MIF is a common genetic determinant of COVID-19 symptomatic infection and severity

BACKGROUND

Genetic predisposition to coronavirus disease 2019 (COVID-19) may contribute to its morbidity and mortality. Because cytokines play an important role in multiple phases of infection, we examined whether commonly occurring, functional polymorphisms in macrophage migration inhibitory factor (MIF) are associated with COVID-19 infection or disease severity.

AIM

To determine associations of common functional polymorphisms in MIF with symptomatic COVID-19 or its severity.

METHODS

This retrospective case-control study utilized 1171 patients with COVID-19 from three tertiary medical centers in the USA, Hungary and Spain, together with a group of 637 pre-pandemic, healthy control subjects. Functional MIF promoter alleles (-794 CATT5-8,rs5844572), serum MIF and soluble MIF receptor levels, and available clinical characteristics were measured and correlated with COVID-19 diagnosis and hospitalization. Experimental mice genetically engineered to express human high- or low-expression MIF alleles were studied for response to coronavirus infection.

RESULTS

In patients with COVID-19, there was a lower frequency of the high-expression MIF CATT7 allele when compared to healthy controls [11% vs. 19%, odds ratio (OR) 0.54 [0.41-0.72], P < 0.0001]. Among inpatients with COVID-19 (n = 805), there was a higher frequency of the MIF CATT7 allele compared to outpatients (n = 187) (12% vs. 5%, OR 2.87 [1.42-5.78], P = 0.002). Inpatients presented with higher serum MIF levels when compared to outpatients or uninfected healthy controls (87 ng/ml vs. 35 ng/ml vs. 29 ng/ml, P < 0.001, respectively). Among inpatients, circulating MIF concentrations correlated with admission ferritin (r = 0.19, P = 0.01) and maximum CRP (r = 0.16, P = 0.03) levels. Mice with a human high-expression MIF allele showed more severe disease than those with a low-expression MIF allele.

CONCLUSIONS

In this multinational retrospective study of 1171 subjects with COVID-19, the commonly occurring -794 CATT7MIF allele is associated with reduced susceptibility to symptomatic SARS-CoV-2 infection but increased disease progression as assessed by hospitalization. These findings affirm the importance of the high-expression CATT7MIF allele, which occurs in 19% of the population, in different stages of COVID-19 infection.

Gyermekkori, áramégés okozta kézujjsérülések ellátásáról és késői szövődményeiről

Összefoglaló. Elektromos áram okozta égési sérülések gyermekkorban ritkán fordulnak elő, az összes égés mindössze 2-10%-át teszik ki. Nehézséget okozhat a sérülés valódi súlyosságának meghatározása a kicsiny ki- és bemeneti sebek miatt. Áramégések során a legtöbb esetben mély necrosis alakul ki. Ilyen sérülések esetén a bőr, a lágy részek, a csontok, illetve fiatal életkorban a növekedési zóna sérülésével is számolni kell, ami növekedési zavart és ezáltal másodlagos deformitásokat okozhat. Jelen esettanulmányunk célja az áramégés során létrejött gyermekkori kézujjsérülések ellátásának és késői szövődményeinek bemutatása. Egy 15 éves fiúgyermek izzócsere közben ráfogott egy vezetékre, ami a jobb mutatóujján égési sérülést okozott. Distalis interphalangealis ízülete felett volarisan 25 × 14 milliméter nagyságú bemeneti, dorsalisan a körömágy lateralis szélén 8 × 7 milliméteres kimeneti áramjegy volt látható fehér, necroticus sebalappal, mely III . fokú égési sérülésnek bizonyult. A mély égési sérülés miatt necrectomia, keresztlebeny-plasztika és az adóterület teljes vastagságú bőrrel végzett transzplantálása történt. A primer rekonstrukciót követően három héttel a lebeny leválasztására került sor. A nyomon követés során a mutatóujj körömperc-deviációja volt észlelhető. A röntgenvizsgálat a körömpercbázis ízfelszínét is érintő csonthiányt igazolt. Egy 2 éves leánygyermek szöggel nyúlt a konnektorba, emiatt hüvelykujján és tenyerén keletkezett égési sérülés. Interphalangealis ízülete felett dorsalisan és volarisan, valamint a hypothenar területén III. fokú égési sérülés volt látható. Necrectomiát követően a hüvelykujj ventralis bőrdefektusának zárása elforgatott lebennyel, a donorterület és a dorsalis bőrdefektus fedése teljes vastagságú bőrrel történt. A gyermek nyomon követése jelenleg is zajlik, rövid távon a csontérintettség okozta végperc-deviáció látható. A gyermekek hosszú távú nyomon követése szükséges a késői szövődmények felismerése és kezelése céljából. Orv Hetil. 2022; 163(14): 564-568. Summary. Pediatric electrical injuries are rare; they only constitute 2-10% of all burn causes. Determination of their actual severity may be challenging due to their small entry and exit wounds. Deep necrosis develops during electrical burns in most cases. These injuries can damage the skin, soft and bone tissues, and in children, the growth plate, which may cause secondary deformities. The objective of these case reports was the presentation of paediatric electrical finger injuries' management and late-onset complications. A 15-year-old boy touched an electric wire while changing a lightbulb, which caused a burn injury on his right index finger. During the physical examination, a 25 × 14 mm, third-degree burn was identified volarly, above the distal interphalangeal joint as an entry wound, and an 8 × 7 mm exit site occurred dorsally at the nailbed's lateral edge. Necrectomy and cross finger flap surgery were performed. The cross flap was separated three weeks after the primary reconstruction. Throughout the follow-up examinations, the ulnar deviation of the distal digit was observed. X-ray confirmed the bone atrophy of the distal phalanx base. A 2-year-old girl inserted a nail into the power outlet, causing third-degree burns on her thumb around the interphalangeal joint and hypothenar region. After necrectomy, the thumb's skin defect was reconstructed with a rotated flap, while the donor site received full-thickness skin graft transplantation. The follow-up of the child is still ongoing. Long term follow-up of these patients is necessary to identify and treat late-onset complications. Orv Hetil. 2022; 163(14): 564-568.

Efficacy of Treatments in Nonarteritic Ischemic Optic Neuropathy: A Systematic Review and Meta-Analysis

Background: Nonarteritic Anterior Ischemic Optic Neuropathy (NAION) is the second most common cause of optic nerve-related permanent visual loss in adults. Aim: We aimed to analyze the efficacy of the noninvasive and minimally invasive therapeutic options of NAION. Methods: We performed a systematic literature search in MEDLINE, EMBASE, and CENTRAL from inception to 10 June 2019 to identify the studies that report on the effect of different therapies on visual acuity (VA) and visual field (VF). Weighted mean difference (WMD) with 95% confidence interval (CI) was calculated for these outcomes. The efficacy of steroids was investigated in quantitative, oxygen, steroid plus erythropoietin (EPO), levodopa/carbidopa, memantine, and heparin-induced extracorporeal LDL/fibrinogen precipitation (HELP) therapies and other therapeutic modalities in qualitative synthesis. Results: Thirty-two studies were found to be eligible. We found that steroid therapy compared to control did not improve VA (p = 0.182, WMD = 0.14, 95% CI: −0.07, 0.35) or VF (p = 0.853, WMD = 0.16, 95% CI: −1.54, 1.86). Qualitative analysis could be performed for oxygen, steroid plus EPO, and HELP as well, however, none of them showed VA and VF benefit. Two individual studies found memantine and levodopa beneficial regarding VA. Conclusion: Our systematic review did not reveal any effective treatment. Further investigations are needed to find therapy for NAION.

Weight reduction added to CPAP decreases blood pressure and triglyceride level in OSA: systematic review and meta-analysis

Obstructive sleep apnea (OSA) is associated with treatment‐resistant hypertension and high cardiovascular risk. Continuous positive airway pressure (CPAP) fails to reduce cardiovascular risks consistently. Obesity and OSA show reciprocal association and they synergistically increase hypertension via different pathways. Our meta‐analysis aimed to assess the cardiovascular benefits of combining weight loss (WL) with CPAP (vs. WL or CPAP alone) in OSA. Outcomes included systolic and diastolic blood pressure (BP) and blood lipid parameters. We explored Medline, Embase, Cochrane, and Scopus. Eight randomized controlled studies (2627 patients) were included. The combined therapy decreased systolic BP more than CPAP alone. Weighted mean difference (WMD) for CPAP + WL versus CPAP was −8.89 mmHg, 95% confidence interval (95% CI; −13.67 to −4.10, p < 0.001) for systolic BP. For diastolic BP, this decrease was not significant. In case of blood lipids, the combined treatment decreased triglyceride levels more than CPAP alone (WMD = −0.31, 95% CI −0.58 to −0.04, p = 0.027). On the other hand, addition of CPAP to WL failed to suppress BP further. The certainty of evidence according to GRADE was very low to moderate. In conclusion, our results showed that the addition of WL to CPAP significantly improved BP and blood lipid values in OSA. On the other hand, the addition of CPAP to WL could not significantly improve BP or blood lipid values. Review protocol: PROSPERO CRD42019138998.

Inflammatory Biomarkers Are Inaccurate Indicators of Bacterial Infection on Admission in Patients With Acute Exacerbation of Chronic Obstructive Pulmonary Disease-A Systematic Review and Diagnostic Accuracy Network Meta-Analysis

Introduction: The value of inflammatory biomarkers in the diagnosis of bacterial infection induced acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is currently unclear. Our objective was to investigate the diagnostic accuracy of on-admission inflammatory biomarkers in differentiating bacterial origin in AECOPD.

Methods: Systematic literature search was performed to include cross-sectional studies on AECOPD patients with microbiological culture results as gold standard, and at least one on-admission inflammatory biomarker determined from serum: C-reactive protein (CRP), procalcitonin (PCT), neutrophil/lymphocyte ratio, eosinophil percentage, CD64index; or sputum: neutrophil elastase, tumor necrosis factor alfa, interleukin-1-beta (IL-1b), interleukin-8, sputum color, as index tests. We ranked index tests by superiority indices in a network meta-analysis and also calculated pooled sensitivity and specificity.

Results: Altogether, 21 eligible articles reported data on 2,608 AECOPD patients (44% bacterial). Out of the 14 index tests, sputum IL-1b showed the highest diagnostic performance with a pooled sensitivity of 74% (CI: 26–97%) and specificity of 65% (CI: 19–93%). Pooled sensitivity for CRP and PCT were: 67% (CI: 54–77%) and 54% (CI: 39–69%); specificity 62% (CI: 52–71%) and 71% (CI: 59–79%), respectively.

Conclusion: Admission inflammatory biomarkers are inaccurate indicators of bacterial infection in AECOPD.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/#myprospero, identifier: 42020161301.

Pediatric deep burn management after split-thickness autologous skin transplantation: A comparative study

Treatment of pediatric deep burns remains a challenge for healthcare personnel. After skin grafting, several treatment options are available, but comparative studies of the different options are scarce. Here, we compared the effectiveness of 2 postoperative dressings used to treat deep pediatric burns after split-thickness skin grafting.At the Department of Paediatrics, University of Pécs, 16 children received skin transplantation after the deep second and third-degree injuries between January 1, 2012 and December 31, 2020 whose results have been analyzed, in this cohort study. We compared the traditionally used Grassolind or Mepitel net and Betadine solution (comparison group) with Aquacel Ag foam and Curiosa gel (intervention group).Seven children were included in the comparison and 9 children in the intervention group. In the control group, the average number of anesthesia was 6.29, while the number of dressing changes was 4.29. After complete wound closure, the dressing's final removal was on the 13th day, while the mean length of hospitalization was 21.89 days. On average, in the intervention group, 3.56 anesthesia was induced, and 0.66 dressing changes were needed after transplantation. Complete healing (dressing removal) was on the 10th day, and the mean length of hospitalization was 12.38 days.In the intervention group, the need for anesthesia significantly decreased by 43% (P = .004), and they required 84% fewer dressing changes after transplantation (P = .001). Moreover, the dressing could be removed 3 days earlier, and the length of hospitalization was reduced by 45% on average.

Increased risk of adverse events in patients with low-on clopidogrel platelet reactivity after percutaneous coronary intervention: A systematic review and meta-analysis

BACKGROUND

Clinical evidence has been controversial regarding the influence of low platelet reactivity (LPR), ischemic and bleeding outcomes among patients receiving coronary stent implantation. Hence, the present study performed a meta-analysis to systematically evaluate the significance of LPR on adverse cardiovascular events.

METHODS

MEDLINE, EMBASE and CENTRAL databases were searched up to November 2020 for relevant studies including patients with acute coronary syndrome undergoing percutaneous coronary intervention. LPR was the exposed arm while the non-LPR group represented the control. The primary outcome of interest was bleeding risk including major and minor bleeding events. Secondary outcomes included all-cause mortality, repeated revascularization, nonfatal myocardial infarction, and stent thrombosis. Study-level outcomes were evaluated in random-effect models.

RESULTS

A total of 20 studies with 19,064 patients were included. Pooled analysis showed that LPR was associated with an increased bleeding risk (relative risk [RR] 2.80, 95% confidence interval [CI] 1.95-4.02, p < 0.01). Patients with LPR had a lower risk of non-fatal myocardial infarction (RR 0.59, 95% CI 0.38-0.91, p < 0.05) and of serious vascular events (RR 0.50, 95% CI 0.30-0.84, p < 0.01).

CONCLUSIONS

LPR is associated with an increased bleeding risk of patients who underwent coronary stent implantation. The results suggest possible benefits of this marker in risk stratification, with potential improvement in risk prediction. There are potential advantages using combinations with other factors in prediction models, however, they require further study. PROSPERO registration number: CRD42019136393).

Tetralone derivatives are MIF tautomerase inhibitors and attenuate macrophage activation and amplify the hypothermic response in endotoxemic mice

Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine playing crucial role in immunity. MIF exerts a unique tautomerase enzymatic activity that has relevance concerning its multiple functions and its small molecule inhibitors have been proven to block its pro-inflammatory effects. Here we demonstrate that some of the E-2-arylmethylene-1-tetralones and their heteroanalogues efficiently bind to MIF's active site and inhibit MIF tautomeric (enolase, ketolase activity) functions. A small set of the synthesised derivatives, namely compounds (4), (23), (24), (26) and (32), reduced inflammatory macrophage activation. Two of the selected compounds (24) and (26), however, markedly inhibited ROS and nitrite production, NF-κB activation, TNF-α, IL-6 and CCL-2 cytokine expression. Pre-treatment of mice with compound (24) exaggerated the hypothermic response to high dose of bacterial endotoxin. Our experiments suggest that tetralones and their derivatives inhibit MIF's tautomeric functions and regulate macrophage activation and thermal changes in severe forms of systemic inflammation.

Proof-of-Concept for the Analgesic Effect and Thermoregulatory Safety of Orally Administered Multi-Target Compound SZV 1287 in Mice: A Novel Drug Candidate for Neuropathic Pain

SZV 1287 (3-(4,5-diphenyl-1,3-oxazol-2-yl)propanal oxime) is a novel multi-target candidate under preclinical development for neuropathic pain. It inhibits amine oxidase copper containing 3, transient receptor potential ankyrin 1 and vanilloid 1 (TRPV1) receptors. Mainly under acidic conditions, it is transformed to the cyclooxygenase inhibitor oxaprozin, which is ineffective for neuropathy. Therefore, an enterosolvent capsule is suggested for oral formulation, which we investigated for nociception, basic kinetics, and thermoregulatory safety in mice. The antihyperalgesic effect of SZV 1287 (10, 20, 50, and 200 mg/kg, p.o.) was determined in partial sciatic nerve ligation-induced traumatic neuropathy by aesthesiometry, brain and plasma concentrations by HPLC, and deep body temperature by thermometry. Its effect on proton-induced TRPV1 activation involved in thermoregulation was assessed by microfluorimetry in cultured trigeminal neurons. The three higher SZV 1287 doses significantly, but not dose-dependently, reduced neuropathic hyperalgesia by 50% of its maximal effect. It was quickly absorbed; plasma concentration was stable for 2 h, and it entered into the brain. Although SZV 1287 significantly decreased the proton-induced TRPV1-mediated calcium-influx potentially leading to hyperthermia, it did not alter deep body temperature. Oral SZV 1287 inhibited neuropathic hyperalgesia and, despite TRPV1 antagonistic action and brain penetration, it did not influence thermoregulation, which makes it a promising analgesic candidate.

Efficacy of Biologics Targeting Tumour Necrosis Factor-alpha, Interleukin-17 -12/23, -23 and Small Molecules Targeting JAK and PDE4 in the Treatment of Nail Psoriasis: A Network Meta-analysis

The comparative efficacy of registered anti-psoriatic biologics and small molecules in treating nail symptoms has not been systematically evaluated. The aim of this study was to perform a network meta-analysis to determine the efficacy of biologics and small molecules in nail psoriasis. A Bayesian network meta-analysis of 17 randomized clinical trials (a total of 6,053 nail psoriatic patients) was performed, comparing the short-term (week 10–16) efficacy of biologics and small molecules in the treatment of nail psoriasis. All active treatments were found to be superior to placebo. Ixekizumab 80 mg every 4 weeks (Nail Psoriasis Severity Index (NAPSI) % improvement, Surface Under the Cumulative Ranking (SUCRA)=0.92) and etanercept 50 mg twice weekly (probability of achieving NAPSI 50, SUCRA=0.82) proved the best short-term treatment options. However, efficacy end-points in psoriasis trials were not optimized for nail assessment, and outcome parameters were highly heterogeneous, limiting comparability. In conclusion, outcome parameters and efficacy endpoints of nail psoriasis trials should be standardized.

Probiotics have beneficial metabolic effects in patients with type 2 diabetes mellitus: a meta-analysis of randomized clinical trials

Probiotics have been reported to have a positive impact on the metabolic control of patients with type 2 diabetes. We aimed to systematically evaluate the effects of probiotics on cardiometabolic parameters in type 2 diabetes based on randomized controlled studies. MEDLINE, Embase, and CENTRAL databases were reviewed to search for randomized controlled trials that examined the effects of probiotic supplementation on cardiometabolic parameters in patients with type 2 diabetes. 32 trials provided results suitable to be included in the analysis. The effects of probiotics were calculated for the following parameters: BMI, total cholesterol levels, LDL, triglycerides, HDL, CRP, HbA1c levels, fasting plasma glucose, fasting insulin levels, systolic and diastolic blood pressure values. Data analysis showed a significant effect of probiotics on reducing total cholesterol, triglyceride levels, CRP, HbA1c, fasting plasma glucose, fasting insulin levels, and both systolic and diastolic blood pressure values. Supplementation with probiotics increased HDL levels however did not have a significant effect on BMI or LDL levels. Our data clearly suggest that probiotics could be a supplementary therapeutic approach in type 2 diabetes mellitus patients to improve dyslipidemia and to promote better metabolic control. According to our analysis, probiotic supplementation is beneficial in type 2 diabetes mellitus.

Maternal overnutrition impairs offspring's insulin sensitivity: A systematic review and meta-analysis

This systematic review and meta‐analysis aimed to investigate the association between maternal overnutrition and offspring's insulin sensitivity—following the Preferred Reporting Items for Systematic Reviews and Meta‐analyses statement. Studies published in English before April 22, 2019, were identified through searches of four medical databases. After selection, 15 studies aiming to explore the association between prepregnancy body mass index (ppBMI) or gestational weight gain (GWG) of non‐diabetic mothers and their offspring's insulin sensitivity (fasting insulin or glucose level and Homeostatic Measurement Assessment for Insulin Resistance [HOMA‐IR]) were included in the meta‐analysis. Associations of ppBMI and GWG with offspring's insulin sensitivity were analysed by pooling regression coefficients or standardized differences in means with 95% confidence intervals (CIs). Maternal ppBMI showed significant positive correlations with the level of both fasting insulin and HOMA‐IR in offspring (standardized regression coefficient for fasting insulin: 0.107, CI [0.053, 0.160], p < 0.001 and that for HOMA‐IR: 0.063, CI [0.006, 0.121], p = 0.031). However, the result of the analysis on coefficients adjusted for offspring's actual anthropometry (BMI and adiposity) was not significant. Independent from ppBMI, GWG tended to show a positive correlation with insulin level, but not after adjustment for offspring's anthropometry. Offspring of mothers with excessive GWG showed significantly higher HOMA‐IR than those of mothers with optimal GWG (p = 0.004). Our results demonstrate that both higher ppBMI and GWG increase the risk of offspring's insulin resistance, but the effect of ppBMI on insulin sensitivity in offspring may develop as consequence of their adiposity.

Computed Tomography Severity Index vs. Other Indices in the Prediction of Severity and Mortality in Acute Pancreatitis: A Predictive Accuracy Meta-analysis

Background: The management of the moderate and severe forms of acute pancreatitis (AP) with necrosis and multiorgan failure remains a challenge. To predict the severity and mortality of AP multiple clinical, laboratory-, and imaging-based scoring systems are available. Aim: To investigate, if the computed tomography severity index (CTSI) can predict the outcomes of AP better than other scoring systems. Methods: A systematic search was performed in three databases: Pubmed, Embase, and the Cochrane Library. Eligible records provided data from consecutive AP cases and used CTSI or modified CTSI (mCTSI) alone or in combination with other prognostic scores [Ranson, bedside index of severity in acute pancreatitis (BISAP), Acute Physiology, and Chronic Health Examination II (APACHE II), C-reactive protein (CRP)] for the evaluation of severity or mortality of AP. Area under the curves (AUCs) with 95% confidence intervals (CIs) were calculated and aggregated with STATA 14 software using the metandi module. Results: Altogether, 30 studies were included in our meta-analysis, which contained the data of 5,988 AP cases. The pooled AUC for the prediction of mortality was 0.79 (CI 0.73-0.86) for CTSI; 0.87 (CI 0.83-0.90) for BISAP; 0.80 (CI 0.72-0.89) for mCTSI; 0.73 (CI 0.66-0.81) for CRP level; 0.87 (CI 0.81-0.92) for the Ranson score; and 0.91 (CI 0.88-0.93) for the APACHE II score. The APACHE II scoring system had significantly higher predictive value for mortality than CTSI and CRP (p = 0.001 and p < 0.001, respectively), while the predictive value of CTSI was not statistically different from that of BISAP, mCTSI, CRP, or Ranson criteria. The AUC for the prediction of severity of AP were 0.80 (CI 0.76-0.85) for CTSI; 0.79, (CI 0.72-0.86) for BISAP; 0.83 (CI 0.75-0.91) for mCTSI; 0.73 (CI 0.64-0.83) for CRP level; 0.81 (CI 0.75-0.87) for Ranson score and 0.80 (CI 0.77-0.83) for APACHE II score. Regarding severity, all tools performed equally. Conclusion: Though APACHE II is the most accurate predictor of mortality, CTSI is a good predictor of both mortality and AP severity. When the CT scan has been performed, CTSI is an easily calculable and informative tool, which should be used more often in routine clinical practice.

Lactose intolerance but not lactose maldigestion is more frequent in patients with irritable bowel syndrome than in healthy controls: A meta-analysis

BACKGROUND AND PURPOSE

Irritable bowel syndrome (IBS) affects 10%-20% of the adult population and is characterized by abdominal symptoms without relevant organic disease. There are numerous clinical trials available investigating the relationship between IBS, lactose maldigestion (LM), and lactose intolerance (LI), but there have been no meta-analyses on this topic yet. We aimed to assess the prevalence of LM, objective and subjective (self-reported) LI in IBS patients compared to healthy controls (HC) without IBS.

METHODS

A systematic literature search was conducted up to 24 April 2018 in PubMed, Embase, and Cochrane Library. Adult IBS patients had to be diagnosed according to the Rome criteria or other well-defined criteria system. We enrolled controlled studies including healthy adult participants without IBS, as control group. Odds ratios with 95% confidence intervals were calculated.

KEY RESULTS

Altogether 14 articles were suitable for statistical analyses. IBS patients reported themselves significantly more frequently lactose intolerant than HCs (odds ratio [OR] = 3.499; 95% confidence interval [CI] = 1.622-7.551). Generally, there was no significant difference in the prevalence of LM based on ingested lactose dose (OR = 1.122; 95% CI = 0.929-1.356) and test type (OR = 1.156; 95% CI = 0.985-1.356). However, significantly more IBS patients had objective LI (OR = 2.521; 95% CI = 1.280-4.965).

CONCLUSIONS AND INFERENCES

Lactose intolerance, but not LM is more frequent among patients with IBS compared to HCs. According to our results, IBS among other functional bowel disorders is a possible contributing factor of LI in people with LM.

Metformin induces significant reduction of body weight, total cholesterol and LDL levels in the elderly - A meta-analysis

Background

Metformin is the first-choice drug for patients with Type 2 diabetes, and this therapy is characterized by being weight neutral. However, in the elderly an additional unintentional weight loss could be considered as an adverse effect of the treatment.

Objectives

We aimed to perform a meta-analysis of placebo-controlled studies investigating the body weight changes upon metformin treatment in participants older than 60 years.

Materials and methods

PubMed, EMBASE and the Cochrane Library were searched. We included at least 12 week-long studies with placebo control where the mean age of the metformin-treated patients was 60 years or older and the body weight changes of the patients were reported. We registered our protocol on PROSPERO (CRD42017055287).

Results

From the 971 articles identified by the search, 6 randomized placebo-controlled studies (RCTs) were included in the meta-analysis (n = 1541 participants). A raw difference of -2.23 kg (95% CI: -2.84 –-1.62 kg) body weight change was detected in the metformin-treated groups as compared with that of the placebo groups (p<0.001). Both total cholesterol (-0.184 mmol/L, p<0.001) and LDL cholesterol levels (-0.182 mmol/L, p<0.001) decreased upon metformin-treatment.

Conclusions

Our meta-analysis of RCTs showed a small reduction of body weight together with slight improvement of the blood lipid profile in patients over 60 years. With regard to the risk of unintentional weight loss, metformin seems to be a safe agent in the population of over 60 years. Our results also suggest that metformin treatment may reduce the risk of major coronary events (-4-5%) and all-cause mortality (-2%) in elderly diabetic populations.

Perceived stress correlates with visceral obesity and lipid parameters of the metabolic syndrome: A systematic review and meta-analysis

BACKGROUND

Perceived stress has been proposed as a risk factor of metabolic syndrome. However, correlations between perceived stress and parameters of the metabolic syndrome have not been properly analyzed despite extensive research data on the topic. Our current meta-analysis aimed to examine the mutual association between perceived stress of patients and parameters of metabolic syndrome.

METHODS

This systematic review has been registered on the PROSPERO database (registration number CRD42017055293). Eligible studies divided participants based on their stress level or on the presence of metabolic syndrome. They reported at least one parameter of the metabolic syndrome or the stress level of the participants measured with some stress scale. Data from 17 articles met the eligibility criteria and were included. Random effects model with the DerSimonian and Laird weighting methods was applied. I-squared indicator and Q test were performed to assess heterogeneity.

RESULTS

Although the majority of individual studies failed to demonstrate correlations between stress and their analyzed parameters of metabolic syndrome, our meta-analysis showed a significant association between stress and BMI [average effect size (ES) with 95% confidence interval (95%CI), ES = 0.65, 95%CI 0.16, 1.14), waist circumference (ES = 1.84 cm, 95%CI 0.79, 2.89) and serum triglyceride level (ES = 7.52 mg/dl, 95%CI 0.07, 14.96). Additional analysis confirmed effects of stress on serum HDL (ES = - 1.699 mg/dl, 95%CI -2.966, -0.432) and diastolic blood pressure (ES = 1.04 mmHg, 95%CI 0.18, 1.89). No correlations were found for fasting glucose or systolic blood pressure. No association between metabolic syndrome and stress level of patients was detected either.

CONCLUSION

The potentially key role of visceral obesity in the association between perceived stress and dyslipidemia or diastolic blood pressure are discussed together with potential moderators (e.g. gender-differences, variations in stress assessment and metabolic syndrome criteria) that may explain the inconsistent, contradictory results of the individual studies.

Helicobacter pylori infection reduces the risk of Barrett's esophagus: A meta-analysis and systematic review

INTRODUCTION

The prevalence of Helicobacter pylori infection (HPI) has been decreasing in developed countries, with an increasing prevalence of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) at the same time. The aim of our meta-analysis was to quantify the risk of BE in the context of HPI.

METHODS

A systematic search was conducted in 3 databases for studies on BE with data on prevalence of HPI from inception until December 2016. Odds ratios for BE in HPI were calculated by the random effects model with subgroup analyses for geographical location, presence of dysplasia in BE, and length of the BE segment.

RESULTS

Seventy-two studies were included in the meta-analysis, including 84 717 BE cases and 390 749 controls. The overall analysis showed that HPI reduces the risk of BE; OR = 0.68 (95% CI: 0.58-0.79, P < .001). Subgroup analyses revealed risk reduction in Asia OR = 0.53 (95% CI: 0.33-0.84, P = .007), Australia OR = 0.56 (95% CI: 0.39-0.80, P = .002), Europe OR = 0.77 (95% CI: 0.60-0.98, P = .035), and North-America OR = 0.59 (95% CI: 0.47-0.74, P < .001). The risk was significantly reduced for dysplastic BE, OR = 0.37 (95% CI: 0.26-0.51, P < .001) for non-dysplastic BE, OR = 0.51 (95% CI: 0.35-0.75, P = .001), and for long segment BE, OR = 0.25 (95% CI: 0.11-0.59, P = .001) in case of HPI.

CONCLUSIONS

This extensive meta-analysis provides additional evidence that HPI is associated with reduced risk of BE. Subgroup analyses confirmed that this risk reduction is independent of geographical location. HPI is associated with significantly lower risk of dysplastic, non-dysplastic, and long segment BE.

TRPV1 antagonists that cause hypothermia, instead of hyperthermia, in rodents: Compounds' pharmacological profiles, in vivo targets, thermoeffectors recruited and implications for drug development

AIM

Thermoregulatory side effects hinder the development of transient receptor potential vanilloid-1 (TRPV1) antagonists as new painkillers. While many antagonists cause hyperthermia, a well-studied effect, some cause hypothermia. The mechanisms of this hypothermia are unknown and were studied herein.

METHODS

Two hypothermia-inducing TRPV1 antagonists, the newly synthesized A-1165901 and the known AMG7905, were used in physiological experiments in rats and mice. Their pharmacological profiles against rat TRPV1 were studied in vitro.

RESULTS

Administered peripherally, A-1165901 caused hypothermia in rats by either triggering tail-skin vasodilation (at thermoneutrality) or inhibiting thermogenesis (in the cold). A-1165901-induced hypothermia did not occur in rats with desensitized (by an intraperitoneal dose of the TRPV1 agonist resiniferatoxin) sensory abdominal nerves. The hypothermic responses to A-1165901 and AMG7905 (administered intragastrically or intraperitoneally) were absent in Trpv1^-/- mice, even though both compounds evoked pronounced hypothermia in Trpv1^+/+ mice. In vitro, both A-1165901 and AMG7905 potently potentiated TRPV1 activation by protons, while potently blocking channel activation by capsaicin.

CONCLUSION

TRPV1 antagonists cause hypothermia by an on-target action: on TRPV1 channels on abdominal sensory nerves. These channels are tonically activated by protons and drive the reflectory inhibition of thermogenesis and tail-skin vasoconstriction. Those TRPV1 antagonists that cause hypothermia further inhibit these cold defences, thus decreasing body temperature.

SIGNIFICANCE

TRPV1 antagonists (of capsaicin activation) are highly unusual in that they can cause both hyper- and hypothermia by modulating the same mechanism. For drug development, this means that both side effects can be dealt with simultaneously, by minimizing these compounds' interference with TRPV1 activation by protons.

Gender difference in the effects of interleukin-6 on grip strength - a systematic review and meta-analysis

Background

Aging sarcopenia characterized by low muscle mass with low muscle strength affects men and women differently. The contribution of interleukin-6 (IL-6) to sarcopenia has been suggested based on a negative correlation between plasma IL-6 and muscle function described by some studies. However, no consensus regarding clinically relevant cut-off criteria has been reached. Another question arises whether pooling male and female data is an accurate way to determine the predictive value of IL-6 in sarcopenia. The present meta-analysis was designed to assess: (1) whether plasma IL-6 in aged populations in fact correlates negatively to muscle strength; (2) whether such a correlation exists both in men and in women; and (3) whether plasma IL-6 shows a gender difference in old age.

Methods

We applied the preferred reporting items for systematic review and meta-analysis protocols (PRISMA). We searched PubMed and Embase for papers that reported data on individuals over 65 without inflammatory diseases. We extracted either separate male and female data on plasma IL-6 along with at least one muscle parameter or correlation coefficient between plasma IL-6 and these parameters. Random effect models calculated with DerSimonian and Laird weighting methods were applied to analyze correlation coefficients and gender difference in plasma IL-6. Egger’s test was used to assess the small study effect.

Results

Twenty articles out of 468 records identified were suitable for analyses. Plasma IL-6 correlates negatively with grip strength in mixed populations and also separately in men [− 0.25 with 95% confidence interval (CI): − 0.48, − 0.02] and in women (− 0.14 with 95% CI: − 0.24, − 0.03). However, contrary to expectations, men with better muscle condition have higher plasma IL-6 than women of similar age with worse muscle condition (plasma IL-6 male–female difference: 0.25 pg/mL with 95% CI: 0.15, 0.35).

Conclusion

This is the first study to demonstrate that a higher predictive IL-6 cut-off level should be determined for aging sarcopenia in men than in women.

Electronic supplementary material

The online version of this article (10.1186/s12877-018-0798-z) contains supplementary material, which is available to authorized users.

Compared efficacy of preservation solutions on the outcome of liver transplantation: Meta-analysis

AIM

To compare the effects of the four most commonly used preservation solutions on the outcome of liver transplantations.

METHODS

A systematic literature search was performed using MEDLINE, Scopus, EMBASE and the Cochrane Library databases up to January 31st, 2017. The inclusion criteria were comparative, randomized controlled trials (RCTs) for deceased donor liver (DDL) allografts with adult and pediatric donors using the gold standard University of Wisconsin (UW) solution or histidine-tryptophan-ketoglutarate (HTK), Celsior (CS) and Institut Georges Lopez (IGL-1) solutions. Fifteen RCTs (1830 livers) were included; the primary outcomes were primary non-function (PNF) and one-year post-transplant graft survival (OGS-1).

RESULTS

All trials were homogenous with respect to donor and recipient characteristics. There was no statistical difference in the incidence of PNF with the use of UW, HTK, CS and IGL-1 (RR = 0.02, 95%CI: 0.01-0.03, P = 0.356). Comparing OGS-1 also failed to reveal any difference between UW, HTK, CS and IGL-1 (RR = 0.80, 95%CI: 0.80-0.80, P = 0.369). Two trials demonstrated higher PNF levels for UW in comparison with the HTK group, and individual studies described higher rates of biliary complications where HTK and CS were used compared to the UW and IGL-1 solutions. However, the meta-analysis of the data did not prove a statistically significant difference: the UW, CS, HTK and IGL-1 solutions were associated with nearly equivalent outcomes.

CONCLUSION

Alternative solutions for UW yield the same degree of safety and effectiveness for the preservation of DDLs, but further well-designed clinical trials are warranted.

Transpancreatic sphincterotomy has a higher cannulation success rate than needle-knife precut papillotomy - a meta-analysis

Background and aim While many studies have discussed the different cannulation techniques used in patients with difficult biliary access, no previous meta-analyses have compared transpancreatic sphincterotomy (TPS) to other advanced techniques. Therefore, we aimed to identify all studies comparing the efficacy and adverse event rates of TPS with needle-knife precut papillotomy (NKPP), the most commonly used technique, and to perform a meta-analysis. Methods The Embase, PubMed, and Cochrane databases were searched for trials comparing the outcomes of TPS with NKPP up till December 2016. A meta-analysis focusing on outcome (cannulation success, post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP), post-procedural bleeding, and total adverse events) was performed. The population, intervention, comparison, outcome (PICO) format was used to compare these cannulation approaches. Five prospective and eight retrospective studies were included in our meta-analysis. Results NKPP has a significantly lower success rate (odds ratio [OR] 0.50, P = 0.046; relative risk [RR] 0.92, P = 0.03) and a higher rate of bleeding complications (OR 2.24, P = 0.02; RR 2.18, P = 0.02) than TPS. However, no significant differences were found in PEP (OR 0.79, P = 0.24; RR 0.80, P = 0.19), perforation (risk difference [RD] 0.01, P = 0.23), or total complication rates (OR 1.22, P = 0.44; RR 1.17, P = 0.47). Conclusion While TPS has a higher success rate in difficult biliary access and causes less bleeding than NKPP, there are no differences in PEP, perforation, or total complication rates between the two approaches. We conclude that TPS, in the hands of expert endoscopists, is a safe procedure, which should be used more widely in patients with difficult biliary access.

In middle-aged and old obese patients, training intervention reduces leptin level: A meta-analysis

BACKGROUND

Leptin is one of the major adipokines in obesity that indicates the severity of fat accumulation. It is also an important etiological factor of consequent cardiometabolic and autoimmune disorders. Aging has been demonstrated to aggravate obesity and to induce leptin resistance and hyperleptinemia. Hyperleptinemia, on the other hand, may promote the development of age-related abnormalities. While major weight loss has been demonstrated to ameliorate hyperleptinemia, obese people show a poor tendency to achieve lasting success in this field. The question arises whether training intervention per se is able to reduce the level of this adipokine.

OBJECTIVES

We aimed to review the literature on the effects of training intervention on peripheral leptin level in obesity during aging, in order to evaluate the independent efficacy of this method. In the studies that were included in our analysis, changes of adiponectin levels (when present) were also evaluated.

DATA SOURCES

3481 records were identified through searching of PubMed, Embase and Cochrane Library Database. Altogether 19 articles were suitable for analyses.

STUDY ELIGIBILITY CRITERIA

Empirical research papers were eligible provided that they reported data of middle-aged or older (above 45 years of age) overweight or obese (body mass index above 25) individuals and included physical training intervention or at least fitness status of groups together with corresponding blood leptin values.

STATISTICAL METHODS

We used random effect models in each of the meta-analyses calculating with the DerSimonian and Laird weighting methods. I-squared indicator and Q test were performed to assess heterogeneity. To assess publication bias Egger's test was applied. In case of significant publication bias, the Duval and Tweedie's trim and fill algorithm was used.

RESULTS

Training intervention leads to a decrease in leptin level of middle-aged or older, overweight or obese male and female groups, even without major weight loss, indicated by unchanged serum adiponectin levels. Resistance training appears to be more efficient in reducing blood leptin level than aerobic training alone.

CONCLUSIONS

Physical training, especially resistance training successfully reduces hyperleptinemia even without diet or major weight loss.

Low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet improves symptoms in adults suffering from irritable bowel syndrome (IBS) compared to standard IBS diet: A meta-analysis of clinical studies

Background

Irritable bowel syndrome (IBS) and functional digestive tract disorders, e.g. functional bloating, carbohydrate maldigestion and intolerances, are very common disorders frequently causing significant symptoms that challenge health care systems. A low Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAP) diet is one of the possible therapeutic approaches for decreasing abdominal symptoms and improving quality of life.

Objectives

We aimed to meta-analyze data on the therapeutic effect of a low-FODMAP diet on symptoms of IBS and quality of life and compare its effectiveness to a regular, standard IBS diet with high FODMAP content, using a common scoring system, the IBS Symptom Severity Score (IBS-SSS).

Methods

A systematic literature search was conducted in PubMed, EMBASE and the Cochrane Library as well as in the references in a recent meta-analysis. Adult patients diagnosed with IBS according to the Rome II, Rome III, Rome IV or NICE criteria were included in the analysis.

Statistical methods

Mean differences with 95% confidence intervals were calculated from studies that contained means, standard deviation (SD) or mean differences and SD of differences and p-values. A random effect model was used because of the heterogeneity (Q test (χ2) and I² indicator). A p-value of less than 0.05 was chosen to indicate a significant difference.

Results

The literature search yielded 902 publications, but only 10 were eligible for our meta-analysis. Both regular and low-FODMAP diets proved to be effective in IBS, but post-diet IBS-SSS values were significantly lower (p = 0.002) in the low-FODMAP group. The low-FODMAP diet showed a correlation with the improvement of general symptoms (by IBS-SSS) in patients with IBS.

Conclusions

This meta-analysis provides high-grade evidence of an improved general symptom score among patients with irritable bowel syndrome who have maintained a low-FODMAP diet compared to those on a traditional IBS diet, therefore showing its superiority to regular IBS dietary therapy. These data suggest that a low-FODMAP diet with dietitian control can be a candidate for first-line therapeutic modality in IBS. Because of a lack of data, well-planned randomized controlled studies are needed to ascertain the correlation between improvement of separate key IBS symptoms and the effect of a low-FODMAP diet.

Is Heller myotomy better than balloon dilation? A meta-analysis

BACKGROUND AND AIM

Endoscopic balloon dilation (EBD) and laparoscopic Heller myotomy (LHM) are the most commonly performed treatment options for achalasia. Decision between these treatment options is difficult. The aim of this meta-analysis was to evaluate the efficacy of EBD compared to LHM.

METHODS

The electronic databases PubMed, Embase and Cochrane Controlled Trials Registry were systematically searched for the period between January 1, 1976 and December 31, 2015. Meta-analysis was performed using the PICOS (problem, intervention, comparison, outcome, study design) format. Efficacy and safety of EBD were compared to LHM. Forest plot analyses were used to illustrate the success rate, perforation rate and post-procedural gastroesophageal reflux.

RESULTS

Using the search strategy, eight studies met the selection criteria and were included in the meta-analysis. The total number of patients included was 749 (360 in the EBD group and 389 in the LHM group). The success rate was lower in the EBD group than in the LHM group (OR=0.486; CI: 0.304-0.779; p=0.003). The rate of perforation did not differ significantly between the EBD and LHM group (RR= 0.635, CI: 0.340-1.186, p=0.154). The incidence of post-procedural symptomatic gastroesophageal reflux did not differ between the two treatment groups (RR=0.663, CI: 0.328-1.343, p=0.254).

CONCLUSION

Our data suggest that the efficacy of LHM is superior to that of EBD, while there is no difference in safety between the two treatment groups.

In Obesity, HPA Axis Activity Does Not Increase with BMI, but Declines with Aging: A Meta-Analysis of Clinical Studies

Background

Obesity is one of the major public health challenges worldwide. It involves numerous endocrine disorders as etiological factors or as complications. Previous studies strongly suggested the involvement of the hypothalamic-pituitary-adrenal (HPA) axis activity in obesity, however, to date, no consistent trend in obesity-associated alterations of the HPA axis has been identified. Aging has been demonstrated to aggravate obesity and to induce abnormalities of the HPA axis. Thus, the question arises whether obesity is correlated with peripheral indicators of HPA function in adult populations.

Objectives

We aimed to meta-analyze literature data on peripheral cortisol levels as indicators of HPA activity in obesity during aging, in order to identify possible explanations for previous contradictory findings and to suggest new approaches for future clinical studies.

Data Sources

3,596 records were identified through searching of PubMed, Embase and Cochrane Library Database. Altogether 26 articles were suitable for analyses.

Study Eligibility Criteria

Empirical research papers were eligible provided that they reported data of healthy adult individuals, included body mass index (BMI) and measured at least one relevant peripheral cortisol parameter (i.e., either morning blood cortisol or 24-h urinary free cortisol).

Statistical Methods

We used random effect models in each of the meta-analyses calculating with the DerSimonian and Laird weighting methods. I-squared indicator and Q test were performed to assess heterogeneity. Meta-regression was applied to explore the effect of BMI and age on morning blood and urinary free cortisol levels. To assess publication bias Egger’s test was used.

Results

Obesity did not show any correlation with the studied peripheral cortisol values. On the other hand, peripheral cortisol levels declined with aging within the obese, but not in the non-obese groups.

Conclusions

Our analysis demonstrated that obesity or healthy aging does not lead to enhanced HPA axis activity, peripheral cortisol levels rather decline with aging.

Estrogen-dependent up-regulation of TRPA1 and TRPV1 receptor proteins in the rat endometrium

Transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) receptors expressed predominantly in sensory nerves are activated by inflammatory stimuli and mediate inflammation and pain. Although they have been shown in the human endometrium, their regulation and function are unknown. Therefore, we investigated their estrogen- and progesterone-dependent alterations in the rat endometrium in comparison with the estrogen-regulated inflammatory cytokine macrophage migration inhibitory factor (MIF). Four-week-old (sexually immature) and four-month-old (sexually mature) female rats were treated with the non-selective estrogen receptor (ER) agonist diethylstilboestrol (DES), progesterone and their combination, or ovariectomized. RT-PCR and immunohistochemistry were performed to determine mRNA and protein expression levels respectively. Channel function was investigated with ratiometric [Ca(2+)]i measurement in cultured primary rat endometrial cells. Both TRP receptors and MIF were detected in the endometrium at mRNA and protein levels, and their localizations were similar. Immunostaining was observed in the immature epithelium, while stromal, glandular and epithelial positivity were observed in adults. Functionally active TRP receptor proteins were shown in endometrial cells by activation-induced calcium influx. In adults, Trpa1 and Trpv1 mRNA levels were significantly up-regulated after DES treatment. TRPA1 increased after every treatment, but TRPV1 remained unchanged following the combined treatment and ovariectomy. In immature rats, DES treatment resulted in increased mRNA expression of both channels and elevated TRPV1 immunopositivity. MIF expression changed in parallel with TRPA1/TRPV1 in most cases. DES up-regulated Trpa1, Trpv1 and Mif mRNA levels in endometrial cell cultures, but 17β-oestradiol having ERα-selective potency increased only the expression of Trpv1. We provide the first evidence for TRPA1/TRPV1 expression and their estrogen-induced up-regulation in the rat endometrium in correlation with the MIF.

Age-dependence of alpha-MSH-induced anorexia

Long-term regulation of energy balance involves two major trends: first age-related obesity develops in the middle-aged, later it is followed by anorexia of aging (sarcopenia and/or cachexia). A dynamic balance between orexigenic and anorexigenic neuropeptides is essential for the regulation of energy homeostasis. Special imbalances of neuropeptide effects may be assumed corresponding to different age-periods. Anorexia induced by acute alpha-MSH (alpha-melanocyte stimulating hormone; endogenous melanocortin agonist) injections was analyzed in male Wistar rats aged 6-9 weeks (juvenile), 3-4 months (young adult), 6 or 12 months (two middle-aged groups), 18 months (aging) and 24-26 months (old). Alpha-MSH injected through a preimplanted intracerebroventricular (ICV) cannula (compared with saline injection) dose-dependently suppressed spontaneous food intake and also re-feeding following 24-h fasting, but the rate of suppression varied between age-groups. An ICV injection of 5 microg alpha-MSH attenuated the 2-h re-feeding by 21.9+/-3.2% in juvenile rats, strongly (68.7+/-2.5%) suppressed it in young adults, the suppression became progressively weaker in the two middle-aged groups (55.7+/-4.9%, vs. 26.4+/-4.9%, respectively), but it turned extreme in aging (94.7+/-4.2%) and old (74.3+/-4.5%) rats. Body composition also changed with age: unlike the tibialis anterior muscle, the epididymal and retroperitoneal fat pads increased until middle-age and remained large even in old animals, while the measured indicator of muscle mass decreased in the oldest group. The food intake suppressing and body weight decreasing effects of a 7-day-long ICV infusion of 1 microg/h alpha-MSH were weakest in the 12-month-old and most pronounced in the 24 month-old rats. In conclusion, responsiveness to the anorexic effect of alpha-MSH varies with age, with a nadir of the curve in the middle-aged, and a peak in the aging and old animals. This age-related nadir of melanocortin-responsiveness may promote obesity in middle-aged rats, while the tendency for anorexia and incipient sarcopenia of old (still obese) rats may result from age-related melanocortin-hypersensitivity rather than from adiposity.

Effects of repeated surgical stress on daily changes of body core temperature in mice

Daily body core temperature rhythm has been known to become blunted for several days following intra-abdominal implantation of biotelemetry transmitters in small rodents and about a week is required for re-establishment of stable body core temperature oscillation. In the present study carried out on mice it was found that a repetition of the same minor surgical intervention (laparotomy) several days apart could speed up the stabilization of body temperature oscillations. Melatonin supplied with the drinking water continuously was found to speed up the return of stable daily body temperature rhythm further on consecutive laparotomies, while daily injections of methylprednisolone resulted in some delay in the development of stable body core temperature oscillations. It is concluded that in C57BL/6 mice possessing low plasma levels of melatonin exhibit an adaptive response to repeated stresses influencing the dynamics of daily body temperature rhythm.

Energetics of fasting heterothermia in TRPV1-KO and wild type mice

To learn the possible role of TRPV1 in the changes of temperature regulation induced by short-term energy lack, TRPV1-KO and wild type mice were exposed to complete fasting for 2 or 3 days while their core temperature and locomotor activity were recorded using a biotelemetry method. In both types of mice, fasting led to progressive daytime hypothermia with night-time core temperature being maintained at normothermia (collectively called heterothermia). During fasting rises of locomotor activity were observed parallel to night-time normothermia with occasional increases of both parameters recorded every 2 to 3 hours (ultradian rhythms). The daytime fall of core temperature was significantly greater in wild type than in TRPV1-KO mice, in the former an advance of the temperature/activity rhythm having been observed in spite of the presence of a 12/12 hour light/darkness schedule. Re-feeding applied at the beginning of the light-period led to rapid reappearance of normothermia in both types of mice without a large increase in locomotor activity. It is concluded that the TRPV1-gene may have a role in the development of adaptive daytime hypothermia (and hence saving some energy) in mice during complete fasting but still allowing normothermia maintained at night, a strategy probably serving survival under natural conditions in small size rodents such as the mouse. The possible role of muscle thermogenesis either with or without gross bodily movement during fasting or on re-feeding, respectively, may be based on different mechanisms yet to be clarified.

Effects of perineural capsaicin treatment of the abdominal vagus on endotoxin fever and on a non-febrile thermoregulatory event

Following perineural capsaicin pretreatment of the main trunks of the abdominal vagus of rats, the first and the second phases of the polyphasic febrile response to intravenous lipopolysaccharide were unaltered, while the third phase of fever course (peak at 5 h) was attenuated. In rats desensitized by intraperitoneal (i.p.) capsaicin (i.e. abdominal non-systemic desensitization), mainly the first but not the later fever phases were reduced. The postprandial hyperthermia to intragastric injection of BaSO4 suspension was attenuated by either i.p. or perineural capsaicin treatment. It is concluded that, in contrast to the accepted model of postprandial hyperthermia, which is mediated by capsaicin-sensitive fibers of the abdominal vagus, in the early phase of polyphasic fever the vagal afferent nerves appear to play no role. The influence of i.p. capsaicin-desensitization on this initiating fever phase is independent of the vagus, and a capsaicin-induced alteration of endotoxin action in the liver, prior to vagal nerve endings, is more likely. The late febrile phase is probably influenced by efferent vagal fibers, which might be damaged more easily by perineural than i.p. capsaicin treatment.

Glycosylation defects and virulence phenotypes of Leishmania mexicana phosphomannomutase and dolicholphosphate-mannose synthase gene deletion mutants

Leishmania parasites synthesize an abundance of mannose (Man)-containing glycoconjugates thought to be essential for virulence to the mammalian host and for viability. These glycoconjugates include lipophosphoglycan (LPG), proteophosphoglycans (PPGs), glycosylphosphatidylinositol (GPI)-anchored proteins, glycoinositolphospholipids (GIPLs), and N-glycans. A prerequisite for their biosynthesis is an ample supply of the Man donors GDP-Man and dolicholphosphate-Man. We have cloned from Leishmania mexicana the gene encoding the enzyme phosphomannomutase (PMM) and the previously described dolicholphosphate-Man synthase gene (DPMS) that are involved in Man activation. Surprisingly, gene deletion experiments resulted in viable parasite lines lacking the respective open reading frames (DeltaPMM and DeltaDPMS), a result against expectation and in contrast to the lethal phenotype observed in gene deletion experiments with fungi. L. mexicana DeltaDPMS exhibits a selective defect in LPG, protein GPI anchor, and GIPL biosynthesis, but despite the absence of these structures, which have been implicated in parasite virulence and viability, the mutant remains infectious to macrophages and mice. By contrast, L. mexicana DeltaPMM are largely devoid of all known Man-containing glycoconjugates and are unable to establish an infection in mouse macrophages or the living animal. Our results define Man activation leading to GDP-Man as a virulence pathway in Leishmania.

The role of phosphomannose isomerase in Leishmania mexicana glycoconjugate synthesis and virulence

Phosphomannose isomerase (PMI) catalyzes the reversible interconversion of fructose 6-phosphate and mannose 6-phosphate, which is the first step in the biosynthesis of activated mannose donors required for the biosynthesis of various glycoconjugates. Leishmania species synthesize copious amounts of mannose-containing glycolipids and glycoproteins, which are involved in virulence of these parasitic protozoa. To investigate the role of PMI for parasite glycoconjugate synthesis, we have cloned the PMI gene (lmexpmi) from Leishmania mexicana, generated gene deletion mutants (Delta lmexpmi), and analyzed their phenotype. Delta lmexpmi mutants lack completely the high PMI activity found in wild type parasites, but are, in contrast to fungi, able to grow in media deficient for free mannose. The mutants are unable to synthesize phosphoglycan repeats [-6-Gal beta 1-4Man alpha 1-PO(4)-] and mannose-containing glycoinositolphospholipids, and the surface expression of the glycosylphosphatidylinositol-anchored dominant surface glycoprotein leishmanolysin is strongly decreased, unless the parasite growth medium is supplemented with mannose. The Delta lmexpmi mutant is attenuated in infections of macrophages in vitro and of mice, suggesting that PMI may be a target for anti-Leishmania drug development. L. mexicana Delta lmexpmi provides the first conditional mannose-controlled system for parasite glycoconjugate assembly with potential applications for the investigation of their biosynthesis, intracellular sorting, and function.