese Clinical Practice Guideline for Diabetes 2016

[This corrects the article DOI: 10.1007/s13340-018-0345-3.].

New Results on Excited States in the one-particle one-hole nucleus 56Co measured with MINIBALL detectors

The non-yrast states of the odd-odd nucleus 56Co have been investigated by studying the γ-rays induced in the predominantly fusion-evaporation reaction 56Fe(p,n γ)56Co at an incident energy of 10 MeV. The γ-rays were measured in-beam with four high-resolution MINIBALL-triple germanium (Ge) detectors. The experiment provided excellent data in γ-γ coincidences. The complex level scheme of 56Co was constructed mainly based on the analysis of these γ-γ coincidences. The angular distributions of the γ-rays were also analysed and allowed us to assign spin-parity values to most of the excited states in this nucleus. Despite the extensive work previously done studying the 56Co nucleus, the analysis presented in this work has resulted in a large improvement in the knowledge of its structure.

Clinical characteristics of Japanese diabetic patients with critical limb ischemia presenting Fontaine stage IV

The aim of the current study was to reveal the clinical characteristics of Japanese diabetic patients with critical limb ischemia (CLI) presenting ischemic unhealed ulcer/gangrene (Fontaine stage IV) in the real-world settings. The current retrospective cross-sectional study included consecutive 282 Japanese diabetic patients who underwent endovascular therapy for CLI presenting Fontaine stage IV. The prevalence of diabetes-related complications was estimated adopting multiple imputation (50 times). The patients were aged 70 ± 10 years. Median duration of diabetes was 21 (interquartile range 12-31) years. The prevalence of proliferative diabetic retinopathy, end-stage renal disease on regular dialysis, stroke, coronary artery disease, and chronic heart failure was estimated at 48% (95% confidence interval 39-56%), 52% (46-58%), 34% (28-39%), 48% (42-54%), and 35% (29-41%), respectively. The prevalence of stroke, coronary artery disease, and chronic heart failure was not significantly associated with the duration of diabetes (all p > 0.05). On the other hand, the prevalence of proliferative diabetic retinopathy and end-stage renal disease on regular dialysis was significantly positively associated with the duration of diabetes (both p < 0.05). However, these prevalences reached as high as ~ 30% even in patients with duration of diabetes < 10 years. In conclusion, the advanced stage of diabetes-related complications was prevalent in patients with CLI presenting Fontaine stage IV.

Impacts of Diabetes and an SGLT2 Inhibitor on the Glomerular Number and Volume in db/db Mice, as Estimated by Synchrotron Radiation Micro-CT at SPring-8

BACKGROUND

Recent large-scale clinical studies demonstrate that sodium-glucose cotransporter 2 (SGLT2) inhibitors protect the diabetic kidney. However, clinical and animal studies have not shown the changes of the total glomeruli in the whole kidney treated with SGLT2 inhibitors.

METHODS

We performed computed tomography (CT) imaging on mice using synchrotron radiation to investigate the impact of luseogliflozin, a SGLT2 inhibitor, on the number and volume of glomeruli in the whole kidney.

FINDINGS

We did not observe a significant difference in the total glomerular number (Nglom) among mice. Luseogliflozin redistributed the number of glomeruli in different regions, accompanied by the normalization of diabetes-augmented renal volume (Vkidney). Diabetic db/db mice had a larger glomerular volume in the mid-cortex than did control db/m mice, and luseogliflozin increased the glomerular volume in all renal cortical zones of the whole kidney in db/db mice. According to the multivariate regression analysis, hemoglobin A1c level was the most relevant determinant of Vkidney, not Nglom or mean glomerular volume (Vglom), indicating that hyperglycemia induced renal (tubular) hypertrophy, but not glomerular enlargement. Luseogliflozin increased hypoxia in the juxtamedullary region, sustained upregulated renal renin expression and plasma renin activity, and failed to decrease albuminuria by downregulating megalin in db/db mice.

INTERPRETATION

Based on our findings, SGLT2 inhibitors may alter glomerular distribution and size in addition to their glucose-lowering effects, presumably by affecting oxygen metabolism and humoral factors. FUND: Funding for this research was provided by The Japan Society for the Promotion of Science, the Japan Diabetes Foundation, and Asahikawa Medical University.