eScholarship@UMMS

Syndicate content
Recent documents in eScholarship@UMMS
Updated: 2 hours 13 min ago

eScholarship@UMMS Promotional Poster

Thu, 02/26/2015 - 2:59pm

Poster created to promote eScholarship@UMMS, UMass Medical School's digital archive of research and scholarship, which is managed by the Lamar Soutter Library. The intended audience is faculty, researchers, staff, and students at UMass Medical School.

Can we early diagnose metabolic syndrome using brachial-ankle pulse wave velocity in community population

Tue, 02/24/2015 - 12:02pm

BACKGROUND: The prevalence of metabolic syndrome (MetS) increased recently and there was still not a screening index to predict MetS. The aim of this study was to estimate whether brachial-ankle pulse wave velocity (baPWV), a novel marker for systemic arterial stiffness, could predict MetS in Chinese community population.

METHODS: A total of 2 191 participants were recruited and underwent medical examination including 1 455 men and 756 women from June 2011 to January 2012. MetS was diagnosed according to the criteria of the International Diabetes Federation (IDF). Multiple Logistic regressions were conducted to explore the risk factors of MetS. Receiver operating characteristic (ROC) curve was performed to estimate the ideal diagnostic cutoff point of baPWV to predict MetS.

RESULTS: The mean age was (45.35+/-8.27) years old. In multiple Logistic regression analysis, the gender, baPWV and smoking status were risk factors to MetS after adjusting age, gender, baPWV, walk time and sleeping time. The prevalence of MetS was 17.48% in 30-year age population in Shanghai. There were significant differences (chi(2) = 96.46, P < 0.05) between male and female participants on MetS prevalence. According to the ROC analyses, the ideal cutoff point of baPWV was 1 358.50 cm/s (AUC = 60.20%) to predict MetS among male group and 1 350.00 cm/s (AUC = 70.90%) among female group.

CONCLUSION: BaPWV may be considered as a screening marker to predict MetS in community Chinese population and the diagnostic value of 1 350.00 cm/s was more significant for the female group.

Access to Healthy Food Stores Modifies Effect of a Dietary Intervention

Tue, 02/24/2015 - 12:02pm

BACKGROUND: Recent evidence suggests that opening a grocery store in a food desert does not translate to better diet quality among community residents.

PURPOSE: This study evaluated the influence of proximity to a healthy food store on the effect of a dietary behavioral intervention on diet among obese adults randomized to either a high fiber or American Heart Association diet intervention.

METHODS: Participants were recruited from Worcester County, Massachusetts, between June 2009 and January 2012. Dietary data were collected via 24-hour recalls at baseline and 3, 6, and 12 months post-intervention. Based on in-store inspection data, a store was considered as having adequate availability of healthy foods if it had at least one item available in each of 20 healthy food categories. Linear models evaluated maximum change in dietary outcomes in relation to road distance from residence to the nearest June healthy food store. The analysis was conducted in January to June 2014.

RESULTS: On average, participants (N = 204) were aged 52 years, BMI = 34.9, and included 72% women and 89% non-Hispanic whites. Shorter distance to a healthy food store was associated with greater improvements in consumption of fiber (b = -1.07 g/day per mile, p < 0.01) and fruits and vegetables (b = -0.19 servings/day per mile, p = 0.03) with and without covariate adjustment.

CONCLUSIONS: The effectiveness of dietary interventions is significantly influenced by the presence of a supportive community nutrition environment. Considering the nationwide efforts on promotion of healthy eating, the value of improving community access to healthy foods should not be underestimated.

Clinical Trial Registration Number: NCT00911885. Inc. All rights reserved.

Decrease in Glycemic Index Associated with Improved Glycemic Control among Latinos with Type 2 Diabetes

Tue, 02/24/2015 - 12:02pm

BACKGROUND: Glycemic index and glycemic load are used to facilitate glucose control among adults with type 2 diabetes, with a low glycemic index diet associated with improved glycemic control.

OBJECTIVE: To examine long-term longitudinal associations between changes in glycemic index and glycemic load with glycemic and metabolic control among Latino adults with diabetes.

DESIGN: Secondary data from intervention and comparison participants in the Latinos en Control trial (2006 to 2008) were analyzed.

PARTICIPANTS/SETTING: Data on dietary intake and metabolic characteristics were from low-income, Latino adults (N = 238; 87.7% Puerto Rican) with type 2 diabetes.

INTERVENTION: The Latinos en Control trial was a randomized clinical trial targeting diabetes self-management among Latinos with type 2 diabetes. Participants were randomized to a group-based behavioral intervention or usual care and followed through 12 months.

MAIN OUTCOME MEASURES: Outcomes included hemoglobin A1c (HbA1c) levels, fasting blood glucose, lipid profiles, anthropometrics, and blood pressure.

STATISTICAL ANALYSIS: Glycemic index and load were analyzed using data from three 24-hour dietary recalls conducted at baseline, 4 months, and 12 months. Repeated measures regression models were used to examine change in glycemic index and load associated with metabolic characteristics at 12 months. Covariates included sex, age, body mass index, blood pressure, total energy intake, medication use and intensity, physical activity, intervention status (intervention vs usual care), and time.

RESULTS: Increases in glycemic index from baseline to 12 months were associated with increased logarithm of HbA1c levels (beta = 0.003; P = 0.034) and waist circumference (beta = 0.12; P = 0.026) over time, but not with fasting glucose, blood lipids, or body mass index. There was modest evidence to support small, positive associations between glycemic load and HbA1c levels and waist circumference.

CONCLUSIONS: Lowering glycemic index is associated with improvements in certain metabolic risk factors among Latinos with diabetes. Targeting glycemic index may be an important component of dietary strategies for diabetes self-management. All rights reserved.

The association between dietary inflammatory index and risk of colorectal cancer among postmenopausal women: results from the Women's Health Initiative

Tue, 02/24/2015 - 12:02pm

PURPOSE: Inflammation is a process central to carcinogenesis and in particular to colorectal cancer (CRC). Previously, we developed a dietary inflammatory index (DII) from extensive literature review to assess the inflammatory potential of diet. In the current study, we utilized this novel index in the Women's Health Initiative to prospectively evaluate its association with risk of CRC in postmenopausal women.

METHODS: The DII was calculated from baseline food frequency questionnaires administered to 152,536 women aged 50-79 years without CRC at baseline between 1993 and 1998 and followed through 30 September 2010. Incident CRC cases were ascertained through a central physician adjudication process. Multiple covariate-adjusted Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95 % confidence intervals (95 % CI) for colorectal, colon (proximal/distal locations), and rectal cancer risk, by DII quintiles (Q).

RESULTS: During an average 11.3 years of follow-up, a total of 1,920 cases of CRC (1,559 colon and 361 rectal) were identified. Higher DII scores (representing a more pro-inflammatory diet) were associated with an increased incidence of CRC (HRQ5-Q1 1.22; 95 % CI 1.05, 1.43; p trend = 0.02) and colon cancer, specifically proximal colon cancer (HRQ5-Q1 1.35; 95 % CI 1.05, 1.67; p trend = 0.01) but not distal colon cancer (HRQ5-Q1 0.84; 95 % CI 0.61, 1.18; p trend = 0.63) or rectal cancer (HRQ5-Q1 1.20; 95 % CI 0.84, 1.72; p trend = 0.65).

CONCLUSION: Consumption of pro-inflammatory diets is associated with an increased risk of CRC, especially cancers located in the proximal colon. The absence of a significant association for distal colon cancer and rectal cancer may be due to the small number of incident cases for these sites. Interventions that may reduce the inflammatory potential of the diet are warranted to test our findings, thus providing more information for colon cancer prevention.

Single-component versus multicomponent dietary goals for the metabolic syndrome: a randomized trial

Tue, 02/24/2015 - 12:02pm

BACKGROUND: Few studies have compared diets to determine whether a program focused on 1 dietary change results in collateral effects on other untargeted healthy diet components.

OBJECTIVE: To evaluate a diet focused on increased fiber consumption versus the multicomponent American Heart Association (AHA) dietary guidelines.

DESIGN: Randomized, controlled trial from June 2009 to January 2014. (ClinicalTrials.gov: NCT00911885).

SETTING: Worcester, Massachusetts.

PARTICIPANTS: 240 adults with the metabolic syndrome.

INTERVENTION: Participants engaged in individual and group sessions.

MEASUREMENTS: Primary outcome was weight change at 12 months.

RESULTS: At 12 months, mean change in weight was -2.1 kg (95% CI, -2.9 to -1.3 kg) in the high-fiber diet group versus -2.7 kg (CI, -3.5 to -2.0 kg) in the AHA diet group. The mean between-group difference was 0.6 kg (CI, -0.5 to 1.7 kg). During the trial, 12 (9.9%) and 15 (12.6%) participants dropped out of the high-fiber and AHA diet groups, respectively (P = 0.55). Eight participants developed diabetes (hemoglobin A1c level > /=6.5%) during the trial: 7 in the high-fiber diet group and 1 in the AHA diet group (P = 0.066). LIMITATIONS: Generalizability is unknown. Maintenance of weight loss after cessation of group sessions at 12 months was not assessed. Definitive conclusions cannot be made about dietary equivalence because the study was powered for superiority.

CONCLUSION: The more complex AHA diet may result in up to 1.7 kg more weight loss; however, a simplified approach to weight reduction emphasizing only increased fiber intake may be a reasonable alternative for persons with difficulty adhering to more complicated diet regimens.

PRIMARY FUNDING SOURCE: National Heart, Lung, and Blood Institute.

Cutting Edge: AIM2 and Endosomal TLRs Differentially Regulate Arthritis and Autoantibody Production in DNase II-Deficient Mice

Mon, 02/23/2015 - 1:50pm

Innate immune pattern recognition receptors sense nucleic acids from microbes and orchestrate cytokine production to resolve infection. Inappropriate recognition of host nucleic acids also results in autoimmune disease. In this study, we use a model of inflammation resulting from accrual of self DNA (DNase II(-/-) type I IFN receptor [Ifnar](-/-)) to understand the role of pattern recognition receptor-sensing pathways in arthritis and autoantibody production. Using triple knockout (TKO) mice deficient in DNase II/IFNaR together with deficiency in either stimulator of IFN genes (STING) or absent in melanoma 2 (AIM2), we reveal central roles for the STING and AIM2 pathways in arthritis. AIM2 TKO mice show limited inflammasome activation and, similar to STING TKO mice, have reduced inflammation in joints. Surprisingly, autoantibody production is maintained in AIM2 and STING TKO mice, whereas DNase II(-/-) Ifnar(-/-) mice also deficient in Unc93b, a chaperone required for TLR7/9 endosomal localization, fail to produce autoantibodies to nucleic acids. Collectively, these data support distinct roles for cytosolic and endosomal nucleic acid-sensing pathways in disease manifestations.

Activated human T cells express alternative mRNA transcripts encoding a secreted form of RANKL

Mon, 02/23/2015 - 1:50pm

Receptor activator of nuclear factor-kappaB-ligand (RANKL), encoded by the gene TNFSF11, is required for osteoclastogenesis, and its expression is upregulated in pathologic bone loss. Transcript variants of TNFSF11 messenger RNA (mRNA) have been described that encode a membrane-bound and a putative secreted form of RANKL. We identify a TNFSF11 transcript variant that extends the originally identified transcript encoding secreted RANKL. We demonstrate that this TNFSF11 transcript variant is expressed by the human osteosarcoma cell line, Saos-2, and by both primary human T cells and Jurkat T cells. Of relevance to the production of RANKL in pathologic bone loss, expression of this secreted TNFSF11 transcript is upregulated in Jurkat T cells and primary human T cells upon activation. Furthermore, this transcript can be translated and secreted in Jurkat T cells in vitro and is able to support osteoclast differentiation. Our data highlight the complexity of the TNFSF11 genomic locus, and demonstrate the potential for the expression of alternate mRNA transcripts encoding membrane-bound and secreted forms of RANKL. Implications of alternate mRNA transcripts encoding different RANKL protein isoforms should be carefully considered and specifically examined in future studies, particularly those implicating RANKL in pathologic bone loss.

Osteoblast function is compromised at sites of focal bone erosion in inflammatory arthritis

Mon, 02/23/2015 - 1:50pm

In rheumatoid arthritis (RA), synovial inflammation results in focal erosion of articular bone. Despite treatment attenuating inflammation, repair of erosions with adequate formation of new bone is uncommon in RA, suggesting that bone formation may be compromised at these sites. Dynamic bone histomorphometry was used in a murine model of RA to determine the impact of inflammation on osteoblast function within eroded arthritic bone. Bone formation rates at bone surfaces adjacent to inflammation were similar to those observed in nonarthritic bone; therefore, osteoblast activity is unlikely to compensate for the increased bone resorption at these sites. Within arthritic bone, the extent of actively mineralizing surface was reduced at bone surfaces adjacent to inflammation compared with bone surfaces adjacent to normal marrow. Consistent with the reduction in mineralized bone formation, there was a notable paucity of cells expressing the mid- to late stage osteoblast lineage marker alkaline phosphatase, despite a clear presence of cells expressing the early osteoblast lineage marker Runx2. In addition, several members of the Dickkopf and secreted Frizzled-related protein families of Wnt signaling antagonists were upregulated in arthritic synovial tissues, suggesting that inhibition of Wnt signaling could be one mechanism contributing to impaired osteoblast function within arthritic bone. Together, these data indicate that the presence of inflammation within arthritic bone impairs osteoblast capacity to form adequate mineralized bone, thus contributing to the net loss of bone and failure of bone repair at sites of focal bone erosion in RA.

RANKL protein is expressed at the pannus-bone interface at sites of articular bone erosion in rheumatoid arthritis

Mon, 02/23/2015 - 1:50pm

OBJECTIVES: Receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG) have been demonstrated to be critical regulators of osteoclast generation and activity. In addition, RANKL has been implicated as an important mediator of bone erosion in rheumatoid arthritis (RA). However, the expression of RANKL and OPG at sites of pannus invasion into bone has not been examined. The present study was undertaken to further elucidate the contribution of this cytokine system to osteoclastogenesis and subsequent bone erosion in RA by examining the pattern of protein expression for RANKL, OPG and the receptor activator of NF-kappaB (RANK) in RA at sites of articular bone erosion.

METHODS: Tissues from 20 surgical procedures from 17 patients with RA were collected as discarded materials. Six samples contained only synovium or tenosynovium remote from bone, four samples contained pannus-bone interface with adjacent synovium and 10 samples contained both synovium remote from bone and pannus-bone interface with adjacent synovium. Immunohistochemistry was used to characterize the cellular pattern of RANKL, RANK and OPG protein expression immediately adjacent to and remote from sites of bone erosion.

RESULTS: Cellular expression of RANKL protein was relatively restricted in the bone microenvironment; staining was focal and confined largely to sites of osteoclast-mediated erosion at the pannus-bone interface and at sites of subchondral bone erosion. RANK-expressing osteoclast precursor cells were also present in these sites. OPG protein expression was observed in numerous cells in synovium remote from bone but was more limited at sites of bone erosion, especially in regions associated with RANKL expression.

CONCLUSIONS: The pattern of RANKL and OPG expression and the presence of RANK-expressing osteoclast precursor cells at sites of bone erosion in RA contributes to the generation of a local microenvironment that favours osteoclast differentiation and activity. These data provide further evidence implicating RANKL in the pathogenesis of arthritis-induced joint destruction.

TRANCE/RANKL knockout mice are protected from bone erosion in a serum transfer model of arthritis

Mon, 02/23/2015 - 1:50pm

There is considerable evidence that osteoclasts are involved in the pathogenesis of focal bone erosion in rheumatoid arthritis. Tumor necrosis factor-related activation-induced cytokine, also known as receptor activator of nuclear factor-kappaB ligand (TRANCE/RANKL) is an essential factor for osteoclast differentiation. In addition to its role in osteoclast differentiation and activation, TRANCE/RANKL also functions to augment T-cell dendritic cell cooperative interactions. To further evaluate the role of osteoclasts in focal bone erosion in arthritis, we generated inflammatory arthritis in the TRANCE/RANKL knockout mouse using a serum transfer model that bypasses the requirement for T-cell activation. These animals exhibit an osteopetrotic phenotype characterized by the absence of osteoclasts. Inflammation, measured by clinical signs of arthritis and histopathological scoring, was comparable in wild-type and TRANCE/RANKL knockout mice. Microcomputed tomography and histopathological analysis demonstrated that the degree of bone erosion in TRANCE/RANKL knockout mice was dramatically reduced compared to that seen in control littermate mice. In contrast, cartilage erosion was present in both control littermate and TRANCE/RANKL knockout mice. These results confirm the central role of osteoclasts in the pathogenesis of bone erosion in arthritis and demonstrate distinct mechanisms of cartilage destruction and bone erosion in this animal model of arthritis.

A longitudinal study of multicultural curriculum in medical education

Thu, 02/19/2015 - 7:50pm

OBJECTIVE: To evaluate impact a multicultural interclerkship had on students' perception of knowledge, interview skills, and empathy towards serving culturally diverse populations and role student demographics played in learning.

METHODS: Data extracted from students' self-reported course evaluations and pre/post questionnaires during multiculturalism interclerkship across 11 academic years. Inquired students' opinion about four areas: effectiveness, small group leaders, usefulness, and overall experience. Subscale and item ratings were compared using trend tests including multivariate analyses.

RESULTS: During studied years, 883 students completed course evaluation with high overall mean rating of 3.08 (S = 0.45) and subscale mean scores ranging from 3.03 to 3.30. Trends in three of four subscales demonstrated clear uptrend (p < 0.0001). Positive correlations between ratings of leaders and "usefulness" were observed (p < 0.0001). Pre/post matched dataset (n = 967) indicated majority of items (19/23) had statistically significant higher post interclerkship ratings compared to pre scores with nine of 19 having statistically significant magnitudes of change. Questionnaire had high overall reliability (Cronbach alpha = 0.8), and item-to-group correlations ranged from 0.40 to 0.68 (p < 0.0001).

CONCLUSIONS: By increasing students' exposure and interaction with diverse patients, their knowledge, attitude, and skills were increased and expanded in positive manner. These findings might inform those who are interested in enhancing this important competence. This is especially true given increasing scrutiny this global topic is receiving within and across healthcare professions around the world.

A survey study of evidence-based medicine training in US and Canadian medical schools

Thu, 02/19/2015 - 7:50pm

PURPOSE: The authors conducted a survey examining (1) the current state of evidence-based medicine (EBM) curricula in US and Canadian medical schools and corresponding learning objectives, (2) medical educators' and librarians' participation in EBM training, and (3) barriers to EBM training.

METHODS: A survey instrument with thirty-four closed and open-ended questions was sent to curricular deans at US and Canadian medical schools. The survey sought information on enrollment and class size; EBM learning objectives, curricular activities, and assessment approaches by year of training; EBM faculty; EBM tools; barriers to implementing EBM curricula and possible ways to overcome them; and innovative approaches to EBM education. Both qualitative and quantitative methods were used for data analysis. Measurable learning objectives were categorized using Bloom's taxonomy.

RESULTS: One hundred fifteen medical schools (77.2%) responded. Over half (53%) of the 900 reported learning objectives were measurable. Knowledge application was the predominant category from Bloom's categories. Most schools integrated EBM into other curricular activities; activities and formal assessment decreased significantly with advanced training. EBM faculty consisted primarily of clinicians, followed by basic scientists and librarians. Various EBM tools were used, with PubMed and the Cochrane database most frequently cited. Lack of time in curricula was rated the most significant barrier. National agreement on required EBM competencies was an extremely helpful factor. Few schools shared innovative approaches.

CONCLUSIONS: Schools need help in overcoming barriers related to EBM curriculum development, implementation, and assessment.

IMPLICATIONS: Findings can provide a starting point for discussion to develop a standardized competency framework.

UMCCTS Newsletter, February 2015

Wed, 02/11/2015 - 1:36pm

This is the February 2015 issue of the UMass Center for Clinical and Translational Science Newsletter containing news and events of interest.

Glioblastoma multiforme therapy and mechanisms of resistance

Wed, 02/11/2015 - 10:39am

Glioblastoma multiforme (GBM) is a grade IV brain tumor characterized by a heterogeneous population of cells that are highly infiltrative, angiogenic and resistant to chemotherapy. The current standard of care, comprised of surgical resection followed by radiation and the chemotherapeutic agent temozolomide, only provides patients with a 12-14 month survival period post-diagnosis. Long-term survival for GBM patients remains uncommon as cells with intrinsic or acquired resistance to treatment repopulate the tumor. In this review we will describe the mechanisms of resistance, and how they may be overcome to improve the survival of GBM patients by implementing novel chemotherapy drugs, new drug combinations and new approaches relating to DNA damage, angiogenesis and autophagy.

Evaluation of novel imidazotetrazine analogues designed to overcome temozolomide resistance and glioblastoma regrowth

Wed, 02/11/2015 - 10:39am

The cellular responses to two new temozolomide (TMZ) analogues, DP68 and DP86, acting against glioblastoma multiforme (GBM) cell lines and primary culture models are reported. Dose-response analysis of cultured GBM cells revealed that DP68 is more potent than DP86 and TMZ and that DP68 was effective even in cell lines resistant to TMZ. On the basis of a serial neurosphere assay, DP68 inhibits repopulation of these cultures at low concentrations. The efficacy of these compounds was independent of MGMT and MMR functions. DP68-induced interstrand DNA cross-links were demonstrated with H2O2-treated cells. Furthermore, DP68 induced a distinct cell-cycle arrest with accumulation of cells in S phase that is not observed for TMZ. Consistent with this biologic response, DP68 induces a strong DNA damage response, including phosphorylation of ATM, Chk1 and Chk2 kinases, KAP1, and histone variant H2AX. Suppression of FANCD2 expression or ATR expression/kinase activity enhanced antiglioblastoma effects of DP68. Initial pharmacokinetic analysis revealed rapid elimination of these drugs from serum. Collectively, these data demonstrate that DP68 is a novel and potent antiglioblastoma compound that circumvents TMZ resistance, likely as a result of its independence from MGMT and mismatch repair and its capacity to cross-link strands of DNA. Mol Cancer Ther; 14(1); 111-9. ©2014 AACR.

Evaluation of [In]-Labeled Zinc-Dipicolylamine Tracers for SPECT Imaging of Bacterial Infection

Tue, 02/10/2015 - 9:11pm

PURPOSE: This study prepared three structurally related zinc-dipicolylamine (ZnDPA) tracers with [111In] labels and conducted biodistribution and single-photon emission computed tomography/computed tomography (SPECT/CT) imaging studies of a mouse leg infection model.

PROCEDURES: Two monovalent tracers, ZnDPA-[111In]DTPA and ZnDPA-[111In]DOTA, each with a single zinc-dipicolylamine targeting unit, and a divalent tracer, Bis(ZnDPA)-[111In]DTPA, with two zinc-dipicolylamine units were prepared. Organ biodistribution and SPECT and CT imaging studies were performed on living mice with a leg infection created by injection of clinically relevant Gram positive Streptococcus pyogenes. Fluorescent and luminescent Eu3+-labeled versions of these tracers were also prepared and used to measure relative affinity for the exterior membrane surface of bacterial cells and mimics of healthy mammalian cells.

RESULTS: All three 111In-labeled radiotracers were prepared with a radiopurity of greater than 90%. The biodistribution studies showed that the two monovalent tracers were cleared from the body through the liver and kidney, with retained percentage injected dose for all organs of < 8% at 20h and infected leg target to non-target ratio (T/NT) ratio of greater than or equal to 3.0. Clearance of the divalent tracer from the bloodstream was slower and primarily through the liver, with a retained percentage injected dose for all organs greater than 37% at 20h and T/NT ratio rising to 6.2 after 20 h. The SPECT/CT imaging indicated the same large difference in tracer pharmacokinetics and higher accumulation of the divalent tracer at the site of infection.

CONCLUSIONS: All three [111In]-ZnDPA tracers selectively targeted the site of a clinically relevant mouse infection model that could not be discerned by visual external inspection of the living animal. The highest target selectivity, observed with a divalent tracer equipped with two zinc-dipicolylamine targeting units, compares quite favorably with the imaging selectivities previously reported for other nuclear tracers that target bacterial cell surfaces. The tracer pharmacokinetics depended heavily on tracer molecular structure suggesting that it may be possible to rapidly fine tune the structural properties for optimized in vivo imaging performance and clinical translation.

Her2/neu small interfering RNA delivered in culture by a streptavidin nanoparticle

Tue, 02/10/2015 - 9:11pm

A three-component nanoparticle consisting of biotinylated Trastuzumab antiHer2 antibody, tat transferring peptide and radiolabeled antisense oligomer, linked together through streptavidin, have shown promise in the delivery to Her2+ tumor in mice following intravenous administration and with evidence of radiotherapeutic efficacy. These results have encouraged us to consider the nanoparticle as a delivery vehicle for RNA interference therapy in which the radiolabeled antisense oligomer is replaced with an unlabeled siRNA duplex. The siRNA stability within the nanoparticle was first confirmed by incubation with RNase A. The interferon responses, that indicate off-target cytotoxicity, were evaluated by quantitative real-time RT-PCR in BT-474 (Her2+) human breast cancer cells by measuring the mRNA expression of 2', 5'-oligoadenylate synthetase (OAS1) and Stat-1, two key interferon-responsive genes. Thereafter the cytotoxicity induced by the siRNA nanoparticle was evaluated by a clonogenic survival assay in BT-474 cells while the Her2 expression of these target cells was evaluated for evidence of specific gene silencing. The siRNA within the three-component anti- Her2/neu siRNA nanoparticle was largely protected from RNase-dependent degradation and did not activate an interferon response. The nanoparticle effectively and significantly inhibited colony formation of the target cells and silenced the Her2 gene expression at 5 nM compared with the identical nanoparticle with a scrambled siRNA. Our delivery nanoparticle, with tumor targeting provided by the antibody and its accumulation without entrapment, possibly due to the transfecting peptide, delivered an siRNA duplex to the proper subcellular localization for specific and effective gene silencing in culture by what appears to be an siRNA mechanism.

Activin-like kinase 3 is important for kidney regeneration and reversal of fibrosis

Tue, 02/10/2015 - 9:11pm

Molecules associated with the transforming growth factor beta (TGF-beta) superfamily, such as bone morphogenic proteins (BMPs) and TGF-beta, are key regulators of inflammation, apoptosis and cellular transitions. Here we show that the BMP receptor activin-like kinase 3 (Alk3) is elevated early in diseased kidneys after injury. We also found that its deletion in the tubular epithelium leads to enhanced TGF-beta1-Smad family member 3 (Smad3) signaling, epithelial damage and fibrosis, suggesting a protective role for Alk3-mediated signaling in the kidney. A structure-function analysis of the BMP-Alk3-BMP receptor, type 2 (BMPR2) ligand-receptor complex, along with synthetic organic chemistry, led us to construct a library of small peptide agonists of BMP signaling that function through the Alk3 receptor. One such peptide agonist, THR-123, suppressed inflammation, apoptosis and the epithelial-to-mesenchymal transition program and reversed established fibrosis in five mouse models of acute and chronic renal injury. THR-123 acts specifically through Alk3 signaling, as mice with a targeted deletion for Alk3 in their tubular epithelium did not respond to therapy with THR-123. Combining THR-123 and the angiotensin-converting enzyme inhibitor captopril had an additive therapeutic benefit in controlling renal fibrosis. Our studies show that BMP signaling agonists constitute a new line of therapeutic agents with potential utility in the clinic to induce regeneration, repair and reverse established fibrosis.

Radiolabeled Zn-DPA as a potential infection imaging agent

Tue, 02/10/2015 - 9:11pm

INTRODUCTION: A zinc-dipicolylamine analog (Zn-DPA) conjugated with a fluorophore (PSVue(R)794) has been shown to image bacterial infections in mice. However, radiolabeled Zn-DPA has not previously been considered for nuclear imaging of infection.

METHODS: Both 111In-labeled DOTA-biotin and Zn-DPA-biotin were combined using streptavidin (SA) as a noncovalent linker. Mice injected intramuscularly with Streptococcus pyogenes (infection model) or with lipopolysaccharide (LPS) (inflammation model) were coinjected intravenously with 6 mug of DPA as PSVue794 and as 111In-DOTA-biotin/SA/biotin-Zn-DPA. Periodic fluorescent and SPECT (single photon emission computed tomography)/CT (computed tomography) images were acquired, and biodistributions were obtained at 22 h.

RESULTS: Histological examination confirmed the validity of both the infection and inflammation animal models. Both the whole-body optical and nuclear images showed obvious accumulations in the target thigh in both models at all time points. At 22 h, the average target thigh accumulation of 111In was 1.66%ID/g (S.D. 0.15) in the infection mice compared to 0.58%ID/g (S.D. 0.07) in the inflammation mice (P < .01), and the 111In target/normal thigh ratio was 2.8 fold higher in the infection animals compared to the inflammation animals.

CONCLUSIONS: These preliminary results show that Zn-DPA within streptavidin targets S. pyogenes-infected mice similarly to its free fluorescent analogue. The significantly higher accumulation in the live bacterial infection thigh compared to that of the LPS-induced inflammation thigh suggests that Zn-DPA may be a promising imaging agent to distinguish between bacterial infections and sterile inflammations.