Low level laser irradiation precondition to create friendly milieu of infarcted myocardium and enhance early survival of transplanted bone marrow cells

Photobiomodulation therapy mitigates cardiovascular aging and improves survival

BACKGROUND

Photobiomodulation (PBM) therapy, a form of low-dose light therapy, has been noted to be effective in several age-associated chronic diseases such as hypertension and atherosclerosis. Here, we examined the effects of PBM therapy on age-associated cardiovascular changes in a mouse model of accelerated cardiac aging.

METHODS

Fourteen months old Adenylyl cyclase type VIII (AC8) overexpressing transgenic mice (n = 8) and their wild-type (WT) littermates (n = 8) were treated with daily exposure to Near-Infrared Light (850 nm) at 25 mW/cm2 for 2 min each weekday for a total dose of 1 Einstein (4.5 p.J/cm2 or fluence 3 J/cm2 ) and compared to untreated controls over an 8-month period. PBM therapy was administered for 3.5 months (Early Treatment period), paused, due to Covid-19 restrictions for the following 3 months, and restarted again for 1.5 months. Serial echocardiography and gait analyses were performed at monthly intervals, and serum TGF-β1 levels were assessed following sacrifice.

RESULTS

During the Early Treatment period PBM treatments: reduced the age-associated increases in left ventricular (LV) mass in both genotypes (p = 0.0003), reduced the LV end-diastolic volume (EDV) in AC8 (p = 0.04); and reduced the left atrial dimension in both genotypes (p = 0.02). PBM treatments substantially increased the LV ejection fraction (p = 0.03), reduced the aortic wall stiffness (p = 0.001), and improved gait symmetry, an index of neuro-muscular coordination (p = 0.005). The effects of PBM treatments, measured following the pause, persisted. Total TGF-β1 levels were significantly increased in circulation (serum) in AC8 following PBM treatments (p = 0.01). We observed a striking increase in cumulative survival in PBM-treated AC8 mice (100%; p = 0.01) compared to untreated AC8 mice (43%).

CONCLUSION

PBM treatment mitigated age-associated cardiovascular remodeling and reduced cardiac function, improved neuromuscular coordination, and increased longevity in an experimental animal model. These responses correlate with increased TGF-β1 in circulation. Future mechanistic and dose optimization studies are necessary to assess these anti-aging effects of PBM, and validation in future controlled human studies is required for effective clinical translation.

Photobiomodulation (800 nm Light-Emitting Diode) Treatment Promotes Bone Mesenchymal Stem Cell Proliferation Via Long Noncoding RNA MEG3-MicroRNA-217-5P Pathway

Background: Patients with osteoporosis (OP) have a high risk of bone fracture. Abnormal bone mesenchymal stem cell (BMSC) differentiation is an essential process of OP development. In recent years, photobiomodulation has been shown to effectively promote BMSC proliferation. However, the mechanism by which photobiomodulation promotes BMSC proliferation is unclear. Long noncoding RNAs (lncRNAs) are essential mediators in multiple biological processes. The lncRNA maternally expressed gene 3 (MEG3) is a novel lncRNA gene and is related to cell proliferation. Studies have indicated that MEG3 serves as a promotor in BMSC proliferation. Objective: To investigate the effects and mechanisms of 800 nm light-emitting diode (LED) photobiomodulation in BMSC proliferation. Materials and methods: The BMSCs collected from mouse tibias and femurs were irradiated by 800 nm LED for 180 sec. CCK-8 assay was used to detect the cell viability. A dual-luciferase reporter assay was used to determine IncRNA MEG3 acted as a miR-217-5p sponge. We used reverse transcription-polymerase chain reaction (RT-PCR) and western blot to detect the mRNA and protein levels of MEG3, miR-217-5p, Notch2, Hes1, Hey2. Results: In the present study, we revealed that photobiomodulation (800 nm LED) could increase the mRNA level of MEG3, and protein levels of Notch2, Hes1, and Hey2. Moreover, we also identified that upregulated MEG3 could act as a miR-217-5p sponge to activate the Notch signaling pathway. Conclusions: The current study revealed the MEG3-related mechanism of photobiomodulation treatment in OP and identified potential gene therapies for OP.

Effects of selenium levels on placental oxidative stress and inflammation during pregnancy: a prospective cohort study

BACKGROUND

Studies on the impact of Se levels in different pregnancy periods on placental function are limited.

AIM

This cohort study sought to investigate the levels of the trace element Se and to assess their effects on placental oxidative stress (OS) and mRNA expression of inflammatory genes during pregnancy.

METHODS

The study population consisted of 2519 pregnant women from the Ma'anshan birth cohort. Se levels were measured in the first and second trimesters of pregnancy and in cord blood using inductively coupled plasma-mass spectrometry (ICP-MS). Placental stress and mRNA expression of inflammatory genes were assessed using RT-PCR.

RESULTS

A statistically significant negative association was noted between Se levels in the second trimester of pregnancy and mRNA expression of placental HO-1(β = -0.009, p < .01), HIF1α (β = -0.005, p = .010), GRP78 (β = -0.011, p < .001), CRP (β = -.007, p = .033) and CD68 (β = -0.006, p = .019). A negative association was noted between Se levels in cord blood and mRNA expression of placental HO-1 (β = -0.007, p = .004), HIF1α (β = -0.006, p = .005) and GRP78 (β = -0.009, p = .004). We found that prenatal Se status was associated with placental stress and mRNA expression of inflammatory genes.

CONCLUSION

Se deficiency during pregnancy, especially in the second trimester, leads to the production of OS and an increase in inflammatory mediators, affecting the growth and development of the fetus. Monitoring of pregnant women's nutritional status is necessary to prevent nutritional imbalances and deficiencies in important micronutrients in the fetal.

Changes in Rats' Gut Microbiota Composition Caused by Induced Chronic Myocardial Infarction Lead to Depression-Like Behavior

Depression is common among patients who have chronic myocardial infarction (CMI). Despite their frequency, depression and CMI are bidirectional related conditions, each is a risk for the other, and they often co-exist, suggesting shared or interacting pathomechanisms. Accumulating data revealed the effects of gut microbiota in terms of regulating depression via the gut–brain axis. Thus, we investigated the role of gut microbial dysbiosis in CMI-induced depression-like behavior. Hierarchical cluster analysis of sucrose preference test (SPT) results was adopted to classify the CMI rats into depression-like behavior (CMI + Dep) or non-depression-like behavior (CMI + Non-Dep) phenotypes. First, 16S ribosomal RNA sequencing analysis showed both β-diversity and relative abundance of several gut bacteria significantly differed between the CMI + Dep and CMI + Non-Dep rats. Next, transplantation of fecal microbiota from CMI + Dep rats visibly altered the relative abundance of gut microbiota and also induced depression-like behavior in the antibiotics-treated pseudo-germ-free rats. In conclusion, these findings suggested that dysbiosis in gut microbial composition contributed to the onset of CMI-induced depression-like behavior and that exogenous regulation of gut microbiota composition could be a potential therapeutic strategy for CMI and related depression-like behavior.

Effectiveness of preconditioned adipose-derived mesenchymal stem cells with photobiomodulation for the treatment of diabetic foot ulcers: a systematic review

The primary goal of this systematic review article was to provide an outline of the use of diabetic autologous adipose-derived mesenchymal stem cells (DAAD-MSCs) in the treatment of wounds and ulcers in animal models and patients with diabetes mellitus (DM). The secondary goal was to present the outcomes of pretreatment of diabetic adipose-derived mesenchymal stem cells (DAD-MSCs) with probable different agents in the treatment of diabetic foot ulcers (DFUs) and wounds. In view of possible clinical applications of AD-MSC-mediated cell therapy for DFUs, it is essential to evaluate the influence of DM on AD-MSC functions. Nevertheless, there are conflicting results about the effects of DAAD-MSCs on accelerating wound healing in animals and DM patients. Multistep research of the MEDLINE, PubMed, Embase, Clinicaltrials.gov, Scopus database, and Cochrane databases was conducted for abstracts and full-text scientific papers published between 2000 and 2020. Finally, 5 articles confirmed that the usage of allogeneic or autologous AD-MSCs had encouraging outcomes on diabetic wound healing. One study reported that DM changes AD-MSC function and therapeutic potential, and one article recommended that the pretreatment of diabetic allogeneic adipose-derived mesenchymal stem cells (DAlD-MSCs) was more effective in accelerating diabetic wound healing. Recently, much work has concentrated on evolving innovative healing tactics for hastening the repair of DFUs. While DM alters the intrinsic properties of AD-MSCs and impairs their function, one animal study showed that the pretreatment of DAlD-MSCs in vitro significantly increased the function of DAlD-MSCs compared with DAlD-MSCs without any treatment. Preconditioning diabetic AD-MSCs with pretreatment agents like photobiomodulation (PBM) significantly hastened healing in delayed-healing wounds. It is suggested that further animal and human studies be conducted in order to provide more documentation. Hopefully, these outcomes will help the use of DAAD-MSCs plus PBM as a routine treatment protocol for healing severe DFUs in DM patients.

Photobiomodulation therapy preconditioning modifies nitric oxide pathway and oxidative stress in human-induced pluripotent stem cell-derived ventricular cardiomyocytes treated with doxorubicin

Doxorubicin (DOX) is an anthracycline antibiotic that exhibits high heart toxicity. Human-induced pluripotent stem cell-derived ventricular cardiomyocytes (hiPSC-vCMs) are important in vitro models for testing drug cardiotoxicity. Photobiomodulation therapy (PBMT) is a non-invasive therapy that stimulates cells growth and self-repair using light irradiation. This study aimed to investigate the in vitro effects of PBMT preconditioning on cardiotoxicity induced by DOX. HiPSC-vCMs were treated with PBMT for 500 s, followed by the addition of 2 μM DOX. LED irradiation preconditioning parameters were at 660 nm with an irradiance of 10 mW/cm², performing 5 J/cm², followed by 24-h DOX exposure (2 μM). Human iPSC-vCMs treated with 2 μM DOX or irradiated with PBMT composed the second and third groups, respectively. The control group did neither receive PBMT preconditioning nor DOX and was irradiated with a white standard lamp. Cells from all groups were collected to perform mRNA and miRNA expressions quantification. PBMT, when applied before the DOX challenge, restored the viability of hiPSC-vCMs and reduced ROS levels. Although downregulated by DOX, myocardial UCP2 mRNA expression presented marked upregulation after PBMT preconditioning. Expression of eNOS and UCP2 mRNA and NO production were decreased after DOX exposure, and PBMT preconditioning before the DOX challenge reversed these changes. Moreover, our data indicated that PBMT preconditioning lowered the miR-24 expression. Our data suggested that PBMT preconditioning ameliorated in vitro DOX-induced cardiotoxicity on transcription level, restoring NO levels and reducing oxidative stress.

Increased Myocardial Retention of Mesenchymal Stem Cells Post-MI by Pre-Conditioning Exercise Training

Stem cell (SC) therapy is a promising approach to improve post-myocardial infarction (MI) cardiac remodeling, but the proinflammatory microenvironment may lead to SC loss and, therefore, may have a negative impact on therapy. It appears that exercise training (ET) improves myocardial microenvironment for SC transplantation. Therefore, we tested the effect of ET on post-infarction retention of adipose-derived SCs (ADSCs) and its combined effects on the inflammatory microenvironment. Fischer-344 female rats were randomized to one of the following groups: Sham; sedentary coronary occlusion who did not receive ADSCs (sMI); sedentary coronary occlusion who received ADSCs; exercise coronary occlusion who received ADSCs. Rats were trained nine weeks prior to MI, followed by ADSCs transplantation. The MI led to left ventricle (LV) dilation and dysfunction, myocardial hypertrophy and fibrosis, and increased proinflammatory profile compared to Sham rats. Conversely, ADSCs transplanted rats exhibited, better morphological and functional LV parameters; inhibition of myocardial hypertrophy and fibrosis; and attenuation of proinflammatory cytokines (interleukins 1β and 10, tumor necrosis factor α, and transforming growth factor β) in the myocardium compared to sMI rats. Interestingly, ET enhanced the effect of ADSCs on interleukin 10 expression. There was a correlation between cytokine expression and myocardial ADSCs retention. The. ET enhanced the beneficial effects of ADSCs in infarcted myocardium, which was associated with higher ADSCs retention. These findings highlight the importance of ET in myocardial retention of ADSCs and attenuation of cardiac remodeling post-infarction. Cytokine analysis suggests improvement in ET-linked myocardial microenvironment based on its anti-inflammatory action.

Extracellular vesicles derived from myocardial infarction plasma inhibit BMSCs apoptosis and enhance cardiac function via AKT signaling pathway

This study aimed to investigate whether extracellular vesicles (EVs) secreted in myocardial infarction (MI) plasma could protect against apoptosis of bone marrow mesenchymal stem cells (BMSCs) following hypoxia or serum deprivation in vitro and improve cardiac function following MI in vivo. The plasma samples were taken from female rats 24 h after MI. EVs were obtained and co-cultured with BMSCs. We found that EVs could be taken up by BMSCs. Co-culturing with EVs attenuated hypoxia-induced apoptosis of BMSCs in EVs in a dose-dependent manner, which was reversed by the pharmacological inhibition of AKT signaling. Co-culturing with EVs improved transplantation efficiency and blunted MI-induced apoptosis of BMSCs in vivo. Furthermore, transplantation of BMSCs together with EVs can effectively promote the increase in capillary density both at the border and central zone of myocardium and ameliorate myocardial remodeling in MI rats. BMSCs and EVs transplantation treatment exhibited significant improvements in ejection fraction, fraction shortening, left ventricular end-diastolic dimensions, and left ventricular end-systolic dimensions, as evaluated by echocardiography four weeks after MI in rats. Finally, levels of differentiation- and apoptosis-related microRNAs expression in EVs that may mediate these effects were also identified by microarray and quantitative real-time PCR. In conclusion, the present results suggest a potential role of plasma-derived EVs in decreasing apoptosis of BMSCs by activating AKT signaling, promoting angiogenesis, ameliorating myocardial remodeling, and improving cardiac function in MI rats. EV application may be a novel option to ameliorate the therapeutic efficiency of BMSCs to improve cardiac function following MI.

LLLI promotes BMSC proliferation through circRNA_0001052/miR-124-3p

Osteoporosis (OP) is a multifactorial bone disease that occurs worldwide. The treatment of OP is still unsatisfactory. Bone mesenchymal stem cell (BMSC) differentiation is a key process in OP pathogenesis. Low-level laser irradiation (LLLI) has been reported to regulate BMSC proliferation, but the role of circRNAs in the LLLI-based promotion of BMSC proliferation remains unclear. CircRNAs are essential molecular regulators that participate in numerous biological processes and have therapeutic potential. miR-124-3p is an essential microRNA (miRNA), and its expression changes are related to BMSC proliferation ability. In the present study, gain-loss function of experiments demonstrated that circRNA_0001052 could regulate the proliferation of BMSCs by acting as a miR-124-3p sponge through the Wnt4/β-catenin pathway. The results of this study strongly suggest that circRNA_0001052 plays an essential role in BMSC proliferation in response to LLLI treatment, which is a potential therapeutic manipulation with clinical applications.

Phototherapy as a Rational Antioxidant Treatment Modality in COVID-19 Management; New Concept and Strategic Approach: Critical Review

The COVID-19 pandemic has taken the entire globe by storm. The pathogenesis of this virus has shown a cytokine storm release, which contributes to critical or severe multi-organ failure. Currently the ultimate treatment is palliative; however, many modalities have been introduced with effective or minimal outcomes. Meanwhile, enormous efforts are ongoing to produce safe vaccines and therapies. Phototherapy has a wide range of clinical applications against various maladies. This necessitates the exploration of the role of phototherapy, if any, for COVID-19. This critical review was conducted to understand COVID-19 disease and highlights the prevailing facts that link phototherapy utilisation as a potential treatment modality for SARS-CoV-2 viral infection. The results demonstrated phototherapy's efficacy in regulating cytokines and inflammatory mediators, increasing angiogenesis and enhancing healing in chronic pulmonary inflammatory diseases. In conclusion, this review answered the following research question. Which molecular and cellular mechanisms of action of phototherapy have demonstrated great potential in enhancing the immune response and reducing host-viral interaction in COVID-19 patients? Therefore, phototherapy is a promising treatment modality, which needs to be validated further for COVID-19 by robust and rigorous randomised, double blind, placebo-controlled, clinical trials to evaluate its impartial outcomes and safety.

Influence of electromagnetic waves, with maxima in the green or red range, on the morphofunctional properties of multipotent stem cells

This paper examines the effect of electromagnetic waves, with maxima in the green or red regions of the spectrum, on the morphofunctional state of multipotent mesenchymal stromal cells. The illumination regimes used in our experiments did not lead to any substantial heating of the samples; the physical parameters of the lighting were carefully monitored. When the samples were illuminated with a green light, no significant photostimulatory effect was observed. Red light, on the other hand, had an evident photostimulatory effect. It is shown that photostimulation with a red light decreases the enzymatic activities of mitochondrial dehydrogenases and enhances the viability of cells, their proliferative activity, and their ability to form bone tissue. It is also established that red light stimulates cell proliferation, while not activating the genes that increase the risk of the subsequent malignant transformation of cells or their death. This paper discusses the possible role of hydrogen peroxide in the processes examined.

Low level laser therapy (LLLT) modulates ovarian function in mature female mice

It is known that LLLT has beneficial effects on several pathological conditions including wound healing, pain and inflammation. LLLT modulates biological processes, including cell proliferation, apoptosis and angiogenesis. In the present study, we examined the effect of local application of LLLT on follicular dynamics, ovarian reserve, AMH expression, progesterone levels, apoptosis, angiogenesis, and reproductive outcome in adult mice. LLLT (200 J/cm2) increased the percentage of primary and preantral follicles, whilst decreasing the percentage of corpora lutea compared to control ovaries. LLLT-treated ovaries did not exhibit any changes regarding the number of primordial follicles. We observed a higher percentage of AMH-positive follicles (in early stages of development) in LLLT-treated ovaries compared to control ovaries. LLLT reduced the P4 concentration and the apoptosis in early antral follicles compared to control ones. LLLT caused a reduction in the endothelial cell area and an increase in the periendothelial cell area in the ovary. Additionally, LLLT was able to improve oocyte quality. Our findings suggest that local application of LLLT modulates follicular dynamics by regulating apoptosis and the vascular stability in mouse ovary. In conclusion, these data indicate that LLLT might become a novel and useful tool in the treatment of several pathologies, including female reproductive disorders.

Catalpol Promotes the Survival and VEGF Secretion of Bone Marrow-Derived Stem Cells and Their Role in Myocardial Repair After Myocardial Infarction in Rats

Bone mesenchymal stem cells (BMSCs) transplantation has been recognized as an effective method for the treatment of myocardial infarction (MI). However, its efficacy is always restricted by the low survival of transplanted BMSCs in the ischemic myocardium. The aim of this study was to investigate the effect of catalpol pre-treatment on the survival and vascular endothelial growth factor (VEGF) secretion of BMSCs under oxygen glucose deprivation (OGD) condition and their role in myocardial repair in a rat model of MI. According to our results, pre-treatment with catalpol enhanced VEGF secretion and survival of OGD-treated BMSCs. Moreover, the apoptosis of BMSCs induced by OGD was restrained by catalpol as evidenced by increased level of B-cell lymphoma-2 (Bcl-2) and decreased levels of BCL2-associated X (Bax) and cleaved caspase-3. In vivo study suggested that the survival of transplanted BMSCs was improved by catalpol pre-treatment. The myocardial fibrosis and apoptosis was further inhibited in catalpol pre-treated BMSCs group. Cardiac function detected by echocardiography was obviously improved by catalpol pre-treated BMSCs transplantation. Finally, angiogenesis and VEGF expression in the ischemic myocardium were significantly promoted in catalpol pre-treated BMSCs group. In conclusion, catalpol pre-treatment may facilitate the survival and VEGF secretion of BMSCs and improve their therapeutic effect on MI.

Exercise Training Potentiates The Cardioprotective Effects of Stem Cells Post-infarction

BACKGROUND

Preconditioning of cell recipients may exert a significant role in attenuating the hostility of the infarction milieu, thereby enhancing the efficacy of cell therapy. This study was conducted to examine whether exercise training potentiates the cardioprotective effects of adipose-derived stem cell (ADSC) transplantation following myocardial infarction (MI) in rats.

METHODS

Four groups of female Fisher-344 rats were studied: Sham; non-trained rats with MI (sMI); non-trained rats with MI submitted to ADSCs transplantation (sADSC); trained rats with MI submitted to ADSCs (tADSC). Rats were trained 9 weeks prior to MI and ADSCs transplantation. Echocardiography was applied to assess cardiac function. Myocardial performance was evaluated in vitro. Protein expression analyses were carried out by immunoblotting. Periodic acid-Schiff staining was used to analyse capillary density and apoptosis was evaluated with terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay.

RESULTS

Echocardiography performed 4 weeks after the infarction revealed attenuated scar size in the both sADSC and tADSC groups compared to the sMI group. However, fractional shortening was improved only in the tADSC group. In vitro myocardial performance was similar between the tADSC and Sham groups. The expression of phosphoSer473Akt1 and VEGF were found to be higher in the hearts of the tADSC group compared to both the sADSC and sMI groups. Histologic analysis demonstrated that tADSC rats had higher capillary density in the remote and border zones of the infarcted sites compared to the sMI rats.

CONCLUSIONS

Preconditioning with exercise induces a pro-angiogenic milieu that may potentiate the therapeutic effects of ADSCs on cardiac remodelling following MI.

Review of light parameters and photobiomodulation efficacy: dive into complexity

Photobiomodulation (PBM) therapy, previously known as low-level laser therapy, was discovered more than 50 years ago, yet there is still no agreement on the parameters and protocols for its clinical application. Some groups have recommended the use of a power density less than 100  mW/cm2 and an energy density of 4 to 10  J/cm2 at the level of the target tissue. Others recommend as much as 50  J/cm2 at the tissue surface. The wide range of parameters that can be applied (wavelength, energy, fluence, power, irradiance, pulse mode, treatment duration, and repetition) in some cases has led to contradictory results. In our review, we attempt to evaluate the range of effective and ineffective parameters in PBM. Studies in vitro with cultured cells or in vivo with different tissues were divided into those with higher numbers of mitochondria (muscle, brain, heart, nerve) or lower numbers of mitochondria (skin, tendon, cartilage). Graphs were plotted of energy density against power density. Although the results showed a high degree of variability, cells/tissues with high numbers of mitochondria tended to respond to lower doses of light than those with lower number of mitochondria. Ineffective studies in cells with high mitochondrial activity appeared to be more often due to over-dosing than to under-dosing.

Preconditioning with far-infrared irradiation enhances proliferation, cell survival, and migration of rat bone marrow-derived stem cells via CXCR4-ERK pathways

Far-infrared radiation (FIR) has been shown to exert positive effects on the cardiovascular system. However, the biological effects of FIR on bone marrow-derived stem cells (BMSCs) are not understood. In the present study, BMSCs were isolated from rat femur bone marrow and cultured in vitro. To investigate the effects of an FIR generator with an energy flux of 0.13 mW/cm² on rat BMSCs, survival of BMSCs was measured by crystal violet staining, and cell proliferation was additionally measured using Ez-Cytox cell viability, EdU, and Brd U assays. FIR preconditioning was found to significantly increase BMSC proliferation and survival against H₂O₂. The scratch and transwell migration assays showed that FIR preconditioning resulted in an increase in BMSC migration. qRT-PCR and Western blot analyses demonstrated that FIR upregulated Nanog, Sox2, c-Kit, Nkx2.5, and CXCR4 at both the mRNA and protein levels. Consistent with these observations, PD98059 (an ERK inhibitor) and AMD3100 (a CXCR4 inhibitor) prevented the activation of CXCR4/ERK and blocked the cell proliferation and migration induced by FIR. Overall, these findings provide the first evidence that FIR confers a real and significant benefit on the preconditioning of BMSCs, and might lead to novel strategies for improving BMSC therapy for cardiac ischemia.

Effect of low-level laser-treated mesenchymal stem cells on myocardial infarction

Cardiovascular disease is the leading cause of death worldwide. Although cardiac transplantation is considered the most effective therapy for end-stage cardiac diseases, it is limited by the availability of matching donors and the complications of the immune suppressive regimen used to prevent graft rejection. Application of stem cell therapy in experimental animal models was shown to reverse cardiac remodeling, attenuate cardiac fibrosis, improve heart functions, and stimulate angiogenesis. The efficacy of stem cell therapy can be amplified by low-level laser radiation. It is well established that the bio-stimulatory effect of low-level laser is influenced by the following parameters: wavelength, power density, duration, energy density, delivery time, and the type of irradiated target. In this review, we evaluate the available experimental data on treatment of myocardial infarction using low-level laser. Eligible papers were characterized as in vivo experimental studies that evaluated the use of low-level laser therapy on stem cells in order to attenuate myocardial infarction. The following descriptors were used separately and in combination: laser therapy, low-level laser, low-power laser, stem cell, and myocardial infarction. The assessed low-level laser parameters were wavelength (635-804 nm), power density (6-50 mW/cm²), duration (20-150 s), energy density (0.96-1 J/cm²), delivery time (20 min-3 weeks after myocardial infarction), and the type of irradiated target (bone marrow or in vitro-cultured bone marrow mesenchymal stem cells). The analysis focused on the cardioprotective effect of this form of therapy, the attenuation of scar tissue, and the enhancement of angiogenesis as primary targets. Other effects such as cell survival, cell differentiation, and homing are also included. Among the evaluated protocols using different parameters, the best outcome for treating myocardial infarction was achieved by treating the bone marrow by one dose of low-level laser with 804 nm wavelength and 1 J/cm² energy density within 4 h of the infarction. This approach increased stem cell survival, proliferation, and homing. It has also decreased the infarct size and cell apoptosis, leading to enhanced heart functions. These effects were stable for 6 weeks. However, more studies are still required to assess the effects of low-level laser on the genetic makeup of the cell, the nuclei, and the mitochondria of mesenchymal stromal cells (MSCs).

A Role for Photobiomodulation in the Prevention of Myocardial Ischemic Reperfusion Injury: A Systematic Review and Potential Molecular Mechanisms

Myocardial ischemia reperfusion injury is a negative pathophysiological event that may result in cardiac cell apoptosis and is a result of coronary revascularization and cardiac intervention procedures. The resulting loss of cardiomyocyte cells and the formation of scar tissue, leads to impaired heart function, a major prognostic determinant of long-term cardiac outcomes. Photobiomodulation is a novel cardiac intervention that has displayed therapeutic effects in reducing myocardial ischemia reperfusion related myocardial injury in animal models. A growing body of evidence supporting the use of photobiomodulation in myocardial infarct models has implicated multiple molecular interactions. A systematic review was conducted to identify the strength of the evidence for the therapeutic effect of photobiomodulation and to summarise the current evidence as to its mechanisms. Photobiomodulation in animal models showed consistently positive effects over a range of wavelengths and application parameters, with reductions in total infarct size (up to 76%), decreases in inflammation and scarring, and increases in tissue repair. Multiple molecular pathways were identified, including modulation of inflammatory cytokines, signalling molecules, transcription factors, enzymes and antioxidants. Current evidence regarding the use of photobiomodulation in acute and planned cardiac intervention is at an early stage but is sufficient to inform on clinical trials.

Low-Level Laser Application in the Early Myocardial Infarction Stage Has No Beneficial Role in Heart Failure

Low-level laser therapy (LLLT) has been targeted as a promising approach that can mitigate post-infarction cardiac remodeling. There is some interesting evidence showing that the beneficial role of the LLLT could persist long-term even after the end of the application, but it remains to be systematically evaluated. Therefore, the present study aimed to test the hypothesis that LLLT beneficial effects in the early post-infarction cardiac remodeling could remain in overt heart failure even with the disruption of irradiations. Female Wistar rats were subjected to the coronary occlusion to induce myocardial infarction or Sham operation. A single LLLT application was carried out after 60 s and 3 days post-coronary occlusion, respectively. Echocardiography was performed 3 days and at the end of the experiment (5 weeks) to evaluate cardiac function. After the last echocardiographic examination, LV hemodynamic evaluation was performed at baseline and on sudden afterload increases. Compared with the Sham group, infarcted rats showed increased systolic and diastolic internal diameter as well as a depressed shortening fraction of LV. The only benefit of the LLLT was a higher shortening fraction after 3 days of infarction. However, treated-LLLT rats show a lower shortening fraction in the 5th week of study when compared with Sham and non-irradiated rats. A worsening of cardiac function was confirmed in the hemodynamic analysis as evidenced by the higher LV end-diastolic pressure and lower +dP/dt and −dP/dt with five weeks of study. Cardiac functional reserve was also impaired by infarction as evidenced by an attenuated response of stroke work index and cardiac output to a sudden afterload stress, without LLLT repercussions. No significant differences were found in the myocardial expression of Akt₁/VEGF pathway. Collectively, these findings illustrate that LLLT improves LV systolic function in the early post-infarction cardiac remodeling. However, this beneficial effect may be dependent on the maintenance of phototherapy. Long-term studies with LLLT application are needed to establish whether these effects ultimately translate into improved cardiac remodeling.

Low-Level Laser Irradiation Precondition for Cardiac Regenerative Therapy

OBJECTIVE

The purpose of this article was to review the molecular mechanisms of low-level laser irradiation (LLLI) preconditioning for heart cell therapy.

BACKGROUND DATA

Stem cell transplantation appears to offer a better alternative to cardiac regenerative therapy. Previous studies have confirmed that the application of LLLI plays a positive role in regulating stem cell proliferation and in remodeling the hostile milieu of infarcted myocardium. Greater understanding of LLLI's underlying mechanisms would be helpful in translating cell transplantation therapy into the clinic.

METHODS

Studies investigating LLLI preconditioning for cardiac regenerative therapy published up to 2015 were retrieved from library sources and Pubmed databases.

RESULTS

LLLI preconditioning stimulates proliferation and differentiation of stem cells through activation of cell proliferation signaling pathways and alteration of microRNA expression. It also could stimulate paracrine secretion of stem cells and alter cardiac cytokine expression in infarcted myocardium.

CONCLUSIONS

LLLI preconditioning provides a promising approach to maximize the efficacy of cardiac cell-based therapy. Although many studies have reported possible molecular mechanisms involved in LLLI preconditioning, the exact mechanisms are still not clearly understood.

Remote Ischemic Postconditioning Ameliorates the Mesenchymal Stem Cells Engraftment in Reperfused Myocardium

Objectives

Remote Ischemic postconditioning (RIPoC) is a cardioprotective strategy for alleviating the reperfusion injury. We hypothesized that RIPoC or ischemic postconditioning (IPoC) could protect the engrafted mesenchymal stem cells (MSCs) in reperfusion myocardium.

Methods

Female Sprague-Dawley rats were subject to 30 minutes of occlusion of left anterior descending (LAD). Ischemia reperfusion (IR) received reperfusion without interruption after ischemia. RIPoC received 3 cycles of 30 seconds reperfusion and re-occlusion on the limb at the onset of reperfusion. IPoC received 3 cycles of 30 seconds reperfusion and re-occlusion on the LAD at the same time. Male MSCs were intramyocardially administered after ischemia.

Results

Compared with that in IR group, ischemic myocardium in RIPoC+IPoC group, RIPoC group and IPoC group were found to have higher anti-oxidative stress and mitochondrial function level, lower lipid peroxidation and inflammational injury level, higher level of stromal cell derived factor-1 alpha and vascular endothelium growth factor gene expression at 3 days later. By immunohistochemical examination and quantitative polymerase chain reaction, more engrafted MSCs, better cardiac function and less cardiac fibrosis in RIPoC+IPoC group, RIPoC group and IPoC group were detected at 3 weeks after delivery. There were no significant differences between RIPoC and RIPoC+IPoC group.

Conclusions

Combination therapy using intramyocardial MSCs transplantation with RIPoC enhanced transplantation efficiency and cardiac function, and reduced cardiac fibrosis. These beneficial effects were mainly attributed to hospitable milieu for engrafted cells. IPoC could not render additional effect on MSCs engraftment elicited by RIPoC.

Evaluation of the Proliferative Effects Induced by Low-Level Laser Therapy in Bone Marrow Stem Cell Culture

OBJECTIVE

The objective of this study was to evaluate the effect of laser irradiation on dog bone marrow stem cells.

BACKGROUND DATA

Low doses of low-level red laser positively affect the viability of mesenchymal stem cells, and also increase proliferation.

METHODS

Low-level laser (wavelength, 660 nm; power output, 50 mW), was applied to dog bone marrow stem cell cultures (DBMSC). The energy densities delivered varied from 1 to 12J/cm(2). The effect of the laser irradiation was evaluated on cell proliferation measured with the MTT colorimetric test, cell cycle phase, and on lipidic peroxidation (free radical production).

RESULTS

The results indicate that laser irradiation to DBMSC did not change the morphology of the cells, but significantly increased their viability and the number of cells at the G2/M phase with 6, 10, and 12 J/cm(2). On the other hand, malonaldehyde production was significantly enhanced with 8 J/cm(2).

CONCLUSIONS

The parameters used to irradiate DBMSC increased significantly proliferation without producing high levels of reactive oxygen species (ROS).

[The application of stem cells, visible and infrared light in regenerative medicine. Part 1]

OBJECTIVE

The present article was designed to overview the experimental studies of visible and infrared light irradiation of human and animal stem cells (SC) in vitro and in vivo for the evaluation of its photobiomodulatory effects. The results will be used to elaborate substantiation for the choice of the parameters of SC light irradiation and to develop recommendations for the application of this method in regenerative medicine (RM).

BACKGROUND

The clinical application of light irradiation is a matter of contrsy, in the first place due to the difficulties encountered in the rational choice of irradiation parameters. The theoretical substantiation of such choice remains a stumbling block too despite the long history of photoghromotherapy. There is thus far no reliable theoretical basis for the adequate choice of such irradiation parameters as power density, radiation dose, and exposure time. The experiences with the light application for the purpose of regenerative medicine have never been summarized.

RESULTS

The present review encompasses 78 articles selected for the basic analysis that report the studies with the use of a variety of SC types. The analysis has demonstrated that clinical investigations into the influence of light on the stem cells are still in their infancy. It was shown that the irradiation parameters need to be chosen taking into consideration the type of the stem cells. Different authors report the achievement of the maximum SC proliferation and differentiation rates at energy densities as high as 50 mW/sq.cm, small radiation doses (around 1 J/sq.cm) and exposure time (on the order of seconds).

CONCLUSION

The general conclusion for Parts 1 and II of this communication will be presented in the next issue of this journal (number 2, 2015).

Photomodulation of proliferation and differentiation of stem cells by the visible and infrared light

OBJECTIVE

The aim of this article is to review experimental studies of visible and infrared light irradiation of human and animal stem cells (SCs) in vitro and in vivo to assess photobiomodulation effects on their proliferation and differentiation.

BACKGROUND DATA

The clinical application of light irradiation remains controversial, primarily because of the complexity of the rational choice of irradiation parameters. In laboratories, the theoretical justification underlying the choice of irradiation parameters also remains a challenge.

METHODS

A systematic review was completed of original research articles that investigated the effects of light irradiation on human and animal SCs in vitro and in vivo (to June 2014). Relevant articles were sourced from PubMed and MEDLINE(®). The search terms were laser (light) therapy (irradiation), stem cells, and phototherapy, stem cells.

RESULTS

The analysis revealed the importance of cell type when choosing the cell irradiation parameters. The influence of wavelength on the SC proliferation rate seemed to be nonsignificant. The high values of increased proliferation or differentiation were obtained using high power density, low energy density, and short exposure time. SC exposure to light without inducers did not lead to their differentiation. The maximum differentiation was achieved using irradiation parameters different from the ones needed to achieve the maximum proliferation of the same cells.

CONCLUSIONS

Increased power density and reduced energy density were needed to increase the SC response. Based on the analysis, we have presented a graph of the cell response to generalized photostimulus, and introduced the concepts of "photostress" and "photoshock" to describe the stages of this response.

Influence of caspase-3 silencing on the proliferation and apoptosis of rat bone marrow mesenchymal stem cells under hypoxia

AIMS

To investigate the effects of caspase-3 silencing on the proliferation and apoptosis of rat bone marrow mesenchymal stem cells (MSCs) under hypoxia.

METHODS

Rat bone marrow MSCs were transfected with a recombinant shRNA lentivirus targeting caspase-3 expression. Protein expression of caspase-3 was measured by western blotting. Cell proliferation was measured with MTS, and the cell cycle was analyzed by flow cytometry. The apoptosis rate was measured at various time points under hypoxia. Apoptotic morphology was assessed by Hoechst 33258 staining. mRNA levels of caspase-3, Bcl-2, and Bax were measured by real-time PCR.

RESULTS

Western blotting showed that the rat MSCs were stably transfected with the shRNA targeting caspase-3 by a significant reduction of caspase-3 expression. Silencing of caspase-3 expression resulted in a significant increase of MSC proliferation (P < 0.05), an increase of cells in S-phase (52.66 ± 0.30%), and a significant decrease of apoptotic MSCs (P < 0.05). These effects exhibited a slow increase during hypoxic culture. Furthermore, caspase-3 silencing significantly down-regulated mRNA expression of caspase-3 (P < 0.01) and Bax (P < 0.01), and up-regulated Bcl-2 mRNA expression (p < 0.01), thereby increasing the ratio of Bcl-2/Bax (P < 0.05).

CONCLUSION

Caspase-3 silencing modulates the cell cycle of MSCs, promotes cell proliferation, and enhances the anti-apoptotic capacity of MSCs under hypoxia in vitro.

Pre-conditioning with low-level laser (light) therapy: light before the storm

Pre-conditioning by ischemia, hyperthermia, hypothermia, hyperbaric oxygen (and numerous other modalities) is a rapidly growing area of investigation that is used in pathological conditions where tissue damage may be expected. The damage caused by surgery, heart attack, or stroke can be mitigated by pre-treating the local or distant tissue with low levels of a stress-inducing stimulus, that can induce a protective response against subsequent major damage. Low-level laser (light) therapy (LLLT) has been used for nearly 50 years to enhance tissue healing and to relieve pain, inflammation and swelling. The photons are absorbed in cytochrome(c) oxidase (unit four in the mitochondrial respiratory chain), and this enzyme activation increases electron transport, respiration, oxygen consumption and ATP production. A complex signaling cascade is initiated leading to activation of transcription factors and up- and down-regulation of numerous genes. Recently it has become apparent that LLLT can also be effective if delivered to normal cells or tissue before the actual insult or trauma, in a pre-conditioning mode. Muscles are protected, nerves feel less pain, and LLLT can protect against a subsequent heart attack. These examples point the way to wider use of LLLT as a pre-conditioning modality to prevent pain and increase healing after surgical/medical procedures and possibly to increase athletic performance.

Effects of low level laser therapy on attachment, proliferation, and gene expression of VEGF and VEGF receptor 2 of adipocyte-derived mesenchymal stem cells cultivated under nutritional deficiency

Low-level laser therapy (LLLT) has been shown to increase the proliferation of several cell types. We evaluated the effects of LLLT on adhesion, proliferation, and gene expression of vascular endothelial growth factor (VEGF) and type 2 receptor of VEGF (VEGFR2) at mesenchymal stem cells (MSCs) from human (hMSCs) and rat (rMSCs) adipose tissues on nutritional deficiencies. A dose-response curve was performed with cells treated with laser Ga-Al-As (660 nm, 30 mW) at energy of 0.7 to 9 J. Cell adhesion and proliferation were quantified 20, 40, and 60 min after LLLT and 24, 72, and 120 h after cultivation. Gene expression was verified by RT-PCR after 2 h of LLLT. A minor nutritional support caused a significant decrease in proliferation and adhesion of hMSCs and rMSCs. However, at the lowest LLLT dose (0.7 J), we observed a higher proliferation in hMSCs at standard condition shortly after irradiation (24 h). Adhesion was higher in hMSCs cultivated in controlled conditions at higher LLLT doses (3 and 9 J), and rMSCs show a reduction in the adhesion on 1.5 to 9 J. On nutritional deprivation, a 9 J dose was shown to reduce proliferation with 24 h and adhesion to all culture times in rMSCs. VEGF and VEGFR2 were increased after LLLT in both cell types. However, hMSCs under nutritional deprivation showed higher expression of VEGF and its receptor after irradiation with other laser doses. In conclusion, LLLT on human and rat MSCs might upregulate VEGF messenger RNA (mRNA) expression and modulate cell adhesion and proliferation distinctively.

Optimization of the cardiovascular therapeutic properties of mesenchymal stromal/stem cells-taking the next step

Despite current treatment options, cardiac failure is associated with significant morbidity and mortality highlighting a compelling clinical need for novel therapeutic approaches. Based on promising pre-clinical data, stem cell therapy has been suggested as a possible therapeutic strategy. Of the candidate cell types evaluated, mesenchymal stromal/stem cells (MSCs) have been widely evaluated due to their ease of isolation and ex vivo expansion, potential allogeneic utility and capacity to promote neo-angiogenesis and endogenous cardiac repair. However, the clinical application of MSCs for mainstream cardiovascular use is currently hindered by several important limitations, including suboptimal retention and engraftment and restricted capacity for bona fide cardiomyocyte regeneration. Consequently, this has prompted intense efforts to advance the therapeutic properties of MSCs for cardiovascular disease. In this review, we consider the scope of benefit from traditional plastic adherence-isolated MSCs and the lessons learned from their conventional use in preclinical and clinical studies. Focus is then given to the evolving strategies aimed at optimizing MSC therapy, including discussion of cell-targeted techniques that encompass the preparation, pre-conditioning and manipulation of these cells ex vivo, methods to improve their delivery to the heart and innovative substrate-directed strategies to support their interaction with the host myocardium.

Transplantation of bone marrow-derived mesenchymal stem cells after regional hepatic irradiation ameliorates thioacetamide-induced liver fibrosis in rats

BACKGROUND

Recent studies have demonstrated that bone marrow-derived mesenchymal stem cells (BM-MSCs) can potentially revert liver fibrosis, but it is not known if preparative hepatic irradiation (HIR) contributes to the therapeutic effect of transplanted BM-MSCs. In this study, we investigate the effects of HIR on transplanted BM-MSCs in cirrhotic rats and the underlying mechanism by which mesenchymal stem cells (MSCs) relieve liver fibrosis.

MATERIALS AND METHODS

The BM-MSCs from male rats were labeled with CM-Dil and injected via portal vein into two groups of thioacetamide-induced cirrhotic rats, and the controls were injected with the same volume of saline. The right hemiliver of one cirrhotic rat group was irradiated (15 Gy) 4 d before transplantation. Liver function tests and histologic experiments were performed, and the liver population of BM-MSCs was estimated.

RESULTS

The transplantation of MSCs alleviated liver fibrosis and reduced expression of transforming growth factor-β1, Smad2, collagen type I, and α-SMA. HIR preconditioning promoted homing and repopulation of MSCs and resulted in better treatment outcomes.

CONCLUSIONS

HIR preconditioning enhances the effect of BM-MSCs in improving thioacetamide-induced liver fibrosis in rats by promoting their homing and repopulation. BM-MSCs may function by inhibiting transforming growth factor-β1-Smad signaling pathway in the liver.

Central zone of myocardial infarction: a neglected target area for heart cell therapy

The purpose of this study was to investigate the fate of transplanted cells in the central zone of myocardial infarction (MI), and to clarify the relationship between the injection-site impact and the efficacy of cell therapy. MI was created by coronary ligation in female rats. Three weeks later, 3-million labelled male bone marrow mesenchymal stem cells (BMSCs) were directly injected into the border (BZC group) or central zone (CZC group) of MI area. As a control, culture medium was injected into the same sites. Cell survival was evaluated by quantitative real-time polymerase chain reaction, and apoptosis was assayed with TUNEL and caspase-3 staining. Four weeks after transplantation, heart function and cardiac morphometry were evaluated by echocardiography and Masson’s Trichrome staining, respectively. Angiogenesis and myogenesis were detected by immunofluorescence staining. After cell transplantation into the border or central zone, there was no cell migration between the different zones of MI. BMSCs in the CZC group exhibited no difference in apoptotic percentage, in the long-term survival, when compared with those in the BZC group. However, they did effectively promote angiogenesis and cellular myogenic differentiation. Although cell delivery in the central zone of MI had no effect on the recovery of heart function compared with the BZC group, the retained BMSCs could still increase the scar thickness, and subsequently exhibit a trend in the reverse remodelling of ventricular dilation. Hence, we concluded that the central zone of MI should not be ignored during cell-based therapy. Multiple site injection (border+central zone) is strongly recommended during the procedure of cell transplantation.

Proliferation and differentiation potential of human adipose-derived mesenchymal stem cells isolated from elderly patients with osteoporotic fractures

Aging has less effect on adipose-derived mesenchymal stem cells (ADSCs) than on bone marrow-derived mesenchymal stem cells (BMSCs), but whether the fact holds true in stem cells from elderly patients with osteoporotic fractures is unknown. In this study, ADSCs and BMSCs of the same donor were harvested and divided into two age groups. Group A consisted of 14 young patients (36.4 ± 11.8 years old), and group B consisted of eight elderly patients (71.4 ± 3.6 years old) with osteoporotic fractures. We found that the doubling time of ADSCs from both age groups was maintained below 70 hrs, while that of BMSCs increased significantly with the number of passage. When ADSCs and BMSCs from the same patient were compared, there was a significant increase in the doubling time of BMSCs in each individual from passages 3 to 6. On osteogenic induction, the level of matrix mineralization of ADSCs from group B was comparable to that of ADSCs from group A, whereas BMSCs from group B produced least amount of mineral deposits and had a lower expression level of osteogenic genes. The p21 gene expression and senescence-associated β-galactosidase activity were lower in ADSCs compared to BMSCs, which may be partly responsible for the greater proliferation and differentiation potential of ADSCs. It is concluded that the proliferation and osteogenic differentiation of ADSCs were less affected by age and multiple passage than BMSCs, suggesting that ADSCs may become a potentially effective therapeutic option for cell-based therapy, especially in elderly patients with osteoporosis.

MicroRNA-193 pro-proliferation effects for bone mesenchymal stem cells after low-level laser irradiation treatment through inhibitor of growth family, member 5

The enhanced proliferation of mesenchymal stem cells (MSCs) can be helpful for the clinical translation of cell therapy. Low-level laser irradiation (LLLI) has been demonstrated as regulating MSC proliferation. MicroRNAs (miRNAs) are involved in various pathophysiologic processes in stem cells, but the role of miRNAs in the LLLI-based promotion of MSC proliferation remains unclear. We found that the proliferation level and cell cycle-associated genes in MSCs were increased after LLLI treatment in a time-dependent manner. Microarray assays revealed subsets of miRNAs to be differentially regulated, and these dynamic changes were confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) after LLLI. miR-193 was the most highly up-regulated miRNA, and the change in it was related with the proliferation level. Gain-loss function experiments demonstrated that miR-193 could regulate the proliferation of MSCs, including human's and rat's, but could not affect the apoptosis and differentiation level. Blockade of miR-193 repressed the MSC proliferation induced by LLLI. By qRT-PCR, we found that miR-193, in particular, regulated cyclin-dependent kinase 2 (CDK2) expression. Bioinformatic analyses and luciferase reporter assays revealed that inhibitor of growth family, member 5 (ING5) could be the best target of miR-193 to functionally regulate proliferation and CDK2 activity, and the mRNA and protein level of ING5 was regulated by miR-193. Furthermore, the ING5 inhibited by small interfering RNA (siRNA) could up-regulate the proliferation of MSCs and the expression of CDK2. Taken together, these results strongly suggest that miR-193 plays a critical part in MSC proliferation in response to LLLI stimulation, which is potentially amenable to therapeutic manipulation for clinical application.

Cardiac cell therapy: pre-conditioning effects in cell-delivery strategies

Stem-cell therapy holds great promise for the treatment of ischemic heart disease. However, the benefit of cardiac cell therapy has not yet been proven in long-term clinical trials. Poor engraftment and survival of transplanted cells is one of the major concerns for the successful application of stem cells in cardiac cell therapy. Cell and cardiac pre-conditioning are now being explored as new approaches to support cell survival and enhance the therapeutic efficacy. In this paper, we summarize the state-of-the-art methods of cell delivery and cell survival post-delivery, with a focus on the pre-conditioning approaches that have been attempted to support the survival of transplanted cells.

Vascularized atrial tissue patch cardiomyoplasty with omentopexy improves cardiac performance after myocardial infarction

BACKGROUND

The tissue-engineered cardiac patch can alleviate ventricular remodeling and improve functional recovery in experimental myocardial infarction. However, the size of the engineered patch is limited due to insufficient vascularization. This study evaluated the effects of autologous atrial tissue patch cardiomyoplasty and omentopexy in rats with myocardial infarction.

METHODS

Myocardial infarction was induced by left coronary artery ligation in Sprague-Dawley rats. Three weeks later, either a patch of left atrium (A group) or omentum (O group) or both (OA group) were placed over the infarct zone. The atrial tissue patch was harvested from the autologous left atrial appendage along its long axis. The rats in the Control group received rethoracotomy only. After 4 weeks, the survival of the transplanted atrial tissue patch, ventricular remodeling, and cardiac performance were examined.

RESULTS

After 4 weeks, surviving myocardium was only detected in the OA group, as indicated by immunolabeling of cardiac troponin-I. Compared with the Control group, only animals in the OA group showed improved heart function assessed by left ventricular ejection fraction (57.9% ± 5.8% vs 47.5% ± 4.5%, p < 0.05) and left ventricular fractional shortening (25.2% ± 3.6% vs 20.7% ± 2.0%, p < 0.05). The histologic analysis demonstrated increased scar thickness in the OA group. This was accompanied by increased angiogenesis of the border zone but decreased expression and activity of matrix metalloproteinase and endothelin-1 levels.

CONCLUSIONS

The omentopexy supported the survival of the autologous atrial tissue patch, which resulted in attenuated ventricular remodeling and restoration of heart function in rats with myocardial infarction. Our findings might represent a novel therapeutic strategy for heart failure.

Effects of low-level laser irradiation on mesenchymal stem cell proliferation: a microarray analysis

Increased proliferation after low-level laser irradiation (LLLI) has been well demonstrated in many cell types including mesenchymal stem cells (MSCs), but the exact molecular mechanisms involved remain poorly understood. The aim of this study was to investigate the change in mRNA expression in rat MSCs after LLLI and to reveal the associated molecular mechanisms. MSCs were exposed to a diode laser (635 nm) as the irradiated group. Cells undergoing the same procedure without LLLI served as the control group. Proliferation was evaluated using the MTS assay. Differences in the gene expression profiles between irradiated and control MSCs at 4 days after LLLI were analyzed using a cDNA microarray. Gene ontology and pathway analysis were used to find the key regulating genes followed by real-time PCR to validate seven representative genes from the microarray assays. This procedure identified 119 differentially expressed genes. Real-time PCR confirmed that the expression levels of v-akt murine thymoma viral oncogene homolog 1 (Akt1), the cyclin D1 gene (Ccnd1) and the phosphatidylinositol 3-kinase, catalytic alpha polypeptide gene (Pik3ca) were upregulated after LLLI, whereas those of protein tyrosine phosphatase non-receptor type 6 (Ptpn6) and serine/threonine kinase 17b (Stk17b) were downregulated. cDNA microarray analysis revealed that after LLLI the expression levels of various genes involved in cell proliferation, apoptosis and the cell cycle were affected. Five genes, including Akt1, Ptpn6, Stk17b, Ccnd1 and Pik3ca, were confirmed and the PI3K/Akt/mTOR/eIF4E pathway was identified as possibly playing an important role in mediating the effects of LLLI on the proliferation of MSCs.

Low-level laser irradiation alters cardiac cytokine expression following acute myocardial infarction: a potential mechanism for laser therapy

OBJECTIVES

Low-level laser irradiation (LLLI) has the potential of exerting cardioprotective effect following myocardial infarction (MI). The authors hypothesized that LLLI could influence the expression of cardiac cytokines and contribute to the reversal of ventricular remodeling.

BACKGROUND

LLLI regulates the expression of cytokines after tissue damage. However, little is known concerning the alteration of the cardiac cytokine expression profile after LLLI.

METHODS

MI was created by coronary ligation. The surviving rats were divided randomly into laser and control groups. 33 rats were exposed to a diode laser (635  nm, 5  mW, CW, laser, beam spot size 0.8  cm(2), 6  mW/cm(2), 150  sec, 0.8  J, 1J/cm(2)) as laser group. Another 33 rats received only coronary ligation and served as control group. 28 rats received a thoracotomy without coronary ligation (sham group). One day after laser irradiation, 5 rats from each group were sacrificed and the heart tissues were analyzed by cytokine antibody arrays. Enzyme-linked immunosorbent assay (ELISA) was performed to confirm its reliability. Two weeks after MI, cardiac function and structure were evaluated by echocardiography and histological study.

RESULTS

Cytokine antibody array indicated 4 cytokines were significantly changed after laser therapy. ELISA confirmed that granulocyte-macrophage colony stimulating factor and fractalkine were the cytokines involved in the response to therapeutic laser irradiation. However, there was no difference in cytokine release between various groups at 2 weeks after MI. Although LLLI did not improve the damaged heart function, it did reduce the infarct area expansion.

CONCLUSIONS

The antibody-based protein array technology was applied for screening the cytokine expression profile following MI, with or without laser irradiation. The expression of multiple cytokines was regulated in the acute phase after LLLI. Our results revealed a potential novel mechanism for applying laser therapy to the treatment of heart disease.

Cell survival and redistribution after transplantation into damaged myocardium

A hybrid approach to support cell survival and decrease cell escape Cell transplantation has become an attractive option for cardiac regenerative therapy. However, poor cell survival and extensive redistribution throughout the body can drastically affect the outcome and safety of cell therapy. Although various approaches have been attempted to support the survival and engraftment of implanted cells, we need to apply a new comprehensive strategy by melding the in vitro and in vivo approaches to recondition the cells and infarcted myocardium. Here we summarize our understanding of cell survival and migration after transplantation into the damaged heart.

SDF-1α inhibits hypoxia and serum deprivation-induced apoptosis in mesenchymal stem cells through PI3K/Akt and ERK1/2 signaling pathways

Bone marrow-derived mesenchymal stem cells (BMSCs) have been demonstrated to be a promising cell sources for cardiac regeneration. Poor survival rate of transplanted BMSCs in infarcted myocardium attenuated its clinical application. It's reported that stromal-derived factor-1 (SDF-1) could protect progenitor cells including endothelial progenitor cells and embryonic stem cells from apoptosis. But little is known whether SDF-1α protein has the same protective effects on BMSCs under conditions of hypoxia and serum deprivation (hypoxia/SD). In present study, we verified that SDF-1α (0.50-2.0 μg/ml) inhibited hypoxia/SD induced apoptosis of BMSCs through mitochondrial pathway. After administration of SDF-1α, the loss of mitochondrial membrane potential and cytochrome c released from mitochondria to cytosol were significantly inhibited, and caspase 3 activity also declined. Furthermore, the effect of SDF-1α on mitochondrial pathway was neutralized by using PI3K inhibitor (Wortmannin) and ERK1/2 inhibitor (U0126). Our observations suggested that SDF-1α inhibits hypoxia/SD induced BMSCs apoptosis through PI3K/Akt and ERK1/2 signaling pathways. These data also imply that the anti-apoptotic effect mediated by SDF-1α may enhance cell survival after cell transplantation.

Lasers, stem cells, and COPD

The medical use of low level laser (LLL) irradiation has been occurring for decades, primarily in the area of tissue healing and inflammatory conditions. Despite little mechanistic knowledge, the concept of a non-invasive, non-thermal intervention that has the potential to modulate regenerative processes is worthy of attention when searching for novel methods of augmenting stem cell-based therapies. Here we discuss the use of LLL irradiation as a "photoceutical" for enhancing production of stem cell growth/chemoattractant factors, stimulation of angiogenesis, and directly augmenting proliferation of stem cells. The combination of LLL together with allogeneic and autologous stem cells, as well as post-mobilization directing of stem cells will be discussed.