Multiple variation of right renal and gonadal vascularization: report of two cases / Variação múltipla da vascularização renal e gonadal direita: relato de dois casos

Abstract We present two cases of multiple anatomical variations of the renal and gonadal vessels. The first case presented duplication of the renal vein and the presence of an accessory renal artery. However, the most interesting fact, in this case, was that the right gonadal vein emptied into the inferior right renal vein instead of ending in the inferior vena cava as would typically be the case. In the second case, we also found an accessory renal artery and the right gonadal vein emptied at the exact junction between the right renal vein and the inferior vena cava. Clinicians and surgeons should be familiar with anatomical variations to provide an accurate diagnosis during preoperative studies and to avoid surprises in abdominal surgical procedures.

Resumo Este estudo apresenta dois casos de variação anatômica múltipla de vasos renais e gonadais. O primeiro caso apresentou uma duplicação da veia renal e a presença de uma artéria renal acessória. Porém, o fato mais interessante nesse caso foi a veia gonadal direita desembocar na veia renal direita inferior em vez de terminar na veia cava inferior, como seria o normal. No segundo caso, além de também encontrarmos uma artéria renal acessória, a veia gonadal direita desembocava no exato ponto de junção entre a veia renal direita e a veia cava inferior. Clínicos e cirurgiões devem estar familiarizados com a presença de possíveis variações dos vasos renais e gonadais, sendo um conhecimento imprescindível para obter um diagnóstico mais preciso e para evitar surpresas em procedimentos cirúrgicos abdominais.

Hyperkyphosis is not dependent on bone mass and quality in the mouse model of Marfan syndrome.

Marfan syndrome (MFS) is an autosomal dominant disease affecting cardiovascular, ocular and skeletal systems. It is caused by mutations in the fibrillin-1 (FBN1) gene, leading to structural defects of connective tissue and increased activation of TGF-ß. Angiotensin II (ang-II) is involved in TGF-ß activity and in bone mass regulation. Inhibition of TGF-ß signaling by blockage of the ang-II receptor 1 (AT1R) via losartan administration leads to improvement of cardiovascular and pulmonary phenotypes, but has no effect on skeletal phenotype in the haploinsufficient mouse model of MFS mgR, suggesting a distinct mechanism of pathogenesis in the skeletal system. Here we characterized the skeletal phenotypes of the dominant-negative model for MFS mgΔlpn and tested the effect of inhibition of ang-II signaling in improving those phenotypes. As previously shown, heterozygous mice present hyperkyphosis, however we now show that only males also present osteopenia. Inhibition of ang-II production by ramipril minimized the kyphotic deformity, but had no effect on bone microstructure in male mutant animals. Histological analysis revealed increased thickness of the anterior longitudinal ligament (ALL) of the spine in mutant animals (25.8 ± 6.3 vs. 29.7 ± 7.7 µm), coupled with a reduction in type I (164.1 ± 8.7 vs. 139.0 ± 4.4) and increase in type III (86.5 ± 10.2 vs. 140.4 ± 5.6) collagen in the extracellular matrix of this ligament. In addition, we identified in the MFS mice alterations in the erector spinae muscles which presented thinner muscle fibers (1035.0 ± 420.6 vs. 655.6 ± 239.5 µm2) surrounded by increased area of connective tissue (58.17 ± 6.52 vs. 105.0 ± 44.54 µm2). Interestingly, these phenotypes were ameliorated by ramipril treatment. Our results reveal a sex-dependency of bone phenotype in MFS, where females do not present alterations in bone microstructure. More importantly, they indicate that hyperkyphosis is not a result of osteopenia in the MFS mouse model, and suggest that incompetent spine ligaments and muscles are responsible for the development of that phenotype.

The mgΔlpn mouse model for Marfan syndrome recapitulates the ocular phenotypes of the disease.

PURPOSE: Fibrillin-1 and -2 are major components of tissue microfibrils that compose the ciliary zonule and cornea. While mutations in human fibrillin-1 lead to ectopia lentis, a major manifestation of Marfan syndrome (MFS), in mice fibrillin-2 can compensate for reduced/lack of fibrillin-1 and maintain the integrity of ocular structures. Here we examine the consequences of a heterozygous dominant-negative mutation in the Fbn1 gene in the ocular system of the mgΔlpn mouse model for MFS. METHODS: Eyes from mgΔlpn and wild-type mice at 3 and 6 months of age were analyzed by histology. The ciliary zonule was analyzed by scanning electron microscopy (SEM) and immunofluorescence. RESULTS: Mutant mice presented a significantly larger distance of the ciliary body to the lens at 3 and 6 months of age when compared to wild-type, and ectopia lentis. Immunofluorescence and SEM corroborated those findings in MFS mice, revealing a disorganized mesh of microfibrils on the floor of the ciliary body. Moreover, mutant mice also had a larger volume of the anterior chamber, possibly due to excess aqueous humor. Finally, losartan treatment had limited efficacy in improving ocular phenotypes. CONCLUSIONS: In contrast with null or hypomorphic mutations, expression of a dominant-negative form of fibrillin-1 leads to disruption of microfibrils in the zonule of mice. This in turn causes lens dislocation and enlargement of the anterior chamber. Therefore, heterozygous mgΔlpn mice recapitulate the major ocular phenotypes of MFS and can be instrumental in understanding the development of the disease.