Improving extracellular vesicles production through a Bayesian optimization-based experimental design.

With the growing demand and diversity of biological drugs, developing optimal processes for their accelerated production with minimal resource utilization is a pressing challenge. Typically, such optimization involves multiple target properties, such as production yield, biological activity, and product purity. Therefore, strategic experimental design techniques that can characterize the parameter space while simultaneously arriving at the optimal process satisfying multiple target properties are required. To achieve this, we propose the use of a multi-objective batch Bayesian optimization (MOBBO) algorithm and illustrate its successful application for the production of extracellular vesicles (EVs) from a 3D culture of mesenchymal stem cells (MSCs) considering three objectives, namely to maximize the vesicle-to-protein ratio, maximize the enzymatic activity of the MSC-EV protein CD73, and minimize the amount of calregulin impurities. We show that the optimal combination of the process parameters to address the intended objectives could be achieved with only 32 experiments. For the four parameters considered (i.e., microcarrier concentration, seeding density, centrifugation time, and impeller speed), this number of experiments is comparable to or lower than the classical design of experiments (DoE) and the traditional one-factor-at-a-time (OFAT) approach. We illustrate how the algorithm adaptively samples in the process parameter space, selectively excluding unfavorable regions, thus minimizing the number of experiments required to reach optimal conditions. Finally, we compare the obtained solutions to the literature data and present possible applications of the collected data for other modeling activities such as Quality by Design, process monitoring, control, and scale-up.

Regional anesthesia prevents cancer recurrence after oncosurgery! What is wrong with the hypothesis?

Several studies have investigated the hypothesis of the efficacy of regional anesthesia (RA) techniques in preventing cancer recurrence when used perioperatively during oncological surgeries. Although theoretically, the association appears beneficial, the patient outcomes after cancer surgeries with or without RA were comparable, that is, the use of RA did not improve patient survival or prevent cancer recurrence after surgery. Another problem with this data is its retrospective nature which makes its interpretation difficult. Moreover, there are a lot of other confounding factors like comorbidities, tumor biology, nosocomial infections, duration of hospital stay, and baseline immunity, which is not comparable, and hence make standardization for a well-designed prospective study difficult. Return to intended oncologic therapy (RIOT) involves treatment in the form of radiation or chemotherapy which, if received on time after the planned oncosurgery, could provide a better chance of preventing cancer recurrence and improved survival. However, none of the retrospective studies have correlated cancer recurrence with delay in RIOT or not receiving RIOT as a cause of cancer recurrence. This paper discusses why even a well-designed, prospective trial could possibly never establish the efficacy of RA in preventing cancer recurrence and improving survival due to the complexities involved in a patient undergoing oncosurgery.

Single-Dose Prophylactic Antibiotic Versus Extended Usage for Four Days in Clean-Contaminated Oncological Surgeries: a Randomized Clinical Trial.

The optimal duration of prophylactic antimicrobial usage in clean-contaminated elective oncological surgeries is not clear. This single-center randomized trial evaluated the effectiveness of single-dose antimicrobial prophylaxis in clean-contaminated surgeries for the reduction of surgical site infection (SSI). Between April 2018 and January 2019, 315 patients undergoing major oncological clean-contaminated surgeries where the gastrointestinal or genital tract was opened under controlled conditions were randomized into 2 groups i.e., single dose versus extended dose groups. The single dose group received a 1.5 g dose of cefuroxime immediately before surgery while the extended group received the same dose of cefuroxime thrice daily for 4 days from the day of surgery till postoperative day 3. In addition, patients undergoing esophageal and colorectal surgeries received metronidazole. The overall SSI rate of the single dose group was not significantly different from that of the extended group (11.3% vs. 14.7%, respectively, p 0.40), with absolute difference of 3.4% and relative risk of 0.85 (95% C.I, 0.59 to 1.22). The rate of remote site infection was also not different between the two groups (14.4% vs 10.2%, p 0.31) with absolute difference of 4.2% and relative risk 1.19 (95% C.I, 0.89 to 1.59). In univariate analysis, parameters like nodal dissection, colorectal surgery, smoking, and hospital stay were significantly associated with SSI. In multivariate analysis, age, smoking, nodal dissection, and hospital stay retained significance. Single-dose antimicrobial prophylaxis is as effective as extended usage for 4 days in the prevention of postoperative SSI in patients undergoing clean-contaminated major oncological surgeries. Trial was registered with the clinical trial registry of India (CTRI/2018/06/014344).