Molecular targets of spermidine: implications for cancer suppression.

Spermidine is a ubiquitous, natural polyamine with geroprotective features. Supplementation of spermidine extends the lifespan of yeast, worms, flies, and mice, and dietary spermidine intake correlates with reduced human mortality. However, the crucial role of polyamines in cell proliferation has also implicated polyamine metabolism in neoplastic diseases, such as cancer. While depleting intracellular polyamine biosynthesis halts tumor growth in mouse models, lifelong external spermidine administration in mice does not increase cancer incidence. In contrast, a series of recent findings points to anti-neoplastic properties of spermidine administration in the context of immunotherapy. Various molecular mechanisms for the anti-aging and anti-cancer properties have been proposed, including the promotion of autophagy, enhanced translational control, and augmented mitochondrial function. For instance, spermidine allosterically activates mitochondrial trifunctional protein (MTP), a bipartite protein complex that mediates three of the four steps of mitochondrial fatty acid (ß-oxidation. Through this action, spermidine supplementation is able to restore MTP-mediated mitochondrial respiratory capacity in naïve CD8+ T cells to juvenile levels and thereby improves T cell activation in aged mice. Here, we put this finding into the context of the previously described molecular target space of spermidine.

Autophagy-inducing nutritional interventions in experimental and clinical oncology.

Numerous pro-autophagic dietary interventions are being investigated for their potential cancer-preventive or therapeutic effects. This applies to different fasting regimens, methionine restriction and ketogenic diets. In addition, the supplementation of specific micronutrients such as nicotinamide (vitamin B3) or spermidine induces autophagy. In humans, leanness, plant-based diets (that may lead to partial methionine restriction) and high dietary uptake of spermidine are associated with a low incidence of cancers. Moreover, clinical trials have demonstrated the capacity of nicotinamide to prevent non-melanoma skin carcinogenesis. Multiple interventional trials are evaluating the capacity of autophagy-inducing regimens to improve the outcome of chemotherapy and immunotherapy. Here, we discuss the mechanistic underpinnings of autophagy induction by nutritional interventions, as well as the mechanisms through which autophagy induction in malignant or immune cells improves anticancer immunosurveillance.

Caloric Restriction Mimetics in Nutrition and Clinical Trials.

The human diet and dietary patterns are closely linked to the health status. High-calorie Western-style diets have increasingly come under scrutiny as their caloric load and composition contribute to the development of non-communicable diseases, such as diabetes, cancer, obesity, and cardiovascular disorders. On the other hand, calorie-reduced and health-promoting diets have shown promising results in maintaining health and reducing disease burden throughout aging. More recently, pharmacological Caloric Restriction Mimetics (CRMs) have gained interest of the public and scientific community as promising candidates that mimic some of the myriad of effects induced by caloric restriction. Importantly, many of the CRM candidates activate autophagy, prolong life- and healthspan in model organisms and ameliorate diverse disease symptoms without the need to cut calories. Among others, glycolytic inhibitors (e.g., D-allulose, D-glucosamine), hydroxycitric acid, NAD+ precursors, polyamines (e.g., spermidine), polyphenols (e.g., resveratrol, dimethoxychalcones, curcumin, EGCG, quercetin) and salicylic acid qualify as CRM candidates, which are naturally available via foods and beverages. However, it is yet unclear how these bioactive substances contribute to the benefits of healthy diets. In this review, we thus discuss dietary sources, availability and intake levels of dietary CRMs. Finally, since translational research on CRMs has entered the clinical stage, we provide a summary of their effects in clinical trials.

Nicotinamide for the treatment of heart failure with preserved ejection fraction.

Heart failure with preserved ejection fraction (HFpEF) is a highly prevalent and intractable form of cardiac decompensation commonly associated with diastolic dysfunction. Here, we show that diastolic dysfunction in patients with HFpEF is associated with a cardiac deficit in nicotinamide adenine dinucleotide (NAD+). Elevating NAD+ by oral supplementation of its precursor, nicotinamide, improved diastolic dysfunction induced by aging (in 2-year-old C57BL/6J mice), hypertension (in Dahl salt-sensitive rats), or cardiometabolic syndrome (in ZSF1 obese rats). This effect was mediated partly through alleviated systemic comorbidities and enhanced myocardial bioenergetics. Simultaneously, nicotinamide directly improved cardiomyocyte passive stiffness and calcium-dependent active relaxation through increased deacetylation of titin and the sarcoplasmic reticulum calcium adenosine triphosphatase 2a, respectively. In a long-term human cohort study, high dietary intake of naturally occurring NAD+ precursors was associated with lower blood pressure and reduced risk of cardiac mortality. Collectively, these results suggest NAD+ precursors, and especially nicotinamide, as potential therapeutic agents to treat diastolic dysfunction and HFpEF in humans.

3,4-Dimethoxychalcone induces autophagy through activation of the transcription factors TFE3 and TFEB.

Caloric restriction mimetics (CRMs) are natural or synthetic compounds that mimic the health-promoting and longevity-extending effects of caloric restriction. CRMs provoke the deacetylation of cellular proteins coupled to an increase in autophagic flux in the absence of toxicity. Here, we report the identification of a novel candidate CRM, namely 3,4-dimethoxychalcone (3,4-DC), among a library of polyphenols. When added to several different human cell lines, 3,4-DC induced the deacetylation of cytoplasmic proteins and stimulated autophagic flux. At difference with other well-characterized CRMs, 3,4-DC, however, required transcription factor EB (TFEB)- and E3 (TFE3)-dependent gene transcription and mRNA translation to trigger autophagy. 3,4-DC stimulated the translocation of TFEB and TFE3 into nuclei both in vitro and in vivo, in hepatocytes and cardiomyocytes. 3,4-DC induced autophagy in vitro and in mouse organs, mediated autophagy-dependent cardioprotective effects, and improved the efficacy of anticancer chemotherapy in vivo. Altogether, our results suggest that 3,4-DC is a novel CRM with a previously unrecognized mode of action.

Caloric Restriction Mimetics against Age-Associated Disease: Targets, Mechanisms, and Therapeutic Potential.

The increase in life expectancy has boosted the incidence of age-related pathologies beyond social and economic sustainability. Consequently, there is an urgent need for interventions that revert or at least prevent the pathogenic age-associated deterioration. The permanent or periodic reduction of calorie intake without malnutrition (caloric restriction and fasting) is the only strategy that reliably extends healthspan in mammals including non-human primates. However, the strict and life-long compliance with these regimens is difficult, which has promoted the emergence of caloric restriction mimetics (CRMs). We define CRMs as compounds that ignite the protective pathways of caloric restriction by promoting autophagy, a cytoplasmic recycling mechanism, via a reduction in protein acetylation. Here, we describe the current knowledge on molecular, cellular, and organismal effects of known and putative CRMs in mice and humans. We anticipate that CRMs will become part of the pharmacological armamentarium against aging and age-related cardiovascular, neurodegenerative, and malignant diseases.

The flavonoid 4,4'-dimethoxychalcone promotes autophagy-dependent longevity across species.

Ageing constitutes the most important risk factor for all major chronic ailments, including malignant, cardiovascular and neurodegenerative diseases. However, behavioural and pharmacological interventions with feasible potential to promote health upon ageing remain rare. Here we report the identification of the flavonoid 4,4'-dimethoxychalcone (DMC) as a natural compound with anti-ageing properties. External DMC administration extends the lifespan of yeast, worms and flies, decelerates senescence of human cell cultures, and protects mice from prolonged myocardial ischaemia. Concomitantly, DMC induces autophagy, which is essential for its cytoprotective effects from yeast to mice. This pro-autophagic response induces a conserved systemic change in metabolism, operates independently of TORC1 signalling and depends on specific GATA transcription factors. Notably, we identify DMC in the plant Angelica keiskei koidzumi, to which longevity- and health-promoting effects are ascribed in Asian traditional medicine. In summary, we have identified and mechanistically characterised the conserved longevity-promoting effects of a natural anti-ageing drug.

Effects and Consequences of Being an OSCE Examiner in Surgery-A Qualitative Study.

OBJECTIVE: Even though objective structured clinical examination (OSCE) is a well-investigated format for competency-based practical examination, only a few studies have explored the motivations of OSCE examiners and their opinions, both positive and negative, toward being an examiner. The aim of this study was to gain insights into the views of OSCE examiners using semi-structured interviews. DESIGN: Surgical OSCE examiners were queried at two medical faculties in Germany via semi-structured interviews. The interviews were transcribed verbatim and analyzed using the techniques of structured qualitative content analysis. SETTING: This study was conducted at the medical faculties of the Goethe University, Frankfurt, Germany and of the Otto-von-Guericke University, Magdeburg, Germany. PARTICIPANTS: All of the study participants were surgeons working at the university hospital of one of the faculties. RESULTS: A total of 29 examiners were queried until a saturation of content was achieved. A critical reflection of one's own teaching was described as a major benefit by most participants. Furthermore, they noted that the standards and competences examined during the OSCE boosted the detail of their teaching sessions in the wards. However, the examiners criticized missed operations due the examination and were not appreciated by superiors for being an examiner. Most of the examiners (22/29) preferred to be an examiner themselves rather than appointing student peer examiners. If they had appointed someone else, that would mean they would miss valuable experiences useful for their own teaching. CONCLUSIONS: Being an OSCE examiner confers several advantages, notably the reflection of one's own teaching, which was described as highly valuable by the examiners.

Evidence for PTGER4, PSCA, and MBOAT7 as risk genes for gastric cancer on the genome and transcriptome level.

Genetic associations between variants on chromosome 5p13 and 8q24 and gastric cancer (GC) have been previously reported in the Asian population. We aimed to replicate these findings and to characterize the associations at the genome and transcriptome level. We performed a fine-mapping association study in 1926 GC patients and 2012 controls of European descent using high dense SNP marker sets on both chromosomal regions. Next, we performed expression quantitative trait locus (eQTL) analyses using gastric transcriptome data from 143 individuals focusing on the GC associated variants. On chromosome 5p13 the strongest association was observed at rs6872282 (P = 2.53 × 10-04 ) and on chromosome 8q24 at rs2585176 (P = 1.09 × 10-09 ). On chromosome 5p13 we found cis-eQTL effects with an upregulation of PTGER4 expression in GC risk allele carrier (P = 9.27 × 10-11 ). On chromosome 8q24 we observed cis-eQTL effects with an upregulation of PSCA expression in GC risk allele carrier (P = 2.17 × 10-47 ). In addition, we found trans-eQTL effects for the same variants on 8q24 with a downregulation of MBOAT7 expression in GC risk allele carrier (P = 3.11 × 10-09 ). In summary, we confirmed and refined the previously reported GC associations at both chromosomal regions. Our data point to shared etiological factors between Asians and Europeans. Furthermore, our data imply an upregulated expression of PTGER4 and PSCA as well as a downregulated expression of MBOAT7 in gastric tissue as risk-conferring GC pathomechanisms.

Yeast as a tool to identify anti-aging compounds.

In the search for interventions against aging and age-related diseases, biological screening platforms are indispensable tools to identify anti-aging compounds among large substance libraries. The budding yeast, Saccharomyces cerevisiae, has emerged as a powerful chemical and genetic screening platform, as it combines a rapid workflow with experimental amenability and the availability of a wide range of genetic mutant libraries. Given the amount of conserved genes and aging mechanisms between yeast and human, testing candidate anti-aging substances in yeast gene-deletion or overexpression collections, or de novo derived mutants, has proven highly successful in finding potential molecular targets. Yeast-based studies, for example, have led to the discovery of the polyphenol resveratrol and the natural polyamine spermidine as potential anti-aging agents. Here, we present strategies for pharmacological anti-aging screens in yeast, discuss common pitfalls and summarize studies that have used yeast for drug discovery and target identification.

The effect of written standardized feedback on the structure and quality of surgical lectures: A prospective cohort study.

BACKGROUND: Lectures remain an important teaching method to present and structure knowledge to many students concurrently. Adequate measures are necessary to maintain the quality of the lectures. The aim of this study was to determine the impact on the lecture quality using written structured feedback and to compare the ratings of surgical lectures between students and surgical peers. METHODS: Prospective analysis of two consecutive surgical lecture series for undergraduate students at Goethe-University Medical School was performed before and after evaluation of the lecturers via independent written feedback from trained undergraduate students and surgeons. The 22-item feedback instrument covered three areas of performance: content, visualization, and delivery. Additional suggestions for improvement were provided from both students and surgical peers who anonymously attended the lectures. The lecturers, experienced surgeons, as well as the student and peer raters were blinded in terms of the aim and content of the study. Their response to the feedback was collected using a web-based 13-item questionnaire. The Kendall's-W coefficient was computed to calculate inter-rater reliability (IRR). Differences between ratings before and after feedback were analyzed using Student's t-test for dependent samples. The Kolmogorov-Smirnov-test was used for independent samples. RESULTS: A total of 22 lectures from a possible 32 given by 13 lecturers were included and analyzed by at least three surgeons and two students. There were significant improvements in overall score as well as in the details of 9 of the 13 items were found. The average inter-rater reliability was 0.71. There were no differences in the ratings as a function of the rater's level of expertise (peers vs. students). We found that 13/23 lecturers (56.5%) answered the questionnaire, and 92% strongly agreed that the written feedback was useful. 76.9% of the lecturers revised their lecture based on the written feedback requiring on average 112.5 min (range from 20 to 300 min). CONCLUSIONS: Overall, this study indicates that structured written feedback provided by trained peers and students that is subsequently discussed by the lecturers concerned is a highly effective and efficient method to improve aspects of lecturing. We anticipate that structured written feedback by trained students that is discussed by the lecturers concerned will improve lecturing.

The Barrett-associated variants at GDF7 and TBX5 also increase esophageal adenocarcinoma risk.

Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) represent two stages within the esophagitis-metaplasia-dysplasia-adenocarcinoma sequence. Previously genetic risk factors have been identified that confer risk to BE and EAC development. However, to which extent the genetic variants confer risk to different stages of the BE/EAC sequence remains mainly unknown. In this study we analyzed three most recently identified BE variants at the genes GDF7 (rs3072), TBX5 (rs2701108), and ALDH1A2 (rs3784262) separately in BE and EAC samples in order to determine their risk effects during BE/EAC sequence. Our data show that rs3072 at GDF7 and rs2701108 at TBX5 are also associated with EAC and conclude that both loci confer disease risk also at later stages of the BE/EAC sequence. In contrast, rs3784262 at ALDH1A2 was highly significantly associated with BE, but showed no association with EAC. Our data do not provide evidence that the ALDH1A2 locus confers equal risk in early and late stages of BE/EAC sequence.

Supportive evidence for FOXP1, BARX1, and FOXF1 as genetic risk loci for the development of esophageal adenocarcinoma.

The Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) recently performed a genome-wide association study (GWAS) on esophageal adenocarcinoma (EAC) and Barrett's esophagus. They identified genome-wide significant association for variants at three genes, namely CRTC1, FOXP1, and BARX1. Furthermore, they replicated an association at the FOXF1 gene that has been previously found in a GWAS on Barrett's esophagus. We aimed at further replicating the association at these and other loci that showed suggestive association with P < 10(-4) in the BEACON sample. In total, we tested 88 SNPs in an independent sample consisting of 1065 EAC cases and 1019 controls of German descent. We could replicate the association at FOXP1, BARX1, and FOXF1 with nominal significance and thereby confirm that genetic variants at these genes confer EAC risk. In addition, we found association of variants near the genes XRCC2 and GATA6 that were strongly (P < 10(-5) ) although not genome-wide significantly associated with the BEACON GWAS. Therefore, both variants and corresponding genes represent promising candidates for future EAC association studies on independent samples.

Introduction of craniomaxillofacial surgery as a component of medical student training in general surgery.

PURPOSE: This study provides an overview of the objective structured clinical examination (OSCE) in concept, determination of task difficulty, execution, and evaluation by students and examiners. METHODS: During a 4-semester study period, 507 medical students completed a practical skills training (PST) course and subsequently participated in a 16-station OSCE, which contained 2 craniomaxillofacial surgical (CMS) stations covering the following key tasks: craniofacial examination and facial trauma fracture management. The students were rated using dedicated checklists. The students subjectively evaluated the PST and the OSCE using anonymous evaluation forms. RESULTS: Students rated the PST and OSCE as "very positive." The CMS OSCE stations were rated as having good task difficulty (74.05 ± 1.78% average task fulfilment for the examination and 74.45 ± 3.40% for the management station). With no changes to the examination station, no significant improvement of performance occurred over the entire investigation period (P = .787). In contrast, students improved slightly at the management station (P = .308). The CMS stations showed high selectivity and were representative in the overall context of the OSCE; improvement of selectivity increased from 0.259 ± 0.088 to 0.465 ± 0.109. CONCLUSION: CMS was successfully implemented in the general surgical training for medical students, with an initial PST and a final OSCE concordant with the literature. The CMS implementation effectively trained and fairly evaluated clinical skills. Although an OSCE consumes time and resources, this addition proved feasible and valuable, even with large numbers of students, and students expressed a high level of satisfaction with the training.

Development and implementation of an objective structured clinical examination (OSCE) in CMF-surgery for dental students.

OBJECTIVES: We introduced the OSCE (objective structured clinical examination) as a method of assessment in a problem-based learning (PBL) curriculum. The OSCE is a clinical competency test and a very good example of a practical performance (shows how) assessment instead of a theoretical written measurement (knows and knows how). The OSCE at this Department was designed to assess some of the skills that are supposedly gained during a PBL curriculum (skills such as critical thinking, problem-solving and hypothesis formation). The aim of this study was to find where the strengths and weaknesses of learning contents are during the CMF practical course and how we may raise the students' clinical competence. Furthermore we wanted to examine the possibility of achieving an OSCE with ten stations for a single department. MATERIAL AND METHODS: Students rotated through ten test stations of 5 min duration, separated by a 1 min changeover break. At each station the students' performance was observed and assessed by an examiner using a standardized multi-item checklist. All students of the eighth semester (n = 26) of the "Carolinum Dental Institute" at the University of Frankfurt were evaluated in summer 2009 in a ten station circuit of different topics, including trauma, practical knowledge and oncology. Following this all the students and examiners evaluated the OSCE. RESULTS: The overall average score was 63.2% (SD ± 8.89%). Subdivided the average results were; trauma (58.7 ± 6.79%), practical knowledge (66.1 ± 7.29%) and oncology (50 ± 4.81%). The overall rating of the OSCE was 1.69 (SD ± 0.78) for the students and 1.00 (SD ± 0) for the examiners. CONCLUSION: With good preparation, it is possible to run a ten station-OSCE circuit with ten examiners in one afternoon without interrupting patient care. The degree of difficulty was mainly acceptable. The overall average score for students' was within a range of 40-80%, which is similar to the international literature. The questionnaires showed that students and examiners viewed the new OSCE very positively.

Treatment of mandibular angle fractures - linea obliqua plate versus grid plate.

OBJECTIVES: To compare treatment outcomes, handling and long term results between two osseo-fixation systems for mandibular angle fractures - the external oblique ridge (external oblique) plate and the grid plate. MATERIAL AND METHODS: Sixty patients with mandibular angle fracture were analyzed regarding their operative treatment: 30 patients were treated with an external oblique plate and compared to 30 patients treated with a grid plate on the vestibular cortex. The follow up period was at least 1 year for both groups and the following complications were noted: infection, abnormality in fracture healing, nonunion, pain, hypoaesthesia and dysocclusion. RESULTS: The overall average operation time (from intubation to extubation) was 102.1 min (± 44.1 min). Single sided fractures treated with the grid plate needed in average 81.07 min (± 37.9 min) of operation time while single sided fractures treated with the external oblique plate needed 89.3 min (± 42.2 min). In multiple mandibular fractures, no significant change in the operation time between either plating system was found (118.8 ± 35.2 min). After the follow up period fracture healing was considered clinically complete in all patients, but complications occurred significantly more often in the external oblique group (13.3%; N=8) than in the grid plate group (0%; N=0). CONCLUSION: Isolated mandibular angle fractures can be more effectively treated using grid plates than using other osteosynthesis techniques. It is an easy to use alternative to conventional miniplate systems with good clinical outcome and fewer complications. An angulated burr and screwdriver has to be used to put on the plate laterally.

Outcome of percutaneous coronary intervention in hospitals with and without on-site cardiac surgery standby.

OBJECTIVE: To compare characteristics and outcome of patients undergoing percutaneous coronary intervention (PCI) in clinics with (WSB) or without (NOSB) on-site cardiac surgery backup. DESIGN: Analysis according to hospital, type of prospectively collected data of all patients who underwent PCI during 2000-3. SETTING: The Swedish Coronary Angiography and Angioplasty Registry covers all PCI procedures performed in Sweden. PATIENTS: 34,363 patients underwent PCI between January 2000 and December 2003. 8838 procedures were performed in NOSB (mean age of patients was 64.5 years) hospitals and 25,525 in WSB (mean age of patients was 64.1 years) hospitals (p = 0.002). RESULTS: More patients in NOSB hospitals had diabetes (17.8% vs 16.8%; p = 0.03). Other clinical characteristics (previous infarct, previous coronary artery bypass graft (CABG)) also showed a tendency towards worse patients being treated in NOSB hospitals. However, there was a higher percentage of patients with ST-segment elevation myocardial infarction (18% vs 9.7%; p<0.01) in WSB hospitals. After adjusting for differences in baseline risk no significant differences regarding outcome (30-day mortality, 1-year mortality, stroke and emergency CABG) were observable between WSB and NOSB hospitals. This applied to elective and non-elective procedures. CONCLUSIONS: On the basis of these data it does not seem warranted to recommend against percutaneous transluminal coronary angioplasty in NOSB hospitals.