Protein intake and cancer: an umbrella review of systematic reviews for the evidence-based guideline of the German Nutrition Society

PURPOSE

It has been proposed that a higher habitual protein intake may increase cancer risk, possibly via upregulated insulin-like growth factor signalling. Since a systematic evaluation of human studies on protein intake and cancer risk based on a standardised assessment of systematic reviews (SRs) is lacking, we carried out an umbrella review of SRs on protein intake in relation to risks of different types of cancer.

METHODS

Following a pre-specified protocol (PROSPERO: CRD42018082395), we retrieved SRs on protein intake and cancer risk published before January 22th 2024, and assessed the methodological quality and outcome-specific certainty of the evidence using a modified version of AMSTAR 2 and NutriGrade, respectively. The overall certainty of evidence was rated according to predefined criteria.

RESULTS

Ten SRs were identified, of which eight included meta-analyses. Higher total protein intake was not associated with risks of breast, prostate, colorectal, ovarian, or pancreatic cancer incidence. The methodological quality of the included SRs ranged from critically low (kidney cancer), low (pancreatic, ovarian and prostate cancer) and moderate (breast and prostate cancer) to high (colorectal cancer). The outcome-specific certainty of the evidence underlying the reported findings on protein intake and cancer risk ranged from very low (pancreatic, ovarian and prostate cancer) to low (colorectal, ovarian, prostate, and breast cancer). Animal and plant protein intakes were not associated with cancer risks either at a low (breast and prostate cancer) or very low (pancreatic and prostate cancer) outcome-specific certainty of the evidence. Overall, the evidence for the lack of an association between protein intake and (i) colorectal cancer risk and (ii) breast cancer risk was rated as possible. By contrast, the evidence underlying the other reported results was rated as insufficient.

CONCLUSION

The present findings suggest that higher total protein intake may not be associated with the risk of colorectal and breast cancer, while conclusions on protein intake in relation to risks of other types of cancer are restricted due to insufficient evidence.

Dietary protein and blood pressure: an umbrella review of systematic reviews and evaluation of the evidence

INTRODUCTION

This umbrella review aimed to investigate the evidence of an effect of dietary intake of total protein, animal and plant protein on blood pressure (BP), and hypertension (PROSPERO: CRD42018082395).

METHODS

PubMed, Embase and Cochrane Database were systematically searched for systematic reviews (SRs) of prospective studies with or without meta-analysis published between 05/2007 and 10/2022. The methodological quality and outcome-specific certainty of evidence were assessed by the AMSTAR 2 and NutriGrade tools, followed by an assessment of the overall certainty of evidence. SRs investigating specific protein sources are described in this review, but not included in the assessment of the overall certainty of evidence.

RESULTS

Sixteen SRs were considered eligible for the umbrella review. Ten of the SRs investigated total protein intake, six animal protein, six plant protein and four animal vs. plant protein. The majority of the SRs reported no associations or effects of total, animal and plant protein on BP (all "possible" evidence), whereby the uncertainty regarding the effects on BP was particularly high for plant protein. Two SRs addressing milk-derived protein showed a reduction in BP; in contrast, SRs investigating soy protein found no effect on BP. The outcome-specific certainty of evidence of the SRs was mostly rated as low.

DISCUSSION/CONCLUSION

This umbrella review showed uncertainties whether there are any effects on BP from the intake of total protein, or animal or plant proteins, specifically. Based on data from two SRs with milk protein, it cannot be excluded that certain types of protein could favourably influence BP.

Protein intake and body weight, fat mass and waist circumference: an umbrella review of systematic reviews for the evidence-based guideline on protein intake of the German Nutrition Society

PURPOSE

This umbrella review aimed to assess whether dietary protein intake with regard to quantitative (higher vs. lower dietary protein intake) and qualitative considerations (total, plant-based or animal-based protein intake) affects body weight (BW), fat mass (FM) and waist circumference (WC).

METHODS

A systematic literature search was conducted in PubMed, Embase and Cochrane Database of Systematic Reviews for systematic reviews (SRs) with and without meta-analyses of prospective studies published between 04 October 2007 and 04 January 2022. Methodological quality and outcome-specific certainty of evidence of the retrieved SRs were assessed by using AMSTAR 2 and NutriGrade, respectively, in order to rate the overall certainty of evidence using predefined criteria.

RESULTS

Thirty-three SRs were included in this umbrella review; 29 were based on randomised controlled trials, a few included cohort studies. In studies without energy restriction, a high-protein diet did not modulate BW, FM and WC in adults in general (all "possible" evidence); for older adults, overall certainty of evidence was "insufficient" for all parameters. Under hypoenergetic diets, a high-protein diet mostly decreased BW and FM, but evidence was "insufficient" due to low methodological quality. Evidence regarding an influence of the protein type on BW, FM and WC was "insufficient".

CONCLUSION

"Possible" evidence exists that the amount of protein does not affect BW, FM and WC in adults under isoenergetic conditions. Its impact on the reduction in BW and FM under hypoenergetic conditions remains unclear; evidence for an influence of protein type on BW, FM and WC is "insufficient".

Protein intake and type 2 diabetes mellitus: an umbrella review of systematic reviews for the evidence-based guideline for protein intake of the German Nutrition Society

PURPOSE

Protein-rich foods show heterogeneous associations with the risk of type 2 diabetes (T2D) and it remains unclear whether habitual protein intake is related to T2D risk. We carried out an umbrella review of systematic reviews (SR) of randomised trials and/or cohort studies on protein intake in relation to risks of T2D.

METHODS

Following a pre-specified protocol (PROSPERO: CRD42018082395), we retrieved SRs on protein intake and T2D risk published between July 1st 2009 and May 22nd 2022, and assessed the methodological quality and outcome-specific certainty of the evidence using a modified version of AMSTAR 2 and NutriGrade, respectively. The overall certainty of evidence was rated according to predefined criteria.

RESULTS

Eight SRs were identified of which six contained meta-analyses. The majority of SRs on total protein intake had moderate or high methodological quality and moderate outcome-specific certainty of evidence according to NutriGrade, however, the latter was low for the majority of SRs on animal and plant protein. Six of the eight SRs reported risk increases with both total and animal protein. According to one SR, total protein intake in studies was ~ 21 energy percentage (%E) in the highest intake category and 15%E in the lowest intake category. Relative Risks comparing high versus low intake in most recent SRs ranged from 1.09 (two SRs, 95% CIs 1.02-1.15 and 1.06-1.13) to 1.11 (1.05-1.16) for total protein (between 8 and 12 cohort studies included) and from 1.13 (1.08-1.19) to 1.19 (two SRs, 1.11-1.28 and 1.11-1.28) (8-9 cohort studies) for animal protein. However, SRs on RCTs examining major glycaemic traits (HbA1c, fasting glucose, fasting insulin) do not support a clear biological link with T2D risk. For plant protein, some recent SRs pointed towards risk decreases and non-linear associations, however, the majority did not support an association with T2D risk.

CONCLUSION

Higher total protein intake was possibly associated with higher T2D risk, while there is insufficient evidence for a risk increase with higher intakes of animal protein and a risk decrease with plant protein intake. Given that most SRs on plant protein did not indicate an association, there is possibly a lack of an effect.

Addition of soluble fiber to standard purified diets is important for gut morphology in mice

Purified diets (PD) increase standardization and repeatability in rodent studies but lead to differences in the phenotype of animals compared to grain-based "chow" diets. PD contain less fiber and are often devoid of soluble fiber, which can impact gut health. Thus, the aim of the present study was to modify the PD AIN93G by addition of soluble fiber, to promote more natural gut development as seen with chow diets. One hundred twenty male C57BL/6J mice were fed over 12 weeks either a chow diet, AIN93G or one of three modified AIN93G with increased fiber content and different ratios of soluble fiber to cellulose. Gut health was assessed through histological and immunohistochemical parameters and gut barrier gene expression. Gut microbiota composition was analyzed and its activity characterized through short chain fatty acid (SCFA) quantification. Feeding AIN93G led to tissue atrophy, a less diverse microbiota and a lower production of SCFA compared to chow diet. The addition of soluble fiber mitigated these effects, leading to intermediate colon and caecum crypt lengths and microbiota composition compared to both control diets. In conclusion, the addition of soluble fibers in PDs seems essential for gut morphology as well as a diverse and functional gut microbiome.

Protein intake and bone health: an umbrella review of systematic reviews for the evidence-based guideline of the German Nutrition Society

This umbrella review aimed at assessing whether a protein intake exceeding the current recommendation for younger (0.8 g/kg body weight [BW]/day) and older (1.0 g/kg BW/day) adults affects bone mineral density and fracture risk. Moreover, the effect of animal or plant protein was evaluated. A systematic literature search was conducted in PubMed, Embase, and Cochrane Database of Systematic Reviews for systematic reviews (SRs) with or without meta-analysis of prospective studies published between 11/2008 and 08/2021. Methodological quality, outcome-specific certainty of evidence, and overall certainty of evidence of the retrieved SRs were assessed using established tools and predefined criteria. Eleven SRs of randomized controlled trials (RCTs) and/or cohort studies were included. In SRs of cohort studies and RCTs, protein intake/kg BW/day ranged between 0.21-0.95 g (low intake) and > 1.24 g (high intake), respectively, and between 0.67-1.1 g (control groups) and 1.01-1.69 g (intervention groups), respectively. The vast majority of outcome-specific certainty of evidence was rated "low" or "very low." The overall certainty of evidence for an association (cohort studies) or effect (RCTs) of total, animal or plant protein intake on each of the investigated outcomes was rated "insufficient," with the exception of possible evidence for a reduced hip fracture risk by high vs. low protein intake. Since protein intakes in low/control and high/intervention groups were very heterogeneous and with low certainty of evidence, it remains unclear whether a dose above the current recommendation or type of protein intake (animal or plant protein) affects bone health overall. However, there is possible evidence for reduced hip fracture risk with high versus low protein intake.

Assessment of Energy and Nutrient Intake and the Intestinal Microbiome (ErNst study): Protocol and Methods of a Cross-sectional Human Observational Study (Preprint)

BACKGROUND

On the national level, nutritional monitoring requires the assessment of reliable representative dietary intake data. To achieve this, standardized tools need to be developed, validated, and kept up-to-date with recent developments in food products and the nutritional behavior of the population. Recently, the human intestinal microbiome has been identified as an essential mediator between nutrition and host health. Despite growing interest in this connection, only a few associations between the microbiome, nutrition, and health have been clearly established. Available studies paint an inconsistent picture, partly due to a lack of standardization.

OBJECTIVE

First, we aim to verify if food consumption, as well as energy and nutrient intake of the German population, can be recorded validly by means of the dietary recall software GloboDiet, which will be applied in the German National Nutrition Monitoring. Second, we aim to obtain high-quality data using standard methods on the microbiome, combined with dietary intake data and additional fecal sample material, and to also assess the functional activity of the microbiome by measuring microbial metabolites.

METHODS

Healthy female and male participants aged between 18 and 79 years were recruited. Anthropometric measurements included body height and weight, BMI, and bioelectrical impedance analysis. For validation of the GloboDiet software, current food consumption was assessed with a 24-hour recall. Nitrogen and potassium concentrations were measured from 24-hour urine collections to enable comparison with the intake of protein and potassium estimated by the GloboDiet software. Physical activity was measured over at least 24 hours using a wearable accelerometer to validate the estimated energy intake. Stool samples were collected in duplicate for a single time point and used for DNA isolation and subsequent amplification and sequencing of the 16S rRNA gene to determine microbiome composition. For the identification of associations between nutrition and the microbiome, the habitual diet was determined using a food frequency questionnaire covering 30 days.

RESULTS

In total, 117 participants met the inclusion criteria. The study population was equally distributed between the sexes and 3 age groups (18-39, 40-59, and 60-79 years). Stool samples accompanying habitual diet data (30-day food frequency questionnaire) are available for 106 participants. Current diet data and 24-hour urine samples for the validation of GloboDiet are available for 109 participants, of which 82 cases also include physical activity data.

CONCLUSIONS

We completed the recruitment and sample collection of the ErNst study with a high degree of standardization. Samples and data will be used to validate the GloboDiet software for the German National Nutrition Monitoring and to compare microbiome composition and nutritional patterns.

TRIAL REGISTRATION

German Register of Clinical Studies DRKS00015216; https://drks.de/search/de/trial/DRKS00015216.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/42529.

Dietary protein intake and health-related outcomes: a methodological protocol for the evidence evaluation and the outline of an evidence to decision framework underlying the evidence-based guideline of the German Nutrition Society

PURPOSE

The present work aimed to delineate (i) a revised protocol according to recent methodological developments in evidence generation, to (ii) describe its interpretation, the assessment of the overall certainty of evidence and to (iii) outline an Evidence to Decision framework for deriving an evidence-based guideline on quantitative and qualitative aspects of dietary protein intake.

METHODS

A methodological protocol to systematically investigate the association between dietary protein intake and several health outcomes and for deriving dietary protein intake recommendations for the primary prevention of various non-communicable diseases in the general adult population was developed.

RESULTS

The developed methodological protocol relies on umbrella reviews including systematic reviews with or without meta-analyses. Systematic literature searches in three databases will be performed for each health-related outcome. The methodological quality of all selected systematic reviews will be evaluated using a modified version of AMSTAR 2, and the outcome-specific certainty of evidence for systematic reviews with or without meta-analysis will be assessed with NutriGrade. The general outline of the Evidence to Decision framework foresees that recommendations in the derived guideline will be given based on the overall certainty of evidence as well as on additional criteria such as sustainability.

CONCLUSION

The methodological protocol permits a systematic evaluation of published systematic reviews on dietary protein intake and its association with selected health-related outcomes. An Evidence to Decision framework will be the basis for the overall conclusions and the resulting recommendations for dietary protein intake.

Preterm neonate delivered to COVID-19 positive mother on ECMO support

Despite ongoing research and recent discoveries, there remains a paucity of data regarding COVID-19 and its implications for pregnant women, particularly its effects on the developing fetus. To date, there are a limited number of articles available regarding the utility of Extra Corporeal Membrane Oxygenation (ECMO) for cardio-respiratory support of pregnant women during the perinatal period. Additionally, there are only a few case reports detailing the delivery management of a baby born to a mother on ECMO support. Here, we report a case of a premature, low birth weight neonate delivered by a 32-year-old woman while on ECMO due to severe acute respiratory distress syndrome resulting from COVID-19 infection.

Hippocampal Sclerosis Detection with NeuroQuant Compared with Neuroradiologists

BACKGROUND AND PURPOSE

NeuroQuant is an FDA-approved software that performs automated MR imaging quantitative volumetric analysis. This study aimed to compare the accuracy of NeuroQuant analysis with visual MR imaging analysis by neuroradiologists with expertise in epilepsy in identifying hippocampal sclerosis.

MATERIALS AND METHODS

We reviewed 144 adult patients who underwent presurgical evaluation for temporal lobe epilepsy. The reference standard for hippocampal sclerosis was defined by having hippocampal sclerosis on pathology (n = 61) or not having hippocampal sclerosis on pathology (n = 83). Sensitivities, specificities, positive predictive values, and negative predictive values were compared between NeuroQuant analysis and visual MR imaging analysis by using a McNemar paired test of proportions and the Bayes theorem.

RESULTS

NeuroQuant analysis had a similar specificity to neuroradiologist visual MR imaging analysis (90.4% versus 91.6%; P = .99) but a lower sensitivity (69.0% versus 93.0%, P < .001). The positive predictive value of NeuroQuant analysis was comparable with visual MR imaging analysis (84.0% versus 89.1%), whereas the negative predictive value was not comparable (79.8% versus 95.0%).

CONCLUSIONS

Visual MR imaging analysis by a neuroradiologist with expertise in epilepsy had a higher sensitivity than did NeuroQuant analysis, likely due to the inability of NeuroQuant to evaluate changes in hippocampal T2 signal or architecture. Given that there was no significant difference in specificity between NeuroQuant analysis and visual MR imaging analysis, NeuroQuant can be a valuable tool when the results are positive, particularly in centers that lack neuroradiologists with expertise in epilepsy, to help identify and refer candidates for temporal lobe epilepsy resection. In contrast, a negative test could justify a case referral for further evaluation to ensure that false-negatives are detected.

Bioavailability and Safety of Nutrients from the Microalgae Chlorella vulgaris, Nannochloropsis oceanica and Phaeodactylum tricornutum in C57BL/6 Mice

Microalgae are rich in macronutrients and therefore, they have been proposed as a potential future food source preserving natural resources. Here, we studied safety and bioavailability of algae nutrients in mice. Three microalgae species, Chlorella vulgaris, Nannochloropsis oceanica and Phaeodactylum tricornutum, were studied after ball mill disruption at different doses (5%, 15% and 25% dry weight) for 14 days. In response to all three algae diets, we observed a weight gain similar or superior to that in response to the control diet. No substantial differences in organ weights nor gut length occurred. Protein bioavailability from the algae diets did not differ from the control diet ranging from 58% to 77% apparent biological value. Fat absorption was lower for microalgae compared to soy oil in control diets, albeit still substantial. High liver eicosapentaenoic acid levels were measured following feeding with N. oceanica, the algae richest in omega-3 fatty acids. Neither histological nor serum analyses revealed any heart, kidney or liver toxicity induced by any of the algae diets. Algae-rich diets were thus well accepted, well tolerated and suitable for the maintenance of body weight and normal organ function. No toxicological effects were observed.

Antineoplastic agents exacerbating Charcot Marie Tooth disease: red flags to avoid permanent disability

BACKGROUND

Charcot Marie Tooth (CMT) disease is the most common form of hereditary neuropathy. Due to the high prevalence of mild and undiagnosed forms, patients with CMT disease may be exposed to severe neurotoxicity following the administration of neurotoxic chemotherapies. The aim of this report is to alert oncologists to the potential to precipitate severe irreversible peripheral neuropathies when administering neurotoxic compounds to undiagnosed CMT patients.

MATERIAL AND METHODS

A retrospective research in the OncoNeuroTox database was performed (2010-2016), searching for patients with the diagnosis of chemotherapy-induced peripheral neuropathy (CIPN) and CMT disease. A comprehensive literature review for previously published cases was performed using the Pubmed and Cochrane databases (1972-2017).

RESULTS

Among 428 patients with CIPN, we identified eight patients with concomitant CMT disease. Seven patients out of the eight had no previous diagnosis of CMT disease, although accurate familial history disclosed mild signs of peripheral neuropathy in five cases. Patients themselves had minor stigmata of long-standing peripheral damage. Patients received chemotherapy regimens based on vinca alkaloids, taxanes or a combination of vinca alkaloids and platinum compounds. In two cases, cumulative doses were below or equal to the expected neurotoxic threshold. Following chemotherapy administration, patients developed severe length-dependent sensory-motor deficits. Despite early drug discontinuation, most patients remained severely disabled.

CONCLUSION

A brief checklist to disclose long-standing signs of peripheral neuropathy could be helpful to detect patients with undiagnosed hereditary neuropathies who could be at risk of developing severe irreversible neurotoxicity following the administration of neurotoxic agents.

Intestinal Barrier Function and the Gut Microbiome Are Differentially Affected in Mice Fed a Western-Style Diet or Drinking Water Supplemented with Fructose

Background: The consumption of a Western-style diet (WSD) and high fructose intake are risk factors for metabolic diseases. The underlying mechanisms are largely unclear.Objective: To unravel the mechanisms by which a WSD and fructose promote metabolic disease, we investigated their effects on the gut microbiome and barrier function.Methods: Adult female C57BL/6J mice were fed a sugar- and fat-rich WSD or control diet (CD) for 12 wk and given access to tap water or fructose-supplemented water. The microbiota was analyzed with the use of 16S rRNA gene sequencing. Barrier function was studied with the use of permeability tests, and endotoxin, mucus thickness, and gene expressions were measured.Results: The WSD increased body weight gain but not endotoxin translocation compared with the CD. In contrast, high fructose intake increased endotoxin translocation 2.6- and 3.8-fold in the groups fed the CD + fructose and WSD + fructose, respectively, compared with the CD group. The WSD + fructose treatment also induced a loss of mucus thickness in the colon (-46%) and reduced defensin expression in the ileum and colon. The lactulose:mannitol ratio in the WSD + fructose mice was 1.8-fold higher than in the CD mice. Microbiota analysis revealed that fructose, but not the WSD, increased the Firmicutes:Bacteroidetes ratio by 88% for CD + fructose and 63% for WSD + fructose compared with the CD group. Bifidobacterium abundance was greater in the WSD mice than in the CD mice (63-fold) and in the WSD + fructose mice than in the CD + fructose mice (330-fold).Conclusions: The consumption of a WSD or high fructose intake differentially affects gut permeability and the microbiome. Whether these differences are related to the distinct clinical outcomes, whereby the WSD primarily promotes weight gain and high fructose intake causes barrier dysfunction, needs to be investigated in future studies.

Gut permeability is related to body weight, fatty liver disease, and insulin resistance in obese individuals undergoing weight reduction

BACKGROUND

Obesity and associated metabolic disorders are related to impairments of the intestinal barrier.

OBJECTIVE

We examined lactulose:mannitol (Lac:Man) permeability in obese individuals with and without liver steatosis undergoing a weight-reduction program to test whether an effective weight-loss program improves gut barrier function and whether obese patients with or without liver steatosis differ in this function.

DESIGN

Twenty-seven adult, nondiabetic individuals [mean ± SD body mass index (BMI; in kg/m²): 43.7 ± 5.2; 78% with moderate or severe liver steatosis] were included in the follow-up intervention study (n = 13 by month 12). All patients reduced their weight to a mean ± SD BMI of 36.4 ± 5.1 within 12 mo. We assessed barrier functions by the oral Lac:Man and the fecal zonulin tests. Insulin resistance was assessed by the homeostatic model assessment index (HOMA), and liver steatosis by sonography and the fatty liver index (FLI).

RESULTS

The Lac:Man ratio and circulating interleukin (IL) 6 concentration decreased during intervention from 0.080 (95% CI: 0.073, 0.093) to 0.027 (95% CI: 0.024, 0.034; P < 0.001) and from 4.2 ± 1.4 to 2.8 ± 1.6 pg/mL (P < 0.01), respectively. At study start, the Lac:Man ratio was higher in patients with moderate or severe steatosis than in those without any steatosis (P < 0.001). The Lac:Man ratio tended to correlate with HOMA (ρ = 0.55, P = 0.052), which correlated with FLI (ρ = 0.75, P < 0.01). A multiple-regression analysis led to a final model explaining FLI best through BMI, waist circumference, and the Lac:Man ratio.

CONCLUSIONS

Intestinal permeability is increased in obese patients with steatosis compared with obese patients without. The increased permeability fell to within the previously reported normal range after weight reduction. The data suggest that a leaky gut barrier is linked with liver steatosis and could be a new target for future steatosis therapies. This trial was registered at clinicaltrials.gov as NCT01344525.

Intestinal Microbiota and Microbial Metabolites Are Changed in a Pig Model Fed a High-Fat/Low-Fiber or a Low-Fat/High-Fiber Diet

The intestinal microbiota and its metabolites appear to be an important factor for gastrointestinal function and health. However, research is still needed to further elaborate potential relationships between nutrition, gut microbiota and host’s health by means of a suitable animal model. The present study examined the effect of two different diets on microbial composition and activity by using the pig as a model for humans. Eight pigs were equally allotted to two treatments, either fed a low-fat/high-fiber (LF), or a high-fat/low-fiber (HF) diet for 7 weeks. Feces were sampled at day 7 of every experimental week. Diet effects on fecal microbiota were assessed using quantitative real-time PCR, DNA fingerprinting and metaproteomics. Furthermore, fecal short-chain fatty acid (SCFA) profiles and ammonia concentrations were determined. Gene copy numbers of lactobacilli, bifidobacteria (P<0.001) and Faecalibacterium prausnitzii (P<0.05) were higher in the LF pigs, while Enterobacteriaceae were more abundant in the HF pigs (P<0.001). Higher numbers of proteins affiliated to Enterobacteriaceae were also present in the HF samples. Proteins for polysaccharide breakdown did almost exclusively originate from Prevotellaceae. Total and individual fecal SCFA concentrations were higher for pigs of the LF treatment (P<0.05), whereas fecal ammonia concentrations did not differ between treatments (P>0.05). Results provide evidence that beginning from the start of the experiment, the LF diet stimulated beneficial bacteria and SCFA production, especially butyrate (P<0.05), while the HF diet fostered those bacterial groups which have been associated with a negative impact on health conditions. These findings correspond to results in humans and might strengthen the hypothesis that the response of the porcine gut microbiota to a specific dietary modulation is in support of using the pig as suitable animal model for humans to assess diet-gut-microbiota interactions.

Data are available via ProteomeXchange with identifier PXD003447.

Characterization of the Gut Microbial Community of Obese Patients Following a Weight-Loss Intervention Using Whole Metagenome Shotgun Sequencing

Background/Objectives

Cross-sectional studies suggested that obesity is promoted by the gut microbiota. However, longitudinal data on taxonomic and functional changes in the gut microbiota of obese patients are scarce. The aim of this work is to study microbiota changes in the course of weight loss therapy and the following year in obese individuals with or without co-morbidities, and to asses a possible predictive value of the gut microbiota with regard to weight loss maintenance.

Subjects/Methods

Sixteen adult patients, who followed a 52-week weight-loss program comprising low calorie diet, exercise and behavioral therapy, were selected according to their weight-loss course. Over two years, anthropometric and metabolic parameters were assessed and microbiota from stool samples was functionally and taxonomically analyzed using DNA shotgun sequencing.

Results

Overall the microbiota responded to the dietetic and lifestyle intervention but tended to return to the initial situation both at the taxonomical and functional level at the end of the intervention after one year, except for an increase in Akkermansia abundance which remained stable over two years (12.7x10³ counts, 95%CI: 322–25100 at month 0; 141x10³ counts, 95%CI: 49-233x10³ at month 24; p = 0.005). The Firmicutes/Bacteroidetes ratio was higher in obese subjects with metabolic syndrome (0.64, 95%CI: 0.34–0.95) than in the “healthy obese” (0.27, 95%CI: 0.08–0.45, p = 0.04). Participants, who succeeded in losing their weight consistently over the two years, had at baseline a microbiota enriched in Alistipes, Pseudoflavonifractor and enzymes of the oxidative phosphorylation pathway compared to patients who were less successful in weight reduction.

Conclusions

Successful weight reduction in the obese is accompanied with increased Akkermansia numbers in feces. Metabolic co-morbidities are associated with a higher Firmicutes/Bacteroidetes ratio. Most interestingly, microbiota differences might allow discrimination between successful and unsuccessful weight loss prior to intervention.

Profound and persistent decrease of circulating dendritic cells is associated with ICU-acquired infection in patients with septic shock

PURPOSE

Septic shock induces a decrease in dendritic cells (DCs) that may contribute to sepsis-induced immunosuppression. We analyzed the time course of circulating DCs in patients with septic shock and its relation to susceptibility to intensive care unit (ICU)-acquired infections.

METHODS

We enrolled adult patients with septic shock (n = 43), non-septic shock (n = 29), and with sepsis without organ dysfunction (n = 16). Healthy controls (n = 16) served as reference. Blood samples were drawn on the day of shock (day 1), then after 3 and 7 days. Myeloid (mDC) and plasmacytoid (pDC) DCs were counted by flow cytometry. Cell surface HLA-DR expression was analyzed in both DC subsets.

RESULTS

At day 1, median mDC and pDC counts were dramatically lower in septic shock patients as compared to healthy controls (respectively, 835 mDCs and 178 pDCs/ml vs. 19,342 mDCs and 6,169 pDCs/ml; P < 0.0001) but also to non-septic shock and sepsis patients (P < 0.0001). HLA-DR expression was decreased in both mDCs and pDCS within the septic shock group as compared to healthy controls. DC depletion was sustained for at least 7 days in septic shock patients. Among them, 10/43 developed ICU-acquired infections after a median of 9 [7.5-11] days. At day 7, mDC counts increased in patients devoid of secondary infections, whereas they remained low in those who subsequently developed ICU-acquired infections.

CONCLUSION

Septic shock is associated with profound and sustained depletion of circulating DCs. The persistence of low mDC counts is associated with the development of ICU-acquired infections, suggesting that DC depletion is a functional feature of sepsis-induced immunosuppression.

How effective is endovascular intracranial revascularization in stroke prevention? Results from Borgess Medical Center Intracranial Revascularization Registry

BACKGROUND AND PURPOSE

The WASID study established the risk of subsequent ischemic stroke at 1 year in subjects with symptomatic intracranial atherosclerotic stenosis (70%-99%) at 18%. The efficacy of different methods of endovascular revascularization in stroke prevention still has not been established. We compared the stroke rate in our registry at 1 year following intervention with the WASID results to identify which method, if any, provides the most benefit in stroke prevention. This result from the BMC-IRR follows a previously published article comparing stent placement and angioplasty outcomes.

MATERIALS AND METHODS

We maintained a nonrandomized single-center single-operator registry of consecutive symptomatic patients who underwent endovascular intracranial revascularization. Data were collected prospectively and retrospectively and analyzed retrospectively. Patients were treated with angioplasty, BMS, or self-expanding WS. To make our data comparable with that in the WASID study, we selected patients with a single lesion of 50%-99% stenosis undergoing a single intervention. Data was collected on patients until symptom recurrence, repeat intervention, or 1 year postintervention, whichever occurred first.

RESULTS

We found that 115 patients fit the inclusion criteria, with 38 angioplasty, 28 BMS, and 49 WS cases. For patients with 70%-99% stenosis, the overall probability of stroke at 1 year postintervention was 19.3%. The overall stroke probability per device, independent of clinical presentation, was 12.5% for angioplasty, 20.2% for BMS, and 24.1% for WS.

CONCLUSIONS

Compared with the WASID data, angioplasty appears to have a lower stroke rate after 1 year than medical therapy alone. However, neither stent-placement arm compared favorably with the WASID results.

Predictors of unfavorable outcome in intracranial angioplasty and stenting in a single-center comparison: results from the Borgess Medical Center-Intracranial Revascularization Registry

BACKGROUND AND PURPOSE

Intracranial angioplasty and stent placement are used to treat intracranial atherosclerotic disease. The 2 interventions have not been directly compared.

MATERIALS AND METHODS

This was a single-center, single-operator registry of consecutive, symptomatic subjects receiving treatment (angioplasty, BMS, or WS, chosen based on safety as judged by the operator). After November 2005, angioplasty alone was abandoned following the introduction of the WS. The primary end point was stroke rate per intervention at 30 days. The secondary end point was stroke rate per patient beyond 30 days. Success, dissection, restenosis, and occlusion rates were tracked.

RESULTS

From April 2002 to January 2009, 140 subjects with 159 lesions (50%-100% stenosis) underwent 209 interventions: 89 angioplasty, 47 BMS, and 73 WS cases. Overall stroke rate at 30 days was 12.9%. The angioplasty arm had the lowest stroke rate (4.5%), whereas the WS arm had the highest (24.7%; P = .0002), leaving the BMS with 10.7%. Stroke rate beyond 30 days was 9%. The success rate was 58.4% for angioplasty, 81.3% for BMS, and 94.4% for WS, whereas the restenosis rates were 28.2%, 5.8%, and 13.3%, respectively. Dissection increased the risk of stroke in the first 30 days (P = .0439) and restenosis (P = .0051). Perforator vessels were more likely than nonperforators to have stroke within 30 days (P = .008). Eccentric lesions were more likely to have stroke than concentric lesions (P = .0726).

CONCLUSIONS

In this comparison, angioplasty had a significantly lower stroke rate than WS. Certain lesion locations, morphologic characteristics, and the presence of dissection after treatment were other predictors of unfavorable outcome.

Isoprene emission protects photosynthesis in sunfleck exposed Grey poplar

In the present study, we combined transient temperature and light stress (sunfleck) and comparably analyzed photosynthetic gas exchange in Grey poplar which has been genetically modified in isoprene emission capacity. Overall, we demonstrate that for poplar leaves the ability to emit isoprene is crucial to maintain photosynthesis when exposed to sunflecks. Net CO2 assimilation and electron transport rates were strongly impaired in sunfleck-treated non-isoprene emitting poplars. Similar impairment was not detected when the leaves were exposed to high light (lightflecks) only. Within 10 h non-isoprene emitting poplars recovered from sunfleck-related impairment as indicated by chlorophyll fluorescence and microarray analysis. Unstressed leaves of non-isoprene emitting poplars had higher ascorbate contents, but also higher contents of malondialdehyde than wild-type. Microarray analyses revealed lipid and chlorophyll degradation processes in the non-isoprene emitting poplars. Thus, there is evidence for an adjustment of the antioxidative system in the non-isoprene emitting poplars even under normal growth conditions.

Poplar volatiles - biosynthesis, regulation and (eco)physiology of isoprene and stress-induced isoprenoids

Plants interact with their environment through a wide variety of biogenic volatile organic compounds (BVOCs), with isoprenoids ( identical with terpenes), i.e. isoprene, mono- and sesquiterpenes, playing an important role. Isoprene, a hemiterpene, is the simplest isoprenoid compound mainly emitted by tree species like poplars, oaks and willows. Woody plants alone comprise 75% of the global isoprene emitted to the atmosphere. Due to its significant influence on atmospheric chemistry, research has been focused on this C5 compound, with poplar being the most prominent model system. Recent studies indicate that isoprene can enhance thermotolerance or quench oxidative stress, while also interfering with the attraction of herbivores and parasitoids to plants. In this paper, we report on biosynthesis, regulation and function of isoprene and other stress-induced volatile isoprenoids in poplar, and discuss the future scientific challenges in this genus with respect to the importance of plant volatiles in high-density poplar biomass plantations.

Nonmicrobial aerobic methane emission from poplar shoot cultures under low-light conditions

The aerobic formation of methane in plants has been reported previously, but has been questioned by a number of researchers. Recently, isotopic evidence demonstrated that ultraviolet irradiation and heating lead to photochemical or thermal aerobic methane formation mainly from plant pectin in the absence of microbial methane production. However, the origin of aerobic methane formation from plant material observed under low temperature and low-light/dark conditions is still unclear. Here we show that Grey poplar (Populus × canescens, syn. Populus tremula × Populus alba) plants derived from cell cultures under sterile conditions released 13C-labeled methane under low-light conditions after feeding the plants with 13CO2. Molecular biological analysis proved the absence of any microbial contamination with known methanogenic microorganisms and ruled out the possibility that methane emission from our poplar shoot cultures under aerobic low-light/dark and ambient temperature conditions could be of microbial origin. The CH4 release rates in our experiment were in the range of 0.16-0.7 ng g-1 DW h-1, adding evidence to the growing opinion that the quantitative role of aerobic methane emissions from plants in the global methane budget, at least from cold temperate or boreal regions, is only of minor importance.

Regulation of isoprene synthase promoter by environmental and internal factors

Isoprene synthase (ISPS) catalyzes the formation of isoprene, an important volatile terpenoid with strong effects on global atmospheric chemistry and protective physiological functions in plant leaves. Many terpene synthase genes including isoprene synthase, a member of the TPS-b cluster of this numerous gene family, were already functionally analysed but much less is known about regulation of their promoters. To study regulation of the PcISPS gene in detail we developed transgenic Grey poplar (Populus x canescens) and Arabidopsis thaliana plants in which the PcISPS promoter is fused to enhanced green fluorescent protein (E-GFP) and beta-glucuronidase (GUS) reporter genes. We analysed these reporters during plant development, for organ specificity and in plants subjected to different light and temperature regimes. We observed low promoter activity in non-isoprene emitting tissue like roots where ISPS gene is transcribed but no active enzyme is detectable. In leaves we demonstrate that light and temperature directly modulate ISPS promoter activity. Moreover, with confocal laser scanning microscopy we show a cell specific gradient of ISPS promoter activity within the leaf parenchyma depending on light direction. Our results indicate that ISPS promoter activity, which correlates with basal isoprene emission capacity, is not uniformly distributed within leaf tissue and that it can adapt rapidly towards internal as well as external environmental stimuli.

Natural history of multiple sclerosis in a population-based cohort

BACKGROUND AND PURPOSE

We sought to identify predictive clinical factors of disability during initial course in multiple sclerosis (MS) patients.

METHODS

A total of 2871 MS patients from the LORSEP (Lorraine Multiple Sclerosis) population-based cohort were analyzed. The relationships between baseline demographic, clinical predictors and time to assignment of Expanded Disability Status Scale (EDSS) scores of 3, 4 and 6 were assessed using a Cox regression model.

RESULTS

Multivariate analysis showed that, for relapsing-remitting patients, a shorter time to assignment of an EDSS score of 4 was associated with an older age of onset of MS and incomplete recovery from the first relapse. Median times were not influenced by gender or the time between the first two relapses. The results also demonstrated that MS progression is independent of the initial clinical data once an EDSS score of 4 is reached rather than a score of 3 because the time from EDSS 3 to assignment of EDSS 4 were correlated with predicting variables. The data were very different for the time between assignment of scores of 4 and 6 because the median times were not influenced by any of the predicting variables.

Transgenic, non-isoprene emitting poplars don't like it hot

The physiological role of isoprene emission in plants is a matter of much debate. One of the most widely propagated hypotheses suggests a function of isoprene in the protection of leaf physiological processes against thermal and oxidative stress. To test this hypothesis, we developed transgenic Grey poplar (Populusxcanescens) plants in which gene expression of isoprene synthase (ISPS) was either silenced by RNA interference (RNAi) or upregulated by over-expression of the ISPS gene. Despite increased ISPS mRNA levels, we did not observe consistent increases in isoprene emission in the over-expressing lines, indicating post-transcriptional control of ISPS by co-suppression. In the RNAi lines, levels of isoprene emission were effectively suppressed to virtually zero. Transgenic plants were subjected to temperature stress with three transient heat phases of 38-40 degrees C, each followed by phases of recovery at 30 degrees C. Parallel measurements of gas exchange, chlorophyll fluorescence and isoprene emission provided new insights into the physiological link between isoprene and enhanced temperature tolerance. Transgenic non-isoprene-emitting poplars showed reduced rates of net assimilation and photosynthetic electron transport during heat stress, but not in the absence of stress. The decrease in the efficiency of photochemistry was inversely correlated with the increase in heat dissipation of absorbed light energy, measured as NPQ (non-photochemical quenching). Isoprene-repressed poplars also displayed an increased formation of the xanthophyll cycle pigment zeaxanthin in the absence of stress, which can cause increased NPQ or may indicate an increased requirement for antioxidants. In conclusion, using a molecular genetic approach, we show that down-regulation of isoprene emission affects thermotolerance of photosynthesis and induces increased energy dissipation by NPQ pathways.

Increasing incidence of multiple sclerosis among women in Lorraine, Eastern France

This study aims to describe the prevalence and incidence rates of multiple sclerosis (MS) in Lorraine, France, and its secular trend from 1990 to 2002. Cases were sourced from the regional network of MS healthcare workers in the Lorraine region and include all cases with definite or probable MS according to Poser's criteria. We identified 2718 patients with MS on 31 December 2004. The prevalence rate was 120/100,000 (95% confidence interval [CI]: 119-121). Between 1990 and 2002, the average age- and sex-adjusted annual incidence rate was 5.5/100,000 (95% CI: 4.4-6.6). During this same period, there was a significant increase in overall incidence in women but not in men. The mean age at MS onset, disability score five years after onset, number of relapses during the first five years, and proportion of first attack with sequelae or polysymptomatic symptoms were not significantly different between each annual cohort during the study period. The prevalence and incidence rates of MS we found in our study were higher than in previous studies in France. The increase in incidence of MS between 1990 and 2002, mostly in women, was not related to better ascertainment of patients with mild disability.

Validity of a French version of the fatigue impact scale in multiple sclerosis

Purpose Fatigue is a frequent and common symptom of multiple sclerosis (MS) that can interfere with patients' everyday activities. There is no objective scale for assessing fatigue in French MS patients. The objective of this study was to adapt an English language scale for use with French patients.

Methods The Fatigue Impact Scale was translated and culturally adapted into French by a committee of medical and linguistic specialists. The psychometric properties of this new instrument, called EMIF-SEP were assessed.

Results EMIF-SEP is composed of 40 items. Four dimensions of this scale (cognitive, physical, social role and psychological) were identified by factor analysis. Each dimension had a high internal consistency (Cronbach's alpha >0.80). The test-retest reproducibility was very satisfactory; intra-class correlation coefficients were all above 0.70.

Conclusion EMIF-SEP is the first scale for assessing MS-related fatigue which has been adapted to French-speaking patients. It is useful for clinical practice and MS-related research. Multiple Sclerosis 2007; 13: 1026—1032. http://msj.sagepub.com

Multiple sclerosis with a progressive course from onset in Lorraine-Eastern France

To investigate the patient characteristics, disease progression, and associated risk factors in patients with multiple sclerosis (MS) with a progressive onset, we conducted a longitudinal population-based study of 359 patients (252 with primary progressive MS (PPMS) and 107 with progressive relapsing MS (PRMS)) in Lorraine, France. As outcome measures, we assessed the time from MS onset to reaching disability status scale (DSS) scores of 4, 6 and 7 and the time from assignment of DSS score of 6 to assignment of DSS score of 7. We studied the influence on these outcomes of sex, age of onset and symptoms of onset. We also studied the influence of the time from MS onset to assignment of DSS 6 on the time from MS onset to assignment of DSS 7. There were no significant differences in the demographic data (gender and age at onset of MS) and clinical data (median time to DSS scores of 4, 6 and 7) between the patients with PPMS and PRMS suggesting such a distinction may be unnecessary. The male/female ratio in all 359 patients with MS with a progressive onset was 1/1.36. The median age at onset was 42.7 years (25% Q1 = 34.7; 75% Q3 = 50.0), was lower for male (40.5 years) than for female patients (44.2 years; p = 0.002). The median time to DSS scores of 4, 6 and 7 were (in years) 3.0 (95% CI = 2.8 to 3.7), 9.9 (95% CI = 9.0 to 10.6), and 17.0 (95% CI = 14.9 to 19.0). A cane was required in 25% of patients 5 years after onset and in 75% 15 years after onset. We did not find any significant unfluence of sex, age at onset, or symptoms at onset on the time from MS onset to assignment of scores 6 or 7 or on the time from the assignment of a score of 6 to the assignment of a score of 7.

A new estrogen receptor on ER-negative breast cancer?

10604

Background: Premenopausal women and BRCA-1 mutation carriers have estrogen receptor-negative (ER-) breast cancers that paradoxically seem responsive to hormonal deprivation such as oophorectomy. GPR30 is a G protein-coupled receptor that is activated not only by estradiol but also tamoxifen and fulvestrant. The prevalence and significance of GPR30 in breast cancer are unknown. We hypothesized that GPR30 may be present in ER-negative tumors and may promote growth of ER-negative breast cancer in premenopausal patients. Methods: An immunohistochemical staining protocol for rabbit polyclonal GPR30 antibody (Novus Biological) was developed initially on the known GPR30-positive breast cancer cell line MCF-7 and the GPR30-negative breast cancer cell line MDA-MB-231 and later on a panel of human breast tumors from archived paraffin blocks. After an automated protocol was optimized, under an IRB-approved protocol all incoming breast cancer specimens were stained for GPR30 and reviewed by a pathologist blinded to the ER/PR status. Significance of associations was tested by chi square analysis. Results: Twenty-seven breast cancer tumors were studied. The mean age of the patients was 53 (range 20–87). All of 10 triple negative (ER-,PR-, HER2 neu-) and 2 ER-/Her2 neu+ tumors stained positive for GPR30. Only 4 of 11 ER+/Her2neu - tumors stained positive for GPR30 (p=0.004). The mean age of triple negative patients was 43.7 yr, while the mean age of ER+/Her2 neu- was 63.2 (p=0.02). Three out of 4 ER+/HER2 neu+ tumors stained positive for GPR30. Four patients were African Americans, 2 had triple negative tumors and 2 ER+/Her2+, all 4 were positive for GPR30. Conclusions: GPR30 appears to be frequently expressed in ER-negative breast cancer and may represent an adverse factor. ER+ tumors with good prognostic features (PR+, HER2 neu-) were mostly negative for GPR30, while high-risk tumors were positive for GRP30. Premenopausal status and African-American race are known risk factors for lower survival. In this study, the African-American patients had high-risk tumors that were also positive for GPR30. A longer- range study is needed to test the association of GPR30 expression with recurrence and death. Future studies to assess the function of GPR30 in breast cancer cells may yield prognostic and therapeutic applications.

No significant financial relationships to disclose.

Clinical follow-up of 304 patients with multiple sclerosis three years after mitoxantrone treatment

The objectives of this study were to assess the benefits of 1) mitoxantrone after three years of follow-up and 2) disease-modifying treatment (DMT) after stopping mitoxantrone. A retrospective analysis was performed on 304 patients with active relapsing-remitting (RR) or progressive multiple sclerosis (PMS) who were treated with mitoxantrone. After mitoxantrone therapy, some patients received DMT (interferon-beta or glatiramer acetate) while others did not. The disease course of the two groups was evaluated by the Expanded Disability Status Scale (EDSS) before and after mitoxantrone and then every year for three years. The mean EDSS score at starting mitoxantrone and three years after stopping mitoxantrone respectively, were: 3.3 (1.3) and 3.2 (1.7) for the RRMS patients and 5.9 (1.2) and 6.4 (1.4) for the PMS patients. Before starting mitoxantrone, demographic and clinical parameters of predictive disability were not significantly different between patients who received DMT or not. The variation of EDSS between time of stopping mitoxantrone and three years later was significantly different (+0.9 versus +0.3; P=0.03) for patients with RRMS. We found that mitoxantrone treatment induces stable disease up to two years after discontinuation of mitoxantrone therapy. In the third year, patients without DMT deteriorated.

Broad screening of the legume family for variability in seed insecticidal activities and for the occurrence of the A1b-like knottin peptide entomotoxins

Pea albumin 1b (PA1b) is a small sulphur-rich peptide from pea seeds, also named leginsulin because of the binding characteristics of its soybean orthologue. Its insecticidal properties were discovered more recently. By using a combination of molecular, biochemical and specific insect bioassays on seed extracts, we characterised genes from numerous Papilionoideae, but not from Caesalpinioideae or Mimosoideae, although the last group harboured species with partially positive cues (homologous biological activities). The A1b defence peptide family, therefore, appears to have evolved relatively late in the legume lineage, maybe from the sophoroid group (e.g. Styphnolobium japonicum). However, unambiguous sequence information is restricted to a group of tribes within the subfamily Papilionoideae (Psoraleae, Millettieae, Desmodieae, Hedysareae, Phaseoleae, Vicieae, and the now clearly polyphyletic "Trifolieae" and "Galegeae"). Recent diversification by gene duplications has occurred in many species, or longer ago in some lineages (Medicago truncatula), as well as probable gene or expression losses at different taxonomic levels (Loteae, Vigna subterranea).

Circadian rhythms of isoprene biosynthesis in grey poplar leaves

Isoprene (2-methyl-1,3-butadiene) emission varies diurnally in different species. In poplar (Populus spp.), it has recently been shown that the gene encoding the synthesizing enzyme for isoprene, isoprene synthase (ISPS), displays diurnal variation in expression. Working on shoot cultures of Grey poplar (Populus x canescens) placed under a different light regime in phytochambers, we showed that these variations in PcISPS gene expression, measured by quantitative real-time polymerase chain reaction, are not only due to day-night changes, but also are linked to an internal circadian clock. Measurement of additional selected isoprenoid genes revealed that phytoene synthase (carotenoid pathway) displays similar fluctuations, whereas 1-deoxy-d-xylulose 5-phosphate reductoisomerase, possibly the first committed enzyme of the 1-deoxy-d-xylulose 5-phosphate pathway, only shows light regulation. On the protein level, it appeared that PcISPS activity and protein content became reduced under constant darkness, whereas under constant light, activity and protein content of this enzyme were kept high. In contrast, isoprene emission rates under continuous irradiation displayed circadian changes as is the case for gene expression of PcISPS. Furthermore, binding assays with Arabidopsis (Arabidopsis thaliana) late elongated hypocotyl, a transcription factor of Arabidopsis involved in circadian regulation, clearly revealed the presence of circadian-determining regulatory elements in the promoter region of PcISPS.

Humoral and cellular responses to influenza vaccination in human recipients naturally tolerant to a kidney allograft

Rare kidney allograft recipients enjoy unaltered graft function years after interruption of their immunosuppressive treatment. To assess the extent to which this state of 'operational tolerance' (TOL) is specific to the graft and not the result of a global immunodeficiency, we analyzed the response of such patients following influenza vaccination. Hemagglutination inhibition titers and frequency of IFNgamma-secreting T cells were measured before 1 and 3 months after vaccination. The proportion of healthy volunteers (HV) responding to vaccine was significantly higher than that of immunosuppressed (IS) patients. Three 'TOL' patients presented a humoral response similar to that of HV, whereas the two others had a poor response, like the IS recipients. Although the small number of patients does not allow for definitive conclusions to be made, these data suggest that the status of tolerance may be heterogeneous, with some patients with a global immunodeficiency and others with an adapted response to vaccination.

Structural organization and expression of human MTUS1, a candidate 8p22 tumor suppressor gene encoding a family of angiotensin II AT2 receptor-interacting proteins, ATIP

The Mitochondrial Tumor suppressor 1 (MTUS1) gene is a newly identified candidate tumor suppressor gene at chromosomal position 8p22. We report here that MTUS1 encodes a family of proteins whose leader member (ATIP1) was previously isolated in our laboratory as a novel interacting partner of the angiotensin II AT2 receptor involved in growth inhibition (Nouet, JBC 279: 28989-97, 2004). The MTUS1 gene contains 17 coding exons distributed over 112 kb of genomic DNA. Alternative exon usage generates three major transcripts (ATIP1, ATIP3 and ATIP4), each showing different tissue distribution. ATIP polypeptides are identical in their carboxy-terminal region carrying four coiled-coil domains. In their amino-terminal portion, ATIP polypeptides exhibit distinct motifs for localisation in the cytosol, nucleus or cell membrane, suggesting that MTUS1 gene products may be involved in a variety of intracellular functions in an AT2-dependent and independent manner. ATIP1 is ubiquitous and highly expressed in the brain. ATIP3 is the major transcript in tissues (prostate, bladder, breast, ovary, colon) corresponding to cancer types with frequent loss of heterozygosity at 8p22. Interestingly, ATIP4 is a brain-specific transcript highly abundant in the cerebellum and fetal brain. High evolutionary conservation of ATIP amino-acid sequences suggests important biological roles for this new family of proteins in tumor suppression and/or brain function.

Mutation analysis of the 8p22 candidate tumor suppressor gene ATIP/MTUS1 in hepatocellular carcinoma

A high frequency of allelic loss affecting chromosome 8p and a minimal region of deletion at p21-22 have been previously reported in hepatocellular carcinoma (HCC), suggesting that at least one tumor suppressor gene is present in this region. In this study, we assessed whether the angiotensin II AT2 receptor interacting protein (ATIP)/mitochondrial tumor suppressor gene (MTUS1), a gene newly identified at position 8p22, may be a candidate tumor suppressor gene mutated in HCC. We searched for alterations in the 17 coding exons of ATIP/MTUS1 by means of denaturating high-performance liquid chromatography and sequencing, in 51 HCC tumors and 58 cell lines for which loss of heterozygosity status was known. Five major nucleotide substitutions were identified, all located in exons used by the ATIP3 transcript which is the only ATIP transcript variant expressed in liver. These nucleotide variations result in amino-acid substitution or deletion of conserved structural motifs (nuclear localisation signal, polyproline motif, leucine zipper) and also affect exonic splicing enhancer motifs and physiological splice sites, suggesting potential deleterious effects on ATIP3 function and/or expression.

Diurnal and seasonal variation of isoprene biosynthesis-related genes in grey poplar leaves

Transcript levels of mRNA from 1-deoxy-D-xylulose 5-phosphate reductoisomerase (PcDXR), isoprene synthase (PcISPS), and phytoene synthase (PcPSY) showed strong seasonal variations in leaves of Grey poplar (Populus x canescens [Aiton] Sm.). These changes were dependent on the developmental stage and were strongly correlated to temperature and light. The expression rates of the genes PcDXR and PcISPS were found to be significantly correlated to each other, whereas the expression of the PcPSY gene showed a different seasonal pattern. Protein concentration and enzyme activity of PcISPS showed distinct seasonal patterns peaking in late summer, whereas highest transcription levels of PcISPS were observed in early summer. Moreover, correlation between PcISPS protein concentration and enzyme activity changed, in particular in autumn, when PcISPS protein levels remained high while enzyme activity declined, indicating posttranslational modifications of the enzyme. The positive correlation between dimethylallyl diphosphate levels and PcISPS protein content was found to be consistent with the demonstrated synchronized regulation of PcDXR and PcISPS, suggesting that metabolic flux through the 1-deoxy-D-xylulose 5-phosphate pathway and isoprene emission capacity are closely intercoordinated. Transcript levels of PcISPS showed strong diurnal variation with maximal values before midday in contrast to PcDXR, whose gene expression exhibited no clear intraday changes. During the course of a day, in vitro PcISPS activities did not change, whereas leaf dimethylallyl diphosphate levels and isoprene emission showed strong diurnal variations depending on actual temperature and light profiles on the respective day. These results illustrate that the regulation of isoprene biosynthesis in Grey poplar leaves seems to happen on transcriptional, posttranslational, and metabolic levels and is highly variable with respect to seasonal and diurnal changes in relation to temperature and light.

Expression of E-cadherin in human colorectal cancer

AIM

To investigate the expression of E-cadherin, a calcium-dependent cell-cell adhesion molecule in colorectal carcinoma. Antibodies to E-Cadherin were used to establish the association of their expression with the clinicopathological characteristics of this disease using immunohistochemical methods.

METHODS

Immunohistochemical analysis for E-cadherin was carried out in formalin-fixed, paraffin-embedded sections of neoplastic colorectal tissues and non-neoplastic ones adjacent to the lesion from 49 patients who underwent surgery, by the standard peroxidase-antiperoxidase method. Expression of this antigen in normal and malignant epithelium and stromal cells was compared.

RESULTS

Both neoplastic and normal tissues showed expression of E-cadherin. There was, however, higher expression of E-cadherin in epithelial cells in both tumour and normal tissues than stromal cells. The percentage of expression in epithelial cells of well-differentiated tumours was significantly higher than moderately differentiated tumours. Loss of normal membranous expression and the presence of cytoplasmic and mixed staining were found frequently in tumour tissues (p = 0.004). This loss of membranous expression, however, did not correlate with Duke's staging, tumour grade, sex, size or site of the tumour.

CONCLUSION

This study suggests that the lower expression of E-cadherin in less differentiated tumours may explain their aggressive nature, although loss of membranous expression was not significantly correlated to Duke's staging, tumour grade, sex, size and site of tumour.