Short telomeres and high telomerase activity in T-cell prolymphocytic leukemia

To test the role of telomere biology in T-cell prolymphocytic leukemia (T-PLL), a rare aggressive disease characterized by the expansion of a T-cell clone derived from immuno-competent post-thymic T-lymphocytes, we analyzed telomere length and telomerase activity in subsets of peripheral blood leukocytes from 11 newly diagnosed or relapsed patients with sporadic T-PLL. Telomere length values of the leukemic T cells (mean+/-s.d.: 1.53+/-0.65 kb) were all below the 1st percentile of telomere length values observed in T cells from healthy age-matched controls whereas telomere length of normal T- and B cells fell between the 1st and 99th percentile of the normal distribution. Leukemic T cells exhibited high levels of telomerase and were sensitive to the telomerase inhibitor BIBR1532 at doses that showed no effect on normal, unstimulated T cells. Targeting the short telomeres and telomerase activity in T-PLL seems an attractive strategy for the future treatment of this devastating disease.

Cleavage of CXCR1 on neutrophils disables bacterial killing in cystic fibrosis lung disease

Interleukin-8 (IL-8) activates neutrophils via the chemokine receptors CXCR1 and CXCR2. However, the airways of individuals with cystic fibrosis are frequently colonized by bacterial pathogens, despite the presence of large numbers of neutrophils and IL-8. Here we show that IL-8 promotes bacterial killing by neutrophils through CXCR1 but not CXCR2. Unopposed proteolytic activity in the airways of individuals with cystic fibrosis cleaved CXCR1 on neutrophils and disabled their bacterial-killing capacity. These effects were protease concentration-dependent and also occurred to a lesser extent in individuals with chronic obstructive pulmonary disease. Receptor cleavage induced the release of glycosylated CXCR1 fragments that were capable of stimulating IL-8 production in bronchial epithelial cells via Toll-like receptor 2. In vivo inhibition of proteases by inhalation of alpha1-antitrypsin restored CXCR1 expression and improved bacterial killing in individuals with cystic fibrosis. The cleavage of CXCR1, the functional consequences of its cleavage, and the identification of soluble CXCR1 fragments that behave as bioactive components represent a new pathophysiologic mechanism in cystic fibrosis and other chronic lung diseases.

Modulation of human CYP19A1 activity by mutant NADPH P450 oxidoreductase

Mutations in NADPH P450 oxidoreductase (POR) cause a broad spectrum of human disease with abnormalities in steroidogenesis. We have studied the impact of P450 reductase mutations on the activity of CYP19A1. POR supported CYP19A1 activity with a calculated Km of 126 nm for androstenedione and a Vmax of 1.7 pmol/min. Mutations R457H and V492E located in the FAD domain of POR that disrupt electron transfer caused a complete loss of CYP19A1 activity. The A287P mutation of POR decreased the activities of CYP17A1 by 60-80% but had normal CYP19A1 activity. Molecular modeling and protein docking studies suggested that A287P is involved in the interaction of POR:CYP17A1 but not in the POR:CYP19A1 interaction. Mutations C569Y and V608F in the NADPH binding domain of POR had 49 and 28% of activity of CYP19A1 compared with normal reductase and were more sensitive to the amount of NADPH available for supporting CYP19A1 activity. Substitution of NADH for NADPH had a higher impact on C569Y and V608F mutants of POR. Similar effects were obtained at low/high (5.5/8.5) pH, but using octanol to limit the flux of electrons from POR to CYP19A1 inhibited activity supported by all variants. High molar ratios of KCl also reduced the CYP19A1 supporting activities of C569Y and V608F mutants of POR to a greater extent compared to normal POR and A287P mutant. Because POR supports many P450s involved in steroidogenesis, bone formation, and drug metabolism, variations in the effects of POR mutations on specific enzyme activities may explain the broad clinical spectrum of POR deficiency.

Decreased EEG synchronization in Alzheimer's disease and mild cognitive impairment

The hypothesis of a functional disconnection of neuro-cognitive networks in patients with mild cognitive impairment (MCI) and Alzheimer Dementia was investigated using baseline resting EEG data. EEG databases from New York (264 subjects) and Stockholm (155 subjects), including healthy controls and patients with varying degrees of cognitive decline or Alzheimer Dementia were analyzed using Global Field Synchronization (GFS), a novel measure of global EEG synchronization. GFS reflects the global amount of phase-locked activity at a given frequency by a single number; it is independent of the recording reference and of implicit source models. Patients showed decreased GFS values in Alpha, Beta, and Gamma frequency bands, and increased GFS values in the Delta band, confirming the hypothesized disconnection syndrome. The results are discussed within the framework of current knowledge about the functional significance of the affected frequency bands.

Functional imaging of visuospatial processing in Alzheimer's disease

Alzheimer's disease (AD) is known to cause a variety of disturbances of higher visual functions that are closely related to the neuropathological changes. Visual association areas are more affected than primary visual cortex. Additionally, there is evidence from neuropsychological and imaging studies during rest or passive visual stimulation that the occipitotemporal pathway is less affected than the parietal pathway. Our goal was to investigate functional activation patterns during active visuospatial processing in AD patients and the impact of local cerebral atrophy on the strength of functional activation. Fourteen AD patients and fourteen age-matched controls were measured with functional magnetic resonance imaging (fMRI) while they performed an angle discrimination task. Both groups revealed overlapping networks engaged in angle discrimination including the superior parietal lobule (SPL), frontal and occipitotemporal (OTC) cortical regions, primary visual cortex, basal ganglia, and thalamus. The most pronounced differences between the two groups were found in the SPL (more activity in controls) and OTC (more activity in patients). The differences in functional activation between the AD patients and controls were partly explained by the differences in individual SPL atrophy. These results indicate that parietal dysfunction in mild to moderate AD is compensated by recruitment of the ventral visual pathway. We furthermore suggest that local cerebral atrophy should be considered as a covariate in functional imaging studies of neurodegenerative disorders.

Retinol-binding protein 4 is associated with components of the metabolic syndrome, but not with insulin resistance, in men with type 2 diabetes or coronary artery disease

AIMS/HYPOTHESIS: Retinol-binding protein 4 (RBP4) has recently been reported to be associated with insulin resistance and the metabolic syndrome. This study tested the hypothesis that RBP4 is a marker of insulin resistance and the metabolic syndrome in patients with type 2 diabetes or coronary artery disease (CAD) or in non-diabetic control subjects without CAD. METHODS: Serum RBP4 was measured in 365 men (126 with type 2 diabetes, 143 with CAD and 96 control subjects) and correlated with the homeostasis model assessment of insulin resistance index (HOMA-IR), components of the metabolic syndrome and lipoprotein metabolism. RBP4 was detected by ELISA and validated by quantitative Western blotting. RESULTS: RBP4 concentrations detected by ELISA were shown to be strongly associated with the results gained in quantitative Western blots. There were no associations of RBP4 with HOMA-IR or HbA(1c) in any of the groups studied. In patients with type 2 diabetes there were significant positive correlations of RBP4 with total cholesterol, LDL-cholesterol, VLDL-cholesterol, plasma triacylglycerol and hepatic lipase activity. In patients with CAD, there were significant associations of RBP4 with VLDL-cholesterol, plasma triacylglycerol and hepatic lipase activity, while non-diabetic control subjects without CAD showed positive correlations of RBP4 with VLDL-cholesterol and plasma triacylglycerol. CONCLUSIONS/INTERPRETATION: RBP4 does not seem to be a valuable marker for identification of the metabolic syndrome or insulin resistance in male patients with type 2 diabetes or CAD. Independent associations of RBP4 with pro-atherogenic lipoproteins and enzymes of lipoprotein metabolism indicate a possible role of RBP4 in lipid metabolism.

Electroencephalographic changes after pediatric cardiac surgery with cardiopulmonary bypass: is slow wave activity unfavorable?

Pediatric cardiac surgery with cardiopulmonary bypass (CPB) is frequently associated with neurologic deficits. We describe the postoperative EEG changes, assess their possible causes, and evaluate their relevance to neurologic outcome. Thirty-one children and five neonates with congenital heart disease were included. EEG recording started after intubation and continued until 22-96 h after CPB. In addition to conventional analysis, spectral analysis was performed for occipital and frontal electrodes, and differences between pre- and postoperative delta power (delta-deltaP) were calculated. Maximum values of occipital delta-deltaP that occurred within 48 h after CPB were correlated with clinical variables and with perioperative markers of oxidative stress and inflammation. Occipital delta-deltaP correlated with frontal delta-deltaP, and maximum delta-deltaP correlated with conventional rating. Distinct rise of deltaP was detected in 18 of 21 children without any acute or long-term neurologic deficits but only in five of 10 children with temporary or permanent neurologic deficits. Furthermore, maximally registered delta-deltaP was inversely associated with duration of CPB and postoperative ventilation. Maximal delta-deltaP was also inversely associated with the loss of plasma ascorbate (as an index of oxidative stress) and plasma levels of IL-6 and IL-8. Slow wave activity frequently occurs within 48 h after CPB. However, our data do not support the notion that EEG slowing is associated with adverse neurologic outcome. This is supported by the fact that EEG slowing was associated with less oxido-inflammatory stress.

The 14-bp deletion polymorphism in the HLA-G gene displays significant differences between ulcerative colitis and Crohn's disease and is associated with ileocecal resection in Crohn's disease

HLA-G is a non-classical MHC class Ib molecule predominantly expressed in cytotrophoblasts and under pathological conditions also in chronically inflamed and in malignant tissues. Recently an increased expression of HLA-G was found in ulcerative colitis (UC), but not in Crohn's disease (CD). The HLA-G gene is located in IBD3, a linkage region for inflammatory bowel disease (IBD). A 14-bp deletion polymorphism (Del+/Del-) within exon 8 of the HLA-G gene might influence transcription activity and is therefore of potential functional relevance. To investigate whether the 14-bp deletion polymorphism is associated with IBD, 371 patients with CD, 257 patients with UC and 739 controls were genotyped. The heterozygous genotype (P = 0.031) and the Del+ phenotype (P = 0.038) were significantly increased, whereas the homozygous Del- phenotype (P = 0.038) was significantly decreased in UC when compared with CD. Thus, the 14-bp deletion polymorphism within the HLA-G gene displayed significant differences between UC and CD. Moreover, a significant increase of the Del+ allele (P = 0.002) and the Del+/Del+ genotype (P = 0.013) and a consecutive decrease of the Del-/- genotype (P = 0.024) were observed in those CD cases positive for ileocecal resection. Thus, a potential effect of the HLA-G gene in IBD may affect both UC and CD. Other polymorphisms linked to the 14-bp deletion polymorphism might also contribute to immunopathogenesis. As there are several partly functional polymorphisms within the promoter region potentially influencing HLA-G expression, further studies in IBD are necessary in the context of differential expression of HLA-G between UC and CD.

[Periodontitis and cardiovascular disease]

The prevalence of periodontitis and cardiovascular disease (CVD) is high. A mixed infectious biofilm etiology of periodontitis is known but not fully established in CVD. Cofactors; smoking habits, stress, ethnicity, genetics, socioeconomics and age contribute to both diseases. The objectives of this report are to summarize factors in regards to CVD and periodontitis that are clinically relevant. The hypothesis behind a relationship between the two conditions can be founded in (I) shared infections etiology, (II) shared inflammatory response, (III) epidemiological and case-control studies, and (IV) periodontal studies demonstrating improvements of CVD markers. Streptococcus species in the S. mitis group, and S. anginosus group have been identified in periodontitis and are known as pathogens in endocarditis possibly transported from the oral cavity to the heart through bacteremia during dental therapies, and tooth brushing. Other periodontal bacteria such as Porphyromonas gingivalis, Fusobacterium nucleatum and Parvimonas micra are beta-lactamase producing and may contribute to antibiotic resistance (extended spectrum beta-lactamases). Other bacteria in CVD and periodontitis include Staphylococcus aureus, and Pseudomonas aeruginosa. Chlamydia pneumoniae and P. gingivalis lipopolyysaccharide capsels share homology and induce heat-shock protein activity and a cascade of proinflammatory cytokines. Associations between periodontitis and CVD have been presented in many studies when controlling for confounders. Other studies have demonstrated that periodontal therapies increase brachial artery flow rate and reduce serum inflammatory cytokine levels. Thus, physicians caring for subjects at CVD risk should consult with dentists/periodontists. Dentists must improve their medical knowledge and also learn to consult with physicians when treating patients at CVD risk.

Successful lower extremity angioplasty improves brachial artery flow-mediated dilation in patients with peripheral arterial disease

INTRODUCTION: Peripheral arterial disease (PAD) is associated with systemic impaired flow-mediated dilation (FMD) and increased risk for cardiovascular events. Decreased FMD may be caused by a decrease in arterial shear stress due to claudication and inflammation due to muscle ischemia and reperfusion. We assumed that endovascular revascularization of lower limb arterial obstructions ameliorates FMD and lowers inflammation through improvement of peripheral perfusion. METHODS: The study was a prospective, open, randomized, controlled, single-center follow-up evaluation assessing the effect of endovascular revascularization on brachial artery reactivity (FMD) measured by ultrasound, white blood cell (WBC) count, high-sensitive C-reactive protein (hs-CRP), and fibrinogen. We investigated 33 patients (23 men) with chronic and stable PAD (Rutherford 2 to 3) due to femoropopliteal obstruction. Variables were assessed at baseline and after 4 weeks in 17 patients (group A) who underwent endovascular revascularization and best medical treatment, and in 16 patients (group B) who received best medical treatment only. RESULTS: FMD did not differ between group A and B (4.96% +/- 1.86% vs 4.60% +/- 2.95%; P = .87) at baseline. It significantly improved after revascularization in group A (6.44% +/- 2.88%; P = .02) compared with group B at 4 weeks of follow-up (4.53% +/- 3.17%; P = .92), where it remained unchanged. The baseline ankle-brachial index (ABI) was similar for group A and B (0.63 +/- 0.15 vs 0.66 +/- 0.10; P = .36). At 4 weeks of follow-up, ABI was significantly increased in group A (1.05 +/- 0.15; P = .0004) but remained unchanged in group B (0.62 +/- 0.1). WBC counts of the two groups were comparable at baseline (group A: 7.6 +/- 2.26 x 10(6)/mL and group B: 7.8 +/- 2.02 x 10(6)/mL, P = .81). In group A, the leukocyte count significantly decreased after angioplasty from 7.6 +/- 2.26 to 6.89 +/- 1.35 x 10(6)/mL (P = .03). For group B, WBC count did not differ significantly compared with baseline (7.76 +/- 2.64 x 10(6)/mL; P = .94). No effects were observed on hs-CRP or fibrinogen from endovascular therapy. CONCLUSION: Endovascular revascularization with reestablishment of peripheral arterial perfusion improves FMD and reduces WBC count in patients with claudication. Revascularization may therefore have clinical implications beyond relief of symptoms, for example, reducing oxidative stress caused by repeated muscle ischemia or increased shear stress due to improved ambulatory activity.

Cardiovascular risk factors and the metabolic syndrome in pediatric nonalcoholic fatty liver disease

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD), the most common cause of liver disease in children, is associated with obesity and insulin resistance. However, the relationship between NAFLD and cardiovascular risk factors in children is not fully understood. The objective of this study was to determine the association between NAFLD and the presence of metabolic syndrome in overweight and obese children. METHODS AND RESULTS: This case-control study of 150 overweight children with biopsy-proven NAFLD and 150 overweight children without NAFLD compared rates of metabolic syndrome using Adult Treatment Panel III criteria. Cases and controls were well matched in age, sex, and severity of obesity. Children with NAFLD had significantly higher fasting glucose, insulin, total cholesterol, low-density lipoprotein cholesterol, triglycerides, systolic blood pressure, and diastolic blood pressure than overweight and obese children without NAFLD. Subjects with NAFLD also had significantly lower high-density lipoprotein cholesterol than controls. After adjustment for age, sex, race, ethnicity, body mass index, and hyperinsulinemia, children with metabolic syndrome had 5.0 (95% confidence interval, 2.6 to 9.7) times the odds of having NAFLD as overweight and obese children without metabolic syndrome. CONCLUSIONS: NAFLD in overweight and obese children is strongly associated with multiple cardiovascular risk factors. The identification of NAFLD in a child should prompt global counseling to address nutrition, physical activity, and avoidance of smoking to prevent the development of cardiovascular disease and type 2 diabetes.

PU.1 binding to the p53 family of tumor suppressors impairs their transcriptional activity

The transcription factor PU.1 is essential for terminal myeloid differentiation, B- and T-cell development, erythropoiesis and hematopoietic stem cell maintenance. PU.1 functions as oncogene in Friend virus-induced erythroleukemia and as tumor suppressor in acute myeloid leukemias. Moreover, Friend virus-induced erythroleukemia requires maintenance of PU.1 expression and the disruption of p53 function greatly accelerates disease progression. It has been hypothesized that p53-mediated expression of the p21(Cip1) cell cycle inhibitor during differentiation of pre-erythroleukemia cells promotes selection against p53 function. In addition to the blockage of erythroblast differentiation provided by increased levels of PU.1, we propose that PU.1 alters p53 function. We demonstrate that PU.1 reduces the transcriptional activity of the p53 tumor suppressor family and thus inhibits activation of genes important for cell cycle regulation and apoptosis. Inhibition is mediated through binding of PU.1 to the DNA-binding and/or oligomerization domains of p53/p73 proteins. Lastly, knocking down endogenous PU.1 in p53 wild-type REH B-cell precursor leukemia cells leads to increased expression of the p53 target p21(Cip1).

TLR expression on neutrophils at the pulmonary site of infection: TLR1/TLR2-mediated up-regulation of TLR5 expression in cystic fibrosis lung disease

Cystic fibrosis (CF) lung disease is characterized by infection with Pseudomonas aeruginosa and a sustained accumulation of neutrophils. In this study, we analyzed 1) the expression of MyD88-dependent TLRs on circulating and airway neutrophils in P. aeruginosa-infected CF patients, P. aeruginosa-infected non-CF bronchiectasis patients, and noninfected healthy control subjects and 2) studied the regulation of TLR expression and functionality on neutrophils in vitro. TLR2, TLR4, TLR5, and TLR9 expression was increased on airway neutrophils compared with circulating neutrophils in CF and bronchiectasis patients. On airway neutrophils, TLR5 was the only TLR that was significantly higher expressed in CF patients compared with bronchiectasis patients and healthy controls. Studies using confocal microscopy and flow cytometry revealed that TLR5 was stored intracellularly in neutrophils and was mobilized to the cell surface in a protein synthesis-independent manner through protein kinase C activation or after stimulation with TLR ligands and cytokines characteristic of the CF airway microenvironment. The most potent stimulator of TLR5 expression was the bacterial lipoprotein Pam(3)CSK(4). Ab-blocking experiments revealed that the effect of Pam(3)CSK(4) was mediated through cooperation of TLR1 and TLR2 signaling. TLR5 activation enhanced the phagocytic capacity and the respiratory burst activity of neutrophils, which was mediated, at least partially, via a stimulation of IL-8 production and CXCR1 signaling. This study demonstrates a novel mechanism of TLR regulation in neutrophils and suggests a critical role for TLR5 in neutrophil-P. aeruginosa interactions in CF lung disease.

Long-term follow-up of metabolic activity in human alveolar echinococcosis using FDG-PET

AIM: [(18)F]fluoro-deoxyglucose positron-emission-tomography (FDG-PET) detects metabolic activity in alveolar echinococcosis (AE). The slow changes in metabolic and morphological characteristics require long-term follow-up of patients. This is the first study to evaluate metabolic activity over may years, hereby assessing the utility of FDG-PET for the evaluation of disease progression and response to treatment. PATIENTS, METHODS: 15 patients received a follow-up FDG-PET combined with computed tomography (integrated PET/CT) with a median of 6.5 years after the first PET in 1999. Number and location of enhanced metabolic activity in the area of AE lesions was determined. Quantification of intensity of metabolic activity was assessed by calculation of mean standardized uptake values. RESULTS: AE lesions in 11/15 patients had been metabolically inactive initially, but only two showed permanent inactivity over the course of 81 months. Interestingly, in two patients metabolic activity was newly detected after 80 and 82 months. Benzimidazole treatment was intermittently discontinued in seven cases. Persisting activity at FDG-PET demanded continued benzimidazole treatment in four patients. Neither treatment duration, lesional size, calcifications nor regressive changes correlated with metabolic activity. CONCLUSION: Treatment responses are heterogeneous and vary from progressive disease despite treatment to long-term inactive disease with discontinued treatment. Lack of metabolic activity indicates suppressed parasite activity and is not equivalent to parasite death. However, metabolic activity may remain suppressed for years, allowing for temporary treatment discontinuation. Relapses are reliably detected with PET and restarting benzimidazole treatment prevents parasite expansion.

Copper availability contributes to iron perturbations in human nonalcoholic fatty liver disease

BACKGROUND ; AIMS: Iron perturbations are frequently observed in nonalcoholic fatty liver disease (NAFLD). We aimed to investigate a potential association of copper status with disturbances of iron homeostasis in NAFLD. METHODS: We retrospectively studied 140 NAFLD patients and 25 control subjects. Biochemical and hepatic iron and copper parameters were analyzed. Hepatic expression of iron regulatory molecules was investigated in liver biopsy specimens by reverse-transcription polymerase chain reaction and Western blot analysis. RESULTS: NAFLD patients had lower hepatic copper concentrations than control subjects (21.9 +/- 9.8 vs 29.6 +/- 5.1 microg/g; P = .002). NAFLD patients with low serum and liver copper concentrations presented with higher serum ferritin levels (606.7 +/- 265.8 vs 224.2 +/- 176.0 mg/L; P < .001), increased prevalence of siderosis in liver biopsy specimens (36/46 vs 10/47 patients; P < .001), and with elevated hepatic iron concentrations (1184.4 +/- 842.7 vs 319.9 +/- 451.3 microg/g; P = .020). Lower serum concentrations of the copper-dependent ferroxidase ceruloplasmin (21.7 +/- 4.1 vs 30.4 +/- 6.4 mg/dL; P < .001) and decreased liver ferroportin (FP-1; P = .009) messenger RNA expression were found in these patients compared with NAFLD patients with high liver or serum copper concentrations. Accordingly, in rats, a reduced dietary copper intake was paralleled by a decreased hepatic FP-1 protein expression. CONCLUSIONS: A significant proportion of NAFLD patients should be considered copper deficient. Our results indicate that copper status is linked to iron homeostasis in NAFLD, suggesting that low copper bioavailability causes increased hepatic iron stores via decreased FP-1 expression and ceruloplasmin ferroxidase activity thus blocking liver iron export in copper-deficient subjects.