Serial plasma choline measurements after cardiac arrest in patients undergoing mild therapeutic hypothermia: a prospective observational pilot trial

NMR-based metabolomics in real-time monitoring of treatment induced toxicity and cachexia in head and neck cancer: a method for early detection of high risk patients

INTRODUCTION

Nutritional treatment in head and neck squamous cell carcinoma cancer (HNSCC) patients undergoing radio-/chemo-radiotherapy (RT/CHRT) is complex and requires a multidisciplinary approach. In this study the real-time dynamic changes in serum metabolome during RT/CHRT in HNSCC patients were monitored using NMR-based metabolomics.

OBJECTIVES

The main goal was to find the metabolic markers that could help prevent of acute radiation sequelae (ARS) escalation.

METHODS

170 HNSCC patients were treated radically with RT/CHRT. Blood samples were collected weekly, starting from the day before the treatment and stopping within the week after the RT/CHRT completion, resulting in a total number of 1328 samples. 1H NMR spectra were acquired on Bruker 400 MHz spectrometer at 310 K and analyzed using principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Additional statistical analyses were performed on the quantified metabolites.

RESULTS

PCA has detected a group of distinct outliers corresponding to ketone bodies (3HB, Ace, AceAce). These outliers were found to identify the individuals at high risk of weight loss, mainly by the 3HB changes, which was confirmed by the patients' medical data. In the OPLS-DA models a transition from the lowest to the highest weight loss is seen, defining the metabolic time trajectories for the patients from the studied groups during RT/CHRT. 3HB is a relatively sensitive marker that allows earlier identification of the patients at higher risk of > 10% weight loss.

CONCLUSION

Our findings indicate that metabolic alterations, characteristic for malnutrition or cachexia, can be detected already at the beginning of the treatment, making it possible to monitor the patients with a higher risk of weight loss.

Measurement of plasma choline in acute coronary syndrome: importance of suitable sampling conditions for this assay

Blood choline has been proposed as a predictor of acute coronary syndrome (ACS), however different testing procedures might affect the choline concentration because the lysophospholipase D activity of autotaxin (ATX) can convert lysophosphatidylcholine to lysophosphatidic acid (LPA) and choline in human blood. Although the influences of ATX on LPA levels are well known in vivo and in vitro, those on choline have not been elucidated. Therefore, we established suitable sampling conditions and evaluated the usefulness of plasma choline concentrations as a biomarker for ACS. Serum LPA and choline concentrations dramatically increased after incubation depending on the presence of ATX, while their concentrations in plasma under several conditions were differently modulated. Plasma choline levels in genetically modified mice and healthy human subjects, however, were not influenced by the ATX level in vivo, while the plasma LPA concentrations were associated with ATX. With strict sample preparation, the plasma choline levels did not increase, but actually decreased in ACS patients. Our study revealed that ATX increased the choline concentrations after blood sampling but was not correlated with the choline concentrations in vivo; therefore, strict sample preparation will be necessary to investigate the possible use of choline as a biomarker.

Influence of core body temperature on Tryptophan metabolism, kynurenines, and estimated IDO activity in critically ill patients receiving target temperature management following cardiac arrest

BACKGROUND/AIMS

Temperature control improves neurological prognosis in comatose cardiac arrest (CA) survivors. Previous reports demonstrate that most affected patients show signs of significant systemic inflammation. In an effort to better characterize potential temperature-related effects on key inflammatory pathways, we investigate the course of Tryptophan (Trp) levels, Tryptophan catabolites (including kynurenines) and indoleamine-2,3-dioxygenase (IDO)-activity in post CA patients.

MATERIAL/METHODS

In an observational blinded endpoint analysis, a total of n=270 serial samples from 20 post CA patients (63.1±16.6 yrs., 45% shockable rhythm, mean time to return of spontaneous circulation (ROSC) 26.6±16.0min) treated with target temperature management (TTM) were analyzed. Core body temperatures, course of Trp, Trp catabolites (incl. kynurenines), and estimated IDO-activity were followed up for a maximum of 7 days after ROSC. Patients were followed up until hospital discharge or death and functional outcome was recorded.

RESULTS

Over the 7-day observational interval, marked changes in Trp serum levels and IDO-activity were noted. In general, Trp serum levels but not IDO-activity seemed to parallel with the course of core body temperature. In explorative analyses, a correlation of Trp (rho=0.271 (95%-CI: 0.16-0.38, p<0.0001) and IDO-activity (rho=-0.155, 95%-CI: -0.27 to -0.037, p=0.01) with core body temperature was observed. Linear mixed effect models revealed a positive significant association of core body temperature with Trp serum levels (Likelihood ratio test χ(2)=6.35, p=0.012). In patients with good (vs. unfavorable) outcome, a tendency toward higher Trp serum levels, lower IDO-activity, and lower Kynurenic acid levels was noted.

CONCLUSIONS

We observed significant changes in Trp catabolism and IDO-activity that appeared temperature associated in post CA patients. Under hypothermia, decreased serum levels of Trp and increased IDO-activity were noted. We speculate from our data that IDO-induction during hypothermia contributes to the previously described increased susceptibility to infection or sepsis under reduced temperatures.

Safety, Feasibility, and Hemodynamic Effects of Mild Hypothermia in Transcatheter Aortic Valve Replacement: The TAVR-CHILL Trial

The safety, feasibility, and hemodynamic effects of mild hypothermia (MH) induced by transnasal cooling were studied in transcatheter aortic valve replacement (TAVR). MH is a common therapy following cardiac arrest and seems to have favorable effects in myocardial infarction and on hemodynamic stability. In TAVR, hemodynamic instability is common during rapid pacing. Twenty subjects undergoing TAVR were randomized 1:1 to hypothermia or normothermia. Hemodynamic endpoints were mean arterial blood pressure and required dosage of vasoactive and inotropic drugs. Patients were followed up at 6 months. All patients in the MH group (n=10) reached the target temperature of 34°C before first rapid pacing. Tympanic and urinary bladder temperature remained significantly lower in the MH group during the procedure. No adverse effects of cooling were observed. Mean arterial pressure was higher in the MH group (90±20 mm Hg) than in the control group (71±13 mm Hg) at the start of the procedure, at first rapid pacing (94±19 vs. 80±16 mm Hg), and at balloon aortic valvuloplasty (90±17 vs. 73±14 mm Hg). Less norepinephrine was administered to the hypothermia group. Transnasal cooling during TAVR was safe and well tolerated. We observed a more stable hemodynamic profile in the MH group, indicated by higher blood pressure and lower levels of vasoactive drugs required. A larger study of patients with severe ventricular dysfunction is required to more comprehensively investigate the hemodynamic effects of transnasal cooling in TAVR.