Treadmill exercise induces murine cardiac allograft survival and generates regulatory T cell

Graft Protective and Intercellular Immunomodulatory Effects by Adoptive Transfer of an Agonistic Anti-BTLA mAb (3C10) Induced CD4+CD25+ Regulatory T Cells in Murine Cardiac Allograft Transplant Model

BACKGROUND

We demonstrated that an agonistic anti-B and T lymphocyte attenuator antibody (3C10) prolonged cardiac survival by inducing regulatory T cells (Treg). However, the mechanisms of immune tolerance in the recipients remained unclear. In this study, we investigated the graft-protective and intercellular immunomodulatory effects of adoptive transfer (AT) of 3C10-induced Tregs in a murine cardiac allograft transplant model.

METHODS

Thirty days after transplantation of a C57BL/6 heart into the primary 3C10-treated CBA recipients, splenic CD4+CD25+ cells from these recipients (3C10/AT group) or naïve CBA mice (no-treatment group) were adoptively transferred into secondary CBA recipients with a C57BL/6 heart. To confirm the requirement for 3C10-induced Tregs, we administered an anti-interleukin-2 receptor alpha antibody (PC-61) to secondary CBA recipients. Additionally, histologic and fluorescent staining, cell proliferation analysis, flow cytometry, and donor-specific antibody (DSA) measurements were performed.

RESULTS

3C10/AT-treated CBA recipients resulted in significantly prolonged allograft survival (median survival time [MST], >50 days). Allografts displayed prolonged function with preservation of vessel structure by maintaining high numbers of splenic CD4+CD25+Foxp3+ Treg and intramyocardial CD4+Foxp3+ cells. DSA levels were suppressed in 3C10/AT-treated CBA recipients. Moreover, PC-61 administration resulted in a shorter MSTs of cardiac allograft survivals, a detrimental increase in DSA production, and enhanced expression of programmed cell death (PD)-1.

CONCLUSION

AT of 3C10-induced Tregs may be a promising graft-protective strategy to prolong allograft survival and suppress DSA production, driven by the promotion of splenic and graft-infiltrating Tregs and collaboration with PD-1+ T cells and Treg.

Regular exercise and branched-chain amino acids prevent ischemic acute kidney injury-related muscle wasting in mice

Acute kidney injury (AKI) causes glucose and protein metabolism abnormalities that result in muscle wasting, thereby affecting the long-term prognosis of critical illness survivors. Here, we examined whether early intervention with treadmill exercise and branched-chain amino acids (BCAA) can prevent AKI-related muscle wasting and reduced physical performance in mice. Unilateral 15 min ischemia-reperfusion injury was induced in contralateral nephrectomized mice, and muscle histological and physiological changes were assessed and compared with those of pair-fed control mice, since AKI causes severe anorexia. Mice exercised for 30 min each day and received oral BCAA for 7 days after AKI insult. By day 7, ischemic AKI significantly decreased wet weight, myofiber cross-sectional area, and central mitochondrial volume density of the anterior tibialis muscle, and significantly reduced maximal exercise time. Regular exercise and BCAA prevented AKI-related muscle wasting and low physical performance by suppressing myostatin and atrogin-1 mRNA upregulation, and restoring reduced phosphorylated Akt and PGC-1α mRNA expression in the muscle. Ischemic AKI induces muscle wasting by accelerating muscle protein degradation and reducing protein synthesis; however, we found that regular exercise and BCAA prevented AKI-related muscle wasting without worsening kidney damage, suggesting that early rehabilitation with nutritional support could prevent AKI-related muscle wasting.

A systematic comparison of exercise training protocols on animal models of cardiovascular capacity

Cardiovascular disease (CVD) is a major global cause of mortality, which has prompted numerous studies seeking to reduce the risk of heart failure and sudden cardiac death. While regular physical activity is known to improve CVD associated morbidity and mortality, the optimal duration, frequency, and intensity of exercise remains unclear. To address this uncertainty, various animal models have been used to study the cardioprotective effects of exercise and related molecular mechanism such as the mice training models significantly decrease size of myocardial infarct by affecting Kir6.1, VSMC sarc-K_ATP channels, and pulmonary eNOS. Although these findings cement the importance of animal models in studying exercise induced cardioprotection, the vast assortment of exercise protocols makes comparison across studies difficult. To address this issue, we review and break down the existent exercise models into categories based on exercise modality, intensity, frequency, and duration. The timing of sample collection is also compared and sorted into four distinct phases: pre-exercise (Phase I), mid-exercise (Phase II), exercise recovery (Phase III), and post-exercise (Phase IV). Finally, because the life-span of animals so are limited, small changes in animal exercise duration can corresponded to untenable amounts of human exercise. To address this limitation, we introduce the Life-Span Relative Exercise Time (RET_{life span}) as a method of accurately defining short-term, medium-term and long-term exercise relative to the animal's life expectancy. Systematic organization of existent protocols and this new system of defining exercise duration will allow for a more solid framework from which researchers can extrapolate animal model data to clinical application.

Graft protective effect and induction of CD4+Foxp3+ cell by Thrombomodulin on allograft arteriosclerosis in mice

Background

Thrombomodulin (TM) is a promising therapeutic natural anti-coagulant, which exerts the effects to control disseminated intravascular coagulation. However, little is known whether TM on micro-vessels could play an important role in the regulation of intimal hyperplasia. We investigated the vessel-protective effect of TM in the survival of fully major histocompatibility complex (MHC)-mismatched murine cardiac allograft transplantation.

Methods

CBA recipients transplanted with a C57BL/6 heart received intraperitoneal administration of normal saline or 0.2, 2.0, and 20.0 μg/day of TM for 7 days (n = 5, 7, 11, and 11, respectively). Immunohistochemical and fluorescent staining studies were performed to determine whether CD4⁺Foxp3⁺ regulatory T cell were generated at 2 and 4 weeks after grafting. Morphometric analysis for neointimal formation in the coronary arteries of the transplanted allograft was conducted at 2 and 4 weeks after grafting.

Results

Untreated CBA recipients rejected C57BL/6 cardiac grafts acutely (median survival time [MST], 7 days). CBA recipients exposed with the above doses had significantly prolonged allograft survival (MSTs, 17, 24 and 50 days, respectively). Morphometric assessment showed that intimal hyperplasia was clearly suppressed in the left and right coronary arteries or allografts from TM-exposed recipients 2 and 4 weeks. Immunohistochemical studies at 2 weeks showed more CD4⁺Foxp3⁺ cells and lower myocardial damage in the allografts from TM-exposed recipients. Notably, fluorescent staining studies demonstrated that TM-exposed recipients 4 weeks post-engraftment had strong aggregation of CD4⁺Foxp3⁺ cells in the intima of the coronary arteries of the cardiac allografts.

Conclusions

TM may prolong the survival of fully MHC-mismatched cardiac allografts through suppressing intimal hyperplasia and inducing the accumulation of regulatory CD4⁺Foxp3⁺ cells within coronary arteries.

Rikkunshito (TJ-43) Improved Reduction of Food Intake in a Murine Cardiac Transplantation Model

Rikkunshito (TJ-43), an eight-component traditional Japanese herbal medicine, has been used in clinics for gastritis, vomiting, and appetite loss. We investigated the effects of TJ-43 on the amelioration of appetite loss in the surgical-exposed model of murine cardiac allograft transplantation. CBA mice underwent transplantation of a CBA (syngeneic group) or C57BL/6 heart (allogeneic group) and received oral administration of 2 g/kg/d of TJ-43 from the day of transplantation until 7 days afterward. The amount of food intake (FI) and weight change after operation were recorded from 1 to 28 postoperative days. The allogeneic group had less average amounts of FI for 1 week compared with the syngeneic group (FI was 1.90 ± 0.43 g and 2.66 ± 0.46 g, respectively). Average FIs between the syngeneic and allogeneic groups with TJ-43 for 1 week were 2.36 ± 0.44 g and 2.30 ± 0.13 g, respectively, and those with distilled water were 2.66 ± 0.46 g and 1.90 ± 0.43 g, respectively, suggesting that exposure with TJ-43 tended to ameliorate the reduction of FI. Similarly, the effect on the amelioration of average FI in syngeneic and allogeneic groups exposed for 2 weeks was confirmed. However, exposure to with TJ-43 had no effects on FI after 4 weeks. TJ-43 could prevent reduction of average FI induced by the surgical-exposed model of murine cardiac allograft transplantation.

Induction of Regulatory CD4+ Cells and Prolongation of Fully Major Histocompatibility Complex Mismatched Murine Cardiac Allograft by Shigyakusan

Shigyakusan (also known as Tsumura Japan [TJ]-35) is composed of peony, bitter orange, licorice, and Bupleuri radix is used for cholecystitis and gastritis as an anti-inflammatory agent. We investigated the effect of TJ-35 on alloimmune response in a murine heart transplantation model. CBA mice that underwent transplantation of a C57BL/6 (B6) heart were assigned to four groups: no treatment, TJ-35-exposed, each component-exposed, or each component missing-exposed. The four groups above each received oral administration of TJ-35, each component, or TJ-35 with each component missing from the day of transplantation until 7 days, respectively. Untreated CBA recipients rejected B6 cardiac grafts acutely (median survival time [MST], 7 days). TJ-35-exposed CBA recipients had significantly prolonged B6 allograft survival (MST, 20.5 days). However, MSTs of CBA recipients that had been administered each component and TJ-35 with each component missing did not reach that of TJ-35-exposed recipients. Adoptive transfer of CD4⁺ splenocytes from TJ-35-exposed primary allograft recipients resulted in significant prolonged allograft survival in naïve secondary recipients (MST, 63 days). Flow cytometry studies showed that the percentage of CD4⁺CD25⁺Foxp3⁺ cell population was increased in TJ-35-exposed CBA recipients. In conclusion, TJ-35-induced prolongation of fully allogeneic cardiac allografts and may generate regulatory CD4⁺CD25⁺Foxp3⁺ cells in our model. The effect seemed to require all components of TJ-35.

Yogurt Feeding Induced the Prolongation of Fully Major Histocompatibility Complex-Mismatched Murine Cardiac Graft Survival by Induction of CD4+Foxp3+ Cells

Yogurt is a nutrient-rich food and the beneficial effects of yogurt on both health and immunomodulatory effects are well documented. In this pilot study, we investigated the effects of commercially produced yogurt R-1 on alloimmune responses in a murine cardiac transplantation model. The R-1 is produced by Meiji Co., Ltd., and contains live and active lactic acid bacteria (lactobacillus bulgaricus OLL1073R-1) mainly. CBA (H2^k) mice underwent transplantation of a C57BL/6 (H2^b; B6) heart and received oral administration of 1 mL, 0.1 mL, and 0.01 mL of R-1 from the day of transplantation until 7 days afterward. Additionally, we prepared one group of CBA recipients given 1 mL of R-1 sterilized by microwave for 7 days. Histological and immunohistochemical studies were performed. Naïve CBA mice rejected B6 cardiac graft acutely (median survival time [MST]: 7 days). CBA recipients given of 1 mL of R-1 had significantly prolonged B6 allograft survival (MST, 27 days). However, other doses of 0.1 mL and 0.01 mL of R-1 did not prolonged allograft survival (MSTs, 9 days and 8.5 days, respectively). Also, CBA recipients administered microwaved R-1 had no prolongation of B6 allograft (MST, 9 days). Histological and immunohistochemical studies showed the cardiac allograft from R-1-exposed CBA recipients had preserved graft and vessel structure and the number of infiltrated CD4⁺, CD8⁺, and Foxp3⁺ cells in R-1-exposed CBA recipients increased, respectively. In conclusion, our findings imply that yogurt containing active lactic acid bacteria could change alloimmune responses partially and induce the prolongation of cardiac allograft survival via CD4⁺Foxp3⁺ regulatory cells.

Lifelong training improves anti-inflammatory environment and maintains the number of regulatory T cells in masters athletes

PURPOSE

The purpose of this study was to quantify and characterize peripheral blood regulatory T cells (Tregs), as well as the IL-10 plasma concentration, in Masters athletes at rest and after an acute exhaustive exercise test.

METHODS

Eighteen Masters athletes (self-reported training: 24.6 ± 1.83 years; 10.27 ± 0.24 months and 5.45 ± 0.42 h/week per each month trained) and an age-matched control group of ten subjects (that never took part in regular physical training) volunteered for this study. All subjects performed an incremental test to exhaustion on a cycle ergometer. Blood samples were obtained before (Pre), 10 min into recovery (Post), and 1 h after the test (1 h).

RESULTS

Absolute numbers of Tregs were similar in both groups at rest. Acute exercise induced a significant increase in absolute numbers of Tregs at Post (0.049 ± 0.021 to 0.056 ± 0.024 × 10⁹/L, P = 0.029 for Masters; 0.048 ± 0.017 to 0.058 ± 0.020 × 10⁹/L, P = 0.037 for control) in both groups. Treg mRNA expression for FoxP3, IL-10, and TGF-β in sorted Tregs was similar throughout the trials in both groups. Masters athletes showed a higher percentage of subjects expressing the FoxP3 (100% for Masters vs. 78% for Controls, P = 0.038) and TGF-β (89% for Masters vs. 56% for Controls, P = 0.002) after exercise and a higher plasma IL-10 concentration (15.390 ± 7.032 for Masters vs. 2.411 ± 1.117 for control P = 0.001, ES = 2.57) at all timepoints. KLRG1 expression in Tregs was unchanged.

CONCLUSION

Our findings showed that Masters athletes have elevated anti-inflammatory markers and maintain the number of Tregs, and may be an adaptive response to lifelong training.

Effects of exercise-based cardiac rehabilitation in patients after percutaneous coronary intervention: A meta-analysis of randomized controlled trials

In this study, we assessed the effect of rehabilitation exercise after percutaneous coronary intervention (PCI) in patients with coronary heart disease (CHD). We performed a meta-analysis to determine the effects of exercise in patients after PCI. The Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, the Embase database, China National Knowledge Internet (CNKI), China Biology Medicine (CBM), and the Wanfang Database were searched for randomized controlled trials (RCTs). The key words used for the searches were PCI, exercise, walking, jogging, Tai Chi, and yoga. Six studies with 682 patients met our inclusion criteria; we chose the primary endpoint events of cardiac death, recurrence of myocardial infarction (MI), repeated PCI, coronary artery bypass grafting (CABG), and restenosis, and the secondary endpoint measures included recurrent angina, treadmill exercise (total exercise time, ST-segment decline, angina, and maximum exercise tolerance). The results showed that exercise was not clearly associated with reductions in cardiac death, recurrence of MI, repeated PCI, CABG, or restenosis. However, the exercise group exhibited greater improvements in recurrent angina, total exercise time, ST-segment decline, angina, and maximum exercise tolerance than did the control group. Future studies need to expand the sample size and improve the quality of reporting of RCTs.

Graded Maximal Exercise Testing to Assess Mouse Cardio-Metabolic Phenotypes

Functional assessments of cardiovascular fitness (CVF) are needed to establish animal models of dysfunction, test the effects of novel therapeutics, and establish the cardio-metabolic phenotype of mice. In humans, the graded maximal exercise test (GXT) is a standardized diagnostic for assessing CVF and mortality risk. These tests, which consist of concurrent staged increases in running speed and inclination, provide diagnostic cardio-metabolic parameters, such as, VO_2max, anaerobic threshold, and metabolic crossover. Unlike the human-GXT, published mouse treadmill tests have set, not staged, increases in inclination as speed progress until exhaustion (PXT). Additionally, they often lack multiple cardio-metabolic parameters. Here, we developed a mouse-GXT with the intent of improving mouse-exercise testing sensitivity and developing translatable parameters to assess CVF in healthy and dysfunctional mice. The mouse-GXT, like the human-GXT, incorporated staged increases in inclination, speed, and intensity; and, was designed by considering imitations of the PXT and differences between human and mouse physiology. The mouse-GXT and PXTs were both tested in healthy mice (C57BL/6J, FVBN/J) to determine their ability to identify cardio-metabolic parameters (anaerobic threshold, VO_2max, metabolic crossover) observed in human-GXTs. Next, theses assays were tested on established diet-induced (obese-C57BL/6J) and genetic (cardiac isoform Casq2^-/-) models of cardiovascular dysfunction. Results showed that both tests reported VO_2max and provided reproducible data about performance. Only the mouse-GXT reproducibly identified anaerobic threshold, metabolic crossover, and detected impaired CVF in dysfunctional models. Our findings demonstrated that the mouse-GXT is a sensitive, non-invasive, and cost-effective method for assessing CVF in mice. This new test can be used as a functional assessment to determine the cardio-metabolic phenotype of various animal models or the effects of novel therapeutics.