bacteriochlorophylls and Disease-Models--Animal

Τhe morphology, physiology and immunology, of solid tumors exhibit spatial heterogeneity which complicates our understanding of cancer progression and therapy response. Understanding spatial heterogeneity necessitates high resolution in vivo imaging of anatomical and pathophysiological tumor information. We introduce Rhodobacter as bacterial reporter for multispectral optoacoustic (photoacoustic) tomography (MSOT). We show that endogenous bacteriochlorophyll a in Rhodobacter gives rise to strong optoacoustic signals >800 nm away from interfering endogenous absorbers. Importantly, our results suggest that changes in the spectral signature of Rhodobacter which depend on macrophage activity inside the tumor can be used to reveal heterogeneity of the tumor microenvironment. Employing non-invasive high resolution MSOT in longitudinal studies we show spatiotemporal changes of Rhodobacter spectral profiles in mice bearing 4T1 and CT26.WT tumor models. Accessibility of Rhodobacter to genetic modification and thus to sensory and therapeutic functions suggests potential for a theranostic platform organism.

Topics: Animals; Bacteriochlorophyll A; Biosensing Techniques; Cell Line, Tumor; Disease Models, Animal; Humans; Longitudinal Studies; Macrophages; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasms; Photoacoustic Techniques; Rhodobacter; Theranostic Nanomedicine; Tomography, X-Ray Computed; Tumor Microenvironment

Vascular targeted photodynamic therapy with WST11 (TOOKAD® Soluble) is in phase III clinical trials of an interstitial transperineal approach for focal therapy of prostate cancer. We investigated the safety and efficacy of the endourethral route in the context of benign prostatic hyperplasia in the dog model.. An optical laser fiber was positioned in the prostatic urethra of 34 dogs, including 4 controls. It was connected to a 753 nm diode laser at 200 mW/cm fluence, delivering 200 to 300 J. WST11 (5 to 15 mg/kg) was infused intravenously in 2 modes, including continuous, starting 5 to 15 minutes before and during illumination, or a bolus 5 to 10 minutes before illumination. Prostate ultrasound, cystourethrogram, urodynamics and histopathology were performed. Followup was 1 week to 1 year.. Endourethral WST11 vascular targeted photodynamic therapy was uneventful in all except 1 dog, which experienced urinary retention but reached the 1-week end point. All prostates except those in controls showed hemorrhagic lesions. They consisted of 2 levels of concentric alterations, including periurethral necrosis with endothelial layer destruction and adjacent inflammation/atrophy with normal blood vessels. Prostatic urethral width increased as early as 6 weeks after treatment, while prostatic volume decreased, reaching 25% by 18 to 26 weeks. A parallel decrease in urethral pressure at 6 weeks lasted up to 1 year.. We confirmed the vascular effect of endourethral WST11 vascular targeted photodynamic therapy. To our knowledge we report for the first time that the resulting periurethral necrosis led to significant, sustained widening of the prostatic urethra, accompanied by long-term improvement in urodynamic parameters. These findings support future clinical applications of this minimally invasive approach to benign prostatic hyperplasia.

Topics: Animals; Bacteriochlorophylls; Disease Models, Animal; Dogs; Drug Evaluation, Preclinical; Endoscopy; Male; Photochemotherapy; Photosensitizing Agents; Prostate; Prostatic Hyperplasia

Antiangiogenic and anti-vascular therapies present intriguing alternatives to cancer therapy. However, despite promising preclinical results and significant delays in tumor progression, none have demonstrated long-term curative features to date. Here, we show that a single treatment session of Tookad-based vascular targeted photodynamic therapy (VTP) promotes permanent arrest of tumor blood supply by rapid occlusion of the tumor feeding arteries (FA) and draining veins (DV), leading to tumor necrosis and eradication within 24-48 h.. A mouse earlobe MADB106 tumor model was subjected to Tookad-VTP and monitored by three complementary, non-invasive online imaging techniques: Fluorescent intravital microscopy, Dynamic Light Scattering Imaging and photosensitized MRI. Tookad-VTP led to prompt tumor FA vasodilatation (a mean volume increase of 70%) with a transient increase (60%) in blood-flow rate. Rapid vasoconstriction, simultaneous blood clotting, vessel permeabilization and a sharp decline in the flow rates then followed, culminating in FA occlusion at 63.2 sec+/-1.5SEM. This blockage was deemed irreversible after 10 minutes of VTP treatment. A decrease in DV blood flow was demonstrated, with a slight lag from FA response, accompanied by frequent changes in flow direction before reaching a complete standstill. In contrast, neighboring, healthy tissue vessels of similar sizes remained intact and functional after Tookad-VTP.. Tookad-VTP selectively targets the tumor feeding and draining vessels. To the best of our knowledge, this is the first mono-therapeutic modality that primarily aims at the larger tumor vessels and leads to high cure rates, both in the preclinical and clinical arenas.

Topics: Animals; Arteries; Bacteriochlorophylls; Blood Coagulation; Blood Flow Velocity; Disease Models, Animal; Ear; Mice; Necrosis; Neoplasms; Neovascularization, Pathologic; Permeability; Photochemotherapy; Treatment Outcome; Vasoconstriction; Veins

Up to date several approaches have been undertaken to achieve an 'easy-to-handle' animal model of choroidal neovascularizations (CNVs) in rabbits; however, so far in none of the studies could healthy retinal tissue be maintained, which is mandatory to further investigate the effects of photodynamic therapy (PDT) or anti-vascular-endothelial-growth-factor treatments. It was our aim to reevaluate and verify the method of inducing experimental CNVs in rabbits using subretinally injected linoleic acid hydroperoxide (LHP) as proposed by Tamai et al. and to use it for experimental PDT.. In 33 eyes of Chinchilla breed rabbits LHP of two different concentrations (25 and 100 microg/50 microl) was injected into the subretinal space via a transvitreal approach under guidance of an operation microscope. Ophthalmoscopic and angiographic examinations were performed on days 3, 7, 14 and 28 after surgery. Preliminary PDT with different experimental parameter sets was performed in 3 eyes using the new photosensitizer Tookad.. Using LHP in the higher concentration, an angiographically determined CNV induction was observed in 27% of all injection sites (n = 34) on days 14 and 28 revealing early well-demarcated and progressive leakage. No CNV was detected at the lower LHP concentration (60 injection sites). Subretinal CNV was verified histologically revealing vessel formation above the retinal pigment epithelium level. Herein, a significant damage to the outer retinal layers was always observed; however, the general structure of the choriocapillary layer was maintained. Tookad PDT was clinically able to completely stop leakage in 1 case and reduce leakage in 2 cases. Histologically the choriocapillary layer was occluded.. Subretinal injection of LHP induces angiographically well-demarcated classic CNVs in rabbits; however, the CNV rate was low, and histology revealed severe damage of the outer retinal layers but not of the choriocapillary layer, which is important for studying PDT interactions. Preliminary experimental PDT could clinically stop or reduce leakage from angiographic CNV. Due to the small CNV rate and the significant collateral retinal tissue damage, this model seems to be only of partial suitability for investigating new treatment modalities in CNV.

Topics: Animals; Bacteriochlorophylls; Choroidal Neovascularization; Disease Models, Animal; Fluorescein Angiography; Injections; Linoleic Acids; Lipid Peroxides; Macular Degeneration; Photochemotherapy; Photosensitizing Agents; Rabbits; Retina

To evaluate the photodynamic potential of a new hydrosoluble photosensitizer (WST-11, Stakel; Steba Biotech, Toussus-Le-Noble, France), for use in occlusion of normal choroidal vessels in the rabbit eye and CNV (choroidal neovascularization) in the rat eye.. Occlusive and nonocclusive parameters of Stakel and verteporfin photodynamic therapy (PDT) were investigated in pigmented rabbits. Eyes were followed by fluorescein angiography (FA) and histology at various intervals after PDT.. When occlusive parameters (fluence of 50 J/cm(2), 5 mg/kg drug dose and DLI [distance to light illumination] of 1 minute) were used, Stakel PDT was efficient immediately after treatment without associated structural damage of the RPE and retina overlying the treated choroid in the rabbit eye. Two days later, total occlusion of the choriocapillaries was seen in 100% of the treated eyes, along with accompanying histologic structural changes in the overlying retina. When the occlusive parameters (fluence, 100 J/cm2; drug dose, 12 mg/m2; and DLI, 5 minutes) of verteporfin PDT were used, occlusion of the choriocapillaries was observed in 89% of the treated eyes. Histology performed immediately after treatment demonstrated structural damage of the overlying retina and RPE layer. Weaker, nonocclusive Stakel PDT parameters (25 J/cm2, 5 mg/kg, and DLI of 10 minutes) did not induce choriocapillary occlusion or retinal lesions on FA or histology. Weaker, nonocclusive verteporfin PDT parameters (10 J/cm2, 0.2 mg/kg, and DLI of 5 minutes) did not induce choriocapillary occlusion. However, histology of these eyes showed the presence of damage in the retinal and choroidal tissues. Moreover, preliminary results indicate that selective CNV occlusion can be achieved with Stakel PDT in the rat eye.. Unlike verteporfin PDT, Stakel PDT does not cause direct damage to the RPE cell layer or retina. These observations indicate that Stakel PDT may have a high potential for beneficial therapeutic outcomes in treatment of AMD.

Topics: Animals; Bacteriochlorophylls; Choroid; Choroidal Neovascularization; Disease Models, Animal; Drug Evaluation, Preclinical; Fluorescein Angiography; Laser Coagulation; Photochemotherapy; Photosensitizing Agents; Pigment Epithelium of Eye; Porphyrins; Rabbits; Rats; Rats, Inbred BN; Retina; Verteporfin

Antivascular photodynamic therapy (PDT) of tumors with palladium-bacteriopheophorbide (TOOKAD) relies on in situ photosensitization of the circulating drug by local generation of cytotoxic reactive oxygen species, which leads to rapid vascular occlusion, stasis, necrosis and tumor eradication. Intravascular production of reactive oxygen species is associated with photoconsumption of O(2) and consequent evolution of paramagnetic deoxyhemoglobin. In this study we evaluate the use of blood oxygenation level-dependent (BOLD) contrast magnetic resonance imaging (MRI) for real-time monitoring of PDT efficacy. Using a solid tumor model, we show that TOOKAD-PDT generates appreciable attenuation (25-40%) of the magnetic resonance signal, solely at the illuminated tumor site. This phenomenon is independent of, though augmented by, ensuing changes in blood flow. These results were validated by immunohistochemistry and intravital microscopy. The concept of photosensitized BOLD-contrast MRI may have intraoperative applications in interactive guidance and monitoring of antivascular cancer therapy, PDT treatment of macular degeneration, interventional cardiology and possibly other biomedical disciplines.

Topics: Animals; Bacteriochlorophylls; Contrast Media; Disease Models, Animal; Hemoglobins; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Melanoma; Mice; Photochemotherapy; Photosensitizing Agents; Reactive Oxygen Species; Skin Neoplasms