Improvements of the Surgical Technique on the Established Mouse Model of Orthotopic Single Lung Transplantation

Background

A wide range of knockout and transgenic murine models for the study of nonimmune and immune mechanisms in lung transplants are available nowadays, but the microsurgical techniques are difficult to learn. We describe methods to simplify techniques and facilitate learning.

Methods

Traditional procedures were implemented to perform lung transplants in 30 cases (group 1). Improved techniques which included cuff without tail, broadening of the cuff diameter for bronchus, establishment of one tunnel between three structures, innovative technology of the vascular anastomosis and placement of the chest tube post-operation were used to perform lung transplants in 30 cases (group 2).

Results

The improved techniques considerably shorten operative times (96.75±6.16 min and 85.32±6.98 min in groups 1 and 2, respectively). The survival rates in the recipient animals were 86.7% and 96.7% in groups 1 and 2, respectively. Chest X-rays and macroscopic changes of transplanted recipients showed that grafts were well inflated on postoperative day 30. There was no significant difference of the arterial oxygen tension (PaO₂) between two groups (115.9±7.11 mm Hg and 116.3±6.87 mm Hg in groups 1 and 2, respectively). Histologically, no lung injury was seen in grafts.

Conclusions

We described the modified procedures of orthotopic left lung transplants in mice, which could shorten operative time and increase survival rate.     

Association between Telomere Length and Type 2 Diabetes Mellitus: A Meta-Analysis

Background

Several epidemiological studies have examined the association between shortened telomere length and type 2 diabetes mellitus (T2DM), while the results remained conflicting. We conducted a meta-analysis to derive a more precise estimation of the relationship between them.

Methods

We systematically reviewed the databases of PubMed, EMBASE, and Web of Science for all studies on the association between telomere length and T2DM. We conducted this study assessed by STATA 11.0. Data were summarized using random-effects or fixed-effects meta-analysis. The heterogeneity and publication bias among studies were examined by using χ²-based Q statistic test and Egger’s test, respectively.

Results

Nine cohorts consisting of 5759 cases and 6518 controls were selected into the meta-analysis. The results indicated that shortened telomere length was significantly associated with T2DM risk (OR: 1.291; 95% CI: 1.112, 1.498; P<0.001) with heterogeneity (I² = 71.6%). When three cohorts responsible for the heterogeneity were excluded, the pooled OR for the remaining cohorts indicated a significant association between shortened telomere length and T2DM (OR: 1.117; 95% CI: 1.002, 1.246; P = 0.045) without heterogeneity.

Conclusion

We found a statistically significant association between shortened telomere length and T2DM.     

Barcoding Poplars (Populus L.) from Western China

Background

Populus is an ecologically and economically important genus of trees, but distinguishing between wild species is relatively difficult due to extensive interspecific hybridization and introgression, and the high level of intraspecific morphological variation. The DNA barcoding approach is a potential solution to this problem.

Methodology/Principal Findings

Here, we tested the discrimination power of five chloroplast barcodes and one nuclear barcode (ITS) among 95 trees that represent 21 Populus species from western China. Among all single barcode candidates, the discrimination power is highest for the nuclear ITS, progressively lower for chloroplast barcodes matK (M), trnG-psbK (G) and psbK-psbI (P), and trnH-psbA (H) and rbcL (R); the discrimination efficiency of the nuclear ITS (I) is also higher than any two-, three-, or even the five-locus combination of chloroplast barcodes. Among the five combinations of a single chloroplast barcode plus the nuclear ITS, H+I and P+I differentiated the highest and lowest portion of species, respectively. The highest discrimination rate for the barcodes or barcode combinations examined here is 55.0% (H+I), and usually discrimination failures occurred among species from sympatric or parapatric areas.

Conclusions/Significance

In this case study, we showed that when discriminating Populus species from western China, the nuclear ITS region represents a more promising barcode than any maternally inherited chloroplast region or combination of chloroplast regions. Meanwhile, combining the ITS region with chloroplast regions may improve the barcoding success rate and assist in detecting recent interspecific hybridizations. Failure to discriminate among several groups of Populus species from sympatric or parapatric areas may have been the result of incomplete lineage sorting, frequent interspecific hybridizations and introgressions. We agree with a previous proposal for constructing a tiered barcoding system in plants, especially for taxonomic groups that have complex evolutionary histories (e.g. Populus).     

Homocysteine Restricts Copper Availability Leading to Suppression of Cytochrome C Oxidase Activity in Phenylephrine-Treated Cardiomyocytes

Cardiomyocyte hypertrophy induced by phenylephrine (PE) is accompanied by suppression of cytochrome c oxidase (CCO) activity, and copper (Cu) supplementation restores CCO activity and reverses the hypertrophy. The present study was aimed to understand the mechanism of PE-induced decrease in CCO activity. Primary cultures of neonatal rat cardiomyocytes were treated with PE at a final concentration of l00 µM in cultures for 72 h to induce cell hypertrophy. The CCO activity was determined by enzymatic assay and changes in CCO subunit COX-IV as well as copper chaperones for CCO (COX17, SCO2, and COX11) were determined by Western blotting. PE treatment increased both intracellular and extracellular homocysteine concentrations and decreased intracellular Cu concentrations. Studies in vitro found that homocysteine and Cu form complexes. Inhibition of the intracellular homocysteine synthesis in the PE-treated cardiomyocytes prevented the increase in the extracellular homocysteine concentration, retained the intracellular Cu concentration, and preserved the CCO activity. PE treatment decreased protein concentrations of the COX-IV, and the Cu chaperones COX17, COX11, and SCO2. These PE effects were prevented by either inhibition of the intracellular homocysteine synthesis or Cu supplementation. Therefore, PE-induced elevation of homocysteine restricts Cu availability through its interaction with Cu and suppression of Cu chaperones, leading to the decrease in CCO enzyme activity.     

Efficacy and Tolerability of the Fixed Combinations Latanoprost/Timolol versus Dorzolamide/Timolol in Patients with Elevated Intraocular Pressure: A Meta-Analysis of Randomized Controlled Trials

Objective

To evaluate the efficacy and tolerability of the fixed combination of Latanoprost/Timolol versus Dorzolamide/Timolol in the treatment of patients with elevated intraocular pressure (IOP).

Methods

A comprehensive literature meta-analysis was performed according to the Cochrane Collaboration methodology to identify randomized clinical trials comparing latanoprost/timolol FC (FCLT) with dorzolamide/timolol (FCDT) in patients with elevated IOP. The efficacy estimates were measured by the weight mean difference (WMD) for the IOP reduction (IOPR) from baseline to end point, including the diurnal mean IOPR, 8 AM IOPR, 12 PM IOPR, and 4 PM IOPR. The tolerability estimates were measured by RR for adverse events. All outcomes were reported with a 95% confidence interval (CI). The data were synthesized by Stata 12.0 SE for Windows.

Results

Eight studies involving 841 patients (841 eyes) were included in the meta-analysis. With a WMD of IOPR in the diurnal mean of 0.16 mmHg (95% CI, -0.31 to 0.63), the FCLT was as effective as FCDT in lowering IOP in patients with elevated IOP (P = 0.51). The WMDs of IOPR were 0.58 mmHg (95% CI: -0.002 to 1.17) at 8 AM, -0.07 mmHg (95% CI: -0.50 to 0.36) at 12 PM, and 0.41 mmHg (95% CI: -0.18 to 1.00) at 4 PM, and there were no significant difference between FCLT and FCDT. FCLT was associated with a significantly lower incidence of eye pain, bitter taste, and irritation/stinging than FCDT, with pooled RRs of 0.34 (95% CI: 0.14 to 0.82), 0.06 (95% CI:0.008 to 0.42), and 0.35 (95% CI: 0.14 to 0.85), respectively.

Conclusion

FCLT was associated with equivalent efficacy in IOP lowering comparing with FCDT. However, FCLT was better tolerated than FCDT.     

Bone Marrow Deficiency of MCPIP1 Results in Severe Multi-Organ Inflammation but Diminishes Atherogenesis in Hyperlipidemic Mice

Objective

MCPIP1 is a newly identified protein that profoundly impacts immunity and inflammation. We aim to test if MCPIP1 deficiency in hematopoietic cells results in systemic inflammation and accelerates atherogenesis in mice.

Approach and Results

After lethally irradiated, LDLR^−/− mice were transplanted with bone marrow cells from either wild-type or MCPIP1^−/− mice. These chimeric mice were fed a western-type diet for 7 weeks. We found that bone marrow MCPIP1^−/− mice displayed a phenotype similar to that of whole body MCPIP1^−/− mice, with severe systemic and multi-organ inflammation. However, MCPIP1^−/− bone marrow recipients developed >10-fold less atherosclerotic lesions in the proximal aorta than WT bone marrow recipients, and essentially no lesions in en face aorta. The diminishment in atherosclerosis in bone marrow MCPIP1^−/− mice may be partially attributed to the slight decrease in their plasma lipids. Flow cytometric analysis of splenocytes showed that bone marrow MCPIP1^−/− mice contained reduced numbers of T cells and B cells, but increased numbers of regulatory T cells, Th17 cells, CD11b+/Gr1+ cells and CD11b+/Ly6C^low cells. This overall anti-atherogenic leukocyte profile may also contribute to the reduced atherogenesis. We also examined the cholesterol efflux capability of MCPIP1 deficient macrophages, and found that MCPIP1deficiency increased cholesterol efflux to apoAI and HDL, due to increased protein levels of ABCA1 and ABCG1.

Conclusions

Hematopoietic deficiency of MCPIP1 resulted in severe systemic and multi-organ inflammation but paradoxically diminished atherogenesis in mice. The reduced atheroegensis may be explained by the decreased plasma cholesterol levels, the anti-atherogenic leukocyte profile, as well as enhanced cholesterol efflux capability. This study suggests that, while atherosclerosis is a chronic inflammatory disease, the mechanisms underlying atherogenesis-associated inflammation in arterial wall versus the inflammation in solid organs may be substantially different.     

Highlighting a π–π interaction: a protein modeling and molecular dynamics simulation study on Anopheles gambiae glutathione S-transferase 1-2

Cytosolic insect theta class glutathione S-transferases (GSTs) have not been studied completely and their physiological roles are unknown. A detailed understanding of Anopheles gambiae GST (Aggst1-2) requires an accurate structure, which has not yet been determined. A high quality model structure of Aggst1-2 was constructed using homology modeling and the ligand–protein complex was obtained by the docking method. Molecular dynamics (MD) simulations were carried out to study conformational changes and to calculate binding free energy. The results of MD simulation indicate that Aggst1-2 undergoes small conformational changes after ligands dock to the protein, which facilitate the catalytic reaction. An essential hydrogen bond was found between the sulfur atom of glutathione (GSH) and the hydrogen atom of hydroxyl group in Ser9, which was in good agreement with experimental data. A π–π interaction between Phe204 and CDNB ligand was also found. This interaction seems to be important in stabilization of the ligand. Further study of binding free energy decomposition revealed a van der Waals interaction between two ligands that may play a key role in nucleophilic addition reaction. This work will be a good starting point for further determination of the biological role of cytosolic insect theta class GSTs and will aid the design of structure-based inhibitors.