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The Eagle Bioscience’s Coronavirus COVID-19 IgG ELISA Assay was recently highlighted in a publication on the decline of Sars-CoV-2 antibodies over 6-month follow-up in obstetrical healthcare workers (HCW). Researchers investigated the longitudinal presence of serum Sars-CoV-2 specific antibodies for both Immunoglobulin G (IgG) and Immunoglobulin M (IgM) in obstetrical HCWs at a tertiary hospital. Check out the full article below.

Abstract

The Problem

Limited data exists on the temporal trend of the Sars-CoV-2 immunologic response and duration of protection following natural infection. We sought to investigate the presence and duration of Sars-CoV-2 serum antibodies in obstetrical healthcare workers (HCW) on serial assessments over a 6-month period, and to assess rates of vaccine acceptance and reported vaccine side effects among this cohort.

Method of Study

A prospective cohort study of a convenience sample of obstetrical HCWs at a tertiary hospital. Serum Sars-CoV-2 antibodies for Immunoglobulin G (IgG) and Immunoglobulin M (IgM) were measured longitudinally at four intervals: baseline, 4 weeks, 12 weeks, and 6 months. Participants completed voluntary surveys on COVID19 testing, high-risk exposures, vaccine acceptance, and vaccine side effects.

Results

One hundred twenty-six of 150 (84%) HCWs who volunteered for participation completed all four blood draws. Prevalence of seropositive HCWs based on positive Sars-CoV-2 IgG antibodies increased from 2% at baseline to 31% at 12 weeks but declined to 21% by 6 months. Forty-two percent (19/43) of the participants considered seropositive for Sars-CoV-2 IgG antibodies at any of the initial three blood draws converted to seronegative status at the 6-month follow-up. Eighty-seven percent (72/83) of participants who responded to a follow-up survey were willing to accept the COVID19 vaccine. Rates of acceptance did not differ by participant antibody status. Those that experienced symptoms with the first injection were more likely to have positive Sars-CoV-2 IgG antibodies (36.8% vs. 9.6%, p = .01).

Conclusion

Sars-CoV-2 IgG antibodies wane over time and may not provide prolonged and robust immune protection. This underscores the importance of vaccination and continued research in this area while the COVID19 pandemic continues.

Kiefer M.K., Allen K.D., Russo J.R., et al. Decline in Sars-CoV-2 antibodies over 6-month follow-up in obstetrical healthcare workers. Am. J. Reprod. Immunol. (2021)

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The Eagle Bioscience’s MedFrontier Intact FGF23 Assay was utilized in a recent publication to determine intestinal phosphorus absorption in patients with moderate chronic kidney disease (CDK) and healthy adults. Find the abstract and full text below.

Abstract

Reducing intestinal phosphorus absorption is a cornerstone in CKD-MBD management. Yet, knowledge gaps include how CKD pathophysiology affects intestinal phosphorus absorption. In vivo rodent studies suggest that intestinal phosphorus absorption remains inappropriately normal in early-moderate CKD, despite declining 1,25-dihydroxyvitamin D (1,25D). We measured intestinal phosphorus absorption in patients with moderate CKD versus healthy adults using a direct radiotracer method. Patients with CKD and healthy adults matched for age, sex, and race were enrolled in this 8-day controlled diet study: the first 6 days outpatient and the final 2 days inpatient. Oral and intravenous doses of 33P and serial blood and urine sampling determined intestinal phosphorus absorption during the final 2 days. Secondary outcomes included fasting biochemistries and 24-hour urine phosphorus (uP). In total, n=8 patients with CKD (eGFR=29-55 ml/min per 1.73 m2) and n=8 matched healthy controls completed the study. On a controlled diet, no difference in fractional intestinal phosphorus absorption was detected between patients with CKD and healthy adults (0.69 versus 0.62, respectively; P=0.52), and this was similar for 24-hour uP (884 versus 935 mg/d, respectively; P=0.70). Fractional intestinal phosphorus absorption was not significantly related to 24-hour uP. Patients with CKD had higher serum intact PTH and intact FGF23 and lower 1,25D. The relationship between 1,25D and fractional intestinal phosphorus absorption was not statistically significant. Intestinal phosphorus absorption with typical dietary intake did not differ in patients with moderate CKD compared with controls, despite lower serum 1,25D levels. In this setting, a relationship between 24-hour uP and fractional or absolute intestinal absorption was not evident. Further investigation is needed to determine what factors influence intestinal phosphorus absorption in CKD and the apparent lack of compensation by the intestine to limit phosphorus absorption in the face of declining kidney function and reduced 1,25D. Whether this is evident across a range of dietary phosphorus intakes, as well as CKD severity, also needs to be determined.

Stremke E.R, Wises G.N., Moe S.M., et al. Intestinal Phosphorus Absorbtion in Moderate CKD and Healthy Adults Determined Using a Radioisotopic Tracer. J. Am. Soc. Nephrol. (2021) 32(8):2057-2069

If you have any questions about the MedFrontier Intact FGF23 Assay or our other offerings, please contact us here.

The Eagle Bioscience’s Dopamine Sensitive ELISA Assay was utilized in a recent publication on how Hexachloronaphthalene (HxCN) impairs the dopamine pathway in an in vitro model of PC12 cells. This is the first study to demonstrate that HxCN administered in vitro inhibits dopamine biosynthesis and secretion through the regulation of tyrosine hydroxylase and VMAT1 expression. Check out the abstract and full article below.

Abstract

Among polychlorinated naphthalenes (PCNs), listed by the Stockholm convention as Persistent Organic Pollutants (POPs), hexachloronaphthalenes are considered the most toxic and raise the highest concern. Of these, 1,2,3,5,6,7-hexachloronaphthalanene (PCN67) is considered the main congener affecting human health due to its hepatotoxicity and its ability to disturb the reproductive, endocrine, and hematological systems. It is also prevalent in human serum/plasma, milk, and adipose tissue. However, little is known about its neurotoxicity, despite the fact that anorectic effects have been observed in workers occupationally exposed to PCNs and in animal research on PCN67. Since dopamine is involved in many aspects of food intake, the aim of this study was to confirm whether PCN67 affects dopamine synthesis in differentiated PC12 cells, a widely used model of neurosecretion. Our results show that exposure to PCN67 resulted in diminished dopamine content and release. Moreover, PCN67 also affected the expression of tyrosine hydroxylase and lowered the expression of vesicular monoamine transporter 1 (VMAT1). In addition, significantly lower expression of antioxidant enzymes, including catalase, glutathione peroxidase and copper/zinc superoxide dismutase, was observed in comparison to the vehicle. In conclusion, PCN67 appears to disturb dopaminergic transmission by altering tyrosine hydroxylation, reducing VMAT1 expression and impairing antioxidant protection. Our study provides a potential mechanism for how PCN67 may cause dopamine deficiency and contribute to neuronal death by affecting cellular antioxidant potency; however, this conclusion requires further research.

Lisek M., Boczek T., Stragierowicz J., et al. Hexachloronaphthalene (HxCN) impairs the dopamine pathway in an in vitro model of PC12 cells. Chemosphere. (2021) 287:3.

If you have any questions about the Dopamine Sensitive ELISA Assay or our other offerings, please contact us here.

The Eagle Bioscience’s Anti-Beta2 Glycoprotein 1 IgG ELISA was recently highlighted in a publication on the effects of hydroxychloroquine onantiphospholipid antibodies-inhibited endometrial angiogenesis. Check out the abstract and full-text article below.

Abstract

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombotic events and/or pregnancy morbidity (≥3 recurrent early miscarriage or fetal death or a prematurity <34 weeks of gestation) with persistently positive antiphospholipid antibodies (aPLs). It is reported that aPLs damage the placental tissue by binding to β2-glycoprotein I (β2GPI) on the surface of trophoblast and endothelial cells. Hydroxychloroquine (HCQ) is considered to be beneficial in the treatment of obstetrical APS and shown to restore the aPL-inhibited invasion and differentiation of trophoblast. However, not enough evidence exists regarding the effect of HCQ on endometrial angiogenesis. The aim of our study was to assess whether HCQ has an effect on aPL-inhibited endothelial angiogenesis. In this research, to explore the effect of HCQ for angiogenesis, we investigated: Human umbilical vein endothelial cells (HUVECs) viability by CCK-8; HUVECs migration by wound healing; HUVEC angiogenesis by Matrigel assay in vitro; mRNA expression of MMP-2 and VEGF by real-time quantitative Polymerase Chain Reaction (RT-PCR); protein expression of VEGF, MMP-2 by western blot. We found that HCQ treatment significantly restored the expression of aPL-inhibited VEGF and MMP-2. HCQ restored aPL-inhibited HUVEC proliferation, migration, and angiogenesis in vitro. In conclusion, aPLs inhibit HUVECs angiogenesis, however, HCQ can restore the effect of aPL-inhibited HUVECs migration and angiogenesis in vitro, demonstrating its beneficial therapeutic role in obstetrical APS.

Dong Y., Lu Y., Xia Y., Wang X. Effect of hydroxychloroquine on antiphospholipid antibodies inhibited endometrial angiogenesis. J. Matern. -Fetal Neonatal Med. (2021).

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The Eagle Bioscience’s 25-OH Vitamin D ELISA Assay was highlighted in a recent publication by the Department of Oncology at Gerogetown Univeristy in DC. Researchers determined how the vitamin D receptor is linked to disease outcome in estrogen receptor-positive (ER+) breast cancer patients treated with tamoxifen (TAM). Check out the abstract and full text article below.

Abstract

We determined how vitamin D receptor (VDR) is linked to disease outcome in estrogen receptor-positive (ER+) breast cancer patients treated with tamoxifen (TAM). Breast cancer patients (n = 581) in four different datasets were divided into those expressing higher (above median) and lower levels of VDR in pretreatment ER+ tumors. Across all datasets, TAM-treated patients with higher pretreatment tumor VDR expression exhibited significantly longer recurrence-free survival. Ingenuity pathway analysis identified autophagy and unfolded protein response (UPR) as top differentially expressed pathways between high and low VDR-expressing ER+ cancers. Activation of VDR with vitamin D (VitD), either calcitriol or its synthetic analog EB1089, sensitized MCF-7-derived, antiestrogen-resistant LCC9 human breast cancer cells to TAM, and attenuated increased UPR and pro-survival autophagy. Silencing of VDR blocked these effects through the IRE1α-JNK pathway. Further, silencing of VDR impaired sensitivity to TAM in antiestrogen-responsive LCC1 cells, and prevented the effects of calcitriol and EB1089 on UPR and autophagy. In a preclinical mouse model, dietary VitD supplementation induced VDR activation and reduced carcinogen-induced ER+ mammary tumor incidence. In addition, IRE1α-JNK signaling was downregulated and survival autophagy was inhibited in mammary tumors of VitD-supplemented mice. Thus, activation of VDR is predictive of reduced risk of breast cancer recurrence in ER+ patients, possibly by inhibiting antiestrogen-promoted pro-survival autophagy.

Li, Y., Cook, KL., Yu, W., et al. Inhibition of Antiestrogen-Promoted Pro-Survival Autophagy and Tamoxifen Resistance in Breast Cancer through Vitamin D Receptor. Nutrients. (2021) 13(5):1715

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The Eagle Bioscience’s Mouse Rat 25-OH Vitamin D ELISA was recently highlighted about how the MicroRNA-122 contributes to lipopolysaccharide-induced acute kidney injury via down-regulating the vitamin D receptor in the kidney.

Abstract

Background
Our previous studies showed that vitamin D receptor (VDR) depletion promotes lipopolysaccharide (LPS)-induced acute kidney injury (AKI) in mice, and renal VDR is down-regulated in AKI, but the mechanism of VDR down-regulation is unclear.

Methods
Nutritional vitamin D deficiency was induced by feeding mice a vitamin D-deficient (VD-D) diet. Mice were injected intraperitoneally with LPS (20 mg/kg) to establish LPS-induced AKI. Levels of VDR and miR-122 were measured both in vivo and in vitro. The associations between VDR and miR-122 were analysed by dual-luciferase reporter assays.

Results
Compared with vitamin D-sufficient (VD-S) mice, VD-D mice developed more severe renal injury following LPS challenge. LPS induced a dramatic decrease in VDR expression and marked induction of miR-122 both in vivo and in vitro. Furthermore, miR-122 hairpin inhibitor alleviated LPS-induced VDR down-regulation whereas miR-122 mimic directly suppressed VDR expression in HK-2 cells. In luciferase reporter assays, miR-122 mimic was able to suppress luciferase activity in 293T cells co-transfected with a luciferase reporter that contains a putative miR-122 target site from 3′UTR of the VDR transcript, but not when this site was mutated. Moreover, miR-122 mimic significantly blocked paricalcitol-induced luciferase activity in 293T cells co-transfected with a VDRE-driven luciferase reporter, whereas miR-122 hairpin inhibitor enhanced paricalcitol’s activity to suppress PUMA and caspase 3 activation induced by LPS in HK-2 cells.

Conclusions
Collectively, these studies provide evidence that miR-122 directly targets VDR in renal tubular cells, which strongly suggest that miR-122 up-regulation in the kidney under LPS challenge contributes to kidney injury by down-regulating VDR expression.

He, J., Du, J., Yi, B., et al. MicroRNA-122 contributes to lipopolysaccharide-induced acute kidney injury via down-regulating the vitamin D receptor in the kidney. European Journal of Clinical Investigation. (2021) Full Text Here.

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