Diabetes mellitus, a microRNA-related disease?

Diabetes mellitus is a complex disease resulting in altered glucose homeostasis. In both type 1 and type 2 diabetes mellitus, pancreatic β cells cannot secrete appropriate amounts of insulin to regulate blood glucose level. Moreover, in type 2 diabetes mellitus, altered insulin secretion is combined with a resistance of insulin-target tissues, mainly liver, adipose tissue, and skeletal muscle. Both environmental and genetic factors are known to contribute to the development of the disease. Growing evidence indicates that microRNAs (miRNAs), a class of small noncoding RNA molecules, are involved in the pathogenesis of diabetes. miRNAs function as translational repressors and are emerging as important regulators of key biological processes. Here, we review recent studies reporting changes in miRNA expression in tissues isolated from different diabetic animal models. We also describe the role of several miRNAs in pancreatic β cells and insulin-target tissues. Finally, we discuss the possible use of miRNAs as blood biomarkers to prevent diabetes development and as tools for gene-based therapy to treat both type 1 and type 2 diabetes mellitus.

Radioimmunotherapy of colorectal cancer liver metastases: combination with radiotherapy.

The expected therapeutic gain of a combined radioimmunotherapy (RIT) with conventional radiotherapy (RT) would be a synergy of tumor irradiation, provided that toxic, dose-limiting side effects concern different organs. We have shown in a model of subcutaneous human colon cancer transplants in nude mice that RIT with 131I-labeled anti-CEA antibody fragments combined with fractionated RT give an additive therapeutic effect without increase of side effects. A second study of different timing schedules of RIT and RT has shown that close association of both therapies without delay is more efficient than a therapy with a treatment-free interval of two weeks. In a new model of human colon cancer liver metastases in nude mice, early treatment with RIT and with RT has been curative, whereas therapies initiated later were less efficient, suggesting that the combined therapy is likely to be more efficient in an adjuvant situation after surgery. At the clinical level, six patients with limited liver metastatic disease from colorectal cancer were treated with RIT using 200 mCi 131I-labeled anti-CEA MAb F(ab')2 fragments combined with fractionated external beam RT of 20 Gy to the entire liver. As expected, spontaneously reversible bone marrow toxicity grade 3 to 4 and reversible liver toxicity grade 1 to 3 have been observed. By computerized tomography, three patients showed stable disease and one patient partial remission, whereas two patients had progressive disease. In conclusion, animal experiments have shown a clear advantage of combined RT and RIT, and the clinical study shows the feasibility of such a therapy in patients with colorectal cancer liver metastases.

Systematic Assessment of Factors Influencing Preferences of Crohn's Disease Patients in Selecting an Anti-TNF agent (CHOOSE TNF TRIAL)

Background a nd A ims: I nfliximab (IFX), adalimumab (ADA)and certolizumab pegol (CZP) have similar efficacy for inductionand maintenance of clinical response and remission in Crohn'sdisease (CD). Given the comparable nature of t hese drugs,patients' p references m ay i nfluence the choice o f the product.Goal: to identify factors contributing to CD patients' decision inselecting one anti-TNF agent over the others.Methods: A p rospectdive s urvey was performed a mong a nti-TNF-naïve CD patients. Prior to completion of a questionnaire,patients were provided with a description of the three anti-TNFagents f ocusing on indications, route of administration, s ideeffects, and scientific evidence of efficacy and safety.Results: One hundred patients (47f/53m, mean age 45±16yrs)completed the questionnaire. Disease location was ileal, colonicand ileocolonic in 33%, 40% and 27% of patients, respectively.Thirty-six percent preferred ADA as medication of choice, while28% and 2 5% p referred CZP and IFX; 11% were u ndecided.Patients' decision in selecting an anti-TNF drug was influencedby t he following f actors: side effects ( 76%), p hysician'srecommendation (66%), route of administration (54%), efficacydata (52%), time required for therapy administration (27%),recommendations by other CD patients (21%) and interactionswith other medications (12%).Conclusions: T he majority of p atients p referred anti-TNFmedications t hat were a dministered by s ubcutaneous i njectionrather t han b y intravenous i nfusion. Side effect profile andphysicians' r ecommendation are t wo m ajor factors influencingthe patients' s election of a specific anti-TNF d rug. Patients'concerns about safety and lifestyle habits should be taken intoaccount when prescribing anti-TNF drugs.

Recommandations de vaccination pour les patients atteints de maladie chronique [Immunization guidelines regarding patients with a chronic disease].

Some chronic diseases--like renal failure, liver insufficiency, chronic lung disease, cardiac involvement, diabetes mellitus, asplenia--present limited defects of the immune system and/or a higher risk of infection; therefore, patients with such pathologies should get selective vaccinations. The efficacy of immunization decreases with disease progression; for this reason, these patients should be immunized as soon as possible. At the beginning of their disease, these patients do not need a specialized treatment and are followed by the general practitioner alone who is in charge of immunizing them as well as contact people of any immunocompromised patient. OFSP's regular vaccinations programme is recommended, as well as selective vaccinations against influenza, pneumococci and viral hepatitis, depending on the underlying chronic disease.

Transcript profiling suggests that differential metabolic adaptation of mice to a high fat diet is associated with changes in liver to muscle lipid fluxes.

Genetically homogenous C57Bl/6 mice display differential metabolic adaptation when fed a high fat diet for 9 months. Most become obese and diabetic, but a significant fraction remains lean and diabetic or lean and non-diabetic. Here, we performed microarray analysis of "metabolic" transcripts expressed in liver and hindlimb muscles to evaluate: (i) whether expressed transcript patterns could indicate changes in metabolic pathways associated with the different phenotypes, (ii) how these changes differed from the early metabolic adaptation to short term high fat feeding, and (iii) whether gene classifiers could be established that were characteristic of each metabolic phenotype. Our data indicate that obesity/diabetes was associated with preserved hepatic lipogenic gene expression and increased plasma levels of very low density lipoprotein and, in muscle, with an increase in lipoprotein lipase gene expression. This suggests increased muscle fatty acid uptake, which may favor insulin resistance. In contrast, the lean mice showed a strong reduction in the expression of hepatic lipogenic genes, in particular of Scd-1, a gene linked to sensitivity to diet-induced obesity; the lean and non-diabetic mice presented an additional increased expression of eNos in liver. After 1 week of high fat feeding the liver gene expression pattern was distinct from that seen at 9 months in any of the three mouse groups, thus indicating progressive establishment of the different phenotypes. Strikingly, development of the obese phenotype involved re-expression of Scd-1 and other lipogenic genes. Finally, gene classifiers could be established that were characteristic of each metabolic phenotype. Together, these data suggest that epigenetic mechanisms influence gene expression patterns and metabolic fates.

Cholesterol and Fatty Acids Regulate Dynamic Caveolin Trafficking through the Golgi Complex and between the Cell Surface and Lipid Bodies

Caveolins are a crucial component of plasma membrane (PM) caveolae but have also been localized to intracellular compartments, including the Golgi complex and lipid bodies. Mutant caveolins associated with human disease show aberrant trafficking to the PM and Golgi accumulation. We now show that the Golgi pool of mainly newly synthesized protein is detergent-soluble and predominantly in a monomeric state, in contrast to the surface pool. Caveolin at the PM is not recognized by specific caveolin antibodies unless PM cholesterol is depleted. Exit from the Golgi complex of wild-type caveolin-1 or -3, but not vesicular stomatitis virus-G protein, is modulated by changing cellular cholesterol levels. In contrast, a muscular dystrophy-associated mutant of caveolin-3, Cav3P104L, showed increased accumulation in the Golgi complex upon cholesterol treatment. In addition, we demonstrate that in response to fatty acid treatment caveolin can follow a previously undescribed pathway from the PM to lipid bodies and can move from lipid bodies to the PM in response to removal of fatty acids. The results suggest that cholesterol is a rate-limiting component for caveolin trafficking. Changes in caveolin flux through the exocytic pathway can therefore be an indicator of cellular cholesterol and fatty acid levels.

Mitochondrial Fatty Acid Oxidation in Obesity

Significance: Current lifestyles with high-energy diets and little exercise are triggering an alarming growth in obesity. Excess of adiposity is leading to severe increases in associated pathologies, such as insulin resistance, type 2 diabetes, atherosclerosis, cancer, arthritis, asthma, and hypertension. This, together with the lack of efficient obesity drugs, is the driving force behind much research. Recent Advances: Traditional anti-obesity strategies focused on reducing food intake and increasing physical activity. However, recent results suggest that enhancing cellular energy expenditure may be an attractive alternative therapy. Critical Issues: This review evaluates recent discoveries regarding mitochondrial fatty acid oxidation (FAO) and its potential as a therapy for obesity. We focus on the still controversial beneficial effects of increased FAO in liver and muscle, recent studies on how to potentiate adipose tissue energy expenditure, and the different hypotheses involving FAO and the reactive oxygen species production in the hypothalamic control of food intake. Future Directions: The present review aims to provide an overview of novel anti-obesity strategies that target mitochondrial FAO and that will definitively be of high interest in the future research to fight against obesity-related disorders. Antioxid. Redox Signal. 00, 000000.

Fsp27/CIDEC is a CREB target gene induced during early fasting in liver and regulated by FA oxidation rate

FSP27 (CIDEC in humans) is a protein associated with lipid droplets that downregulates the fatty acid oxidation (FAO) rate when it is overexpressed. However, little is known about its physiological role in liver. Here, we show that fasting regulates liver expression of Fsp27 in a time-dependent manner. Thus, during the initial stages of fasting a maximal induction of 800-fold was achieved, while during the later phase of fasting, Fsp27 expression decreased. The early response to fasting can be explained by a canonical PKA-CREB-CRTC2 signaling pathway since: i) CIDEC expression was induced by forskolin, ii) Fsp27 promoter activity was increased by CREB, and iii) Fsp27 expression was upregulated in the liver of Sirt1 knockout animals. Interestingly, pharmacological (etomoxir) or genetic (Hmgcs2 interference) inhibition of the FAO rate increases the in vivo expression of Fsp27 during fasting. Similarly, CIDEC expression was upregulated in HepG2 cells by either etomoxir or HMGCS2 interference. Our data indicate that there is a kinetic mechanism of auto-regulation between short- and long-term fasting, by which free fatty acids delivered to the liver during early fasting are accumulated/exported by FSP27/CIDEC, while over longer periods of fasting they are degraded in the mitochondria through the carnitine palmitoyl transferase (CPT) system.

Gas6 deficiency in recipient mice of allogeneic transplantation alleviates hepatic graft-versus-host disease.

Growth arrest-specific gene 6 (Gas6) is expressed in antigen-presenting cells and endothelial cells (ECs) but not in T cells. When wild-type (WT) or Gas6(-/-) mice received allogeneic non-T cell-depleted bone marrow cells, hepatic graft-versus-host disease (GVHD) was alleviated in Gas6(-/-) recipients regardless of donor genotype, but not in WT recipients. T-cell infiltration was more prominent and diffuse in WT than in Gas6(-/-) recipients' liver. When mice received 0.5 x 10(6) allogeneic T cells with T cell-depleted allogeneic bone marrow, clinical signs indicated that GVHD was less severe in Gas6(-/-) than in WT recipients, as shown by a significant improvement of the survival and reduced liver GVHD. These data demonstrate that donor cells were not involved in the protection mechanism. In addition, lack of Gas6 in antigen-presenting cells did not affect WT or Gas6(-/-) T-cell proliferation. We therefore assessed the response of WT or Gas6(-/-) ECs to tumor necrosis factor-alpha. Lymphocyte transmigration was less extensive through Gas6(-/-) than WT ECs and was not accompanied by increases in adhesion molecule levels. Thus, the lack of Gas6 in ECs impaired donor T-cell transmigration into the liver, providing a rationale for considering Gas6 pathway as a potential nonimmunosuppressive target to minimize GVHD in patients receiving allogeneic hematopoietic stem cell transplantation.

Silver-assisted laser desorption ionization for high spatial resolution imaging mass spectrometry of olefins from thin tissue sections.

Silver has been demonstrated to be a powerful cationization agent in mass spectrometry (MS) for various olefinic species such as cholesterol and fatty acids. This work explores the utility of metallic silver sputtering on tissue sections for high resolution imaging mass spectrometry (IMS) of olefins by laser desorption ionization (LDI). For this purpose, sputtered silver coating thickness was optimized on an assorted selection of mouse and rat tissues including brain, kidney, liver, and testis. For mouse brain tissue section, the thickness was adjusted to 23 ± 2 nm of silver to prevent ion suppression effects associated with a higher cholesterol and lipid content. On all other tissues, a thickness of at 16 ± 2 nm provided the best desorption/ionization efficiency. Characterization of the species by MS/MS showed a wide variety of olefinic compounds allowing the IMS of different lipid classes including cholesterol, arachidonic acid, docosahexaenoic acid, and triacylglyceride 52:3. A range of spatial resolutions for IMS were investigated from 150 μm down to the high resolution cellular range at 5 μm. The applicability of direct on-tissue silver sputtering to LDI-IMS of cholesterol and other olefinic compounds presents a novel approach to improve the amount of information that can be obtained from tissue sections. This IMS strategy is thus of interest for providing new biological insights on the role of cholesterol and other olefins in physiological pathways or disease.

Pharmacodynamic, pharmacokinetic and pharmacogenetic aspects of drugs used in the treatment of Alzheimer's disease.

With the aging population and its rapidly increasing prevalence, dementia has become an important public health concern in developed and developing countries. To date, the pharmacological treatment is symptomatic and based on the observed neurotransmitter disturbances. The four most commonly used drugs are donepezil, galantamine, rivastigmine and memantine. Donepezil, galantamine and rivastigmine are acetylcholinesterase inhibitors with different pharmacodynamic and pharmacokinetic profiles. Donepezil inhibits selectively the acetylcholinesterase and has a long elimination half-life (t½) of 70 h. Galantamine is also a selective acetylcholinesterase inhibitor, but also modulates presynaptic nicotinic receptors. It has a t½ of 6-8 h. Donepezil and galantamine are mainly metabolised by cytochrome P450 (CYP) 2D6 and CYP3A4 in the liver. Rivastigmine is a so-called 'pseudo-irreversible' inhibitor of acetylcholinesterase and butyrylcholinesterase. The t½ of the drug is very short (1-2 h), but the duration of action is longer as the enzymes are blocked for around 8.5 and 3.5 h, respectively. Rivastigmine is metabolised by esterases in liver and intestine. Memantine is a non-competitive low-affinity antagonist of the NMDA receptor with a t½ of 70 h. Its major route of elimination is unchanged via the kidneys. Addressing the issue of inter-patient variability in treatment response might be of special importance for the vulnerable population taking anti-dementia drugs. Pharmacogenetic considerations might help to avoid multiple medication changes due to non-response and/or adverse events. Some pharmacogenetic studies conducted on donepezil and galantamine reported an influence of the CYP2D6 genotype on the pharmacokinetics of the drugs and/or on the response to treatment. Moreover, polymorphisms in genes of the cholinergic markers acetylcholinesterase, butyrylcholinesterase, choline acetyltransferase and paraoxonase were found to be associated with better clinical response to acetylcholinesterase inhibitors. However, confirmation studies in larger populations are necessary to establish evidence of which subgroups of patients will most likely benefit from anti-dementia drugs. The aim of this review is to summarize the pharmacodynamics and pharmacokinetics of the four commonly used anti-dementia drugs and to give an overview on the current knowledge of pharmacogenetics in this field.

Alzheimer disease: curly fibers and tangles in organs other than brain.

The filamentous brain lesions that define Alzheimer disease (AD) consist of senile plaques and neurofibrillary tangles. Undulated pathological filaments--curly fibers or neuropil threads--also occur in the neuropil. Beta-amyloid precursor proteins are synthesized by many cells outside the central nervous system and recently, deposition of beta-amyloid-protein was reported to occur in non-neuronal tissues. In addition, increasing data claim the importance of chronic inflammation in the pathogenesis of AD. These observations suggest that AD may be a widespread systemic disorder. Here we report that pathological argyrophilic filaments with histochemical properties of amyloid showing striking morphological similarity to curly fibers and/or tangles accumulate not only in ependymal layer and in epithelial cells of choroid plexus, but also in several other organs (e.g. liver, pancreas, ovary, testis, thyroid) in AD. The ependyma, choroid plexus, and various organs of 39 autopsy cases were analyzed. In search of curly fiber and tangle-like changes in organs other than brain, 395 blocks from 21 different tissues of 24 AD cases, 5 cases with discrete or moderate AD-type changes, and 10 control cases were investigated. We found in non-neuronal cells "curly fibers" or "tangles" immunoreactive with antibodies to P component, Tau-protein, ubiquitin, fibronectin, and Apolipoprotein-E, but lacking immunoreactivity with antibodies to neurofilament proteins. Ultrastructurally they consist of densely packed straight and paired helical filaments and closely resemble neurofibrillary tangles and neuropil threads. These observations indicate that the formation of "curly fibers" and "tangles" is not unique to the central nervous system. The results suggest that AD might be a systemic disorder or that similar fibrillary changes to tangles and curly fibers may also be associated with other amyloidosis than beta-amyloidosis. Further investigations are necessary to understand the pathogenetic interest of these fibrillary changes outside the CNS.

Discriminating Irritable Bowel Syndrome fromInflammatory Bowel Disease: what is the Role of Biomarkers in Daily Practice?

Background a nd A ims: D iscriminating irritable bowelsyndrome (IBS) from inflammatory bowel disease (IBD) can bea clinical c hallenge as s ymptoms c an overlap. We a nd othershave recently shown that fecal c alprotectin ( FC) is moreaccurate for d iscriminating IBS f rom IBD compared to C -reactive p rotein ( CRP) and b lood leukocytes. We a imed toassess which b iomarkers are used by g astroenterologists intheir daily practice for discriminating IBS from IBD.Methods: A q uestionnaire was sent to all board certifiedgastroenterologists in Switzerland in July 2010.Results: Response rate was 57% (153/270). Mean physician'sage was 50±9years, mean duration o f gastroenterologicpractice 1 4±8years, 52% of them were working in p rivatepractice a nd 48% in h ospitals. T he following biomarkers weredetermined for discriminating IBS from IBD: CRP 100%, FC79%, hematogram (red blood cells and leukocytes) 70%, ironstatus ( ferritin, t ransferrin s aturation) 59%, e rythrocytesedimentation rate 2.7%, protein electrophoresis 0.7%, andalpha-1 antitrypsin clearance 0.7%. There was a trend for usingFC more often in p rivate practice t han in h ospital ( P = 0.08).Eighty-nine percent of gastroenterologists considered FC to besuperior to CRP for discriminating IBS from IBD, 8 7% thoughtthat patient's compliance for fecal sampling is high, and 51%judged the fee of USD 60 for a FC test as appropriate.Conclusions: F C is widely used in c linical practice t odiscriminate IBS from IBD. In accordance with the scientificevidence, the majority of gastroenterologists consider FC to bemore accurate than CRP for discriminating IBS from IBD.