A dual-crosslinking electroactive hydrogel based on gelatin methacrylate and dibenzaldehyde-terminated telechelic polyethylene glycol for 3D bio-printing.

Gelatin was widely used as scaffold materials in 3D bio-printing due to its excellent bioactivity and availability and especially that their arginine-glycine-aspartic acid (RGD) sequences could efficiently promote cell adhesion and proliferation. In this study, an electroactive and 3D bio-printable hydrogel was prepared through a two-step chemical cross-linking process. Specifically, residual free amino groups of methacrylated gelatin (GelMA) were cross-linked with the aldehyde groups of dibenzaldehyde-terminated telechelic polyethylene glycol (DF-PEG) via Schiff base bonds, forming a gel at 37 °C. During the subsequent 3D bio-printing process, GelMA underwent UV curing, forming a secondary cross-linked network to the mechanical strength and stability of the printed structure. The uniform dispersion of carbon nanotubes (CNTs) in the GelMA/DF-PEG composite hydrogel significantly increased its conductivity. The optimized GelMA/DF-PEG composite hydrogel, i.e., 30% GelMA and 25% DF-PEG (G30D25-CNTs), exhibited superior bio-printability. When the content of CNTs was above 4%, the conductivity of G30D25-CNTs hydrogel exceeded 10-2 S/m, which satisfied the needs of cells for micro-current stimulation. Furthermore, the pore microstructures, swelling behavior, degradation ability and cell toxicity of G30D25-CNTs electroactive hydrogels were thoroughly evaluated. Thus, the G30D25-CNTs hydrogel with 4% MWCNTs could be considered for further application in electrical stimulation of tissue regeneration such as muscle and cardiac nerve tissue repair.

A systematic review of [68Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT in the diagnostic value of malignant tumor bone metastasis.

Objective: This study aims to perform a systemic analysis of [68Ga]Ga-DOTA-FAPI-04 positron emission tomography (PET)/computerized tomography (CT) and [18F]FDG PET/CT for the diagnosis of malignant tumor bone metastasis based on existing clinical evidence. Methods: This systematic review followed the guidelines of the Preferred Reporting Project (PRISMA) for systematic reviews and meta-analysis. This is a retrospective study of articles published in PubMed. Embase was searched online from the start of May 2022. The main endpoints were the maximum standardized uptake value and the tumor-to-background ratio to determine the examination performance of [68Ga]Ga-DOTA-FAPI-04 and [18F]FDG for bone transfer stoves. Based on the entry and discharge standards, two researchers extracted documents and data and then performed the quality evaluation. Results: A total of eight studies on the metastasis of malignant tumors on bone were included, which involved 358 patients in the final analysis. Conclusion: [68Ga]Ga-DOTA-FAPI-04 showed better detection performance for bone metastasis. The sensitivity of [68Ga]Ga-DOTA-FAPI-04 for the diagnosis of the primary tumor was higher than that of [18F]FDG, whereas the specificity of [18F]FDG was higher than that of [68Ga]Ga-DOTA-FAPI-04. However, further randomized controlled trials and prospective clinical trials are warranted to compare the diagnostic performance of [68Ga]Ga-DOTA-FAPI-04 PET/CT and [18F]FDG PET/CT. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier (CRD42022313019).

Preparation, Characterization, and Preliminary Imaging Study of [188Re]Re-Ibandronate as a Novel Theranostic Radiopharmaceutical for Bone Metastasis.

Background: Bone is a common site of metastasis from a malignant tumor. Several radiopharmaceuticals are available to relieve bone pain in patients with cancer. However, every radiopharmaceutical has its own disadvantages, and there is still a need to investigate easily accessible and high bone affinity radiopharmaceuticals. Ibandronate (IBA) and 188Re were used for radiolabeling to develop and evaluate a novel type of bone-seeking radiopharmaceutical. Methods: The preparation conditions of [188Re]Re-IBA were investigated, and thin-layer chromatography was used to analyze radiochemical purity. The stability, plasma protein binding rate, lipid-water distribution coefficient, safety and biodistribution in normal mice, and bone imaging of [188Re]Re-IBA in New Zealand rabbits were studied. In addition, the nude mice model of bone metastasis was established, and biodistribution and imaging characteristics of [188Re]Re-IBA in these nude mice were studied. Results: [188Re]Re-IBA was successfully prepared with radiochemical purity >95%. The optimum preparation conditions were as follows: IBA, 0.8-1.4 mg; ascorbic acid, 0.2-0.5 mg; stannous chloride, 0.14-0.18 mg; potassium perrhenate, 0.005 mg; and [188Re]ReO4 - activity, 18.5-296 MBq, reacted for 30 min at 95°C with pH = 2. [188Re]Re-IBA demonstrated good stability, high plasma protein binding rate, good hydrophilicity, and low toxicity. The biodistribution and bone imaging in normal animals showed rapid blood clearance, high bone uptake, low uptake in the solid organs and soft tissue, and high contrast during imaging. The biodistribution and imaging of bone metastasis in nude mice showed that [188Re]Re-IBA has higher uptake in bone metastasis lesions than normal bone. Conclusions: Our study encompassed the successful preparation of [188Re]Re-IBA, a novel bone-seeking radiopharmaceutical, and confirmed it has potential in the treatment of bone metastasis and monitoring through imaging.

Organizing Pneumonia With Intense 68Ga-FAPI Uptake Mimicking Lung Cancer on 68Ga-FAPI PET/CT.

ABSTRACT: We report a case of organizing pneumonia, which revealed intense uptake on both 18F-FDG and 68Ga-FAPI (fibroblast activation protein inhibitor) PET/CT. Our findings indicate that organizing pneumonia should be taken into consideration when diagnosing a cancer-like pulmonary mass with intense 68Ga-FAPI uptake.

68Ga-DOTA-FAPI-04 PET/CT as a Promising Tool for Differentiating Ovarian Physiological Uptake: Preliminary Experience of Comparative Analysis With 18F-FDG.

Objectives: This study aimed to investigate the physiological distribution characteristics of 68Ga-DOTA-FAPI-04 in the ovary, and assess the feasibility of early diagnosis of primary ovarian disease with 68Ga-DOTA-FAPI-04 PET/CT. Methods: We retrospectively analyzed the data of patients who received 18F-FDG and 68Ga-DOTA-FAPI-04 PET/CT scanning in the Nuclear Medicine Department of our hospital within 3 days from September 2020 to January 2021. We selected the data in which ovaries showed abnormal FDG activity. Patients with abnormal ovarian FDG uptake with focus confirmed by pathological biopsy or clinical follow-up as pathological changes were excluded. The uptake of tracers (18F-FDG and 68Ga-FAPI) was semi-quantitatively analyzed. Results: This study included 14 patients (average age was 38.6). Physiological ovarian uptake was mostly unilateral, and there was no significant difference in SUVmax between the left and right sides (FDGt = 0.272, FAPIt = 0.592). The ovary SUVmax of FDG (4.89 ± 1.84) was statistically significantly higher than that of FAPI (1.53 ± 0.37). The Le/Li ratio on FDG is 3.38 ± 1.81, TBR is 5.81 ± 1.98, while the Le/Li ratio on FAPI is 3.57 ± 1.26, TBR is 0.94 ± 0.19. Conclusion: Our research shows that ovarian functional or pathological changes can be manifested as FDG avid, while 68Ga-DOTA-FAPI-04 has no physiological accumulation in the ovary and is not affected by the menstrual cycle. Therefore, 68Ga-DOTA-FAPI-04 has unique advantages in the diagnosis of ovarian diseases, and can identify them early and accurately.

Solitary Adult Rib Langerhans Cell Histiocytosis Evaluated by 18F-FDG PET/CT.

ABSTRACT: Langerhans cell histiocytosis (LCH) is a rare proliferative histiocytic disorder. It mainly occurs in the pediatric population, whereas it is rarely reported in adults. Herein, we reported a case of a patient with isolated rib LCH, which showed elevated 18F-FDG uptake. Our case showed that 18F-FDG PET/CT can be a potential tool in the evaluation of LCH.

Elevated 68Ga-FAPI Activity in the Plasmacytoma of the Ribs.

ABSTRACT: 68Ga-labeled quinoline-based fibroblast activation protein inhibitors (68Ga-FAPIs) has been used in the evaluation of a variety of malignancies. We report the case of a patient with rib plasmacytoma, which showed elevated 68Ga-FAPI activity. This case indicated fibroblast activation protein overexpression and some degree of fibrosis in the plasmacytoma lesion. Therefore, 68Ga-FAPI can be a potential tracer in the evaluation of plasmacytoma.

A Case of Solitary Laryngotracheal Lymphoma Evaluated by 18F-FDG PET/CT.

ABSTRACT: Solitary non-Hodgkin lymphoma of the trachea is extremely rare. Herein, we reported a case of solitary laryngotracheal lymphoma in a 55-year-old man. He complained of cough, tachypnea, and dyspnea. 18F-FDG PET/CT showed a hypermetabolic lesion in the subglottic larynx and upper cervical trachea. The subsequent histology and immunohistochemistry of the laryngotracheal lesion tissue confirmed the diagnosis of non-Hodgkin lymphoma (mucosa-associated lymphatic tissue lymphoma).