Microstructure and in vivo characterization of multi-channel nerve guidance scaffolds

In a previous study, we demonstrated a novel manufacturing approach to fabricate multi-channel scaffolds (MCS) for use in spinal cord injuries (SCI). In the present study, we extended similar materials processing technology to fabricate significantly longer (5X) porous poly caprolactone (PCL) MCS and evaluated their efficacy in 1 cm sciatic peripheral nerve injury (PNI) model. Due to the increase in MCS dimensions and the challenges that may arise in a longer nerve gap model, microstructural characterization involved MCS wall permeability to assess nutrient flow, topography, and microstructural uniformity to evaluate the potential for homogeneous linear axon guidance. It was determined that the wall permeability dramatically varied from 0.02 ± 0.01 × 10^-13 to 21.7 ± 11.4 × 10^-13 m² for 50% and 70% porous PCL, respectively. Using interferometry, the porous PCL surface roughness was determined to be 10.7 ± 1.2 μm, which is believed to be sufficient to promote cell integration. Using micro computed tomography, the 3D MCS microstructure was determined to be uniform over 1 cm with an open lumen volume of 44.6% ± 3.6%. In vivo implantation, in the rat sciatic nerve model, over 4 weeks, demonstrated that MCS scaffolds maintained structural integrity, were biocompatible, and supported linear axon guidance and distal end egress over 1 cm. Taken together, this study demonstrated that MCS technology previously developed for the SCI is also relevant to longer nerve gap PNI.

Abstract OT2-01-01: Observational study of axilla treatment for breast cancer patients with 1 to 3 positive micrometastases or macrometastases in sentinel lymph nodes

[Background] Axilla surgery in node-positive breast cancer is dramatically changing from axillary lymph node dissection (ALND) to sentinel node biopsy (SNB). From the results of ACOSOG Z0011, IBCSG23-01 and AMAROS trials, adjuvant therapy and regional node irradiation could reduce regional lymph node recurrence for sentinel node-positive breast cancer patients. However, optimal indication of SNB alone remains uncertain. Trial design: To evaluate the outcome of sentinel node-positive breast cancer patients, the Japanese Society for Sentinel Node Navigation Surgery (SNNS) conducted a prospective cohort study in 2013 (UMIN000011782, Jpn J Clin Oncol, p.876-9, 2014). [Eligibility criteria] For eligible patients, SNB was performed or scheduled after 1 January 2012. Then 1 to 3 positive micrometastases or macrometastases in sentinel lymph nodes are confirmed by histological or molecular diagnosis. Primary chemotherapy before or after SNB is also acceptable for registration. [Specific aims] The primary endpoint is the 5-year recurrence rate of regional lymph node in patients treated with SNB alone. The secondary endpoint is the 5-year overall survival rate of this cohort. Patients treated with SNB followed by ALND are also registered simultaneously to compare the prognosis. The propensity score matching (PSM) is used to make the distributions of baseline risk factors comparable. [Statistical method] Based on an estimated recurrence rate of 5% at 5 years among patients treated with SNB alone, 240 patients are needed to give a 80% power to reject the null hypothesis that the recurrence rate is 10% with a one-sided type I error rate of 2.5%. If we consider that some patients will be lost to follow-up or become ineligible, a total of 250 patients will be needed to comprise the sample. [Present accrual] Eight hundred and eighty patients who underwent SNB alone or SNB followed by ALND were registered from 27 participating institutes between 2013 and 2016. Data cleaning is being performed. Patient's background and PSM will be reported.

Citation Format: Imoto S, Saito Oba M, Masuda N, Nagashima T, Wada N, Takashima T, Kitada M, Kawada M, Hayashida T, Taguchi T, Aihara T, Miura D, Toh U, Yoshida M, Sugae S, Yoneyama K, Matsumoto H, Jinno H, Sakamoto J. Observational study of axilla treatment for breast cancer patients with 1 to 3 positive micrometastases or macrometastases in sentinel lymph nodes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-01-01.

Physicians’ Choice in Using Internet and Fax for Patient Recruitment and Follow-up in a Randomized Controlled Trial

Objective: To examine the physicians’ preference between Web and fax-based remote data entry (RDE) system for an ongoing randomized controlled trial (RCT) in Japan.

Methods: We conducted a survey among all the collaborating physicians (n = 512) of the CASE-J (Candesartan Antihypertensive Survival Evaluation in Japan) trial, who have been recruiting patients and sending follow-up data using the Web or a fax-based RDE system. The survey instrument assessed physicians’ choice between Web and fax-based RDE systems, their practice pattern, and attitudes towards these two modalities.

Results: A total of 448 (87.5%) responses were received. The proportions of physicians who used Web, fax, and the combination of these two were 45.9%, 33.3% and 20.8%, respectively. Multivariate logistic regression analyses revealed that physicians 55 years or younger [odds ratio (OR) = 1.9, 95% confidence interval (CI) = 1.1-3.3] and regular users of computers (OR = 4.2, 95% CI = 2.1-8.2) were more likely to use the Web-based RDE system.

Conclusions: This information would be useful in designing an RCT with a Web-based RDE system in Japan and abroad.

The influence of aging on the effectiveness of heat stress in preventing disuse muscle atrophy

This study examined the aging effect on disuse muscle atrophy prevention using heat stress. Wistar rats aged 7 and 60 weeks were divided into three groups as follows: control, immobilized (Im), and immobilized and heat stressed (ImH). Heat stress was given by immersing the hindlimbs in hot water (42 °C) for 60 min, once in every 3 days and the gastrocnemius (GAS) and soleus (SOL) muscles were extracted after 14 days. Muscle-fiber types were classified using ATPase staining. Heat shock protein 70 (HSP70) was assessed through Western blotting. In GAS muscle of both groups and SOL muscle of 7-week-old rats, the fiber diameter of each muscle type in the ImH group significantly increased compared with that in the Im group. However, this could not be observed in the SOL muscle of the 60-week-old rats. The increased percentage of type-I fibers and variability of types I and II muscle-fiber diameter were evident in the SOL muscle of the 60-week rats. HSP70 was significantly elevated in the ImH group compared with in the Im group in both muscle types of both age groups. Thus, effectiveness of heat stress in the prevention of disuse muscle atrophy appears unsatisfactory in aging muscle fibers.

Myeloperoxidase in blood neutrophils during normal and abnormal menstrual cycles in women of reproductive age

INTRODUCTION

We previously reported that granulocyte colony-stimulating factor (G-CSF) plays a critical role in ovulation, suggesting that neutrophils may maintain ovulation. We assessed myeloperoxidase (MPO), a major and specific enzyme of neutrophils, in women with abnormal and normal menstrual cycles to clarify the relationship between MPO and ovulation.

METHODS

We analyzed MPO activity in blood neutrophils of women with abnormal menstrual cycles (indicative of anovulation, n = 12) and age- and body mass index-matched normal menstrual cycles (indicative of ovulation, n = 24) using two parameters as a marker of MPO, Neut X and mean peroxidase index (MPXI).

RESULTS

MPO of women with abnormal menstrual cycles was significantly lower than that of women with normal menstrual cycles [Neut X: 62.6 ± 1.1 (mean ± standard error of the mean) vs. 66.2 ± 0.3, P = 0.009; MPXI: -0.54 ± 1.66 vs. 4.91 ± 0.53, P = 0.008]. Among women with normal menstrual cycles, MPO was highest in the follicular phase (Neut X: 67.0 ± 0.3; P = 0.033).

CONCLUSION

The difference in MPO between women with abnormal and normal menstrual cycles and the upregulation of MPO before ovulation suggest that neutrophils and MPO are closely related to ovulation.

Large-scale prospective pharmacogenomics study of oxaliplatin-induced neuropathy in colon cancer patients enrolled in the JFMC41-1001-C2 (JOIN Trial)

BACKGROUND

Peripheral sensory neuropathy (PSN) is a dose-limiting toxicity of oxaliplatin-based chemotherapy. Several genetic markers have been shown to predict oxaliplatin-induced PSN; however, results remain to be validated in a large-scale and prospective pharmacogenomics study.

PATIENTS AND METHODS

Among 882 patients enrolled in the JFMC41-1001-C2 (JOIN trial), which was designed to investigate the tolerability of adjuvant-modified FOLFOX6 (mFOLFOX6) in Japanese Patients with stage II or III colon cancers undergoing curative resection, 465 patients were eligible for this pharmacogenomics analysis. Twelve single-nucleotide polymorphisms (SNPs) were selected based on published data. The effect of each genotype on time to PSN onset was evaluated in all patients (n = 465) using the Cox proportional hazard model. For the association analysis between severity of PSN and 12 SNP markers, 84 patients who failed to complete 12 cycles of mFOLFOX6 from grade 0/1 PSN group were excluded because the termination of the protocol treatment had been caused by reasons other than PSN.

RESULTS

Comparison of grade 0/1 PSN with grade 2/3 PSN or grade 3 PSN showed no significant associations with any of the 12 SNP markers after adjustment for total dose of oxaliplatin. Time-to-onset analysis also failed to reveal any significant differences.

CONCLUSIONS

Our large-scale and prospective pharmacogenomics study of Japanese patients receiving protocol treatment of adjuvant mFOLFOX6 could not verify a role for any of the 12 SNP markers reported as being significantly associated with PSN. Considering the OR observed in this study (range: 0.76-1.89), further evaluation of these 12 SNP markers in the context of L-OHP-induced PSN is unlikely to be clinically informative.