DPPG₂-Based Thermosensitive Liposomes with Encapsulated Doxorubicin Combined with Hyperthermia Lead to Higher Doxorubicin Concentrations in the Bladder Compared to Conventional Application in Pigs: A Rationale for the Treatment of Muscle-Invasive Bladder Cancer

Figures & data

Figure 1 DOX concentrations per group in (A) mucosa, (B) detrusor and (C) serosa. ***p<0.001; **p<0.01; *p < 0.05; n.s.: not significant. Error bars represent standard error of mean.

Abbreviations: DOX, doxorubicin; DPPG₂, 1.2-dipalmitoyl-sn-glycero-3-phosphodiglycerol; HT, hyperthermia; intraves, intravesical; iv, intravenous; TSL, thermosensitive liposomes.

Figure 2 DOX concentrations per group in (A) heart, (B) kidney, (C) liver, (D) spleen and (E) lung. **p<0.01; *p < 0.05. Error bars represent standard error of mean.

Abbreviations: n.s., not significant; DOX, doxorubicin; DPPG₂, 1.2-dipalmitoyl-sn-glycero-3-phosphodiglycerol; HT, hyperthermia; iv, intravenous; TSL, thermosensitive liposomes.

Table 1 DOX Concentrations per Group and Bladder Wall Layer

Group	Mucosa	Detrusor	Serosa
iv DPPG2-TSL-DOX (low dose) + HT	3.29 ± 0.94	1.63 ± 0.34	1.28 ± 0.15
iv DPPG2-TSL-DOX (low dose) + ext. HT	2.91 ± 0.73	1.29 ± 0.25	1.21 ± 0.12
iv DPPG2-TSL-DOX (low dose) - HT	<0.20*	<0.20*	0.24 ± 0.04
iv free DOX (low dose) + HT	0.61 ± 0.15	0.22 ± 0.02	0.37 ± 0.03
iv DPPG2-TSL-DOX (full dose) + HT	25.10 ± 2.74	13.11 ± 1.86	10.33 ± 1.28
intraves DOX (full dose) - HT	9.62 ± 3.77	0.64 ± 0.23	2.33 ± 2.07
intraves DOX (full dose) + HT	4.66 ± 1.11	0.30 ± 0.03	0.36 ± 0.11

Notes: Concentrations are ± standard error of mean in ng/mg; *Represents below limit of quantification.

Abbreviations: DOX, doxorubicin; DPPG₂, 1.2-dipalmitoyl-sn-glycero-3-phosphodiglycerol; HT, hyperthermia; intraves intravesical; iv, intravenous; TSL, thermosensitive liposomes.

Figure 3 DOX concentrations of the HT groups at mucosa (dark filling), detrusor (light filling), and serosa (clear filling).

Abbreviations: DOX, doxorubicin; DPPG₂, 1.2-dipalmitoyl-sn-glycero-3-phosphodiglycerol; HT, hyperthermia; intraves, intravesical; iv, intravenous; TSL, thermosensitive liposomes.

Table 2 DOX Concentrations per Group and Organ

Group	Heart	Liver	Spleen	Kidney	Lung
iv DPPG2-TSL-DOX (low dose) + HT	0.86 ± 0.06	2.29 ± 0.61	3.90 ± 0.71	4.21 ± 0.64	2.60 ± 0.69
iv DPPG2-TSL-DOX (low dose) + ext. HT	1.12 ± 0.08	2.19 ± 0.20	5.13 ± 0.36	4.59 ± 1.10	6.12 ± 1.76
iv DPPG2-TSL-DOX (low dose) - HT	0.77 ± 0.14	1.73 ± 0.27	4.47 ± 0.45	3.61 ± 0.47	1.40 ± 0.49
iv free DOX (low dose) + HT	1.68 ± 0.17	3.79 ± 0.58	3.63 ± 0.57	10.07 ± 1.54	2.26 ± 0.35
iv DPPG2-TSL-DOX (full dose) + HT	2.85 ± 0.34	10.03 ± 1.52	22.90 ± 5.06	21.03 ± 3.38	18.57 ± 4.06
intraves DOX (full dose) - HT	<0.20*	<0.20*	<0.20*	0.22 ± 0.02	<0.20*
intraves DOX (full dose) + HT	<0.20*	<0.20*	<0.20*	0.24 ± 0.04	<0.20*

Notes: Concentrations are ± standard error of mean in ng/mg; *Represents below limit of quantification.

Abbreviations: DOX, doxorubicin; DPPG₂, 1.2-dipalmitoyl-sn-glycero-3-phosphodiglycerol; HT, hyperthermia; intraves intravesical; iv, intravenous; TSL, thermosensitive liposomes.

Figure 4 DOX plasma concentrations per group. Error bars represent standard error of mean.

Abbreviations: DOX, doxorubicin; DPPG₂, 1.2-dipalmitoyl-sn-glycero-3-phosphodiglycerol; HT, hyperthermia; intraves, intravesical; iv, intravenous; TSL, thermosensitive liposomes.

Figure 5 Fluorescence microscopy of the bladder of (A) intravesical doxorubicin (DOX) without hyperthermia (HT) (full dose); (B) intravenous DPPG₂-thermosensitive liposomes containing DOX (DPPG₂TSL-DOX) with HT (full dose). Red: DOX contained within the tissue; green: cytokeratin filaments of epithelial cells; white: Von-Willebrand-Factor (VWF) within blood vessel walls; and purple: actin filaments in smooth muscle fibres (SMA). White lines mark the transition from mucosa (above the line) to detrusor. The white arrows pointed at red dots show DOX accumulation around the small vessels after DPPG₂-TSL-DOX with HT.