OBJECTIVE: Somatostatin Receptor 2 (SSTR2)-targeted radiopharmaceutical [68Ga]Ga-DOTATATE has potential advantages in the diagnosis of nasopharyngeal carcinoma (NPC). This study introduces a novel long-lasting SSTR2 analogue, LNC1010, based on DOTATATE, a truncated Evans blue-binding moiety, and a polyethylene-glycol linker. We hypothesised that peptide receptor radionuclide therapy (PRRT) is more effective with [177Lu]Lu-LNC1010 than with [177Lu]Lu-DOTATATE in treating metastatic NPC.
METHODS: We assessed binding characteristics of LNC1010 in vitro using C666-1 NPC cells and in-vivo pharmacokinetics of [68Ga]Ga/[177Lu]Lu-LNC1010 in C666-1 NPC xenografts via PET and SPECT imaging, biodistribution studies, and PRRT, and compared them with [68Ga]Ga/[177Lu] Lu-labelled DOTATATE. Furthermore, a proof-of-concept approach for imaging and therapy was conducted in a patient with metastatic NPC.
RESULTS: LNC1010 exhibited strong uptake and specific affinity for SSTR2 in C666-1 NPC cells. PET and SPECT imaging demonstrated higher uptake and longer tumour retention of [68Ga]Ga/[177Lu]Lu-LNC1010 than [68Ga]Ga/[177Lu]Lu-DOTATATE in C666-1 NPC xenografts, indicating its suitability for PRRT applications in NPCs. Biodistribution studies confirmed the higher uptake and prolonged retention of [177Lu]Lu-LNC1010 than [177Lu]Lu-DOTATATE. In preclinical PRRT studies, [177Lu]Lu-LNC1010 showed greater inhibition of tumour growth in C666-1 NPC xenografts than [177Lu]Lu-DOTATATE. In a subsequent pilot clinical study, PRRT with [177Lu]Lu-LNC1010 achieved favourable therapeutic and negligible side effects in a patient with metastatic NPC.
CONCLUSIONS: [177Lu]Lu-LNC1010 demonstrated increased tumour uptake and prolonged retention in SSTR2-positive NPCs, with superior anti-tumour efficacy to that of [177Lu]Lu-DOTATATE in preclinical studies. These findings suggest that PRRT with [177Lu]Lu-LNC1010 is a promising treatment for advanced NPC, extending the clinical scope of PRRT beyond neuroendocrine tumours.

BACKGROUND: Different types of diseases have been treated by restricted caloric intake or fasting. Although during this long time, fasting protective measures, for example, supplements, are given to the patients to protect vital organs such as the liver and kidney, little attention is given to the brain. The current research aims to investigate hypoglycemia due to prolonged fasting disrupts blood-brain barrier (BBB) in mice.
METHODS: Immunohistochemistry (IHC) and in situ hybridization (ISH) techniques were used to examine the expression of different genes. Evans blue extravasation and wet-dry technique were performed to evaluate the integrity of BBB and the formation of brain edema, respectively.
RESULTS: We confirmed that hypoglycemia affected mice fasting brain by examining the increased expression of glucose transporter protein 1 and hyperphosphorylation of tau protein. We subsequently found downregulated expression of some genes, which are involved in maintaining BBB such as vascular endothelial growth factor (VEGF) in astrocytes and claudin-5 (a vital component of BBB) and VEGF receptor (VEGFR1) in endothelial cells by ISH. We also found that prolonged fasting caused the brain endothelial cells to express lipocalin-2, an inflammatory marker of brain endothelial cells. We performed Evans blue extravasation to show more dye was retained in the brain of fasted mice than in control mice as a result of BBB disruption. Finally, wet-dry method showed that the brain of prolonged fasted mice contained significantly higher amount of water confirming the formation of brain edema. Therefore, special attention should be given to the brain during treatment with prolonged fasting for various diseases.
CONCLUSIONS: Our results demonstrated that hypoglycemia due to prolonged fasting disrupts BBB and produces brain edema in wild-type mice, highlighting the importance of brain health during treatment with prolonged fasting.

This article describes a step-by-step process of lumbar intrathecal injection of Evans blue dye and AAV9-EGFP in adult (2-month-old) and neonatal (postnatal day 10) mice. Intrathecal injection is a clinically translatable technique that has already been extensively applied in humans. In mice, intrathecal injection is considered a challenging procedure that requires a trained and experienced researcher. For both adult and neonatal mice, lumbar intrathecal injection is directed into the L5-L6 intervertebral space. Intrathecally injected material enters the cerebrospinal fluid (CSF) within the intrathecal space from where it can directly access the central nervous system (CNS) parenchyma. Simultaneously, intrathecally injected material exits the CSF with pressure gradient and enters the endoneurial fluid and ultimately the peripheral nerves. While in the CSF, the injectable material also enters the bloodstream and systemic circulation through the arachnoid villi. A successful lumbar intrathecal injection results in adequate biodistribution of the injectable material in the CNS, PNS, and peripheral organs. When correctly applied, this technique is considered as minimally invasive and non-disruptive and can be used for the lumbar delivery of any solute. © 2024 Wiley Periodicals LLC. Basic Protocol 1: C57BL/6 adult and P10 mice lumbar intrathecal injection Basic Protocol 2: Tissue collection and preparation for evaluating Evans blue dye diffusion Basic Protocol 3: Tissue collection and preparation for immunohistochemistry staining Basic Protocol 4: Tissue collection and vector genome copy number analysis.

(1) Background: Glioblastoma (GB) presents a formidable challenge in neuro-oncology due to its aggressive nature, limited treatment options, and poor prognosis. The blood-brain barrier (BBB) complicates treatment by hindering drug delivery to the tumor site, particularly to the infiltrative cells in the margin of the tumor, which are mainly responsible for tumor recurrence. Innovative strategies are therefore needed to enhance drug delivery in the margins of the tumor. This study explores whether irradiation can enhance BBB permeability by assessing hemodynamic changes and the distribution of contrast agents in the core and the margins of GB tumors. (2) Methods: Mice grafted with U-87MG cells were exposed to increasing irradiation doses. The distribution of contrast agents and hemodynamic parameters was evaluated using both non-invasive magnetic resonance imaging (MRI) techniques with gadolinium-DOTA as a contrast agent and invasive histological analysis with Evans blue, a fluorescent vascular leakage marker. Diffusion-MRI was also used to assess cytotoxic effects. (3) Results: The histological study revealed a complex dose-dependent effect of irradiation on BBB integrity, with increased vascular leakage at 5 Gy but reduced leakage at higher doses (10 and 15 Gy). However, there was no significant increase in the diffusion of Gd-DOTA outside the tumor area by MRI. (4) Conclusions: The increase in BBB permeability could be an interesting approach to enhance drug delivery in glioblastoma margins for low irradiation doses. In this model, DCE-MRI analysis was of limited value in assessing the BBB opening in glioblastoma after irradiation.

OBJECTIVE: To investigate the role of Rho/ROCK signaling pathway in mediating restraint stress-induced blood-brain barrier (BBB) injury in the amygdala of rats.
METHODS: Sixty male SD rats were randomized equally into control group (with food and water deprivation for 6 h per day), restraint stress group (with restraint for 6 h per day), stress + fasudil treatment (administered by intraperitoneal injection at 1 mg/100 g 30 min before the 6-h restraint) group, and fasudil treatment alone group. The elevated plus-maze test was used to detect behavioral changes of the rats, serum corticosterone and S100B levels were determined with ELISA, and Evans Blue leakage in the brain tissue was examined to evaluate the changes in BBB permeability. The changes in expression levels of tight junction proteins in the amygdala were detected using immunofluorescence assay and Western blotting, and Rho/ROCK pathway activation was detected by Pull-down test and Western blotting. Ultrastructural changes of the cerebral microvascular endothelial cells were observed using transmission electron microscopy.
RESULTS: Compared with those in the control group, the rats in restrain stress group and stress+fasudil group showed obvious anxiety-like behavior with significantly increased serum corticosterone level (P<0.001). Compared with those in the control group and stress+fasudil group, the rat models of restrain stress showed more obvious Evans Blue leakage and higher S100B expression (P<0.01) but lower expressions of tight junction proteins in the amygdala. Pull-down test and Western blotting confirmed that the expression levels of RhoA-GTP, ROCK2 and P-MLC 2 were significantly higher in stress group than in the control group and stress + fasudil group (P<0.05). Transmission electron microscopy revealed obvious ultrastructural changes in the cerebral microvascular endothelial cells in the rat models of restrain stress.
CONCLUSIONS: Restraint stress induces BBB injury in the amygdala of rats by activating the Rho/ROCK signaling pathway.

Overcoming the blood-brain barrier (BBB) is essential to enhance brain therapy. Here, we utilized nanobubbles with focused ultrasound for targeted and improved BBB opening in mice. A microscopy technique method assessed BBB opening at a single blood vessel resolution employing a dual-dye labeling technique using green fluorescent molecules to label blood vessels and Evans blue brain-impermeable dye for quantifying BBB extravasation. A deep learning architecture enabled blood vessels segmentation, delivering comparable accuracy to manual segmentation with a significant time reduction. Segmentation outcomes were applied to the Evans blue channel to quantify extravasation of each blood vessel. Results were compared to microbubble-mediated BBB opening, where reduced extravasation was observed in capillaries with a diameter of 2-6 μm. In comparison, nanobubbles yield an improved opening in these capillaries, and equivalent efficacy to that of microbubbles in larger vessels. These results indicate the potential of nanobubbles to serve as enhanced agents for BBB opening, amplifying bioeffects in capillaries while preserving comparable opening in larger vessels.

β--emitting 177Lu-octreotate is an approved somatostatin receptor subtype 2 (SSTR2)-directed peptide receptor radionuclide therapy for the treatment of gastroenteropancreatic neuroendocrine tumors (NETs). However,177Lu-octreotate has fast pharmacokinetics, requiring up to 4 treatment doses. Moreover, 177Lu is less than ideal for theranostics because of the low branching ratio of its γ-emissions, which limits its SPECT imaging capability. Compared with 177Lu, 67Cu has better decay properties for use as a theranostic. Here, we report the preclinical evaluation of a long-lived somatostatin analog, [67Cu]Cu-DOTA-Evans blue-TATE (EB-TATE), against SSTR2-positive NETs. Methods: The in vitro cytotoxicity of [67Cu]Cu-EB-TATE was investigated on 2-dimensional cells and 3-dimensional spheroids. In vivo pharmacokinetics and dosimetry were studied in healthy BALB/c mice, whereas ex vivo biodistribution, micro-SPECT/CT imaging, and therapy studies were done on athymic nude mice bearing QGP1.SSTR2 and BON1.SSTR2 xenografts. Therapeutic efficacy was compared with [177Lu]Lu-EB-TATE. Results: Projected human effective doses of [67Cu]Cu-EB-TATE for male (0.066 mSv/MBq) and female (0.085 mSv/MBq) patients are tolerable. In vivo micro-SPECT/CT imaging of SSTR2-positive xenografts with [67Cu]Cu-EB-TATE showed tumor-specific uptake and prolonged accumulation. Biodistribution showed tumor accumulation, with concurrent clearance from major organs over a period of 72 h. [67Cu]Cu-EB-TATE was more effective (60%) at eliminating tumors that were smaller than 50 mm3 within the first 15 d of therapy than was [177Lu]Lu-EB-TATE (20%) after treatment with 2 doses of 15 MBq administered 10 d apart. Mean survival of [67Cu]Cu-EB-TATE-treated groups was 90 d and more than 90 d, whereas that of [177Lu]Lu-EB-TATE was more than 90 d and 89 d against vehicle control groups (26 d and 53 d), for QGP1.SSTR2 and BON1.SSTR2 xenografts, respectively. Conclusion: [67Cu]Cu-EB-TATE exhibited high SSTR2-positive NET uptake and retention, with favorable dosimetry and SPECT/CT imaging capabilities. The antitumor efficacy of [67Cu]Cu-EB-TATE is comparable to that of [177Lu]Lu-EB-TATE, with [67Cu]Cu-EB-TATE being slightly more effective than [177Lu]Lu-EB-TATE for complete remission of small tumors. [67Cu]Cu-EB-TATE therefore warrants clinical development.

Glioblastoma is the deadliest form of brain tumor. The presence of the blood-brain barrier (BBB) significantly hinders chemotherapy, necessitating the development of innovative treatment options for this tumor. This report presents the in vitro and in vivo efficacy of an antibody-drug conjugate (ADC) that targets glypican-1 (GPC1) in glioblastoma. The GPC1-ADC was created by conjugating a humanized anti-GPC1 antibody (clone T2) with monomethyl auristatin E (MMAE) via maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl linkers. Immunohistochemical staining analysis of a glioblastoma tissue microarray revealed that GPC1 expression was elevated in more than half of the cases. GPC1-ADC, when bound to GPC1, was efficiently and rapidly internalized in glioblastoma cell lines. It inhibited the growth of GPC1-positive glioma cell lines by inducing cell cycle arrest in the G2/M phase and triggering apoptosis in vitro. We established a heterotopic xenograft model by subcutaneously implanting KALS-1 and administered GPC1-ADC intravenously. GPC1-ADC significantly inhibited tumor growth and increased the number of mitotic cells. We also established an orthotopic xenograft model by intracranially implanting luciferase-transfected KS-1-Luc#19. After injecting Evans blue and resecting brain tissues, dye leakage was observed in the implantation area, confirming BBB disruption. We administered GPC1-ADC intravenously and measured the luciferase activity using an in vivo imaging system. GPC1-ADC significantly inhibited tumor growth and extended survival. In conclusion, GPC1-ADC demonstrated potent intracranial activity against GPC1-positive glioblastoma in an orthotopic xenograft model. These results indicate that GPC1-ADC could represent a groundbreaking new therapy for treating glioblastoma beyond the BBB.

UNASSIGNED: : Acupuncture, practiced for millennia, lacks a clear anatomical definition for acupoints. A prevailing theory suggests that acupoints overlap with skin areas with higher mast cell density. Skin spots stained with intravenously infused Evans blue (EB), indicative of neurogenic inflammation, have recently been posited as acupoints in rats.
UNASSIGNED: : To demonstrate the concordance between EB-reactive skin spots and mast cell-enriched acupoints.
UNASSIGNED: : We employed staining and RNA-seq analysis to delineate the morphological characteristics and gene expression profiles of EB-reactive skin spots in rats.
UNASSIGNED: : EB infusion revealed a novel nodal structure on the rat skin surface, visible to the naked eye, with dimensions of approximately 1 mm in both diameter and height. Around 30 such nodes were identified on one side of the abdominal area, spaced roughly 3 mm apart, excluding the linea alba. RNA-seq analysis indicated that the gene expression patterns within these nodes markedly differed from both non-nodal skin areas and lymph nodes. Histological examination using toluidine blue revealed a significantly greater mast cell count in the nodes than in non-nodal skin regions. Additionally, the nodes stained positively with Alcian blue and Hemacolor, reagents known to mark primo vascular tissues.
UNASSIGNED: : Our findings suggest that EB-reactive nodes are indeed rich in mast cells. Further research is warranted to establish these skin nodes as surface primo nodes.

BACKGROUND: The gut-brain axis (GBA) plays a central role in cerebral ischaemia-reperfusion injury (CIRI). Rhubarb, known for its purgative properties, has demonstrated protective effects against CIRI. However, it remains unclear whether this protective effect is achieved through the regulation of the GBA.
OBJECTIVE: This study aims to investigate the mechanism by which rhubarb extract improves CIRI by modulating the GBA pathway.
METHODS: We identified the active components of rhubarb extract using LC-MS/MS. The model of middle cerebral artery occlusion (MCAO) was established to evaluate the effect of rhubarb extract. We conducted 16S rDNA sequencing and untargeted metabolomics to analyze intestinal contents. Additionally, we employed HE staining, TUNEL staining, western blot, and ELISA to assess intestinal barrier integrity. We measured the levels of inflammatory cytokines in serum via ELISA. We also examined blood-brain barrier (BBB) integrity using Evans blue (EB) penetration, transmission electron microscopy (TEM), western blot, and ELISA. Neurological function scores and TTC staining were utilized to evaluate neurological outcomes.
RESULTS: We identified twenty-six active components in rhubarb. Rhubarb extract enhanced α-diversity, reduced the abundance of Enterobacteriaceae, and partially rectified metabolic disorders in CIRI rats. It also ameliorated pathological changes, increased the expressions of ZO-1, Occludin, and Claudin 1 in the colon, and reduced levels of LPS and d-lac in serum. Furthermore, it lowered the levels of IL-1β, IL-6, IL-10, IL-17, and TNF-α in serum. Rhubarb extract mitigated BBB dysfunction, as evidenced by reduced EB penetration and improved hippocampal microstructure. It upregulated the expressions of ZO-1, Occludin, Claudin 1, while downregulating the expressions of TLR4, MyD88, and NF-κB. Similarly, rhubarb extract decreased the levels of IL-1β, IL-6, and TNF-α in the hippocampus. Ultimately, it reduced neurological function scores and cerebral infarct volume.
CONCLUSIONS: Rhubarb effectively treats CIRI, potentially by inhibiting harmful bacteria, correcting metabolic disorders, repairing intestinal barrier function, alleviating BBB dysfunction, and ultimately improving neurological outcomes.