Collagen-based Tissue Engineering as Applied to Heart Valves

Using the method of directed collagen gel shrinkage, we have been fabricating heart valves and mitral valve chordae [1,2,3]. The principle involves mixing solubilized collagen with the appropriate cells. When the collagen-cell mixture is neutralized, soluble collagen reassembles into fibrils and a gel is created. When the gel is mechanically constrained, the collagen fibrils align in the direction of constraint. The generation of tensile force during contraction is crucial for the formation of highly aligned, compacted collagenous constructs. So far, inappropriate mechanical properties have been one of the main limitations of most collagen-based tissue equivalents. In this study, we focused on providing both biomechanical and biochemical stimuli to increase cellular proliferation, matrix synthesis, and hence improve the mechanical properties of the collagen constructs. We explored a number of holder materials and configurations, with an objective to maximize the lateral compaction of our constructs. We designed a bioreactor that can provide controlled static tension to our collagen constructs. We also developed a nutrition-fortified medium that includes trace elements (Zn2+, Cu2+, Fe2+ and Mn2+), various amino acids, and vitamins (A, B complex, and C). Our ultimate goal was to combine biomechanical and biochemical stimuli, and enhance the mechanical strength of our collagen constructs.

Upgrades of the high resolution imaging x-ray crystal spectrometers on experimental advanced superconducting tokamak

Two imaging x-ray crystal spectrometers, the so-called "poloidal" and "tangential" spectrometers, were recently implemented on experimental advanced superconducting tokamak (EAST) to provide spatially and temporally resolved impurity ion temperature (T(i)), electron temperature (T(e)) and rotation velocity profiles. They are derived from Doppler width of W line for Ti, the intensity ratio of Li-like satellites to W line for Te, and Doppler shift of W line for rotation. Each spectrometer originally consisted of a spherically curved crystal and a two-dimensional multi-wire proportional counter (MWPC) detector. Both spectrometers have now been upgraded. The layout of the tangential spectrometer was modified, since it had to be moved to a different port, and the spectrometer was equipped with two high count rate Pilatus detectors (Model 100 K) to overcome the count rate limitation of the MWPC and to improve its time resolution. The poloidal spectrometer was equipped with two spherically bent crystals to record the spectra of He-like and H-like argon simultaneously and side by side on the original MWPC. These upgrades are described, and new results from the latest EAST experimental campaign are presented.

Protective efficacy evaluation induced by recombinant protein LHD-Sj23-GST of Schistosoma japonicum emulsified with three different adjuvants

As a complement to chemotherapy and other control approaches, the development of an effective vaccine is necessary to combat Schistosomiasis japonica that remains a serious public health problem in China. In the present study, mice were vaccinated with purified recombinant protein LHD-Sj23-GST (large hydrophilic domain of 23 kDa antigen of S. japonicum fused with Sj26GST) emulsified with Freund's adjuvant (FA), Montanide ISA 206 and Montanide ISA 70 M and challenged with cercariae, the protective efficacy induced by the recombinant protein was evaluated, and the LHD-Sj23-GST-specific IgG and its subtypes were determined. The result revealed that a significant worm burden reduction (58.8%, 26.3% and 54.3%; P<0.05) was obtained in mice vaccinated with LHD-Sj23-GST emulsified with three different adjuvants compared to those mice treated with respective adjuvant only. ELISA test suggested that the high-level production of LHD-Sj23-GST-specific IgG1, IgG2a and IgG3 antibodies may participate in protecting against schistosome infection.

Association of polymorphisms in interleukin-18 and interleukin-28B with hepatitis B recurrence after liver transplantation in Chinese Han population

Interleukin-18 (IL-18) is a potent proinflammatory cytokine, which can promote hepatitis B virus clearance. The latest studies find that genetic polymorphisms near the IL-28B gene are strongly associated with sustained viral response and spontaneous viral clearance in patients with chronically infected hepatitis C and hepatitis B. We investigated the effect of rs187238 and rs1946518 in IL-18 gene and rs8099917 in IL-28B gene on HBV recurrence in liver transplant patients. A total of 200 liver transplant recipients and relevant donors were enrolled in this study. The patients' mean follow-up was 39 month (range 10-65 month). All liver transplant recipients were in a stable stage. The total recipients (n = 200) were divided into end-stage liver disease secondary to hepatitis B (n = 140) and end-stage liver disease secondary to other diseases (n = 60) before transplantation. Recipients (n = 140) with hepatitis B before transplantation were defined to nonHBV recurrence group (n = 119) or HBV recurrence group (n = 21), which was positive for HBsAg or elevatory in HBV DNA (>2.0 × 10(2) IU mL(-1)) after transplantation. For the recipients (n = 140) had hepatitis B before transplantation, we studied the single-nucleotide polymorphisms (SNPs) of IL-18 gene (rs187238 and rs1946518) and IL-28B gene (rs8099917) by high-resolution melting (HRM) curve analysis. The serum levels of IL-18 and IFN-γ were tested by ELISA. The serums levels of IFN-γ were lower in HBV recurrence group than that in nonHBV recurrence group (P < 0.01). The genotype of IL-28B gene rs8099917 was associated with alanine aminotransferase (ALT) levels and aspartate aminotransferase (AST) levels in HBV-related liver transplant recipients (n = 140). The recipients with allele G (GG+GT) had higher ALT and AST levels (P < 0.05). No association was found between IL-18 gene and IL-28B gene polymorphisms with HBV recurrence in the liver transplant recipients or the donors. We identified that the IFN-γ was a protective factor of HBV recurrence after liver transplantation. The allele G of rs8099917 was associated with hepatitis B-related hepatocytes injury. The rs8099917 G allele subgroup should reinforce antiviral therapy.

Prospective study of thrombospondin-1 mimetic peptides, ABT-510 and ABT-898, in dogs with soft tissue sarcoma

BACKGROUND

Exposure to anti-angiogenic thrombospondin-1 (TSP-1) mimetic peptides (MPs) has resulted in sporadic anti-tumor activity in humans and dogs.

HYPOTHESIS

Novel TSP-1 MPs formulations will be safe, tolerated, and clinically active in soft tissue sarcoma (STS) in dogs.

ANIMALS

Sixty-two client-owned dogs with measurable STS were enrolled, excluding hemangiosarcoma.

METHODS

A prospective, single agent, multicenter, open-label study assessing ABT-510 bolus, ABT-898 bolus, or ABT-898 depot formulations of TSP-1 in dogs. Endpoints included tolerability, antitumor activity, and the assessment of ability of clinical covariates and circulating endothelial cells (CEC) concentration to predict tumor response.

RESULTS

Two non-dose-limiting toxicoses possibly attributed to treatment were observed (keratitis and osteoarthritis). Antitumor activity (10/44 = 23% responses) was observed in study subjects who received treatment for >28 days (n = 44) including both partial (7) and minimal responses (3). Responses were disproportionately seen in dogs receiving ABT-898 formulations (9/28 = 32%) versus those receiving ABT-510 (1/16 = 6%; P < .045). Disease stabilization for >84 days was also documented (8/44 = 18%). Slow rates of tumor progression before study entry correlated with anti-tumor activity in treated dogs, whereas no significant association was found between changes in total CEC concentration and tumor response (P = .28) or time to progression (P = .42).

CONCLUSIONS AND CLINICAL IMPORTANCE

Safely achieved antitumor activity was documented with TSP-1 MPs in dogs with STS. The most notable activity was achieved with the ABT-898 formulations.

Movement variability resulting from different noise sources: a simulation study

Limb movements are highly variable due in part to noise occurring at different stages of movement production, from sensing the position of the limb to the issuing of motor commands. Here we used a simulation approach to predict the effects of noise associated with (1) sensing the position of the limb ('position sensing noise') and (2) planning an appropriate movement vector ('trajectory planning noise'), as well as the combined effects of these factors, on arm movement variability across the workspace. Results were compared to those predicted by a previous model of the noise associated with movement execution. We found that the effects of sensing and planning related noise on movement variability were highly dependent upon both the planned movement direction and the initial configuration of the arm and differed in several respects from the effects of execution noise. In addition, sensing and planning noise interacted in a complex manner across movement directions. These results provide important insights into the relative roles of sensing, planning and execution noise in movement variability that could prove useful for understanding and addressing the exaggerated variability that arises from neurological damage, and for interpreting neurophysiological investigations that seek to relate neural variability to behavioral variability.

Lysine-specific demethylase 1: an epigenetic regulator of salt-sensitive hypertension

BACKGROUND

Hypertension (HTN) represents a complex heritable disease in which environmental factors may directly affect gene function via epigenetic mechanisms. The aim of this study was to test the hypothesis that dietary salt influences the activity of a histone-modifying enzyme, lysine-specific demethylase 1 (LSD-1), which in turn is associated with salt-sensitivity of blood pressure (BP).

METHODS

Animal and human studies were performed. Salt-sensitivity of LSD-1 expression was assessed in wild-type (WT) and LSD-1 heterozygote knockout (LSD-1(+/-)) mice. Clinical relevance was tested by multivariate associations between single-nuclear polymorphisms (SNPs) in the LSD-1 gene and salt-sensitivity of BP, with control of dietary sodium, in a primary African-American hypertensive cohort and two replication hypertensive cohorts (Caucasian and Mexican-American).

RESULTS

LSD-1 expression was modified by dietary salt in WT mice with lower levels associated with liberal salt intake. LSD-1(+/-) mice expressed lower LSD-1 protein levels than WT mice in kidney tissue. Similar to LSD-1(+/-) mice, African-American minor allele carriers of two LSD-1 SNPs displayed greater change in systolic BP (SBP) in response to change from low to liberal salt diet (rs671357, P = 0.01; rs587168, P = 0.005). This association was replicated in the Hispanic (rs587168, P = 0.04) but not the Caucasian cohort. Exploratory analyses demonstrated decreased serum aldosterone concentrations in African-American minor allele carriers similar to findings in the LSD-1(+/-) mice, decreased α-EnaC expression in LSD-1(+/-) mice, and impaired renovascular responsiveness to salt loading in minor allele carriers.

CONCLUSION

The results of this translational research study support a role for LSD-1 in the pathogenesis of salt-sensitive HTN.

CM2 antigen, a potential novel molecule participating in glucuronide transport on rat hepatocyte canalicular membrane

The polarized molecules predominately distributing at hepatocyte canalicular surface play a vital role in disclosing the process of bile formation and etiopathogenisis of cholestatic live diseases. Therefore, it is important to find novel polarized molecules on hepatocyte canalicular membrane. In the present study, canalicular membrane vesicles (CMVs) isolated from rat hepatocyte by density gradient centrifugation were used as immunogens to produce hybridoma and 46 strains of monoclonal antibodies (mAb) against CMVs were obtained. With a series of morphological assay methods, including immunohistochemistry, immunofluorescence and immuno-electron microscope, the antigens recognized by canalicular mAb1 (CM1) and canalicular mAb2 (CM2) were confirmed to predominately distribute at hepatocyte canalicular membrane. Transport activity assay revealed that CM2 could inhibit ATP-dependent E217βG uptake of rat hepatocyte CMVs. Meanwhile, Western blotting analysis showed that the molecular mass of CM2 antigen was approximately 110kDa, which was much less than Mr 180kDa of multidrug resistance-associated protein 2 (MRP2) involved in glucuronide transport. These data indicated that CM2 antigen might be a potential novel molecule participating in glucuronide transport on the hepatocyte canalicular membrane.

MicroRNA-7 functions as an anti-metastatic microRNA in gastric cancer by targeting insulin-like growth factor-1 receptor

Metastasis is a major clinical obstacle in the treatment of gastric cancer (GC) and it accounts for the majority of cancer-related mortality. MicroRNAs have recently emerged as regulators of metastasis by acting on multiple signaling pathways. In this study, we found that miR-7 is significantly downregulated in highly metastatic GC cell lines and metastatic tissues. Both gain-of-function and loss-of-function experiments showed that increased miR-7 expression significantly reduced GC cell migration and invasion, whereas decreased miR-7 expression dramatically enhanced cell migration and invasion. In vivo metastasis assays also demonstrated that overexpression of miR-7 markedly inhibited GC metastasis. Moreover, the insulin-like growth factor-1 receptor (IGF1R) oncogene, which is often mutated or amplified in human cancers and functions as an important regulator of cell growth and tumor invasion, was identified as a direct target of miR-7. Silencing of IGF1R using small interefering RNA (siRNA) recapitulated the anti-metastatic function of miR-7, whereas restoring the IGF1R expression attenuated the function of miR-7 in GC cells. Furthermore, we found that suppression of Snail by miR-7, through targeting IGF1R, increased E-cadherin expression and partially reversed the epithelial-mesenchymal transition (EMT). Finally, analyses of miR-7 and IGF1R levels in human primary GC with matched lymph node metastasis tissue arrays revealed that miR-7 is inversely correlated with IGF1R expression. The present study provides insight into the specific biological behavior of miR-7 in EMT and tumor metastasis. Targeting this novel miR-7/IGF1R/Snail axis would be helpful as a therapeutic approach to block GC metastasis.

First Report of the Lesion Nematode, Pratylenchus agilis, Parasitizing Wheat in China

Wheat (Triticum aestivum L.) fields in Zhengzhou, Henan Province that exhibited reduced height and number of tillers were surveyed in 2008, and samples were collected for analyses. Fifteen of thirty-five samples contained a nematode suspected of causing small, brown lesions in roots. Both lateral roots and root hairs were reduced in infected plants. Nematode presence was associated with enlarging lesions and necrotic roots. We also observed lesion nematode infestation in samples with no symptoms in the roots. During the growing season, wheat yield increased by 14% with nematocide treatments in Zhengzhou suburb fields. The morphological and molecular analyses of the nematodes isolated from soil samples established the identity of the species as the lesion nematode, Pratylenchus agilis (2,3). Morphological characteristics that were used for identification included female body, lip annules, tail terminus, number of lines in the lateral field, stylet knobs, stylet length, and vulva location in relation to body length. Females were cylindrical, measured 452 to 811 μm long, and contained two lip annules, a smooth tail terminus, four lateral lines, a vulva at 72.64 to 79.97%, a stylet of 16.20 to 17.55 μm, basal esophageal lobes elongated less than twice the body width, and stylet knobs rounded posteriorly. Males were rare and the spermatheca was empty. Molecular analysis was conducted by amplifying the internal transcribed spacer (ITS) regions ITS1 and 2. Sequence of ITS regions from this population (GenBank Accession No. JQ039330) showed highest sequence homology to P. agilis isolate PagKL5 (GenBank Accession No. FJ71289.1) with the identity of 90%. High variability at species level has been found for Pratylenchus species (1). On the basis of the morphological traits and molecular analyses, the nematodes were identified as P. agilis. To our knowledge, this is the first report of P. agilis parasitizing wheat. References: (1) F. De Luca et al. Eur. J. Plant Pathol. 130:415, 2011. (2) A. M. Golden et al. Plant Dis. Rep. 62:430, 1978. (3) R. V. Rebois et al. J. Nematol. 18:392, 1986.