Effect of fenofibrate on diabetic retinopathy in rats via SIRT1/NF-κB signaling pathway

OBJECTIVE

To explore the influence of fenofibrate on the diabetic retinopathy (DR) in rats via the sirtuin1 (SIRT1)/nuclear factor-κB (NF-κB) signaling pathway.

PATIENTS AND METHODS

A total of 30 SD rats were divided into group A (DR group), group B (fenofibrate treatment group) and group C (Healthy group). Rats in group A were intraperitoneally injected with 50 mg/kg streptozotocin (STZ) for 5 days without feeding. After fasting for 2 days, blood was drawn from the tail veins of the rats to measure blood glucose, and blood glucose ≥16.7 mmol/L represented that the model was eligible. Those in group B were injected with STZ and nourished with the mixed feed containing fenofibrate (10 mg/kg). Those in group C were intraperitoneally injected with normal saline and set as negative control group. The retinal structure of rats in the three groups was observed via immunohistochemical staining, and the apoptosis of retinal ganglion cells (RGCs) was evaluated via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Moreover, the protein expressions of Sirtuin1 (SIRT1) and NF-κB were detected using immunofluorescence assay and Western blotting.

RESULTS

According to the immunohistochemical staining results, rats in group C had intact retinal nuclear layer tissues without phenomena such as fracture, disorderly arrangement, blur structures, and nerve fiber layer edema. Those in group A exhibited fracture of retinal nuclear layer tissues, disorderly arranged cells, blur retinal structures at all layers, and a quite evident nerve fiber layer edema. Compared to that in group A, the nerve fiber layer edema in group B was significantly improved. The TUNEL assay results revealed that compared to normal rats in group C, those in group A and group B had apoptotic RGCs. Additionally, the number of apoptotic cells was the largest in group A, and compared to that in group A, it was notably reduced in group B after treatment with fenofibrate. According to the immunofluorescence assay results, after being treated with fenofibrate, rats in group B showed a significantly lower protein expression level of NF-κB in the retina than in group A. Based on the Western blotting detection results, the protein expression level of NF-κB in group B was evidently lower than that in group A, and was the highest in group A and the lowest in group C. Compared to that in group C, the protein expression level of SIRT1 in group B was increased.

CONCLUSIONS

Fenofibrate facilitates the expression of SIRT1 in the retinal tissues to reduce the NF-κB activity, thereby treating DR in rats.

Long non-coding RNA TOB1-AS1 modulates cell proliferation, apoptosis, migration and invasion through miR-23a/NEU1 axis via Wnt/b-catenin pathway in gastric cancer

OBJECTIVE

Gastric cancer (GC) is the fourth common cancer worldwide. Long non-coding RNA TOB1 antisense RNA 1 (TOB1-AS1) has been found to participate in the process of GC, while the precise role of TOB1-AS1 is still not understood in GC progression.

MATERIALS AND METHODS

We collected 21-paired GC and para-carcinoma tissue specimens, and the levels of TOB1-AS1 and lysosomal sialidase (NEU1) were detected by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). The protein expression levels of NEU1, b-catenin, c-Myc, Cyclin D1, N-cadherin were determined via Western blot. Cell proliferation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Flow cytometry was performed to evaluate cell proliferation. Besides, GC cell migration and invasion capacities were identified by transwell assay. Dual-Luciferase reporter assay was employed to examine the interrelation between miR-23a and TOB1-AS1 or NEU1. Finally, the role of TOB1-AS1 was verified in vivo.

RESULTS

The levels of TOB1-AS1 were decreased in GC tissues and cell lines. Either TOB1-AS1 or NEU1 upregulation accelerated GC cell apoptosis, hampered proliferation, migration, and invasion. Further, the role of TOB1-AS1 silencing on cell behaviors was abrogated by NEU1 upregulation. TOB1-AS1 and NEU1 exerted their roles via Wnt/b-catenin signaling pathway. Overexpression of TOB1-AS1 blocked GC development in vivo. Mechanically, miR-23a was targeted by TOB1-AS1, but directly targeted NEU1.

CONCLUSIONS

TOB1-AS1/miR-23a/NEU1 axis regulated proliferation, apoptosis, migration, and invasion of GC cells via Wnt/b-catenin pathway, providing the evidence for serving TOB1-AS1 as an underlying therapeutic target in human GC treatment.

MiR-181d inhibits cell proliferation and metastasis through PI3K/AKT pathway in gastric cancer

OBJECTIVE

Gastric cancer is the second highest mortality tumor and the fourth most common cancer worldwide that has high aggressiveness. MicroRNA-181d (miR-181d) has been established to be a tumor suppressor, by suppressing cell proliferation, cell cycle, and promoting apoptosis in several cancers. The purpose of this study is to explore the great roles of miR-181d in gastric cancer.

PATIENTS AND METHODS

The Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) and Western blot were applied to calculate the mRNA and protein levels of miR-181d and genes. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) and transwell assays were utilized to measure the proliferative and invasive abilities. The Kaplan-Meier method was conducted to calculate the overall survival of gastric cancer patients.

RESULTS

MiR-181d was detected to be downregulated in gastric cancer tissues and cell lines compared to the peritumoral normal tissues and normal cell line. Downregulation of miR-181d predicted poor prognosis of gastric cancer patients. Cylindromatosis gene (CYLD) was overexpressed in gastric cancer tissues, which was confirmed to be a target gene of miR-181d in gastric cancer cell line HGC-27. Moreover, miR-181d inhibited the proliferation through CYLD/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway and inhibited the invasion-mediated epithelial-mesenchymal transition (EMT) in HGC-27 cells. In addition, overexpression of miR-181d suppressed tumor growth and xenograft tumorigenesis of HGC-27 cells in vivo.

CONCLUSIONS

MiR-181d functioned as a tumor suppressor by inhibiting the proliferation via PI3K/AKT pathway in vitro and in vivo and inhibiting invasion-mediated epithelial-mesenchymal transition (EMT) by targeting CYLD in gastric cancer. The newly identified miR-181d/CYLD axis provides novel insight into the pathogenesis of gastric cancer.

MiR-100 up-regulation enhanced cell autophagy and apoptosis induced by cisplatin in osteosarcoma by targeting mTOR

Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "MiR-100 up-regulation enhanced cell autophagy and apoptosis induced by cisplatin in osteosarcoma by targeting mTOR, by Z. Yu, N. Li, K. Jiang, N. Zhang, L.-L. Yao, published in Eur Rev Med Pharmacol Sci 2018; 22 (18): 5867-5873-DOI: 10.26355/eurrev_201809_15913 -PMID: 30280766" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/15913.

Measurable residual disease (MRD) assessed by mass spectrometry (MS) in peripheral blood versus next generation sequencing (NGS) in bone marrow in multiple myeloma treated on phase II trial of KRd+ASCT

8513

Background: MRD-negativity in multiple myeloma (MM) assessed by NGS in bone marrow (BM) aspirate is associated with longer progression free survival (PFS) and overall survival. MS can detect monoclonal protein at a heightened sensitivity in peripheral blood (PB). We sought to assess the concordance of MS in PB and NGS in BM, comparing outcomes by MRD status. Methods: MRD was tested on paired PB and BM samples from transplant (ASCT)-eligible pts with newly diagnosed secretory MM who received treatment on a phase II clinical trial (NCT01816971) with KRd for 4 cycles, ASCT, KRd for 14 cycles, and lenalidomide maintenance (LM). Both NGS and MS were evaluable in 36 pts after a total of 18 cycles of KRd (C18) and in 24 pts after 1 year of LM. MS signatures were identified in pretreatment PB samples. C18 and after 1 year of LM PB samples were evaluated using both MALDI-TOF and liquid-chromatography-MS (LCMS) by the Binding Site Group. Paired MRD by NGS was performed by ClonoSEQ. 20/60 samples reached the limit of detection for 10−6 and 40/60 for 10−5. Results: There was substantial concordance between NGS and MALDI-TOF among the 60 samples ( κ= 0.667, 83% agreement) and fair concordance between NGS and LCMS ( κ= 0.348, 63% agreement). However, all 22 discordant samples (8 with NGS depth 10−6, 14 with NGS depth 10−5) were NGS−/LCMS+. 4/16 (25%) of these pts converted to NGS+, and 3/16 (19%) clinically progressed. There was stronger concordance between LCMS and NGS 10−6( κ= 0.615) than with NGS 10−5( κ= 0.375). At a median follow-up of 56 months, C18 LCMS−(n = 9) was associated with superior PFS vs all LCMS+(n = 27; p = 0.03) and independently vs NGS—/LCMS+ (n = 14; p = 0.04). There were 10 events (including 4 deaths) in the C18 LCMS+ group vs 0 in the LCMS− group. Conclusions: MRD assessment by LCMS in PB appears to reach and possibly exceed the sensitivity of MRD by NGS in BM at a depth of 10−5-10−6. LCMS positivity predicted conversion from NGS— to NGS+ in 25% of discordant cases, and LCMS negativity was a better predictor of superior PFS than MRD negativity by NGS. These observations need confirmation in larger prospective studies.

First Measurement of Λ_{c} Baryon Production in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

We report on the first measurement of the charmed baryon Λ_{c}^{±} production at midrapidity (|y|<1) in Au+Au collisions at sqrt[s_{NN}]=200  GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider. The Λ_{c}/D^{0} [denoting (Λ_{c}^{+}+Λ_{c}^{-})/(D^{0}+D[over ¯]^{0})] yield ratio is measured to be 1.08±0.16  (stat)±0.26  (sys) in the 0%-20% most central Au+Au collisions for the transverse momentum (p_{T}) range 3<p_{T}<6  GeV/c. This is significantly larger than the pythia model calculations for p+p collisions. The measured Λ_{c}/D^{0} ratio, as a function of p_{T} and collision centrality, is comparable to the baryon-to-meson ratios for light and strange hadrons in Au+Au collisions. Model calculations including coalescence hadronization for charmed baryon and meson formation reproduce the features of our measured Λ_{c}/D^{0} ratio.

Genomic origin and EGFR-TKI treatments of pulmonary adenosquamous carcinoma

BACKGROUND

Adenosquamous carcinoma (ASC) of the lung is a heterogeneous disease that is composed of both adenocarcinoma components (ACC) and squamous cell carcinoma components (SCCC). Their genomic profile, genetic origin, and clinical management remain controversial.

PATIENTS AND METHODS

Resected ASC and metastatic tumor in regional lymph nodes (LNs) were collected. The ACC and SCCC were separated by microdissection of primary tumor. The 1021 cancer-related genes were evaluated by next-generation sequencing independently in ACC and SCCC and LNs. Shared and private alterations in the two components were investigated. In addition, genomic profiles of independent cohorts of adenocarcinomas and squamous cell carcinomas were examined for comparison. We have also carried out a retrospective study of ASCs with known EGFR mutation status from 11 hospitals in China for their clinical outcomes.

RESULTS

The most frequent alterations in 28 surgically resected ASCs include EGFR (79%), TP53 (68%), MAP3K1 (14%) mutations, EGFR amplifications (32%), and MDM2 amplifications (18%). Twenty-seven patients (96%) had shared variations between ACC and SCCC, and pure SCCC metastases were not found in metastatic LNs among these patients. Only one patient with geographically separated ACC and SCCC had no shared mutations. Inter-component heterogeneity was a common genetic event of ACC and SCCC. The genomic profile of ASC was similar to that of 170 adenocarcinomas, but different from that of 62 squamous cell carcinomas. The incidence of EGFR mutations in the retrospective analysis of 517 ASCs was 51.8%. Among the 129 EGFR-positive patients who received EGFR-TKIs, the objective response rate was 56.6% and the median progression-free survival was 10.1 months (95% confidence interval: 9.0-11.2).

CONCLUSIONS

The ACC and SCCC share a monoclonal origin, a majority with genetically inter-component heterogeneity. ASC may represent a subtype of adenocarcinoma with EGFR mutation being the most common genomic anomaly and sharing similar efficacy to EGFR TKI.

[Endovascular treatment for non-thrombotic right iliac vein compression syndrome with intravascular ultrasound]

Objective: To evaluate the clinical efficacy of endovascular treatment for non-thrombotic right iliac vein compression syndrome with intravascular ultrasound. Methods: The clinical data of 40 patients with non-thrombotic right iliac vein compression syndromereceiving intravascular ultrasound-assisted balloon dilatation combined with stent implantation from January 2012 to December 2018 were retrospectively analyzed. There were 32 males and 8 females, the average age of whom was 63 (46-81) years old. The patients were classified according to the CEAP (Clinical-Etiology- Anatomy-Pathophysiology) classification: 7 cases as C3, 18 as C4, 10 as C5 and 5 as C6. All patients underwent percutaneous right femoral vein puncture, intravascular ultrasound, and balloon dilatation combined with stentimplantation in the right iliac vein lesion location. Results: The success rate of clinical operations was 100%. There were no serious complications during the perioperative period. All patients were followed up for 4-58 months. During the follow-up period, the relief rate of limb edema was 88.6% (31/35), the pain relief rate was 86.7%(13/15), and the healing rate of ulcers was 100% (6/6). After the stent implantation, the endovascular area of the compression site was significantly enlarged (34.5mm(2)± 11.1mm(2)vs129.8 mm(2)±17.2 mm(2), P<0.001). The follow-up of color Doppler and/or anterograde angiography for deep veins of lower limb with digital subtraction angiography showed that the blood flow in the stentsweres mooth in all patients. Three cases were observed that the intimal hyperplasia led to mild in-stent restenosis, no obvious in stent restenosis (>50%). The abdominal X-ray plain film showed no obvious displacement and fracture of the stents. The venous clinical severity score (VCSS) was statistically significant (13.0±2.4 vs 6.2±2.0, P<0.001). The statistical results of short-form health surver SF-36 showed that the scores of life quality in all dimensions of the affected limb were significantly improved after operation (P=0.000). Conclusion: Intravascular ultrasound-assisted balloon dilatation combined with stent implantation is not only a safe and effective treatment for non-thrombotic right iliac vein compression syndrome, but also has a good mid-term patency rate.

MiR-100 up-regulation enhanced cell autophagy and apoptosis induced by cisplatin in osteosarcoma by targeting mTOR

OBJECTIVE

Mammalian target of rapamycin (mTOR) can negatively regulate cell autophagy, while its expression and activity are associated with the pathogenesis of osteosarcoma. MicroRNA 100 (MiR-100) down-regulation is associated with the pathogenesis and chemo-sensitivity of osteosarcoma. Bioinformatics analysis revealed the targeted relationship between miR-100 and the 3'-UTR of mTOR. We investigate the role of miR-100 in affecting mTOR expression, osteosarcoma cell autophagy, and sensitivity to cisplatin.

PATIENTS AND METHODS

MiR-100, mTOR, and Beclin-1 expressions in osteosarcoma tissue and normal control were compared. The relationship between miR-100 and mTOR was verified by dual luciferase assay. MiR-100, mTOR, and Beclin-1 levels in MG-63 cells and MG-63/DDP cells were tested. Cell apoptosis was determined by using flow cytometry. Cell malignancy was evaluated by colony formation assay.

RESULTS

MiR-100 and Beclin-1 significantly declined, while mTOR significantly increased in osteosarcoma tissue compared with that of normal tissue (p<0.05). MiR-100 targeting significantly inhibited mTOR expression compared to that of untreated (p<0.05). MiR-100 expression was down-regulated and mTOR level was elevated in MG-63/DDP cells compared with MG-63 cells (p<0.05). MG-63/DDP cells exhibited reduced cell autophagy and apoptosis, and enhanced colony formation induced by DDP. MiR-100 mimic and/or small interfere mTOR (si-mTOR) significantly promoted Beclin-1 expression, cell autophagy, and cell apoptosis, while attenuated colony formation.

CONCLUSIONS

MiR-100 declined, while mTOR up-regulated in osteosarcoma tissue. MiR-100 up-regulation enhanced cell autophagy and apoptosis induced by cisplatin via targeted inhibiting of mTOR.

The Aortic Calcification Index is a risk factor associated with anastomotic leakage after anterior resection of rectal cancer

AIM

Anastomotic leakage (AL) is one of the most feared postoperative complications after anterior resection (AR) of rectal cancer. An adequate blood supply at the anastomotic site is regarded as a prerequisite for healing. We hypothesize that the Aortic Calcification Index (ACI) might reflect the severity of atherosclerosis in patients, and thereby be a risk factor for AL.

METHOD

AL was investigated retrospectively according to the definition of the International Study Group of Rectal Cancer in 423 rectal cancer patients who underwent anterior rectal resection. The ACI was measured by preoperative abdominal CT scan. The cross-section of the aorta was evenly divided into 12 sectors, the number of calcified sectors was counted as the calcification score of each slice. Lasso logistic regression and multivariate regression analysis were used to identify risk factors for AL.

RESULTS

The percentage of AL after AR was 7.8% (33/423); the mortality of patients who sustained a leak was 3.0% (1/33). Patients with a high ACI had a significantly higher percentage of AL than patients with low ACI (11.2% vs 5.6%, P = 0.04). Among patients with AL, a higher ACI was associated with greater severity of AL (the ACI of patients with grade A leakage, grade B leakage and grade C leakage was 0.5% ± 0.2%, 11.5% ± 9.2% and 24.2% ± 21.7%, respectively; P = 0.008). After risk adjustment, multivariate regression analysis showed that a higher ACI was an independent risk factor for AL (OR 2.391, P = 0.04).

CONCLUSION

A high ACI might be an important prognostic factor for AL after AR for rectal cancer. Confirmatory studies are required.

First Observation of the Directed Flow of D^{0} and D^{0}[over ¯] in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

We report the first measurement of rapidity-odd directed flow (v_{1}) for D^{0} and D^{0}[over ¯] mesons at midrapidity (|y|<0.8) in Au+Au collisions at sqrt[s_{NN}]=200  GeV using the STAR detector at the Relativistic Heavy Ion Collider. In 10-80% Au+Au collisions, the slope of the v_{1} rapidity dependence (dv_{1}/dy), averaged over D^{0} and D^{0}[over ¯] mesons, is -0.080±0.017(stat)±0.016(syst) for transverse momentum p_{T} above 1.5  GeV/c. The absolute value of D^{0} meson dv_{1}/dy is about 25 times larger than that for charged kaons, with 3.4σ significance. These data give a unique insight into the initial tilt of the produced matter, and offer constraints on the geometric and transport parameters of the hot QCD medium created in relativistic heavy-ion collisions.

Polarization of Λ (Λ[over ¯]) Hyperons along the Beam Direction in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

The Λ (Λ[over ¯]) hyperon polarization along the beam direction has been measured in Au+Au collisions at sqrt[s_{NN}]=200  GeV, for the first time in heavy-ion collisions. The polarization dependence on the hyperons' emission angle relative to the elliptic flow plane exhibits a second harmonic sine modulation, indicating a quadrupole pattern of the vorticity component along the beam direction, expected due to elliptic flow. The polarization is found to increase in more peripheral collisions, and shows no strong transverse momentum (p_{T}) dependence at p_{T} greater than 1  GeV/c. The magnitude of the signal is about 5 times smaller than those predicted by hydrodynamic and multiphase transport models; the observed phase of the emission angle dependence is also opposite to these model predictions. In contrast, the kinematic vorticity calculations in the blast-wave model tuned to reproduce particle spectra, elliptic flow, and the azimuthal dependence of the Gaussian source radii measured with the Hanbury Brown-Twiss intensity interferometry technique reproduce well the modulation phase measured in the data and capture the centrality and transverse momentum dependence of the polarization signal.

Observation of Excess J/ψ Yield at Very Low Transverse Momenta in Au+Au Collisions at sqrt[s_{NN}]=200 GeV and U+U Collisions at sqrt[s_{NN}]=193 GeV

We report on the first measurements of J/ψ production at very low transverse momentum (p_{T}<0.2  GeV/c) in hadronic Au+Au collisions at sqrt[s_{NN}]=200  GeV and U+U collisions at sqrt[s_{NN}]=193  GeV. Remarkably, the inferred nuclear modification factor of J/ψ at midrapidity in Au+Au (U+U) collisions reaches about 24 (52) for p_{T}<0.05  GeV/c in the 60%-80% collision centrality class. This noteworthy enhancement cannot be explained by hadronic production accompanied by cold and hot medium effects. In addition, the dN/dt distribution of J/ψ for the very low p_{T} range is presented for the first time. The distribution is consistent with that expected from the Au nucleus and shows a hint of interference. Comparison of the measurements to theoretical calculations of coherent production shows that the excess yield can be described reasonably well and reveals a partial disruption of coherent production in semicentral collisions, perhaps due to the violent hadronic interactions. Incorporating theoretical calculations, the results strongly suggest that the dramatic enhancement of J/ψ yield observed at extremely low p_{T} originates from coherent photon-nucleus interactions. In particular, coherently produced J/ψ's in violent hadronic collisions may provide a novel probe of the quark-gluon plasma.

The invasive tree staghorn sumac affects soil N2 -fixing bacterial communities in north China

Soil N₂ -fixing bacterial communities (SNB) can enhance soil N availability and the invasiveness of invaders. Some invaders display different degrees of invasion across different climate regions. Given that bacterial communities may change with different climate regions, it is important to understand soil micro-ecological mechanisms driving the successful invasion of invaders across different climate regions. This study performed cross-site comparisons to comprehensively analyse effects of the invasive tree staghorn sumac (Rhus typhina L.) on the structure of SNB. In north China, we selected three sites within two sampling regions (a warm temperate region and a cold temperate region). Staghorn sumac invasion did not significantly affect soil physicochemical properties and the diversity and richness of SNB. LEfSe analysis showed that numerous SNB taxa changed significantly during staghorn sumac invasion. This may be attributed in part to the selective effects of allelochemicals released by staghorn sumac via leaf litter and/or root exudates. Consequently, staghorn sumac invasion may alter the structure, rather than the diversity and richness, of SNB to facilitate its invasion process by establishing a favourable soil microenvironment in the invaded habitats. The number of species and richness of SNB under staghorn sumac invasion were significantly lower in the warm temperate region than in the cold temperate region. A possible reason for the increased diversity and richness of SNB under staghorn sumac invasion in the cold temperate region may be because staghorn sumac in the cold temperate region can provide more nutrients into the soil sub-ecosystem, presumably to support a higher diversity and richness of SNB via the nutritional requirements of SNB. The changed structure of SNB under staghorn sumac invasion, especially across different climate regions, may play an important role in its successful invasion across most regions of north China.

Azimuthal Harmonics in Small and Large Collision Systems at RHIC Top Energies

The first (v_{1}^{fluc}), second (v_{2}), and third (v_{3}) harmonic coefficients of the azimuthal particle distribution at midrapidity are extracted for charged hadrons and studied as a function of transverse momentum (p_{T}) and mean charged particle multiplicity density ⟨N_{ch}⟩ in U+U (sqrt[s_{NN}]=193  GeV), Au+Au, Cu+Au, Cu+Cu, d+Au, and p+Au collisions at sqrt[s_{NN}]=200  GeV with the STAR detector. For the same ⟨N_{ch}⟩, the v_{1}^{fluc} and v_{3} coefficients are observed to be independent of the collision system, while v_{2} exhibits such a scaling only when normalized by the initial-state eccentricity (ϵ_{2}). The data also show that ln(v_{2}/ϵ_{2}) scales linearly with ⟨N_{ch}⟩^{-1/3}. These measurements provide insight into initial-geometry fluctuations and the role of viscous hydrodynamic attenuation on v_{n} from small to large collision systems.

3-D physiomimetic extracellular matrix hydrogels provide a supportive microenvironment for rodent and human islet culture

Organ-on-a-chip platforms serve as cost-efficient testbeds for screening pharmaceutical agents, mimicking natural physiology, and studying disease. In the field of diabetes, the development of an islet-on-a-chip platform would have broad implications in understanding disease pathology and discovering potential therapies. Islet microphysiological systems are limited, however, by their poor cell survival and function in culture. A key factor that has been implicated in this decline is the disruption of islet-matrix interactions following isolation. Herein, we sought to recapitulate the in vivo peri-islet niche using decellularized extracellular matrix (ECM) hydrogels. Sourcing from porcine bladder, lung, and pancreas tissues, 3-D ECM hydrogels were generated, characterized, and validated using both rodent and human pancreatic islets. Optimized decellularization protocols resulted in hydrogels with distinctive viscoelastic properties that correlated to their matrix composition. The in situ 3-D encapsulation of human or rat islets within ECM hydrogels resulted in improved functional stability over standard culture conditions. Islet composition and morphology were also altered, with enhanced retention of islet-resident endothelial cells and the formation of cord-like structures or sprouts emerging from the islet spheroid. These supportive 3-D physiomimetic ECM hydrogels can be leveraged within microfluidic platforms for the long-term culture of islets.

Delivery of mRNA to platelets using lipid nanoparticles

Platelets are natural delivery vehicles within the blood, carrying and releasing their contents at sites of vasculature damage. Investigating the biology of platelets, and modifying them for new therapeutic uses, is limited by a lack of methods for efficiently transfecting these cells. The ability of four different classes of lipid nanoparticles (LNPs) to deliver mRNA to platelets was compared using confocal microscopy, flow cytometry and quantitative PCR. The amount of mRNA delivered, mechanism of uptake, and extent of platelet activation depended on the LNP formulation and platelet storage conditions. Cationic LNPs (cLNPs) delivered mRNA to the largest percentage of platelets but induced platelet activation. Ionizable cationic LNPs (icLNPs) delivered mRNA to fewer platelets and did not induce activation. Furthermore, mRNA delivered using icLNPs and cLNPs was stable in resting platelets and was released in platelet microparticles under specific conditions. The results demonstrate that mRNA can be delivered to platelets using cLNPs and icLNPs without impairing platelet aggregation or spreading. Optimizing the LNP formulations used here may lead to a transfection agent for platelets that allows for de novo synthesis of exogenous proteins in the future.

Low-p_{T} e^{+}e^{-} Pair Production in Au+Au Collisions at sqrt[s_{NN}]=200 GeV and U+U Collisions at sqrt[s_{NN}]=193 GeV at STAR

We report first measurements of e^{+}e^{-} pair production in the mass region 0.4<M_{ee}<2.6  GeV/c^{2} at low transverse momentum (p_{T}<0.15  GeV/c) in noncentral Au+Au collisions at sqrt[s_{NN}]=200  GeV and U+U collisions at sqrt[s_{NN}]=193  GeV. Significant enhancement factors, expressed as ratios of data over known hadronic contributions, are observed in the 40%-80% centrality of these collisions. The excess yields peak distinctly at low p_{T} with a width (sqrt[⟨p_{T}^{2}⟩]) between 40 and 60  MeV/c. The absolute cross section of the excess depends weakly on centrality, while those from a theoretical model calculation incorporating an in-medium broadened ρ spectral function and radiation from a quark gluon plasma or hadronic cocktail contributions increase dramatically with an increasing number of participant nucleons. Model calculations of photon-photon interactions generated by the initial projectile and target nuclei describe the observed excess yields but fail to reproduce the p_{T}^{2} distributions.

Beam Energy Dependence of Jet-Quenching Effects in Au+Au Collisions at sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV

We report measurements of the nuclear modification factor R_{CP} for charged hadrons as well as identified π^{+(-)}, K^{+(-)}, and p(p[over ¯]) for Au+Au collision energies of sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. We observe a clear high-p_{T} net suppression in central collisions at 62.4 GeV for charged hadrons which evolves smoothly to a large net enhancement at lower energies. This trend is driven by the evolution of the pion spectra but is also very similar for the kaon spectra. While the magnitude of the proton R_{CP} at high p_{T} does depend on the collision energy, neither the proton nor the antiproton R_{CP} at high p_{T} exhibit net suppression at any energy. A study of how the binary collision-scaled high-p_{T} yield evolves with centrality reveals a nonmonotonic shape that is consistent with the idea that jet quenching is increasing faster than the combined phenomena that lead to enhancement.