The impact of iron coagulant on the behavior and biochemistry of freshwater mussels Anodonta cygnea and Unio tumidus during lake restoration

Iron (Fe) treatment is one of the most commonly used methods to restore eutrophic lakes and reservoirs. The Fe-based coagulants dosage results in an almost immediate improvement in water quality at a relatively low cost. However, the effects of the application of coagulants are not always predictable, and the scale of the risks is not fully understood. The dosage of coagulants changes the chemical and physical properties of water, thereby affecting aquatic biocenoses. In this study, several laboratory experiments were conducted to evaluate the effects of Fe-based coagulant dosage on two bivalves species: Anodonta anatina and Unio tumidus. Their ability to efficiently filter water and reduce seston makes them a key component of aquatic ecosystems in terms of maintaining proper ecological health and stable functioning. Behavioral response, biochemical parameters, and body chemistry changes in mussels exposed to different doses of coagulant were surveyed. A dose-dependent reduction in filtration activity of both species was observed. As early as 10 g Fe m² (which is a moderate dose used in lakes restoration), mussels of both species almost completely reduced their filtration activity and remained with closed valves for several subsequent days. Significant Fe accumulation in muscles of bivalves exposed to coagulant was also observed. This was particularly the case when very high doses of coagulant were applied. Then, the iron content in leg muscles of both species increased over fourfold. At the same time, a decrease in muscles calcium and phosphorus content was observed. No symptoms of oxidative stress (TBARS, H₂O₂) after mussels exposure to coagulants were found. The results suggest that the application of Fe-based coagulant for water ecosystem restoration may be a threat to the mussels population. These findings are significant for decisions on the selection of restoration methods for a specific lake.

Isoprenaline modified the lipidomic profile and reduced β-oxidation in HL-1 cardiomyocytes: In vitro model of takotsubo syndrome

Recent studies have suggested a pathogenetic link between impaired mitochondria and Takotsubo syndrome (TTS), which is closely connected with catecholamine overstimulation, poor outcomes, and changes in lipid metabolism. We investigated the changes in lipid metabolism at the level of fatty acid β-oxidation and changes in the intracellular lipidomic spectrum. The immortalized cell line of HL-1 cardiomyocytes was used in this study as an established in vitro model of TTS. The cells were exposed to the non-selective β-agonist isoprenaline (ISO) for acute (2 h) and prolonged (24 h) periods. We investigated the impact on mitochondrial adenosine 5’-triphosphate (ATP) production and β-oxidation using real-time cell metabolic analysis, total lipid content, and changes in the lipidomic spectrum using high-performance liquid chromatography (HPLC) and mass spectrometry. Furthermore, modifications of selected lipid transporters were determined using real-time – polymerase chain reaction (RT-PCR) and/or Western blot techniques. By choosing this wide range of targets, we provide a detailed overview of molecular changes in lipid metabolism during catecholamine overstimulation. The present study demonstrates that acute exposure to ISO decreased ATP production by up to 42.2%, and prolonged exposure to ISO decreased β-oxidation by 86.4%. Prolonged exposure to ISO also increased lipid accumulation by 4%. Lipid spectrum analysis of prolonged exposure to ISO showed a reduced concentration of cardioprotective and an increased concentration of lipotoxic lipid molecules during long-term exposure. Decreased lipid utilization can lead to higher intracellular lipid accumulation and the formation of lipotoxic molecules. Changes in the lipid spectrum can induce pathophysiological signaling pathways leading to cardiomyocyte remodeling or apoptosis. Thus, changes in lipid metabolism induced by excessive doses of catecholamines may cause TTS and contribute to a progression of heart failure, which is at increased risk after a TTS episode.

Hypoxia-Induced Sarcoplasmic Reticulum Ca2+ Leak Is Reversed by Ryanodine Receptor Stabilizer JTV-519 in HL-1 Cardiomyocytes

Background:

To assess whether hypoxia, as can be found in obstructive sleep apnea syndrome, is causally associated with the development of heart failure through a direct effect on calcium leakage from the sarcoplasmic reticulum.

Methods:

The impact of hypoxia on sarcoplasmic reticulum calcium leakage and expression of RyR2 (ryanodine receptor2) and SERC2a (sarcoplasmic reticulum Ca²⁺ATPase 2a) was investigated together with the outcomes of JTV-519 and S107 treatment. HL-1 cardiomyocytes were cultured for 7 days on gas-permeable cultureware under control (12% O₂) or hypoxic (1% O₂) conditions with or without JTV-519 or S107. SRCL was assessed using a Fluo-5N probe. Gene and protein expression was analyzed using qPCR and western blotting.

Results:

Hypoxic exposure increased sarcoplasmic reticulum calcium leakage by 39% and reduced RyR2 gene expression by 52%. No effect on RyR2 protein expression was observed. Treatment with 1µM JTV-519 reduced sarcoplasmic reticulum calcium leakage by 52% and 35% under control and hypoxic conditions, respectively. Administration of 1 µM JTV-519 increased RyR2 gene expression by 89% in control conditions. No effect on SRCL, RyR2, or SERC2a gene, or protein expression was observed with S107 treatment.

Conclusion:

Hypoxia increased sarcoplasmic reticulum calcium leakage which was ameliorated by JTV-519 treatment independently of gene or protein expression. JTV-519 represents a possible treatment for obstructive sleep apnea-associated HF.

Hypoxia Induces Saturated Fatty Acids Accumulation and Reduces Unsaturated Fatty Acids Independently of Reverse Tricarboxylic Acid Cycle in L6 Myotubes

Obstructive sleep apnea syndrome, characterized by repetitive episodes of tissue hypoxia, is associated with several metabolic impairments. Role of fatty acids and lipids attracts attention in its pathogenesis for their metabolic effects. Parallelly, hypoxia-induced activation of reverse tricarboxylic acid cycle (rTCA) with reductive glutamine metabolism provides precursor molecules for de novo lipogenesis. Gas-permeable cultureware was used to culture L6-myotubes in chronic hypoxia (12%, 4% and 1% O₂) with ¹³C labelled glutamine and inhibitors of glutamine uptake or rTCA-mediated lipogenesis. We investigated changes in lipidomic profile, ¹³C appearance in rTCA-related metabolites, gene and protein expression of rTCA-related proteins and glutamine transporters, glucose uptake and lactate production. Lipid content increased by 308% at 1% O_2, predominantly composed of saturated fatty acids, while triacylglyceroles containing unsaturated fatty acids and membrane lipids (phosphatidylcholines, phosphatidylethanolamines, phosphatidylinositol) decreased by 20-70%. rTCA labelling of malate, citrate and 2-hydroxyglutarate increased by 4.7-fold, 2.2-fold and 1.9-fold in 1% O₂, respectively. ATP-dependent citrate lyase inhibition in 1% O₂ decreased lipid amount by 23% and increased intensity of triacylglyceroles containing unsaturated fatty acids by 56-80%. Lactate production increased with hypoxia. Glucose uptake dropped by 75% with progression of hypoxia from 4% to 1% O₂. Protein expression remained unchanged. Altogether, hypoxia modified cell metabolism leading to lipid composition alteration and rTCA activation.

Interaction of Diet/Lifestyle Intervention and TCF7L2 Genotype on Glycemic Control and Adiposity among Overweight or Obese Adults: Big Data from Seven Randomized Controlled Trials Worldwide

Objective. The strongest locus which associated with type 2 diabetes (T2D) by the common variant rs7903146 is the transcription factor 7-like 2 gene (TCF7L2). We aimed to quantify the interaction of diet/lifestyle interventions and the genetic effect of TCF7L2 rs7903146 on glycemic traits, body weight, or waist circumference in overweight or obese adults in several randomized controlled trials (RCTs).Methods. From October 2016 to May 2018, a large collaborative analysis was performed by pooling individual-participant data from 7 RCTs. These RCTs reported changes in glycemic control and adiposity of the variant rs7903146 after dietary/lifestyle-related interventions in overweight or obese adults. Gene treatment interaction models which used the genetic effect encoded by the allele dose and common covariates were applicable to individual participant data in all studies.Results. In the joint analysis, a total of 7 eligible RCTs were included (n = 4,114 ). Importantly, we observed a significant effect modification of diet/lifestyle-related interventions on the TCF7L2 variant rs7903146 and changes in fasting glucose. Compared with the control group, diet/lifestyle interventions were related to lower fasting glucose by -3.06 (95% CI, -5.77 to -0.36) mg/dL (test for heterogeneity and overall effect: I 2 = 45.1 % , p < 0.05 ; z = 2.20 , p = 0.028 ) per one copy of the TCF7L2 T risk allele. Furthermore, regardless of genetic risk, diet/lifestyle interventions were associated with lower waist circumference. However, there was no significant change for diet/lifestyle interventions in other glycemic control and adiposity traits per one copy of TCF7L2 risk allele.Conclusions. Our findings suggest that carrying the TCF7L2 T risk allele may have a modestly greater benefit for specific diet/lifestyle interventions to improve the control of fasting glucose in overweight or obese adults.

Intermittent Hypoxia Stimulates Lipolysis, But Inhibits Differentiation and De Novo Lipogenesis in 3T3-L1 Cells

Background: Exposure to intermittent hypoxia (IH) may play a role in the development of metabolic impairments in the context of obstructive sleep apnea syndrome, probably by elevated plasma levels of free fatty acids. Employing gas-permeable cultureware to grow differentiated human and mouse adipocytes in vitro, we directly studied the effects of pericellular oxygen fluctuations on key adipocyte metabolic functions-spontaneous lipolytic rates, triglyceride accumulation, de novo lipogenesis, and expression of adipocyte-specific marker genes. Materials and Methods: 3T3-L1 fibroblasts and human subcutaneous preadipocytes were differentiated under conditions that induced repetitive pericellular-oxygen cycles IH between 1% O₂ (5 min) and 16% O₂ (5 min), continuously for 14 days or under control conditions. Chemicals were used to inhibit the flux of acetyl-CoA from glycolysis (alfa-cyano-4-hydroxy cinnamate) or the tricarboxylic acid cycle (SB204990), or to stimulate the flux of acetyl-CoA from pyruvate to the lipogenic pool. Lipolytic rate, intracellular lipids, and expression of adipocyte differentiation markers were assessed and t-test or ANOVA were used to find significant differences. Results: The rate of lipolysis increased by 211% in 3T3-L1 cells and by 39% in obese human adipocytes. Exposure to IH reduced intracellular lipid stores by 37% and reduced the expression of adipocyte differentiation markers. Pharmacological stimulation or inhibition of de novo lipogenesis did not modify the intracellular lipid content under IH. Conclusions: Pericellular oxygen fluctuations directly stimulated lipolysis, but did not increase de novo lipogenesis from endogenous substrates. Similarly, IH hampered adipocyte differentiation from precursors.

Technical Feasibility and Physiological Relevance of Hypoxic Cell Culture Models

Hypoxia is characterized as insufficient oxygen delivery to tissues and cells in the body and is prevalent in many human physiology processes and diseases. Thus, it is an attractive state to experimentally study to understand its inner mechanisms as well as to develop and test therapies against pathological conditions related to hypoxia. Animal models in vivo fail to recapitulate some of the key hallmarks of human physiology, which leads to human cell cultures; however, they are prone to bias, namely when pericellular oxygen concentration (partial pressure) does not respect oxygen dynamics in vivo. A search of the current literature on the topic revealed this was the case for many original studies pertaining to experimental models of hypoxia in vitro. Therefore, in this review, we present evidence mandating for the close control of oxygen levels in cell culture models of hypoxia. First, we discuss the basic physical laws required for understanding the oxygen dynamics in vitro, most notably the limited diffusion through a liquid medium that hampers the oxygenation of cells in conventional cultures. We then summarize up-to-date knowledge of techniques that help standardize the culture environment in a replicable fashion by increasing oxygen delivery to the cells and measuring pericellular levels. We also discuss how these tools may be applied to model both constant and intermittent hypoxia in a physiologically relevant manner, considering known values of partial pressure of tissue normoxia and hypoxia in vivo, compared to conventional cultures incubated at rigid oxygen pressure. Attention is given to the potential influence of three-dimensional tissue cultures and hypercapnia management on these models. Finally, we discuss the implications of these concepts for cell cultures, which try to emulate tissue normoxia, and conclude that the maintenance of precise oxygen levels is important in any cell culture setting.

Fabrication of Bioengineered Skin by Injection Molding: A Feasibility Study on Automation

The use of bioengineered skin has facilitated fundamental and applied research because it enables the investigation of complex interactions between various cell types as well as the extracellular matrix. The predominantly manual fabrication of these living tissues means, however, that their quality, standardization, and production volume are extremely dependent on the technician's experience. Simple laboratory automation could facilitate the use of living tissues by a greater number of research groups. We developed and present here an injection molding technique for the fabrication of bilayered skin equivalents. The tissue was formed automatically by two separate injections into a customized mold to produce the dermal and epidermal skin layers. We demonstrated the biocompatibility of this fabrication process and confirmed the resulting bilayered morphology of the bioengineered skin using histology and immunohistochemistry. Our findings highlight the possibility of fabricating multilayered living tissue by injection molding, suggesting that further investigation into this automation method could result in the rapid and low-cost fabrication of standardized bioengineered skin.

A simplified fabrication technique for cellularized high-collagen dermal equivalents

Human autologous bioengineered skin has been successfully developed and used to treat skin injuries in a growing number of cases. In current clinical studies, the biomaterial used is fabricated via plastic compression of collagen hydrogel to increase the density and stability of the tissue. To further facilitate clinical adoption of bioengineered skin, the fabrication technique needs to be improved in terms of standardization and automation. Here, we present a one-step mixing technique using highly concentrated collagen and human fibroblasts to simplify fabrication of stable dermal equivalents. As controls, we prepared cellularized dermal equivalents with three varying collagen compositions. We found that the dermal equivalents produced using the simplified mixing technique were stable and pliable, showed viable fibroblast distribution throughout the tissue, and were comparable to highly concentrated manually produced collagen gels. Because no subsequent plastic compression of collagen is required in the simplified mixing technique, the fabrication steps and production time for dermal equivalents are consistently reduced. The present study provides a basis for further investigations to optimize the technique, which has significant promise in enabling efficient clinical production of bioengineered skin in the future.

Blockade of Endothelin-1 Receptor Type B Ameliorates Glucose Intolerance and Insulin Resistance in a Mouse Model of Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is associated with insulin resistance (IR) and glucose intolerance. Elevated endothelin-1 (ET-1) levels have been observed in OSA patients and in mice exposed to intermittent hypoxia (IH). We examined whether pharmacological blockade of type A and type B ET-1 receptors (ETA and ETB) would ameliorate glucose intolerance and IR in mice exposed to IH. Subcutaneously implanted pumps delivered BQ-123 (ETA antagonist; 200 nmol/kg/day), BQ-788 (ETB antagonist; 200 nmol/kg/day) or vehicle (saline or propyleneglycol [PG]) for 14 days in C57BL6/J mice (10/group). During treatment, mice were exposed to IH (decreasing the FiO2 from 20.9% to 6%, 60/h) or intermittent air (IA). After IH or IA exposure, insulin (0.5 IU/kg) or glucose (1 mg/kg) was injected intraperitoneally and plasma glucose determined after injection and area under glucose curve (AUC) was calculated. Fourteen-day IH increased fasting glucose levels (122 ± 7 vs. 157 ± 8 mg/dL, PG: 118 ± 6 vs. 139 ± 8; both p < 0.05) and impaired glucose tolerance (AUCglucose: 19,249 ± 1105 vs. 29,124 ± 1444, PG AUCglucose: 18,066 ± 947 vs. 25,135 ± 797; both p < 0.05) in vehicle-treated animals. IH-induced impairments in glucose tolerance were partially ameliorated with BQ-788 treatment (AUCglucose: 21,969 ± 662; p < 0.05). Fourteen-day IH also induced IR (AUCglucose: 7185 ± 401 vs. 8699 ± 401; p < 0.05). Treatment with BQ-788 decreased IR under IA (AUCglucose: 5281 ± 401, p < 0.05) and reduced worsening of IR with IH (AUCglucose: 7302 ± 401, p < 0.05). There was no effect of BQ-123 on IH-induced impairments in glucose tolerance or IR. Our results suggest that ET-1 plays a role in IH-induced impairments in glucose homeostasis.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

The Effect of Hypoxia and Metformin on Fatty Acid Uptake, Storage, and Oxidation in L6 Differentiated Myotubes

Metabolic impairments associated with obstructive sleep apnea syndrome (OSA) are linked to tissue hypoxia, however, the explanatory molecular and endocrine mechanisms remain unknown. Using gas-permeable cultureware, we studied the chronic effects of mild and severe hypoxia on free fatty acid (FFA) uptake, storage, and oxidation in L6 myotubes under 20, 4, or 1% O₂. Additionally, the impact of metformin and the peroxisome proliferator-activated receptor (PPAR) β/δ agonist, called GW501516, were investigated. Exposure to mild and severe hypoxia reduced FFA uptake by 37 and 32%, respectively, while metformin treatment increased FFA uptake by 39% under mild hypoxia. GW501516 reduced FFA uptake under all conditions. Protein expressions of CD36 (cluster of differentiation 36) and SCL27A4 (solute carrier family 27 fatty acid transporter, member 4) were reduced by 17 and 23% under severe hypoxia. Gene expression of UCP2 (uncoupling protein 2) was reduced by severe hypoxia by 81%. Metformin increased CD36 protein levels by 28% under control conditions and SCL27A4 levels by 56% under mild hypoxia. Intracellular lipids were reduced by mild hypoxia by 18%, while in controls only, metformin administration further reduced intracellular lipids (20% O₂) by 36%. Finally, palmitate oxidation was reduced by severe hypoxia, while metformin treatment reduced non-mitochondrial O₂ consumption, palmitate oxidation, and proton leak at all O₂ levels. Hypoxia directly reduced FFA uptake and intracellular lipids uptake in myotubes, at least partially, due to the reduction in CD36 transporters. Metformin, but not GW501516, can increase FFA uptake and SCL27A4 expression under mild hypoxia. Described effects might contribute to elevated plasma FFA levels and metabolic derangements in OSA.

The Clinical Impact of Systematic Screening for Obstructive Sleep Apnea in a Type 2 Diabetes Population-Adherence to the Screening-Diagnostic Process and the Acceptance and Adherence to the CPAP Therapy Compared to Regular Sleep Clinic Patients

Obstructive sleep apnea (OSA) is a common disorder in Type 2 diabetes (T2D) patients further increasing their already high cardiovascular risk. As T2D patients typically not report OSA symptoms, systematic screening for OSA in this population is warranted. We aimed to determine the readiness of T2D patients to undergo screening and to compare their adherence to continuous positive airway pressure (CPAP) therapy with "regular" sleep clinic patients who typically seek medical advice on their own initiative. We therefore recruited 494 consecutive T2D patients and offered them OSA screening using home sleep monitoring (type IV device). All participants in high risk of moderate-to-severe OSA were recommended home sleep apnea testing (HSAT) followed by CPAP therapy. Patients were followed-up for 12 months and outcomes compared to 228 consecutive sleep clinic patients undergoing HSAT. Among 307 screened T2D patients, 94 (31%) were identified at high risk of moderate-to-severe OSA. Subsequently, 54 patients underwent HSAT, 51 were recommended, and 38 patients initiated CPAP (acceptance 75%). Among 228 sleep clinic patients, 92 (40%) were recommended and 74 patients initiated CPAP (acceptance 80%). After 1 year, 15 (39%) T2D and 29 (39%) sleep clinic patients showed good CPAP adherence (use ≥ 4 h/night ≥ 70% nights). In conclusion, 20 T2D patients needed to be screened in order to obtain one successfully treated patient. OSA screening in T2D patients identified 31% with moderate-to-severe OSA. Once diagnosed, their CPAP acceptance and adherence did not differ from sleep clinic patients. However, the reasons for the high dropout during the screening-diagnostic process impacting the overall success of the screening program need to be identified and addressed.

Middle cerebral artery anatomical variations and aneurysms: a retrospective study based on computed tomography angiography findings

BACKGROUND

Anatomical variations of the middle cerebral artery (MCA) are an important clinical issue, due to high prevalence of intracranial aneurysms. Anatomical variations of vessels can lead to higher shear stress, which is thought to be the main factor leading to aneurysm formation and consequently to higher prevalence of aneurysms. The aim of this study was to evaluate anatomy of the MCA; to classify MCA aneurysms using computed tomography angiography and to correlate anatomical variations of MCA and circle of Willis with prevalence of MCA aneurysms.

MATERIALS AND METHODS

Two hundred and fifty patients without MCA aneurysms and 100 patients with unruptured MCA aneurysms were qualified for the study, with exclusion of patients after MCA clipping. Four aspects of MCA anatomy were evaluated: division point, its relation to the genu, distance to M1 division and the genu and domination of post-division trunks.

RESULTS

Middle cerebral artery bifurcation was found in 86.2% and trifurcation in 13.8% of the cases. 78.4% of MCAs divided before the genu, 19.2% in the genu and 2.4% after the genu. Upper branch domination was seen in 26%, lower branch in 25.4%, middle branch in 4% and no domination in 44.6% of the cases. In the study group 116 aneurysms were found. 86.2% of the aneurysms were located in M1 division point, 6.9% in M2 segment, 3.4% near lenticulostriatae arteries and 3.4% near early cortical branches. The only anatomical variation, which had significantly higher prevalence in patients with left MCA aneurysms, was domination of upper post-division trunk of MCA. No other statistically significant differences in circle of Willis and MCA variations were found between patients with aneurysms and without them.

CONCLUSIONS

The most common configuration of MCA is bifurcation before the genu with no dominating post-division trunk. Incidence of MCA aneurysms is not correlated with anatomical variations of MCA and the circle of Willis.

An innovative intermittent hypoxia model for cell cultures allowing fast Po2 oscillations with minimal gas consumption

Performing hypoxia-reoxygenation cycles in cell culture with a cycle duration accurately reflecting what occurs in obstructive sleep apnea (OSA) patients is a difficult but crucial technical challenge. Our goal was to develop a novel device to expose multiple cell culture dishes to intermittent hypoxia (IH) cycles relevant to OSA with limited gas consumption. With gas flows as low as 200 ml/min, our combination of plate holders with gas-permeable cultureware generates rapid normoxia-hypoxia cycles. Cycles alternating 1 min at 20% O2 followed by 1 min at 2% O2 resulted in Po2 values ranging from 124 to 44 mmHg. Extending hypoxic and normoxic phases to 10 min allowed Po2 variations from 120 to 25 mmHg. The volume of culture medium or the presence of cells only modestly affected the Po2 variations. In contrast, the nadir of the hypoxia phase increased when measured at different heights above the membrane. We validated the physiological relevance of this model by showing that hypoxia inducible factor-1α expression was significantly increased by IH exposure in human aortic endothelial cells, murine breast carcinoma (4T1) cells as well as in a blood-brain barrier model (2.5-, 1.5-, and 6-fold increases, respectively). In conclusion, we have established a new device to perform rapid intermittent hypoxia cycles in cell cultures, with minimal gas consumption and the possibility to expose several culture dishes simultaneously. This device will allow functional studies of the consequences of IH and deciphering of the molecular biology of IH at the cellular level using oxygen cycles that are clinically relevant to OSA.

Inhibition of Lipolysis Ameliorates Diabetic Phenotype in a Mouse Model of Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is associated with insulin resistance, glucose intolerance, and type 2 diabetes. Causal mechanisms mediating this association are not well defined; however, augmented lipolysis in adipose might be involved. Here, we investigated the effect of acipimox treatment (lipolysis inhibitor) on glucose tolerance and insulin sensitivity in mice exposed to intermittent hypoxia (IH). C57BL6/J mice were exposed for 14 days to IH or control conditions. IH was created by decreasing the fraction of inspired oxygen from 20.9 to 6.5%, 60 times/h. Control exposure was air (fraction of inspired oxygen, 20.9%) delivered at an identical flow rate. Acipimox was provided in drinking water (0.5 g/ml) during exposures. After exposures, intraperitoneal insulin (0.5 IU/kg) and glucose (1 g/kg) tolerance tests were performed, and primary adipocytes were isolated for lipolysis experiments. IH elevated fasting glucose by 51% and worsened glucose tolerance and insulin sensitivity by 33 and 102%, respectively. In parallel, IH increased spontaneous lipolysis by 264%, and reduced epididymal fat mass by 15% and adipocyte size by 8%. Acipimox treatment prevented IH-induced lipolysis and increased epididymal fat mass and adipocyte size by 19 and 10%, respectively. Acipimox fully prevented IH-induced impairments in fasting glycemia, glucose tolerance, and insulin sensitivity. For all reported results, P less than 0.05 was considered significant. Augmented lipolysis contributes to insulin resistance and glucose intolerance observed in mice exposed to IH. Acipimox treatment ameliorated the metabolic consequences of IH and might represent a novel treatment option for patients with obstructive sleep apnea.

Quantitative low-energy ion beam characterization by beam profiling and imaging via scintillation screens

This study presents the imaging and characterization of low-current ion beams in the neutralized state monitored via single crystal YAG:Ce (Y₃Al₅O₁₂) scintillators. To validate the presented beam diagnostic tool, Faraday cup measurements and test etchings were performed. Argon ions with a typical energy of 1.0 keV were emitted from an inductively coupled radio-frequency (13.56 MHz) ion beam source with total currents of some mA. Different beam properties, such as, lateral ion current density, beam divergence angle, and current density in pulsed ion beams have been studied to obtain information about the spatial beam profile and the material removal rate distribution. We observed excellent imaging properties with the scintillation screen and achieved a detailed characterization of the neutralized ion beam. A strong correlation between the scintillator light output, the ion current density, and the material removal rate could be observed.

Screening for obstructive sleep apnea syndrome in patients with type 2 diabetes mellitus: a prospective study on sensitivity of Berlin and STOP-Bang questionnaires

BACKGROUND

Obstructive sleep apnea (OSA) is highly prevalent in patients with Type 2 diabetes mellitus representing an additional risk factor for already increased cardiovascular mortality. As cardiovascular diseases are the main cause of death in this population, there is a need to identify patients with moderate to severe OSA indicated for treatment. We aimed to evaluate the performance of the Berlin, STOP, and STOP-Bang screening questionnaires in a population of patients with Type 2 diabetes mellitus.

METHODS

294 consecutive patients with Type 2 diabetes mellitus filled in the questionnaires and underwent overnight home sleep monitoring using a type IV sleep monitor.

RESULTS

Severe, moderate, and mild OSA was found in 31 (10%), 61 (21%), and 121 (41%) patients, respectively. The questionnaires showed a similar sensitivity and specificity for AHI ≥ 15: 0.69 and 0.50 for Berlin, 0.65 and 0.49 for STOP, and 0.59 and 0.68 for STOP-Bang. However, the performance of the STOP-Bang questionnaire was different in men vs. women, sensitivity being 0.74 vs. 0.29 (p < 0.05) and specificity 0.56 vs. 0.82 (p < 0.05).

CONCLUSIONS

Even the best-performing Berlin questionnaire failed to identify 31% of patients with moderate to severe OSA as being at high risk of OSA, thus preventing them from receiving a correct diagnosis and treatment. Considering that patients with Type 2 diabetes mellitus are at high risk of cardiovascular mortality and also have a high prevalence of moderate to severe OSA, we find screening based on the questionnaires suboptimal and suggest that OSA screening should be performed using home sleep monitoring devices.

Adipogenesis, lipogenesis and lipolysis is stimulated by mild but not severe hypoxia in 3T3-L1 cells

In-vitro investigation of the effects of hypoxia is limited by physical laws of gas diffusion and cellular O2 consumption, making prolonged exposures to stable O2 concentrations impossible. Using a gas-permeable cultureware, chronic effects of mild and severe hypoxia on triglyceride accumulation, lipid droplet size distribution, spontaneous lipolysis and gene expression of adipocyte-specific markers were assessed. 3T3-L1 cells were differentiated under 20%, 4% or 1% O2 using a gas-permeable cultureware. Triglyceride accumulation, expression of genes characteristic for advanced adipocyte differentiation and involvement of key lipogenesis enzymes were assessed after exposures. Lipogenesis increased by 375% under mild hypoxia, but dropped by 43% in severe hypoxia. Mild, but not severe, hypoxia increased formation of large lipid droplets 6.4 fold and strongly induced gene expression of adipocyte-specific markers. Spontaneous lipolysis increased by 488% in mild, but only by 135% in severe hypoxia. Inhibition of ATP-dependent citrate lyase suppressed hypoxia-induced lipogenesis by 81% and 85%. Activation of HIF inhibited lipogenesis by 59%. Mild, but not severe, hypoxia stimulates lipolysis and promotes adipocyte differentiation, probably through excess of acetyl-CoA originating from tricarboxylic acid cycle independently of HIF activation.

Cervical esophageal cancer: a gap in cancer knowledge

BACKGROUND

The aim of this systematic review is to provide an overview of the diagnosis, treatment options and treatment-related complications of cervical esophageal carcinoma (CEC) and to subsequently provide recommendations to improve quality of care.

DESIGN

Studies were identified in PubMed, EMBASE and Web of Science. A total of 107 publications fulfilled the inclusion criteria and were included.

RESULTS

CEC is uncommon, accounting for 2%-10% of all esophageal carcinomas. These tumors are often locally advanced at presentation and have a poor prognosis, with a 5-year overall survival of 30%. Tobacco and alcohol consumption seem to be the major risk factors for developing CEC. Surgery is usually not possible due to the very close relationship to other organs such as the larynx, trachea and thyroid gland. Therefore, the current standard of care is definitive chemoradiation (dCRT) with curative intent. Treatment regimens used to treat CEC are adapted by established regimens in lower esophageal squamous cell carcinoma and head and neck squamous cell carcinoma. However, dCRT may be accompanied by severe side-effects and complications. Several diagnostic and predictive markers have been studied, but currently, there is no other biomarker than clinical stage to determine patient management. Suggestions to improve patient outcomes are to determine the exact radiation dose needed for adequate locoregional control and to combine radiotherapy with optimal systemic therapy backbone.

CONCLUSION

CEC remains unchartered territory for many practising physicians and patients with CEC have a poor prognosis. To improve the outcome for CEC patients, future studies should focus on the identification of new diagnostic biomarkers or targets for radiosensitizers, amelioration of radiation schedules, optimal combination of chemotherapeutic agents and/or new therapeutic targets.

The Effect of Pericellular Oxygen Levels on Proteomic Profile and Lipogenesis in 3T3-L1 Differentiated Preadipocytes Cultured on Gas-Permeable Cultureware

Pericellular oxygen concentration represents an important factor in the regulation of cell functions, including cell differentiation, growth and mitochondrial energy metabolism. Hypoxia in adipose tissue has been associated with altered adipokine secretion profile and suggested as a possible factor in the development of type 2 diabetes. In vitro experiments provide an indispensable tool in metabolic research, however, physical laws of gas diffusion make prolonged exposure of adherent cells to desired pericellular O2 concentrations questionable. The aim of this study was to investigate the direct effect of various O2 levels (1%, 4% and 20% O2) on the proteomic profile and triglyceride accumulation in 3T3-L1 differentiated preadipocytes using gas-permeable cultureware. Following differentiation of cells under desired pericellular O2 concentrations, cell lysates were subjected to two-dimensional gel electrophoresis and protein visualization using Coomassie blue staining. Spots showing differential expression under hypoxia were analyzed using matrix-assisted laser desorption/ionization mass spectrometry. All identified proteins were subjected to pathway analysis. We observed that protein expression of 26 spots was reproducibly affected by 4% and 1% O2 (17 upregulated and 9 downregulated). Pathway analysis showed that mitochondrial energy metabolism and triglyceride synthesis were significantly upregulated by hypoxia. In conclusion, this study demonstrated the direct effects of pericellular O2 levels on adipocyte energy metabolism and triglyceride synthesis, probably mediated through the reversed tricarboxylic acid cycle flux.

Effect of short-term hyperglycemia on adipose tissue fluxes of selected cytokines in vivo during multiple phases of diet-induced weight loss in obese women

CONTEXT

Hyperglycemia is suggested to be one of the drivers of the proinflammatory state observed in obese and diabetic patients.

OBJECTIVES

The objectives of the study was to investigate whether sc abdominal adipose tissue (scAT) could be one of the important sources of proinflammatory cytokines released in response to short-term hyperglycemia and whether this secretion capacity could be influenced by weight loss.

DESIGN, PATIENTS, AND INTERVENTIONS

Output of cytokines and proteins of acute phase from scAT in response to a 3-hours hyperglycemic clamp was evaluated in nine obese women in vivo using Fick's principle. Moreover, the output of cytokines was analyzed during a multiphase dietary intervention consisting of 1 month on a very low-calorie diet and subsequent 5-month weight-stabilization phase.

MAIN OUTCOME MEASURE(S)

The levels of cytokines and proteins of acute phase [IL-6, IL-8, IL-1 receptor antagonist (IL-1Ra), TNF-α, monocyte chemoattractant protein-1 (MCP-1), serum amyloid A, and C-reactive protein] in arterial and venous plasma were measured during each dietary phase. The insulin sensitivity of scAT in respect to the antilipolytic effect of insulin during the clamp was assessed.

RESULTS

Hyperglycemia increased the output of cytokines IL-6, MCP-1, and IL-1Ra from scAT. This effect had a tendency to be reduced after weight loss. The output of other proinflammatory substances from scAT into circulation was not detected. The diet-induced weight loss was associated with the improvement of antilipolytic insulin sensitivity in scAT.

CONCLUSIONS

The results suggest that short-term hyperglycemia induces an increase of the output of cytokines IL-6, IL-1Ra, and MCP-1 from adipose tissue, and this deleterious hyperglycemia effect may be attenuated by the diet-induced weight reduction. This lowered responsiveness of the inflammation-related system may be an important feature of the weight reduction-induced improvement of the metabolic status of obese prediabetic individuals.

The impact of sleep disorders on glucose metabolism: endocrine and molecular mechanisms

Modern lifestyle has profoundly modified human sleep habits. Sleep duration has shortened over recent decades from 8 to 6.5 hours resulting in chronic sleep deprivation. Additionally, irregular sleep, shift work and travelling across time zones lead to disruption of circadian rhythms and asynchrony between the master hypothalamic clock and pacemakers in peripheral tissues. Furthermore, obstructive sleep apnea syndrome (OSA), which affects 4 - 15% of the population, is not only characterized by impaired sleep architecture but also by repetitive hemoglobin desaturations during sleep. Epidemiological studies have identified impaired sleep as an independent risk factor for all cause of-, as well as for cardiovascular, mortality/morbidity. More recently, sleep abnormalities were causally linked to impairments in glucose homeostasis, metabolic syndrome and Type 2 Diabetes Mellitus (T2DM). This review summarized current knowledge on the metabolic alterations associated with the most prevalent sleep disturbances, i.e. short sleep duration, shift work and OSA. We have focused on various endocrine and molecular mechanisms underlying the associations between inadequate sleep quality, quantity and timing with impaired glucose tolerance, insulin resistance and pancreatic β-cell dysfunction. Of these mechanisms, the role of the hypothalamic-pituitary-adrenal axis, circadian pacemakers in peripheral tissues, adipose tissue metabolism, sympathetic nervous system activation, oxidative stress and whole-body inflammation are discussed. Additionally, the impact of intermittent hypoxia and sleep fragmentation (key components of OSA) on intracellular signaling and metabolism in muscle, liver, fat and pancreas are also examined. In summary, this review provides endocrine and molecular explanations for the associations between common sleep disturbances and the pathogenesis of T2DM.

System for exposing cultured cells to intermittent hypoxia utilizing gas permeable cultureware

Tissue intermittent hypoxia (IH) occurs in obstructive sleep apnea, sickle cell anemia, physical exercise and other conditions. Poor gas solubility and slow diffusion through culture media hampers mimicking IH-induced transitions of O(2) in vitro. We aimed to develop a system enabling exposure of cultured cells to IH and to validate such exposure by real-time O(2) measurements and cellular responses. Standard 24-well culture plates and plates with bottoms made from a gas permeable film were placed in a heated cabinet. Desired cycling of O(2) levels was induced using programmable solenoids to purge mixtures of 95% N(2) + 5% CO(2) or 95% O(2) + 5% CO(2). Dissolved oxygen, gas pressure, temperature, and water evaporation were measured during cycling. IH-induced cellular effects were evaluated by hypoxia inducible factor (HIF) and NF-κB luciferase reporters in HEK296 cells and by insulin secretion in rat insulinoma cells. Oxygen cycling in the cabinet was translated into identical changes of O(2) at the well bottom in gas permeable, but not in standard cultureware. Twenty-four hours of IH exposure increased HIF (112%), NF-κB (111%) and insulin secretion (44%). Described system enables reproducible and prolonged IH exposure in cultured cells while controlling for important environmental factors.

The effect of cultureware surfaces on functional and structural components of differentiated 3T3-L1 preadipocytes

Experiments using cultured primary cells or cell lines are a routine in vitro approach used across multiple biological disciplines, However, the structural and functional influences of various cultureware materials on cultured cells is not clearly understood. Surface treatments of cultureware have proven to have profound effects on cell viability and proliferation. In this study, we investigated the impact of polystyrene and fluorocarbon cultureware dishes on the proteomic profile of differentiated 3T3-L1 preadipocytes. After expansion and differentiation of cells on appropriate cultureware dishes, cell lysates were separated using two-dimensional gel electrophoresis and proteins were visualized with Coomassie blue staining. Spots with the highest differential expression between the two culture conditions were subsequently analyzed using matrix-assisted laser desorption/ionization mass spectrometry and the identified proteins were subjected to pathway analysis. We observed that 43% of all spots were differentially expressed depending on the cultureware. Pathway analysis revealed that glucose metabolism, mitochondrial structure and cell differentiation, represented by 14-3-3 protein-mediated signaling and the mitochondrial inner membrane organizing system (MINOS), were significantly affected by cultureware material. These results indicate that cultureware material can have a profound effect on key adipocyte functional pathways. These effects modifications of the cells should be reflected in the design of in vitro experiments and interpretation of their results.

The impact of sleep disorders on glucose metabolism: endocrine and molecular mechanisms

Modern lifestyle has profoundly modified human sleep habits. Sleep duration has shortened over recent decades from 8 to 6.5 hours resulting in chronic sleep deprivation. Additionally, irregular sleep, shift work and travelling across time zones lead to disruption of circadian rhythms and asynchrony between the master hypothalamic clock and pacemakers in peripheral tissues. Furthermore, obstructive sleep apnea syndrome (OSA), which affects 4 - 15% of the population, is not only characterized by impaired sleep architecture but also by repetitive hemoglobin desaturations during sleep. Epidemiological studies have identified impaired sleep as an independent risk factor for all cause of-, as well as for cardiovascular, mortality/morbidity. More recently, sleep abnormalities were causally linked to impairments in glucose homeostasis, metabolic syndrome and Type 2 Diabetes Mellitus (T2DM). This review summarized current knowledge on the metabolic alterations associated with the most prevalent sleep disturbances, i.e. short sleep duration, shift work and OSA. We have focused on various endocrine and molecular mechanisms underlying the associations between inadequate sleep quality, quantity and timing with impaired glucose tolerance, insulin resistance and pancreatic β-cell dysfunction. Of these mechanisms, the role of the hypothalamic-pituitary-adrenal axis, circadian pacemakers in peripheral tissues, adipose tissue metabolism, sympathetic nervous system activation, oxidative stress and whole-body inflammation are discussed. Additionally, the impact of intermittent hypoxia and sleep fragmentation (key components of OSA) on intracellular signaling and metabolism in muscle, liver, fat and pancreas are also examined. In summary, this review provides endocrine and molecular explanations for the associations between common sleep disturbances and the pathogenesis of T2DM.

Intermittent hypoxia impairs glucose homeostasis in C57BL6/J mice: partial improvement with cessation of the exposure

OBJECTIVES

Obstructive sleep apnea is associated with insulin resistance, glucose intolerance, and type 2 diabetes mellitus. Although several studies have suggested that intermittent hypoxia in obstructive sleep apnea may induce abnormalities in glucose homeostasis, it remains to be determined whether these abnormalities improve after discontinuation of the exposure. The objective of this study was to delineate the effects of intermittent hypoxia on glucose homeostasis, beta cell function, and liver glucose metabolism and to investigate whether the impairments improve after the hypoxic exposure is discontinued.

INTERVENTIONS

C57BL6/J mice were exposed to 14 days of intermittent hypoxia, 14 days of intermittent air, or 7 days of intermittent hypoxia followed by 7 days of intermittent air (recovery paradigm). Glucose and insulin tolerance tests were performed to estimate whole-body insulin sensitivity and calculate measures of beta cell function. Oxidative stress in pancreatic tissue and glucose output from isolated hepatocytes were also assessed.

RESULTS

Intermittent hypoxia increased fasting glucose levels and worsened glucose tolerance by 67% and 27%, respectively. Furthermore, intermittent hypoxia exposure was associated with impairments in insulin sensitivity and beta cell function, an increase in liver glycogen, higher hepatocyte glucose output, and an increase in oxidative stress in the pancreas. While fasting glucose levels and hepatic glucose output normalized after discontinuation of the hypoxic exposure, glucose intolerance, insulin resistance, and impairments in beta cell function persisted.

CONCLUSIONS

Intermittent hypoxia induces insulin resistance, impairs beta cell function, enhances hepatocyte glucose output, and increases oxidative stress in the pancreas. Cessation of the hypoxic exposure does not fully reverse the observed changes in glucose metabolism.

Sleep disorders and the development of insulin resistance and obesity

Normal sleep is characterized both by reduced glucose turnover by the brain and other metabolically active tissues, and by changes in glucose tolerance. Sleep duration has decreased over the last several decades; data suggest a link between short sleep duration and type 2 diabetes. Obstructive sleep apnea (OSA) results in intermittent hypoxia and sleep fragmentation, and also is associated with impaired glucose tolerance. Obesity is a major risk factor for OSA, but whether OSA leads to obesity is unclear. The quality and quantity of sleep may profoundly affect obesity and glucose tolerance, and should be routinely assessed by clinicians.

The Impact of Full-Length, Trimeric and Globular Adiponectin on Lipolysis in Subcutaneous and Visceral Adipocytes of Obese and Non-Obese Women

Contribution of individual adiponectin isoforms to lipolysis regulation remains unknown. We investigated the impact of full-length, trimeric and globular adiponectin isoforms on spontaneous lipolysis in subcutaneous abdominal (SCAAT) and visceral adipose tissues (VAT) of obese and non-obese subjects. Furthermore, we explored the role of AMPK (5'-AMP-activated protein kinase) in adiponectin-dependent lipolysis regulation and expression of adiponectin receptors type 1 and 2 (AdipoR1 and AdipoR2) in SCAAT and VAT. Primary adipocytes isolated from SCAAT and VAT of obese and non-obese women were incubated with 20 µg/ml of: A) full-length adiponectin (physiological mixture of all adiponectin isoforms), B) trimeric adiponectin isoform or C) globular adiponectin isoform. Glycerol released into media was used as a marker of lipolysis. While full-length adiponectin inhibited lipolysis by 22% in non-obese SCAAT, globular isoform inhibited lipolysis by 27% in obese SCAAT. No effect of either isoform was detected in non-obese VAT, however trimeric isoform inhibited lipolysis by 21% in obese VAT (all p<0.05). Trimeric isoform induced Thr172 p-AMPK in differentiated preadipocytes from a non-obese donor, while globular isoform induced Ser79 p-ACC by 32% (p<0.05) and Ser565 p-HSL by 52% (p = 0.08) in differentiated preadipocytes from an obese donor. AdipoR2 expression was 17% and 37% higher than AdipoR1 in SCAAT of obese and non-obese groups and by 23% higher in VAT of obese subjects (all p<0.05). In conclusion, the anti-lipolytic effect of adiponectin isoforms is modified with obesity: while full-length adiponectin exerts anti-lipolytic action in non-obese SCAAT, globular and trimeric isoforms show anti-lipolytic activity in obese SCAAT and VAT, respectively.

Quantitative monitoring of WT1 expression in peripheral blood before and after allogeneic stem cell transplantation for acute myeloid leukemia - a useful tool for early detection of minimal residual disease

Overexpressed Wilms tumor gene 1 (WT1) has been found in a majority of patients with acute myeloid leukemia (AML). The aim of this study was to confirm the applicability of WT1 expression measurement as a marker of minimal residual disease (MRD). The expression of WT1 gene was measured by real-time polymerase chain reaction in peripheral blood (PB) according to European Leukemia Net (ELN) recommendations. The WT1 expression was related to the expression of a reference gene Abelson (ABL) and the results were calculated as a number of WT1 copies related to 104 copies of ABL gene. The upper normal limit of WT1 expression was set at 50 copies of WT1 to 104 copies of ABL. Morphological, flow cytometry and chimerism examinations were evaluated according to standard protocols.A total of 51 AML patients with overexpressed WT1 gene were analyzed. The median follow-up after transplantation was 14 (2-72) months. WT1 expression levels exceeding the upper normal limit were considered as a sign of impending hematological relapse, in accord with morphological, flow cytometry and chimerism data, as well as with the expression of the specific fusion genes. Moreover, in 7 patients the rise of WT1 expression preceded all other standard methods. Patients with high WT1 expression before allogeneic hematopoietic stem cell transplantation (allo-HSCT) had significantly worse outcome than patients with low WT1 level. Examination of WT1 expression in PB of patients with AML is a useful tool for MRD monitoring. Moreover, the WT1 gene expression before stem cell transplantation seems to be of prognostic significance.

Change in proportional protein intake in a 10-week energy-restricted low- or high-fat diet, in relation to changes in body size and metabolic factors

OBJECTIVE

To investigate in a secondary analysis of a randomised trial the effects of a low-/high-fat diet and reported change from baseline in energy% from protein (prot%), in relation to changes in body size and metabolic factors.

METHODS

Obese adults (n = 771) were randomised to a 600 kcal energy-deficient low-fat (20-25 fat%) or high-fat (40-45 fat%) diet over 10 weeks. Dietary intake data at baseline and during the intervention were available in 585 completers. We used linear regression to calculate the combined effects of randomised group and groups of prot% change (<-2 /-2 to 2/>2) on outcomes.

RESULTS

The low-fat group with >2 prot% increase lost 1.1 kg more weight (p = 0.03) and reduced cholesterol by 0.25 mmol/l more (p = 0.003) than the high-fat group with >2 prot% decrease. These differences were 2.5-fold and 1.8-fold greater than the differences between the low-fat and high-fat groups while not considering prot% change. The high-fat group reduced plasma triglycerides more than the low-fat group, but not compared to those in the low-fat group with >2 units prot% increase (p fat-protein interaction = 0.01).

CONCLUSIONS

Under energy restriction, participants on a low-fat diet who had increased the percentage energy intake from protein showed the greatest reduction in weight and cholesterol, and a triglyceride reduction equally large to that of participants on a high-fat diet.

Adipose tissue secretion and expression of adipocyte-produced and stromavascular fraction-produced adipokines vary during multiple phases of weight-reducing dietary intervention in obese women

CONTEXT

Obesity is associated with altered plasma levels of adipokines involved in the development of insulin resistance and obesity-related metabolic disturbances.

OBJECTIVE

The aim was to investigate diet-induced changes in adipokine production in sc abdominal adipose tissue (SAT) during a 6-month, multiphase, weight-reducing dietary intervention.

DESIGN, SETTING, PARTICIPANTS, AND INTERVENTIONS

Forty-eight obese women followed a dietary intervention consisting of a very low-calorie diet (VLCD) (1 month), followed by a weight-stabilization (WS) period, which consisted of a low-calorie diet (2 months), and a weight-maintenance diet (3 months).

MAIN OUTCOME MEASURES

Before and at the end of the VLCD and WS, samples of plasma and SAT were obtained. In a subgroup of 26 women, secretion of adipokines was determined in SAT explants, and in a subgroup of 22 women, SAT mRNA expression was measured.

RESULTS

Body weight decreased and insulin sensitivity increased during the intervention. Plasma levels, SAT mRNA expression, and secretion rates of adipocyte-produced adipokines (leptin, serum amyloid A, and haptoglobin) decreased during the VLCD and increased during the WS period. Adipokines produced mainly from stroma-vascular cells (IL-6, IL-8, IL-10, IL-1Ra, TNFα, plasminogen activator inhibitor-1, and monocyte chemoattractant protein-1) increased or remained unchanged during VLCD and decreased to levels equal to or lower than prediet levels during the WS period. The diet-induced changes in homeostasis model assessment of insulin resistance correlated with changes in leptin plasma levels during VLCD, WS, and the entire dietary intervention period.

CONCLUSIONS

Diet-induced regulation of adipokine production in SAT differs according to their cellular origin (adipocytes vs. stroma-vascular cells) and diet phase (VLCD vs. WS). Insulin-sensitivity changes were associated only with those of plasma leptin.

First measurement of chiral dynamics in π- γ → π- π- π+

The COMPASS Collaboration at CERN has investigated the π- γ → π- π- π+ reaction at center-of-momentum energy below five pion masses, sqrt[s]<5m(π), embedded in the Primakoff reaction of 190 GeV pions impinging on a lead target. Exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, t'<0.001  GeV2/c2. Using partial-wave analysis techniques, the scattering intensity of Coulomb production described in terms of chiral dynamics and its dependence on the 3π-invariant mass m(3π)=sqrt[s] were extracted. The absolute cross section was determined in seven bins of sqrt[s] with an overall precision of 20%. At leading order, the result is found to be in good agreement with the prediction of chiral perturbation theory over the whole energy range investigated.

Post-prandial endothelial dysfunction is ameliorated following weight loss in obese premenopausal women

Background

Endothelial dysfunction and postprandial hyperglycemia represent independent risk factors for cardiovascular diseases. Obesity is connected with endothelial impairments; however, it is unclear whether weight loss can modify endothelial function during the postprandial period. The aim of this study was to evaluate endothelial response (post-ischemic forearm blood flow, PIFBF) in a fasted state and following ingestion of 75g glucose before and after very low caloric diet (VLCD).

Material/Methods

40 obese premenopausal women (age 39.6±7.8 years, BMI 34.3±3.2 kg/m²) participated in 4-week very low caloric diet (VLCD, 800kcal/day). Before and after VLCD, the baseline blood flow and PIFBF were measured using a mercury strain gauge plethysmography in fasting state as well as 1 hour after ingestion of 75 g glucose.

Results

Dietary intervention resulted in a 7% weight loss (p<0.05) and a decrease in insulin resistance index HOMA-IR (2.44±1.25 vs. 1.66±0.81, p<0.05). Before VLCD intervention, PIFBF following oral glucose challenge decreased by 8.2±9.1 ml/min/100 g tissue, while after weight loss identical stimulus increased PIFBF by 4.2±8.9 ml/min/100 g tissue (p<0.05). Plasma ICAM-1 and VCAM-1 decreased by 8% and 10%, respectively, throughout the study.

Conclusions

Postprandial endothelial dysfunction is ameliorated following weight loss in obese women. This finding demonstrates the beneficial effects of weight reduction on atherosclerosis risk.

Lipolytic effects of B-type natriuretic peptide 1-32 in adipose tissue of heart failure patients compared with healthy controls

OBJECTIVES

Our goal was to examine the role of B-type natriuretic peptide (BNP) in lipolysis regulation in heart failure (HF) patients.

BACKGROUND

Enhanced adipose tissue lipolysis can contribute to myocardial lipid overload, insulin resistance, and cachexia in advanced HF. Natriuretic peptides were recently recognized to stimulate lipolysis in healthy subjects.

METHODS

Ten nondiabetic HF patients (New York Heart Association functional class III, 50% nonischemic etiology) and 13 healthy subjects (control subjects) of similar age, sex, and body composition underwent a microdialysis study of subcutaneous abdominal adipose tissue. Four microdialysis probes were simultaneously perfused with 0.1 μM BNP(1-32,) 10 μM BNP(1-32), 10 μM norepinephrine (NE) or Ringer's solution. Outgoing dialysate glycerol concentration (DGC) was measured as an index of lipolysis.

RESULTS

Spontaneous lipolysis was higher in HF patients compared with control subjects (DGC: 189 ± 37 μmol/l vs. 152 ± 35 μmol/l, p < 0.01). Response to NE was similar (p = 0.35) in HF patients and control subjects (DGC increase of 1.7 ± 0.2-fold vs. 1.7 ± 0.4-fold). BNP(1-32) 10 μM markedly increased lipolysis in both HF patients and control subjects (DGC increase of 2.8 ± 0.5-fold vs. 3.2 ± 0.3-fold), whereas the response to 0.1 μM BNP(1-32) was more pronounced in HF patients (p = 0.02). In HF patients, spontaneous lipolysis positively correlated with insulin resistance and the response to BNP(1-32) negatively correlated with adiposity.

CONCLUSIONS

BNP(1-32) exerts strong lipolytic effects in humans. Despite marked elevation of plasma immunoreactive BNP, the responsiveness of adipose tissue to BNP(1-32) is not attenuated in HF, possibly reflecting a deficiency of endogenous bioactive BNP. Lipolytic effects of BNP can contribute to excessive fatty acid mobilization in advanced HF.

The spectroscopic studies of humic acid extracted from sediment collected at different seasons

Goczałkowice Reservoir is the biggest water reservoir in the south of Poland. For our studies bottom sediments were collected from eight different places of the reservoir at various seasons of the year. EPR spectroscopy was applied to analyse both quantitatively and qualitatively the humic acids (HA) present in the samples. EPR spectra of the extracted HA exhibited broad lines from the paramagnetic metal ions and narrow lines from free radicals. The values of the free radical concentration obtained for HA amounted to 1.14-13.6 × 1016 spin g(-1) depending on the season and the place of sample collection. The values of the g factor obtained for HA were of the range 2.0027-2.0035. The EPR studies show that HA extracted from bottom sediment collected at various points of the Goczałkowice Reservoir exhibit similar physical-chemical properties. It was also observed that the depth of the reservoir affects the content of the oxygen functional groups as well as the free radical concentration in HA. The identification of the functional groups was done by means of IR. UV/VIS spectroscopy was used to estimate the maturity of the HA.