Role of low-level laser therapy on the cardiac remodeling after myocardial infarction: A systematic review of experimental studies

Beneficial Effects of Exercise on Hypertension-Induced Cardiac Hypertrophy in Adolescents and Young Adults

PURPOSE OF REVIEW

Hypertension-induced cardiac hypertrophy is widely known as a major risk factor for increased cardiovascular morbidity and mortality. Although exercise is proven to exert overall beneficial effects on hypertension and hypertension-induced cardiac hypertrophy, there are some concerns among providers about potential adverse effects induced by intense exercise, especially in hypertensive athletes. We will overview the underlying mechanisms of physiological and pathological hypertrophy and delineate the beneficial effects of exercise in young people with hypertension and consequent hypertrophy.

RECENT FINDINGS

Multiple studies have demonstrated that exercise training, both endurance and resistance types, reduces blood pressure and ameliorates hypertrophy in hypertensives, but certain precautions are required for hypertensive athletes when allowing competitive sports: Elevated blood pressure should be controlled before allowing them to participate in high-intensity exercise. Non-vigorous and recreational exercise are always recommended to promote cardiovascular health. Exercise-induced cardiac adaptation is a benign and favorable response that reverses or attenuates pathological cardiovascular remodeling induced by persistent hypertension. Exercise is the most effective nonpharmacological treatment for hypertensive individuals. Distinction between recreational-level exercise and competitive sports should be recognized by medical providers when allowing sports participation for adolescents and young adults.

Examining the impact of varying low-level laser dose on cardiac failure

Low-level laser therapy (LLLT) has been targeted as a promising tool that can mitigate post-infarction cardiac remodeling. However, there is no gold standard energy delivered to the heart and few studies have evaluated the impact of LLLT on cardiac performance. This study evaluated effects of repeated LLLT applications with different energies delivered to the infarcted myocardium. Echocardiography and hemodynamic measurements were applied to evaluate left ventricular (LV) performance in rats with large infarcts. ELISA, Western blot and biochemical assays were used to assess LV inflammation and oxidative stress. An 830-nm Laser Photon III semiconductor aluminum gallium arsenide diode (DMC, São Carlos, SP, Brazil) was applied transthoracically three times a week for 4 weeks based on the energy (i.e., 10J, 20J, and 40J; respectively). LLLT on 10J and 20J had a similar action in attenuating pulmonary congestion and myocardial fibrosis. Moreover, 10J and 20J attenuated LV end-diastolic pressure and improved +dP/dt and -dP/dt. All LLLT groups had lower levels of inflammatory mediators, but only the 10J group had normalized oxidative stress. All LLLT doses improved superoxide dismutase levels; however, only the 20J group showed a high content of the catalase. There was a lower level of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a in the infarcted myocardium, which it was normalized in the 20J and 40J groups. A higher phospholamban content was found in the 10J group. This study supports the beneficial LLLT role post-infarction. Apparently, the 10J and 20J doses show to be chosen for clinical translation.

Evaluation of Photobiomodulation on myocardial function of patients with advanced ischemic cardiomyopathy, A case series

BACKGROUND

Heart failure is a growing cardiovascular disease burden with high mortality rates, primarily attributed to myocardial ischemia. Previous studies have shown promising effects of Photobiomodulation in heart failure treatment. In this study, we aimed to investigate the effect of Photobiomodulation on myocardial function of patients with advanced ischemic heart failure.

METHOD

A non-randomized case series study involving 10 advanced heart failure patients was conducted. Patients received 15 sessions of transcutaneous and intravenous Photobiomodulation therapy using low-level red (658 nm) and infrared lasers (810 nm). All participants were evaluated by six-minute walk tests, dyspnea function classes, and echocardiography. 3 months after the sessions, the mentioned tests were reevaluated RESULT: The study included ten cardiomyopathic patients, 90 % male and the mean age was 63.20±6.01 years. The six-minute walk test change and shortness of breath function class change has 0.852 (p-value=0.006) correlation and the correlation between the Six-minute walk test change and the Systolic ejection fraction rate change, was 0.73 (p-value=0.025).

CONCLUSION

Based on the results of the study, it can be concluded that interventions in cardiomyopathic patients have shown promising improvements in certain cardiac function parameters. Specifically, the significant enhancement in the six-minute walk test post-intervention (p = 0.013) suggests a positive impact on functional capacity. Although the increase in systolic ejection fraction rate was not statistically significant (p = 0.197), the correlations identified provide valuable insights into the interplay between variables such as shortness of breath function class and the six-minute walk test. These findings underscore the complexity of managing cardiomyopathy and highlight the importance of further research to elucidate the relationships between different clinical parameters and patient outcomes in this population.

Exploring the Potential of Energy-Based Therapeutics (Photobiomodulation/Low-Level Laser Light Therapy) in Cardiovascular Disorders: A Review and Perspective

Based on the review of the literature, this article examines the potential therapeutic benefits of photobiomodulation therapy (PBMT) or low-level laser therapy (LLLT) for the treatment of cardiovascular disorders. The methodology involved searching PubMed, Google Scholar, and Central databases for relevant articles published from inception till date. The articles included in this review were preclinical and clinical studies investigating the effects of PBMT and LLLT on the heart. The article summarizes the findings of nineteen studies investigating the effects of PBMT and LLLT on various parameters related to heart failure (HF) and myocardial infarction (MI), including inflammation, oxidative stress, angiogenesis, cardiac function, and remodeling. The studies suggest that PBMT and LLLT have potential therapeutic benefits for the treatment of cardiovascular diseases and could be used in combination with traditional pharmacological therapies to enhance their effects or as a stand-alone treatment for patients who are not responsive to or cannot tolerate traditional therapies. In conclusion, this review article highlights the promising potential of PBMT for the treatment of HF and MI and the need for further research to fully understand its mechanisms of action and optimize treatment protocols.

Effect of low-level laser physiotherapy on left ventricular function among patients with chronic systolic heart failure

BACKGROUND

Low-level laser therapy (LLLT) is a promising noninvasive physiotherapeutic approach that has been demonstrated to improve cardiac performance. This study aimed to assess the impact of low-level laser therapy on cardiac functions and clinical status in patients with chronic left ventricular systolic heart failure who were not candidates for cardiac revascularization or resynchronization. A case series of 27 patients received a course of low-level laser physiotherapy, the clinical outcomes, echocardiographic parameters, and serum nitric oxide levels were evaluated before and after LLLT.

RESULTS

Of the total patients enrolled in the study, 21 (or 77.8%) were male, with a mean age of 57.7 ± 6.89 years. NYHA classification significantly improved after low-level laser therapy, 15 patients were in class III,12 were in class IV, and no one was in class II before laser therapy while after laser therapy; 25 patients shifted to class II, two patients were in class III with P < 0.001, Six-minute walk distance test was performed, and the results showed that the mean of 6MWT was less than 200 m (148.556 ± 39.092) before the study but increased to more than 300 after laser therapy (385.074 ± 61.740), left ventricular ejection fraction before laser therapy was 26 ± 7.5 while after laser therapy it became 30 ± 8.6 but diastolic function did not change after low-level laser therapy, the mean peak TR pressure was 40.0 ± 9.0 mmHg and 33.0 ± 7.0 before and after laser therapy respectively P < 0.001. A significant change was observed in NO level from 4.1 ± 1.4 IU/ml before laser therapy to 5.2 ± 1.7 IU/ml after laser therapy P < 0.001.

CONCLUSIONS

Low-level laser therapy may add benefits to improve symptoms, clinical condition, and quality of life in patients with left ventricular systolic dysfunction, further studies are necessary to evaluate the changes in cardiac functions at a longer follow-up duration.

Photobiomodulation therapy's effects on cardiac fibrosis activation after experimental myocardial infarction

INTRODUCTION

Ischemic heart disease is the leading cause of death worldwide, and interventions to reduce myocardial infarction (MI) complications are widely researched. Photobiomodulation therapy (PBMT) has altered multiple biological processes in tissues and organs, including the heart.

OBJECTIVES

This study aimed to assess the temporal effects of PBMT on cardiac fibrosis activation after MI in rats. In this proof-of-concept study, we monitored the change in expression patterns over time of genes and microRNAs (miRNAs) involved in the formation of cardiac fibrosis post-MI submitted to PBMT.

MATERIALS AND METHODS

Experimental MI was induced, and PBMT was applied shortly after coronary artery ligation (laser light of wavelength 660 nm, 15 mW of power, energy density 22.5 J/cm² , 60 seconds of application, irradiated area 0.785 cm² , fluence 1.1 J/cm² ). Ventricular septal samples were collected at 30 minutes, 3, 6, 24 hours, and 3 days post-MI to determine temporal PBMT's effects on messenger RNA (mRNA) expression associated with cardiac fibrosis activation and miRNAs expression.

RESULTS

PBMT, when applied after ischemia, reversed the changes in mRNA expression of myocardial extracellular matrix genes induced by MI. Surprisingly, PBMT modified cardiac miRNAs expression related to fibrosis replacement in the myocardium. Expression correlations between myocardial mRNAs were assessed. The correlation coefficient between miRNAs and target mRNAs was also determined. A positive correlation was detected among miR-21 and transforming growth factor beta-1 mRNA. The miR-29a expression negatively correlated to Col1a1, Col3a1, and MMP-2 mRNA expressions. In addition, we observed that miR-133 and Col1a1 mRNA were negatively correlated.

CONCLUSION

The results suggest that PBMT, through the modulation of gene transcription and miRNA expressions, can interfere in cardiac fibrosis activation after MI, mainly reversing the signaling pathway of profibrotic genes.

The effect of LED photobiomodulation on the proliferation and osteoblastic differentiation of periodontal ligament stem cells: in vitro

BACKGROUND

The aim of this study was to investigate the influence of three different light-emitting diode (LED) wavelengths on the proliferation and osteoblastic differentiation of periodontal ligament stem cells (PDLSCs) in vitro.

METHODS

PDLSCs seeded on 96- and 24-well plates, for proliferation and osteoblastic differentiation, respectively, were irradiated daily by LED light with peak emission wavelengths of 630, 680, and 830 nm at constant energy densities of 3.5 J/cm². Cultures were grown for 8 days for the proliferation assay, 10 days for the alkaline phosphatase (ALP) assay, and 28 days for Alizarin red staining. Mitochondrial activity, ALP enzyme level, and the ability to form calcium phosphate deposits were measured and compared across cultures.

RESULTS

Results obtained from statistical analysis of the experimental data indicated that the rate of proliferation (P < 0.05) in 830-nm irradiated cultures were significantly higher than the control samples at day 6 and 8; whereas, for the 630- and 680-nm groups, test results showed lower proliferation rates at day 8. For osteoblastic differentiation, significantly greater mineralization than the control samples was detected in the red-light groups (630 and 680 nm) during the late differentiation period (P < 0.001), which was supported by a higher ALP activity of the 630- and 680-nm groups in the early stage (P < 0.01).

CONCLUSION

The results of this study demonstrate that the PDLSCs responded differently to specific LED wavelengths. For enhancing cellular proliferation, 830-nm LED irradiation was more effective. On the other hand, the wavelengths of 630 and 680 nm were better for stimulating osteoblastic differentiation.

Sunlight and health: shifting the focus from vitamin D3 to photobiomodulation by red and near-infrared light

Both sun exposure and serum vitamin D levels have been associated with lower risks of all-cause mortality and chronic age-related diseases, e.g., cancer, diabetes and cardiovascular disease, in epidemiological studies. These associations have mainly been ascribed to beneficial effects of vitamin D. However, a vast body of randomized controlled trials (RCTs) and Mendelian randomization studies have failed to confirm any major health benefits from vitamin D supplementation. In this review, we present tentative evidence showing that red and near-infrared light, both being present in sunlight, could explain the associations between sunlight exposure and better health status. Body irradiation with red and near-infrared light, usually termed as photobiomodulation (PBM), has demonstrated beneficial effects in animal models of chronic diseases. Beyond this, preliminary evidence from RCTs suggest potential clinical benefit from PBM for chronic diseases. PBM is currently being investigated in many pre-registered clinical trials, results of which will eventually clarify the role of red and near-infrared light in the prevention and treatment of common age-related chronic diseases.

Photobiomodulation therapy combined with carvedilol attenuates post-infarction heart failure by suppressing excessive inflammation and oxidative stress in rats

The post-myocardial infarction heart failure (HF) still carries a huge burden since current therapy is unsuccessful to abrogate poor prognosis. Thus, new approaches are needed, and photobiomodulation therapy (PBMt) may be a way. However, it is not known whether PBMt added to a standard HF therapy provides additional improvement in cardiac remodeling in infarcted rats. This study sought to determine the combined carvedilol-drug and PBMt with low-level laser therapy value in HF. Rats with large infarcts were treated for 30 days. The functional fitness was evaluated using a motorized treadmill. Echocardiography and hemodynamic measurements were used for functional evaluations of left ventricular (LV). ELISA, Western blot and biochemical assays were used to evaluate inflammation and oxidative stress in the myocardium. Carvedilol and PBMt had a similar action in normalizing pulmonary congestion and LV end-diastolic pressure, attenuating LV dilation, and improving LV systolic function. Moreover, the application of PBMt to carvedilol-treated rats inhibited myocardial hypertrophy and improved +dP/dt of LV. PBMt alone prevented inflammation with a superior effect than carvedilol. Carvedilol and PBMt normalized 4-hydroxynonenal (a lipoperoxidation marker) levels in the myocardium. However, importantly, the addition of PBMt to carvedilol attenuated oxidized protein content and triggered a high activity of the anti-oxidant catalase enzyme. In conclusion, these data show that the use of PBMt plus carvedilol therapy results in a significant additional improvement in HF in a rat model of myocardial infarction. These beneficial effects were observed to be due, at least in part, to decreased myocardial inflammation and oxidative stress.

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.