Biodistribution and Dosimetry Evaluation for a Novel Tau Tracer [18F]-S16 in Healthy Volunteers and Its Application in Assessment of Tau Pathology in Alzheimer’s Disease

Background: The goal of this study was to report a fully automated radiosynthetic procedure of a novel tau tracer [18F]-S16 and its safety, biodistribution, and dosimetry in healthy volunteers as well as the potential utility of [18F]-S16 positron emission tomography (PET) in Alzheimer’s disease (AD).

Methods: The automated radiosynthesis of [18F]-S16 was performed on a GE Tracerlab FX2 N module. For the biodistribution and dosimetry study, healthy volunteers underwent a series of PET scans acquired at 10, 60, 120, and 240 min post-injection. The biodistribution and safety were assessed. For the AD study, both AD and healthy controls (HCs) underwent dynamic [18F]-S16 and static [18F]-FDG PET imaging. [18F]-S16 binding was assessed quantitatively using standardized uptake value ratios (SUVRs) measured at different regions of interest (ROIs). [18F]-S16 SUVRs were compared between the AD patients and HCs using the Mann–Whitney U-test. In AD patients with all cortical ROIs, Spearman rank-correlation analysis was used to calculate the voxel-wise correlations between [18F]-S16 and [18F]-FDG.

Results: The automated radiosynthesis of [18F]-S16 was finished within 45 min, with a radiochemical yield of 30 ± 5% (n = 8, non-decay-corrected). The radiochemical purity was greater than 98%, and the specific activity was calculated to be 1,047 ± 450 GBq/μmol (n = 5), and [18F]-S16 was stable in vitro. In the healthy volunteer study, no adverse effect was observed within 24 h post-injection, and no defluorination was observed in vivo. The radiotracer could pass through the blood–brain barrier easily and was rapidly cleared from the circulation and excreted through the hepatic system. The whole-body mean effective dose was 15.3 ± 0.3 μSv/MBq. In AD patients, [18F]-S16 accumulation was identified as involving the parietal, temporal, precuneus, posterior cingulate, and frontal lobes. No specific [18F]-S16 cerebral uptake was identified in HCs. The SUVR of AD patients was significantly higher than that of HCs. No specific binding uptake was found in the choroid plexus, venous sinus, and white matter. A significant correlation was found between [18F]-S16 binding and hypometabolism across neocortical regions.

Conclusion: [18F]-S16 could be synthesized automatically, and it showed favorable biodistribution and safety in humans. [18F]-S16 PET indicated a high image quality for imaging tau deposition in AD and distinguishing AD from HCs.

[Effect of metformin combined with intermittent fasting on endoplasmic reticulum stress after cerebral ischemia-reperfusion in mice]

Objective: To explore the effect of metformin combined with intermittent fasting on endoplasmic reticulum stress after cerebral ischemia-reperfusion injury in mice. Methods: One hundred 10-Week-old healthy KM mice of SPF grade, weighing 25-28 g, were divided into 5 groups by the random number table method: sham group, focal cerebral ischemia group (I/R group), intermittent fasting group (IF group), metformin group (Met group), metformin+intermittent fasting group (Met+IF group). In IF group, food was provided ad libitum from 8∶00 to 16∶00 daily, but the mice were fasted for the rest of the time. In Met group, the mice underwent intraperitoneal injection of metformin (10 mg/kg). In Met+IF group, the mice received the same eating method as the IF group and the same method of metformin injection as Met Group. In Sham group, I/R group and IF group, the mice were intraperitoneally injected with equal volume of normal saline. Mice in all groups were not restricted to drinking water. Random plasma glucose and body weight changes in mice during preconditioning were monitored, and a focal cerebral ischemia-reperfusion model was established 14 days later. The cerebral infarction volume was measured after 1 hour of ischemia and 24 hours of reperfusion. The brain tissues of mice were subjected to Western blot to detect the contents of endoplasmic reticulum stress-related proteins, including glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), and apoptosis proteins (Caspase-3 and Cleaved-caspase 3). Results: After different interventions, there was no significant difference in random plasma glucose changes among the four groups (all P<0.05). The blood glucose level of the mice in the Met+IF group was lower than the sham group, I/R group, IF group and Met group (all P<0.05). GRP78/β-actin in sham group, I/R group, IF group, Met group, IF+Met group were 0.48±0.05, 1.35±0.10, 0.94±0.05, 0.70±0.14, 0.41±0.37, respectively; CHOP/β-actin were 0.27±0.04, 1.03±0.03, 0.72±0.04, 0.63±0.04, 0.44±0.01, respectively; Caspase-3/β-actin were 0.51±0.04, 1.04±0.04, 0.83±0.03, 0.76±0.03, 0.63±0.05, respectively; Cleaved-Caspase-3/β-actin were 0.17±0.06, 1.01±0.20, 0.75±0.06, 0.51±0.12, 0.29±0.08, respectively, with statistically significant differences (all P<0.001). The counts of GRP78-positive cells in the hippocampus immunohistochemistry in the sham group, I/R group, IF group, Met group, and IF+Met group were 53±5, 192±11, 162±12, 140±10, 114±13, respectively, while the counts of CHOP-positive cells were 35±4, 177±12, 120±12, 100±7, 69±10, respectively, with statistically significant differences (all P<0.001). The relative volume of cerebral infarction in I/R group, IF group, Met group and IF+Met group were 0, 0.333±0.046, 0.258±0.023, 0.116±0.039, 0.111±0.039, respectively, and there were statistically significant differences (all P<0.001). Conclusion: Both Metformin and intermittent fasting can alleviate endoplasmic reticulum stress after cerebral ischemia and reperfusion in mice, and the combination of the two has a better effect.

[Clinical analysis of 10 cases with extramedullary plasmacytoma of the head and neck]

Objective: To explore the clinical characteristics, treatment methods and outcomes of extramedullary plasmacytoma of the head and neck. Methods: A retrospective analysis was conducted on 10 cases with extramedullary plasmacytoma of the head and neck who were admitted to Henan Tumor Hospital from January 2005 to January 2020. Among the 10 patients, 6 were male and 4 were female. The average age at diagnosis was 56.3 years old (34-74 years old). Among them, 3 cases were located in the nasal cavity, 2 cases in the nasopharynx, 1 case in the sinuses, 2 cases in the larynx, 1 case in the oropharynx, and 1 case in the cervical lymph nodes. Treatments were administered according to tumor size and resection extent. Complete surgical excision (negative margins) was preferred, followed by adjuvant radiotherapy or radiotherapy alone. The clinical characteristics, diagnosis, treatment and prognosis of EMP were analyzed. Results: The patients' symptoms were not specific, frequently with local obstruction symptom and localized masses. All patients were confirmed pathologically as suffering from monoclonal plasmacytoma, with negative bone marrow biopsy and negative skeletal survey. Five patients received surgery, 3 received radiotherapy, and 2 received surgery with additional radiation. The follow-up time was 16-125 months, with a median of 92 months. Two patients developed into multiple myeloma. One patient who received radiotherapy after surgery relapsed after 7 years of follow-up and again received surgical treatment, with no evidence of second recurrence. The remaining patients had no recurrence or progression. Conclusion: Extramedullary plasmacytoma of the head and neck has a good prognosis. Surgical treatment can be considered for completely resectable lesions.

68Ga-DOTA-DiPSMA PET/CT Imaging: Biodistribution, Dosimetry, and Preliminary Application in Prostate Cancer

Purpose: This prospective trial aimed to evaluate the safety, dosimetry, and biodistribution of a novel theranostic probe ⁶⁸Ga-DOTA-DiPSMA. Also, we have performed the first preliminary application with ⁶⁸Ga-DOTA-DiPSMA in prostate cancer (PCa) patients.

Methods: Five healthy volunteers and ten PCa patients were injected with an intravenous bolus of ⁶⁸Ga-DOTA-DiPSMA. They received serial whole-body PET scans from the time of injection up to 60 min post-injection, with a second PET/CT scanning at 120 min post-injection. In PCa patients, low-dose CT scan and whole-body PET were performed with 2 min per bed position in 40 min post-injection. Absorbed organ doses and effective doses were calculated using OLINDA/EXM. Normal organ uptake and tumor lesion uptake were measured. A lesion-by-lesion analysis was performed.

Results: ⁶⁸Ga-DOTA-DiPSMA administration was safe and well-tolerated. The kidneys received the highest absorbed dose (114.46 ± 29.28 μSv/MBq), followed by the urinary bladder wall (100.82 ± 46.22 μSv/MBq) in accordance with the expected Prostate-Specific Membrane Antigen (PSMA) renal excretion of the tracer. The mean effective dose was 19.46 ± 1.73 μSv/MBq. The SUV_max of ⁶⁸Ga-DOTA-DiPSMA PET/CT for PCa lesions, bone metastases, and lymph node metastases was 4.41 ± 2.72, 2.95 ± 1.11, and 3.26 ± 1.20, respectively.

Conclusion: Injection of ⁶⁸Ga-DOTA-DiPSMA is safe and associated with low absorbed and effective doses. ⁶⁸Ga-DOTA-DiPSMA shows favorable kinetics and imaging characteristics in patients who warrant further head-to-head comparison to validate ⁶⁸Ga-DOTA-DiPSMA as an alternative for gallium-68-labeled PSMA clinical PET. Low nonspecific uptake in normal organs of ⁶⁸Ga-DOTA-DiPSMA indicates potential radioligand therapy (RLT) application when labeled with ¹⁷⁷Lu, ⁹⁰Y, or ²²⁵Ac.

A prospective study on vulvovaginal candidiasis: multicentre molecular epidemiology of pathogenic yeasts in China

BACKGROUND

Vulvovaginal candidiasis (VVC) is frequent in women of reproductive age, but very limited data are available on the epidemiology in cases of VVC in China.

OBJECTIVES

The current study has been conducted to reveal the prevalence, species distribution of yeast causing VVC and molecular genetics of Candida albicans in China.

METHODS

Vaginal swabs were collected from 543 VVC outpatients recruited in 12 hospitals in China between September 2017 and March 2018. They were preliminarily incubated on Sabouraud dextrose agar and then positive subjects of which were then transmitted to our institute for further identification. CHROMagar™ was used to isolate Candida species, and all isolates were finally identified by DNA sequencing. Multilocus sequence typing (MLST) was used to analyse phylogenetic relationships of the various C. albicans isolates.

RESULTS

Eleven different yeast species were identified in 543 isolates, among which C. albicans (84.7%) was the most frequent, followed by C. glabrata (8.7%). We obtained 117 unique diploid sequence types from 451 clinical C. albicans isolates and 92 isolates (20.4%) belonged to a New Clade. All the strains appearing in the New Clade were from northern China and they were isolated from non-recurrent VVC.

CONCLUSIONS

Our findings suggest that C. albicans are still the main cause of VVC in China and the majority of C. albicans isolates belongs to Clade 1 with DST 79 and DST 45 being two most common. Moreover, the New Clade revealed in our study seems to be specific to northern China.

Evaluation of N, O-Benzamide difluoroboron derivatives as near-infrared fluorescent probes to detect β-amyloid and tau tangles

β-Amyloid (Aβ) plaques and Tau tangles are cognitive impairment markers vital for diagnosing and preventing Alzheimer's disease (AD). To systematically explore the relationship between the number or position of nitrogen atoms and their optical properties and biological properties, five series of new N, O-coordinated organo-difluoroboron probes were introduced as binding scaffolds for Aβ plaques and Tau tangles. These probes exhibited suitable optical properties for near-infrared (NIR) imaging. Probe 4PmNO-2 (4-((1E,3E)-4-(1,1-difluoro-1H-1λ⁴,9λ⁴-pyrimido[1,6-c][1,3,5,2]oxadiazaborinin-3-yl)buta-1,3-dien-1-yl)-N,N-dimethylaniline) displayed the excellent emission maximum (716 nm in PBS), a high quantum yield (61.4% in CH₂Cl₂), and a high affinity for synthetic Aβ_1-42 (K_d = 23.64 ± 1.08 nM) and Tau (K18) aggregates (K_d = 26.38 ± 1.29 nM), as well as for native Aβ plaques and NFTs in the brain tissue from AD patients. 4PmNO-2, with significantly enhanced fluorescence (Aβ_1-42, 136 fold; Tau (K18), 96 fold) and the highest initial brain uptake (11.57% ID/g at 2 min) in normal ICR mice, was evaluated further. In vivo NIR fluorescent imaging studies in living Aβ and Tau transgenic mice revealed that it could differentiate healthy and diseased animals. Further ex vivo fluorescent staining studies showed that 4PmNO-2 specifically bound to Aβ plaques and Tau tangles in transgenic mice. In summary, the probe 4PmNO-2 may be a useful near-infrared fluorescence (NIRF) probe for AD biomarkers.

PPA1 Promotes Breast Cancer Proliferation and Metastasis Through PI3K/AKT/GSK3β Signaling Pathway

Breast cancer is the most common malignancy among women. Inorganic pyrophosphatase 1 (PPA1) is a multifunctional protein involved in the development of several tumors. However, the role of PPA1 in breast cancer progression remains unclear. In this study, we found that PPA1 was highly expressed in breast cancer compared to its levels in normal breast tissue and that it was correlated with breast cancer clinicopathological characteristics, as well as poor survival in breast cancer patients. Silencing PPA1 restrained breast cancer proliferation and metastasis by regulating Slug-mediated epithelial-mesenchymal transition (EMT). Opposite results were observed following PPA1 overexpression. In addition, investigation of the underlying mechanism demonstrated that PPA1 ablation led to decrease phosphatidylinositol 3 kinase (PI3K) phosphorylation levels and attenuate phosphorylated AKT and glycogen synthase kinase-3 β (GSK3β), while ectopic PPA1 expression had the opposite effects. Moreover, PI3K inhibitors suppress the signaling pathways mediating the effects of PPA1 on breast cancer, resulting in tumor growth and metastasis suppression in vitro and in vivo. In summary, our results verify that PPA1 can act as an activator of PI3K/AKT/GSK3β/Slug-mediated breast cancer progression and that it is a potential therapeutic target for the inhibition of tumor progression.

P–129 Follicular extracellular vesicles of women with polycystic ovarian syndrome inhibit oocyte maturation

Study question

Does follicular extracellular vesicles of women with polycystic ovarian syndrome (PCOS-EVs) interfere with the quality of oocytes?

Summary answer

PCOS-EVs induced oxidative stress in the oocytes and inhibited oocyte maturation by increasing the abnormal mitochondria distribution and abnormal spindle rates.

What is known already

Polycystic ovarian syndrome (PCOS) is a common endocrine disorder in women of reproductive age, with a prevalence up to 10%. Women with PCOS are characterized by a clustering of features, including hyperandrogenism, polycystic ovarian morphology, and notably, anovulation. Although international guidelines recommend assisted reproduction techniques to be an effective resort for PCOS patients to conceive. However, even after overcoming ovulatory dysfunction via ovulation induction, the pregnancy outcomes of patients with PCOS were far from satisfying with lower fertilization, cleavage, and implantation rates, implicating that theoocyte quality of these patients are affected. Whereas the mechanisms have not been elucidated yet.

Study design, size, duration

Follicular fluid of PCOS patients (n = 10) and healthy controls (n = 10) were collected and used for extracellular vesicles (EVs) isolation via ultracentrifugation. Germinal vesicle (GV) oocytes collected from female ICR mice were cocultured with RIF-EVs or FER-EVs, respectively, and PBS served as a blank control. GV breakdown (GVBD) rate and maturation rate were calculated at two-hour and fourteen-hour of co-culture, respectively. Besides, oocyte mitochondria distribution, meiosis spindle morphology, and oxidative status were assessed in different groups.

Participants/materials, setting, methods

EVs were determined by western blotting, nanoparticle tracking analysis, and transmission electron microscopy. Fluorescence labeled EVs were used to visualize internalization by oocytes. Oocytes mitochondria and mitosis spindles were stained with fluorescence, and abnormal mitochondria rate or abnormal spindle rate was calculated. Reactive oxygen species (ROS) level was detected in the differently treated oocytes. Moreover, the expression of CAT, GSS, and SOD was determined in the oocytes using quantitative reverse transcription polymerase chain reaction.

Main results and the role of chance

Both PCOS-EVs and CTRL-EVs are bilayered vesicles, ranging from 100 to 150 nm, and enriched in Alix, TSG101, and CD9. EVs could be internalized by oocytes within one hour. After coculture, the GVBD rate was similar among the three groups; whereas the maturation rate was significantly decreased in the PCOS-EV group compared with CTRL-EV group or PBS group. In addition, the abnormal mitochondria distribution rate or abnormal spindle rate were significantly increased in the PCOS-EV group compared with PBS or CTRL-EV group. The ROS level was increased in the PCOS-EV group compared with CTRL-EV group, and the expression of CAT, GSS, and SOD was increased in the PCOS-EV-treated oocytes.

Limitations, reasons for caution

Our study did not identify the contents of PCOS-EVs and CTRL-EVs, and the molecular mechanisms of dysregulations induced by PCOS-EVs need further researches to investigate.

Wider implications of the findings: This work confirmed that EV-conducted cellular communication played an important role in oocyte development in women with PCOS. The dysregulation of oocytes induced by PCOS-EVs might be related to the poor oocyte quality of women with PCOS, which may provide a novel target to improve pregnancy outcomes of these patients.

Trial registration number

Not applicable

"Turn-On" Quinoline-Based Fluorescent Probe for Selective Imaging of Tau Aggregates in Alzheimer's Disease: Rational Design, Synthesis, and Molecular Docking

Tau aggregation is believed to have a strong association with the level of cognitive deficits in Alzheimer's disease (AD). Thus, optical brain imaging of tau aggregates has recently gained substantial attention as a promising tool for the early diagnosis of AD. However, selective imaging of tau aggregates is a major challenge due to sharing similar β-sheet structures with homologous Aβ fibrils. Herein, four quinoline-based fluorescent probes (Q-tau) were judiciously designed using the donor-acceptor architecture for selective imaging of tau aggregates. In particular, probe Q-tau 4 exhibited a strong intramolecular charge transfer and favorable photophysical profile, such as a large Stokes' shift and fluorescence emission wavelength of 630 nm in the presence of tau aggregates. The probe also displayed a "turn-on" fluorescence behavior toward tau fibrils with a 3.5-fold selectivity versus Aβ fibrils. In addition, Q-tau 4 exhibited nanomolar binding affinity to tau aggregates (K_d = 16.6 nM), which was 1.4 times higher than that for Aβ fibrils. The mechanism of "turn-on" fluorescence was proposed to be an environment-sensitive molecular rotor-like response. Moreover, ex vivo labeling of human AD brain sections demonstrated favorable colocalization of Q-tau 4 and the phosphorylated tau antibody, while comparable limited staining was observed with Aβ fibrils. Molecular docking was conducted to obtain insights into the tau-binding mode of the probe. Collectively, Q-tau 4 has successfully been used as a tau-specific fluorescent imaging agent with lower background interference.

Visualizing Tumors in Real Time: A Highly Sensitive PSMA Probe for NIR-II Imaging and Intraoperative Tumor Resection

Owing to the complex anatomical structure, precise resection of a tumor while maintaining adjacent tissue is a challenge in radical prostatectomy for prostate cancer (PCa). Optical imaging in near-infrared window II (NIR-II) is a promising technology for intraoperative guidance, whereas there is no available probe for PCa yet. In this article, a novel probe (PSMA-1092) bearing two prostate-specific membrane antigen (PSMA) binding motifs was developed, displaying excellent optical properties (λ_max = 1092 nm) and ultrahigh affinity (K_i = 80 pM) toward PSMA. The tumor was visualized with high resolution (tissue-to-normal tissue ratio = 7.62 ± 1.05) and clear margin by NIR-II imaging using PSMA-1092 in a mouse model. During the tumor resection, residual tumors missed by visible inspection were detected by the real-time imaging. Overall, PSMA-1092 displayed excellent performance in delineating the tumor margin and detecting residual tumors, demonstrating promising potential for precise PCa tumor resection in clinical practice.

Synthesis, Preclinical Evaluation, and First-in-Human PET Study of Quinoline-Containing PSMA Tracers with Decreased Renal Excretion

The prostate-specific membrane antigen (PSMA) is considered to be an excellent theranostic target of prostate cancer (PCa). In this study, three 18F-labeled PSMA tracers with a more lipophilic quinoline functional spacer were designed, synthesized, and evaluated based on the Glu-Ureido-Lys binding motif. The effect of structure-related lipophilic difference on distribution and excretion of these tracers in vitro and in vivo (cells, rodent, primate, and human) was investigated by comparing with [18F]DCFPyL. There is no significant correlation between the renal elimination and the lipophilicity of the tracers in all species. However, the higher the lipophilicity of tracer, the higher the radioactivity accumulation in the liver of primate and human, and the less radioactivity is to excrete to the bladder with urine. The screened tracer [18F]8c, with a Ki value of 4.58 nM, displayed notable low bladder retention and demonstrated good imaging properties in patients with PCa.

Effect of lncRNA AK023948 on rats with postmenopausal osteoporosis via PI3K/AKT signaling pathway

OBJECTIVE

To investigate the effect of long non-coding ribonucleic acid (lncRNA) AK023948 (AK0) on rats with postmenopausal osteoporosis via the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathway.

MATERIALS AND METHODS

Firstly, postmenopausal osteoporosis rat models were established to obtain osteoblasts. The phosphorylation level of AKT was analyzed by controlling the expression of AK0 gene in osteoblasts. Finally, XTT was used to analyze the proliferation of osteoblasts and the messenger ribonucleic acid (mRNA) expression level of caspase in AK0 gene knockout (KO) rat model.

RESULTS

In the bone tissue of postmenopausal osteoporosis rats, the levels of phospho-PI3K (p-PI3K), p-Akt, and p-phosphoinositide-dependent kinase-1(PDK1) were significantly decreased (p<0.05). In rat model osteoblasts, the overexpression of AK0 gene upregulated the phosphorylation level of AKT, while the interference with small interfering RNA (siRNA) in AK0 gene decreased that of AKT. Knocking out AK0 gene led to the down-regulation of phosphorylation level of AKT in cells. Moreover, if the AK0 gene was re-expressed in the KO rat model cells, the phosphorylation level of AKT was restored to a certain extent, but still lower than that after the overexpression of AK0 gene. Although the proliferation rate of osteoblasts in estrogen deficiency-related osteoporosis rats was low, the growth rate of osteoblasts with AK0 KO was remarkably lower than that in blank control group (p<0.05). It was also found that there was a certain correlation between AK0 gene and osteoblast apoptosis.

CONCLUSIONS

LncRNA AK0 can regulate the phosphorylation level of AKT in osteoblasts of rats with estrogen deficiency-related osteoporosis through the PI3K/AKT signaling pathway, thus regulating the proliferation of osteoblasts. It is speculated that lncRNA AK0 may be an important factor in regulating the PI3K/AKT signaling pathway.

Effect of lncRNA AK125437 on postmenopausal osteoporosis rats via MAPK pathway

OBJECTIVE

The aim of this study was to explore the effect of long non-coding ribonucleic acid (lncRNA) AK125437 on rats with postmenopausal osteoporosis via the mitogen-activated protein kinase (MAPK) pathway.

MATERIALS AND METHODS

A total of 36 Sprague-Dawley rats were randomly divided into three groups, including normal group, model group, and an inhibitor group, with 12 rats in each group. Only ovaries were exposed in normal group. The postmenopausal osteoporosis model was established in model group. Meanwhile, the intervention was performed with inhibitor for 3 months after modeling in inhibitor group, followed by sampling. The expression of receptor activator of nuclear factor kappa-B ligand (RANKL) was detected via immunohistochemistry. The protein expression level of phosphorylated p38 (p-p38) MAPK was determined via Western blotting (WB). Furthermore, the expression level of lncRNA AK125437 and the content of serum estradiol were determined via quantitative Polymerase Chain Reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. In addition, bone mineral density was measured using dual-energy X-ray bone mineral absorptiometer.

RESULTS

Immunohistochemistry results indicated that model group and inhibitor group had notably up-regulated positive expression level of RANKL than normal group (p<0.05), which was remarkably lower in inhibitor group than model group (p<0.05). Western blot results showed that compared with normal group, the protein expression level of p-p38 MAPK was substantially elevated in model and inhibitor groups (p<0.05). Meanwhile, the protein expression level of p-p38 MAPK was markedly lower in inhibitor group than that in model group (p<0.05). According to qPCR results, the expression level of lncRNA AK125437 was significantly up-regulated in both model group and inhibitor group compared with normal group, showing statistically significant differences (p<0.05). However, no significant differences were observed between model group and inhibitor group (p>0.05). ELISA results revealed that model group and inhibitor group had markedly lower estradiol content than normal group (p<0.05). There was no statistically significant difference in the content of estradiol between the two groups (p>0.05). According to the measurement results of bone mineral density, compared with normal group, bone mineral density was notably lower in model group and inhibitor group (p<0.05). Furthermore, it was markedly higher in inhibitor group than that of model group (p<0.05).

CONCLUSIONS

LncRNA AK125437 affects the bone mineral density of rats with postmenopausal osteoporosis by activating the MAPK pathway.

Synthesis and Evaluation of Fluorine-18 Labeled 2-Phenylquinoxaline Derivatives as Potential Tau Imaging Agents

In this study, three pairs of optically pure ¹⁸F-labeled 2-phenylquinoxaline derivatives were evaluated as Tau imaging agents for the diagnosis of Alzheimer's disease (AD). The chiral 2-fluoromethyl-1,2-ethylenediol side chain was attached to the 2-phenylquinoxaline backbone to increase hydrophilicity, thereby improving the binding affinity of the probe to tangles and their selectivity toward Tau tangles over β-amyloid plaques (Aβ). These probes displayed excellent fluorescent properties and high selectivity for tangles on brain sections from transgenic mice (rTg4510) and AD patients. Quantitative binding assays with AD homogenates showed that the probes (R)-5 and (S)-16 have a high affinity (K_i = 4.1 and 10.3 nM, respectively) and high selectivity (30.5-fold and 34.6-fold, respectively) for tangles over Aβ. The high affinity and selectivity of (R)-[¹⁸F]5 and (S)-[¹⁸F]16 for tangles were further confirmed with autoradiography on AD brain tissue in vitro. In addition, they displayed sufficient blood-brain barrier penetration (7.06% and 10.95% ID/g, respectively) and suitable brain kinetics (brain_2 min/brain_60 min = 10.1, 6.5 respectively) in normal mice. Ex vivo metabolism studies and micro-positron emission computed tomography (PET) revealed high brain biostability, good brain kinetic properties, and low nonspecific binding for (S)-[¹⁸F]16. Together, these results demonstrate that (R)-[¹⁸F]5 and (S)-[¹⁸F]16 are promising PET probes for Tau tangles imaging.

Near-Infrared Fluorescent Probes with Rotatable Polyacetylene Chains for the Detection of Amyloid-β Plaques

The plaques of accumulated β-amyloid (Aβ) in the parenchymal brain are accepted as an important biomarker for the early diagnosis of Alzheimer's disease (AD). Many near-infrared (NIR) probes, which were based on the D-π-A structure and bridged by conjugated double bonds, had been reported and displayed a high affinity to Aβ plaques. Considering the isomerization caused by the polyethylene chain, however, the conjugated polyacetylene chain is a better choice for developing new NIR Aβ probes. Hence, in this report, a new series of NIR probes with naphthyl or phenyl rings and different numbers of conjugated triple bonds were designed, synthesized, and evaluated as NIR probes for Aβ plaques. Upon interaction with Aβ aggregates, these probes displayed a significant increase in fluorescence intensity (45- to 360-fold) and a high to moderate affinity (6.05-56.62 nM). Among them, probe 22b displayed excellent fluorescent properties with a 183-fold increase in fluorescence intensity and an emission maximum at 650 nm after incubated with Aβ aggregates. Furthermore, 22b had a high affinity to Aβ aggregates (K_d = 12.96 nM) and could efficiently detect the Aβ plaques in brain sections from both transgenic mice and AD patients in vitro. In summary, this work may lead to a new direction in the development of novel NIR probes for the detection of Aβ plaques.

18F-labeled 2-phenylbenzoheterocycles with chiral dihydroxyl side chains as β-amyloid imaging probes

This study reported the design, synthesis and bio-evaluation of 2-phenylbenzoheterocycles with chiral dihydroxyl side chains as β-amyloid (Aβ) imaging probes. This strategy of introducing two hydroxyls offered a simplified method for effectively reducing the lipophilicity. The probes (R, S)/(S, R)-14-15 with benzothiazole scaffold displayed good binding affinities toward Aβ_1-42 aggregates with K_i values ranging from 47.63 to 56.28 nM. Further biological studies shown that (R, S)/(S, R)-[¹⁸F]14 have no obvious chirality-related discrepancy in binding ability and mice bio-distribution, while (S, R)-enantiomer exhibited slightly faster brain washout rate than (R, S)-enantiomer. Compared to the FDA approved [¹⁸F]Florbetapir and the fluoro-peglated 2-phenylbenzothiazole derivatives, (S, R)-[¹⁸F]14 displayed improved brain kinetics (6.40% ID/g at 2 min, brain_{2 min}/brain_{60 min} = 7.80) that is favorable for further application. In vitro autoradiography studies validated its high affinity and specificity to Aβ plaques. Overall, (S, R)-[¹⁸F]14 deserved further detailed study as a potential PET imaging probe for AD early diagnosis.

MiRNA-98-5p inhibits the progression of osteosarcoma by regulating cell cycle via targeting CDC25A expression

OBJECTIVE

The aim of this study was to elucidate the exact role of microRNA-98-5p (miRNA-98-5p) in the progression of osteosarcoma and to explore its potential mechanism.

PATIENTS AND METHODS

The expression levels of miRNA-98-5p and cell division cycle 25 (CDC25A) in osteosarcoma tissues and cell lines were determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Meanwhile, the correlation between expressions of miRNA-98-5p and CDC25A and the survival of osteosarcoma patients was analyzed. After altering miRNA-98-5p and CDC25A expressions by liposome transfection, the expression levels of CDC25A, ki67, Cyclin D1, p21, BCL2-Associated X (BAX), B-cell lymphoma-2 (BCL-2) and BCL-XL in osteosarcoma cells were detected. Subsequently, potential binding sites between miRNA-98-5p and CDC25A were predicted and further verified by miRanda and Dual-Luciferase reporter gene assay, respectively. Regulatory effects of miRNA-98-5p and CDC25A on the migratory ability of osteosarcoma cells were evaluated by transwell assay. Moreover, nude mice were subcutaneously implanted with MG-63 cells over-expressing miRNA-98-5p or negative control. In addition, the functions of miRNA-98-5p and CDC25A in tumor-bearing nude mice were explored in vivo.

RESULTS

MiRNA-98-5p was lowly expressed in osteosarcoma tissues and cell lines, whereas CDC25A was highly expressed. Survival analysis showed that the survival of osteosarcoma patients with low-level of miRNA-98-5p or high-level of CDC25A was significantly worse. Besides, a negative correlation was identified between miRNA-98-5p and CDC25A. Subsequent experiments revealed that miRNA-98-5p significantly inhibited cell cycle progression and migratory potential, whereas induced the apoptosis of osteosarcoma cells by down-regulating CDC25A.

CONCLUSIONS

MiRNA-98-5p is lowly expressed, while CDC25A is highly expressed in osteosarcoma. Furthermore, miRNA-98-5p regulates cell cycle progression by down-regulating CDC25A, thus inhibiting the progression of osteosarcoma.

Discovery of Diphenoxy Derivatives with Flexible Linkers as Ligands for β-Amyloid Plaques

The highly rigid and planar scaffolds with π-conjugated systems have been widely considered to be indispensable for β-amyloid (Aβ) binding ligands. In this study, a library of diphenoxy compounds with different types of more flexible linkers as Aβ ligands were synthesized and evaluated. Most of them displayed good affinity (K_i < 100 nM) for Aβ_1-42 aggregates, and some ligands even showed values of K_i less than 10 nM. Structure-activity relationship analysis revealed that modification on the linkers or substituents tolerated great flexibility, which challenged the long-held belief that rigid and planar structures are exclusively favored for Aβ binding. Three ligands were labeled by iodine-125, and they exhibited good properties in vitro and in vivo, which further supported that this flexible scaffold was potential and promising for the development of Aβ imaging agents.

Effect of age and parity on maternal diastolic function in middle trimester pregnant women with normal left ventricular ejection fraction and potential link of diastolic function to pre-eclampsia

Background

It has been suggested that maternal cardiac adaptations during pregnancy differ between nulliparous and multipara women and also vary according to the age. Impaired cardiac function precedes pre-eclampsia.

Purpose

To evaluate effect of age and parity on maternal cardiac diastolic function in middle trimester among pregnant women with normal left ventricular ejection fraction as well as correlation between impaired diastolic function and pre-eclampsia.

Methods

Pregnant women with singleton pregnancies carried from 13 weeks to 20 weeks and left ventricular ejection fraction (LVEF) ≥50% were identified. Diastolic function parameters were assessed using transthoracic echocardiography. Pre-eclampsia was identified from medical records.

Results

376 pregnant women were included (median age: 30 years; median gestational age: 14 weeks; 171 multiparous women). LVEF was 66%. Impaired cardiac diastolic function was seen in 7.8% of pregnant women &lt;35 years compared with 28.6% of those ≥35 years (p=0.000). ROC curve showed women with maternal age over 32 began to have a higher rate of impaired cardiac diastolic function (AUC=0.704, p=0.000, sensitivity=54.5%, specificity=75.3%). There was no difference in diastolic function indices between maternal women grouped by parity. After adjustment for confounders, maternal age can be independent effect factor of Em declined (P&lt;0.05). Em&lt;13cm/s was significantly associated with pre-eclampsia occurrence (HR 8.56; 95% CI: 3.40–21.57) after adjusting for the confounders.

Conclusion

Maternal age is an independent impact factor for diastolic function decline. There is no difference in cardiac diastolic function between nullipara and multipara. Pre-eclampsia occurrence is significantly higher in patients with diastolic function decline at mid-gestation. The utility of risk stratification using diastolic function at mid-gestation may improve the survival outcomes of pregnant women.

Association between Em and PE risk

Funding Acknowledgement

Type of funding source: None

Immunocyte density in parathyroid carcinoma is correlated with disease relapse

PURPOSE

Parathyroid carcinoma (PC) is an endocrine malignancy with a poor prognosis. The tumour immune microenvironment is a critical factor influencing the outcomes of multiple cancer types. However, knowledge of the immune microenvironment in PC remains limited.

METHODS

The intratumoural density of immunocytes and the Ki-67 index were evaluated immunohistochemically in 51 PC patient samples and were compared with clinicopathological features and parafibromin staining results. The Kaplan-Meier method and Cox proportional hazards analysis were used to estimate the effects of these variables on clinical outcomes.

RESULTS

Intratumoural immunocyte density was not correlated with age, gender, urolithiasis, or palpation of a neck mass. The Ki-67 index was correlated with the intratumoural density of CD3⁺ cells (P = 0.022) and CD8⁺ cells (P = 0.021) and serum calcium levels (P = 0.022). In the intratumoural area of primary foci, Kaplan-Meier method showed that the risk factors associated with recurrence/metastasis were a low density of CD3⁺ (P = 0.017), CD8⁺ (P = 0.019) and CD45⁺ cells (P = 0.047), a high density of CD163⁺ cells (P = 0.003) and a high Ki-67 index (P = 0.004). Cox regression multivariate analysis revealed that CD163⁺ cell density (hazard ratio (HR) 16.19, 95% confidence interval (CI) 1.99-131.66; P = 0.009) and CD8⁺ cell density (HR 0.13, 95% CI 0.02-0.76, P = 0.024) were independent factors associated with PC relapse.

CONCLUSION

The immune microenvironment is an important factor influencing the relapse of PC. The intratumoural density of CD3⁺, CD8⁺, CD45⁺, and CD163⁺ immunocytes was correlated with disease-free survival (DFS) in patients with PC. Immunotherapy based on T lymphocytes or tumour-associated macrophages may be a promising treatment strategy.

Cosmic-ray antinuclei as messengers of new physics: status and outlook for the new decade

The precise measurement of cosmic-ray antinuclei serves as an important means for identifying the nature of dark matter and other new astrophysical phenomena, and could be used with other cosmic-ray species to understand cosmic-ray production and propagation in the Galaxy. For instance, low-energy antideuterons would provide a "smoking gun" signature of dark matter annihilation or decay, essentially free of astrophysical background. Studies in recent years have emphasized that models for cosmic-ray antideuterons must be considered together with the abundant cosmic antiprotons and any potential observation of antihelium. Therefore, a second dedicated Antideuteron Workshop was organized at UCLA in March 2019, bringing together a community of theorists and experimentalists to review the status of current observations of cosmic-ray antinuclei, the theoretical work towards understanding these signatures, and the potential of upcoming measurements to illuminate ongoing controversies. This review aims to synthesize this recent work and present implications for the upcoming decade of antinuclei observations and searches. This includes discussion of a possible dark matter signature in the AMS-02 antiproton spectrum, the most recent limits from BESS Polar-II on the cosmic antideuteron flux, and reports of candidate antihelium events by AMS-02; recent collider and cosmic-ray measurements relevant for antinuclei production models; the state of cosmic-ray transport models in light of AMS-02 and Voyager data; and the prospects for upcoming experiments, such as GAPS. This provides a roadmap for progress on cosmic antinuclei signatures of dark matter in the coming years.