NAT1 genotypes do not predict response to mesalamine in patients with ulcerative colitis

BACKGROUND: 5- Aminosalicylic acid (5-ASA) is metabolised in colonic mucosa by N-acetyltransferase 1 (NAT1). Common genetic polymorphisms in this enzyme result in rapid or slow acetylation. 5-ASA treatment causes side effects in up to 10 % of patients with ulcerative colitis (UC). We therefore determined genetic variations of NAT1 in patients with UC and looked for a possible association with the clinical response to 5-ASA. METHODS: DNA was obtained from 78 patients with UC. 77 % of the patients were in remission during 5-ASA treatment, whereas 23 % suffered from active disease. NAT1 genotyping was performed for 23 known alleles using RFLP and sequence analysis. Clinical response to 5-ASA was determined by medical record review and associated with NAT1 genotypes. RESULTS: Utilising PCR we amplified a 570-bp coding region of the human NAT1 gene in addition to 240 bp in the 3'-untranslated region (UTR). 4 NAT1 alleles previously known as NAT1*3, *4, *10 and *11 were recovered. 31 % of the patients were heterozygous and 4 % homozygous for the NAT1*10 allele. 6 % were heterozygous for the NAT1*3 allele. 6 % were heterozygous for the NAT1*11 allele. No association was found between NAT1 genotype and clinical response as well as side effects to 5-ASA in patients with UC. CONCLUSIONS: NAT1 genotypes do not predict response or side effects to mesalamine in patients with UC. Variations caused by non-genomic effects may be associated with the clinical response to 5-ASA.     

Genetic variation within the ANGPTL4 gene is not associated with metabolic traits in white subjects at an increased risk for type 2 diabetes mellitus

Angiopoietin-like protein 4 (ANGPTL4) represents an adipokine with metabolic effects within adipose tissue, such as inhibition of lipoprotein lipase activity and stimulation of lipolysis. These effects were convincingly demonstrated in mice. Therefore, we asked whether genetic variation within the ANGPTL4 gene contributes to prediabetic phenotypes, such as dyslipidemia, insulin resistance, or beta-cell dysfunction, in white subjects at an increased risk for type 2 diabetes mellitus. We genotyped 629 subjects with and without a family history of diabetes for the 4 single nucleotide polymorphisms (SNPs) rs4076317, rs2278236, rs1044250, and rs11672433 and performed correlational analyses with metabolic traits. For metabolic characterization, all subjects underwent an oral glucose tolerance test; a subset was additionally characterized by hyperinsulinemic-euglycemic clamp. The 4 SNPs rs4076317, rs2278236, rs1044250, and rs11672433 cover 100% of common genetic variation (minor allele frequency>or=0.05) within the ANGPTL4 gene (r2>or=0.8). None of these SNPs revealed significant correlation with anthropometric data (sex, age, body mass index, body fat, and waist-hip ratio) or with family history of diabetes. Furthermore, no reliable correlations were found with fasting triglycerides, fasting nonesterified fatty acids, and area under the curve of nonesterified fatty acids during oral glucose tolerance test or with parameters of insulin sensitivity and insulin secretion. Finally, haplotype analysis revealed the existence of 8 common diplotypes. None of these, however, was significantly correlated with insulin sensitivity, insulin secretion, or plasma lipid measures. We conclude that common genetic variation within the ANGPTL4 gene may not play a major role in the development of prediabetic phenotypes in our white population.     

Targeting of heat shock protein 32 (Hsp32)/heme oxygenase-1 (HO-1) in leukemic cells in chronic myeloid leukemia: a novel approach to overcome resistance against imatinib

Resistance toward imatinib and other BCR/ABL tyrosine kinase inhibitors remains an increasing clinical problem in the treatment of advanced stages of chronic myeloid leukemia (CML). We recently have identified the heat shock protein 32 (Hsp32)/heme oxygenase-1 (HO-1) as a BCR/ABL-dependent survival molecule in CML cells. We here show that silencing Hsp32/HO-1 in CML cells by an siRNA approach results in induction of apoptosis. Moreover, targeting Hsp32/HO-1 by either pegylated zinc protoporphyrine (PEG-ZnPP) or styrene maleic acid-micelle-encapsulated ZnPP (SMA-ZnPP) resulted in growth inhibition of BCR/ABL-transformed cells. The effects of PEG-ZnPP and SMA-ZnPP were demonstrable in Ba/F3 cells carrying various imatinib-resistant mutants of BCR/ABL, including the T315I mutant, which exhibits resistance against all clinically available BCR/ABL tyrosine kinase inhibitors. Growth-inhibitory effects of PEG-ZnPP and SMA-ZnPP also were observed in the CML-derived human cell lines K562 and KU812 as well as in primary leukemic cells obtained from patients with freshly diagnosed CML or imatinib-resistant CML. Finally, Hsp32/HO-1-targeting compounds were found to synergize with either imatinib or nilotinib in producing growth inhibition in imatinib-resistant K562 cells and in Ba/F3 cells harboring the T315I mutant of BCR/ABL. In summary, these data show that HO-1 is a promising novel target in imatinib-resistant CML.     

Arthritogenic antibodies specific for a major type II collagen triple-helical epitope bind and destabilize cartilage independent of inflammation

OBJECTIVE: To investigate the significance and pathogenic potential of a highly conserved major type II collagen triple-helical epitope-specific antibody (U1; amino acids 494-504) in vivo and in vitro in patients with early rheumatoid arthritis (RA) and in experimental animal models of collagen-induced arthritis (CIA). METHODS: U1-specific antibodies in sera from patients with early RA (with or without joint erosions) were analyzed. Disease progression in the CIA models in mice and rats with anti-U1 antibodies was compared. The pathogenicity of binding of monoclonal antibodies (mAb) UL1 and CIIF4 to the U1 epitope and the F4 epitope (aa 926-936), respectively, was compared in vivo and on chondrocyte cultures and preformed cartilage in vitro, using Fourier transform infrared microspectroscopy analysis. In addition, UL1-induced proteoglycan depletion in vivo in the presence and absence of the complement factor C5 was analyzed. RESULTS: Increased levels of U1 antibodies were observed in patients with early RA, especially in association with joint erosions. A significant correlation of U1-specific antibodies with disease progression was found in rats and mice with CIA. UL1 mAb induced, whereas CIIF4 mAb inhibited, the progression of arthritis. Similarly, UL1, but not CIIF4, impaired matrix synthesis on chondrocyte cultures and adversely affected preformed cartilage. Furthermore, UL1 induced significant proteoglycan depletion in vivo 3 days after injection, even in the absence of C5. CONCLUSION: Antibody epitope specificity contributes significantly to the development of arthritis, and the early pathogenic events operate independent of inflammation both in vitro and in vivo.     

Platelets in regenerative medicine

Stem and progenitor cells have evolved as the central cell type in regenerative medicine. This focussed approach may, however, sometimes narrow the point of view. Recently, platelets have been shown to strongly influence progenitor cell biology and to serve as regenerative cells themselves. Platelets represent an important recruitment factor for circulating progenitor cells. Furthermore, they modulate progenitor cell chemotaxis, migration and differentiation. Platelets are crucial for the regeneration of parenchymatous organs such as the liver. Moreover, in the clinical setting, platelets are already applied for the restoration of connective and bone tissue. However, also adverse effects can be mediated by platelets and progenitor cells exposed to platelets, including the induction of pro-inflammatory processes. This review gives an update on platelets as regenerative cells and as modulators of progenitor cell biology in (patho-) physiological conditions. Abundant data obtained during the last decade have linked progenitor and stem cells to tissue repair. Very recent accumulating results from different groups revealed that platelets may have a strong influence on central functions of these progenitor cells. Only little is known about the impact of platelets themselves on tissue regeneration. Therefore, this review highlights the role of platelets themselves as a potential effector cell for tissue regeneration and their impact on progenitor cell biology.     

Tackling frontal lobe–related functions in PKU through functional brain imaging: a Stroop task in adult patients

Background  

Profound mental retardation in phenylketonuria (PKU) can be prevented by a low phenylalanine (Phe) diet. However, even patients treated early have inconsistently shown deficits in several frontal lobe–related neuropsychological tasks such as the widely accepted Stroop task. The goal of this study was to investigate whether adult patients exhibit altered brain activation in Stroop-related locations in comparison to healthy controls and if an acute increase in blood Phe levels in patients has an effect on activation patterns.     

Effects of growth hormone replacement within the KIMS survey on estimated cardiovascular risk and predictors of risk reduction in patients with growth hormone deficiency

Objective There is growing evidence for an increased cardiovascular (CV) risk in untreated growth hormone deficiency of adults (GHD). We aimed at estimating CV risk with established algorithms before and during GH replacement in GHD and in healthy controls and at identifying predictors of risk reduction. Design A prospective, nested case‐control study. Patients We included 344 patients (44·7 ± 14·9 years) from the German Pfizer (formerly Kabi) International Metabolic Database (KIMS) cohort and included a healthy sex‐ and age‐matched control group from a primary care cohort. Measurements We calculated Framingham, Prospective Cardiovascular Münster Heart Study (PROCAM) and European Society of Cardiology (ESC) Score algorithms at all time points. In multivariate analyses, we analysed potential predictors of 2‐year reduction in CV risk, defined as a higher than median reduction in risk. Results In KIMS, the estimated 10‐year risks of CV events or CV mortality calculated with Framingham, PROCAM and ESC Score algorithms at baseline were 4·6%, 6·0% and 2·3%, respectively. These dropped to 2·4%, 4·8% and 0·8%, respectively, after 2 years of GH replacement (all P < 0·001 vs baseline) and returned to baseline levels after four years of GH replacement. In controls, the Framingham risk estimates were lower than in KIMS at baseline. All risk estimates increased during follow‐up and were significantly higher than in KIMS after four years (all P < 0·01). In backward‐selection models, high total cholesterol, low high‐density lipoprotein (HDL) cholesterol and male sex were significant predictors of response in most scores. Conclusion Two years of GH replacement decreased CV risk estimates approximately by half. Male sex, high total and low HDL cholesterol levels are potential predictors of good response.     

Embolic events in patients with atrial fibrillation and effective anticoagulation: value of transesophageal echocardiography to guide direct-current cardioversion. Final results of the Ludwigshafen Observational Cardioversion Study

OBJECTIVES: The primary objective was to evaluate the usefulness of transesophageal echocardiography (TEE)-guided cardioversion to prevent thromboembolic complications in patients with atrial fibrillation (AF) and effective anticoagulation (International Normalized Ratio of 2 or 3) at least three weeks before cardioversion. BACKGROUND: Transesophageal echocardiography has been proposed as a method of screening patients for left atrial thrombi before direct-current cardioversion of AF. The usefulness of TEE as a screening tool has always been evaluated in patients without long-term anticoagulation before cardioversion. METHODS: This prospective, single-center, observational study, performed on an intention-to-cardiovert basis, comprised 1,076 consecutive, unselected patients with AF. The initial two years were designed to be the control phase, during which the conventional approach was used. After that, cardioversion guided by TEE was performed in consecutive patients. RESULTS: The prevalence of left atrial thrombi was 7.7% in patients with persistent AF and effective anticoagulation. During the first four weeks after electrical cardioversion, six thromboembolic complications were observed in patients in whom the TEE-guided approach was employed (6 [0.8%] of 719 patients), compared with three thromboembolic complications in patients in whom the conventional approach was used (3 [0.8%] of 357 patients). None of the patients in whom electrical cardioversion was not performed experienced an embolic event. CONCLUSIONS: There were no differences in the rate of embolic events between the two treatment groups. In patients with AF and effective anticoagulation, TEE-guided electrical cardioversion does not reduce the embolic risk. However, TEE revealed left atrial thrombi in 7.7% of patients with AF and effective anticoagulation, before direct-current cardioversion.     

Peripheral T-cell lymphoma, not otherwise specified: a report of 340 cases from the International Peripheral T-cell Lymphoma Project

The International Peripheral T-cell Lymphoma Project is a collaborative effort to better understand peripheral T-cell lymphoma (PTCL). A total of 22 institutions submitted clinical and pathologic material on 1314 cases. One objective was to analyze the clinical and pathologic features of 340 cases of PTCL, not otherwise specified. The median age of the patients was 60 years, and the majority (69%) presented with advanced stage disease. Most patients (87%) presented with nodal disease, but extranodal disease was present in 62%. The 5-year overall survival was 32%, and the 5-year failure-free survival was only 20%. The majority of patients (80%) were treated with combination chemotherapy that included an anthracycline, but there was no survival advantage. The International Prognostic Index (IPI) was predictive of both overall survival and failure-free survival (P < .001). Multivariate analysis of clinical and pathologic prognostic factors, respectively, when controlling for the IPI, identified bulky disease (≥ 10 cm), thrombocytopenia (< 150 × 10(9)/L), and a high number of transformed tumor cells (> 70%) as adverse predictors of survival, but only the latter was significant in final analysis. Thus, the IPI and a single pathologic feature could be used to stratify patients with PTCL-not otherwise specified for novel and risk-adapted therapies.