Bilirubin Links Heme Metabolism to Neuroprotection by Scavenging Superoxide

Bilirubin is one of the most frequently measured metabolites in medicine, yet its physiologic roles remain unclear. Bilirubin can act as an antioxidant in vitro, but whether its redox activity is physiologically relevant is unclear because many other antioxidants are far more abundant in vivo. Here, we report that depleting endogenous bilirubin renders mice hypersensitive to oxidative stress. We find that mice lacking bilirubin are particularly vulnerable to superoxide (O₂^⋅-) over other tested reactive oxidants and electrophiles. Whereas major antioxidants such as glutathione and cysteine exhibit little to no reactivity toward O₂^⋅-, bilirubin readily scavenges O₂^⋅-. We find that bilirubin's redox activity is particularly important in the brain, where it prevents excitotoxicity and neuronal death by scavenging O₂^⋅- during NMDA neurotransmission. Bilirubin's unique redox activity toward O₂^⋅- may underlie a prominent physiologic role despite being significantly less abundant than other endogenous and exogenous antioxidants.

Abstract P3-13-11: The outcomes of ReFilx soft tissue filler as an immediate reconstruction technique for lumpectomy followed by radiotherapy

Introduction: Lumpectomy for breast cancer can often result in poor cosmetic outcomes which can lead to long-lasting impairment of quality of life. ReFilx is a synthetic porous degradable polyurethane scaffold that has mechanical properties comparable to that of native healthy breast tissue. It has been shown in two previous porcine studies to preserve breast shape and volume over 9 months when inserted into the cavities immediately after lumpectomy. We observed minimal foreign body reaction with good integration of the host tissue while the material degraded over time. In this study, we examined the healing process of lumpectomy treated with radiation. Radiotherapy is currently a standard adjuvant therapy after lumpectomy for breast cancers; and radiation is known to affect the healing process in general. Objective: To evaluate ReFilx, as soft tissue fillers for lumpectomy cavities in combination with standard radiotherapy. Hypothesis: ReFilx will preserve breast shape and volume by supporting tissue infiltration with minimal inflammation in the presence of clinically relevant radiotherapy. Methods: 3 female Yucatan minipigs received lumpectomies carried out using electrocautery to remove normal breast tissue of approximately 2 cm diameter, after which the cavities were filled with (case) or without ReFilx (sham control) (n=3 for each condition, each pig has 12-13 breasts). 6 weeks post-implantation, 2 of the pigs received radiation directed at the right half of their bodies (6 breasts per pig) for a total dose of 42.4 Gy delivered over 15 fractions using a clinical linear accelerator. The delivered doses to target sites and the adjacent tissue were confirmed with optically stimulated luminescent dosimeters (OSLDs). A third pig was maintained as a non-irradiated control. Ultrasound examinations were performed every 3 weeks post-implantation. At week 24 and 36, samples consisted of n=3 for irradiated and non-irradiated ReFilx and sham sites for the half-irradiated pigs, and n=3 for non-irradiated ReFilx and sham sites for the non-irradiated control pig were excised by mastecomy, the tissue samples were fixed in 10% buffered formalin for subsequent histological (H&E, Masson's Trichrome) studies. Potential side effects were monitored by vital signs, pain control, wound checks, ultrasound and blood tests. Necropsies were performed at the conclusion of the study. Results: Ultrasound examination indicated no difference between ReFilx's ability to maintain breast shape and volume with or without the presence of radiation treatment, in contrast to the collapse of the sham sites by 24 weeks. Similarly, the histology of irradiated and non-irradiated ReFilx samples showed similar levels of tissue infiltration, inflammatory changes and degradation of ReFilx. There was no significant side effects observed. Conclusions: ReFilx's ability to act as a soft tissue filler for breast volume restoration post-lumpectomy does not appear to be significantly impacted by the presence of clinically relevant radiation treatment. Longer-term follow-up is currently in progress for this study. Acknowledgements: Connaught Innovation Award (University of Toronto) and Joule Innovation Fund (Canadian Medical Association).

Citation Format: Leong WL, Battiston K, Cheung F, Fulton C, Lin A, Levin W, Done S, Santerre P. The outcomes of ReFilx soft tissue filler as an immediate reconstruction technique for lumpectomy followed by radiotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-13-11.

Abstract P1-20-02: Incidence of hyperglycemia in non-diabetic patients with early-stage breast cancer treated with chemotherapy

Background: There are shared risk factors between breast cancer (BC) and diabetes mellitus (DM). BC treatments including chemotherapy given in combination with glucocorticoids can induce hyperglycemia and steroid related DM. Patients with DM are at increased risk of developing chemotherapy related toxicities such as chemotherapy induced peripheral neuropathy (CIPN) compared to those without DM. The incidence of hyperglycemia during chemotherapy in non-diabetic patients with early-stage breast cancer is unknown.

Methods: We performed a retrospective analysis of non-diabetic women with stage I-III breast cancer treated with chemotherapy at Columbia University Medical Center from 9/1/2016-8/31/2017 to evaluate hyperglycemia incidence during chemotherapy and up to six months after chemotherapy completion. Eligible patients were identified in the electronic health record (EHR) by ICD9 and 10 codes (ICD9 174.x and ICD10 C50.x) and a record of chemotherapy administration. Non-diabetic patients were defined by chart review as no recorded history of diabetes and no receipt of a diabetes medication in the EHR. Breast cancer stage was determined by chart review. Glucose values were recorded prior to chemotherapy, during chemotherapy, and for six-months after chemotherapy completion. We defined hyperglycemia as a glucose value of ≥200 mg/dl. Median time to hyperglycemia was also calculated.

Results: We identified 82 eligible patients. The majority of patients received dexamethasone during their chemotherapy course (79 patients, 96.3%). The most frequent chemotherapy regimen was doxorubicin/cyclophosphamide and paclitaxel (32 patients, 39.0%). At baseline, 20 patients (24.4%) had a normal body mass index (BMI), 27 patients (32.9%) were overweight, and 31 patients (37.8%) were obese. Hyperglycemia occurred in 8 patients (9.8%) after initiation of chemotherapy. Among patients with hyperglycemia, the maximum blood glucose was between 200-299 mg/dl in seven patients (87.5%), and between 500-599 in one patient (12.5%). The median time to hyperglycemia was 84 days. Among patients who did not experience hyperglycemia, the maximum blood glucose was between 140-159 mg/dl in six patients (8.1%), between 160-179 mg/dl in eight patients (10.8%), and between 180-199 mg/dl in three patients (4.1%). Three patients were diagnosed with DM following chemotherapy completion.

Conclusion: Hyperglycemia occurred in almost 10% of non-diabetic patients who received chemotherapy for early-stage breast cancer. Additionally, over 30% of patients had a blood glucose of 140 mg/dl or higher after chemotherapy initiation. The impact of hyperglycemia on the development of chemotherapy related toxicities in this group is unknown. Future research is needed to identify effective interventions for glucose control during chemotherapy, and to determine if glucose control during treatment can reduce the risk of chemotherapy related toxicities, specifically CIPN.

Citation Format: Accordino MK, Lin A, Wright JD, Trivedi MS, Kalinsky K, Crew KD, Hershman DL. Incidence of hyperglycemia in non-diabetic patients with early-stage breast cancer treated with chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-20-02.

The Ultra-High-Risk for psychosis groups: Evidence to maintain the status quo

Individuals are considered Ultra-High-Risk (UHR) for psychosis if they meet a set of standardised criteria including presumed genetic vulnerability (Trait), or a recent history of Attenuated Psychotic Symptoms (APS) or Brief Limited Intermittent Psychotic Symptoms (BLIPS). Recent calls to revise these criteria have arisen from evidence that Trait, APS and BLIPS groups may transition to psychosis at different rates. Concurrently, it has become clear that the UHR status confers clinical risk beyond transition to psychosis. Specifically, most UHR individuals will not develop psychosis, but will experience high rates of non-psychotic disorders, persistent APS and poor long-term functional outcomes. Rather than focus on transition, the present study investigated whether UHR groups differ in their broader clinical risk profile by examining baseline clinical characteristics and long-term outcomes other than transition to psychosis. Four UHR groups were defined: Trait-only, APS-only, Trait+APS, and any BLIPS. Participants (N=702) were recruited upon entry to early intervention services and followed-up over a period of up to 13years (mean=4.53, SD=3.84). The groups evidenced similar symptom severity (SANS for negative symptoms, BPRS for positive and depression/anxiety symptoms) and psychosocial functioning (SOFAS, GAF, QLS) at baseline and follow-up as well as similar prevalence of non-psychotic disorders at follow-up. Our findings demonstrate that UHR groups evidence a similar clinical risk profile when we expand this beyond transition to psychosis, and consequently support maintaining the existing UHR criteria.