36 research outputs found
Predicting Risk of End-Stage Liver Disease in Antiretroviral-Treated HIV/Hepatitis C Virus-Coinfected Patients
Background. End-stage liver disease (ESLD) is an important cause of morbidity among HIV/hepatitis C virus (HCV)-coinfected patients. Quantifying the risk of this outcome over time could help determine which coinfected patients should be targeted for risk factor modification and HCV treatment. We evaluated demographic, clinical, and laboratory variables to predict risk of ESLD in HIV/HCV-coinfected patients receiving antiretroviral therapy (ART). Methods. We conducted a retrospective cohort study among 6,016 HIV/HCV-coinfected patients who received ART within the Veterans Health Administration between 1997 and 2010. The main outcome was incident ESLD, defined by hepatic decompensation, hepatocellular carcinoma, or liver-related death. Cox regression was used to develop prognostic models based on baseline demographic, clinical, and laboratory variables, including FIB-4 and aspartate aminotransferase-to-platelet ratio index, previously validated markers of hepatic fibrosis. Model performance was assessed by discrimination and decision curve analysis. Results. Among 6,016 HIV/HCV patients, 532 (8.8%) developed ESLD over a median of 6.6 years. A model comprising FIB-4 and race had modest discrimination for ESLD (c-statistic, 0.73) and higher net benefit than alternative strategies of treating no or all coinfected patients at relevant risk thresholds. For FIB-4 \u3e3.25, ESLD risk ranged from 7.9% at 1 year to 26.0% at 5 years among non-blacks and from 2.4% at 1 year to 14.0% at 5 years among blacks. Conclusions. Race and FIB-4 provided important predictive information on ESLD risk among HIV/HCV patients. Estimating risk of ESLD using these variables could help direct HCV treatment decisions among HIV/HCV-coinfected patients
Wound dressings for a proteolytic-rich environment
Wound dressings have experienced continuous and significant changes over the years based on the knowledge of the biochemical events associated with chronic wounds. The development goes from natural
materials used to just cover and conceal the wound to interactive materials that can facilitate the healing process, addressing specific issues in non-healing wounds. These
new types of dressings often relate with the proteolytic wound environment and the bacteria load to enhance the healing. Recently, the wound dressing research is focusing on the replacement of synthetic polymers by natural protein materials to delivery bioactive agents to the wounds. This
article provides an overview on the novel protein-based wound dressings such as silk fibroin keratin and elastin.
The improved properties of these dressings, like the release of antibiotics and growth factors, are discussed. The different types of wounds and the effective parameters of
healing process will be reviewed
Intranasal administration of elastin-like polypeptide for therapeutic delivery to the central nervous system
Jeremy WD McGowan,1 Qingmei Shao,1 Parminder JS Vig,1,2 Gene L Bidwell III1,2 1Department of Neurology, 2Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS, USA Abstract: Bypassing the blood–brain barrier is one of the primary considerations when designing compounds intended to function in the central nervous system (CNS). Intranasal (IN) administration of otherwise blood–brain barrier impermeable molecules can result in high CNS concentrations and low systemic accumulation, indicating that IN administration may be a useful method of delivering therapeutics to the CNS. Elastin-like polypeptide (ELP) is a large, non-immunogenic, highly manipulable biopolymer with extensive evidence supporting its use as a carrier with the ability to improve drug pharmacokinetics and drug targeting. The ability of ELP to reach the CNS via IN administration has been shown previously. Previous studies have also identified the ability of cell penetrating peptides (CPPs) to increase the uptake of molecules in some instances, including via the IN route. Here, we compared and contrasted the biodistribution of ELPs with or without addition of the CPPs Tat or SynB1 via both the IN and intravenous routes. Administration of ELP via the IN route led to significant accumulation in the brain, especially in the olfactory bulbs. When injected intravenously, <3% of the ELP signal was present outside the vascular compartment. This contrasted with IN administration, which resulted in 79% of the fluorescence signal localized outside the vascular space. The fusion of Tat or SynB1 significantly altered the biodistribution of ELP, decreasing the total CNS accumulation following IN administration. The addition of CPPs to ELP increased their retention in the nasal epithelium. These results suggest ELP may represent an effective CNS delivery vector without further modification and that the addition of a CPP significantly influences biodistribution. Keywords: central nervous system, cell penetrating peptide, elastin-like polypeptide, intranasal administration, drug delivery, blood–brain barrie
Thermally Targeted Delivery of a c-Myc Inhibitory Polypeptide Inhibits Tumor Progression and Extends Survival in a Rat Glioma Model
<div><p>Treatment of glioblastoma is complicated by the tumors’ high resistance to chemotherapy, poor penetration of drugs across the blood brain barrier, and damaging effects of chemotherapy and radiation to normal neural tissue. To overcome these limitations, a thermally responsive polypeptide was developed for targeted delivery of therapeutic peptides to brain tumors using focused hyperthermia. The peptide carrier is based on elastin-like polypeptide (ELP), which is a thermally responsive biopolymer that forms aggregates above a characteristic transition temperature. ELP was modified with cell penetrating peptides (CPPs) to enhance delivery to brain tumors and mediate uptake across the tumor cells’ plasma membranes and with a peptide inhibitor of c-Myc (H1). In rats with intracerebral gliomas, brain tumor targeting of ELP following systemic administration was enhanced up to 5-fold by the use of CPPs. When the lead CPP-ELP-fused c-Myc inhibitor was combined with focused hyperthermia of the tumors, an additional 3 fold increase in tumor polypeptide levels was observed, and 80% reduction in tumor volume, delayed onset of tumor-associated neurological deficits, and at least doubled median survival time including complete regression in 80% of animals was achieved. This work demonstrates that a c-Myc inhibitory peptide can be effectively delivered to brain tumors.</p> </div
Inhibition of Glioma Cell Proliferation by CPP-ELP-H1 Polypeptides <i>in vitro</i>.
<p>C6 cells were exposed to various concentrations of Bac-ELP1-H1 (<b>A</b>) or SynB1-ELP1-H1 (<b>B</b>) at 37°C or 42°C for 1 h, and cell number was determined 72 h later. <b>C.</b> C6, D54, or U-87 MG cells were exposed to 40 µM Bac-ELP1-H1 for 1 h at 37°C or 42°C, and cell number was determined 72 h later. Bars, s.e.m. *, Heated and unheated treatments significantly different (p<0.01, Student’s t-test).</p
Enhancement of Bac-ELP1-H1 Tumor Uptake by Thermal Targeting.
<p>Following IV administration of Alexa750-labeled Bac-ELP1-H1 or Bac-ELP2-H1 with or without hyperthermia, tumor and organ levels were determined by <i>ex vivo</i> whole organ fluorescence imaging. <b>A.</b> Representative images of brains from each treatment group. <b>B.</b> Quantitation of tumor fluorescence from each group. <b>C.</b> Quantitation of fluorescence from tumor and all major organs. Bars, s.e.m. *, Fluorescence levels are statistically different (p<0.01, one way ANOVA with post hoc Bonferroni, n = 4 rats/group).</p