Innate immunity: Looking beyond T-cells in radiation and immunotherapy combinations

Radiation therapy is an established and effective anti-cancer treatment modality. Extensive pre-clinical experimentation has demonstrated that the pro-inflammatory properties of irradiation may be synergistic with checkpoint immunotherapy. Radiation induces double-stranded DNA breaks (dsDNA). Sensing of the dsDNA activates the cGAS/STING pathway, producing Type 1 interferons essential to recruiting antigen-presenting cells (APCs). Radiation promotes cytotoxic CD8 T-cell recruitment by releasing tumour-associated antigens captured and cross-presented by surveying antigen-presenting cells. Radiation-induced vascular normalisation may further promote T-cell trafficking and drug delivery. Radiation is also immunosuppressive. Recruitment of regulatory T cells (Tregs) and innate cells such as myeloid-derived suppressive cells (m-MDSCs) all counteract the immunostimulatory properties of radiation. Many innate immune cell types operate at the interface of the adaptive immune response. Innate immune cells, such as m-MDSCs, can exert their immunosuppressive effects by expressing immune checkpoints such as PD-L1, further highlighting the potential of combined radiation and checkpoint immunotherapy. Several early-phase clinical studies investigating the combination of radiation and immunotherapy have been disappointing. A greater appreciation of radiotherapy's impact on the innate immune system is essential to optimise radioimmunotherapy combinations. This review will summarise the impact of radiotherapy on crucial cells of the innate immune system and vital immunosuppressive cytokines.

Extubation Failure in a Burn Intensive Care Unit: Examination of Contributing Factors

Extubation failure is associated with negative outcomes making the identification of risk factors for failure paramount. Burn patients experience a high incidence of respiratory failure requiring mechanical ventilation. There is no consensus on the acceptable rate of extubation failure and many conventional indices do not accurately predict extubation outcomes in burn patients. The purpose of this study was to examine the rate of extubation failure in the burned population and to examine the impact of factors on extubation outcomes. Burn patients from a single center over 9 years were examined and included if they were intubated prior to arrival or within 48 hours of admission and underwent a planned extubation. From this cohort, a matched case-control analysis based on age, TBSA, and sex was performed of patients who succeeded after extubation, defined as not requiring reintubation within 72 hours, to those who failed. Characteristics and clinical parameters were compared to determine whether any factors could predict extubation failure. There was a 12.3% incidence of extubation failure. In the matched case-control analysis, the presence of inhalation injury was associated with extubation success. Higher heart rate and lower serum pH were associated with extubation failure. ANCOVA analysis demonstrated that a sodium trending higher before extubation was associated with more successes, possibly indicative of a lower volume status. Classic extubation criteria do not accurately predict extubation outcomes in burn patients; analysis of other parameters may be able to provide better predictions. A constellation of these parameters needs to be studied prospectively.

Single-Fraction Stereotactic Body Radiation Therapy: A Paradigm During the Coronavirus Disease 2019 (COVID-19) Pandemic and Beyond?

PURPOSE

Owing to the coronavirus disease 2019 (COVID-19) pandemic, radiation oncology departments have adopted various strategies to deliver radiation therapy safely and efficiently while minimizing the risk of severe acute respiratory syndrome coronavirus-2 transmission among patients and health care providers. One practical strategy is to deliver stereotactic body radiation therapy (SBRT) in a single fraction, which has been well established for treating bone metastases, although it has been infrequently used for other extracranial sites.

METHODS AND MATERIALS

A PubMed search of published articles in English related to single-fraction SBRT was performed. A critical review was performed of the articles that described clinical outcomes of single-fraction SBRT for treatment of primary extracranial cancers and oligometastatic extraspinal disease.

RESULTS

Single-fraction SBRT for peripheral early-stage non-small cell lung cancer is supported by randomized data and is strongly endorsed during the COVID-19 pandemic by the European Society for Radiotherapy and Oncology-American Society for Radiation Oncology practice guidelines. Prospective and retrospective studies supporting a single-fraction regimen are limited, although outcomes are promising for renal cell carcinoma, liver metastases, and adrenal metastases. Data are immature for primary prostate cancer and demonstrate excess late toxicity in primary pancreatic cancer.

CONCLUSIONS

Single-fraction SBRT should be strongly considered for peripheral early-stage non-small cell lung cancer during the COVID-19 pandemic to mitigate the potentially severe consequences of severe acute respiratory syndrome coronavirus-2 transmission. Although single-fraction SBRT is promising for the definitive treatment of other primary or oligometastatic cancers, multi-fraction SBRT should be the preferred regimen owing to the need for additional prospective evaluation to determine long-term efficacy and safety.

Preinjury statin use and thromboembolic events in trauma: a 10-year retrospective evaluation

BACKGROUND

Traumatic injury is well known to increase the risk of venous thromboembolic events (VTEs), occurring in up to 58% of trauma patients. Statin medications have significant anti-inflammatory properties and have been shown to reduce the risk of VTE. We hypothesized that trauma patients who received statin medication before injury would have a lower incidence of VTE after injury.

METHODS

A 10-y retrospective review identified all patients admitted to our trauma service with an injury severity score >9 and an intensive care unit stay of >3 d. This population was categorized as either "statin recipient" (SR) or "statin naïve," with subsequent categorical division by occurrence of VTE. Our primary outcome measure was the occurrence of documented VTE in both statin naïve and SR subjects.

RESULTS

A total of 2519 trauma patients were included with 97 (3.8%) developing VTE. Pretrauma statin use in males remained as an independent predictor of VTE (odds ratio = 2.25, 95% confidence interval = 1.25-4.04, P < 0.01). The median time to VTE onset was 3 d longer in SRs (10.0 d; confidence interval = 7.3-12.7, P < 0.05).

CONCLUSIONS

Pretrauma statin use does not appear to have a protective benefit of VTE prevention in trauma patients, as we have shown pretrauma SR male trauma patients to have a twofold increased incidence of VTE. However, when considering the 3 d longer median time to VTE onset found in SRs, we consider the protective benefit of statin use reported in the current literature as likely attributable to this observed delayed onset.

Accuracy of patient-specific instrumentation in anatomic and reverse total shoulder arthroplasty

PURPOSE

Glenoid component malposition is associated with poor function and early failure of both anatomic and reverse total shoulder arthroplasty. Glenoid positioning is challenging particularly in the setting of bone loss or deformity. Recently, the use of computer assistance has been shown to reduce implantation error. The aim of this study is to evaluate the accuracy of patient-specific instrumentation in cases of anatomic and reverse shoulder replacement in vivo.

METHODS

Twenty patients underwent total shoulder arthroplasty using a computed tomography (CT)-based patient-specific instrumentation (PSI) system, ten anatomic and ten reverse. Preoperative three-dimensional digital templating of glenoid component position was undertaken and surgery then performed using a custom-made guide. Postoperative CT scans were used to compare final implanted component position to the preoperatively planned position in the same patient.

RESULTS

Final component position and orientation closely reflected the preoperatively templated position. Mean deviation in the glenoid version from planned was 1.8° ±1.9° (range, 0.1°-7.3°). Mean deviation in inclination was 1.3° ±1.0° (range, 0.2°-4.5°). Mean deviation in position on the glenoid face was 0.5 ± 0.3 mm (range, 0.0-1.3 mm) in the anteroposterior plane and 0.8 ± 0.5 mm (range, 0.0-1.9 mm) in the superoinferior plane. Actual achieved version was within 7° of neutral in all cases except for one where it was deliberately planned to be outside of this range.

CONCLUSION

PSI in both anatomic and reverse shoulder arthroplasty is highly accurate in guiding glenoid component implantation in vivo. The system can reliably correct bony deformity.

Functional coupling of a recombinant human 5-HT5A receptor to G-proteins in HEK-293 cells

1. We have cloned, expressed and pharmacologically characterized the Human 5-HT5A receptor. 2. We have shown that ligand activation of the Human 5-HT5A receptor results in functional coupling to G-proteins in HEK-293 cells. 3. Stimulation of the receptor with 5-CT (5-carboxamidotryptamine) resulted in a dose-dependent increase in the % [35S]-GTPgammaS binding over the basal level. This is the first study to describe such G-protein activation for the Human 5-HT5A receptor in any cell. 4. A dose-dependent inhibition of cyclic AMP accumulation was observed in the recombinant Human 5-HT5A receptor cell line, suggesting a functional coupling to a G alpha i, G-protein in the HEK-293 cell line. 5. A ligand-stimulated reduction in the detectable level of the catalytic domain of protein kinase A (PKA) in nuclear extracts isolated from Human 5-HT5A expressing cells was observed. This observation was consistent with the reduction in the level of cyclic AMP accumulation, in response to receptor activation.