Impact of Renal Pelvic Denervation on Systemic Hemodynamics and Neurohumoral Changes in a Porcine Model

INTRODUCTION

The blood pressure (BP) response to arterial renal denervation (RDN) is variable.

METHODS

This study examined the effectiveness of renal pelvic denervation (RPD) on BP, heart rate (HR), norepinephrine (NE), and histopathology in 42 swine. NE levels were measured immediately, 7, 14, 30, and 90 days after RPD. Intra-arterial BP and HR were measured throughout RPD and after 14 days in 5 swine.

RESULTS

During the procedure, RPD immediately reduced systolic BP (-20.6 ± 18.3 mm Hg), diastolic BP (-6.0 ± 8.3 mm Hg), and HR (-5.4 ± 5.6 bpm), which remained decreased at follow-up. The porcine kidneys had a mean NE reduction of 76% directly post procedure and 60% after 7 days, 64% after 14 days, 57% after 30 days, and 65% after 90 days. Histopathological examination confirmed nerve ablation.

CONCLUSIONS

These preliminary findings suggest that the renal pelvis nerve ablation is an encouraging target for RDN. Clinical trials are required to test the feasibility of RPD in human hypertension.

A novel non-vascular system to treat resistant hypertension

AIMS

To evaluate in a preclinical model the utility of a monopolar electrode catheter delivering radiofrequency (RF) energy placed into the renal pelvis in order to treat resistant hypertension (RH).

METHODS AND RESULTS

Sixteen female domestic swine weighing 60-65 kg underwent renal pelvic denervation via ureteral access. Three animals were euthanised immediately after delivery of RF energy; five animals were allowed to survive for seven days, six animals were allowed to survive for 14 days and two animals were allowed to survive for 30 days. Renal cortical norepinephrine levels were measured in all groups of animals. Histopathology of the treated zone was performed to confirm nerve damage. Renal cortical tissue was harvested for determination of tissue norepinephrine by HPLC. The kidneys were then profusion-fixed and harvested for histopathologic analysis. Mean reduction of norepinephrine levels was 60.4% compared to control. Histopathology confirmed nerve ablation in the treated zone.

CONCLUSIONS

In this small, preclinical study, we introduce a new non-vascular system to treat resistant hypertension. If the current clinical experience confirms efficacy and safety, this approach may be one way to treat patients who cannot be treated with the standard percutaneous arterial devices.

Experimental perinatal transmission of human immunodeficiency virus type 1 by passage of infected T cells

Pediatric AIDS typically follows transmission of human immunodeficiency virus type 1 (HIV-1) from infected mothers to their offspring. The possibility that infected maternal-origin cells serve as a conveyance for mother-to-child HIV-1 transmission was investigated in a rabbit infection model. Administration of HIV-1-infected human T cells to pregnant rabbits was followed by evaluation of offspring, from newborn to 1.5 years of age. HIV-1 was detected in 11 of 19 vaginally delivered offspring born to mothers given infected cells during gestation. Interstitial pneumonias or lymphoid organ lesions, similar to those seen in human pediatric AIDS, occurred in some offspring. Persistence of inoculum cell (HLA)-specific gene sequences in offspring indicated that vertical transmission can be effected by T cell-associated virus. These results along with features of rabbit biology, including primate-type placentation, short gestation, and delivery of litters, suggest that the rabbit model is advantageous for studies of perinatal HIV-1 transmission.

Experimental acute adult T cell leukemia-lymphoma is associated with thymic atrophy in human T cell leukemia virus type I infection

Human T cell leukemia virus type I (HTLV-1) infection may lead to an acutely fatal adult T cell leukemia-lymphoma (ATLL), but HTLV-1-infected people usually remain asymptomatic. Why only certain HTLV-I infections lead to acute ATLL, which is characterized by leukemic infiltration of multiple organs and immune suppression, remains unknown. A readily accessible animal model in which the spectrum of consequences resulting from HTLV-I infection can be observed would greatly aid studies of this retrovirus. New Zealand White rabbits inoculated with either HTLV-1-infected CD25+ T cells or cell-free virus, were serially necropsied at different intervals after death or humane sacrifice. Tissues were preserved at necropsy or cultured in vitro and subsequently prepared for morphologic or molecular examination. Rabbits inoculated with RH/K34, a productively infected rabbit T cell line that contains a monoclonally integrated full-length HTLV-I provirus, developed acute ATLL-like biologically malignant lymphoproliferative disease with lymphocyte infiltration of viscera; lymphomas consisting primarily of monoclonal expansions of RH/K34 manifested a variety of diffuse pleomorphic histologic types. Concurrently, lymphoproliferative disease was associated with onset of thymic atrophy in the presence of rapidly increasing thymic proviral load. In contrast, rabbits given two other HTLV-1 inocula, originally derived (as was RH/K34) using the human T cell line MT-2 as virus source, also became infected but did not develop thymic atrophy or the ATLL-like disease. HTLV-1 infection, thymic atrophy, and leukemic infiltration similar to acute ATLL occurred reproducibly in a New Zealand White rabbit model independent of RH/K34 inoculum and host histocompatibility. Thymic atrophy in RH/K34-inoculated rabbits, but not in rabbits given other similar HTLV-1, was consistent with immunosuppression sufficient to prevent rejection of the inoculum. Although the short, 8-day course of the experimental ATLL precludes its having a molecular pathogenesis identical to the human condition, the systemic consequences of acute ATLL, including its association with thymic atrophy, are closely modeled.

Cutaneous manifestations of human T cell leukemia virus type I infection in an experimental model

Skin diseases ranging from infective dermatitis to cutaneous lymphoma have been associated with human T cell leukemia virus (HTLV) type I. A generalized exfoliative papillated dermatopathy occurred in a rabbit 20 months into a course of chronic HTLV-I infection. Biopsies revealed epidermotropic T cell infiltrates, including Sezary-like cells, that resulted in a pattern mimicking cutaneous T cell lymphoma. HTLV-I was isolated from affected skin, and virus expression was detected in cutaneous cultures. Sezary-like cells also occurred in circulation. Interleukin-2-independent lymphocyte cultures, established from blood exhibiting elevated CD8 T cell levels and CD25 expression, had polyclonal integration of provirus. The findings are similar to those in evolving adult T cell leukemia lymphoma and may represent a prelymphomatous change. The cutaneous lymphoproliferative lesion resulted from HTLV-I infection and further establishes the New Zealand White rabbit inoculated with the RH/K34 cell line as a suitable model for investigation of HTLV-I pathogenesis.

Rabbits transfused with human immunodeficiency virus type 1-infected blood develop immune deficiency with CD4+ lymphocytopenia in the absence of clear evidence for HIV type 1 infection

Rabbits can be infected with human immunodeficiency virus (HIV-1), but no disease signs similar to acquired immunodeficiency syndrome (AIDS) have been reported to date. In our attempt to develop types of HIV-1 more virulent for rabbits, an immunodeficiency characterized by CD4+ lymphocytopenia and opportunistic infection was induced by transfusion from HIV-1-infected rabbits. The original donor was infected for 27 months; initial passage resulted in infection of two rabbits. Transfusions from these two infected rabbits. Transfusions from these two infected rabbits caused immunodeficiency in 12 recipients. One rabbit died at 3 months and a second at 8 months postransfusion with lymphocyte depletion in lymphoid organs; one of these and another of the CD4+ lymphocytopenic rabbits had opportunistic infections. Lentivirus-like particles were detected in thymus and spleen from an affected rabbit. Despite appearance of AIDS-like disease signs, antibodies to HIV-1 probes were detected in rabbits receiving passaged blood. However, RNA transcripts hybridizing with HIV-1 probes were detected in organs of some rabbits, implicating the initial HIV infection in the disease. Transfusion from uninfected donors produced no signs of immunodeficiency, which suggests the involvement of an HIV-related agent. The present data do not allow definitive characterization of the agent(s) involved in the immunodeficiency. Possibilities include activation of a rabbit retrovirus or, alternatively, development of a mutated HIV-1 strain.

Prostatic adenocarcinoma in a cat

Prostatic adenocarcinoma was diagnosed in an 11-year-old neutered cat. Clinical signs of the disease included hematuria and a mass in the caudal portion of the abdomen. Prostatectomy was performed. Doxorubicin was administered IV at a dosage of 30 mg/m2 of body surface, followed by cyclophosphamide (300 mg/m2, IV). After 4 treatments, low urine specific gravity and proteinuria developed, and treatment was discontinued. The cat was euthanatized 10 months after surgery because of recurrence of the neoplasm. Necropsy revealed metastasis to the lungs and pancreas.