Suzanne Pears

A Cross-Sectional Study of Ageing and Cardiovascular Function over the Baboon Lifespan

Background Ageing is associated with changes at the molecular and cellular level that can alter cardiovascular function and ultimately lead to disease. The baboon is an ideal model for studying ageing due to the similarities in genetic, anatomical, physiological and biochemical characteristics with humans. The aim of this cross-sectional study was to investigate the changes in cardiovascular profile of baboons over the course of their lifespan. Methods Data were collected from 109 healthy baboons (Papio hamadryas) at the Australian National Baboon Colony. A linear regression model, adjusting for sex, was used to analyse the association between age and markers of ageing with P < 0.01 considered significant. Results Male (n = 49, 1.5–28.5 years) and female (n = 60, 1.8–24.6 years) baboons were included in the study. Age was significantly correlated with systolic (R2 = 0.23, P < 0.001) and diastolic blood pressure (R2 = 0.44, P < 0.001), with blood pressure increasing with age. Age was also highly correlated with core augmentation index (R2 = 0.17, P < 0.001) and core pulse pressure (R2 = 0.30, P < 0.001). Creatinine and urea were significantly higher in older animals compared to young animals (P < 0.001 for both). Older animals (>12 years) had significantly shorter telomeres when compared to younger (<3 years) baboons (P = 0.001). Conclusion This study is the first to demonstrate that cardiovascular function alters with age in the baboon. This research identifies similarities within cardiovascular parameters between humans and baboon even though the length of life differs between the two species.

CD83 is a new potential biomarker and therapeutic target for Hodgkin lymphoma

Chemotherapy and hematopoietic stem cell transplantation are effective treatments for most Hodgkin lymphoma patients, however there remains a need for better tumor-specific target therapy in Hodgkin lymphoma patients with refractory or relapsed disease. Herein, we demonstrate that membrane CD83 is a diagnostic and therapeutic target, highly expressed in Hodgkin lymphoma cell lines and Hodgkin and Reed-Sternberg cells in 29/35 (82.9%) Hodgkin lymphoma patient lymph node biopsies. CD83 from Hodgkin lymphoma tumor cells was able to trogocytose to surrounding T cells and, interestingly, the trogocytosing CD83+T cells expressed significantly more programmed death-1 compared to CD83−T cells. Hodgkin lymphoma tumor cells secreted soluble CD83 that inhibited T-cell proliferation, and anti-CD83 antibody partially reversed the inhibitory effect. High levels of soluble CD83 were detected in Hodgkin lymphoma patient sera, which returned to normal in patients who had good clinical responses to chemotherapy confirmed by positron emission tomography scans. We generated a human anti-human CD83 antibody, 3C12C, and its toxin monomethyl auristatin E conjugate, that killed CD83 positive Hodgkin lymphoma cells but not CD83 negative cells. The 3C12C antibody was tested in dose escalation studies in non-human primates. No toxicity was observed, but there was evidence of CD83 positive target cell depletion. These data establish CD83 as a potential biomarker and therapeutic target in Hodgkin lymphoma.

The effect of acetyl salicylic acid (Aspirin) on trophoblast-endothelial interaction in vitro

Early administration of low dose acetyl salicylic acid (Aspirin) in high risk women reduces the risk of early onset preeclampsia. This study aims to investigate the effect of aspirin on trophoblast integration and the its effect on angiogenic and invasive pathways in an in-vitro model of preeclampsia. Red fluorescent-labeled human uterine myometrial microvascular endothelial cells (UtMVECs) were seeded on matrigel to form endothelial networks. Green fluorescent-labeled trophoblastic HTR-8/SVneo cells were co-cultured with the endothelial networks with/without TNF-a (0.5ng/mL) and/or aspirin (0.1mM) for 24h. Fluorescent images were captured and quantified by Image J to examine the effects of TNF-a and aspirin on the trophoblast-endothelial integration. Conditioned media were collected to measure free VEGF, PlGF and sFlt-1 by ELISA and PGF1a by Enzyme immunoassay (EIA). Cells were retrieved to examine mRNA expression of angiogenic factors (VEGF, PlGF and sFlt-1), invasion markers (MMP-2 and TIMP-1), endothelial cell activation markers (E-selectin and VCAM), eNOS and cyclooxygenase (COX)-2 by quantitative PCR. Aspirin reversed the inhibitory effect of TNF-a on trophoblast cell integration into endothelial cellular networks. TNF-a increased PGF1a production (128±11%, p<0.05), whilst aspirin reversed the TNF-a effect on PGF1a production (19±4%, p<0.01). TNF-a decreased the mRNA expression of PlGF, eNOS, MMP-2 and TIMP-1, and stimulated COX2, E-selectin and VCAM mRNA expression. Aspirin did not reverse the TNF-a effect on these molecules. Aspirin improves trophoblast cell integration into endothelial cellular networks by inhibiting the effect of TNF-a via PGI2 with no significant effect on antiangiogenic, invasive or endothelial activation markers.

Characterization of the New Immune Suppressive Anti Human CD83 Monoclonal Antibody 3C12C in Non-Human Primates

Introduction CD83 is a member of the Ig superfamily. It is membrane bound on activated dendritic cells (DC) and B cells. We developed a potential therapeutic human anti-human CD83 monoclonal antibody (3C12C) and showed it prevents graft versus host disease in a human PBMC mouse xenograft model. After establishing that 3C12C binds to non-human primate (NHP, baboon Papio Hamadryas) cells, we tested 3C12C in vivo in NHPs before a first in man, first in class, Phase I clinical trial. Methods Five baboons received 3C12C (1, 5, 10mg/kg, iv) or human IgG 10mg/kg on d0, 7, 14 and d21. Peripheral blood and serum were collected weekly (x4) then every 4 weeks (x2). Bone marrow and lymph node (LN) biopsies were taken at d28. Blood counts and biochemistry were monitored. Flow cytometry analysis followed the PBMC DC subsets, B cells and T cells and bone marrow haematopoietic stem cells. Immune histological studies were performed on LNs. Results All 5 animals remained well following anti-CD83 antibody injection. 3C12C did not change blood counts or liver function. CD4+T, CD8+T and B cells remained normal to d84. 3C12C injection increased peripheral Treg transiently at d21. 3C12C reduced blood CD1c+DC in a dose dependent manner. CD1c+DC were reduced in LN. 3C12C had no influence on bone marrow hematopoietic stem cell numbers. Conclusion Our results demonstrate that 3C12C is safe in NHPs and that it reduced activated DC numbers. This data will facilitate our planned Phase I trial of 3C12C in allogenic hematopoietic stem cell transplantation.

The chronobiology of blood pressure in pregnancy

This review summarizes the literature to date on the subject of the chronobiology of blood pressure in pregnancy, and more specifically, in the common disease state of high blood pressure in pregnancy or preeclampsia. While the guidelines for treating hypertension in pregnancy use absolute measures to start treatment, they do not take into account the important rhythms of hypertension including nighttime and daytime readings. These variations are likely to have strong impacts on pregnancy outcomes, risk and long-term hypertension risk.

Increased salt sensitivity in offspring of pregnancies complicated by experimental preeclampsia

Preeclampsia is a hypertensive disorder of pregnancy known to increase the risk of cardiovascular disease in mothers and offspring. Offspring exposed to a suboptimal intrauterine environment may experience altered fetal programming and subsequent long‐term cardiovascular changes. This study investigated changes in the vascular response in offspring from experimental preeclampsia (EPE) induced by uterine artery ligation, in the absence of fetal growth restriction, compared to normal baboon pregnancies (controls), following a high salt diet challenge. After 1 week of standard diet (containing <1% salt), animals were fed a high salt diet (6%) for 2 weeks. Systolic and diastolic blood pressure (SBP, DBP), aldosterone, renin and creatinine clearance were evaluated in EPE (n = 6, 50% male) and control (n = 6, 50% male) offspring. A repeated measures analysis was performed, and P < 0.05 was considered significant. At baseline, there were no differences between the groups in any parameter (EPE, mean age and weight 3.2 ± 1.2 years, 6.8 ± 1.0 kg, respectively; Control, 2.9 ± 0.8 years, 7.1 ± 1.5 kg). After salt loading the EPE group had significantly higher SBP (92 ± 5 mm Hg) compared to the control group (83 ± 4 mm Hg, P = 0.03). Aldosterone concentration was higher in the EPE group despite the same salt excretion and no difference in renal function. Salt sensitivity may differ in offspring from hypertensive pregnancies due to fetal programming. This could have long‐term consequences for cardiovascular health of EPE offspring and further research is required to determine the exact pathological mechanisms.