Protein kinase A inhibition modulates the intracellular routing of gene delivery vehicles in HeLa cells, leading to productive transfection.

J Control Release. 2011 Nov 30;156(1):76-84

Authors: ur Rehman Z, Hoekstra D, Zuhorn IS

Abstract

Cellular entry of nanoparticles for drug- and gene delivery relies on various endocytic pathways, including clathrin- and caveolae-mediated endocytosis. To improve delivery, i.e., the therapeutic and/or cell biological impact, current efforts are aimed at avoiding processing of the carriers along the degradative clathrin-mediated pathway towards lysosomes, and promoting that along the caveolae-mediated pathway. Here, we demonstrate the effective internalization of branched polyethylenimine polymers (BPEI), complexed with nucleic acids, by HeLa cells along both pathways. However, transfection efficiency or nuclear ODN delivery primarily occurs via the caveolae-mediated pathway, along which delivery into lysosomes is avoided. Interestingly, inhibition of intracellular protein kinase A (PKA) activity modulates the intracellular trafficking of both poly- and lipoplexes along the clathrin-mediated pathway by impeding trafficking into the late endosomal/lysosomal compartments, thus avoiding degradation. In case of BPEI polyplexes this promotes their transfection efficiency by 2-3 fold. Evidence excludes early endosomes as a major site for BPEI-mediated release/delivery. Rather, we identify a novel compartment, tentatively characterized as a transferrin(-)/rab9(-)/LAMP1(-) compartment, to which cargo within the clathrin-mediated pathway of endocytosis is rerouted upon inhibition of PKA, and which may act as an alternative and effective site of cargo release in gene delivery. Our findings offer new opportunities for improving gene delivery by non-viral based nanoparticles.

PMID: 21787817 [PubMed - indexed for MEDLINE]

The effect of normothermic recirculation before cold preservation on post-transplant injury of ischemically damaged donor kidneys.

Transpl Int. 2012 Feb;25(2):210-7

Authors: Moers C, van Rijt G, Ploeg RJ, Leuvenink HG

Abstract

Kidneys recovered from donation after cardiac death (DCD) are increasingly used to enlarge the deceased donor pool. Such renal grafts, especially those derived from uncontrolled DCD, have inevitably sustained profound warm ischemic injury, which compromises post-transplant function. Normothermic recirculation (NR) of the deceased donor’s body before organ cooling could be an interesting approach to mitigate the detrimental effect of warm ischemia. To date, however, there is no evidence coming from preclinical studies to support the principle of NR in kidney transplantation. In this study, we subjected 48 Lewis rat kidneys to 15 or 30 min of warm ischemia, and subsequently 0, 1, or 2 h of NR. After 24 h cold storage, kidneys were transplanted into a recipient animal and 24 h later we measured the percentage of cortical necrosis, and determined gene expression of heme oxigenase-1, heat shock protein-70, transforming growth factor-β, kidney injury molecule-1, interleukin-6, hypoxia inducible factor-1α, monocyte chemoattractant protein-1, and α-smooth muscle actin in kidney tissue. We found that NR had no significant influence on any of these markers. Therefore, we conclude that this animal study by no means supports the presumed beneficial effect of NR on kidneys that have been severely damaged by warm ischemia.

PMID: 22077364 [PubMed - indexed for MEDLINE]

Bile acid sequestrants: more than simple resins.

Curr Opin Lipidol. 2012 Feb;23(1):43-55

Authors: Out C, Groen AK, Brufau G

Abstract

PURPOSE OF REVIEW: Bile acid sequestrants (BAS) have been used for more than 50 years in the treatment of hypercholesterolemia. The last decade, bile acids are emerging as integrated regulators of metabolism via induction of various signal transduction pathways. Consequently, BAS treatment may exert unexpected side-effects. We discuss a selection of recently published studies that evaluated BAS in several metabolic diseases.

RECENT FINDINGS: Recently, an increasing body of evidence has shown that BAS in addition to ameliorating hypercholesterolemia are also effective in improving glycemic control in patients with type 2 diabetes, although the mechanism is not completely understood. Furthermore, some reports suggested using these compounds to modulate energy expenditure. Many of these effects have been related to the local effects of BAS in the intestine by directly binding bile acids in the intestine or indirectly by interfering with signaling processes.

SUMMARY: A substantial effort is being made by researchers to fully define the mechanism by which BAS improve glycemic control in type 2 diabetic patients. A new challenge will be to confirm in clinical trials the recent discoveries coming from animal experiments suggesting a role for bile acids in energy metabolism.

PMID: 22186660 [PubMed - indexed for MEDLINE]

Rapid generation of microRNA sponges for microRNA inhibition.

PLoS One. 2012;7(1):e29275

Authors: Kluiver J, Gibcus JH, Hettinga C, Adema A, Richter MK, Halsema N, Slezak-Prochazka I, Ding Y, Kroesen BJ, van den Berg A

Abstract

MicroRNA (miRNA) sponges are transcripts with repeated miRNA antisense sequences that can sequester miRNAs from endogenous targets. MiRNA sponges are valuable tools for miRNA loss-of-function studies both in vitro and in vivo. We developed a fast and flexible method to generate miRNA sponges and tested their efficiency in various assays. Using a single directional ligation reaction we generated sponges with 10 or more miRNA binding sites. Luciferase and AGO2-immuno precipitation (IP) assays confirmed effective binding of the miRNAs to the sponges. Using a GFP competition assay we showed that miR-19 sponges with central mismatches in the miRNA binding sites are efficient miRNA inhibitors while sponges with perfect antisense binding sites are not. Quantification of miRNA sponge levels suggests that this is at least in part due to degradation of the perfect antisense sponge transcripts. Finally, we provide evidence that combined inhibition of miRNAs of the miR-17∼92 cluster results in a more effective growth inhibition as compared to inhibition of individual miRNAs. In conclusion, we describe and validate a method to rapidly generate miRNA sponges for miRNA loss-of-function studies.

PMID: 22238599 [PubMed - indexed for MEDLINE]

Cholesterol-lowering drugs and incident open-angle glaucoma: a population-based cohort study.

PLoS One. 2012;7(1):e29724

Authors: Marcus MW, Müskens RP, Ramdas WD, Wolfs RC, De Jong PT, Vingerling JR, Hofman A, Stricker BH, Jansonius NM

Abstract

BACKGROUND: Open-angle glaucoma (OAG) is a progressive neurodegenerative disease that may lead to blindness. An elevated intraocular pressure (IOP) is its major risk factor. OAG treatment is currently exclusively directed towards the lowering of the IOP. IOP lowering does not prevent disease progression in all patients and thus other treatment modalities are needed. Earlier studies reported cholesterol-lowering drugs to have neuroprotective properties. The aim of this study was to determine the associations between the use of cholesterol-lowering drugs and incident OAG.

METHODOLOGY/PRINCIPAL FINDINGS: Participants in a prospective population-based cohort study underwent ophthalmic examinations, including IOP measurements and perimetry, at baseline and follow-up. The use of statins and non-statin cholesterol-lowering drugs was monitored continuously during the study. Associations between the use of cholesterol-lowering drugs and incident OAG were analyzed with Cox regression; associations between cholesterol-lowering drugs and IOP at follow-up were analyzed with multiple linear regression. During a mean follow-up of 9.8 years, 108 of 3939 eligible participants (2.7%) developed OAG. The hazard ratio for statin use was 0.54 (95% confidence interval 0.31-0.96; P = 0.034) and for non-statin cholesterol-lowering drugs 2.07 (0.81-5.33; P = 0.13). The effect of statins was more pronounced with prolonged use (hazard ratio 0.89 [0.41-1.94; P = 0.77] for use two years or less; 0.46 [0.23-0.94; P = 0.033] for use more than two years; P-value for trend 0.10). The analyzes were adjusted for age and gender, baseline IOP and IOP-lowering treatment, the family history of glaucoma, and myopia. There was no effect of statins on the IOP.

CONCLUSIONS/SIGNIFICANCE: Long-term use of statins appears to be associated with a reduced risk of OAG. The observed effect was independent of the IOP. These findings are in line with the idea that statins have neuroprotective properties and may open a way to a new OAG treatment modality.

PMID: 22238644 [PubMed - indexed for MEDLINE]

The cardiovascular risk profile of atherosclerotic gastrointestinal ischemia is different from other vascular beds.

Am J Med. 2012 Apr;125(4):394-8

Authors: Veenstra RP, ter Steege RW, Geelkerken RH, Huisman AB, Kolkman JJ

Abstract

BACKGROUND: The distribution of cardiovascular risk factors in patients with chronic gastrointestinal ischemia due to atherosclerosis of the splanchnic vessels (chronic splanchnic syndrome) is not well studied. The aim of this study was to determine the cardiovascular risk factor pattern in patients with chronic splanchnic syndrome.

METHODS: From April 2003 to September 2007, atherosclerotic risk factors in consecutive patients with chronic splanchnic syndrome were compared prospectively with the general atherosclerotic risk profile in Western Europe and worldwide risk profile of coronary heart disease, peripheral artery disease, and cerebral vascular disease.

RESULTS: Of 376 analyzed patients, 97 were diagnosed with chronic splanchnic syndrome. Data from 90 patients were available for analysis (7 were excluded because of incomplete data). Mean age was 63 years (range 28-86 years), and 74% were female. Fifty-nine percent of the patients had atherosclerotic disease in other vascular beds. Smoking was reported in 57%, and increased bodyweight in 21%. Hypercholesterolemia was present in 53%, hypertension in 62%, and diabetes in 21%.

CONCLUSIONS: The atherosclerotic risk profile in patients with chronic splanchnic syndrome differed from other atherosclerotic diseases with a female preponderance, lower incidence of obesity/increased bodyweight, diabetes, hypertension, and hypercholesterolemia. Reduced caloric intake, related to the postprandial pain, may explain the observed differences.

PMID: 22305578 [PubMed - indexed for MEDLINE]

Maxillary Overdentures Supported by Anteriorly or Posteriorly Placed Implants Opposed by a Natural Dentition in the Mandible: A 1-Year Prospective Case Series Study.

Clin Implant Dent Relat Res. 2012 May 11;

Authors: Slot W, Raghoebar GM, Vissink A, Meijer HJ

Abstract

Background: For maxillary overdenture therapy, treatment guidelines are missing. There is a need for longitudinal studies. Purpose: The purpose of this 1-year prospective case series study was to assess the treatment outcome of maxillary overdentures supported by six dental implants opposed by natural antagonistic teeth in the mandible. Materials and Methods: Fifty patients were treated with a maxillary overdenture supported by six dental implants, either placed in the anterior region (n = 25 patients) or in the posterior region (n = 25 patients). Items of evaluation were the following: survival of implants, condition of hard and soft peri-implant tissues, and patients’ satisfaction. Results: One-year implant survival rate was 98% in the anterior group and 99.3% in the posterior group. Mean radiographic bone loss in the anterior and posterior groups after 1 year of loading was 0.22 and 0.50 mm, respectively. Mean scores for plaque, calculus, gingiva, bleeding, and pocket probing depth were low, and patients’ satisfaction was high, with no differences between the groups. Conclusion: Six dental implants placed in either the anterior region or the posterior region of the edentulous maxilla, connected with a bar, and opposed by antagonistic teeth in the mandible supply a proper base for the support of an overdenture.

PMID: 22577941 [PubMed - as supplied by publisher]

Impact of Platform Switching on Peri-Implant Bone Remodeling around Short Implants in the Posterior Region, 1-Year Results from a Split-Mouth Clinical Trial.

Clin Implant Dent Relat Res. 2012 May 11;

Authors: Telleman G, Raghoebar GM, Vissink A, Meijer HJ

Abstract

Aim: To assess the effect of platform switching on peri-implant bone remodeling around short implants (8.5 mm) placed in the resorbed posterior mandibular and maxillary region of partially edentulous patients. Materials and Methods: Seventeen patients with one or more missing teeth at both sides in the posterior region were, according to a split-mouth design, randomly assigned to be treated with a platform-matched (control) implant on the one side and a platform-switched implant (test) on the other side. A total of 62 short implants (8.5 mm) with a dual-acid etched surface with nanometer-sized calcium phosphate particles was placed. Follow-up visits were conducted one month and one year after placing the implant crown. Outcome measures were interproximal bone level changes, implant survival and clinical parameters. Results: One year after loading, peri-implant bone remodeling around test implants (0.53 ± 0.54 mm) was significant less than around control implants (0.85 ± 0.65 mm; p = .003). With regard to implant survival and clinical parameters no significant differences were observed between test and control implants. Conclusions: This study suggested that peri-implant bone remodeling is affected by platform switching. One year after loading, interproximal bone levels were better maintained at implants restored according to the platform switching concept.

PMID: 22577959 [PubMed - as supplied by publisher]

Cost-Effectiveness of Hypothermic Machine Preservation Versus Static Cold Storage in Renal Transplantation.

Am J Transplant. 2012 May 11;

Authors: Groen H, Moers C, Smits JM, Treckmann J, Monbaliu D, Rahmel A, Paul A, Pirenne J, Ploeg RJ, Buskens E

Abstract

Static cold storage (CS) is the most widely used organ preservation method for deceased donor kidney grafts but there is increasing evidence that hypothermic machine perfusion (MP) may result in better outcome after transplantation. We performed an economic evaluation of MP versus CS alongside a multicenter RCT investigating short- and long-term cost-effectiveness. Three hundred thirty-six consecutive kidney pairs were included, one of which was assigned to MP and one to CS. The economic evaluation combined the short-term results based on the empirical data from the study with a Markov model with a 10-year time horizon. Direct medical costs of hospital stay, dialysis treatment, and complications were included. Data regarding long-term survival, quality of life, and long-term costs were derived from literature. The short-term evaluation showed that MP reduced the risk of delayed graft function and graft failure at lower costs than CS. The Markov model revealed cost savings of $86 750 per life-year gained in favor of MP. The corresponding incremental cost-utility ratio was minus $496 223 per quality-adjusted life-year (QALY) gained. We conclude that life-years and QALYs can be gained while reducing costs at the same time, when kidneys are preserved by MP instead of CS.

PMID: 22578189 [PubMed - as supplied by publisher]

Measurement Properties of the Groningen Frailty Indicator in Home-Dwelling and Institutionalized Elderly People.

J Am Med Dir Assoc. 2012 May 12;

Authors: Peters LL, Boter H, Buskens E, Slaets JP

Abstract

OBJECTIVES: To enable prevention of poor outcome in elderly people, a valid instrument is required to detect individuals at high risk. The concept of frailty is a better predictor than age alone. The Groningen Frailty Indicator (GFI) has been developed to identify frailty. We assessed feasibility, reliability, and construct validity of the self-assessment version of the GFI. DESIGN: Cross-sectional. SETTING: Community-based. PARTICIPANTS: Home-dwelling and institutionalized elderly persons were included in the study (n = 353) who met the following inclusion criteria: persons 65 years and older who were able to fill out questionnaires. MEASUREMENTS: The feasibility of the GFI was assessed by determining the proportion of missing values per item. The internal consistency reliability of the GFI was established by calculating the KR-20. Mann-Whitney and Kruskal-Wallis tests were applied to assess discrimination between specific subgroups (known group validity). Convergent and discriminant validity was assessed using Spearman Rank correlations between GFI and diseases and disorders, case complexity, and health care needs (INTERMED), life satisfaction (Cantril Ladder of Life), activities of daily living (Katz), quality of life (EQ-5D), and mental health (SF-36). Finally, we used multivariate regression analyses to evaluate the cutoff score of the GFI (<4 versus ≥4). RESULTS: A total of 296 (84%) of the participants completed all items of the GFI; the internal consistency was 0.68. The GFI yielded statistically significant GFI scores for subgroups (known group validity). The correlations for the convergent (range 0.45 to 0.61) and discriminant validity (range 0.08 to 0.50) were also as hypothesized. In contrast with nonfrail participants, frail older persons had higher levels of case complexity, disability, and lower quality of life and life satisfaction. CONCLUSIONS: This study supports the feasibility, reliability, and validity of the self-assessment version of the GFI in home-dwelling and institutionalized elderly people.

PMID: 22579590 [PubMed - as supplied by publisher]

Proliferating bloodstream-form Trypanosoma brucei use a negligible part of consumed glucose for anabolic processes.

Int J Parasitol. 2012 May 8;

Authors: Haanstra JR, van Tuijl A, van Dam J, van Winden W, Tielens AG, van Hellemond JJ, Bakker BM

Abstract

Our quantitative knowledge of carbon fluxes in the long slender bloodstream form (BSF) Trypanosoma brucei is mainly based on non-proliferating parasites, isolated from laboratory animals and kept in buffers. In this paper we present a carbon balance for exponentially growing bloodstream form trypanosomes. The cells grew with a doubling time of 5.3 h, contained 46 μmol of carbon (10(8) cells)(-1) and had a glucose consumption flux of 160 nmol min(-1) (10(8) cells)(-1). The molar ratio of pyruvate excreted versus glucose consumed was 2.1. Furthermore, analysis of the (13)C label distribution in pyruvate in (13)C-glucose incubations of exponentially growing trypanosomes showed that glucose was the sole substrate for pyruvate production. We conclude that the glucose metabolised in glycolysis was hardly, if at all, used for biosynthetic processes. Carbon flux through glycolysis in exponentially growing trypanosomes was 10 times higher than the incorporation of carbon into biomass. This biosynthetic carbon is derived from other precursors present in the nutrient rich growth medium. Furthermore, we found that the glycolytic flux was unaltered when the culture went into stationary phase, suggesting that most of the ATP produced in glycolysis is used for processes other than growth.

PMID: 22580731 [PubMed - as supplied by publisher]

From genome-wide association studies to disease mechanisms: celiac disease as a model for autoimmune diseases.

Semin Immunopathol. 2012 May 14;

Authors: Kumar V, Wijmenga C, Withoff S

Abstract

Celiac disease is characterized by a chronic inflammatory reaction in the intestine and is triggered by gluten, a constituent derived from grains which is present in the common daily diet in the Western world. Despite decades of research, the mechanisms behind celiac disease etiology are still not fully understood, although it is clear that both genetic and environmental factors are involved. To improve the understanding of the disease, the genetic component has been extensively studied by genome-wide association studies. These have uncovered a wealth of information that still needs further investigation to clarify its importance. In this review, we summarize and discuss the results of the genetic studies in celiac disease, focusing on the “non-HLA” genes. We also present novel approaches to identifying the causal variants in complex susceptibility loci and disease mechanisms.

PMID: 22580835 [PubMed - as supplied by publisher]

SYMPTOM PROFILES OF DSM-IV-DEFINED REMISSION, RECOVERY, RELAPSE, AND RECURRENCE OF DEPRESSION: THE ROLE OF THE CORE SYMPTOMS.

Depress Anxiety. 2012 May 11;

Authors: Conradi HJ, Ormel J, de Jonge P

Abstract

BACKGROUND: Depression outcomes in research and clinical practice are commonly defined by the concepts of remission, recovery, relapse, and recurrence. Despite their widespread use, there has been little empirical examination of these concepts. Therefore, we investigated profiles of individual symptoms during each of these phases of depression. METHODS: In a 3-year prospective study of 267 depressed primary care patients, we established the presence or absence of the individual DSM-IV depressive symptoms week-by-week during DSM-IV-defined remissions, recoveries, relapses, and recurrences. We measured symptoms in 12 quarterly assessments using the Composite International Diagnostic Interview. RESULTS: Remissions were characterized by double the proportion of time that the core symptoms were present compared to the initial phase of recoveries after a major depressive episode (MDE; 59 versus 32%; Z = -3.03; P = .002). Before a relapse, remissions again showed elevated levels of core symptoms in comparison to the final phase of recoveries before a recurrence (58 versus 26%; Z = -2.99; P = .003). CONCLUSIONS: Compared with the initial and final phases of recoveries, remissions showed a consistently higher level of core symptoms. Clinically, this means that unresolved core symptoms in the direct aftermath of a MDE seem to constitute a risk for relapse and should be the target of preventive or augmented interventions.

PMID: 22581500 [PubMed - as supplied by publisher]

Revealing causal heterogeneity using time series analysis of ambulatory assessments: application to the association between depression and physical activity after myocardial infarction.

Psychosom Med. 2012 May;74(4):377-86

Authors: Rosmalen JG, Wenting AM, Roest AM, de Jonge P, Bos EH

Abstract

Objective Studies in psychosomatic medicine are characterized by analyses that typically compare groups. This nomothetic approach leads to conclusions that apply to the average group member but not necessarily to individual patients. Idiographic studies start at the individual patient and are suitable to study associations that differ between time points or between individuals. We illustrate the advantages of the idiographic approach in analyzing ambulatory assessments, taking the association between depression and physical activity after myocardial infarction as an example. Methods Five middle-aged men who had myocardial infarction with mild to moderate symptoms of depression were included in this study. Four of these participants monitored their physical activity and depressive symptoms during a period of 2 to 3 months using a daily self-registration form. The time series of each individual participant were investigated using vector autoregressive modeling, which enables the analysis of temporal dynamics between physical activity and depression. Results We found causal heterogeneity in the association between depression and physical activity. Participants differed in the predominant direction of effect, which was either from physical activity to depression (n = 1, 85 observations, unstandardized effect size = -0.183, p = .03) or from depression to physical activity (n = 2, 65 and 59 observations, unstandardized effect sizes = -0.038 and -0.381, p < .001 and p = .04). Also, the persistency of effects differed among individuals. Conclusions Vector autoregressive models are suitable in revealing causal heterogeneity and can be easily used to analyze ambulatory assessments. We suggest that these models might bridge the gap between science and clinical practice by translating epidemiological results to individual patients.

PMID: 22582335 [PubMed - in process]

Exploring the metabolic state of microorganisms using metabolomics.

Bioanalysis. 2011 Nov;3(21):2443-58

Authors: Merlo ME, Jankevics A, Takano E, Breitling R

Abstract

…

Low-pressure valves in hydrocephalic children: a retrospective analysis.

Childs Nerv Syst. 2012 Mar;28(3):469-73

Authors: Breimer GE, Sival DA, Hoving EW

Abstract

…

Love is more than just a kiss: a neurobiological perspective on love and affection.

Neuroscience. 2012 Jan 10;201:114-24

Authors: de Boer A, van Buel EM, Ter Horst GJ
…

Evaluating joint destruction in rheumatoid arthritis: is it necessary to radiograph both hands and feet?

Ann Rheum Dis. 2012 May 12;

Authors: Knevel R, Kwok K, de Rooy D, Posthumus…

Long working hours are associated with incident depressive and anxiety symptoms in women.

Evid Based Ment Health. 2012 May 11;

Authors: Bültmann U

PMID: 22581019 [PubMed -…

Suzanne null Arends, Anneke null Spoorenberg, Pieternella M Houtman, Martha K Leijsma, Reinhard null Bos, Cees GM Kallenberg, Henk null Groen, Elisabeth null Brouwer, Eveline null van der Veer
Arthritis Research & Therapy 2012, 14:R98 (30 April 2012)