Posttranslational hydroxylation of ankyrin repeats in IkappaB proteins by the hypoxia-inducible factor (HIF) asparaginyl hydroxylase, factor inhibiting HIF (FIH)

Studies on hypoxia-sensitive pathways have revealed a series of Fe(II)-dependent dioxygenases that regulate hypoxia-inducible factor (HIF) by prolyl and asparaginyl hydroxylation. The recognition of these unprecedented signaling processes has led to a search for other substrates of the HIF hydroxylases. Here we show that the human HIF asparaginyl hydroxylase, factor inhibiting HIF (FIH), also efficiently hydroxylates specific asparaginyl (Asn)-residues within proteins of the IkappaB family. After the identification of a series of ankyrin repeat domain (ARD)-containing proteins in a screen for proteins interacting with FIH, the ARDs of p105 (NFKB1) and IkappaBalpha were shown to be efficiently hydroxylated by FIH at specific Asn residues in the hairpin loops linking particular ankyrin repeats. The target Asn residue is highly conserved as part of the ankyrin consensus, and peptides derived from a diverse range of ARD-containing proteins supported FIH enzyme activity. These findings demonstrate that this type of protein hydroxylation is not restricted to HIF and strongly suggest that FIH-dependent ARD hydroxylation is a common occurrence, potentially providing an oxygen-sensitive signal to a diverse range of processes.     

Morphological and functional alterations in ventricular myocytes from male transgenic mice with hypertrophic cardiomyopathy

Familial hypertrophic cardiomyopathy (FHC) is a human genetic disorder caused by mutations in sarcomeric proteins. It is generally characterized by cardiac hypertrophy, fibrosis, and myocyte disarray. A transgenic mouse model of FHC with mutations in the actin-binding domain of the alpha-myosin heavy chain (MyHC) gene displays many phenotypes similar to human FHC. At 4 months, male transgenic (TG) mice present with concentric cardiac hypertrophy that progresses to dilation with age. Accompanying this latter morphological change is systolic and diastolic dysfunction. Left ventricular (LV) myocytes from male TG and wild-type (WT) littermates at 5 and 12 months of age were isolated and used for morphological and functional studies. Myocytes from 5- and 12-month-old TG animals had shorter sarcomere lengths compared with WT. This sarcomere length difference was abolished in the presence of 2,3-butanedione monoxime, suggesting that the basal level of contractile element activation was increased in TG myocytes. Myocytes from 12-month-old TG mice were significantly longer than those from age-matched WT controls, and TG myocytes exhibited Z-band disorganization. When cells were paced at 0.5 Hz, TG myocyte relengthening and the fall in intracellular [Ca2+] were slowed when compared with cells from age-matched WT controls. Moreover, an increased amount of beta-myosin heavy chain protein was found in hearts from TG compared with WT. Thus, myocytes from the alpha-MyHC TG mouse model display many morphological and functional abnormalities that may help explain the LV dysfunction seen in this TG mouse model of FHC.     

Early Myocardial Dysfunction and Benefits of Cardiac Treatment in Young X-Linked Duchenne Muscular Dystrophy Mice

Cardiovascular Drugs and Therapy - Duchenne muscular dystrophy (DMD) is associated with a progressive alteration in cardiac function. The aim of this study was to detect early cardiac dysfunction...     

Autologous stem cell transplantation is safe and effective for fit,older myeloma patients: exploratory results from the Myeloma XI trial

Autologous stem cell transplant (ASCT) remains the standard of care for consolidation after induction therapy for eligible patients with newly diagnosed myeloma. In recent clinical trials comparing ASCT to delayed ASCT, patients aged over 65 were excluded. In real-world practice stem cell transplants are not restricted to those aged under 65 and clinicians decide on transplant eligibility based on a patient’s fitness rather than a strict age cut-off. Data from the UK NCRI Myeloma XI trial, a large phase III randomized controlled trial with pathways for transplant-eligible and -ineligible patients, were used in an exploratory analysis to examine the efficacy and toxicity of ASCT in older patients including an analysis using an age-matched population to compare outcomes for patients receiving similar induction therapy with or without ASCT. Older patients within the transplant-eligible pathway were less likely to undergo stem cell harvest at the end of induction than younger patients and of those patients undergoing ASCT there was a reduction in progression-free survival associated with increasing age. ASCT in older patients was well tolerated with no difference in morbidity or mortality between patients aged <65, 65-69 and 70-75 years. In an age-matched population of patients including those in both the transplant- eligible and -ineligible pathways there was a significant advantage associated with undergoing ASCT with increases in progression-free survival (hazard ratio 0.41, P<0.0001) and overall survival (hazard ratio 0.51, P<0.0001), which persisted even after adjustment for baseline covariates including those related to frailty and response to induction. These findings support the use of ASCT for selected fit, older myeloma patients. EudraCT number, 2009-010956-93     

In vivo imaging of the bronchial wall microstructure using fibered confocal fluorescence microscopy

RATIONALE: Fibered confocal fluorescence microscopy (FCFM) is a new technique that produces microscopic imaging of a living tissue through a 1-mm fiberoptic probe that can be introduced into the working channel of the bronchoscope. OBJECTIVES: To analyze the microscopic autofluorescence structure of normal and pathologic bronchial mucosae using FCFM during bronchoscopy. METHODS: Bronchial FCFM and spectral analyses were performed at 488-nm excitation wavelength on two bronchial specimens ex vivo and in 29 individuals at high risk for lung cancer in vivo. Biopsies of in vivo FCFM-imaged areas were performed using autofluorescence bronchoscopy. RESULTS: Ex vivo and in vivo microscopic and spectral analyses showed that the FCFM signal mainly originates from the elastin component of the basement membrane zone. Five distinct reproducible microscopic patterns were recognized in the normal areas from the trachea down to the more distal respiratory bronchi. In areas of the proximal airways not previously biopsied, one of these patterns was found in 30 of 30 normal epithelia, whereas alterations of the autofluorescence microstructure were observed in 19 of 22 metaplastic or dysplastic samples, five of five carcinomas in situ, and two of two invasive lesions. Disorganization of the fibered network could be found on 9 of 27 preinvasive lesions, compatible with early disruptions of the basement membrane zone. FCFM alterations were also observed in a tracheobronchomegaly syndrome and in a sarcoidosis case. CONCLUSIONS: Endoscopic FCFM represents a minimally invasive method to study specific basement membrane alterations associated with premalignant bronchial lesions in vivo. The technique may also be useful to study the bronchial wall remodeling in nonmalignant chronic bronchial diseases.     

Pharmacodynamics and Pharmacokinetics of Oral Contraceptives Co-administered with Alosetron (Lotronex)

The 5-HT3 receptor antagonist alosetron (Lotronex) is indicated for use in women with severe, chronic, diarrhea-predominant irritable bowel syndrome (IBS) who have failed conventional therapy. Oral contraceptives (OCs) and alosetron are potential co-medications in women of childbearing age. This study assessed the effect of alosetron co-administration on pharmacodynamic markers of contraceptive efficacy, on the pharmacokinetics of estrogen and progesterone OC components, and on the activity of biochemical markers for the risk of thrombosis. This was an open label, nonrandomized two-way crossover study in 18 healthy women stabilized for 3 months on a low-dose OC containing ethinyl estradiol (EE) and levonorgestrel (LN). Alosetron had no effect on serum concentrations of luteinizing hormone (LH) or follicle-stimulating hormone. Ovarian activity grades (assessing follicle size, progesterone, and 17beta-estradiol concentrations) were similar during OC use with and without alosetron. Steady-state (Day 21) AUC24, Cmax, and tmax of both LN and EE were similar during coadministration of alosetron with an OC. Concentrations and activity of biochemical markers of thrombosis risk were not different in the presence of alosetron. These results indicate that alosetron does not alter the pharmacokinetics or pharmacodynamic markers of efficacy for a low-dose combination OC. The results also suggest that thromboembolic risk is not increased when alosetron is co-administered with an OC.     

Insulin receptors in beta-cells are critical for islet compensatory growth response to insulin resistance

Insulin and insulin-like growth factor 1 (IGF1) are ubiquitous growth factors that regulate proliferation in most mammalian tissues including pancreatic islets. To explore the specificity of insulin receptors in compensatory beta-cell growth, we examined two models of insulin resistance. In the first model, we used liver-specific insulin receptor knockout (LIRKO) mice, which exhibit hyperinsulinemia without developing diabetes due to a compensatory increase in beta-cell mass. LIRKO mice, also lacking functional insulin receptors in beta-cells (beta IRKO/LIRKO), exhibited severe glucose intolerance but failed to develop compensatory islet hyperplasia, together leading to early death. In the second model, we examined the relative significance of insulin versus IGF1 receptors in islet growth by feeding high-fat diets to beta IRKO and beta-cell-specific IGF1 receptor knockout (beta IGFRKO) mice. Although both groups on the high-fat diet developed insulin resistance, beta IRKO, but not beta IGFRKO, mice exhibited poor islet growth consistent with insulin-stimulated phosphorylation, nuclear exclusion of FoxO1, and reduced expression of Pdx-1. Together these data provide direct genetic evidence that insulin/FoxO1/Pdx-1 signaling is one pathway that is crucial for islet compensatory growth response to insulin resistance.     

Resistance training in the early postoperative phase reduces hospitalization and leads to muscle hypertrophy in elderly hip surgery patients--a controlled, randomized study

OBJECTIVES: To better understand how immobilization and surgery affect muscle size and function in the elderly and to identify effective training regimes. DESIGN: A prospective randomized, controlled study. SETTING: Bispebjerg University Hospital, Copenhagen, Denmark. PARTICIPANTS: Thirty-six patients (aged 60-86) scheduled for unilateral hip replacement due to primary hip osteoarthrosis. INTERVENTION: Patients were randomized to standard home-based rehabilitation (1 h/d x 12 weeks), unilateral neuromuscular electrical stimulation of the operated side (1 h/d x 12 weeks), or unilateral resistance training of the operated side (3/wk x 12 weeks). MEASUREMENTS: Hospital length of stay (LOS), quadriceps muscle cross-sectional area (CSA), isokinetic muscle strength, and functional performance. Patients were tested presurgery and 5 and 12 weeks postsurgery. RESULTS: Mean+/-standard error LOS was shorter for the resistance training group (10.0+/-2.4 days, P<.05) than for the standard rehabilitation group (16.0+/-7.2 days). Resistance training, but not electrical stimulation or standard rehabilitation, resulted in increased CSA (12%, P<.05) and muscle strength (22-28%, P<.05). Functional muscle performance increased after resistance training (30%, P<.001) and electrical stimulation (15%, P<.05) but not after standard rehabilitation. CONCLUSION: Postoperative resistance training effectively increased maximal muscle strength, muscle mass, and muscle function more than a standard rehabilitation regime. Furthermore, it markedly reduced LOS in elderly postoperative patients.     

WT1 gene expression: useful marker for minimal residual disease in childhood myelodysplastic syndromes and juvenile myelo‐monocytic leukemia?

The WT1 gene is considered to be highly expressed in patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia and chronic myeloid leukemia and is thought to play a key role in maintaining the viability of leukemia cells. However, little is known about the WT1 gene expression levels in pediatric patients with juvenile myelo-monocytic leukemia (JMML) and myelodysplastic syndromes (MDS). We studied WT1 expression in diagnostic bone marrow (BM) and peripheral blood (PB) samples of 90 patients with JMML, low grade MDS, advanced MDS and myelodysplasia-related AML in BM (n = 20) and PB (n = 18) samples of normal healthy volunteer donors.