Recombinant human thyrotropin stimulates thyroid angiogenesis in vivo.

BACKGROUND: Endogenous TSH and rhTSH stimulate thyroid growth by a direct effect on thyrocytes. Our hypothesis was that rhTSH may also stimulate thyroid angiogenesis. STUDY DESIGN: A normal human thyroid tissue sample was grafted into the epigastric area of 14 nude mice. Mice were divided in two groups of 7. The first group (treated mice) received rhTSH stimulation (0.014 UI/mouse/day for 3 weeks), while the second group (control mice) had saline. Histological study with special focus on vascular characteristics was performed by image analysis at day 21 for each graft. VEGF immunostaining score, determined by immunohistochemistry, was defined as the percentage of labeled thyrocytes score, plus an intensity score. RESULTS: Thyroid follicles showed signs of increased colloid re-uptake activity in rhTSH group within a larger surface area than controls (p <0.01). Thyrocytes were taller in the rhTSH group (p <0.01). The diameter of capillary vessels was larger and the microvessels expansion more important in the rhTSH group (p <0.02). Relative capillary area, defined as the ratio between capillary area and follicular area, was also higher in the rhTSH group (p <0.02). VEGF immunostaining score was increased in the rhTSH group (p <0.01). CONCLUSION: rhTSH stimulates angiogenesis and local VEGF expression in normal human thyroid.

Distinct responses of xenografted gliomas to different alkylating agents are related to histology and genetic alterations.

A series of 12 human gliomas was established as xenografts in nude mice and used to evaluate the relationship between histology, genetic parameters, and response to alkylating agents. Eight were high-grade oligodendroglial tumors, and four were glioblastoma. They were characterized for their genetic alterations, including those considered as "early" alterations, namely loss of chromosome 1 +/- loss of chromosome 19q, TP53 mutation, and those considered as "late" alterations, namely loss of chromosome 10, loss of chromosome 9p, EGFR genomic amplification, PTEN mutation, CDKN2A homozygous deletion, and telomerase reactivation. Chemosensitivity of xenografts to four alkylating agents, temozolomide (42 mg/kg, days 1-5, p.o.), 1,3-bis(2-chloroethyl)-1-nitrosourea (5 mg/kg, day 1, i.p.), Ifosfamide (90 mg/kg, days 1-3, i.p.), and carboplatin (66 mg/kg, day 1, i.p.) was tested by administration of drugs to tumor-bearing mice. Although each tumor presented an individual response pattern, glioblastoma had a lower chemosensitivity than oligodendrogliomas, and temozolomide was the most effective drug. Deletion of 1p +/- 19q was associated with higher chemosensitivity, whereas late molecular alterations, particularly EGFR amplification, were associated with chemoresistance. These results suggest that the combined use of histology and molecular markers should eventually be helpful selecting the most appropriate agents for treatment of malignant oligodendrogliomas and astrocytomas.

Efficacy of sulforaphane in eradicating Helicobacter pylori in human gastric xenografts implanted in nude mice.

Sulforaphane, an isothiocyanate abundant in the form of its glucosinolate precursor in broccoli sprouts, has shown in vitro activity against Helicobacter pylori. We evaluated the effect of sulforaphane in vivo against this bacterium by using human gastric xenografts in nude mice. H. pylori was completely eradicated in 8 of the 11 sulforaphane-treated grafts. This result suggests that sulforaphane might be beneficial in the treatment of H. pylori-infected individuals.

Ocular tissue interactions during the development of human fetal neuroretina grafted into nude mice.

To determine the roles of different ocular tissues in the development of the human fetal neuroretina, a study ethically and technically impossible in human subjects, human embryonic and fetal retinas were heterotopically implanted into nude mice. Ninety-five eyeballs were obtained from legally aborted 6- to 7-week-old embryos or 8- to 10-week-old fetuses. Ten isolated neuroretinas with vitreous but without pigment epithelium, 20 half-eyeballs and 70 intact eyeballs, of which 12 had a thick layer of periocular tissue, were microsurgically grafted. Five intact eyeballs were used for reference. Over a period of 1-245 days, all of the grafts were removed for light and electron microscopy observations. All of the isolated neuroretinas had disappeared by the second day after transplantation. Grafts of the posterior section of the eyeball contained only some clusters of pigment epithelium, occasionally covered with undifferentiated neuroretinal cells. Grafts of the retrolental section of the eyeball contained small areas of dysplasic neuroretina with folds and rosettes. Grafts of the 70 intact eyeballs were successful, but only 26 showed normal histological organization of the choriocapillaris, the retinal pigment epithelium and the neuroretina in the posterior part of the posterior chamber. Photoreceptor differentiation was evident in these retinas after approximately 80 days of transplantation and was complete after 166 days. Their anterior part was always dysplasic, with occasional ciliary differentiation. Twenty-three grafted eyeballs had a dysplasic neuroretina with folds, rosettes and necrotized areas. Twenty-one were atrophic, 12 of which were the eyeballs grafted with periocular tissue. These results demonstrate the role of the fetal mesenchyme and pigment epithelium in the rapid revascularization, and subsequent survival and tissue organization, of the neuroretina. The stratified development of the neuroretina required a thin mesenchymal environment for revascularization of the graft by human vasculogenesis or neoangiogenesis and a normal retinal pigment epithelium for normal neuroretinal differentiation. When these conditions were not satisfied, the neuroretina disappeared or was dysplasic, partly necrotized or atrophic. This model might prove useful for a number of therapeutic or clinical studies.

Xenografted human whole embryonic and fetal entoblastic organs develop and become functional adult-like micro-organs.

BACKGROUND AND AIMS: The aim of this study was to study the morphological and functional development in vivo of whole human embryonic and fetal stomachs, intestines, tracheas, and lungs, which would otherwise be ethically and technically impossible to perform in utero, by microsurgically grafting these organs into nude mice. MATERIALS AND METHODS: Five hundred fifty-seven human organs obtained from legally aborted embryos and fetuses of 6-10 weeks were microsurgically grafted into nude mice for 1 to 273 days. Following different grafting times, biopsies were taken for optical and electron microscopy, in situ hybridization, and cellular kinetics studies. A catheter was introduced into the human organs in order to collect and analyze secretions. RESULTS: All of the grafts took successfully. Macroscopic growth was fast during the first 6 to 10 weeks, following which organ size was stable. In situ hybridization studies detected only a minute level of mouse mesenchymal chimerism in the grafts. The different epithelial cells differentiated, became of adult type, and remained normal during the remainder of the grafting periods. The pH of gastric juice from stomachs grafted for 10 to over 90 days dropped from 8.0 +/- 0.1 to 1.58 +/- 0.29 over this time period (P < 0.001), intrinsic factor levels were stable, and pepsin ranged from 6.8 +/- 7.8 to 134 +/- 51 units (P < 0.001). CONCLUSIONS: These results demonstrate that the development of entoblastic organs from human embryos and fetuses microsurgically grafted into nude mice is similar to that occurring in utero. As such, this method provides a model for the analysis of whole human organs in development and later normal adult-like micro-organs for physiological, therapeutic, and pathological studies.