Toward Transpulmonary Chemoembolization with Degradable Starch Microspheres: Systematic Analysis of Local and Systemic Effects in a Porcine Model

Assessment of the physiological effects and safety of transpulmonary chemoembolization with doxorubicin on pulmonary tissue using a human-isolated lung perfusion model

BACKGROUND

Whole lung transpulmonary chemoembolization using a combination of doxorubicin (DXO) and degradable starch microspheres (DSM-TPCE) might be a promising treatment option in soft tissue sarcoma. To pave the way for clinical studies, this study aimed to evaluate the short-term effects of DSM-TPCE with DXO using an ex vivo isolated lung perfusion (ILP) model.

METHODS

Nine lung specimens retrieved from patients undergoing lobectomy underwent ex vivo ILP. In groups of three, lung specimens were either treated with sole DXO, sole DSM, or combined substances (DSM + DXO). During ex vivo ILP, histological samples were obtained from each lung every 15 min. Quantitative DXO analysis and histopathological grading of possible tissue damage using a five-point Likert scale was performed. Two-way repeated measures ANOVA tested for differences between treatment groups and changes over time.

RESULTS

We created a preclinical ex vivo ILP model to simulate the effects of DSM-TPCE. In histopathological analysis, only two specimens, treated with only DXO, showed an increase in parenchymal damage over time. No significant effect of time (3.3%, p = 0.305) or group (23.3; p = 0.331) was identified. Within the lung tissue, the DXO concentration ranged from 205 to 1,244 ng/g. No significant effects could be detected regarding different treatment groups (4.9% of total variation, p = 0.103).

CONCLUSION

In an ex vivo ILP model using human lung lobes, the physiological effects of DSM-TPCE with DXO could be tested. Neither increased DXO concentrations in lung tissue nor histopathological changes indicating early lung toxicity were observed.

RELEVANCE STATEMENT

An ex vivo ILP model using human lung specimens did not show any signs of early lung toxicity after transpulmonary chemoembolization with DXO. These results support further evaluation of DSM-TPCE in phase I/II trials.

KEY POINTS

Transpulmonary chemoembolization can be investigated in an ex vivo ILP model. DSM did not increase DXO in normal lung tissue. DSM did not increase parenchymal toxicity compared to the control groups.

Reversible occlusion of the pulmonary vasculature by transarterial embolisation with degradable starch microspheres: preclinical assessment in a human isolated lung perfusion model

BACKGROUND

Transpulmonary embolisation (TPE) using degradable starch microspheres (DSM) is a potential approach to treat pulmonary metastases. However, there is a paucity of detailed information on perfusion dynamics. The aim of this study was to establish a human ex vivo isolated lung perfusion (ILP) model to observe and evaluate the effects of DSM-TPE in a near-physiologic setting.

METHODS

ILP was carried out on six surgically resected lung lobes. At baseline, computed tomography (CT), including CT perfusion imaging (CTPI), and histopathological sampling were performed (t30). DSM-TPE was initiated and increased stepwise (t45, t60, t75, and t90) to be followed by CT imaging, histopathological sampling, and pulmonary arterial pressure (PAP). After the last assessment (t90), alpha-amylase was injected into the pulmonary artery to allow for DSM hydrolysation and two additional assessments (t105; t120). Histopathological specimens were evaluated using a semiquantitative ordinal score. CTPI was used for time to peak (TTP) analysis.

RESULTS

After DSM administration, PAP and TTP increased significantly: PAP slope 95% confidence interval (CI) 0.104-0.483, p = 0.004; TTP t30 versus t45, p = 0.046. After the addition of alpha-amylase, functional parameters reverted to values comparable to baseline. In histopathological samples, embolisation grades increased significantly until t90 (slope 95% CI 0.027-0.066, p < 0.001) and decreased after addition of alpha-amylase (slope 95% CI -0.060-0.012, p = 0.165), CONCLUSIONS: The ILP model demonstrated successfully both the physiologic effect of DSM-TPE on human lungs and its reversibility with alpha-amylase. Thus, it can be used as a near-physiologic preclinical tool to simulate and assess later clinical approaches.