RESUMEN
OBJECT: The goal of this study was to develop a method of reducing neural xenograft rejection by pretreating the graft with photodynamic therapy (PDT). METHODS: Xenograft cell suspensions were prepared from fetal mouse mesencephalon, after which they were incubated for 30 minutes with various concentrations of a photosensitizer, verteporfin for injection, and light exposure. The xenograft cell suspensions were injected into the dopamine-depleted striata of 40 hemiparkinsonian rats assigned to different treatment groups. Four weeks after transplantation, xenograft function (determined by methamphetamine-induced rotation) and survival (determined by immunohistochemical staining for murine neurons) were compared. Group 1 animals (xenografts pretreated with 25 ng/ml verteporfin) and Group 3 animals (no verteporfin pretreatment, but daily administration of cyclosporin A) had significantly better xenograft survival and function compared with control animals (no pretreatment with verteporfin). Group 2 animals (xenografts pretreated with 250 ng/ml verteporfin) had no significant improvement. CONCLUSIONS: This work demonstrates improved neural xenograft survival and function when using pretransplant PDT of the graft in a rodent model. The potential benefits of this new therapy are its convenience (one pretransplant treatment) and its compatibility with host immunosuppression.
Asunto(s)
Trasplante de Tejido Encefálico , Cuerpo Estriado/trasplante , Rechazo de Injerto/prevención & control , Fotoquimioterapia , Análisis de Varianza , Animales , Cuerpo Estriado/metabolismo , Cuerpo Estriado/patología , Ciclosporina/uso terapéutico , Dopamina/deficiencia , Supervivencia de Injerto , Inmunosupresores/uso terapéutico , Masculino , Ratones , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/cirugía , Fotoquimioterapia/métodos , Fármacos Fotosensibilizantes/uso terapéutico , Porfirinas/uso terapéutico , Ratas , Ratas Wistar , Trasplante Heterólogo , VerteporfinaRESUMEN
The photosensitizer benzoporphyrin-derivative monoacid ring A (BPD-MA, verteporfin), in combination with visible light irradiation, a clinical procedure termed photodynamic therapy (PDT), has immunomodulatory activity in various mouse models. We studied the impact of BPD-MA and light upon DBA/2 mouse splenic dendritic cells (DC), a potent antigen-presenting cell (APC) type. DC treated with nanomolar amounts of BPD-MA and 690 nm wavelength light had a reduced capacity to stimulate the proliferation of alloreactive T cells. Treatment with BPD-MA and light reduced DC levels of major histocompatibility (MHC) Class I and II antigens, intercellular adhesion molecule-1 (ICAM-1, CD54), the costimulatory B7-1 (CD80) and B7-2 (CD86) molecules, leucocyte common antigen CD45, the apoptosis-regulating Fas (CD95) receptor and the integrin CD11c. In contrast, DC expression of leucocyte function-associated-1 (LFA-1, CD11a), Mac-1 (CD11b), integrin beta2 chain (CD18) and the DEC-205 receptor increased, while CD40 levels were relatively unchanged 24 h after the treatment. MHC Class I and ICAM-1 levels decreased to 40% of control levels within 2 h following the photodynamic treatment. In the absence of light, BPD-MA did not affect DC receptor levels. Changes in DC receptor levels produced by BPD-MA and red light were similar to those produced by ultraviolet B light irradiation. The photodynamic treatment of activated splenic B cells, a separate APC class, had little effect upon receptor expression, except that MHC Class II levels were moderately decreased 24 h later. Changes in DC receptor expression may contribute to the immunomodulatory action of PDT.
Asunto(s)
Células Dendríticas/efectos de los fármacos , Células Dendríticas/metabolismo , Fotoquimioterapia , Fármacos Fotosensibilizantes/farmacología , Porfirinas/farmacología , Receptores de Superficie Celular/biosíntesis , Bazo/citología , Animales , Antígenos CD/biosíntesis , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Células Dendríticas/citología , Antígenos de Histocompatibilidad Clase I/biosíntesis , Antígenos de Histocompatibilidad Clase II/biosíntesis , Luz , Prueba de Cultivo Mixto de Linfocitos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos DBA , Rayos UltravioletaRESUMEN
BACKGROUND: The ability to prolong graft survival, in some cases by depleting donor antigen-presenting cells (APCs), and the subsequent demonstration that lymphocytes stimulated by non-APCs become anergic, suggested that graft survival and tolerance induction might be achieved by manipulating donor APCs to render them incompetent. This possibility was tested in histoincompatible murine skin allograft with photodynamic therapy (PDT). METHODS: Skin sections (C57BL/6) were exposed in vitro to low doses of benzoporphyrin derivative monoacid ring A (BPD) (verteporfin) and light (A=690+/-10 nm; low-dose PDT) before implantation on recipients (BALB/c). Furthermore, the effect of the treatment on the surface molecules of donor-derived Langerhans cells (LC) was evaluated by fluorescence-activated cell sorter analysis; the effect of treatment on the LC alloreactivity in the mixed epidermal cell lymphocyte reaction was also evaluated. RESULTS: Pretreating skin to be grafted with low-dose PDT can significantly prolong the survival of allografts from 9.3+/-2.2 (n=42) days (control group) to 16.9+/-1.7 days (n=20; treated group). Moreover, low-dose PDT significantly down-regulated the major histocompatibility complex and costimulatory (B7) molecules (60-90% reduction) on LC, but not LC-specific endocytic receptor (DEC-205), CD45, intercellulr adhesion molecule 1, LC viabilities, and ectophosphatase activity on LC. Additionally, this treatment significantly suppressed the ability of LC to stimulate alloreactive T cells to proliferate. CONCLUSIONS: Since engaging T cell receptors in the absence of costimulation results in suboptimal activation of T cells and ultimately anergy, it appears that the immunomodulatory effects of low-dose PDT associated with extended engraftment may depend upon decreased LC expression of major histocompatibility complex and costimulatory molecules.
Asunto(s)
Supervivencia de Injerto/efectos de los fármacos , Fotoquimioterapia , Fármacos Fotosensibilizantes/farmacología , Porfirinas/farmacología , Trasplante de Piel/fisiología , Piel/efectos de los fármacos , Adenosina Trifosfatasas/metabolismo , Análisis de Varianza , Animales , Relación Dosis-Respuesta a Droga , Femenino , Supervivencia de Injerto/efectos de la radiación , Células de Langerhans/efectos de la radiación , Luz , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Piel/efectos de la radiación , Factores de Tiempo , Trasplante HomólogoRESUMEN
Benzoporphyrin derivative monoacid ring A (BPD), a hydrophobic chlorin-like porphyrin derivative, which fluoresces strongly at 690 nm, may have potential for both oncologic and nononcologic applications in photodynamic therapy (PDT). To study the influence of cellular characteristics on the uptake of BPD, the murine tumor cell line (P815), and in vitro and in vivo concanavalin A (Con A) -stimulated and unstimulated murine splenic lymphocytes were incubated with 2 micrograms/mL BPD at 37 degrees C for 0-60 min. At various times, cells were lysed and the amount of BPD taken up by cells was quantified by fluorescence measurements. The subsets of cells taking up BPD were analyzed using a panel of monoclonal antibodies and the Coulter XL fluorescence-activated cell sorter. Furthermore, Con A-stimulated and unstimulated spleen cells were incubated with 0-50 ng/mliter of BPD for 1 h prior to exposure to red light (7.2 J/cm2). Cell survival 24 h post-PDT was measured by the MTT assay. We found that the rapidly dividing tumor cell line and mitogen-stimulated murine T cells (mainly CD4+/IL-2R+) took up significantly more BPD (5-10-fold) than do unstimulated splenic lymphocytes. Increased BPD uptake correlated with greater photoinactivation when these cells were exposed to light at a wavelength of 690 nm. These findings suggest that activated cells of the immune system may be a target for photoinactivation by BPD.
Asunto(s)
Activación de Linfocitos , Linfocitos/efectos de los fármacos , Fármacos Fotosensibilizantes/farmacología , Porfirinas/farmacología , Bazo/citología , Animales , Médula Ósea/efectos de los fármacos , Células de la Médula Ósea , Citometría de Flujo , Ratones , Mitógenos/farmacología , Fotoquimioterapia , Células Tumorales CultivadasRESUMEN
The effect of human serum components on the photodynamic activity of zinc phthalocyanine (ZnPc) toward Chinese hamster fibroblasts (line V-79) was studied. Photodynamic activities were correlated with cellular uptake of radiolabeled [65Zn]ZnPc, which allowed corrections to be made for the amount of sensitizer present in the cells at the time of irradiation and to express photodynamic efficiencies on a cellular dye concentration basis. All serum components, with the exception of high-density lipoproteins, inhibit uptake of ZnPc by V-79 cells, when compared to incubation of ZnPc with the same cells in serum-free medium. High-density lipoproteins increased ZnPc uptake by 23%, but the photodynamic efficiency corrected for the cellular ZnPc concentration was unaffected. Very low-density lipoprotein and globulins decreased ZnPc cell uptake but likewise did not affect the cellular photodynamic efficiency of the dye. In contrast low-density lipoprotein and albumin, while inhibiting ZnPc cell uptake, increased the cellular photodynamic efficiency of ZnPc, suggesting that these proteins facilitate localization of the dye at cellular targets sensitive to photodynamic damage and vital to cell survival. We conclude from these results that association of ZnPc with serum components can have important, and widely differing, effects on both degree of uptake and cellular distribution of the photosensitizer.