Photobiomodulation Therapy to Autologous Bone Marrow in Humans Significantly Increases the Concentration of Circulating Stem Cells and Macrophages: A Pilot Study.

Objective: The aim of this study was to examine the effect of photobiomodulation therapy (PBMT) of the bone marrow (BM) on the concentration of stem cells and other cells in the circulating blood (CB) in humans. Background: Circulating stem cells have received increasing attention in recent years due to their potential role in regenerative medicine. Various biological processes have been shown to be affected by PBMT. Methods: The study was conducted on 15 volunteers. Ga-Al-As diode laser 808 nm wavelength was applied to both tibias of each volunteer for PBMT to the BM. The kinetics of concentration of various cells in the CB was followed by comparing blood samples relative to their baseline levels prior to application of PBMT to the BM. CD-34+ cells and macrophages were identified in CB samples using flow cytometry technology. Results: PBMT to the BM caused a significant (p < 0.01) increase in the concentration of CD-34+ cells in the CB from 7.8 ± 3.0% (mean ± SD) of total mononucleated cell to 29.5 ± 10.1% of total commencing at about 2 h post-PBMT. The levels of CD-34+ cells peaked at 2-4 days post-PBMT and then gradually returned to baseline levels. Macrophages in the CB were also significantly (p < 0.01) elevated following PBMT to the BM from 7.8 ± 6.0% (mean ± SD) of the total mononucleated cells to 52.1 ± 7.9% of total. Conclusions: Application of PBMT to the BM in humans can significantly increase the concentration of CD-34+ cells and macrophages in the CB. These cells may consequently home in on the impaired target organs and improve their function, as has been previously shown in experimental animal models. Furthermore, the results may also have clinical relevance in respect to enrichment of CB in cells that may be consequently isolated for cell therapy. Clinical Trial Registration No. is 7/14.

Adjunctive laser-stimulated stem-cells therapy to primary reperfusion in acute myocardial infarction in humans: Safety and feasibility study.

BACKGROUND: Low-level laser therapy (LLLT) has photobiostimulatory effects on stem cells and may offer cardioprotection. This cell-based therapy may compliment primary percutaneous coronary intervention (PPCI) in patients with ST-segment elevation myocardial infarction (STEMI). OBJECTIVE: In this randomized control trial, our primary objective was to determine the safety and feasibility of LLLT application to the bone marrow in patients with STEMI undergoing PPCI. METHODS: We randomly assigned patients undergoing PPCI to LLLT or non-laser therapy (NLT). In the LLLT group, 100 s of laser therapy was applied to the tibia bone prior to PPCI, as well as 24 and 72 h post-PPCI. In the control group, the power source was turned off. The primary outcome was the difference in door-to-balloon (D2B) time, and additional outcomes included differences in circulating cell counts, cardiac enzymes, and left-ventricular ejection fraction (LVEF) at pre-specified intervals post-PPCI. RESULTS: Twenty-four patients were randomized to LLLT (N = 12) or NLT (N = 12). No adverse effects of the treatment were detected. The D2B time was not significantly different between the groups (41 ± 8 vs 48 ± 1 min; P = 0.73). Creatinine Phosphokinase area under the curve, was lower after LLLT (22 ± 10) compared to NLT (49 ± 12), but this was not statistically significant (P = 0.08). Troponin-T was significantly lower after LLLT (2.7 ± 1.4 ng/mL) in comparison to NLT (5.2 ± 1.8 ng/mL. P < 0.05). At 9 months, LVEF improved in both groups without a significant difference between LLLT (55 ± 9%) and NLT (52 ± 9%; P = 0.90). CONCLUSION: LLLT is a safe and feasible adjunctive cell-based therapy to PPCI that may benefit ischemic myocardium.

Low-Level Laser Therapy to the Bone Marrow Ameliorates Neurodegenerative Disease Progression in a Mouse Model of Alzheimer's Disease: A Minireview.

OBJECTIVE: This communication reviews the ability of low-level laser therapy (LLLT) to stimulate mesenchymal stem cells (MSCs) in autologous bone marrow (BM) to enhance the capacity of MSCs to infiltrate the brain, clear ß-amyloid, and improve cognition. BACKGROUND: We recently reported that LLLT applied to the BM enhanced the proliferation of MSCs and their mobilization toward the ischemic heart region, suggesting a possible application of this approach in regenerative medicine and neurodegenerative diseases. It was also shown that circulating monocytes can infiltrate the brain and reduce brain amyloid load in an Alzheimer's disease (AD) mouse model. METHODS AND RESULTS: MSCs from wild-type mice stimulated with LLLT demonstrated an increased ability to maturate toward a monocyte lineage and to increase phagocytosis of soluble Aß in vitro. Furthermore, weekly LLLT for 2 months to the BM, starting at 4 months of age (progressive stage of the disease in these 5XFAD transgenic male mice), improved memory and spatial learning, compared to a sham-treated AD mouse model. Histology revealed a significant reduction in Aß brain burden in the laser-treated mice compared to the nonlaser-treated ones. CONCLUSIONS: The application of LLLT to the BM is suggested as a therapeutic approach in progressive stages of AD, and its potential role in mediating MSC therapy in brain amyloidogenic disease is implied.

Low-Level Laser Therapy to the Bone Marrow Reduces Scarring and Improves Heart Function Post-Acute Myocardial Infarction in the Pig.

OBJECTIVE: Cell therapy for myocardial repair is one of the most intensely investigated strategies for treating acute myocardial infarction (MI). The aim of the present study was to determine whether low-level laser therapy (LLLT) application to stem cells in the bone marrow (BM) could affect the infarcted porcine heart and reduce scarring following MI. METHODS: MI was induced in farm pigs by percutaneous balloon inflation in the left coronary artery for 90 min. Laser was applied to the tibia and iliac bones 30 min, and 2 and 7 days post-induction of MI. Pigs were euthanized 90 days post-MI. The extent of scarring was analyzed by histology and MRI, and heart function was analyzed by echocardiography. RESULTS: The number of c-kit+ cells (stem cells) in the circulating blood of the laser-treated (LT) pigs was 2.62- and 2.4-fold higher than in the non-laser-treated (NLT) pigs 24 and 48 h post-MI, respectively. The infarct size [% of scar tissue out of the left ventricle (LV) volume as measured from histology] in the LT pigs was 3.2 ± 0.82%, significantly lower, 68% (p < 0.05), than that (16.6 ± 3.7%) in the NLT pigs. The mean density of small blood vessels in the infarcted area was significantly higher [6.5-fold (p < 0.025)], in the LT pigs than in the NLT ones. Echocardiography (ECHO) analysis for heart function revealed the left ventricular ejection fraction in the LT pigs to be significantly higher than in the NLT ones. CONCLUSIONS: LLLT application to BM in the porcine model for MI caused a significant reduction in scarring, enhanced angiogenesis and functional improvement both in the acute and long term phase post-MI.

Low-level laser therapy ameliorates disease progression in a mouse model of Alzheimer's disease.

Low-level laser therapy (LLLT) has been used to treat inflammation, tissue healing, and repair processes. We recently reported that LLLT to the bone marrow (BM) led to proliferation of mesenchymal stem cells (MSCs) and their homing in the ischemic heart suggesting its role in regenerative medicine. The aim of the present study was to investigate the ability of LLLT to stimulate MSCs of autologous BM in order to affect neurological behavior and ß-amyloid burden in progressive stages of Alzheimer's disease (AD) mouse model. MSCs from wild-type mice stimulated with LLLT showed to increase their ability to maturate towards a monocyte lineage and to increase phagocytosis activity towards soluble amyloid beta (Aß). Furthermore, weekly LLLT to BM of AD mice for 2 months, starting at 4 months of age (progressive stage of AD), improved cognitive capacity and spatial learning, as compared to sham-treated AD mice. Histology revealed a significant reduction in Aß brain burden. Our results suggest the use of LLLT as a therapeutic application in progressive stages of AD and imply its role in mediating MSC therapy in brain amyloidogenic diseases.

Autologous bone-marrow stem cells stimulation reverses post-ischemic-reperfusion kidney injury in rats.

BACKGROUND/AIMS: Low-level laser therapy (LLLT) has been found to modulate biological activity. The aim of the present study was to investigate the possible beneficial effects of LLLT application to stem cells in the bone marrow (BM), on the kidneys of rats that had undergone acute ischemia-reperfusion injury (IRI). METHODS: Injury to the kidneys was induced by the excision of the left kidney and 60 min of IRI to the right kidney in each rat. Rats were then divided randomly into 2 groups: non-laser-treated and laser-treated. LLLT was applied to the BM 10 min and 24 h post-IRI and rats were sacrificed 4 days post-IRI. Blood was collected before the sacrifice and the kidney processed for histology. RESULTS: Histological evaluation of kidney sections revealed the restored structural integrity of the renal tubules, and a significant reduction of 66% of pathological score in the laser-treated rats as compared to the non-laser-treated ones. C-kit positive cell density in kidneys post-IRI and laser-treatment was (p = 0.05) 2.4-fold higher compared to that of the non-laser treated group. Creatinine, blood urea nitrogen, and cystatin-C levels were significantly 55, 48, and 25% lower respectively in the laser-treated rats as compared to non-treated ones. CONCLUSION: LLLT application to the BM causes induction of stem cells, which subsequently migrate and home in on the injured kidney. Consequently, a significant reduction in pathological features and improved kidney function post-IRI are evident. The results demonstrate a novel approach in cell-based therapy for acute ischemic injured kidneys.

Low-level laser therapy during postnatal development modulates degeneration and enhances regeneration processes in the hindlimb muscles of dystrophic mice.

OBJECTIVE: The aim of the present study was to determine whether low-level laser therapy (LLLT) at early stages postpartum could affect regeneration and degenerative processes in skeletal muscles of the dystrophic mdx mouse. BACKGROUND DATA: LLLT has been found to modulate various biological processes. It was previously shown that LLLT can markedly promote the process of skeletal muscle regeneration and angiogenesis, as well as reduce apoptosis in skeletal muscle fibers in culture. METHODS AND RESULTS: Eight newborn mdx mice were used. Ga-Al-As diode laser (810 nm) was applied at a power density of10 mW/cm(2) to the surface (area of 0.0255 cm(2)) of hindlimb muscle for 120 sec (fluence of 1.2 J/cm(2)) once a week for 4 consecutive weeks, commencing 1 week post-birth. The contralateral leg served as an untreated (sham) control. Mice were euthanized 2 days following the last laser application, and the muscles were processed for histology. Histological sections were scored for degenerative muscle foci. Statistical analysis revealed a score of 2.91±0.17 in the control, untreated group, which was significantly higher (p<0.001) than the value in the laser-treated group (1.56±0.49), indicating less degenerative foci in the laser-treated muscles. Histology also indicated regeneration (numerous myotubes) in the laser-treated mice, and no regeneration in the non-laser-treated mice. CONCLUSIONS: The results indicate that LLLT applied to mdx mice during postnatal development may have a significant beneficial effect in the induction of regenerative capacity and reduction of degenerative muscle foci in these mice, with possible direct clinical relevance.

Long-term safety of low-level laser therapy at different power densities and single or multiple applications to the bone marrow in mice.

OBJECTIVE: The purpose of this study was to determine the long-term safety effect of low-level laser therapy (LLLT) to the bone marrow (BM) in mice. BACKGROUND DATA: LLLT has been shown to have a photobiostimulatory effect on various cellular processes and on stem cells. It was recently shown that applying LLLT to BM in rats post-myocardial infarction caused a marked reduction of scar tissue formation in the heart. METHODS: Eighty-three mice were divided into five groups: control sham-treated and laser-treated at measured density of either 4, 10, 18, or 40 mW/cm(2) at the BM level. The laser was applied to the exposed flat medial part of the tibia 8 mm from the knee joint for 100 sec. Mice were monitored for 8 months and then killed, and histopathology was performed on various organs. RESULTS: No histological differences were observed in the liver, kidneys, brain or BM of the laser-treated mice as compared with the sham-treated, control mice. Moreover, no neoplasmic response in the tissues was observed in the laser-treated groups as compared with the control, sham-treated mice. There were no significant histopathological differences among the same organs under different laser treatment regimes in response to the BM-derived mesenchymal stem cell proliferation following LLLT to the BM. CONCLUSIONS: LLLT applied multiple times either at the optimal dose (which induces photobiostimulation of stem cells in the BM), or at a higher dose (such as five times the optimal dose), does not cause histopathological changes or neoplasmic response in various organs in mice, as examined over a period of 8 months.

Low-level visible light (LLVL) irradiation promotes proliferation of mesenchymal stem cells.

Low-level visible light irradiation was found to stimulate proliferation potential of various types of cells in vitro. Stem cells in general are of significance for implantation in regenerative medicine. The aim of the present study was to investigate the effect of low-level light irradiation on the proliferation of mesenchymal stem cells (MSCs). MSCs were isolated from the bone marrow, and light irradiation was applied at energy densities of 2.4, 4.8, and 7.2 J/cm(2). Illumination of the MSCs resulted in almost twofold increase in cell number as compared to controls. Elevated reactive oxygen species and nitric oxide production was also observed in MSCs cultures following illumination with broadband visible light. The present study clearly demonstrates the ability of broadband visible light illumination to promote proliferation of MSCs in vitro. These results may have an important impact on wound healing.

Enhancement of bony in-growth to metal implants by combining controlled hydroxyapatite coating and heat treatment.

The rate of bony in-growth to heat-treated and controlled hydroxyapatite metal implants made of either titanium alloy (Ti-6Al-4V) or stainless steel (SS) 316L inserted to the medullar canal of the femur in rats was investigated. It was found that while partial coverage of hydroxyapatite (HA) did not cause a significant elevation of their bonding strength when compared with nonheated implants, HA, and heat treatment caused a significant (p < 0.01) elevation of 3.1-fold in the bonding strength of the implants to the host bone. A similar phenomenon to that found for the titanium alloy implants was found to be true for the SS implants as well. It is concluded that the novel approach presented in this article, that is, to heat treat implants as well as controlled partial coating of them by HA, prior to their insertion to host bone, produce an enhancement of bone growth to metal implants greater than utilization of each method alone. Our findings may be used to further enhance bony in-growth to metal implants in several clinical settings, producing avid implants with superior integration capabilities.

Near infrared transcranial laser therapy applied at various modes to mice following traumatic brain injury significantly reduces long-term neurological deficits.

Near-infrared transcranial laser therapy (TLT) has been found to modulate various biological processes including traumatic brain injury (TBI). Following TBI in mice, in this study we assessed the possibility of various near-infrared TLT modes (pulsed versus continuous) in producing a beneficial effect on the long-term neurobehavioral outcome and brain lesions of these mice. TBI was induced by a weight-drop device, and neurobehavioral function was assessed from 1 h to 56 days post-trauma using the Neurological Severity Score (NSS). The extent of recovery is expressed as the difference in NSS (dNSS), the difference between the initial score and that at any other later time point. An 808-nm Ga-Al-As diode laser was employed transcranially 4, 6, or 8 h post-trauma to illuminate the entire cortex of the brain. Mice were divided into several groups of 6-8 mice: one control group that received a sham treatment and experimental groups that received either TLT continuous wave (CW) or pulsed wave (PW) mode transcranially. MRI was taken prior to sacrifice at 56 days post-injury. From 5-28 days post-TBI, the NSS of the laser-treated mice were significantly lower (p<0.05) than those of the non-laser-treated control mice. The percentage of surviving mice that demonstrated full recovery at 56 days post-CHI (NSS=0, as in intact mice) was the highest (63%) in the group that had received TLT in the PW mode at 100 Hz. In addition, magnetic resonance imaging (MRI) analysis demonstrated significantly smaller infarct lesion volumes in laser-treated mice compared to controls. Our data suggest that non-invasive TLT of mice post-TBI provides a significant long-term functional neurological benefit, and that the pulsed laser mode at 100 Hz is the preferred mode for such treatment.

Induction of autologous mesenchymal stem cells in the bone marrow by low-level laser therapy has profound beneficial effects on the infarcted rat heart.

BACKGROUND AND OBJECTIVES: The adult mammalian heart is known to have a very limited regenerative capacity following acute ischemia. In this study we investigated the hypothesis that photobiostimulation of autologous bone-marrow-derived mesenchymal stem cells (MSCs) by low-level laser therapy (LLLT) applied to the bone marrow (BM), may migrate to the infarcted area and thus attenuate the scarring processes following myocardial infarction (MI). MATERIALS AND METHODS: Sprague-Dawley rats underwent experimental MI. LLLT (Ga-Al-As diode laser, power density 10 mW/cm², for 100 seconds) was then applied to the BM of the exposed tibia at different time intervals post-MI (20 minutes and 4 hours). Sham-operated infarcted rats served as control. RESULTS: Infarct size and ventricular dilatation were significantly reduced (76% and 75%, respectively) in the laser-treated rats 20 minutes post-MI as compared to the control-non-treated rats at 3 weeks post-MI. There was also a significant 25-fold increase in cell density of c-kit+ cells in the infarcted area of the laser-treated rats (20 minutes post-MI) as compared to the non-laser-treated controls. CONCLUSION: The application of LLLT to autologous BM of rats post-MI offers a novel approach to induce BM-derived MSCs, which are consequently recruited from the circulation to the infarcted heart and markedly attenuate the scarring process post-MI.

Reduced axonal transport in Parkinson's disease cybrid neurites is restored by light therapy.

BACKGROUND: It has been hypothesized that reduced axonal transport contributes to the degeneration of neuronal processes in Parkinson's disease (PD). Mitochondria supply the adenosine triphosphate (ATP) needed to support axonal transport and contribute to many other cellular functions essential for the survival of neuronal cells. Furthermore, mitochondria in PD tissues are metabolically and functionally compromised. To address this hypothesis, we measured the velocity of mitochondrial movement in human transmitochondrial cybrid "cytoplasmic hybrid" neuronal cells bearing mitochondrial DNA from patients with sporadic PD and disease-free age-matched volunteer controls (CNT). The absorption of low level, near-infrared laser light by components of the mitochondrial electron transport chain (mtETC) enhances mitochondrial metabolism, stimulates oxidative phosphorylation and improves redox capacity. PD and CNT cybrid neuronal cells were exposed to near-infrared laser light to determine if the velocity of mitochondrial movement can be restored by low level light therapy (LLLT). Axonal transport of labeled mitochondria was documented by time lapse microscopy in dopaminergic PD and CNT cybrid neuronal cells before and after illumination with an 810 nm diode laser (50 mW/cm2) for 40 seconds. Oxygen utilization and assembly of mtETC complexes were also determined. RESULTS: The velocity of mitochondrial movement in PD cybrid neuronal cells (0.175 +/- 0.005 SEM) was significantly reduced (p < 0.02) compared to mitochondrial movement in disease free CNT cybrid neuronal cells (0.232 +/- 0.017 SEM). For two hours after LLLT, the average velocity of mitochondrial movement in PD cybrid neurites was significantly (p < 0.003) increased (to 0.224 +/- 0.02 SEM) and restored to levels comparable to CNT. Mitochondrial movement in CNT cybrid neurites was unaltered by LLLT (0.232 +/- 0.017 SEM). Assembly of complexes in the mtETC was reduced and oxygen utilization was altered in PD cybrid neuronal cells. PD cybrid neuronal cell lines with the most dysfunctional mtETC assembly and oxygen utilization profiles were least responsive to LLLT. CONCLUSION: The results from this study support our proposal that axonal transport is reduced in sporadic PD and that a single, brief treatment with near-infrared light can restore axonal transport to control levels. These results are the first demonstration that LLLT can increase axonal transport in model human dopaminergic neuronal cells and they suggest that LLLT could be developed as a novel treatment to improve neuronal function in patients with PD.

Implantation of low-level laser irradiated mesenchymal stem cells into the infarcted rat heart is associated with reduction in infarct size and enhanced angiogenesis.

OBJECTIVE: The aim of the present study was to evaluate the possible beneficial effects of implantation of laser-irradiated mesenchymal stem cells (MSCs) into the infarcted rat heart. BACKGROUND DATA: It was demonstrated that low-level laser therapy (LLLT) upregulates cytoprotective factors in ischemic tissues. MATERIALS AND METHODS: MSCs were isolated from rat bone marrow and grown in culture. The cells were laser irradiated with a Ga-Al-As laser (810 nm wavelength), labeled with 5-bromo-2'deoxyuridine (BrdU), and then implanted into infarcted rat hearts. Non-irradiated cells were similarly labeled and acted as controls. Hearts were excised 3 wk later and cells were stained for BrdU and c-kit immunoreactivity. RESULTS: Infarcted hearts that were implanted with laser-treated cells showed a significant reduction of 53% in infarct size compared to hearts that were implanted with non-laser-treated cells. The hearts implanted with laser-treated cells prior to implantation demonstrated a 5- and 6.3-fold significant increase in cell density that positively immunoreacted to BrdU and c-kit, respectively, as compared to hearts implanted with non-laser-treated cells. A significantly 1.4- and 2-fold higher level of angiogenesis and vascular endothelial growth factor, respectively, were observed in infarcted hearts that were implanted with laser-treated cells compared to non-laser-treated implanted cells. CONCLUSION: The findings of the present study provide the first evidence that LLLT can significantly increase survival and/or proliferation of MSCs post-implantation into the ischemic/infarcted heart, followed by a marked reduction of scarring and enhanced angiogenesis. The mechanisms associated with this phenomenon remain to be elucidated in further studies.

Primary myogenic cells see the light: improved survival of transplanted myogenic cells following low energy laser irradiation.

BACKGROUND AND OBJECTIVES: There is a substantial need for finding new avenues to promote muscle recovery when acute skeletal muscle loss extends beyond the natural capacity of the muscle to recover. Maintenance and regeneration of skeletal muscles depend mainly on resident stem cells known as satellite cells. Nevertheless, there are situations in which a significant loss of muscle tissue exhausts the satellite cell pool. For such cases, cell therapy and tissue engineering are becoming promising alternatives. Thus far, attempts to supplement damaged host muscles with donor satellite cells by means of myoblast transplantation therapy were mostly unsuccessful due to massive and rapid loss of donor cells within few hours after transplantation. This study aims at following the effects of low-energy-laser irradiation on the fate of implanted myoblasts. STUDY DESIGN: Primary myogenic cells, harvested from male rat skeletal muscles, were irradiated with low energy laser, seeded on a biodegradable scaffold and expanded in vitro. The scaffold containing cells was transplanted into partially excised muscles of host female rats. Donor cells were identified in the host muscle tissue, using Y-chromosome in situ hybridization. RESULTS: In this study, we show that laser irradiated donor primary myogenic cells not only survive, but also fuse with host myoblasts to form a host-donor syncytium. CONCLUSIONS: Our data show that the use of low energy laser irradiation (LELI), a non-surgical tool, is a promising means to enhance both the survival and functionality of transplanted primary myogenic cells.

Infrared laser therapy for ischemic stroke: a new treatment strategy: results of the NeuroThera Effectiveness and Safety Trial-1 (NEST-1).

BACKGROUND AND PURPOSE: The NeuroThera Effectiveness and Safety Trial-1 (NEST-1) study evaluated the safety and preliminary effectiveness of the NeuroThera Laser System in the ability to improve 90-day outcomes in ischemic stroke patients treated within 24 hours from stroke onset. The NeuroThera Laser System therapeutic approach involves use of infrared laser technology and has shown significant and sustained beneficial effects in animal models of ischemic stroke. METHODS: This was a prospective, intention-to-treat, multicenter, international, double-blind, trial involving 120 ischemic stroke patients treated, randomized 2:1 ratio, with 79 patients in the active treatment group and 41 in the sham (placebo) control group. Only patients with baseline stroke severity measured by National Institutes of Health Stroke Scale (NIHSS) scores of 7 to 22 were included. Patients who received tissue plasminogen activator were excluded. Outcome measures were the patients' scores on the NIHSS, modified Rankin Scale (mRS), Barthel Index, and Glasgow Outcome Scale at 90 days after treatment. The primary outcome measure, prospectively identified, was successful treatment, documented by NIHSS. This was defined as a complete recovery at day 90 (NIHSS 0 to 1), or a decrease in NIHSS score of at least 9 points (day 90 versus baseline), and was tested as a binary measure (bNIH). Secondary outcome measures included mRS, Barthel Index, and Glasgow Outcome Scale. Primary statistical analyses were performed with the Cochran-Mantel-Haenszel rank test, stratified by baseline NIHSS score or by time to treatment for the bNIH and mRS. Logistic regression analyses were conducted to confirm the results. RESULTS: Mean time to treatment was >16 hours (median time to treatment 18 hours for active and 17 hours for control). Time to treatment ranged from 2 to 24 hours. More patients (70%) in the active treatment group had successful outcomes than did controls (51%), as measured prospectively on the bNIH (P=0.035 stratified by severity and time to treatment; P=0.048 stratified only by severity). Similarly, more patients (59%) had successful outcomes than did controls (44%) as measured at 90 days as a binary mRS score of 0 to 2 (P=0.034 stratified by severity and time to treatment; P=0.043 stratified only by severity). Also, more patients in the active treatment group had successful outcomes than controls as measured by the change in mean NIHSS score from baseline to 90 days (P=0.021 stratified by time to treatment) and the full mRS ("shift in Rankin") score (P=0.020 stratified by severity and time to treatment; P=0.026 stratified only by severity). The prevalence odds ratio for bNIH was 1.40 (95% CI, 1.01 to 1.93) and for binary mRS was 1.38 (95% CI, 1.03 to 1.83), controlling for baseline severity. Similar results held for the Barthel Index and Glasgow Outcome Scale. Mortality rates and serious adverse events (SAEs) did not differ significantly (8.9% and 25.3% for active 9.8% and 36.6% for control, respectively, for mortality and SAEs). CONCLUSIONS: The NEST-1 study indicates that infrared laser therapy has shown initial safety and effectiveness for the treatment of ischemic stroke in humans when initiated within 24 hours of stroke onset. A larger confirmatory trial to demonstrate safety and effectiveness is warranted.

low-level laser therapy applied transcranially to mice following traumatic brain injury significantly reduces long-term neurological deficits.

Low-level laser therapy (LLLT) has been evaluated in this study as a potential therapy for traumatic brain injury (TBI). LLLT has been found to modulate various biological processes. Following TBI in mice, we assessed the hypothesis that LLLT might have a beneficial effect on their neurobehavioral and histological outcome. TBI was induced by a weight-drop device, and motor function was assessed 1 h post-trauma using a neurological severity score (NSS). Mice were then divided into three groups of eight mice each: one control group that received a sham LLLT procedure and was not irradiated; and two groups that received LLLT at two different doses (10 and 20 mW/cm(2) ) transcranially. An 808-nm Ga-As diode laser was employed transcranially 4 h post-trauma to illuminate the entire cortex of the brain. Motor function was assessed up to 4 weeks, and lesion volume was measured. There were no significant changes in NSS at 24 and 48 h between the laser-treated and non-treated mice. Yet, from 5 days and up to 28 days, the NSS of the laser-treated mice were significantly lower (p < 0.05) than the traumatized control mice that were not treated with the laser. The lesion volume of the laser treated mice was significantly lower (1.4%) than the non-treated group (12.1%). Our data suggest that a non-invasive transcranial application of LLLT given 4 h following TBI provides a significant long-term functional neurological benefit. Further confirmatory trials are warranted.

Low-level laser irradiation (LLLI) promotes proliferation of mesenchymal and cardiac stem cells in culture.

BACKGROUND AND OBJECTIVES: Low-level laser irradiation (LLLI) was found to promote the proliferation of various types of cells in vitro. Stem cells in general are of significance for implantation in regenerative medicine. The aim of the present study was to investigate the effect of LLLI on the proliferation of mesenchymal stem cells (MSCs) and cardiac stem cells (CSCs). STUDY DESIGN/MATERIALS AND METHODS: Isolation of MSCs and CSCs was performed. The cells were cultured and laser irradiation was applied at energy densities of 1 and 3 J/cm2. RESULTS: The number of MSCs and CSCs up to 2 and 4 weeks respectively, post-LLLI demonstrated a significant increase in the laser-treated cultures as compared to the control. CONCLUSION: The present study clearly demonstrates the ability of LLLI to promote proliferation of MSCs and CSCs in vitro. These results may have an important impact on regenerative medicine.

Effects of power densities, continuous and pulse frequencies, and number of sessions of low-level laser therapy on intact rat brain.

OBJECTIVE: The aim of the present study was to investigate the possible short- and long-term adverse neurological effects of low-level laser therapy (LLLT) given at different power densities, frequencies, and modalities on the intact rat brain. BACKGROUND DATA: LLLT has been shown to modulate biological processes depending on power density, wavelength, and frequency. To date, few well-controlled safety studies on LLLT are available. METHODS: One hundred and eighteen rats were used in the study. Diode laser (808 nm, wavelength) was used to deliver power densities of 7.5, 75, and 750 mW/cm2 transcranially to the brain cortex of mature rats, in either continuous wave (CW) or pulse (Pu) modes. Multiple doses of 7.5 mW/cm2 were also applied. Standard neurological examination of the rats was performed during the follow-up periods after laser irradiation. Histology was performed at light and electron microscopy levels. RESULTS: Both the scores from standard neurological tests and the histopathological examination indicated that there was no long-term difference between laser-treated and control groups up to 70 days post-treatment. The only rats showing an adverse neurological effect were those in the 750 mW/cm2 (about 100-fold optimal dose), CW mode group. In Pu mode, there was much less heating, and no tissue damage was noted. CONCLUSION: Long-term safety tests lasting 30 and 70 days at optimal 10x and 100x doses, as well as at multiple doses at the same power densities, indicate that the tested laser energy doses are safe under this treatment regime. Neurological deficits and histopathological damage to 750 mW/cm2 CW laser irradiation are attributed to thermal damage and not due to tissue-photon interactions.