Equilibrium ex vivo calibration of homogenized tissue for in vivo SPME quantitation of doxorubicin in lung tissue.

The fast and sensitive determination of concentrations of anticancer drugs in specific organs can improve the efficacy of chemotherapy and minimize its adverse effects. In this paper, ex vivo solid-phase microextraction (SPME) coupled to LC-MS/MS as a method for rapidly quantitating doxorubicin (DOX) in lung tissue was optimized. Furthermore, the theoretical and practical challenges related to the real-time monitoring of DOX levels in the lung tissue of a living organism (in vivo SPME) are presented. In addition, several parameters for ex vivo/in vivo SPME studies, such as extraction efficiency of autoclaved fibers, intact/homogenized tissue differences, critical tissue amount, and the absence of an internal standard are thoroughly examined. To both accurately quantify DOX in solid tissue and minimize the error related to the lack of an internal standard, a calibration method at equilibrium conditions was chosen. In optimized ex vivo SPME conditions, the targeted compound was extracted by directly introducing a 15 mm (45 µm thickness) mixed-mode fiber into 15 g of homogenized tissue for 20 min, followed by a desorption step in an optimal solvent mixture. The detection limit for DOX was 2.5 µg g-1 of tissue. The optimized ex vivo SPME method was successfully applied for the analysis of DOX in real pig lung biopsies, providing an averaged accuracy and precision of 103.2% and 12.3%, respectively. Additionally, a comparison between SPME and solid-liquid extraction revealed good agreement. The results presented herein demonstrate that the developed SPME method radically simplifies the sample preparation step and eliminates the need for tissue biopsies. These results suggest that SPME can accurately quantify DOX in different tissue compartments and can be potentially useful for monitoring and adjusting drug dosages during chemotherapy in order to achieve effective and safe concentrations of doxorubicin.

Extension of donor lung preservation with hypothermic storage after normothermic ex vivo lung perfusion.

BACKGROUND: Ex vivo lung perfusion (EVLP) allows normothermic evaluation and treatment of donor lungs not currently acceptable for transplant and improves organ use. Donor lungs undergo a period of cold preservation before (cold ischemic time [CIT]-1) and after (CIT-2) EVLP. We investigated the effect of an extended CIT-2 on lung function after transplantation. METHODS: Explanted pig lungs, preserved in low-potassium dextran flush (Perfadex) at 4°C for 10 hours, were subjected to 6 hours of EVLP. They were subsequently allocated to 2 groups: short CIT-2 (CIT-2 = 2 hours; n = 5), and long CIT-2 (CIT-2 = 10 hours; n = 5). In a control group (n = 6), explanted lungs were placed in cold static preservation for 24 hours without EVLP. After the total preservation period, the left lung was transplanted in all groups. RESULTS: After 4 hours of reperfusion, oxygenation function, acute lung injury score, inflammatory markers, and cell death pathway markers were similar between short and long CIT-2 groups. Both EVLP groups fared significantly better than the control group in oxygenation function (p < 0.05). CONCLUSIONS: The intervention of EVLP improved lung function after transplantation, and this was not affected by a prolonged cold static preservation time after EVLP. These results provide the basis for a practical prolonged lung preservation strategy using a combination of cold and warm preservation techniques, which may improve lung transplantation logistics and outcomes.

Modified in vivo lung perfusion allows for prolonged perfusion without acute lung injury.

OBJECTIVES: In vivo lung perfusion (IVLP) is an emergent strategy to treat lung metastases because it allows localized delivery of chemotherapy with minimal systemic exposure. Previously, short-term (± 30 minutes) IVLP resulted in variable efficacy and significant lung toxicity. We hypothesize that a modified IVLP strategy derived from an ex vivo lung perfusion technique could minimize lung injury. Our objective was to demonstrate the feasibility and safety of a modified prolonged (4 hours) IVLP. METHODS: Six Yorkshire pigs were used for the experiments. A thoracotomy was performed, the left pulmonary artery and pulmonary veins were cannulated, and the left lung was isolated in situ. IVLP was performed at normothermia for 4 hours using Steen Solution (XVIVO Perfusion, Göteburg, Sweden) as perfusate. The flow rate was 16% of estimated cardiac output and left atrial pressure was maintained between 3 and 5 mm Hg. Perfusate was deoxygenated and supplied with CO2 to physiologic levels before entering the lungs. A protective mode of ventilation was used. After IVLP, the left lung was allowed to reperfuse for additional 4 hours. Airway dynamics, gas exchange, and pulmonary vascular resistance were used to assess left lung physiology. Histologic signs of lung injury were assessed before and after IVLP, and 4 hours after reperfusion. RESULTS: Lung function parameters were stable throughout the 4-hour IVLP and during reperfusion. No significant histologic evidence of acute lung injury was observed. CONCLUSIONS: Four hours of IVLP is feasible without adding significant lung injury. Prolonged perfusion time and a protective protocol might provide safer and more efficacious treatment of pulmonary metastases.