[Effect of HBV DNA load on the safety and prognosis of systematic therapy in advanced hepatocellular carcinoma]

Objective: To study the effect of hepatitis B virus (HBV) infection on the occurrence of liver damage, HBV reactivation (HBVr) and the influence of HBVr on the prognosis of patients with advanced hepatocellular carcinoma (HCC) receiving systemic therapy. Methods: The clinical data of 403 patients with HBV-related HCC at the Department of Infectious Diseases, The Third Affiliated Hospital of Sun Yat-Sen University et al, from July 2018 to December 2020 were collected. The incidence of liver damage and HBVr during systematic therapy, and the influence of HBVr on survival prognosis were analyzed. Results: Of the 403 patients, 89.1% were male (n=359), with a median age of 51 years (51.5±12.1). Before propensity score matching (PSM), the proportion of patients with cirrhosis, TNM and advanced BCLC stage was higher in high HBV-DNA (baseline HBV-DNA>1000 U/ml, n=147) group comparing with the low HBV-DNA (baseline HBV DNA≤1000 u/ml, n=256) group (P<0.05). There was no significant difference in baseline indexes between the two groups after PSM. In 290 patients after PSM, there was no significant difference in the incidence of liver damage and HBVr between high HBV-DNA group and low HBV-DNA group (P>0.05). Survival analysis was performed on 169 patients with survival data, the median overall survival (OS) was found to be 11.49 months (95%CI: 7.77-12.89) and 16.65 months (95%CI: 10.54-21.99, P=0.008) in the high and low HBV-DNA groups, respectively. And median progression-free survival (PFS) was 7.41 months (95%CI: 5.06-8.67) and 10.55 months (95%CI: 6.72-13.54, P=0.038), respectively, with a statistically significant difference. There were no differences in overall survival (OS) and progression-free survival (PFS) between patients with and without HBVr and those with or without liver damage (P>0.05). Conclusions: HBV-DNA levels above 1 000 U/ml before systemic therapy do not increase the risk of liver damage or HBVr during systemic therapy in patients with HBV-related hepatocellular carcinoma, and such patients can safely receive systemic therapy.

Structural and mechanistic insights into disease-associated endolysosomal exonucleases PLD3 and PLD4

Endolysosomal exonucleases PLD3 and PLD4 (phospholipases D3 and D4) are associated with autoinflammatory and autoimmune diseases. We report structures of these enzymes, and the molecular basis of their catalysis. The structures reveal an intra-chain dimer topology forming a basic active site at the interface. Like other PLD superfamily members, PLD3 and PLD4 carry HxKxxxxD/E motifs and participate in phosphodiester-bond cleavage. The enzymes digest ssDNA and ssRNA in a 5'-to-3' manner and are blocked by 5'-phosphorylation. We captured structures in apo, intermediate, and product states and revealed a "link-and-release" two-step catalysis. We also unexpectedly demonstrated phosphatase activity via a covalent 3-phosphohistidine intermediate. PLD4 contains an extra hydrophobic clamp that stabilizes substrate and could affect oligonucleotide substrate preference and product release. Biochemical and structural analysis of disease-associated mutants of PLD3/4 demonstrated reduced enzyme activity or thermostability and the possible basis for disease association. Furthermore, these findings provide insight into therapeutic design.

[Clinical and laboratory features of SF3B1-mutated myeloproliferative neoplasms]

Objective: To explore the clinical and laboratory characteristics of SF3B1 gene mutations in myeloproliferative neoplasms (MPN) patients. Methods: The clinical data of 273 MPN patients who were diagnosed MPN and treated in the Second Hospital of Tianjin Medical University from November 2017 to March 2023 were retrospectively analyzed. There were 133 males and 140 females, with a median age M(Q1,Q3)of 56(46, 67) years. The molecular biology and cytogenetic characteristics were detected by second-generation sequencing (NGS) and R+G banding techniques, and the clinical and laboratory characteristics of patients with SF3B1 gene mutation were analyzed. Results: SF3B1 gene mutations were found in 13 patients (4.8%, 13/273).The types of SF3B1 mutations included missense (92.3%, 12/13) and nonsense mutations (7.7%, 1/13).Compared to the non-mutant cohort, patients in SF3B1 mutant cohort had older ages [68(51, 76) vs 56(45, 66)years,P=0.025], higher proportion of splenomegaly [46.2%(6/13) vs 15.8%(41/259),P=0.014]and secondary tumor [23.1%(3/13)vs 3.8%(10/260), P=0.018]with higher proportion of bone marrow blast [0.5%(0, 1.5%) vs 0(0, 0.5%),P=0.002] and lower hemoglobin[(104±36) vs (137±40) g/L,P=0.004] and hematocrit [31%(22%, 40%) vs 41%(35%, 52%),P=0.003]. All of the 10 patients in the SF3B1 mutant cohort whose ring sideroblast (RS) could be evaluated showed no RS formation. The overall survival, thrombosis-free survival and leukemia free survival of MPN patients in SF3B1 mutant cohort were 4.0 (2.0, 6.0), 2.0 (0.5, 4.5) and 4.0 (2.0, 6.0) years, respectively, while patients in the non-mutant cohort were 6.0 (3.0, 10.0), 5.0 (1.0, 8.0), 6.0 (3.0, 10.0) years, respectively, there were no statistical significance between two groups (Z=3.69, 1.66, 2.05, all P>0.05).The secondary tumor free survival of SF3B1 mutant cohort patients was 4.0 (2.0, 6.0) years, which was lower than that of non-mutant cohort patients [5.5 (3.0, 10.0) years, Z=18.18, P<0.001). Conclusions: MPN patients with SF3B1 gene mutations are older, more prone to splenomegaly and secondary tumors. They also have a higher proportion of bone marrow blast, lower hemoglobin and hematocrit, and show no RS formation.

Structural and mechanistic insights into disease-associated endolysosomal exonucleases PLD3 and PLD4

Endolysosomal exonucleases PLD3 and PLD4 (phospholipases D3 and D4) are associated with autoinflammatory and autoimmune diseases. We report structures of these enzymes, and the molecular basis of their catalysis. The structures reveal an intra-chain dimer topology forming a basic active site at the interface. Like other PLD superfamily members, PLD3 and PLD4 carry HxKxxxxD/E motifs and participate in phosphodiester-bond cleavage. The enzymes digest ssDNA and ssRNA in a 5'-to-3' manner and are blocked by 5'-phosphorylation. We captured structures in apo, intermediate, and product states and revealed a 'link-and-release' two-step catalysis. We also unexpectedly demonstrated phosphatase activity via a covalent 3' phosphistidine intermediate. PLD4 contains an extra hydrophobic clamp that stabilizes substrate and could affect oligonucleotide substrate preference and product release. Biochemical and structural analysis of disease-associated mutants of PLD3/4 demonstrated reduced enzyme activity or thermostability and the possible basis for disease association. Furthermore, these findings provide insight into therapeutic design.

Endoscopic Ultrasonography-Derived Maximum Tumor Thickness and Tumor Shrinkage Rate as Independent Prognostic Factors in Locally Advanced Esophageal Squamous Cell Carcinoma after Neoadjuvant Chemoradiotherapy

PURPOSE/OBJECTIVE(S)

Neoadjuvant chemoradiotherapy (NCRT) is increasingly used in patients with locally advanced esophageal squamous cell carcinoma (LA-ESCC). Endoscopic ultrasonography (EUS)-derived maximum tumor thickness (MTT) before and after standard NCRT for LA-ESCC indicates treatment response. However, the accuracy of predicting long-term survival remains uncertain. This study aimed to investigate the association between EUS-derived MTT pre- and post-NCRT and tumor shrinkage rate as well as long-term survival in patients with LA-ESCC receiving NCRT.

MATERIALS/METHODS

We retrospectively enrolled patients with LA-ESCC who underwent EUS examination pre- and post-NCRT from 2017 to 2021. MTT was measured using EUS. Tumor shrinkage rate was the ratio of the difference between pre- and post-MTT to pre-MTT. The most fitted cut-off value defining the EUS response was determined by the receiver operating characteristic curve. Univariate and multivariate Cox regression analyses and Kaplan-Meier (KM) curves were used to calculate overall survival (OS) and progression-free survival (PFS). Data from another center were also used for external validation testing.

RESULTS

The median follow-up period was 30.6 months.230 patients with LA-ESCC who underwent EUS pre- or post-NCRT were enrolled. Of the patients, 178 completed the first EUS pre-NCRT and obtained pre-MTT, 200 completed the re-examined EUS post-NCRT and obtained post-MTT, and 148 completed both EUS and achieved tumor shrinkage. In the whole group the 1-year and 3-year OS rates were 93.9% and 67.9%, and PFS rates were 77.7% and 54.1%, respectively. Thinner post-MTT (≤8.8 mm) and EUS-responders (tumor shrinkage rate≥52%) were independently associated with better OS. The result of EUS-respond was an independent prognostic factor could be confirmed in the external validation group. Among LA-ESCC patients with initial ultrasonic T2-3 staging and T4 staging, no statistically differences were observed between the responder and non-responder groups (P = 0.082; P = 0.190).

CONCLUSION

EUS-derived MTT and tumor shrinkage post-NCRT are independent prognostic factors for long-term survival and may be an alternative method for evaluating tumor response in patients with LA-ESCC after NCRT. Initial tumor infiltration beyond esophageal adventitial layer on ultrasound effect could not, however, predict the long-term prognosis.

Hippocampus shapes cortical sensory output and novelty coding through a direct feedback circuit

To extract behaviorally relevant information from our surroundings, our brains constantly integrate and compare incoming sensory information with those stored as memories. Cortico-hippocampal interactions could mediate such interplay between sensory processing and memory recall1-4 but this remains to be demonstrated. Recent work parsing entorhinal cortex-to-hippocampus circuitry show its role in episodic memory formation5-7 and spatial navigation8. However, the organization and function of the hippocampus-to-cortex back-projection circuit remains uncharted. We combined circuit mapping, physiology and behavior with optogenetic manipulations, and computational modeling to reveal how hippocampal feedback modulates cortical sensory activity and behavioral output. Here we show a new direct hippocampal projection to entorhinal cortex layer 2/3, the very layer that projects multisensory input to the hippocampus. Our finding challenges the canonical cortico-hippocampal circuit model where hippocampal feedback only reaches entorhinal cortex layer 2/3 indirectly via layer 5. This direct hippocampal input integrates with cortical sensory inputs in layer 2/3 neurons to drive their plasticity and spike output, and provides an important novelty signal during behavior for coding objects and their locations. Through the sensory-memory feedback loop, hippocampus can update real-time cortical sensory processing, efficiently and iteratively, thereby imparting the salient context for adaptive learned behaviors with new experiences.

Broadening a SARS-CoV-1-neutralizing antibody for potent SARS-CoV-2 neutralization through directed evolution

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscores the need for strategies to rapidly develop neutralizing monoclonal antibodies that can function as prophylactic and therapeutic agents and to help guide vaccine design. Here, we demonstrate that engineering approaches can be used to refocus an existing antibody that neutralizes one virus but not a related virus. Through a rapid affinity maturation strategy, we engineered CR3022, a SARS-CoV-1-neutralizing antibody, to bind to the receptor binding domain of SARS-CoV-2 with >1000-fold increased affinity. The engineered CR3022 neutralized SARS-CoV-2 and provided prophylactic protection from viral challenge in a small animal model of SARS-CoV-2 infection. Deep sequencing throughout the engineering process paired with crystallographic analysis of engineered CR3022 elucidated the molecular mechanisms by which the antibody can accommodate sequence differences in the epitopes between SARS-CoV-1 and SARS-CoV-2. This workflow provides a blueprint for the rapid broadening of neutralization of an antibody from one virus to closely related but resistant viruses.

[Effects of ppk1 deletion on the drug susceptibility of uropathogenic Escherichia coli producing ESBLs]

To investigate the effect and the mechanism of ppk1 gene deletion on the drug susceptibility of uropathogenic Escherichia coli producing extended-spectrum beta-lactamases (ESBLs-UPEC). The study was an experimental study. From March to April 2021, a strain of ESBLs-UPEC (genotype was TEM combined with CTX-M-14) named as UE210113, was isolated from urine sample of the patient with urinary tract infection in the Laboratory Department of Guangzhou Eighth People's Hospital, meanwhile its ppk1 gene knock-out strain Δpk1 and complemented strain Δpk1-C were constructed by suicide plasmid homologous recombination technique, which was used to study the effect of ppk1 gene on ESBLs-UPEC drug sensitivity and its mechanism. The drug susceptibility of UE210113, Δpk1, and Δpk1-C were measured by Vitek2 Compact System and broth microdilution method. The quantitative expression of ESBLs, outer membrane protein and multidrug efflux systems encoding genes of UE210113, Δpk1 and Δpk1-C were performed by using qRT-PCR analysis. By using two independent sample Mann-Whitney U test, the drug susceptibility results showed that, compared with UE210113 strain, the sensitivities of Δpk1 to ceftazidime, cefepime, tobramycin, minocycline and cotrimoxazole were enhanced (Z=-2.121,P<0.05;Z=-2.236,P<0.05;Z=-2.236,P<0.05;Z=-2.121,P<0.05), and the drug susceptibility of Δpk1-C restored to the same as which of UE210113 (Z=0,P>0.05). The expression levels of ESBLs-enconding genes blaTEM and blaCTX-M-14 in Δpk1 were significantly down-regulated compared with UE210113, but the expression was not restored in Δpk1-C. The expression of outer membrane protein gene omp F in Δpk1 was significantly up-regulated, while the expression of omp A and omp C were down-regulated. The results showed that the expression of multidrug efflux systems encoding genes tol C, mdt A and mdtG were down-regulated in Δpk1 compared with UE210113. The expression of all of the outer membrane protein genes and the multidrug efflux systems genes were restored in Δpk1-C. In conclusion,the lost of ppk1 gene can affect the expression of the outer membrane protein and multidrug efflux systems encoding genes of ESBLs-UPEC, which increase the sensitivity of ESBLs-UPEC to various drugs.

[Puerarin alleviates lipopolysaccharide-induced acute kidney injury in mice by modulating the SIRT1/NF-κB pathway]

OBJECTIVE

To investigate the role of the SIRT1/NF-κB pathway in mediating the effect of puerarin against lipopolysaccharide (LPS)-induced acute kidney injury (AKI).

METHODS

Fifteen BALB/C mice were randomized into control group, LPS group and puerarin treatment group, and in the latter two groups, the mice were given an intraperitoneal injection of LPS (5 mg/kg), followed by daily injection of normal saline for 3 days or injection of puerarin (25 mg/kg) given 1 h later and then on a daily basis for 3 days. On day 5 after modeling, the kidney tissues were taken for histological observation and detection of cell apoptosis. The renal function indexes including urea nitrogen (BUN), serum creatinine (Scr) and kidney injury molecule 1 (KIM-1) and the levels of tumor necrosis factor (TNF-α) and interleukin 1β (IL-1β) were measured, and the expressions of SIRT1 and NF-κB-p65(acetyl K310) in the renal tissues were detected.

RESULTS

Intraperitoneal injection of LPS caused obvious glomerular capillary dilatation, hyperemia, renal interstitial edema, and renal tubular epithelial cell swelling and deformation in the mice. The mouse models of LPS-induced AKI also showed significantly increased renal tubular injury score and renal cell apoptosis (P < 0.01) with increased serum levels of BUN, Scr, KIM-1, TNF-α and IL-1β (P < 0.01), enhanced renal expressions of TNF-α, IL-1β and NF-κB p65(acetyl K310) (P < 0.01) and lowered renal expression of SIRT1 (P < 0.05). Treatment with puerarin effectively alleviated LPS-induced renal interstitial edema and renal tubular epithelial cell shedding, lowered renal tubular injury score (P < 0.01) and renal cell apoptosis rate (P < 0.01), and decreased serum levels of BUN, Scr, KIM, TNF-α and IL-1β (P < 0.01). Puerarin treatment significantly reduced TNF-α, IL-1β and NF-κB p65 (acetyl K310) expression in the renal tissue (P < 0.05) and increased SIRT1 expression by 17% (P < 0.05) in the mouse models.

CONCLUSION

Puerarin can effectively alleviate LPS-induced AKI in mice possibly by modulating the SIRT1/NF-κB signaling pathway.

Early adjunctive diagnostic value of contrast-enhanced ultrasound-related quantitative parameter and its relationship with micro-perfusion of nontraumatic necrosis of femoral head

OBJECTIVE

The aim of this study is to explore the early diagnostic value of contrast-enhanced ultrasound (CEUS)-related quantitative parameter and its relationship with the micro-perfusion of nontraumatic necrosis of the femoral head.

PATIENTS AND METHODS

According to the random and double-blind method, the patients with non-traumatic femoral head necrosis diagnosed and treated in our hospital from July 2019 to January 2022 were selected as the subjects (the research group). According to the staging of the International Society of Bone Circulation for Femoral Head Necrosis, 89 patients with stage Ⅱ and Ⅲ A were included (39 patients with stage Ⅱ and 50 patients with stage Ⅲ A). 25 patients who conducted physical examination in our hospital during the same time were taken as the control group. Quantitative parameters of CEUS were analyzed. The content of serum vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) were evaluated. The relationship among the quantitative parameters of CEUS, the expression of VEGF and BMP-2 in serum and the patient's condition, and the value for assisting the early diagnosis of nontraumatic femoral head necrosis were analyzed.

RESULTS

The body mass, body mass index (BMI), blood lipid, and cholesterol levels were much higher in the research group than in the control group (p < 0.05). The research group had a markedly higher slope of ascending branch (AS), strength enhancement index (EI), and VEGF and obviously lower decay slope (DS), mean transit time (MTT), and time to peak (TTP) than the control group (p < 0.05). In the research group, compared to stage Ⅱ, the levels of AS, EI, and VEGF in stage Ⅲ A patients were memorably higher, and the levels of DS, MTT, TTP and BMP-2 were dramatically lower (p < 0.05). Pearson's correlation test showed that AS, EI, and VEGF were positively correlated with the patients' condition, while DS, MTT, TTP and BMP-2 were negatively correlated with the patients' condition (p < 0.05). The receiver operating characteristic (ROC) curve analysis showed that the diagnostic area under the curve (AUC) of quantitative parameters of CEUS was 0.961, with sensitivity and specificity of 88.0% and 97.4%, respectively. The AUC of the combined detection of VEGF and BMP-2 was 0.945 with sensitivity and specificity of 82.3% and 87.5%, respectively, and the combined detection had a high diagnostic value (p < 0.05).

CONCLUSIONS

The quantitative parameters of CEUS were of great value in the early diagnosis of nontraumatic necrosis of the femoral head with microvascular perfusion and the patients' condition, and provided a reference for the clinical treatment of non-traumatic necrosis of the femoral head. These parameters were expected to be useful indicators for judging the efficacy before and after treatment.

Broadly neutralizing antibodies targeting a conserved silent face of spike RBD resist extreme SARS-CoV-2 antigenic drift

Developing broad coronavirus vaccines requires identifying and understanding the molecular basis of broadly neutralizing antibody (bnAb) spike sites. In our previous work, we identified sarbecovirus spike RBD group 1 and 2 bnAbs. We have now shown that many of these bnAbs can still neutralize highly mutated SARS-CoV-2 variants, including the XBB.1.5. Structural studies revealed that group 1 bnAbs use recurrent germline-encoded CDRH3 features to interact with a conserved RBD region that overlaps with class 4 bnAb site. Group 2 bnAbs recognize a less well-characterized "site V" on the RBD and destabilize spike trimer. The site V has remained largely unchanged in SARS-CoV-2 variants and is highly conserved across diverse sarbecoviruses, making it a promising target for broad coronavirus vaccine development. Our findings suggest that targeted vaccine strategies may be needed to induce effective B cell responses to escape resistant subdominant spike RBD bnAb sites.

[High expression of MYH9 inhibits apoptosis of non-small cell lung cancer cells through activating the AKT/c-Myc pathway]

OBJECTIVE

To investigate the role of myosin heavy chain 9 (MYH9) in regulation of cell proliferation, apoptosis, and cisplatin sensitivity of non-small cell lung cancer (NSCLC).

METHODS

Six NSCLC cell lines (A549, H1299, H1975, SPCA1, H322, and H460) and a normal bronchial epithelial cell line (16HBE) were examined for MYH9 expression using Western blotting. Immunohistochemical staining was used to detect MYH9 expression in a tissue microarray containing 49 NSCLC and 43 adjacent tissue specimens. MYH9 knockout cell models were established in H1299 and H1975 cells using CRISPR/Cas9 technology, and the changes in cell proliferation cell were assessed using cell counting kit-8 (CCK8) and clone formation assays; Western blotting and flow cytometry were used to detect apoptosis of the cell models, and cisplatin sensitivity of the cells was evaluated using IC50 assay. The growth of tumor xenografts derived from NSCLC with or without MYH9 knockout was observed in nude mice.

RESULTS

MYH9 expression was significantly upregulated in NSCLC (P < 0.001), and the patients with high MYH9 expression had a significantly shorter survival time (P=0.023). In cultured NSCLC cells, MYH9 knockout obviously inhibited cell proliferation (P < 0.001), promoted cell apoptosis (P < 0.05), and increased their chemosensitivity of cisplatin. In the tumor-bearing mouse models, the NSCLC cells with MYH9 knockout showed a significantly lower growth rate (P < 0.05). Western blotting showed that MYH9 knockout inactivated the AKT/c- Myc axis (P < 0.05) to inhibit the expression of BCL2- like protein 1 (P < 0.05), promoted the expression of BH3- interacting domain death agonist and the apoptosis regulator BAX (P < 0.05), and activated apoptosis-related proteins caspase-3 and caspase-9 (P < 0.05).

CONCLUSION

High expression of MYH9 contributes to NSCLC progression by inhibiting cell apoptosis via activating the AKT/c-Myc axis.

The effects of aging and frailty on inpatient glycemic control by continuous glucose monitoring in patients with type 2 diabetes

BACKGROUND

Older adults with diabetes in the hospital are generally managed similarly to younger adults, however, it is unknown if the degree of frailty can affect glucose control among hospitalized patients.

METHODS

We examined glycemic parameters derived from continuous glucose monitoring (CGM) in older adults with type 2 diabetes and frailty who were hospitalized in non-acute settings. Data was pooled from 3 prospective studies using CGM including 97 patients wearing Libre CGM sensors and 166 patients wearing Dexcom G6 CGM. Glycemic parameters (time in range (TIR) 70-180; time below range (TBR) <70 and 54 mg/dl) by CGM were compared between 103 older adults ≥60 years and 168 younger adults <60 years. Frailty was assessed using validated laboratory and vital signs frailty index FI-LAB (n = 85), and its effect on hypoglycemia risk was studied.

RESULTS

Older adults, as compared to younger adults, had significantly lower admission HbA1c (8.76% ± 1.82 vs. 10.25% ± 2.29, p < 0.001), blood glucose (203.89 ± 88.65 vs. 247.86 ± 124.17 mg/dl, p = 0.003), mean daily BG (173.9 ± 41.3 vs. 183.6 ± 45.0 mg/dl, p = 0.07) and higher percent TIR 70-180 mg/dl (59.0 ± 25.6% vs. 51.0 ± 26.1%, p = 0.02) during hospital stay. There was no difference in hypoglycemia occurrence between older and younger adults. Higher FI-LAB score was associated with higher % CGM < 70 mg/dl (0.204) and % CGM < 54 mg/dl (0.217).

CONCLUSION

Older adults with type 2 diabetes have better glycemic control prior to admission and during hospital stay compared to younger adults. Frailty is associated with longer presence of hypoglycemia in non-acute hospital settings.

Predictive value of endometrial receptivity evaluated by three-dimensional ultrasound in ectopic pregnancy after in vitro fertilization-embryo transfer

OBJECTIVE

The aim of this study was to use three-dimensional (3D) ultrasound to detect ultrasound parameters related to the uterine artery and endometrium, evaluate endometrial receptivity, and investigate the predictive value of each parameter for ectopic pregnancy (EP) after in vitro fertilization-embryo transfer (IVF-ET).

PATIENTS AND METHODS

Fifty-seven cases of pregnancy following IVF-ET in our institution were collected and split into EP and intrauterine pregnancy (IP) groups based on the location of pregnancy, with 27 cases in EP and 30 cases in IP. Endometrial thickness, type, volume, endometrial blood flow parameters, and uterine artery blood flow parameters were all measured one day before transplantation in both groups, and the differences between the two groups were examined.

RESULTS

There were differences in endometrial blood flow typing between the two groups, with type III endometrium accounting for the highest proportion in both; the uterine spiral artery pulsatility index PI was significantly higher in the EP group than in the IP group; there were no statistical differences in uterine volume, uterine artery resistance index mRI, or uterine artery resistance index S/D between the two groups; there were no statistical differences in uterine volume, or uterine artery.

CONCLUSIONS

Intracavitary 3D ultrasound can assess endometrial tolerance and may predict pregnancy outcome after IVF-ET.

Broadly neutralizing anti-S2 antibodies protect against all three human betacoronaviruses that cause deadly disease

Pan-betacoronavirus neutralizing antibodies may hold the key to developing broadly protective vaccines against novel pandemic coronaviruses and to more effectively respond to SARS-CoV-2 variants. The emergence of Omicron and subvariants of SARS-CoV-2 illustrates the limitations of solely targeting the receptor-binding domain (RBD) of the spike (S) protein. Here, we isolated a large panel of broadly neutralizing antibodies (bnAbs) from SARS-CoV-2 recovered-vaccinated donors, which targets a conserved S2 region in the betacoronavirus spike fusion machinery. Select bnAbs showed broad in vivo protection against all three deadly betacoronaviruses, SARS-CoV-1, SARS-CoV-2, and MERS-CoV, which have spilled over into humans in the past two decades. Structural studies of these bnAbs delineated the molecular basis for their broad reactivity and revealed common antibody features targetable by broad vaccination strategies. These bnAbs provide new insights and opportunities for antibody-based interventions and for developing pan-betacoronavirus vaccines.

Assessment of healthcare quality among village clinicians in rural China: the role of internal work motivation

INTRODUCTION

The quality of primary care is important for health outcomes among residents in China. There is evidence that internal work motivation improves the quality of healthcare provided by clinicians. However, few empirical studies have examined the relationship between internal work motivation and clinical performance among village clinicians in rural China. This study was performed to evaluate healthcare quality among village clinicians, then explore its relationships with internal work motivation among those clinicians.

METHODS

We collected survey data using a standardised patient method and a structured questionnaire. We observed 225 interactions between standardised patients and village clinicians from 21 counties in three provinces. We used logistic regression models to analyse the relationships between work motivation and healthcare quality, then conducted heterogeneity analysis.

RESULTS

Healthcare quality among village clinicians was generally low. There was a significantly positive correlation between internal work motivation and healthcare quality among village clinicians (P<0.1). Additionally, the positive effect of internal work motivation on healthcare quality was strongest among clinicians who received financial incentives and had a lighter workload (fewer patients per month) [P<0.1].

CONCLUSION

Healthcare quality among village clinicians requires urgent improvement. We recommend implementing financial incentives to stimulate internal work motivation among village clinicians, thus improving their clinical performance.

Stent pretreatment for internal carotid artery exposed to necrotic lesions in nasopharyngeal carcinoma

BACKGROUND

Post radiation nasopharyngeal necrosis (PRNN) invading the internal carotid artery (ICA) contributes to the death of 69.2-72.7% of PRNN patients. ICA occlusion is an effective treatment to avoid fatal bleeding, while some patients are intolerant. We present a novel method that allows for these patients without interrupting blood flow through the ICA.

METHODOLOGY

This study enrolled patients with PRNN-invaded ICA who were not suitable for ICA occlusion from April 2020 to November 2022. ICA stent pretreatment was performed in the 36 patients and followed the endoscopic nasopharyngectomy (ENPG) or conservative treatment for PRNN. We report the survival outcome and incidence of complications after stent implantation and compare the survival outcomes of ENPG and conservative treatment for PRNN followed by stent implantation.

RESULTS

ICA stent pretreatment was performed in the 36 enrolled patients, among which 14 underwent ENPG, and 22 received conservative treatment. 27.8% patients died after a median follow-up of 15 months. The Kaplan-Meier estimates of overall survival were higher in the ENPG group than in the conservative treatment group. Karnofsky performance status (KPS) was significantly higher in the ENPG group than in the non-ENPG group.

CONCLUSIONS

The innovative application of ICA stents is a promising treatment to improve outcomes in patients with PRNN invading the ICA who are unsuitable for ICA embolization, especially when followed by endoscopic surgery. However, methods to avoid postoperative cerebral ischemia and nasopharyngeal hemorrhage still require further study.

[Research advances of adipose stem cell matrix gel in promoting wound healing]

In recent years, with the problem of aging population in China being prominant, the number of patients with chronic wounds such as diabetic foot, pressure ulcer, and vascular ulcer is increasing. Those diseases seriously affect the life quality of patients and increase the economy and care burden of the patients' family, which have been one of the most urgent clinical problems. Many researches have confirmed that adipose stem cells can effectively promote wound healing, while exogenous protease is needed, and there are ethical and many other problems, which limit the clinical application of adipose stem cells. Adipose stem cell matrix gel is a gel-like mixture of biologically active extracellular matrix and stromal vascular fragment obtained from adipose tissue by the principle of fluid whirlpool and flocculation precipitation. It contains rich adipose stem cells, hematopoietic stem cells, endothelial progenitor cells, and macrophages, etc. The preparation method of adipose stem cell matrix gel is simple and the preparation time is short, which is convenient for clinical application. Many studies at home and abroad showed that adipose stem cell matrix gel can effectively promote wound healing by regulating inflammatory reaction, promoting microvascular reconstruction and collagen synthesis. Therefore, this paper summarized the preparation of adipose stem cell matrix gel, the mechanism and problems of the matrix gel in promoting wound repair, in order to provide new methods and ideas for the treatment of chronic refractory wounds in clinic.

Rare, convergent antibodies targeting the stem helix broadly neutralize diverse betacoronaviruses

Humanity has faced three recent outbreaks of novel betacoronaviruses, emphasizing the need to develop approaches that broadly target coronaviruses. Here, we identify 55 monoclonal antibodies from COVID-19 convalescent donors that bind diverse betacoronavirus spike proteins. Most antibodies targeted an S2 epitope that included the K814 residue and were non-neutralizing. However, 11 antibodies targeting the stem helix neutralized betacoronaviruses from different lineages. Eight antibodies in this group, including the six broadest and most potent neutralizers, were encoded by IGHV1-46 and IGKV3-20. Crystal structures of three antibodies of this class at 1.5-1.75-Å resolution revealed a conserved mode of binding. COV89-22 neutralized SARS-CoV-2 variants of concern including Omicron BA.4/5 and limited disease in Syrian hamsters. Collectively, these findings identify a class of IGHV1-46/IGKV3-20 antibodies that broadly neutralize betacoronaviruses by targeting the stem helix but indicate these antibodies constitute a small fraction of the broadly reactive antibody response to betacoronaviruses after SARS-CoV-2 infection.

Adherence to the Dietary Approaches to Stop Hypertension (DASH) Eating Pattern Reduces the Risk of Head and Neck Cancer in American Adults Aged 55 Years and Above: A Prospective Cohort Study

OBJECTIVES

Dietary Approaches to Stop Hypertension (DASH) pattern has been found to aid in the reduction of obesity, oxidative stress, and chronic inflammation, which are all strongly linked to the development of head and neck cancer (HNC). Nevertheless, no epidemiological studies have investigated the association between this dietary pattern and HNC risk. This study was conducted with the purpose of bridging this gap in knowledge.

DESIGN

A prospective cohort study involving 98,459 American adults aged 55 years and older.

SETTING AND PARTICIPANTS

Data were drawn from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Trial. In the present study, participants with dependable energy intake data who furnished baseline and dietary history information were identified as the study population.

METHODS

Diet was assessed by food frequency questionnaires and the DASH score was calculated to assess each participant's adherence to DASH eating pattern. Cox proportional hazards models were used to calculate multivariable adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the occurrence of HNC. To visualize the variation in cancer risk for HNC and its subtypes across the entire spectrum of DASH scores, restricted cubic spline plots were utilized. Additionally, a series of predefined subgroup analyses were performed to identify potential effect modifiers, and several sensitivity analyses were conducted to assess the stability of the findings.

RESULTS

During a follow-up period of 871,879.6 person-years, 268 cases of HNC were identified, comprising 161 cases pertaining to oral cavity and pharynx cancers, as well as 96 cases of larynx cancer. In the fully adjusted model, adherence to the DASH diet was associated with a remarkable 57% reduction in the risk of HNC when comparing extreme quartiles (HR quartile 4 vs 1: 0.43; 95% CI: 0.28, 0.66; P for trend < 0.001). The restricted cubic spline plots demonstrated a linear dose-response relationship between the DASH score and the risk of HNC as well as its subtypes. Subgroup analysis revealed that the protective effect of the DASH diet against HNC was particularly pronounced in individuals with lower daily energy intake. The primary association remained robust in the sensitivity analysis.

CONCLUSIONS

In American middle-aged and older population, adherence to the DASH diet may help prevent HNC, particularly for individuals with lower daily energy intake.

LBSUN215 Evaluation Of Glycemic Control By Continuous Glucose Monitoring Among Hospitalized Older Adults With Type-2 Diabetes And Frailty

 

Recent observational and meta-analyses have reported a frailty prevalence between 10% and 25% in people with diabetes, in particular in those older than 60 years of age. The impact of frailty on hospital glycemic control and glycemic variability (GV) by continuous glucose monitoring (CGM) in insulin-treated older adults with type 2 diabetes (T2D) is not known. Accordingly, we reviewed data from 3 inpatient randomized clinical trials using CGM in insulin-treated patients with T2D. The validated laboratory-based frailty index (FI-LAB) scale was used for frailty assessment, and participants were categorized into three groups [non-frail: (0-<0.1), pre-frail (≥0.1-<0.21), and frail (≥0.21)] in 84 older adults. | There were no differences on admission clinical characteristics between the non-frail/pre-frail older adults and the frail older adults except for Creatinine (BMI: 32.4 ± 9 vs. 36.83± 13, p=0.21; HbA1c%: 9.3 ± 2 vs. 8.72± 2, p=0.18; Admission BG: 227 ± 114 vs. 194. 07± 75 mg/dl, p=0.26; Cr: 1.16 ± 1 vs. 1.65± 1. 0). There were no differences in GV by coefficient of variation (CV), amplitude of glucose excursion (MAGE), and standard deviation (SD) between the two groups. The correlation between FI-LAB score and percent time with CGM <70 was 0.204 (p=0. 064) and the correlation between FI-LAB score and percent time with percent time with CGM<54 was 0.217 (p=0. 049). Results from standard linear regression and zero-inflated Beta regression further suggest that frail old patients with higher frailty scores may be associated with larger percent time with CGM below range <70 and CGM <54 mg/dL.

Conclusion

Our results indicate that older adults with T2D with higher frailty score experience more time in hypoglycemia during their hospital stay despite having comparable mean daily blood glucose, time in range and glycemic variability compared to non-frail or pre-frail older adults. A larger prospective study is needed to confirm these findings and determine the impact of frailty on clinical outcome. Providers should be vigilant when using insulin or insulin secretagogues in hospitalized older adults with diabetes and frailty.

Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Engineering SARS-CoV-2 neutralizing antibodies for increased potency and reduced viral escape pathways

The rapid spread of SARS-CoV-2 variants poses a constant threat of escape from monoclonal antibody and vaccine countermeasures. Mutations in the ACE2 receptor binding site on the surface S protein have been shown to disrupt antibody binding and prevent viral neutralization. Here, we used a directed evolution-based approach to engineer three neutralizing antibodies for enhanced binding to S protein. The engineered antibodies showed increased in vitro functional activity in terms of neutralization potency and/or breadth of neutralization against viral variants. Deep mutational scanning revealed that higher binding affinity reduces the total number of viral escape mutations. Studies in the Syrian hamster model showed two examples where the affinity-matured antibody provided superior protection compared to the parental antibody. These data suggest that monoclonal antibodies for antiviral indications would benefit from affinity maturation to reduce viral escape pathways and appropriate affinity maturation in vaccine immunization could help resist viral variation.

Broadly neutralizing antibodies target the coronavirus fusion peptide

The potential for future coronavirus outbreaks highlights the need to broadly target this group of pathogens. We used an epitope-agnostic approach to identify six monoclonal antibodies that bind to spike proteins from all seven human-infecting coronaviruses. All six antibodies target the conserved fusion peptide region adjacent to the S2' cleavage site. COV44-62 and COV44-79 broadly neutralize alpha- and betacoronaviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariants BA.2 and BA.4/5, albeit with lower potency than receptor binding domain-specific antibodies. In crystal structures of COV44-62 and COV44-79 antigen-binding fragments with the SARS-CoV-2 fusion peptide, the fusion peptide epitope adopts a helical structure and includes the arginine residue at the S2' cleavage site. COV44-79 limited disease caused by SARS-CoV-2 in a Syrian hamster model. These findings highlight the fusion peptide as a candidate epitope for next-generation coronavirus vaccine development.

Broadly neutralizing antibodies to SARS-related viruses can be readily induced in rhesus macaques

To prepare for future coronavirus (CoV) pandemics, it is desirable to generate vaccines capable of eliciting broadly neutralizing antibody responses to CoVs. Here, we show that immunization of macaques with SARS-CoV-2 spike (S) protein with a two-shot protocol generated potent serum receptor binding domain cross-neutralizing antibody responses to both SARS-CoV-2 and SARS-CoV-1. Furthermore, responses were equally effective against most SARS-CoV-2 variants of concern (VOCs) and some were highly effective against Omicron. This result contrasts with human infection or many two-shot vaccination protocols where responses were typically more SARS-CoV-2 specific and where VOCs were less well neutralized. Structural studies showed that cloned macaque neutralizing antibodies, particularly using a given heavy chain germline gene, recognized a relatively conserved region proximal to the angiotensin converting enzyme 2 receptor binding site (RBS), whereas many frequently elicited human neutralizing antibodies targeted more variable epitopes overlapping the RBS. B cell repertoire differences between humans and macaques appeared to influence the vaccine response. The macaque neutralizing antibodies identified a pan-SARS-related virus epitope region less well targeted by human antibodies that could be exploited in rational vaccine design.

Utilisation of village clinics in Southwest China: evidence from Yunnan Province

INTRODUCTION

Primary healthcare in rural China is underutilised, especially in village clinics in Southwest China. The aim of this study was to explore any relationships among the ethnicity of the healthcare provider, the clinical competence of the healthcare provider, and the utilisation of village clinics in Southwest China.

METHODS

This cross-sectional survey study involved 330 village healthcare providers from three prefectures in Yunnan Province in 2017. Multiple logistic regressions were adopted to investigate the utilisation of primary healthcare among different ethnic healthcare providers.

RESULTS

Primary healthcare utilisation was higher in village clinics where healthcare providers were Han Chinese than those where healthcare providers were ethnic minority (151 vs 101, P=0.008). The logistic regression analysis showed that clinical competence was positively associated with the utilisation of primary healthcare (odds ratio [OR]=1.49, 95% confidence interval [CI]=1.12-2.00; P=0.007) and that inadequate clinical competence of ethnic minority health workers may lead to a lag in the utilisation of primary healthcare (OR=0.45, 95% CI=0.23-0.89; P=0.022).

CONCLUSION

Our results confirm differences in the utilisation of primary healthcare in rural Yunnan Province among healthcare providers of different ethnicities. Appropriate enhancements of clinical competence could be conducive to improving the utilisation of primary healthcare, especially among ethnic minority healthcare providers.

AB0784 Symptoms compatible with Rome IV functional bowel disorder in patients with ankylosing spondylitis

Background

Clinical manifestations of gut problems except for inflammatory bowel disease (IBD) have not been well-established in patients with ankylosing spondylitis (AS). One study investigated that 30% patients with axial spondyloarthritis (axSpA) had irritable bowel syndrome (IBS) symptoms meeting Rome III criteria.[1]

Objectives

To determine the frequency of symptoms meeting Rome IV functional bowel disorder (FBD) in patients with AS, investigate factors associated with FBD symptoms, and assess whether having FBD symptoms might influence AS disease activity.

Methods

In this cross-sectional study, we consecutively enrolled 153 AS patients without known colonic ulcer and 56 sex- and age-matched controls to evaluate FBD (or its subtypes) symptoms.[2] In AS group, logistic regression models were used to explore whether demographic data, disease activity, level of gut inflammation, drug use, and fibromyalgia [3] were associated with presence of gut symptoms. Finally, potential impacts of gut symptoms on AS disease status were assessed in linear regression models.

Results

Sixty (39.2%) of 153 AS patients had FBD symptoms, which was more prevalent than controls (23.2%). Besides, symptoms compatible with IBS and chronic diarrhea were detected in 18 and 43 AS patients respectively. For AS group, multivariable logistic regression analyses showed that symptoms of FBD, IBS, and chronic diarrhea were negatively associated with using non-steroidal anti-inflammatory drug (NSAID), and positively associated with comorbid fibromyalgia, respectively. In exploration about effects of FBD (or its subtypes) symptoms on AS disease activity by multivariable linear regression analyses, FBD symptoms and chronic diarrhea had positive associations with assessments of AS respectively.

Conclusion

Patients with AS had frequent symptoms compatible with FBD, IBS, and chronic diarrhea, proportions of which were lower in those with NSAID-use. The improvement of FBD symptoms, especially chronic diarrhea, might be conducive to disease status of AS patients.

References

[1]Wallman JK, et al. Ann Rheum Dis. 2020;79:159-61.

[2]Mearin F, et al. Gastroenterology. 2016;18:S0016-5085(16)00222-5.

[3]Wolfe F, et al. J Rheumatol. 2011;38:1113-22.

Figure 1.

Frequencies with symptoms meeting FBD criteria

Table 1.

Univariable and multivariable associations between gut symptoms and assessments of AS

Gut symptomsUnivariableMultivariableβpβpASDAS-CRPaFBD symptoms0.2340.1120.294< 0.001IBS symptoms0.0390.863Chronic diarrhea0.2170.1720.3010.002BASDAIbFBD symptoms0.747< 0.0010.764< 0.001IBS symptoms0.2020.560Chronic diarrhea0.7610.0020.845< 0.001BAS-GcFBD symptoms0.936< 0.0010.979< 0.001IBS symptoms0.0590.889Chronic diarrhea0.9030.0030.9490.001ASAS HIdFBD symptoms1.941< 0.0011.6730.003IBS symptoms2.2630.0081.7690.046Chronic diarrhea1.5000.0151.3430.030BASFIeFBD symptoms0.4330.0490.4280.048IBS symptoms0.2960.376Chronic diarrhea0.4480.0600.4250.069BASMIfFBD symptoms-0.3730.190-0.4930.075IBS symptoms-0.4420.304Chronic diarrhea-0.1790.564　　

Besides gut symptoms, other clinical variables (Block-1) being chosen into hierarchical multivariable models were as follows: aHLA-B27, lnCRP, and lnESR; bHLA-B27 and lnESR; cHLA-B27 and lnCRP; dsex and TNFi; eHLA-B27, lnESR, and TNFi; fage and lnESR. Missing data ranging from 1-7%.

Disclosure of Interests

None declared

Cleavage of DNA and RNA by PLD3 and PLD4 limits autoinflammatory triggering by multiple sensors, including endolysosomal TLRs and a STING dependent sensing pathway

We have studied the biochemistry and genetics of Phospholipase D3 (PLD3) and PLD4 because polymorphisms of these proteins have been associated with several important inflammatory and autoimmune diseases, including rheumatoid arthritis, systemic sclerosis, systemic lupus erythematosus and Alzheimer’s disease. We found that both PLD3 and PLD4 are 5’ exonucleases able to degrade both ssDNA and ssRNA. Deficiency in PLD3, PLD4 or both results in a variety of inflammatory defects, with the most serious being lethal hemophagocytic lymphohistiocytosis (HLH) in double knockout mice. Pld3−/−Pld4−/− mice represent a unique spontaneous model of HLH apparently independent of microbes, whereas Pld4−/− mice develop a range of phenotypes depending upon genetic background ranging from macrophage activation syndrome to lupus like disease. Evidence will be presented showing that the diseases in these mice result from autorecognition of nucleic acids and can be reversed by mutation of nucleic acid sensing pathways. PLD3 and PLD4 tend to limit TLR9 recognition but have a more complex effect on recognition by TLR7 and TLR8. Unc93b13d/3dPld3−/−Pld4−/− mice spontaneously signal through STING suggesting that PLD3 and PLD4 also may regulate cytoplasmic nucleic acid sensing.

Supported by NIH grants R01 AI142945 and R56AG070775

Broadly neutralizing antibodies target the coronavirus fusion peptide

The potential for future coronavirus outbreaks highlights the need to develop strategies and tools to broadly target this group of pathogens. Here, using an epitope-agnostic approach, we identified six monoclonal antibodies that bound to spike proteins from all seven human-infecting coronaviruses. Epitope mapping revealed that all six antibodies target the conserved fusion peptide region adjacent to the S2' cleavage site. Two antibodies, COV44-62 and COV44-79, broadly neutralize a range of alpha and beta coronaviruses, including SARS-CoV-2 Omicron subvariants BA.1 and BA.2, albeit with lower potency than RBD-specific antibodies. In crystal structures of Fabs COV44-62 and COV44-79 with the SARS-CoV-2 fusion peptide, the fusion peptide epitope adopts a helical structure and includes the arginine at the S2' cleavage site. Importantly, COV44-79 limited disease caused by SARS-CoV-2 in a Syrian hamster model. These findings identify the fusion peptide as the target of the broadest neutralizing antibodies in an epitope-agnostic screen, highlighting this site as a candidate for next-generation coronavirus vaccine development.

One-Sentence Summary

Rare monoclonal antibodies from COVID-19 convalescent individuals broadly neutralize coronaviruses by targeting the fusion peptide.

miR-34a-5p plays an inhibitory role in hepatocellular carcinoma by regulating target gene VEGFA

OBJECTIVE

The objective of this research is to determine the role of miR-34a-5p in the occurrence and development of HCC by targeting VEGFA.

METHODS

The expression of miR-34a-5p in HCC cell lines and tumour tissue was detected by qRT-PCR; the effect of miR-34a-5p on the invasive ability of HCC cells (SMMC7721 and MHCC97H) were detected by Transwell invasion assay; VEGFA is predicted as a potential target gene of miR-34a-5p by TargetScan, and validated with dual-luciferase reporter gene assay, qRT-PCR and western blot. VEGFA expression in HCC cell lines and tumour tissue was detected using qRT-PCR; the regulation and influence of miR-34a-5p and VEGFA on the proliferation, invasion, migration and the S-phase cell of HCC cells with different invasive abilities were detected by CCK8, Transwell assay, wound healing assay, and flow cytometry. The effect of miR-34a-5p on the growth of tumour was detected by constructing a xenograft model of nude mice with HCC.

RESULTS

It was found that the expression of miR-34a-5p in HCC cells and tumour tissue was significantly decreased. Up-regulating miR-34a-5p expression could reduce the invasion ability of HCC cells. MiR-34a-5p could inhibit the mRNA and protein expression level of VEGFA via combining with the 3'-UTR of VEGFA. VEGFA was highly expressed in HCC cells and tumour tissues. The miR-34a-5p inhibited the proliferation, invasion, migration and S-phase arrest of HCC cells, but this inhibition effect could be neutralised by VEGFA; miR-34a-5p exerted the inhibitory effect on HCC cell proliferation and tumour growth in the HCC xenograft model of nude mice.

CONCLUSION

These results suggest that miR-34a-5p could inhibit the occurrence and development of HCC by targeting VEGFA.

A human antibody reveals a conserved site on beta-coronavirus spike proteins and confers protection against SARS-CoV-2 infection

Broadly neutralizing antibodies (bnAbs) to coronaviruses (CoVs) are valuable in their own right as prophylactic and therapeutic reagents to treat diverse CoVs and as templates for rational pan-CoV vaccine design. We recently described a bnAb, CC40.8, from a CoV disease 2019 (COVID-19) convalescent donor that exhibits broad reactivity with human β-CoVs. Here, we showed that CC40.8 targets the conserved S2 stem helix region of the CoV spike fusion machinery. We determined a crystal structure of CC40.8 Fab with a SARS-CoV-2 S2 stem peptide at 1.6-Å resolution and found that the peptide adopted a mainly helical structure. Conserved residues in β-CoVs interacted with CC40.8 antibody, thereby providing a molecular basis for its broad reactivity. CC40.8 exhibited in vivo protective efficacy against SARS-CoV-2 challenge in two animal models. In both models, CC40.8-treated animals exhibited less weight loss and reduced lung viral titers compared to controls. Furthermore, we noted that CC40.8-like bnAbs are relatively rare in human COVID-19 infection, and therefore, their elicitation may require rational structure-based vaccine design strategies. Overall, our study describes a target on β-CoV spike proteins for protective antibodies that may facilitate the development of pan-β-CoV vaccines.

[Research advances in the treatment of liver failure with mesenchymal stem cell-derived exosomes]

Liver failure is a serious clinical syndrome in which multiple pathogenic factors exceed the liver's self-repair capability, resulting massive hepatocellular necrosis, rapid disease progression and high mortality. Liver transplantation is the most effective method for the treatment of liver failure, but it has disadvantages, such as insufficient liver donor and high cost. The clinical efficacy of mesenchymal stem cells in liver failure have been validated, but its application has been limited to certain extent. Cell-free-based therapies, especially mesenchymal stem cell-derived exosomes, has become a research hotspot in recent years. This paper reviews the research advances in the treatment of liver failure with the use of mesenchymal stem cell-derived exosomes.

A broad and potent neutralization epitope in SARS-related coronaviruses

Many neutralizing antibodies (nAbs) elicited to ancestral SARS-CoV-2 through natural infection and vaccination generally have reduced effectiveness to SARS-CoV-2 variants. Here we show therapeutic antibody ADG20 is able to neutralize all SARS-CoV-2 variants of concern (VOCs) including Omicron (B.1.1.529) as well as other SARS-related coronaviruses. We delineate the structural basis of this relatively escape-resistant epitope that extends from one end of the receptor binding site (RBS) into the highly conserved CR3022 site. ADG20 can then benefit from high potency through direct competition with ACE2 in the more variable RBS and interaction with the more highly conserved CR3022 site. Importantly, antibodies that are able to target this site generally neutralize all VOCs, albeit with reduced potency against Omicron. Thus, this highly conserved and vulnerable site can be exploited for design of universal vaccines and therapeutic antibodies.

Broadly neutralizing anti-S2 antibodies protect against all three human betacoronaviruses that cause severe disease

Pan-betacoronavirus neutralizing antibodies may hold the key to developing broadly protective vaccines against coronaviruses that cause severe disease, for anticipating novel pandemic-causing viruses, and to respond more effectively to SARS-CoV-2 variants. The emergence of the Omicron variant of SARS-CoV-2 has illustrated the limitations of solely targeting the receptor binding domain (RBD) of the envelope Spike (S)-protein. Here, we isolated a large panel of broadly neutralizing antibodies (bnAbs) from SARS-CoV-2 recovered-vaccinated donors that target a conserved S2 region in the fusion machinery on betacoronavirus spikes. Select bnAbs show broad in vivo protection against all three pathogenic betacoronaviruses, SARS-CoV-1, SARS-CoV-2 and MERS-CoV, that have spilled over into humans in the past 20 years to cause severe disease. The bnAbs provide new opportunities for antibody-based interventions and key insights for developing pan-betacoronavirus vaccines.

A human antibody reveals a conserved site on beta-coronavirus spike proteins and confers protection against SARS-CoV-2 infection

Broadly neutralizing antibodies (bnAbs) to coronaviruses (CoVs) are valuable in their own right as prophylactic and therapeutic reagents to treat diverse CoVs and, importantly, as templates for rational pan-CoV vaccine design. We recently described a bnAb, CC40.8, from a coronavirus disease 2019 (COVID-19)-convalescent donor that exhibits broad reactivity with human beta-coronaviruses (β-CoVs). Here, we showed that CC40.8 targets the conserved S2 stem-helix region of the coronavirus spike fusion machinery. We determined a crystal structure of CC40.8 Fab with a SARS-CoV-2 S2 stem-peptide at 1.6 Å resolution and found that the peptide adopted a mainly helical structure. Conserved residues in β-CoVs interacted with CC40.8 antibody, thereby providing a molecular basis for its broad reactivity. CC40.8 exhibited in vivo protective efficacy against SARS-CoV-2 challenge in two animal models. In both models, CC40.8-treated animals exhibited less weight loss and reduced lung viral titers compared to controls. Furthermore, we noted CC40.8-like bnAbs are relatively rare in human COVID-19 infection and therefore their elicitation may require rational structure-based vaccine design strategies. Overall, our study describes a target on β-CoV spike proteins for protective antibodies that may facilitate the development of pan-β-CoV vaccines.

SUMMARY

A human mAb isolated from a COVID-19 donor defines a protective cross-neutralizing epitope for pan-β-CoV vaccine design strategies.

The value of soluble suppression of tumorigenesis-2 (sST2) in the maintenance of hemodialysis patients with heart failure

BACKGROUND

Patients with end-stage renal disease are prone to develop heart failure (HF). The N-terminal pro-brain natriuretic peptide (NT-proBNP, BNP) is regarded as the gold standard for diagnosing HF. However, its prognostic sensitivity in patients with end-stage renal disease is sub-optimal. Soluble suppression of tumorigenesis-2 (sST2) has been well studied in HF but rarely in patients with maintenance hemodialysis (MHD). This study aimed to evaluate the value of sST2 in predicting HF in MHD patients.

METHODS

Twenty-three patients with New York Heart Association (NYHA) class III-IV were included in the HF group and 88 NYHA class I-II patients in the non-heart failure (NHF) group. sST2 and laboratory indexes were compared between the two groups.

RESULTS

The HF group, compared with the NHF group, presented with higher sST2, more advanced age, higher incidence of coronary heart disease (CHD), left ventricle end-diastolic diameter (LVEDD), and pulmonary artery pressure (PAP), and unchanged parathyroid hormone (iPTH). The HF group also had lower ejection fraction (EF), uric acid, inorganic phosphorus, 25-OH VitD3, and serum albumin. Multivariate logistic regression indicated that age, BNP, and sST2 were independent risk factors of HF in MHD patients. Spearman analysis defined that sST2 was positively correlated with PAP (r =0.283, p =0.003) and C-reactive protein (r =0.354, p <0.001); and negatively correlated with sex (r =-0.255, p =0.007), albumin (r =-0.366, p <0.001), uric acid (r =-0.213, p =0.025), 25-OH VitD3 (r =-0.216, p =0.04), calcium (r =-0.219, p =0.021), and inorganic phosphorus (r =-0.256, p =0.007). Receiver operating characteristic curve analysis determined a positive association between BNP and sST2 (r =0.373, p <0.001), with the area under the curve (AUC) of BNP being 0.822 (sensitivity: 0.783, specificity: 0.830) and the AUC of sST2 being 0.841 (sensitivity: 0.913, specificity: 0.761). The AUC of sST2 was 0.841, and the cut-value was 42.840 (sensitivity: 0.913, specificity: 0.761).

CONCLUSION

sST2 can predict HF in MHD patients and facilitate early diagnosis and prevention of HF in MHD patients. HIPPOKRATIA 2022, 26 (1):19-24.

Bispecific antibodies targeting distinct regions of the spike protein potently neutralize SARS-CoV-2 variants of concern

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern threatens the efficacy of existing vaccines and therapeutic antibodies and underscores the need for additional antibody-based tools that potently neutralize variants by targeting multiple sites of the spike protein. We isolated 216 monoclonal antibodies targeting SARS-CoV-2 from plasmablasts and memory B cells collected from patients with coronavirus disease 2019. The three most potent antibodies targeted distinct regions of the receptor binding domain (RBD), and all three neutralized the SARS-CoV-2 Alpha and Beta variants. The crystal structure of the most potent antibody, CV503, revealed that it binds to the ridge region of SARS-CoV-2 RBD, competes with the angiotensin-converting enzyme 2 receptor, and has limited contact with key variant residues K417, E484, and N501. We designed bispecific antibodies by combining nonoverlapping specificities and identified five bispecific antibodies that inhibit SARS-CoV-2 infection at concentrations of less than 1 ng/ml. Through a distinct mode of action, three bispecific antibodies cross-linked adjacent spike proteins using dual N-terminal domain–RBD specificities. One bispecific antibody was greater than 100-fold more potent than a cocktail of its parent monoclonals in vitro and prevented clinical disease in a hamster model at a dose of 2.5 mg/kg. Two bispecific antibodies in our panel comparably neutralized the Alpha, Beta, Gamma, and Delta variants and wild-type virus. Furthermore, a bispecific antibody that neutralized the Beta variant protected hamsters against SARS-CoV-2 expressing the E484K mutation. Thus, bispecific antibodies represent a promising next-generation countermeasure against SARS-CoV-2 variants of concern.

One-shot identification of SARS-CoV-2 S RBD escape mutants using yeast screening

The potential emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) escape mutants is a threat to the efficacy of existing vaccines and neutralizing antibody (nAb) therapies. An understanding of the antibody/S escape mutation landscape is urgently needed to preemptively address this threat. Here we describe a rapid method to identify escape mutants for nAbs targeting the S receptor binding site. We identified escape mutants for five nAbs, including three from the public germline class VH3-53 elicited by natural coronavirus disease 2019 (COVID-19) infection. Escape mutations predominantly mapped to the periphery of the angiotensin-converting enzyme 2 (ACE2) recognition site on the RBD with K417, D420, Y421, F486, and Q493 as notable hotspots. We provide libraries, methods, and software as an openly available community resource to accelerate new therapeutic strategies against SARS-CoV-2.

Structural and functional ramifications of antigenic drift in recent SARS-CoV-2 variants

Neutralizing antibodies (nAbs) elicited against the receptor binding site (RBS) of the spike protein of wild-type severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are generally less effective against recent variants of concern. RBS residues Glu484, Lys417, and Asn501 are mutated in variants first described in South Africa (B.1.351) and Brazil (P.1). We analyzed their effects on angiotensin-converting enzyme 2 binding, as well as the effects of two of these mutations (K417N and E484K) on nAbs isolated from COVID-19 patients. Binding and neutralization of the two most frequently elicited antibody families (IGHV3-53/3-66 and IGHV1-2), which can both bind the RBS in alternative binding modes, are abrogated by K417N, E484K, or both. These effects can be structurally explained by their extensive interactions with RBS nAbs. However, nAbs to the more conserved, cross-neutralizing CR3022 and S309 sites were largely unaffected. The results have implications for next-generation vaccines and antibody therapies.

[Advances in the study of mesenchymal stem cells for end-stage liver disease]

End-stage liver disease refers to the advanced stage of liver disease caused by various chronic liver damage. Orthotopic liver transplantation is the most important final treatment option, but liver transplantation is still limited by many factors at present. Stem cell transplantation therapy has attracted widespread attention as a potential treatment for end-stage liver disease. This article reviews the research progress of mesenchymal stem cell therapy in end-stage liver disease.