Impact of insulin and insulin resistance on brain dopamine signalling and reward processing - An underexplored mechanism in the pathophysiology of depression?

Type 2 diabetes and major depressive disorder (MDD) are the leading causes of disability worldwide and have a high comorbidity rate with fatal outcomes. Despite the long-established association between these conditions, the underlying molecular mechanisms remain unknown. Since the discovery of insulin receptors in the brain and the brain's reward system, evidence has accumulated indicating that insulin modulates dopaminergic (DA) signalling and reward behaviour. Here, we review the evidence from rodent and human studies, that insulin resistance directly alters central DA pathways, which may result in motivational deficits and depressive symptoms. Specifically, we first elaborate on the differential effects of insulin on DA signalling in the ventral tegmental area (VTA) - the primary DA source region in the midbrain - and the striatum as well as its effects on behaviour. We then focus on the alterations induced by insulin deficiency and resistance. Finally, we review the impact of insulin resistance in DA pathways in promoting depressive symptoms and anhedonia on a molecular and epidemiological level and discuss its relevance for stratified treatment strategies.

Gut⁻Liver Axis: How Do Gut Bacteria Influence the Liver?

Chronic liver diseases are a major cause of morbidity and mortality worldwide. Recently, gut dysbiosis was identified as an important factor in the pathogenesis of liver diseases. The relationship between gut microbiota and the liver is still not well understood; however, dysfunction of the gut mucosal barrier ("leaky gut") and increased bacterial translocation into the liver via the gut⁻liver axis probably play crucial roles in liver disease development and progression. The liver is an important immunological organ, and, after exposure to gut-derived bacteria via portal circulation, it responds with activation of the innate and adaptive immune system, leading to hepatic injury. A better understanding of the pathophysiological links among gut dysbiosis, the integrity of the gut barrier, and the hepatic immune response to gut-derived factors is essential for the development of new therapies to treat chronic liver diseases.

Excretion of urinary histamine and N-tele methylhistamine in patients with gastrointestinal food allergy compared to non-allergic controls during an unrestricted diet and a hypoallergenic diet.

BACKGROUND: Patients with gastrointestinal food allergy are characterised by increased production of mast cell derived mediators upon allergen contact and present often with unspecific symptoms. The aim of this study was to evaluate urinary histamine and methylhistamine excretion in patients with food allergy and to compare their values with food-tolerant controls. METHODS: In a retrospective case control study the urinary excretion parameters were analysed from 56 patients (40.9, 19 - 58 years) in whom later food challenge tests confirmed food allergy. During their diagnostic work-up urine was collected during a 12-h period under an unrestricted diet with staple foods and a hypoallergenic potato-rice-diet (each 2 days). Healthy controls underwent the same diet types to define normal excretion parameters. Urinary histamine and n-methylhistamine were determined by ELISA or tandem mass spectrometry, respectively, and were expressed as median (25 - 75% range, µg/mmol creatinine x m(2)BSA). RESULTS: During unrestricted diet urinary histamine was significantly higher in gastrointestinal food allergy than healthy controls (1.42, 0.9 - 2.7 vs 0.87, 0.4 - 1.3; p < 0.0001), while the difference between both groups became marginal during potato-rice diet (1.30, 0.7 - 2.1 vs 1.05, 0.5 - 1.5; p = 0.02). N-methylhistamine was found to be significantly elevated in gastrointestinal food allergy both during unrestricted diet (7.1, 5.0 - 11.2) and potato-rice diet (5.7, 3.7 - 8.7) compared to controls (p < 0.0001). Interestingly, urinary methylhistamine excretion (p < 0.004) and clinical symptom score (p < 0.02) fell significantly when the diet was switched from unrestricted to hypoallergenic food, but was not correlated with symptom scores. CONCLUSIONS: In gastrointestinal food allergy significantly higher levels of urine histamine and methylhistamine excretion were found under unrestricted diet, reflecting an increased secretion of histamine due to offending foods. Measurement of urinary n-methylhistamine levels may help to find out patients with increased histamine production and/or food-allergen induced clinical symptoms, respectively.

Out-of-hospital cardiac arrest and percutaneous coronary intervention for ST-elevation myocardial infarction: long-term survival and neurological outcome.

BACKGROUND: Predictors of long-term outcome after ST-elevation myocardial infarction (STEMI) complicated by out-of-hospital cardiac arrest (OHCA) are incompletely understood, including the influence of successful coronary reperfusion. METHODS: We analysed clinical and procedural data as well as 1-year outcome of 72 consecutive patients who underwent primary coronary intervention (PCI) after witnessed OHCA and STEMI and compared the results with 695 patients with STEMI and PCI, but without OHCA. Neurological recovery after OHCA was assessed using the Cerebral Performance Category (CPC) scale. RESULTS: PCI was successful in 83.3% after OHCA vs. 84.3% in the non-OHCA group (p=0.87). One-year mortality was 34.7% vs. 9.5% (p<0.001). 58.3% of the OHCA-patients showed complete neurological recovery (CPC 1) or moderate neurological disability (CPC 2). Another 6.9% showed severe cerebral disability (CPC 3) or permanent vegetative status (CPC 4). Delay from collapse until start of Advanced Cardiopulmonary Life Support (ACLS) was shorter for survivors with CPC status ≤2 (median 1 min, range 0-11 min) compared to non-survivors or survivors with CPC status >2 (median 8 min, range 0-13 min), p<0.0001. Age-adjusted multivariate analysis identified 'unsuccessful PCI', 'vasopressors on admission' and 'start of ACLS after >6 min' as independent predictors of negative long-term outcome (death or CPC >2). CONCLUSIONS: Mortality is high in patients with STEMI complicated by OHCA - even though PCI was performed with the same success rate as in patients without OHCA. The majority of survivors had favourable neurological outcomes at 1 year, especially if advanced life support had been started within ≤6 min and PCI was successful.

Strategies for training in diagnostic upper endoscopy: a prospective, randomized trial.

BACKGROUND: Training simulators have been used for decades with success; however, a standardized educational strategy for diagnostic EGD is still lacking. OBJECTIVE: Development of a training strategy for diagnostic upper endoscopy. STUDY DESIGN: Prospective, randomized trial. SETTINGS: A total of 28 medical and surgical residents without endoscopic experience were enrolled. Basic skills evaluations were performed following a structured program involving theoretical lectures and a hands-on course in diagnostic EGD. Subsequently, stratified randomization to clinical plus simulator training (group 1, n = 10), clinical training only (group 2, n = 9), or simulator training only (group 3, n = 9) was performed. Ten sessions of simulator training were conducted for groups 1 and 3 during the 4-month program. Group 2 underwent standard training in endoscopy without supplemental simulator training. The final evaluation was performed on the simulator and by observation of 3 clinical cases. Skills and procedural times were recorded by blinded and unblinded evaluators. MAIN OUTCOME MEASUREMENTS: Time to reach the duodenum, pylorus, or esophagus. RESULTS: All trainees demonstrated a significant reduction in procedure time during a simple manual skills test (P < .05) and significantly better skills scores (P = .006, P = .042 and P = .017) in the simulator independent of the training strategy. Group 1 showed shorter times to intubate the esophagus (61 ± 26 seconds vs 85 ± 30 seconds and 95 ± 36 seconds) and the pylorus (183 ± 65 seconds vs 207 ± 61 seconds and 247 ± 66 seconds) during the clinical evaluation. Blinded assessment of EGD skills showed significantly better results for group 1 compared with group 3. Blinded and unblinded evaluations were not statistically different. LIMITATIONS: Small sample size. CONCLUSIONS: Structured simulator training supplementing clinical training in upper endoscopy appears to be superior to clinical training alone. Simulator training alone does not seem to be sufficient to improve endoscopic skills.

Hemodynamic efficacy of the over-the-scope clip in an established porcine cadaveric model for spurting bleeding.

BACKGROUND: Clip application has been proven to be effective for endoscopic hemostasis. There are limited bench data on the efficacy of the over-the-scope clip (OTSC) for the treatment of spurting GI hemorrhage. We evaluated the hemodynamic efficacy of the OTSC in an established bleeding model. OBJECTIVE: To evaluate the hemodynamic efficacy of the OTSC in an established bleeding model. DESIGN: Prospective experimental trial with historical comparison. SETTING: We tested the OTSC prospectively in a validated bleeding model by using the compact Erlangen Active Simulator for Interventional Endoscopy equipped with an upper GI organ package. The artificial blood circulation system of the simulator was connected to an arterial pressure transducer. Two investigators with different endoscopic experience (4000 and 10,000 endoscopies performed) participated. Each investigator treated 16 bleeding sites in the simulator with the OTSC by using only suction (n = 8) and a novel retraction device to grasp tissue (n = 8). Systemic pressures were recorded 1 minute before, during, and 1 minute after clip application to objectify the effects of clipping on the vessel diameter. MAIN OUTCOME MEASUREMENTS: Mean and maximum reduction in vessel diameter. RESULTS: The application of the OTSC on the bleeding vessel led to a significant increase in systemic pressure (P < .001) and decreased vessel diameter (P < .001) independent of the endoscopic experience of the investigator. There was no difference in the decrease in vessel diameter based on the application technique (suction vs suction plus grasping). A historical comparison with our former trials demonstrated that the OTSC decreased the vessel diameter significantly more than other traditional endoclips. LIMITATIONS: Small sample size. CONCLUSIONS: We could demonstrate the efficacy of the OTSC with increased hemodynamic efficiency compared with other endoscopic clip devices tested previously.

Hemodynamic efficacy of sequential hemoclip application using the Olympus HX-110/610 reloadable clipping device in spurting bleedings.

BACKGROUND: Hemoclip application in GI-hemorrhage has proven to be effective. Clinical experience shows that multiple clips are frequently necessary. In 2005, an easily reloadable clip-applicator was introduced. We evaluated the hemodynamic efficacy of this new device. MATERIAL/METHODS: We prospectively compared the new clipping device (Olympus HX 110/610) in a validated experimental setting using the compactEASIE®-simulator for GI bleeding. The artificial blood circulation system in the simulator was connected to a pressure transducer. Four investigators of different endoscopic experience (1000-6000 endoscopies) treated 12 bleeding sources each, with up to 6 clips for each bleeding location. Pressures were recorded to objectify the additive effects of sequential clip application on the reduction in vessel diameter. The intervention was abandoned if a maximum measurable pressure of 300 mmHg was achieved. RESULTS: Hemoclip application led to a significant increase of peak pressure (91±100 mmHg, p<0.001) and mean pressure (95±99 mmHg, p<0.001), representing a significant reduction in vessel diameter. Pooled data showed a significant stepwise increase in mean and maximum system pressure, resulting in reduction of vessel diameter up to the fifth hemoclip. On average, 5 clips (range 1-6) were used. More experienced endoscopists achieved a higher increase in mean pressure (167 and 118 mmHg vs 72 and 23 mmHg, p<0.05). Mean reloading time was 39 seconds (19-49 sec). CONCLUSIONS: Sequential application of multiple hemoclips led to an increasing effect, comparable to the results of previous clinical trials. The number of hemoclips applied correlated inversely, but not significantly, with the endoscopist´s experience. Expensive single-use clips appear dispensable in view of the short reloading time.

Entrance barriers and integration obstacles of NOTES.

Natural orifice transluminal endoscopic surgery (NOTES) changes the paradigm of endoscopy and even surgery. The artificial perforation of abdominal hollow organs is now welcome and no longer avoided under all circumstances. Surgeons as well as gastroenterologists face a lot of problems, barriers and integration obstacles. The interdisciplinary approach for the introduction of a new technique appears promising and opens a lot of perspectives. This paper illustrates and discusses medical, technical, financial and professional barriers and integration obstacles for the introduction of NOTES into clinical practice.

Risk factors associated with adverse drug reactions following hospital admission: a prospective analysis of 907 patients in two German university hospitals.

BACKGROUND: Since the 1970s, studies have examined potential risk factors associated with adverse drug reactions (ADRs) in a variety of settings. However, no pharmacoepidemiological study exists that incorporates clinical and laboratory parameters in a multiple regression model in order to consider predictors for ADRs. OBJECTIVES: To characterize risk factors associated with ADRs in patients admitted to university hospital departments of internal medicine. DESIGN AND SETTING: Intensive pharmacovigilance was carried out in departments of internal medicine of two university hospitals. All admissions were followed prospectively for the occurrence of ADRs by members of a pharmacoepidemiological team consisting of physicians, pharmacologists and pharmacists. To identify patients at high risk for experiencing ADRs, patient histories and several clinical and laboratory data, determined at the time of admission, were taken into consideration. In addition to the drug prescribed, 40 parameters defined vital status at admission. These included temperature, heart rate, blood pressure (systolic-diastolic), body mass index, nicotine and alcohol use, and first laboratory test results after admission on nutrition status, inflammation, liver, kidney, pancreas or thyroid status, electrolytes, blood count and coagulation. RESULTS: 907 patients were observed during the study period. The mean age of the study population was 60 +/- 16 years. The median number of different drugs administered per patient during hospitalization was 9.6 +/- 7.7. In 345 patients, 592 ADRs were evaluated: 33.4% possible, 61.5% probable and 4.7% highly probable. Two ADR-related deaths were observed during the study period. Analysing ADR predictors, 17 of 40 parameters reached significance in univariate analysis, but only five in a multivariate binary regression model: raised temperature (odds ratio [OR] 1.609; 95% CI 1.133, 2.285), low erythrocyte levels (OR 0.386; 95% CI 0.194, 0.768), low thrombocyte levels (OR 0.788, 95% CI 0.627, 0.989), high number of drugs (OR 1.117; 95% CI 1.076, 1.159) and female sex (OR 1.562; 95% CI 0.785, 2.013) were independent predictors for ADRs. CONCLUSION: For the patients investigated, of the large number of clinical data available only five independent factors predict ADR occurrence. Taking these results into account, physicians will be able to focus early on patients at risk for ADRs. To minimize ADR occurrence, ADR predictors should be integrated into the clinical pathway.