49 research outputs found
Endothelium-targeted delivery of dexamethasone by anti-VCAM-1 SAINT-O-Somes in mouse endotoxemia
Microvascular endothelial cells play a pivotal role in the pathogenesis of sepsis-induced inflammatory responses and multiple organ failure. Therefore, they represent an important target for pharmacological intervention in the treatment of sepsis. Glucocorticosteroids were widely used in the treatment of sepsis but vast evidence to support their systemic use is lacking. The limited effects of glucocorticoids in the treatment of sepsis may be explained by differential effects of drug initiated NF-κB inhibition in different cell types and insufficient drug delivery in target cells. The current study aimed therefore to investigate the effects of an endothelial targeted delivery of dexamethasone in a mouse model of endotoxemia induced by two consecutive i.p. injections of lipopolysaccharide (LPS). To achieve endothelial cell specific delivery of dexamethasone, we modified SAINT-O-Somes, a new generation of liposomes that contain the cationic amphiphile SAINT-C18 (1-methyl-4-(cis-9-dioleyl) methyl-pyridinium chloride, with antibodies against vascular cell adhesion molecule-1 (VCAM-1). In LPS challenged mice, the systemic administration of free dexamethasone had negligible effects on the microvascular inflammatory endothelial responses. Dexamethasone-loaded anti-VCAM-1 SAINT-O-Somes specifically localized at VCAM-1 expressing endothelial cells in the microvasculature of inflamed organs. This was associated with a marginal attenuation of the expression of a few pro-inflammatory genes in kidney and liver, while no effects in the lung were observed. This study reveals that, although local accumulation of the targeted drug was achieved, endothelial targeted dexamethasone containing anti-VCAM-1 SAINT-O-Somes exhibited marginal effects on inflammatory endothelial cell activation in a model of endotoxemia. Studies with more potent drugs encapsulated into anti-VCAM-1 SAINT-O-Somes will in the future reveal whether this delivery system can be further developed for efficacious endothelial directed delivery of drugs in the treatment of sepsis
Leukocyte Counts, Myeloperoxidase, and Pregnancy-Associated Plasma Protein A as Biomarkers for Cardiovascular Disease: Towards a Multi-Biomarker Approach
We evaluated leukocyte counts and levels of CRP, fibrinogen, MPO, and PAPP-A in patients with stable and unstable angina pectoris, acute myocardial infarction, and healthy controls. All biomarkers were analyzed again after 6 months. Leukocyte counts and concentrations of fibrinogen, CRP, MPO, and PAPP-A were significantly increased in patients with acute myocardial infarction. Leukocyte counts and concentrations of MPO were significantly increased in patients with unstable angina pectoris compared with controls. After 6 months, leukocyte counts and MPO concentrations were still increased in patients with acute myocardial infarction when compared to controls. Discriminant analysis showed that leukocyte counts, MPO, and PAPP-A concentrations classified study group designation for acute coronary events correctly in 83% of the cases. In conclusion, combined assessment of leukocyte counts, MPO, and PAPP-A was able to correctly classify acute coronary events, suggesting that this could be a promising panel for a multibiomarker approach to assess cardiovascular risk
Telomere length in breast cancer patients before and after chemotherapy with or without stem cell transplantation
High-dose chemotherapy and peripheral blood stem cell transplantation (PBSCT) may accelerate telomere length loss in haematopoietic stem cells. As data including pre-and post-treatment samples are lacking, we studied leukocyte telomere length and telomerase activity before and after treatment in breast cancer patients randomized to receive 5 adjuvant courses FEC (5-FU, epirubicin and cyclophosphamide) (n= 17), or 4 × FEC followed by high-dose cyclophosphamide, thiotepa, carboplatin and autologous PBSCT (n= 16). Haemoglobin, MCV, leukocyte-and platelet numbers were assessed prior to (t0), 5 months after (t1) and 9 months after chemotherapy (t2); these parameters were decreased at t1 and t2 compared to t0(high-dose: all parameters; standard-dose: leukocytes and platelets), and all parameters were lower after high-dose than standard-dose treatment at t1. Paired individual leukocyte samples of t0 and t1 showed telomere length change (determined by telomere restricted fragment (TRF) assay) ranging from +0.8 to –2.2 kb, with a decreased TRF length in 9 patients of both groups. Telomerase activity (determined by TRAP assay) was below detection limit in leukocyte samples of t0 and t1. Thus, standard-and high-dose chemotherapy negatively affect haematological reconstitution in this setting. In individual patients, telomere length can be remarkably changed following haematological proliferative stress after treatment. © 2001 Cancer Research Campaign www.bjcancer.co
Fuelling conditions at staging sites can mitigate Arctic warming effects in a migratory bird
© 2018, The Author(s). Under climate warming, migratory birds should align reproduction dates with advancing plant and arthropod phenology. To arrive on the breeding grounds earlier, migrants may speed up spring migration by curtailing the time spent en route, possibly at the cost of decreased survival rates. Based on a decades-long series of observations along an entire flyway, we show that when refuelling time is limited, variation in food abundance in the spring staging area affects fitness. Bar-tailed godwits migrating from West Africa to the Siberian Arctic reduce refuelling time at their European staging site and thus maintain a close match between breeding and tundra phenology. Annual survival probability decreases with shorter refuelling times, but correlates positively with refuelling rate, which in turn is correlated with food abundance in the staging area. This chain of effects implies that conditions in the temperate zone determine the ability of godwits to cope with climate-related changes in the Arctic
Transcription factors and molecular epigenetic marks underlying EpCAM overexpression in ovarian cancer
BACKGROUND: The epithelial cell adhesion molecule (EpCAM) is overexpressed on carcinomas, and its downregulation inhibits the oncogenic potential of multiple tumour types. Here, we investigated underlying mechanisms of epcam overexpression in ovarian carcinoma. METHODS: Expression of EpCAM and DNA methylation (bisulphite sequencing) was determined for ovarian cancer cell lines. The association of histone modifications and 16 transcription factors with the epcam promoter was analysed by chromatin immunoprecipitation. Treatment with 5-Aza-2'-deoxycytidine (5-AZAC) was used to induce EpCAM expression. RESULTS: Expression of EpCAM was correlated with DNA methylation and histone modifications. Treatment with 5-AZAC induced EpCAM expression in negative cells. Ten transcription factors were associated with the epcam gene in EpCAM expressing cells, but not in EpCAM-negative cells. Methylation of an Sp1 probe inhibited the binding of nuclear extract proteins in electromobility shift assays; such DNA methylation sensitivity was not observed for an NF-kappa B probe. CONCLUSION: This study provides insights in transcriptional regulation of epcam in ovarian cancer. Epigenetic parameters associated with EpCAM overexpression are potentially reversible, allowing novel strategies for sustained silencing of EpCAM expression. British Journal of Cancer (2011) 105, 312-319. doi: 10.1038/bjc.2011.231 www.bjcancer.com Published online 21 June 2011 (C) 2011 Cancer Research U
Impact of a multidisciplinary approach to ultrasound-guided thyroid fine-needle aspiration biopsy at Tygerberg Hospital, Cape Town, South Africa: A retrospective audit
Background. Thyroid nodules are common and mostly benign. Inadequate sampling generally occurs in 13 - 17% of thyroid fine-needle aspiration biopsies (FNABs), but the proportion was found to be as high as 45% on evaluating 100 ultrasound (US)-guided FNABs in a previous unpublished audit at Tygerberg Hospital, Cape Town, South Africa (SA). Objectives. Primary aim: To determine the diagnostic yield of US-guided thyroid biopsy after implementing changes to existing practices, involving the creation of a specialised clinic and applying protocols for referral and FNAB. Secondary aim: To compare the results with other centres in SA. Methods. A retrospective audit of 178 thyroid biopsies was conducted. All US-guided thyroid biopsies performed in the specialised clinic between January 2017 and July 2018 were included. Data were analysed using descriptive statistics. Results. The 178 nodules were biopsied in 159 patients. The mean age was 53.7 years, with a gender ratio of 9.6:1 (female/male). A reduction in non-diagnostic biopsies was noted compared with the historical cohort (45% v. 32.6%). Sixty-one nodules (34.3%) had previously been biopsied with inadequate cytology results. When repeat biopsies were excluded, only 16.2% (n=19) were classified as insufficient. Conclusions. These findings illustrate the importance of the multidisciplinary approach and standardisation of the US-guided biopsy procedure and the value of consistency and quality control in a health system. While nodular thyroid disease is common and FNAB is relatively simple, early referral to a central specialised unit to minimise the incidence of inadequate FNAB should be considered
Thimet oligopeptidase as a potential CSF biomarker for Alzheimer's disease : A cross-platform validation study
Our previous antibody-based cerebrospinal fluid (CSF) proteomics study showed that Thimet oligopeptidase (THOP1), an amyloid beta (Aβ) neuropeptidase, was increased in mild cognitive impairment with amyloid pathology (MCI-Aβ+) and Alzheimer's disease (AD) dementia compared with controls and dementia with Lewy bodies (DLB), highlighting the potential of CSF THOP1 as an early specific biomarker for AD. We aimed to develop THOP1 immunoassays for large-scale analysis and validate our proteomics findings in two independent cohorts. We developed in-house CSF THOP1 immunoassays on automated Ella and Simoa platforms. The performance of the different assays were compared using Passing-Bablok regression analysis in a subset of CSF samples from the discovery cohort (n = 72). Clinical validation was performed in two independent cohorts (cohort 1: n = 200; cohort 2: n = 165) using the Ella platform. THOP1 concentrations moderately correlated between proteomics analysis and our novel assays (Rho > 0.580). In both validation cohorts, CSF THOP1 was increased in MCI-Aβ+ (>1.3-fold) and AD (>1.2-fold) compared with controls; and between MCI-Aβ+ and DLB (>1.2-fold). Higher THOP1 concentrations were detected in AD compared with DLB only when both cohorts were analyzed together. In both cohorts, THOP1 correlated with CSF total tau (t-tau), phosphorylated tau (p-tau), and Aβ40 (Rho > 0.540) but not Aβ42. Validation of our proteomics findings underpins the potential of CSF THOP1 as an early specific biomarker associated with AD pathology. The use of antibody-based platforms in both the discovery and validation phases facilitated the translation of proteomics findings, providing an additional workflow that may accelerate the development of biofluid-based biomarkers