Repeated concussion traumatic brain injury (TBI) results in long-term brain damage and cognitive dysfunctions, leading to neurodegenerative diseases. The brain clearance system plays a crucial role in TBI recovery and neurodegenerative disease amelioration by draining waste macromolecules from the brain. Pharmacological therapeutics have failed to demonstrate benefits in human TBI. Photobiomodulation (PBM) has gained interest in neuroscience and has been shown to improve brain drainage. Here, we evaluated the efficiency of PBM in the treatment of multiple concussions in mice and the augmentation of the brain clearance system. Three consecutive closed-head concussive TBIs were induced with a 1-h interval to the left hemisphere in C57BL/6 male mice. A near-infrared irradiation (1270 nm, 10 mW/cm2) was used for PBM 4 h after the last TBI and the following 3 days twice a day. Laser speckle contrast imaging was used to assess cerebral blood flow (rCBF). In vivo 2-photon laser scanning microscopy assessed PBM effects on cerebral microcirculation, tissue oxygen supply (NADH), and meningeal lymphatics clearance. Brain compliance was evaluated by intracranial pressure waveform analysis. Neurological severity scores were obtained at 0–3 days after TBI. Two-way ANOVA for multiple comparisons was used to test intergroup differences, with the statistical significance set at p < 0.05. Multiple concussions progressively impaired rCBF, cortical microcirculation, tissue oxygen supply, and brain drainage function (p < 0.05). Compared to the sham-treated group, PBM improved rCBF, microcirculation, tissue oxygenation, and the brain drainage system (p < 0.05). Neurological function was more preserved in the PBMT group than in sham-treated mice (p < 0.05). Our study demonstrated that PBMT can be used as an adjunct therapy even in the acute period of TBI.

Background and rationale: Sirtuin 1, NAD-dependent deacetylase sirtuin-1 (Sirt1), plays a role in the regulation of mammalian metabolism that regulates transcription of factors, modulates the chromatin, and improves motor function. Here, we investigated rapid nuclear-cytoplasmic translocation of Sirt1 in ischemic stroke both neuron-specific Sirt1 knock-in (nSirt1 KI) and wild-type mice and demonstrated that Sirt1-specific inhibition by sirtinol affected the cGK1/2 signaling pathway within 6 h reperfusion an ischemia-reperfusion injury model. Methods: Both nSirt1 KI and WT mice were subjected to 1 h of ischemia, followed by 6 h of reperfusion. All mice measured rCBF by Laser Doppler. Sirtinol (10 mg/kg) was injected intraperitoneally as a single dose on 1 day. To assess the Sirt1, cGK1, and cGK2 protein expression, brain sample specimens were divided into the cerebral cortex, hippocampus, and striatum, and then protein expressions from brain lysates were studied by western blotting. Results: The conditions described above, i) The result of cerebral cortex obtained from total protein lysate was degraded the fastest by I/R injury, but no significant difference was found in Sirt1 and cGK1/2. ii) neuronal lysate from the hippocampus confirmed the degradation of Sirt1, cGK1, and cGK2. iii) On the TTC staining, within 6 h of reperfusion, the striatum does not appear to be damaged by sirtinol treatment, but it was confirmed that rapid Sirt1 translocation occurred on the intracellular mechanism. It was also demonstrated that subphase cGK1 and cGK2 were reduced in the striatum. Conclusion: These results confirm that Sirt1 inhibition by sirtinol treatment is involved in nuclear-cytoplasmic translocation in the striatum with an inhibitory mechanism of Sirt1. In addition, cGK1/2 is inhibited by sirtinol in the striatum, suggesting that cGK1/2 is also involved in inhibitors and that cGK1/2 responds as a subphase of Sirt1. These processes are expected to lead to toxic protein aggregates, inefficient transcription, and defective nuclear-cytoplasmic translocation via nuclear pore complex damage.

Photobiomodulation (PBM) using near-infrared (NIR)-II light has been shown to enhance anti-cancer immunity by reducing oxidative stress, promoting proliferation, and reducing PD-1 expression in tumor-infiltrating CD8+ T cells, ultimately suppressing tumor progression. Meanwhile, photoimmunotherapy (PIT) using NIR light has also shown promise in cancer treatment, inducing a strong anti-cancer immune response. Combining PBM with laser-based phototherapy, including PIT, could have the potential to amplify their therapeutic effects maximally, offering a promising avenue for developing safe and effective cancer therapies.

Since endothelial dysfunction is implicated in stroke pathogenesis and is featured with suppressed endothelial nitric oxide (NO) synthase (eNOS) and NO deficiency, restoring endothelial NO represents a promising approach to treating stroke injury. We have shown that near-infrared II (NIR-II) laser treatment enhances the phosphorylation of eNOS at serine 1176 (S1176) and augments NO production. Here, we further determine the beneficial effect of NIR-II laser on stroke injury. Wild-type (WT) C57BL/6J and unphosphorylatable eNOS mutant mice with S1176A mutation (S1176A) were treated by NIR-II laser (1064 nm) at an irradiance of 50 mW/cm2 (5 min daily for 4 days) prior to the middle cerebral artery occlusion (MCAO, 30 min) by a filament. The ischemic and reperfusion (30 min) values of cerebral blood flow (CBF) were confirmed by laser Doppler flowmetry. Neurological deficit and infarct volume was evaluated 48 h after reperfusion. One- and two-way ANOVAs and the Kruskal-Wallis followed by Dunn's tests were used for statistical evaluation. The NIR-II laser-pretreated WT mice demonstrated significantly increased CBF reperfusion and decreased infarct volume compared with untreated mice. The neurologic scoring showed less severe deficits in the laser-treated mice than in the non-treated mice (1.1 vs. 1.8). To determine the involvement of S1176-dependent eNOS phosphorylation in NIR-II effects, we further treated S1176A mice. MCAO followed by reperfusion resulted in decreased CBF and an increased infarct volume in S1176A mice compared to WT mice. The infarct volume was significantly larger in laser-treated S1176A compared to laser-treated WT mice. Neurological deficit in S1176A mice showed no improvement with the laser pretreatment (2.3 vs. 2.6) and was significantly more severe in the laser-treated S1176A compared to the laser-treated WT mice. In conclusion, pretreatment with a 1064 nm laser at 50 mW/cm2 improved stroke outcomes via S1176 eNOS phosphorylation. NIR-II photobiomodulation offers a non-invasive and low-risk treatment for stroke. This new modality using a physical parameter could lead to the development of innovative therapies to prevent and treat a wide array of cerebrovascular diseases.

BACKGROUND: The current management of patients with stroke with intravenous thrombolysis and endovascular thrombectomy is effective only when it is timely performed on an appropriately selected but minor fraction of patients. The development of novel adjunctive therapy is highly desired to reduce morbidity and mortality with stroke. Since endothelial dysfunction is implicated in the pathogenesis of stroke and is featured with suppressed endothelial nitric oxide synthase (eNOS) with concomitant nitric oxide deficiency, restoring endothelial nitric oxide represents a promising approach to treating stroke injury. METHODS: This is a preclinical proof-of-concept study to determine the therapeutic effect of transcranial treatment with a low-power near-infrared laser in a mouse model of ischemic stroke. The laser treatment was performed before the middle cerebral artery occlusion with a filament. To determine the involvement of eNOS phosphorylation, unphosphorylatable eNOS S1176A knock-in mice were used. Each measurement was analyzed by a 2-way ANOVA to assess the effect of the treatment on cerebral blood flow with laser Doppler flowmetry, eNOS phosphorylation by immunoblot analysis, and stroke outcomes by infarct volumes and neurological deficits. RESULTS: Pretreatment with a 1064-nm laser at an irradiance of 50 mW/cm 2 improved cerebral blood flow, eNOS phosphorylation, and stroke outcomes. CONCLUSIONS: Near-infrared II photobiomodulation could offer a noninvasive and low-risk adjunctive therapy for stroke injury. This new modality using a physical parameter merits further consideration to develop innovative therapies to prevent and treat a wide array of cardiovascular diseases.

IQ-1 (11H-indeno[1,2-b]quinoxalin-11-one oxime) is a specific c-Jun N-terminal kinase (JNK) inhibitor with anticancer and neuro- and cardioprotective properties. Because aryloxime derivatives undergo cytochrome P450-catalyzed oxidation to nitric oxide (NO) and ketones in liver microsomes, NO formation may be an additional mechanism of IQ-1 pharmacological action. In the present study, electron paramagnetic resonance (EPR) of the Fe2+ complex with diethyldithiocarbamate (DETC) as a spin trap and hemoglobin (Hb) was used to detect NO formation from IQ-1 in the liver and blood of rats, respectively, after IQ-1 intraperitoneal administration (50 mg/kg). Introducing the spin trap and IQ-1 led to signal characteristics of the complex (DETC)2-Fe2+-NO in rat liver. Similarly, the introduction of the spin trap components and IQ-1 resulted in an increase in the Hb-NO signal for both the R- and the T-conformers in blood samples. The density functional theory (DFT) calculations were in accordance with the experimental data and indicated that the NO formation of IQ-1 through the action of superoxide anion radical is thermodynamically favorable. We conclude that the administration of IQ-1 releases NO during its oxidoreductive bioconversion in vivo.

Background and rationale: Smooth muscle cell-specific cGK1 knock-out mice (SMKO) due to impaired blood vessel motility is a leading cause of reduced blood flow in ischemic stroke. This study investigated relative cerebral blood flow (rCBF), neuronal cGK1/2, and vessels cGK1/2 activity in smooth muscle cGK1 littermate control (SMLC), and SMKO mice with and without PDE5 inhibitor, dipyridamole. Methods: Middle cerebral artery occlusion (MCAO)-reperfusion was performed in SMLC and SMKO. All mice were measured for the rCBF by laser Doppler flowmetry and investigated the behaviors after ischemic stroke. To confirm the time-kinetics of cGK1/2 changes, brain samples were divided ischemia-reperfusion period in SMLC and SMKO mice with and without dipyridamole (60 mg/kg, p.o.). Results: Infarction volumes were larger in SMKO compared to that of SMLC mice and neurological deficit score was worsening in SMKO compared to that of SMLC mice. The rCBF values during MCAO and at reperfusion were significantly decreased in the SMKO group. During the ischemia and reperfusion period, neuronal cGK1 was sustained without protein degradation. Not only SMLC but also SMKO were the same. However, neuronal cGK2 was decreased time-dependent manner. In contrast, infarction volume was decreased in SMKO by dipyridamole treatment and NDS was improved in SMKO with dipyridamole. The changes of cGK1 and cGK2 were reversed in the reperfusion period in the cerebral cortex and hippocampus with dipyridamole. Conclusion: We conclude that the neuroprotective effect of dipyridamole in ischemic stroke is not only dependent on smooth muscle cell-specific cGK1 function but also related to the neuronal cGK1/2 activation via PDE5 inhibition.

Endothelial dysfunction featuring insufficient endothelial nitric oxide synthase (eNOS) and accompanying nitric oxide (NO) deficiency is implicated in the pathogenesis of cardiovascular diseases. Restoring endothelial NO represents a promising approach to treating cerebrovascular diseases, including stroke. Low-power near-infrared (NIR) light shows diverse beneficial effects, broadly defined as photobiomodulation (PBM). The literature reports that PBM increases bioavailable NO. These lines of evidence indicate that PBM could be used to treat cerebrovascular diseases. Recent investigations revealed that PBM improved stroke outcomes in animal models via augmenting NO signalling and other pathways. However, clinical trials of PBM using NIR light in the NIR-I window (630–900 nm) have yet to demonstrate the beneficial effect of PBM on ischaemic stroke. Since NIR light in the NIR-II window (1000–1700 nm) with the largest penetration depth into tissues compared to NIR I has also been reported to augment NO bioavailability and cerebral blood flow ameliorating stroke injury, PBM using NIR-II light may be suitable for therapeutic use. This new non-pharmacological modality using a physical parameter of NIR-II laser could provide a new avenue for therapeutic strategies for cerebrovascular diseases. Since impaired NO production has been associated with neurological abnormalities, this novel therapeutic approach could be broadly explored to treat various disease conditions such as traumatic brain injury, stroke, and Alzheimer’s disease. This review summarises recent findings on PBM in treating stroke and discusses its potential to treat other neurological diseases.

There is solid evidence of diverse beneficial effects of the treatment with low-power near-infrared (NIR) light in the NIR I window (630-900 nm). We have demonstrated PBM with NIR-II window (1061-1301 nm) augments the immune response of the vaccine, but other beneficial effects of NIR-II laser have not been fully explored. In this study, we have shown that NIR-II laser enhances bioavailable NO in endothelial cells. Since a hallmark of endothelial dysfunction is suppressed eNOS with concomitant NO deficiency, NIR-II laser technology could be broadly used to restore endothelial NO and treat or prevent cardiovascular diseases.

Introduction: Patients who suffer severe traumatic brain injury (sTBI) and cerebral vasospasm (CVS) frequently have posttraumatic cerebral ischemia (PCI). The research question: was to study changes in cerebral microcirculatory bed parameters in sTBI patients with CVS and with or without PCI. Material and methods: A total of 136 severe TBI patients were recruited in the study. All patients underwent perfusion computed tomography, intracranial pressure monitoring, and transcranial Doppler. The levels of cerebrovascular resistance (CVR), cerebral arterial compliance (CAC), cerebrovascular time constant (CTC), and critical closing pressure (CCP) were measured using the neuromonitoring complex. Statistical analysis was performed using parametric and nonparametric methods and factor analysis. The patients were dichotomized into PCI-positive (n = 114) and PCI-negative (n = 22) groups. Data are presented as mean values (standard deviations). Results: CVR was significantly increased, whereas CAC, CTC, and CCP were significantly decreased in sTBI patients with CVS and PCI development (p < 0.05). Factor analyses revealed that all studied microcirculatory bed parameters were significantly associated with the development of PCI (p < 0.05). Discussion and conclusion: The changes in all studied microcirculatory bed parameters in TBI patients with CVS were significantly associated with PCI development, which enables us to regard them as the biomarkers of CVS and PCI development. The causes of the described microcirculatory bed parameters changes might include complex (cytotoxic and vasogenic) brain edema development, regional microvascular spasm, and dysfunction of pericytes. A further prospective study is warranted.

Background: The influence of cerebral edema and secondary insults on the clinical outcome of traumatic brain injury (TBI) is well known. The studies of the brain water homeostasis dynamics at TBI remain rare, which determines the relevance of our work. The purpose is to study the changes in brain water homeostasis after TBI of varying severity compared to the cerebral microcirculation parameters. Materials: This non-randomized retrospective single-center study complies with the Helsinki Declaration. One hundred twenty-eight patients with posttraumatic ischemia (PCI) after moderate-to-severe TBI in the middle cerebral artery territory who presented between July 2015 and February 2022 to our hospital were included. PCI was determined using perfusion computed tomography (CT), and brain edema was determined using net water uptake (NWU) on baseline CT images. The patients were divided according to Marshall’s classification. Multivariate linear regression models were performed to analyze data. Results: NWU in PCI zones was significantly higher than in non-ischemic zones (8.1% versus 4.2%; P <0.001). In the multivariable regression analysis, the mean transit time increase was significantly and independently associated with higher NWU ( R 2 = 0,089, P <0.01). In the PCI zone, cerebral blood flow (CBF), volume (CBV), and time to peak (TTP) were not significantly associated with NWU values ( P >0.05). No significant differences existed between the NWU values in PCI foci in different Marshall groups ( P =0.308). Conclusion: The Marshall classification does not seem to be able to predict the progression of posttraumatic ischemia. The blood passage delay through the cerebral microvascular bed was significantly accompanied by brain tissue water uptake increase in the PCI focus.

Intrahospital transportation (IHT) of patients with traumatic brain injury (TBI) is common and may have adverse consequences, incurring inherent risks. The data on the frequency and severity of clinical complications linked with IHT are contradictory, and there is no agreement on whether it is safe or potentially challenging for neurocritical care unit patients. Continuous intracranial pressure (ICP) monitoring is essential in neurointensive care. The role of ICP monitoring and management of cerebral autoregulation impairments in IHT of patients with severe TBI is underinvestigated. The purpose of this nonrandomized retrospective single-center study was to assess the dynamics of ICP and an improved pressure reactivity index (iPRx) as a measure of autoregulation during IHT. Seventy-seven men and fourteen women with severe TBI admitted in 2012–2022 with a mean age of 33.2 ± 5.2 years were studied. ICP and arterial pressure were invasively monitored, and cerebral perfusion pressure and iPRx were calculated from the measured parameters. All patients were subjected to dynamic helical computed tomography angiography using a 64-slice scanner Philips Ingenuity computed tomography scan 1–2 days after TBI. Statistical analysis of all results was done using a paired t-test, and p was preset at < 0.05. The logistic regression analysis was performed for cerebral ischemia development dependent on intracranial hypertension and cerebrovascular reactivity. IHT led to an increase in ICP in all the patients, especially during vertical movement in an elevator (maximum 75.2 mm Hg). During the horizontal transportation on the floor, ICP remained increased (p < 0.05). The mean ICP during IHT was significantly higher (26.1 ± 13.5 mm Hg, p < 0.001) than that before the IHT (19.9 ± 5.3 mm Hg). The mean iPRx after and before IHT was 0.52 ± 0.04 and 0.23 ± 0.14, respectively (p < 0.001). Both horizontal and vertical transportation causes a significant increase in ICP and iPRx in patients with severe TBI, potentially leading to the outcome worsening.

Activation of c-Jun N-terminal kinases (JNKs) is involved in myocardial injury, left ventricular remodeling (LV), and heart failure (HF) after myocardial infarction (MI). The aim of this research was to evaluate the effects of a selective JNK inhibitor, 11H-indeno [1,2-b]quinoxalin-11-one oxime (IQ-1), on myocardial injury and acute myocardial ischemia/reperfusion (I/R) in adult male Wistar rats. Intraperitoneal administration of IQ-1 (25 mg/kg daily for 5 days) resulted in a significant decrease in myocardial infarct size on day 5 after MI. On day 60 after MI, a significant (2.6-fold) decrease in LV scar size, a 2.2-fold decrease in the size of the LV cavity, a 2.9-fold decrease in the area of mature connective tissue, and a 1.7-fold decrease in connective tissue in the interventricular septum were observed compared with the control group. The improved contractile function of the heart resulted in a significant (33%) increase in stroke size, a 40% increase in cardiac output, a 12% increase in LV systolic pressure, a 28% increase in the LV maximum rate of pressure rise, a 45% increase in the LV maximum rate of pressure drop, a 29% increase in the contractility index, a 14% increase in aortic pressure, a 2.7-fold decrease in LV end-diastolic pressure, and a 4.2-fold decrease in LV minimum pressure. We conclude that IQ-1 has cardioprotective activity and reduces the severity of HF after MI.

The aim of this study was to evaluate the vasoactive and neuroprotective effects of c-Jun N-terminal kinase inhibitor IQ-1 (11H-indeno[1,2-b]quinoxalin-11-one oxime) in chronic cerebral hypoperfusion caused by irreversible bilateral common carotid artery ligation [two-vessel occlusion (2VO) model]. Cerebral blood flow was measured quantitatively (hydrogen clearance method) simultaneously in the parietal cortex, hippocampus, substantia nigra, and striatum of the brain of awake rats. It was found that 2VO caused a decrease in blood flow in the brain regions with a more pronounced decrease in the cortex (by 48% of the initial level) and with a minimum drop in the substantia nigra (by 25% of the initial level). The reduced level of blood flow persisted for 14 days of measurements. The responses of the cerebral vessels to hypercapnic probes (5% CO2) were lost during the 2-week hypoperfusion period, and the neurological status of the animals did not improve. The administration of IQ-1 (50 mg/kg, intraperitoneally, every 48 h for 14 days) was accompanied by an increase in blood flow in all brain regions. A maximum increase in blood flow was observed in the striatum and a minimum in the substantia nigra. After the administration of IQ-1, the sensitivity of the cerebral vessels to the hypercapnic stimulus was restored, and the neurological state of the animals significantly improved by the end of the second week of cerebral hypoperfusion. The results show that the use of the JNK inhibitor can reduce cerebrovascular disorders and related neurological disorders in hypoperfusion brain injury.

The activation of c-Jun N-terminal kinase (JNK) plays an important role in stroke outcomes. Tryptanthrin-6-oxime (TRYP-Ox) is reported to have high affinity for JNK and anti-inflammatory activity and may be of interest as a promising neuroprotective agent. The aim of this study was to investigate the neuroprotective effects of TRYP-Ox in a rat model of transient focal cerebral ischemia (FCI), which involved intraluminal occlusion of the left middle cerebral artery (MCA) for 1 h. Animals in the experimental group were administered intraperitoneal injections of TRYP-Ox 30 min before reperfusion and 23 and 47 h after FCI. Neurological status was assessed 4, 24, and 48 h following FCI onset. Treatment with 5 and 10 mg/kg of TRYP-Ox decreased mean scores of neurological deficits by 35–49 and 46–67% at 24 and 48 h, respectively. At these doses, TRYP-Ox decreased the infarction size by 28–31% at 48 h after FCI. TRYP-Ox (10 mg/kg) reduced the content of interleukin (IL) 1β and tumor necrosis factor (TNF) in the ischemic core area of the MCA region by 33% and 38%, respectively, and attenuated cerebral edema by 11% in the left hemisphere, which was affected by infarction, and by 6% in the right, contralateral hemisphere 24 h after FCI. TRYP-Ox reduced c-Jun phosphorylation in the MCA pool at 1 h after reperfusion. TRYP-Ox was predicted to have high blood–brain barrier permeability using various calculated descriptors and binary classification trees. Indeed, reactive oxidant production was significantly lower in the brain homogenates from rats treated with TRYP-Ox versus that in control animals. Our data suggest that the neuroprotective activity of TRYP-Ox may be due to the ability of this compound to inhibit JNK and exhibit anti-inflammatory and antioxidant activity. Thus, TRYP-Ox may be considered a promising neuroprotective agent that potentially could be used for the development of new treatment strategies in cerebral ischemia.

The aim of this study was to evaluate the vasoactive and neuroprotective effects of c-Jun-N-terminal kinase inhibitor IQ-1 (11H-indeno[1,2-b]quinoxalin-11-one oxime) in chronic cerebral hypoperfusion caused by irreversible bilateral ligation of carotid arteries. Cerebral blood flow was measured quantitatively (hydrogen clearance method) simultaneously in the parietal cortex, hippocampus, substantia nigra, and striatum of the brain of awake rats. It was found that ligation of the carotid arteries caused a decrease in blood flow in the brain structures with a more pronounced decrease in the cortex (by 48% of the initial level) and with the smallest drop in the substantia nigra (by 25% of the initial level). The reduced level of blood flow persisted for 14 days of measurements. The responses of the cerebral vessels to hypercapnic probes (5% CO2) were lost during the 2-week hypoperfusion period, and the neurological status of the animals did not improve. The administration of IQ-1 (50 mg/kg, intraperitoneally, every 48 hours for 14 days) was accompanied by an increase in blood flow in all brain structures. The maximum increase in blood flow was observed in the striatum and the minimum in the substantia nigra. After the administration of IQ-1, the sensitivity of the cerebral vessels to the hypercapnic stimulus was restored and the neurological state of the animals significantly improved by the end of the second week of cerebral hypoperfusion. The results show that the use of the JNK inhibitor can reduce cerebrovascular disorders and associated neurological disorders in hypoperfusion brain injury.

BACKGROUND:The influence of cerebral edema and resultant secondary complications on the clinical outcome of traumatic brain injury (TBI) is well known. Clinical studies of brain water homeostasis dynamics in TBI are limited, which determines the relevance of our work. The purpose is to study changes in brain water homeostasis after TBI of varying severity compared to corresponding cerebral microcirculation parameters. MATERIALS:This non-randomized retrospective single-center study complies with the Helsinki Declaration for patient's studies. The study included 128 patients with posttraumatic ischemia (PCI) after moderate-to-severe TBI in the middle cerebral artery territory who were admitted to the hospital between July 2015 and February 2022. PCI was evaluated by perfusion computed tomography (CT), and brain edema was determined using net water uptake (NWU) on baseline CT images. The patients were allocated according to Marshall's classification. Multivariate linear regression models were performed to analyze data. RESULTS:NWU in PCI areas were significantly higher than in patients with its absence (8.1% vs. 4.2%, accordingly; p < 0.001). In the multivariable regression analysis, the mean transit time increase was significantly and independently associated with higher NWU (R2 = 0.089, p < 0.01). In the PCI zone, cerebral blood flow, cerebral blood volume, and time to peak were not significantly associated with NWU values (p > 0.05). No significant differences were observed between the NWU values in PCI foci in different Marshall groups (p = 0.308). CONCLUSION:Marshall's classification does not predict the progression of posttraumatic ischemia. The blood passage delays through the cerebral microvascular bed is associated with brain tissue water content increase in the PCI focus.