Hyperthermia induced by transient receptor potential vanilloid-1 (TRPV1) antagonists in human clinical trials: Insights from mathematical modeling and meta-analysis

Antagonists of the transient receptor potential vanilloid-1 (TRPV1) channel alter body temperature (T_b) in laboratory animals and humans: most cause hyperthermia; some produce hypothermia; and yet others have no effect. TRPV1 can be activated by capsaicin (CAP), protons (low pH), and heat. First-generation (polymodal) TRPV1 antagonists potently block all three TRPV1 activation modes. Second-generation (mode-selective) TRPV1 antagonists potently block channel activation by CAP, but exert different effects (e.g., potentiation, no effect, or low-potency inhibition) in the proton mode, heat mode, or both. Based on our earlier studies in rats, only one mode of TRPV1 activation - by protons - is involved in thermoregulatory responses to TRPV1 antagonists. In rats, compounds that potently block, potentiate, or have no effect on proton activation cause hyperthermia, hypothermia, or no effect on T_b, respectively. A T_b response occurs when a TRPV1 antagonist blocks (in case of hyperthermia) or potentiates (hypothermia) the tonic TRPV1 activation by protons somewhere in the trunk, perhaps in muscles, and - via the acido-antithermogenic and acido-antivasoconstrictor reflexes - modulates thermogenesis and skin vasoconstriction. In this work, we used a mathematical model to analyze T_b data from human clinical trials of TRPV1 antagonists. The analysis suggests that, in humans, the hyperthermic effect depends on the antagonist's potency to block TRPV1 activation not only by protons, but also by heat, while the CAP activation mode is uninvolved. Whereas in rats TRPV1 drives thermoeffectors by mediating pH signals from the trunk, but not T_b signals, our analysis suggests that TRPV1 mediates both pH and thermal signals driving thermoregulation in humans. Hence, in humans (but not in rats), TRPV1 is likely to serve as a thermosensor of the thermoregulation system. We also conducted a meta-analysis of T_b data from human trials and found that polymodal TRPV1 antagonists (ABT-102, AZD1386, and V116517) increase T_b, whereas the mode-selective blocker NEO6860 does not. Several strategies of harnessing the thermoregulatory effects of TRPV1 antagonists in humans are discussed.

Allogenic Blood Transfusion Is an Independent Predictor of Poorer Peri-operative Outcomes and Reduced Long-Term Survival after Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: a Review of 936 Cases

INTRODUCTION

There is a paucity of data on the impact of allogenic blood transfusion (ABT) on morbidity and survival outcomes after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC).

METHODS

Nine hundred and thirty-five consecutive CRS/HIPEC procedures were performed between 1996 and 2016 at a high-volume institution in Sydney, Australia. Of these, 337(36%) patients required massive ABT (MABT) (≥5 units). Peri-operative complications were graded according to the Clavien-Dindo classification. The association of concomitant MABT with 21 peri-operative outcomes and overall survival (OS) was assessed using univariate and multivariate analyses.

RESULTS

In-hospital mortality was 1.8%. Patients requiring MABT had more extensive disease as reflected by a higher peritoneal cancer index (≥17) (70 vs. 29%, p < 0.001) and longer operative times (≥9 h) (82 vs. 35%, p < 0.001). After accounting for confounding factors, MABT was associated with in-hospital mortality (relative risk (RR), 7.72; 95% confidence interval (CI), 1.35-10.11; p = 0.021) and grade III/IV morbidity (RR, 2.05; 95% CI, 1.42-2.95; p < 0.001). MABT was associated with an increased incidence of prolonged hospital stay (≥28 days) (RR, 1.86; 95% CI, 1.26-2.74; p = 0.002) and intensive care unit stay (≥4 days) (RR, 1.83; 95% CI, 1.24-2.70, p = 0.002). It was also associated with a significant OS in patients with colorectal cancer peritoneal carcinomatosis (RR 4.49; p < 0.001) and pseudomyxoma peritonei (RR, 4.37; p = 0.026), but not appendiceal cancer (p = 0.160).

CONCLUSION

MABT is an independent predictor for poorer peri-operative outcomes including in-hospital mortality and grade III/IV morbidity. It may also compromise long-term survival, particularly in patients with colorectal cancer peritoneal carcinomatosis.

Critical care management and intensive care unit outcomes following cytoreductive surgery with hyperthermic intraperitoneal chemotherapy

AIM

To study the early postoperative intensive care unit (ICU) management and complications in the first 2 wk of patients undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

Our study is a retrospective, observational study performed at Icahn School of Medicine at Mount Sinai, quaternary care hospital in New York City. All adult patients who underwent CRS and HIPEC between January 1, 2007 and December 31, 2012 and admitted to ICU postoperatively were studied. Fifty-one patients came to the ICU postoperatively out of 170 who underwent CRS and HIPEC therapy during the study period. Data analysis was performed using descriptive statistics.

RESULTS

Of the 170 patients who underwent CRS and HIPEC therapy, 51 (30%) came to the ICU postoperatively. Mean ICU length of stay was 4 d (range 1-60 d) and mean APACHE II score was 15 (range 7-23). Thirty-one/fifty-one (62%) patients developed postoperative complications. Aggressive intraoperative and postoperative fluid resuscitation is required in most patients. Hypovolemia was seen in all patients and median amount of fluids required in the first 48 h was 6 L (range 1-14 L). Thirteen patients (25%) developed postoperative hypotension with seven requiring vasopressor support. The major cause of sepsis was intraabdominal, with 8 (15%) developing anastomotic leaks and 5 (10%) developing intraabdominal abscess. The median survival was 14 mo with 30 d mortality of 4% (2/51) and 90 d mortality of 16% (8/51). One year survival was 56.4% (28/51). Preoperative medical co morbidities, extent of surgical debulking, intraoperative blood losses, amount of intra op blood products required and total operative time are the factors to be considered while deciding ICU vs non ICU admission.

CONCLUSION

Overall, ICU outcomes of this study population are excellent. Triage of these patients should consider preoperative and intraoperative factors. Intensivists should be vigilant to aggressive postop fluid resuscitation, pain control and early detection and management of surgical complications.

Then and now: cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC), a historical perspective

The management of peritoneal carcinomatosis, once considered a condition with few therapeutic options, has undergone dramatic change with the advancement of surgical techniques and systemic cancer therapy. Cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC) administration, in particular, has significantly impacted the prospect of improving outcomes for this debilitating presentation of malignancy in selected patients. This regional surgical therapy itself has undergone many stages of evolution through its original conception nearly a century ago. Progressive changes in this field have included refinements and ongoing standardization in technique, development of a common language to describe tumor burden and extent of resection, better selection of chemotherapeutics based on tumor histology, reduction of surgical morbidity and mortality, and an improved understanding of factors for appropriate patient selection, to list but a few examples. CRS/HIPEC continues to play an important role in the management of select patients with carcinomatosis of certain tumor histology and its role will no doubt continue to be redefined as new therapies emerge.

Quality of life after cytoreductive surgery and hyperthermic intra-peritoneal chemotherapy for peritoneal carcinomatosis: A systematic review and meta-analysis

OBJECTIVE

To review the effect of cytoreductive surgery (CRS) and hyperthermic intra-peritoneal chemotherapy (HIPEC) on health-related quality of life (HRQOL) in patients with peritoneal carcinomatosis.

BACKGROUND

CRS and HIPEC is increasingly performed with curative intent for peritoneal carcinomatosis. Significant morbidity rates are reported in the context of limited life-expectancy, necessitating accurate post-operative HRQOL outcome data.

METHODS

A systematic review of clinical studies published after January 2000 was performed using strict eligibility criteria. Key outcomes measures were post-operative HRQOL compared to pre-operative levels and reference populations. Quality appraisal and data tabulation were performed using pre-determined forms. Data were synthesised by narrative review and random-effects meta-analysis. Tau2 and I2 values and Funnel plots were analysed for consistency and bias.

RESULTS

15 studies (1583 patients) were included. HRQOL declines at the 3-4 month time-point before becoming similar or better compared to pre-operative levels at 1 year. The pooled-effects of combined post-operative functional assessment of cancer therapy and European organisation for research and treatment quality of life questionnaire scores were significantly improved from baseline on overall health status (p=0.001) and emotional health (p=0.001). Physical health (p=0.83), social health (p=0.48) and functional health (p=0.24) remain similar. HRQOL after 1 year is less clear, but benefits may persist up to 5 years especially on overall and physical health domains. Evidence is conflicted and inconclusive on HRQOL compared to reference populations. Levels of consistency and bias were acceptable.

CONCLUSIONS

CRS and HIPEC for peritoneal carcinomatosis can confer small to medium benefits for HRQOL. These results should be interpreted with in caution due to the small studies and absence of more randomised controlled trials.

Heat stress promotes skeletal muscle regeneration after crush injury in rats

Influences of heat stress on skeletal muscle regeneration were examined in experimental rats. After crush injury to the Extensor digitorum longus muscle (EDL) of the left hindlimb, animals were randomly divided into non-heat and heat groups. In the latter, packs filled with hot water (42°C) were percutaneously applied to the injured EDL muscle for 20min to the front of the lower leg, soon after the injury. During the early stages of muscle regeneration, due to the heat stress, secondary degeneration at the injured site progressed faster, and migration of macrophages, proliferation and differentiation of satellite cells were facilitated. At 14 and 28 days after the injury, the ratio of regenerating muscle fibers exhibiting central nuclei in the heat treated group was significantly lower than that in the non-heat group, and cross sectional area in the heat group was evidently larger than that in the non-heat group. Moreover, in the heat group, the ratio of collagen fiber area at 14 and 28 days after the injury was smaller than in the non-heat group. Together, these findings suggest that acceleration of degeneration processes by heat stress soon after injury is likely to promote skeletal muscle regeneration and inhibit collagen deposition.