15 research outputs found

    Extracellular vesicles contribute to early cyst development in autosomal dominant polycystic kidney disease by cell-to-cell communication.

    No full text
    Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the formation of fluid-filled cysts within the kidney due to mutations in PKD1 or PKD2. Although the disease remains incompletely understood, one of the factors associated with ADPKD progression is the release of nucleotides (including ATP), which can initiate autocrine or paracrine purinergic signaling by binding to their receptors. Recently, we and others have shown that increased extracellular vesicle (EVs) release from PKD1 knockout cells can stimulate cyst growth through effects on recipient cells. Given that EVs are an important communicator between different nephron segments, we hypothesize that EVs released from PKD1 knockout distal convoluted tubule (DCT) cells can stimulate cyst growth in the downstream collecting duct (CD). Here, we show that administration of EVs derived from Pkd1(-/-) mouse distal convoluted tubule (mDCT15) cells result in a significant increase in extracellular ATP release from Pkd1(-/-) mouse inner medullary collecting duct (iMCD3) cells. In addition, exposure of Pkd1(-/-) iMCD3 cells to EVs derived from Pkd1(-/-) mDCT15 cells led to an increase in the phosphorylation of the serine/threonine-specific protein Akt, suggesting activation of proliferative pathways. Finally, the exposure of iMCD3 Pkd1(-/-) cells to mDCT15 Pkd1(-/-) EVs increased cyst size in Matrigel. These findings indicate that EVs could be involved in intersegmental communication between the distal convoluted tubule and the collecting duct and potentially stimulate cyst growth

    Androgen therapy does not prevent bone loss and arterial calcifications in male rats with CKD

    No full text
    Patients suffering from chronic kidney disease (CKD) often experience bone loss and arterial calcifications. It is unclear if hypogonadism contributes to the development of these complications, and whether androgen therapy might prevent them. Male adult rats were randomized into 4 groups. The first group received standard chow (Control), while three other groups were fed a 0.25% adenine/low vitamin K diet (CKD). Two CKD groups were treated with testosterone (T) or dihydrotestosterone (DHT), whereas the control group and one CKD group received vehicle (VEH). CKD animals had 10-fold higher serum creatinine and more than 15-fold higher PTH-levels compared to controls. Serum T levels were more than 2-fold lower in the CKD-VEH group compared to Control-VEH and CKD-T groups. Seminal vesicle weight was reduced by 50% in CKD-VEH animals, and restored by T and DHT. CKD animals showed a low bone mass phenotype with decreased trabecular bone volume fraction and increased cortical porosity, which was not rescued by androgen treatment. Aortic calcification was much more prominent in CKD animals and not unequivocally prevented by androgens. Messenger RNA expression of the androgen receptor-responsive genes Acta1 and Col1a1 was reduced by CKD and stimulated by androgen treatment in levator ani muscle, but not in bone or aortic tissue. We conclude that adenine-induced CKD results in the development of hypogonadism in male rats. Androgen therapy is effective in restoring serum T levels and androgen-sensitive organ weights, but does not prevent bone loss or arterial calcifications, at least not in the presence of severe hyperparathyroidism

    Testosterone restores body composition, bone mass, and bone strength following early puberty suppression in a mouse model mimicking the clinical strategy in trans boys

    No full text
    Transgender youth increasingly present at pediatric gender services. Some of them receive long-term puberty suppression with gonadotropin-releasing hormone analogues (GnRHa) before starting gender-affirming hormones (GAH). The impact of GnRHa use started in early puberty on bone composition and bone mass accrual is unexplored. It is furthermore unclear whether subsequent GAH fully restore GnRHa effects and whether the timing of GAH introduction matters. To answer these questions, we developed a mouse model mimicking the clinical strategy applied in trans boys. Prepubertal 4-week-old female mice were treated with GnRHa alone or with GnRHa supplemented with testosterone (T) from 6 weeks (early puberty) or 8 weeks (late puberty) onward. Outcomes were analyzed at 16 weeks and compared with untreated mice of both sexes. GnRHa markedly increased total body fat mass, decreased lean body mass, and had a modest negative impact on grip strength. Both early and late T administration shaped body composition to adult male levels, whereas grip strength was restored to female values. GnRHa-treated animals showed lower trabecular bone volume and reduced cortical bone mass and strength. These changes were reversed by T to female levels (cortical bone mass and strength) irrespective of the time of administration or even fully up to adult male control values (trabecular parameters) in case of earlier T start. The lower bone mass in GnRHa-treated mice was associated with increased bone marrow adiposity, also reversed by T. In conclusion, prolonged GnRHa use started in prepubertal female mice modifies body composition toward more fat and less lean mass and impairs bone mass acquisition and strength. Subsequent T administration counteracts GnRHa impact on these parameters, shaping body composition and trabecular parameters to male values while restoring cortical bone architecture and strength up to female but not male control levels. These findings could help guide clinical strategies in transgender care. (c) 2023 American Society for Bone and Mineral Research (ASBMR)

    Um desenho institucional para o novo associativismo An institutional design for the new associativism

    No full text
    Apontam-se elementos de alteração no padrão do associativismo latino-americano e na auto-percepção dos participantes das associações civis. A partir dessa análise, sugere-se um modelo institucional que permitiria potencializar a contribuição desse novo associativismo para a democratização de práticas políticas que se geraram à sombra da debilidade histórica do associativismo civil.<br>Elements of change are pointed out in the pattern of Latin-american associativism and in the self-percetion of the participants in civil associations. Following this analysis an institutional model for this new associativism is sugested, regarding the contribution it could give to the democratization of political practices which developed on the shadow of the historical weakness of civil associativism

    Comparaison des cultures allemande et française et implications marketing

    No full text
    corecore