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Low-Level Laser Therapy Ameliorates Disease Progression in a Mouse Model of Alzheimer’s Disease

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Abstract and Figures

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 β-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 (Aβ). 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 Aβ 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.
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Low-Level Laser Therapy Ameliorates Disease Progression
in a Mouse Model of AlzheimersDisease
Dorit Farfara &Hana Tuby &Dorit Trudler &
Ella Doron-Mandel &Lidya Maltz &Robert J. Vassar &
Dan Frenkel &Uri Oron
Received: 16 April 2014 /Accepted: 11 June 2014 / Published online: 4 July 2014
#Springer Science+Business Media New York 2014
Abstract Lowlevel 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 regenera-
tive 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 β-amyloid burden in
progressive stages of Alzheimers 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 (Aβ). 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 Aβbrain 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.
Keywords Amyloid beta (Aβ)bonemarrow(BM) .
Mesenchymal stem cells (MSC) .Alzheimers Disease (AD) .
Low-level-laser therapy (LLLT)
Alzheimers disease (AD) affects more than 18 million people
worldwide and is characterized by progressive memory defi-
cits, cognitive impairment, and personality changes. The main
cause of AD is generally attributed to the increased production
and accumulation of amyloid-beta (Aß), in association with
neurofibrillary tangle (NFT) formation that leads to neuronal
death, which affects the hippocampus which is critical for
learning and memory (Selkoe 2004). The presence of stem
cells in this structure has led to an increased interest in the
phenomenon of adult neurogenesis and its role in hippocam-
pal functioning (Morgan 2007). Many known factors
impacting neurogenesis in the hippocampus are implicated
in the pathogenesis of AD (Rodriguez and Verkhratsky
2011). Since neurogenesis is modifiable, stimulation of this
process, or the potential use of stem cells, recruited endoge-
nously or implanted by transplantation, has been speculated as
a possible treatment for neurodegenerative disorders such as
AD. It was previously demonstrated that the source of a new
brain cells might be either local from the subventricular zone
(SVZ) of the forebrain (Luskin 1993; Alvarez-Buylla et al.
1998) and the subgranular zone (SGZ) of the hippocampus
(Reznikov 1991), or peripheral from the bone marrow (BM)
(Munoz et al. 2005).
The bone marrow (BM) is a complex tissue, featuring
several different types of pluripotent cells: hematopoietic stem
cells, mesenchymal stem cells (MSCs), endothelial progenitor
cells, side population cells, and multipotent adult progenitor
cells. Like other stem cells, MSCs are capable of multilineage
differentiation from a single cell and in vivo functional
D. Farfar a :D. Trudler :E. Doron-Mandel :D. Frenkel
Department of Neurobiology, George S. Wise Faculty of Life
Sciences, Tel Aviv University, Tel Aviv, Israel
H. Tuby :L. Maltz :U. Oron (*)
Department of Zoology, George S. Wise Faculty of Life Sciences,
Tel Aviv University, Tel Aviv 69978, Israel
D. Trudler :D. Frenkel
Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
R. J. Vassar
Department of Cell and Molecular Biology, Northwestern University
Feinberg School of Medicine, Chicago, IL 60611, USA
J Mol Neurosci (2015) 55:430436
DOI 10.1007/s12031-014-0354-z
reconstitution of injured tissues (Uccelli et al. 2008). One of
the properties of stem cells is their capacity to migrate to one
or more appropriate microenvironments (Devine et al. 2001).
Certain stem cells are able to exit their production site and
circulate in the blood before reseeding in their target tissues.
For MSCs, the nature of homing sites and circulation into
peripheral blood is still under debate. However, MSCs have
been found after infusion in multiple tissues, leading to the
hypothesis that they have the ability to home, and that they
adjust their differentiation pathways to diverse tissue micro-
environments (Liechty et al. 2000). It was recently shown that
intracerebral transplantation of bone-marrow-derived MSCs
into the brain of an induced AD model reduced the Aß protein
levels and accelerated the activation of microglia cells when
compared to sham-transplanted animals. Furthermore, it was
suggested that blood-derived microglia-like cells have the
ability to eliminate amyloid deposits by means of a cell-
specific phagocytic mechanism (Simard et al. 2006).
Low-level laser therapy (LLLT) has been found to
photostimulate and modulate various biological processes,
such as increasing mitochondrial respiration and ATP synthe-
sis (Bibikova and Oron 1993), facilitating wound healing, and
promoting the process of skeletal muscle regeneration and
angiogenesis (Bibikova and Oron 1993; Bibikova et al.
1994;Karu2007). It has been previously shown that laser
irradiation induces synthesis of cell-cycle regulatory proteins
in satellite cells from skeletal muscles due to the activation of
early cell-cycle regulatory genes (Shefer et al. 2001,2002). In
an experimental model of the infarcted heart in rats and dogs,
it was demonstrated that LLLT application at optimal power
parameters to the heart significantly reduces infarct size (scar
tissue formation) after myocardial infarction (Oron et al.
2001). The effect of LLLT on the brain has also been exten-
sively investigated. Transcranially applied LLLT has been
shown to have beneficial effects on AD mouse models and
rats and rabbits post stroke (Lapchak et al. 2004;Oronetal.
2006; De Taboada et al. 2011). Furthermore, LLLT was
transcranially applied in a double blinded clinical study in
patients after acute stroke (Lampl et al. 2007). The precise
mechanisms associated with the effect of LLLT on cells and
tissues are not yet clearly understood. There is evidence
suggesting that a primary mitochondrial chromophore for
photobiostimulation is cytochrome c oxidase. In addition to
leading to increased ATP formation, photobiostimulation may
also initiate secondary cell-signaling pathways (Karu 2007).
The effect of photobiostimulation on stem cells or progen-
itor cells has not been extensively studied. A remarkable
increase in stem cells counts was observed on the fourth day
of regeneration, when regenerating Dugesia tigrina (worms)
was stimulated by laser irradiation (de Souza et al. 2005).
Laser application to normal human neural progenitor cells
significantly increases ATP production in these cells (Oron
et al. 2007). LLLT was also found to significantly increase
survival and/or proliferation of MSCs post-implantation into
the ischemic heart, followed by a marked reduction of scarring
and enhanced angiogenesis (Tuby et al. 2009). Furthermore,
LLLT applied to autologous bone marrow (BM) in infarcted
heart of rats caused a 79 % reduction of the extent of scarring
in the heart developed after myocardial infarction and enhance
regeneration (Oron 2011;Tubyetal.2011,2013). This phe-
nomenon could partially be attributed to a higher extent laser
induced MSC from the BM that was mobilized via the circu-
lating blood to the infarcted area in the heart.
The effect of LLLT application to autologous BM in the
progression of AD in AD transgenic mouse model has not
been studied. In this current study, we aimed to determine
whether peripheral LLLT treatment to the BM can activate a
beneficial immune response in progressive disease stages of
AD mouse model.
Materials and Methods
Animals As an AD mouse model, we used 5XFAD transgenic
male mice (Tg6799) that co-overexpress familial AD (FAD)
mutant forms of human APP (the Swedish mutation, K670N/
M671L; the Florida mutation, I716V; and the London muta-
tion, V717I) and PS1 (M146L/L286V) trans-genes, under
transcriptional control of the neuron-specific mouse Thy-1
promoter, obtained from Robert Vassar (Northwestern
University, Chicago) (Oakley et al. 2006). Hemizygous trans-
genic mice were crossed with C57Bl/6 J breeders for at least
seven generations. Genotyping was performed by PCR anal-
ysis of tail DNA as described. The mice were housed in
individual cages in a temperature-controlled facility with a
12 h light/dark cycle. All animal care and experimental use
were in accordance with the Tel Aviv University guidelines
and approved by the Universitysanimalcarecommittee.
Object Recognition Test (ORT) At the age of 6 months, male
mice were tested using ORT (Bevins and Besheer 2006).
Object recognition is distinguished by more time spent
interacting with the novel object. Memory was operationally
defined by the discrimination index for the novel object as the
proportion of time the mice spent investigating the novel
object and the familiar one.
Fear-Conditioning Test The contextual fear-conditioning test
(FCT) was conducted as described (Saura et al. 2005). Briefly,
male mice were subjected to an unconditioned electric stimu-
lus (US footshock; 1 mA/1 s) in a pre-session training.
Twenty-four hours later, FCT was measured by scoring freez-
ing behavior (the absence of all but respiratory movement) for
180 s using a FreezeFrame automated scoring system
(Coulbourn Instruments, USA).
J Mol Neurosci (2015) 55:430436 431
Immunohistology Six-month-old male LLLT- and vehicle-
treated 5XFAD mice were sacrificed (transcardially punctured
and saline-perfused) and their brains rapidly excised and
frozen. The brains (left hemisphere) were cut in 14 μmsagittal
sections using a cryostat at 20 °C and used for histological
examination. The analysis was performed by bordering the
whole hippocampus, including the CA1, CA3, and dentate
gyrus areas. The slices were stained at Bregma 1.58 mm with
Congo-Red staining [Sigma-C6767] and Anti Aβ(6e10)
(SIG-39320500 R&D), and visualized by fluorescence mi-
croscopy for quantification of amyloid depositions.
Quantification of hippocampal Aβburden was performed
blind, using Imaging Research software from the NIH in an
unbiased stereological approach. The results are presented as
the percentage of insoluble total Aβand Congo-red positive
region from the entire hippocampus region.
LLLT Treatment A low-level laser, with a tunable power output
of maximum of 400 mW was used. LLLT to the BM of 5XFAD
and C57/B6 male mice was performed by placing the distal tip of
the fiber optic directly on the middle portion of the medial part of
the tibia after making a small incision in the skin. The beam
diameter of the laser was 0.3 cm on the BM in the tibia. The
power of irradiation of the BM was set to 1 J/cm
. Control mice
underwent the same procedure as the laser-irradiated group but
the laser was not turned on. Control- and laser-irradiated mice
were chosen randomly. Mice were treated with LLLT six times
(at 10-day intervals, for 2 months) starting at the age of 4 months
(at this time these mice already have a well-established AD
pathology). Mice were divided into three groups: Group I
(n=8), AD mice treated with LLLT every 10 days, commencing
at 4 month of age (+LLLT); Group II (n=7), sham-operated AD
mice that underwent the same procedure as the laser-irradiated
mice but without the laser irradiation (LLLT). Control- and
laser-irradiated mice were chosen randomly; and Group III
(n=6), intact WT mice of the same strain as the AD mice.
MSCs Isolation Isolation of MSCs was performed essentially
as described previously (Tuby et al. 2009). In brief, femur and
tibia bones were excised from 10 C57/B6 male mice (8 weeks
old), and the bone marrow was collected using a stainless steel
rod pushed through the marrow cavity. Cells were then seeded
in 24-well culture plates at a concentration of 1.3× 10
for 1 week (medium was changed 48 h post seeding)
as described previously (Tuby et al. 2009). The Ga-Al-As
laser (Lasotronic Inc. Switzerland) was equipped with fiber
optic was used. The cultured MSCs were exposed to the laser
for 20 s to yield 1.0 J/cm
energy density. Another set of 6-
well plates containing MSCs were sham-exposed (control) to
the laser (cells treated as above, but the laser was not turned
on). The laser-treated and the control MSCs were left in the
incubator for 3 days post-laser treatment and then incubated
until 70 % confluence.
Analysis of Aβ(142) Phagocytosis MSCs cells were incubat-
ed with 12 μM HilyteFlour TM488-Aβ(142) (ANASPEC
#69479) for 2 h. MSCs were labeled with anti-CD11b antibody
(BD Pharmigen 557397) as described (Farfara et al. 2011), and
the percentage of Aβ(142) phagocytosis was analyzed by
fluorescence-activated cell sorting (FACS).
Statistical Analysis Data are presented as mean ±Standard
error of the mean (SEM). StudentsTtest was performed
when two groups were compared. One-way analysis of vari-
ance (ANOVA) was followed by Bonferronis multiple com-
parisons tests for three samples. Pvalue of <0.05 was consid-
ered significant. *p<0.05, **p<0.01, ***p<0.0001.
Laser-Treated MSCs Increase Phagocytosis of AβProtein
with an Elevation in the Activation State.
We first aimed to evaluate the ability of laser-treated MSCs to
phagocytose Aβproteins. A significant (p=0.041) 35 % in-
crease in phagocytosis of Aß(142) was found in the cells that
were laser treated as compared to the non-laser treated
(LLLT) cells (Fig. 1a). Furthermore, a significant
(p<0.0001) 10 % increase was detected for CD11b activation
marker of monocyte-derived cells (Fig. 1b).
LLLT-Treated Mice Showed an Increased Ability in Cognitive
Tes ts
For AD mouse model, we used the 5XFAD mice that
begin to develop amyloid plaque burdens at 2 months of
age (Oakley et al. 2006). By the age of 4 months, this
mouse model possesses high amyloid load commencing in
the cortex and expanding to the hippocampus. Four-
month-old 5XFAD mice at progressive stage of disease
were treated every 10 days for 2 months with LLLT
(totaling six treatments) to their BM. A non-laser-treated
group (LLLT) and WT mice served as control. ORT was
performed in all mice at the age of 6 months. The time
spent around a new object is calculated as ratio between
the percentage of total time spent around the new object
and the old object. Application of LLLT to the BM of
5XFAD mice significantly elevated the percentage of time
spent near the new object almost to the level of the WT
mice (Fig. 2). WT 6-month-old mice demonstrated an
average of 73±4.11 % the time spent around a new
object. This value was significantly (p<0.01) reduced to
47.3±5.58 % in the group of the 6-month-old non-laser-
treated 5XFAD mice, (Fig. 2). However, the average
percentage of time spent near a new object in the laser-
432 J Mol Neurosci (2015) 55:430436
treated mice was 68.7±3 %/s (Fig. 2). There was no
statistical difference in the time spent near a new object
between the WT mice and the 5XFAD mice treated by
At six months of age, mice were subjected to a contextual
fear-conditioning test, a behavioral test widely used to evalu-
ate associative learning and memory. In this test, an automatic
(laser-assisted) system analyzed the length of time that the
mice freeze following an electric shock stimulus (1 mA/s) in a
training pre-session, 1 day earlier. In the first day of training,
mice receive an electric foot stimulus after a 3 min exploration
time. The test is conducted 24 h after the unconditional stim-
ulus, in the same apparatus, in order to evaluate memory
ability of the mice to a prior contextual stimulus. Reduced
freezing indicates memory-loss and cognitive decline.
Figure 3represents the results of the fear test of
LLLT mice compared to non-laser-treated (LLLT) as
compared to the freezing time of the WT mice.
Untreated 5XFAD mice showed a significant (p<0.001)
reduction in freezing time (11.6±4.6 s) as compared to
WT mice (71.1±4.6 s). Laser-treated 5XFAD mice
showed a significant (p<0.01) increased freezing time
of 40.4±5.28 s, compared to non-laser-treated mice.
These results indicate a significantly enhanced cognitive
ability and memory-gain in the laser-treated BM mice,
compared to non-laser-treated mice.
Reduction of β-Amyloid Burden in 5XFAD Mouse Model
Brain Following LLLT Treatment
5XFAD mice demonstrate amyloid burden starting from
2 months of age, commencing in the cortex. At 6 months of
Fig. 2 Object recognition test (ORT) of BM LLLT-treated 5XFAD mice.
Six-month-old 5XFAD mice were tested for cognition. All tested mice
(non-treated n= 7, treated n=8) were compared to WT mice, which had
shown a high percentage of time spent near the new object (n=6). Results
are expressed as mean± SEM. One-way ANOVA tests (Bonferroni) show
p<0.0011, (**p<0.01)
Fig. 1 Effect of LLLT on the
activation of BM-derived MSCs
to induce phagocytosis of
fluorescent Aß particles evaluated
by FACS. aLabeled Aβ(142)
was added for2 h to LLLT-treated
(+LLLT) MSC compared to MSC
from control mice (LLLT). b
CD11b marker for activated cells
versus MSC control mice. Results
are presented as mean± SEM of
five mice in each group. Ttest
*p<0.05, ***p<0.0001
J Mol Neurosci (2015) 55:430436 433
age, mice demonstrate a robust amyloid burden both in the
cortex and the hippocampus. To evaluate the amyloid burden
after 2 months treatment of LLLT (+LLLT), mice were
sacrificed at the age of 6 months and their brains were
snapped-frozen and immunostained with anti-Aβ(6E10)
(Fig. 4a). The percentage of Aβburden in the hippocampus
region of the non-laser-treated mice (LLLT) was 180± 15
(Fig. 4b), while in the laser-treated mice there was a signifi-
cant (p<0.05) reduction of 68 % in Aβburden relative to the
control mice (Fig. 4b).
The present study demonstrates that LLLT applied to autolo-
gous BM activate cells towards improving cognitive functions
in progressive stages of AD mouse model most probably by
increasing phagocytosis activity towards toxic Aβin the brain.
It has been suggested that LLLT may affect the immune
system (Novoselova et al. 2006; Assis et al. 2012).
Furthermore, it was shown that LLLT decrease inflammatory
cytokines while up-regulating nitric oxide in
lipopolysacharide (LPS)-treated macrophages (Gavish et al.
2008). Specific wavelengths of light trigger different inflam-
matory pathways of immune cells such as mast cells and
macrophage cells (Dube et al. 2003), which leads to increased
infiltration into the tissues. The ability of macrophages to act
as phagocytes is also modulated under the application of
LLLT (Dube et al. 2003). In addition, LLLT enhances the
proliferation, maturation, and motility of fibroblasts and in-
creases the production of basic fibroblast growth factor
(Hawkins and Abrahamse 2005). Here, we demonstrate a
significant elevation in the activation of immune cells, detect-
ed by CD11b in MSCs of the BM, following LLLT.
Furthermore, we show an increase in MSC reactivity to
phagocytose soluble neurotoxic Aβ, which tends to lead to
toxic oligomers in the brain. Indeed, it was previously sug-
gested that migration of peripherally-derived mononuclear
cells lead to clearance of amyloid load in AD mouse model
and improve cognition (Simard et al. 2006; Butovsky et al.
2007; Frenkel et al. 2008). We have recently shown that LLLT
Fig. 3 Effect of LLLT on 5XFAD mice in a FCT. Cognition in 6-month-
old mice treated with LLLT radiation (+LLLT, n=7) compared to non-
laser-treated (LLLT, n=11) and WT mice from the same background
(n=9). The results are presented as mean±SEM. One-way ANOVA tests
(Bonferroni) show p<0.0001, (**p<0.01, ***p<0.001)
Fig. 4 Effect of LLLT to BM on
amyloid burden in 5XFAD mice.
aRepresentative staining for total
insoluble Aβwith anti-Aβ
antibody (6E10) in 14 μm sagittal
hippocampal (H) sections,
focusing on the dentate gyrus
(DG) area. Bar= 200 μm. b
Quantitative analysis of Aβ
burden in the sagittal sections of
treated mice (+LLLT) compared
to non-treated mice (LLLT),
using histomorphological
software (n=6). Results are
expressed as mean± SEM. Ttest
434 J Mol Neurosci (2015) 55:430436
applied to autologous BM in infarct heart of rats after MI
caused a 79 % reduction of the extent of scarring in the heart
developed after myocardial infarction (Oron 2011;Tubyetal.
2011). This phenomenon could partially be attributed to laser-
induced MSCs from the BM that migrate to the circulating
blood and home in the infarct area in the heart. In an AD mice
model, it was shown that activation of peripheral monocyte-
derived macrophages can play a role in clearance of brain
amyloids (Miyazawa et al. 1989; Simard and Rivest 2006;
Mildner et al. 2007; Frenkel et al. 2008). Here, we show that
the laser-induced CD11b positive phagocytotic monocyte
cells, which can migrate from the BM to the circulating blood
and finally home to the brain of the 5XFAD mice, leading to a
reduction of brain amyloid load.
It was previously demonstrated that the effect of different
chemical therapeutic compounds reduce amyloid load and
improve cognition in a four months treatment time in the early
stages of the disease in 5XFAD mice (Frydman-Marom et al.
2011; Scherzer-Attali et al. 2012; Avrahami et al. 2013). In
this current study, we found that LLLT treatment leads to
significant reduction in brain amyloid load following short
period of treatment, starting at a late progressive disease stage.
Furthermore, we found that LLLT treatment improves cogni-
tive behavior in the laser-treated 5XFAD mice as compared to
non-treated mice. Our study clearly demonstrates efficacy in
significantly progressive diseased mouse model and in ad-
vanced stage of disease (4 months). These results also corre-
late with the general beneficial effect of applying LLLT
transcranially to AD mice (De Taboada et al. 2011).
However, in this current study, LLLTwas applied for a shorter
period of time and a less frequent application to autologous
BM cells as a target organ. Moreover, in the current study,
LLLT had been applied already in a progressive stage of the
disease (4 month) and not at a significant earlier stage. In
humans, this early stage is not detectable.
The results regarding the enhanced capacity of the laser-
induced CD11b positive cells in the BM to phagocytose
neurotoxic soluble Aβin vitro corroborate the in vivo findings
in this study. The amyloid burden (at 6 months) in the 5XFAD
mouse model was found to be significantly reduced in the
LLLT-treated mice as compared to control mice. The results of
the behavioral tests in this study are in concert with a reduction
of amyloid burden in the brain. They indicate a significantly
improved cognitive ability and memory in the laser-treated
mice over the non-laser-treated ones. It should be noted that
regarding the ORT, the mice that received multiple applica-
tions of LLLT to the BM between 4 and 6 months of age
demonstrated a significant improvement that reached the level
of the cognitive ability of the WT mice.
The present study also has clinical relevance. The safety of
LLLT application (at a similar power density as in the current
study) in experimental animals and in stroked human double-
blind studies has been reported (Ilic et al. 2006; Lampl et al.
2007). Moreover, we recently demonstrated that LLLT appli-
cation even at higher power densities to the BM of mice did
not cause any histological changes in various organs over a
period of almost their entire life-span (Tuby et al. 2013). Thus,
it may be assumed that LLLT to the BM in humans will be
safe. Our ability to show that LLLT application to the BM
improves cognitive brain function and reduces plaque con-
centration in the brain of 5XFAD mice, even when treatment
is commenced at a progressive stage, is of significance. It
suggests that LLLT could be applied to humans with AD,
which is usually diagnosed already in a progressive stage.
In conclusion, our results indicate a novel approach of
applying LLLT to autologous BM of AD mice, which induce
stem cells and immune cells which most probably migrate to
the brain, preventing the progression of the disease in AD
mice. LLLT thus offers a potential therapeutic strategy in
treating symptoms of Alzheimers disease and maybe other
neurodegenerative diseases.
These results suggest that laser application to monocytes or
other cell types, among the MSC population in the BM,
demonstrating phagocytotic activity, can cause significant
activation of these cells and, hence, enhance their capacity to
uptake specifically accumulated Aß proteins in the brains of
AD mice.
Acknowledgments This work is supported by grants from the
Alzheimers Association NIRG-11-205535 and ISF (to D.F.). There are
no conflicts of interest.
Alvarez-Buylla A, Garcia-Verdugo JM, Mateo AS, Merchant-Larios H
(1998) Primary neural precursors and intermitotic nuclear migration
in the ventricular zone of adult canaries. J Neurosci 18(3):1020
Assis L, Moretti AI, Abrahao TB, Cury V, Souza HP, Hamblin MR et al
(2012) Low-level laser therapy (808 nm) reduces inflammatory
response and oxidative stress in rat tibialis anterior muscle after
cryolesion. Lasers Surg Med 44(9):726735
Avrahami L, Farfara D, Shaham-Kol M, Vassar R, Frenkel D, Eldar-
Finkelman H (2013) Inhibition of glycogen synthase kinase-3 ame-
liorates beta-amyloid pathology and restores lysosomal acidification
and mammalian target of rapamycin activity in the Alzheimer dis-
ease mouse model: In vivo and in vitro studies. J Biol Chem 288(2):
Bevins RA, Besheer J (2006) Object recognition in rats and mice: a one-
trial non-matching-to-sample learning task to study recognition
memory. Nat Protoc 1(3):13061311
Bibikova A, Oron U (1993) Promotion of muscle regeneration in the toad
(Bufo viridis) gastrocnemius muscle by low-energy laser irradiation.
Anat Rec 235(3):374380
Bibikova A, Belkin V, Oron U (1994) Enhancement of angiogenesis in
regenerating gastrocnemius muscle of the toad (Bufo viridis) by
low-energy laser irradiation. Anat Embryol (Berl) 190(6):597602
Butovsky O, Kunis G, Koronyo-Hamaoui M, Schwartz M (2007)
Selective ablation of bone marrow-derived dendritic cells increases
J Mol Neurosci (2015) 55:430436 435
amyloid plaques in a mouse Alzheimers disease model. Eur J
Neurosci 26(2):413416
de Souza SC, Munin E, Alves LP, Salgado MA, Pacheco MT (2005) Low
power laser radiation at 685 nm stimulates stem-cell proliferation
rate in Dugesia tigrina during regeneration. J Photochem Photobiol
B 80(3):203207
De Taboada L, Yu J, El-Amouri S, Gattoni-Celli S, Richieri S, McCarthy
T et al (2011) Transcranial laser therapy attenuates amyloid-beta
peptide neuropathology in amyloid-beta protein precursor transgen-
ic mice. J Alzheimers Dis 23(3):521535
Devine SM, Bartholomew AM, Mahmud N, Nelson M, Patil S, Hardy W
et al (2001) Mesenchymal stem cells are capable of homing to the
bone marrow of non-human primates following systemic infusion.
Exp Hematol 29(2):244255
Dube A, Bansal H, Gupta PK (2003) Modulation of macrophage structure
and function by low level He-Ne laser irradiation. Photochem
Photobiol Sci 2(8):851855
Farfara D, Trudler D, Segev-Amzaleg N, Galron R, Stein R, Frenkel
D (2011) gamma-Secretase component presenilin is important
for microglia beta-amyloid clearance. Ann Neurol 69(1):170
Frenkel D, Puckett L, Petrovic S, Xia W, Chen G, Vega J et al (2008) A
nasal proteosome adjuvant activates microglia and prevents amyloid
deposition. Ann Neurol 63(5):591601
Frydman-Marom A, Levin A, Farfara D, Benromano T, Scherzer-Attali
R, Peled S et al (2011) Orally administrated cinnamon extract
reduces beta-amyloid oligomerization and corrects cognitive impair-
ment in Alzheimers disease animal models. PLoS One 6(1):e16564
Gavish L, Perez LS, Reissman P, Gertz SD (2008) Irradiation with
780 nm diode laser attenuates inflammatory cytokines but
upregulates nitric oxide in lipopolysaccharide-stimulated macro-
phages: Implications for the prevention of aneurysm progression.
Lasers Surg Med 40(5):371378
Hawkins D, Abrahamse H (2005) Biological effects of helium-neon laser
irradiation on normal and wounded human skin fibroblasts.
Photomed Laser Surg 23(3):251259
Ilic S, Leichliter S, Streeter J, Oron A, DeTaboada L, Oron U (2006)
Effects of power densities, continuous and pulse frequencies, and
number of sessions of low-level laser therapy on intact rat brain.
Photomed Laser Surg 24(4):458466
Karu T (2007) Ten lectures on basic science of laser photherapy. Prima
Books, Gragesberg Sweden
Lampl Y, Zivin JA, Fisher M, Lew R, Welin L, Dahlof B et al (2007)
Infrared laser therapy for ischemic stroke: a new treatment strategy:
Results of the NeuroThera Effectiveness and Safety Trial-1 (NEST-
1). Stroke 38(6):18431849
Lapchak PA, Wei J, Zivin JA (2004) Transcranial infrared laser therapy
improves clinical rating scores after embolic strokes in rabbits.
Stroke 35(8):19851988
Liechty KW, MacKenzie TC, Shaaban AF, Radu A, Moseley AM, Deans
R et al (2000) Human mesenchymal stem cells engraft and demon-
strate site-specific differentiation after in utero transplantation in
sheep. Nat Med 6(11):12821286
Luskin MB (1993) Restricted proliferation and migration of postnatally
generated neurons derived from the forebrain subventricular zone.
Neuron 11(1):173189
Mildner A, Schmidt H, Nitsche M, Merkler D, Hanisch UK, Mack M et al
(2007) Microglia in the adult brain arise from Ly-6ChiCCR2 +
monocytes only under defined host conditions. Nat Neurosci
Miyazawa T, Furuya T, Itagaki S, Tohya Y, Takahashi E, Mikami T
(1989) Establishment of a feline T-lymphoblastoid cell line highly
sensitive for replication of feline immunodeficiency virus. Arch
Virol 108(12):131135
Morgan D (2007) Amyloid, memory and neurogenesis. Exp Neurol
Munoz JR, Stoutenger BR, Robinson AP, Spees JL, Prockop DJ (2005)
Human stem/progenitor cells from bone marrow promote
neurogenesis of endogenous neural stem cells in the hippocampus
of mice. Proc Natl Acad Sci U S A 102(50):1817118176
Novoselova EG, Glushkova OV, Cherenkov DA, Chudnovsky VM,
Fesenko EE (2006) Effects of low-power laser radiation on mice
immunity. Photodermatol Photoimmunol Photomed 22(1):3338
Oakley H, Cole SL, Logan S, Maus E, Shao P, Craft J et al (2006)
Intraneuronal beta-amyloid aggregates, neurodegeneration, and neu-
ron loss in transgenic mice with five familial Alzheimersdisease
mutations: Potential factors in amyloid plaque formation. J Neurosci
Oron U (2011) Light therapy and stem cells: a therapeutic intervention of
the future. Interv Cardiol 3(6):627629
Oron U, Yaakobi T, Oron A, Hayam G, Gepstein L, Rubin O et al (2001)
Attenuation of infarct size in rats and dogs after myocardial infarc-
tion by low-energy laser irradiation. Lasers Surg Med 28(3):204
Oron A, Oron U, Chen J, Eilam A, Zhang C, Sadeh M et al (2006) Low-
level laser therapy applied transcranially to rats after induction of
stroke significantly reduces long-term neurological deficits. Stroke
Oron U, Ilic S, De Taboada L, Streeter J (2007) Ga-As (808 nm) laser
irradiation enhances ATP production in human neuronal cells in
culture. Photomed Laser Surg 25(3):180182
Reznikov KY (1991) Cell proliferation and cytogenesis in the mouse
hippocampus. Adv Anat Embryol Cell Biol 122:174
Rodriguez JJ, Verkhratsky A (2011) Neurogenesis in Alzheimersdis-
ease. J Anat 219(1):7889
Saura CA, Chen G, Malkani S, Choi SY, Takahashi RH, Zhang D et al
(2005) Conditional inactivation of presenilin 1 prevents amyloid
accumulation and temporarily rescues contextual and spatial work-
ing memory impairments in amyloid precursor protein transgenic
mice. J Neurosci 25(29):67556764
Scherzer-Attali R, Farfara D, Cooper I, Levin A, Ben-Romano T, Trudler
D et al (2012) Naphthoquinone-tyrptophan reduces neurotoxic
Abeta*56 levels and improves cognition in Alzheimers disease
animal model. Neurobiol Dis 46(3):663672
Selkoe DJ (2004) Cell biology of protein misfolding: the examples of
Alzheimers and Parkinsons diseases. Nat Cell Biol 6(11):1054
Shefer G, Oron U, Irintchev A, Wernig A, Halevy O (2001) Skeletal
muscle cell activation by low-energy laser irradiation: a role for the
MAPK/ERK pathway. J Cell Physiol 187(1):7380
Shefer G, Partridge TA, Heslop L, Gross JG, Oron U, Halevy O (2002)
Low-energy laser irradiation promotes the survival and cell cycle
entry of skeletal muscle satellite cells. J Cell Sci 115(Pt 7):14611469
Simard AR, Rivest S (2006) Bone marrow stem cells to the rescue of
Alzheimers disease. Med Sci (Paris) 22(10):822824
Simard AR, Soulet D, Gowing G, Julien JP, Rivest S (2006) Bone
marrow-derived microglia play a critical role in restricting senile
plaque formation in Alzheimers disease. Neuron 49(4):489502
Tuby H, Maltz L, Oron U (2009) Implantation of low-level laser irradi-
ated mesenchymal stem cells into the infarcted rat heart is associated
with reduction in infarct size and enhanced angiogenesis. Photomed
Laser Surg 27(2):227233
Tuby H, Maltz L, Oron U (2011) Induction of autologous mesenchymal
stem cells in the bone marrow by low-level laser therapy has
profound beneficial effects on the infarcted rat heart. Lasers Surg
Med 43(5):401409
Tuby H, Hertzberg E, Maltz L, Oron U (2013) Long-term safety of low-
level laser therapy at different power densities and single or multiple
applications to the bone marrow in mice. Photomed Laser Surg
Uccelli A, Moretta L, Pistoia V (2008) Mesenchymal stem cells in health
and disease. Nat Rev Immunol 8(9):726736
436 J Mol Neurosci (2015) 55:430436
... In one study using a mouse model of AD, NIR t-PBM was delivered to the tibia to stimulate bone marrow and mesenchymal stem cells. This was then associated with a 35% increase in the phagocytosis of Aβ and significant reduction in the Aβ brain burden [55]. In a study using TASTPM AD mice, 5-month treatment (with two treatment sessions per week) of 1072 nm NIR light delivered to the whole body resulted in an increase in heat-shock proteins (involved in maintaining healthy neurons) and a decrease in Aβ-associated proteins and plaques in the cerebral cortex, along with a reduction in tau-P [56]. ...
... Given the ever-increasing prevalence of AD [1] and the lack of effective, easily accessible treatments, the need for novel treatment strategies is dire. t-PBM is an emerging neuromodulation therapy that has a potential to treat AD [21,25,27,28,33,34,[42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58]62,63,[89][90][91], with a favorable safety profile [33,[59][60][61]. Our study will be the first to evaluate the effects of t-PBM in aMCI and mild dementia due to AD in a parallel group, sham-controlled, 8-week randomized, multi-site clinical trial. ...
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Background: Alzheimer's disease's (AD) prevalence is projected to increase as the population ages and current treatments are minimally effective. Transcranial photobiomodulation (t-PBM) with near-infrared (NIR) light penetrates into the cerebral cortex, stimulates the mitochondrial respiratory chain, and increases cerebral blood flow. Preliminary data suggests t-PBM may be efficacious in improving cognition in people with early AD and amnestic mild cognitive impairment (aMCI). Methods: In this randomized, double-blind, placebo-controlled study with aMCI and early AD participants, we will test the efficacy, safety, and impact on cognition of 24 sessions of t-PBM delivered over 8 weeks. Brain mechanisms of t-PBM in this population will be explored by testing whether the baseline tau burden (measured with 18F-MK6240), or changes in mitochondrial function over 8 weeks (assessed with 31P-MRSI), moderates the changes observed in cognitive functions after t-PBM therapy. We will also use changes in the fMRI Blood-Oxygenation-Level-Dependent (BOLD) signal after a single treatment to demonstrate t-PBM-dependent increases in prefrontal cortex blood flow. Conclusion: This study will test whether t-PBM, a low-cost, accessible, and user-friendly intervention, has the potential to improve cognition and function in an aMCI and early AD population.
... Using the 5XFAD model of AD, Farfara et al. treated mice by PBM (810 nm, 1 J/cm 2 applied to the tibia via a small incision of the skin) for 4 weeks with 10-day intervals starting at the age of 4 months. The results revealed a 68% decrease in Aβ plaques in the brain, which was associated with better performance in the object recognition and fear conditioning tests in the PBM group compared with the sham group [72]. Oron et al. discussed these results in their review as the new strategy of the PBM therapy of AD via the secondary PBM effects through photostimulation of proliferation of mesenchymal stem cells [73]. ...
... Typically, in experimental and clinical studies, PBM is performed in awake subjects [9][10][11][12][13][14][15][16][17][18][19][20][68][69][70][71][72][73][74][75][76][77][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94]. In our recent review, we suggested that there are no commercial devices for simultaneous PBM and sleep monitoring, which significantly limits the clinical investigations [36]. ...
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The global number of people with Alzheimer’s disease (AD) doubles every 5 years. It has been established that unless an effective treatment for AD is found, the incidence of AD will triple by 2060. However, pharmacological therapies for AD have failed to show effectiveness and safety. Therefore, the search for alternative methods for treating AD is an urgent problem in medicine. The lymphatic drainage and removal system of the brain (LDRSB) plays an important role in resistance to the progression of AD. The development of methods for augmentation of the LDRSB functions may contribute to progress in AD therapy. Photobiomodulation (PBM) is considered to be a non-pharmacological and safe approach for AD therapy. Here, we highlight the most recent and relevant studies of PBM for AD. We focus on emerging evidence that indicates the potential benefits of PBM during sleep for modulation of natural activation of the LDRSB at nighttime, providing effective removal of metabolites, including amyloid-β, from the brain, leading to reduced progression of AD. Our review creates a new niche in the therapy of brain diseases during sleep and sheds light on the development of smart sleep technologies for neurodegenerative diseases.
... PBM can induce local effects, but it can also induce significant systemic effects, as argued by its effect on cell metabolites (metabolome), which are crucial in determining signaling profiles, modifying phenotypic expression (such as the ability to switch macrophage phenotype from M1 to M2) and post-translational modification of proteins by tyrosination, methylation, or SUMOylation [81]. Another interesting mechanism is related to the potential interaction with the human microbiome, justifying its applicability for several systemic diseases [68,[82][83][84][85][86][87]. ...
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The development of new technologies such as sequencing has greatly enhanced our understanding of the human microbiome. The interactions between the human microbiome and the development of several diseases have been the subject of recent research. In-depth knowledge about the vaginal microbiome (VMB) has shown that dysbiosis is closely related to the development of gynecologic and obstetric disorders. To date, the progress in treating or modulating the VMB has lagged far behind research efforts. Photobiomodulation (PBM) uses low levels of light, usually red or near-infrared, to treat a diversity of conditions. Several studies have demonstrated that PBM can control the microbiome and improve the activity of the immune system. In recent years, increasing attention has been paid to the microbiome, mostly to the gut microbiome and its connections with many diseases, such as metabolic disorders, obesity, cardiovascular disorders, autoimmunity, and neurological disorders. The applicability of PBM therapeutics to treat gut dysbiosis has been studied, with promising results. The possible cellular and molecular effects of PBM on the vaginal microbiome constitute a theoretical and promising field that is starting to take its first steps. In this review, we will discuss the potential mechanisms and effects of photobiomodulation in the VMB.
... However, this therapeutic procedure may just be beneficial in the early stages of PD [286]. Also, a study detected circulating mitochondria in blood samples and showed that photobiomodulation can improve the function of these secreted intact mitochondria and may affect neural cell activities [287]. ...
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Parkinson's disease (PD) is a common age-related neurodegenerative disorder whose pathogenesis is not completely understood. Mitochondrial dysfunction and increased oxidative stress have been considered as major cause and central event responsible for the progressive degeneration of dopaminergic (DA) neurons in PD. Therefore, investigating mitochondrial disorders plays a role in understanding the pathogenesis of PD and can be an important therapeutic target for this disease. This study discusses the effect of environmental, genetic and biological factors on mitochondrial dysfunction and also focuseson the mitochondrial molecular mechanisms underlying neurodegeneration, and its possible therapeutic targets in PD, including reactive oxygen species generation, calcium overload, inflammasome activation, apoptosis, mitophagy, mitochondrial biogenesis, and mitochondrial dynamics. Other potential therapeutic strategies such as mitochondrial transfer/transplantation, targeting microRNAs, using stem cells, photobiomodulation, diet, and exercise were also discussed in this review, which may provide valuable insights into clinical aspects. A better understanding of the roles of mitochondria in the pathophysiology of PD may provide a rationale design of novel therapeutic interventions in our fight against PD.
... Regarding the physical engineering techniques, it has been so far reported that lowlevel near-infrared laser can restore functions of mitochondria and induce transcription factors [86]. In addition, the neuronal functions are recovered and the Aβ plaque can be decreased by laser treatment in model animals [87]. It is also reported that a radiofrequency electromagnetic field (1950 MHz) can lead to the improvement of AD-like symptoms in transgenic mice [88]. ...
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Amyloid fibril causes serious amyloidosis such as neurodegenerative diseases. The structure is composed of rigid β-sheet stacking conformation which makes it hard to disassemble the fibril state without denaturants. Infrared free electron laser (IR-FEL) is an intense picosecond pulsed laser that is oscillated through a linear accelerator, and the oscillation wavelengths are tunable from 3 μm to 100 μm. Many biological and organic compounds can be structurally altered by the mode-selective vibrational excitations due to the wavelength variability and the high-power oscillation energy (10–50 mJ/cm2). We have found that several different kinds of amyloid fibrils in amino acid sequences were commonly disassembled by the irradiation tuned to amide I (6.1–6.2 μm) where the abundance of β-sheet decreased while that of α-helix increased by the vibrational excitation of amide bonds. In this review, we would like to introduce the IR-FEL oscillation system briefly and describe combination studies of experiments and molecular dynamics simulations on disassembling amyloid fibrils of a short peptide (GNNQQNY) from yeast prion and 11-residue peptide (NFLNCYVSGFH) from β2-microglobulin as representative models. Finally, possible applications of IR-FEL for amyloid research can be proposed as a future outlook.
... 8,9 Low-level laser therapy (LLLT) is a safe, simple, and non-invasive treatment approach that has been considered an adjuvant therapy for various diseases including multiple sclerosis, autoimmune thyroiditis, join disorders, wound healing, Alzheimer's disease, and also RA due to its photobiomodulating effects, pain reduction and direct interference with inflammatory responses. 10,11 LLLT also has regenerative properties and could stimulate tissue repair by involving various cellular and molecular mechanisms such as adenosine triphosphate (ATP) production, nitric oxide formation, and oxidative stress modulation. 11,12 In the present review, we discussed the effect of LLLT as an adjuvant treatment on joint disorder and RA in order to improve the quality of life of RA patients. ...
Introduction: Rheumatoid arthritis (RA) is an inflammatory and autoimmune disorder that is characterized by joint inflammation, pain, physical disability, and morning stiffness. In the present study, the effect of low-level laser therapy (LLLT) on RA was reviewed. Methods: "Low-level laser therapy", "rheumatoid arthritis disease", and "photobiomodulation" keywords were searched in Google Scholar, PubMed, and Medline. Results: A literature survey led to a discussion about the immunology of the RA, laser therapy, mechanism of LLLT action, and anti-inflammatory and immunomodulatory properties of LLLT. Conclusion: It was concluded that LLLT could improve RA patients’ quality of life, reduce pain, and enhance physical movement.
This chapter explores the application of photobiomodulation (PBM) therapy for dementia, providing an overview of various types of dementia and discussing the potential benefits and limitations of PBM in both animal models and human studies. Section 1 introduces the concept of dementia, discussing its various forms, including mild cognitive impairment (1.1), Alzheimer’s disease (1.2), and vascular dementia (2.3). The chapter delves into the problem of Alzheimer's disease (1.2.1) and presents an overview of animal models used for studying Alzheimer's disease (1.2.2). Section 2 focuses on the application of PBM therapy for dementia, with subsections discussing its use in animal models (2.1) and human studies (2.2). The section provides a comprehensive overview of the current state of research, highlighting the potential benefits of PBM therapy in alleviating cognitive decline, improving memory, and promoting neuroprotection.
Non-invasive delivery of photons from an external light source to the head and thence into the brain tissue is generally referred to as transcranial photobiomodulation (PBM). In this approach, light must pass through several types of tissue, such as the scalp, skull, periosteal, meningeal, subdural space, arachnoid mater, subarachnoid space, and pia mater, successively, until reaching the cortical surface. Hair can also act as a significant attenuator of light in the visible and near-infrared (NIR) wavelengths, and its barrier role should be taken into account when other parts of head (not the forehead) are irradiated.
This review deals with an unwelcome reality about several forms of dementia, including Alzheimer’s disease— that these dementias are caused, in part or whole, by the aging of the vasculature. Since the vasculature ages in us all, dementia is our fate, sealed by the realit!ies of the circulation; it is not a disease with a cure pending. Empirically, cognitive impairment before our 7th decade is uncommon and considered early, while a diagnosis in our 11th decade is late but common in that cohort (>40%). Projections from earlier ages suggest that the prevalence of dementia in people surviving into their 12th decade exceeds 80%. We address the question why so few of many interventions known to delay dementia are recognized as therapy; and we try to resolve this few-and-many paradox, identifying opportunities for better treatment, especially pre-diagnosis. The idea of dementia as a fate is resisted, we argue, because it negates the hope of a cure. But the price of that hope is lost opportunity. An approach more in line with the evidence, and more likely to limit suffering, is to understand the damage that accumulates with age in the cerebral vasculature and therefore in the brain, and which eventually gives rise to cognitive symptoms in late life, too often leading to dementia. We argue that hope should be redirected to delaying that damage and with it the onset of cognitive loss; and, for each individual, it should be redirected to a life-long defense of their brain.
There is increasing recognition of post-COVID-19 sequelae involving chronic fatigue and brain fog for which Photobiomodulation (PBM) therapy has been utilized. This open-label, pilot, human clinical study examined the efficacy of two PBM devices - e.g., a helmet (1070 nm) for transcranial (tPBM); and a light bed (660 and 850 nm) for whole body (wbPBM) over a four-week period, with 12 treatments for two separate groups (n = 7 per group). Subjects were evaluated with a neuropsychological test battery including Montreal Cognitive Assessment (MoCA), digit symbol substitution test (DSST), trail-making tests A and B, physical reaction time (PRT); and a quantitative electroencephalography system (WAVi), Pre- and Post- the treatment series. Each device for PBM delivery was associated with significant improvements in cognitive tests (p < 0.05 and beyond). Changes in WAVi supported the findings. This study outlines the benefits of utilizing PBM therapy (transcranial or whole-body) to help treat long COVID brain fog. This article is protected by copyright. All rights reserved.
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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.
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Accumulation of β-amyloid (Aβ) deposits is a primary pathological feature of Alzheimer disease that is correlated with neurotoxicity and cognitive decline. The role of glycogen synthase kinase-3 (GSK-3) in Alzheimer disease pathogenesis has been debated. To study the role of GSK-3 in Aβ pathology, we used 5XFAD mice co-expressing mutated amyloid precursor protein and presenilin-1 that develop massive cerebral Aβ loads. Both GSK-3 isozymes (α/β) were hyperactive in this model. Nasal treatment of 5XFAD mice with a novel substrate competitive GSK-3 inhibitor, L803-mts, reduced Aβ deposits and ameliorated cognitive deficits. Analyses of 5XFAD hemi-brain samples indicated that L803-mts restored the activity of mammalian target of rapamycin (mTOR) and inhibited autophagy. Lysosomal acidification was impaired in the 5XFAD brains as indicated by reduced cathepsin D activity and decreased N-glycoyslation of the vacuolar ATPase subunit V0a1, a modification required for lysosomal acidification. Treatment with L803-mts restored lysosomal acidification in 5XFAD brains. Studies in SH-SY5Y cells confirmed that GSK-3α and GSK-3β impair lysosomal acidification and that treatment with L803-mts enhanced the acidic lysosomal pool as demonstrated in LysoTracker Red-stained cells. Furthermore, L803-mts restored impaired lysosomal acidification caused by dysfunctional presenilin-1. We provide evidence that mTOR is a target activated by GSK-3 but inhibited by impaired lysosomal acidification and elevation in amyloid precursor protein/Aβ loads. Taken together, our data indicate that GSK-3 is a player in Aβ pathology. Inhibition of GSK-3 restores lysosomal acidification that in turn enables clearance of Aβ burdens and reactivation of mTOR. These changes facilitate amelioration in cognitive function.
Low energy laser irradiation (LELI) has been shown to promote skeletal muscle cell activation and proliferation in primary cultures of satellite cells as well as in myogenic cell lines. Here, we have extended these studies to isolated myofibers. These constitute the minimum viable functional unit of the skeletal muscle, thus providing a close model of in vivo regeneration of muscle tissue. We show that LELI stimulates cell cycle entry and the accumulation of satellite cells around isolated single fibers grown under serum-free conditions and that these effects act synergistically with the addition of serum. Moreover, for the first time we show that LELI promotes the survival of fibers and their adjacent cells, as well as cultured myogenic cells, under serum-free conditions that normally lead to apoptosis. In both systems, expression of the anti-apoptotic protein Bcl-2 was markedly increased, whereas expression of the pro-apoptotic protein BAX was reduced. In culture, these changes were accompanied by a reduction in the expression of p53 and the cyclin-dependent kinase inhibitor p21, reflecting the small decrease in viable cells 24 hours after irradiation. These findings implicate regulation of these factors as part of the protective role of LELI against apoptosis. Taken together, our findings are of critical importance in attempts to improve muscle regeneration following injury.
Muscle regeneration is a complex phenomenon, involving coordinated activation of several cellular responses. During this process, oxidative stress and consequent tissue damage occur with a severity that may depend on the intensity and duration of the inflammatory response. Among the therapeutic approaches to attenuate inflammation and increase tissue repair, low-level laser therapy (LLLT) may be a safe and effective clinical procedure. The aim of this study was to evaluate the effects of LLLT on oxidative/nitrative stress and inflammatory mediators produced during a cryolesion of the tibialis anterior (TA) muscle in rats. Sixty Wistar rats were randomly divided into three groups (n = 20): control (BC), injured TA muscle without LLLT (IC), injured TA muscle submitted to LLLT (IRI). The injured region was irradiated daily for 4 consecutive days, starting immediately after the lesion using a AlGaAs laser (continuous wave, 808 nm, tip area of 0.00785 cm2, power 30 mW, application time 47 seconds, fluence 180 J/cm2; 3.8 mW/cm2; and total energy 1.4 J). The animals were sacrificed on the fourth day after injury. LLLT reduced oxidative and nitrative stress in injured muscle, decreased lipid peroxidation, nitrotyrosine formation and NO production, probably due to reduction in iNOS protein expression. Moreover, LLLT increased SOD gene expression, and decreased the inflammatory response as measured by gene expression of NF-kβ and COX-2 and by TNF-α and IL-1β concentration. These results suggest that LLLT could be an effective therapeutic approach to modulate oxidative and nitrative stress and to reduce inflammation in injured muscle. Lasers Surg. Med. 44: 726–735, 2012.
Background and Objective The aim of the present study was to investigate the possibility that low-energy laser irradiation attenuates infarct size formation after induction of chronic myocardial infarction (MI) in small and large experimental animals.Study Design/Materials and Methods Laser irradiation was applied to the infarcted area of rats and dogs at various power densities (2.5 to 20 mW/cm2) after occlusion of the coronary artery.ResultsIn infarcted laser-irradiated rats that received laser irradiation immediately and 3 days after MI at energy densities of 2.5, 6, and 20 mW/cm2, there was a 14%, 62% (significant; P < 0.05), and 2.8% reduction of infarct size (14 days after MI) relative to non–laser-irradiated rats, respectively. In dogs, a 49% (significant; P < 0.01) reduction of infarct size was achieved.Conclusion The results of the present study indicate that delivery of low-energy laser irradiation to infarcted myocardium in rats and dogs has a profound effect on the infarct size after MI. Lasers Surg. Med. 28:204–211, 2001. © 2001 Wiley-Liss, Inc.
The effect of low-energy laser (He-Ne) irradiation on the process of skeletal muscle regeneration after cold injury to the gastrocnemius muscle of the toad (Bufo viridis) was studied using quantitative histological and morphometric methods. The injured zones in the experimental toads were subjected to five direct He-Ne laser (632.8 nm wavelength) irradiations (6.0 mW for 2.3 min) every alternate day starting on the fourth day postinjury. Muscles that were injured as above, and subjected to redlight irradiation, served as a control group. Morphometric analysis was performed on histological sections of injured areas at 9, 14, and 30 days postinjury. At 9 days postinjury, mononucleated cells populated 69.3% ± 16.8% of the total area of injury. Thereafter, their volume fraction (percent of total injured zone) decreased gradually but more rapidly in the laserirradiated muscle than in the control. The volume fraction of the myotubes in the laser-irradiated muscles at 9 days of muscle regeneration was significantly higher (7.0% ± 2.2%) than in the control muscle (1.2% ± 0.4%). Young myofibers in the laser-irradiated muscles populated 15.5% ± 7.9% and 65.0% ± 9.5% of the injured area at 9 and 14 days of muscle regeneration, respectively, while in control muscles these structures were not evident at 9 days and made up only 5.3% ± 2.9% of the traumatized area at 14 days postinjury. The volume fraction of the young myofibers further increased by 30 days of muscle regeneration making up 75.7% ± 13.2% of the traumatized area, while in the laser-irradiated muscles most of the injured zone was filled with mature muscle fibers. It is concluded that He-Ne laser irradiation during the regeneration process markedly promotes muscle maturation in the injured zone following cold injury to the toad gastrocnemius muscle. © 1993 Wiley-Liss, Inc.
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). 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. 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. 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.