Body, metabolic and renal changes following cross-sex estrogen/progestogen therapy in a rodent model simulating its use by transwomen

PURPOSE

The use of sex steroids by trans people has been of paramount importance regarding body changes during gender transition. The objective of this study was to assess the effects of an injectable steroid combination frequently used by transwomen, namely estradiol enanthate with dihydroxyprogesterone acetophenide (E2EN/DHPA), on blood pressure and metabolic outcomes using an animal model.

METHODS

Two-month-old male Wistar rats were orchiectomized or sham-operated and divided into groups: (1) Sham treated with sesame oil vehicle (SG), (2) sham treated with E2EN/DHPA (SP), (3) orchiectomized rats treated with vehicle (OG), and (4) orchiectomized rats treated with E2EN/DHPA (OP), with all groups treated every 10 days for 5 months. We evaluated systolic blood pressure (SBP), body weight (BW), abdominal circumference, nasoanal length (NAL), food and water intake (FI, WI), lipid profile (triglycerides, LDL, and HDL), serum C-reactive protein (CRP), plasma concentrations of urea (URpl) and creatinine (CRpl), 24 h urinary volume (V24 h), sodium and potassium excretion (UNa⁺, UK⁺), and proteinuria.

RESULTS

E2EN/DHPA administration reduced BW (SP 324.5 ± 31.1; OP 291.7 ± 41.3 g) and NAL (SP 24.5 ± 0.4; OP 24.6 ± 1.0 cm), without changing blood pressure, but increased URpl concentration (SP 55.0 ± 4.8; OP 42.5 ± 8.8 mg/dL) and CRpl (SP 0.47 ± 0.05; OP 0.46 ± 0.04 mg/dL), sodium (SP 3.1 ± 0.8; OP 3.3 ± 0.4 µEq/min/kg), potassium (SP 0.91 ± 0.22; OP 0.94 ± 0.22 µEq/min/kg) excretions and urinary volume (SP 15.5 ± 2.1; OP 16.4 ± 2.9 mL/24 h).

CONCLUSION

Cross-sex hormone therapy with E2EN/DHPA significantly modified body characteristics in male rats, producing a feminizing change without altering blood pressure or generating harmful metabolic parameters, but larger translational studies are still needed.

Arthropod fauna on the abaxial and adaxial surfaces of Acacia mangium (Fabaceae) leaves

Acacia mangium (Willd., 1806) (Fabales: Fabaceae) is a fast growing, rustic, pioneer species, with potential to fix nitrogen, and for programs to recover degraded areas. The objective was to evaluate the distribution and the functional diversity of interactions and the K-dominance of arthropod groups on A. mangium saplings. The number of individuals of eleven species of phytophagous insects, three bee species, and fourteen natural enemy species were highest on the adaxial leaf surface of this plant. Abundance, diversity and species richness of phytophagous insects and natural enemies, and abundance and species richness of pollinators were highest on the adaxial A. mangium leaf surface. The distribution of five species of sap-sucking hemipterans and six of protocooperating ants (Hymenoptera), with positive interaction between these groups, and three bee species (Hymenoptera) were aggregated on leaves of A. mangium saplings. Aethalion reticulatum (L.) (Hemiptera: Aethalionidae) and Bemisia sp. (Hemiptera: Aleyrodidae); Brachymyrmex sp. and Camponotus sp. (Hymenoptera: Formicidae); and Trigona spinipes Fabricius (Hymenoptera: Apidae) were the most dominant phytophagous insects, natural enemies, and pollinators, respectively, on A. mangium leaves. Knowledge of preferred leaf surfaces could help integrated pest management programs.

Prenatally programmed hypertension: role of maternal diabetes

Epidemiological and experimental studies have led to the hypothesis of the fetal origin of adult diseases, suggesting that some adult diseases might be determined before birth by altered fetal development. Maternal diabetes subjects the fetus to an adverse environment that has been demonstrated to result in metabolic, cardiovascular and renal impairment in the offspring. The growing amount of obesity in young females in developed and some developing countries should contribute to increasing the incidence of diabetes among pregnant women. In this review, we discuss how renal and extrarenal mechanisms participate in the genesis of hypertension induced by a diabetic status during fetal development.

TLR2 and TLR4 expression after kidney ischemia and reperfusion injury in mice treated with FTY720

Ischemia and reperfusion injury (IR) is an antigen independent inflammatory process that causes tissue damage. After IR, kidneys up-regulate leukocyte adhesion molecules and toll-like receptors (TLRs). Moreover, injured kidneys can also secrete factors (i.e. heat shock protein) which bind to TLRs and trigger intracellular events culminating with the increase in the gene expression of inflammatory cytokines. FTY720 is an immunomodulatory compound and protects at least in part kidneys submitted to IR. The mechanisms associated with FTY720's beneficial effects on kidneys after IR remain elusive. We investigated whether FTY720 administration in mice submitted to kidney IR is associated with modulation of TLR2 and TLR4 expression. C57BL/6 mice submitted to 30min of renal pedicles clamp were evaluated for serum parameters (creatinine, urea and nitric oxide), kidney histology, spleen and kidney infiltrating cells expression of TLR2 and TLR4, resident kidney cells expression of TLR2 and TLR4 and IL-6 protein expression in kidney. FTY720-treated mice presented decrease in serum creatinine, urea and nitric oxide, diminished expression of TLR2 and TLR4 both in spleen and kidney infiltrating cells, and reduced kidney IL-6 protein expression in comparison with IR non-treated mice. However, acute tubular necrosis was present both in IR non-treated and IR+FTY720-treated groups. Also, FTY720 did not prevent TLR2 and TLR4 expression in kidney resident cells. In conclusion, FTY720 can promote kidney function recovery after IR by reducing the inflammatory process. Further studies are needed in order to establish whether TLR2 and TLR4 down regulation should be therapeutically addressed as protective targets of renal function and structure after IR.

Effect of D-alpha-tocopherol on tubular nephron acidification by rats with induced diabetes mellitus

The objective of the present study was to determine if treatment of diabetic rats with D-alpha-tocopherol could prevent the changes in glomerular and tubular function commonly observed in this disease. Sixty male Wistar rats divided into four groups were studied: control (C), control treated with D-alpha-tocopherol (C + T), diabetic (D), and diabetic treated with D-alpha-tocopherol (D + T). Treatment with D-alpha-tocopherol (40 mg/kg every other day, ip) was started three days after diabetes induction with streptozotocin (60 mg/kg, ip). Renal function studies and microperfusion measurements were performed 30 days after diabetes induction and the kidneys were removed for morphometric analyses. Data are reported as means +/- SEM. Glomerular filtration rate increased in D rats but decreased in D + T rats (C: 6.43 +/- 0.21; D: 7.74 +/- 0.45; D + T: 3.86 +/- 0.18 ml min-1 kg-1). Alterations of tubular acidification observed in bicarbonate absorption flux (JHCO3) and in acidification half-time (t/2) in group D were reversed in group D + T (JHCO3, C: 2.30 +/- 0.10; D: 3.28 +/- 0.22; D + T: 1.87 +/- 0.08 nmol cm-2 s-1; t/2, C: 4.75 +/- 0.20; D: 3.52 +/- 0.15; D + T: 5.92 +/- 0.19 s). Glomerular area was significantly increased in D, while D + T rats exhibited values similar to C, suggesting that the vitamin prevented the hypertrophic effect of hyperglycemia (C: 8334.21 +/- 112.05; D: 10,217.55 +/- 100.66; D + T: 8478.21 +/- 119.81 microm(2)). These results suggest that D-alpha-tocopherol is able to protect rats, at least in part, from the harmful effects of diabetes on renal function.

Effects of dietary lipids on renal function of aged rats

Normal aging is accompanied by renal functional and morphological deterioration and dietetic manipulation has been used to delay this age-related decline. We examined the effects of chronic administration of diets containing 5% lipid-enriched diet (LD, w/w) on renal function of rats at different ages. Three types of LD were tested: canola oil, fish oil and butter. Mean systemic tail-cuff blood pressure and glycemia remained within the normal range whatever the age and the diet of the animals. Proteinuria began to rise from the 8th month in the groups ingesting LD, while in the control group it increased significantly (above 10 mg/24 h) only after the 10th month. With age, a significant and progressive decline in glomerular filtration rate (GFR) and renal plasma flow was observed in the LD groups but after 6 months of lipid supplementation, the decline in these parameters was more marked in the butter and fish oil groups. By the 18th month, the lowest GFR level was observed in the group ingesting the butter diet (2.93 +/- 0.22 vs 5.01 +/- 0.21 ml min(-1) kg(-1) in control, P<0.05). Net acid excretion, evaluated in 9- and 18-month-old rats, was stimulated in the fish oil group when compared both to control and to the other two LD groups. These results suggest that even low levels of LD in a chronic nutritional regimen can modify the age-related changes in renal function and that the impact of different types of lipid-supplemented diets on renal function depends on the kind of lipid present in the diet.

Influence of parathyroidectomy and calcium on rat renal function

Parathyroid hormone (PTH) has multiple effects on water and electrolyte transport along the nephron. However, the influences of PTH and calcium on the urinary concentration ability are not fully understood. In this study, clearance and microperfusion studies were performed in thyroparathyroidectomized (TPTX) rats either supplemented (TPTX+Ca(2+)) or not with calcium added to the ingested food as CaCl(2) (1.6 g/100 g). Acid-base data and renal functional parameters were measured in TPTX and TPTX+Ca(2+) rats. Additional studies were performed in the isolated inner medullary collecting tubules of intact and TPTX rats to evaluate the osmotic permeability of this segment in the presence of 10(-6) M PTH added to the bath. In these experiments the possible influence of PTH on antidiuretic hormone induced changes of the osmotic permeability in TPTX and TPTX+Ca(2+) rats was also investigated. In the TPTX+Ca(+) group, the glomerular filtration rate increased significantly when compared to the TPTX group (6.04 +/- 0.42 vs. 4.88 +/- 0.20 ml.min(-1).kg(-1); p < 0.05), but the U/P inulin ratio remained lower than control values (30.8 +/- 1.48 vs. 54.0 +/- 3.5; p < 0.05), which suggests that normal levels of PTH are necessary to maintain the concentrating ability. In a group of TPTX rats, an acute infusion of PTH (0.5 microg.min(-1).kg(-1)) significantly decreased the urinary flow and increased the renal plasma flow, results that agree with the vasomodulator action of this hormone on the renal vasculature. A significant increase in the fractional K(+) excretion observed in the TPTX+Ca(2+) group as compared with both control and TPTX, groups suggests that the excreted load of Ca(2+) may interfere with tubular K(+) handling in the absence of PTH. PTH (10(-6) M) added to the bath of the isolated inner medullary collecting tubules did not change the osmotic permeability, of intact, TPTX, and TPTX+Ca(2+) rats. Furthermore, it did not modify the antidiuretic hormone induced changes in the osmotic permeability. These results suggest that this segment of the nephron is PTH insensitive as far as water and ion transport are concerned.

Investigation of the inhibitory effects of homocysteine and copper on nitric oxide-mediated relaxation of rat isolated aorta

1. Elevated plasma levels of homocysteine (HC) and copper have both been associated with the development of inflammatory vascular diseases, such as atherosclerosis. In this study, the effects of a combination of HC and copper on nitric oxide (NO)-mediated relaxation of isolated rat aortic rings were investigated. 2. Exposure to HC (10-100 microM; 30 min) had no effect on relaxation to acetylcholine (ACh; 0.01-10 microM, n=4). Pre-incubation of aortic rings with a higher concentration of HC for an extended period (1 mM; 180 min) significantly inhibited endothelium-dependent relaxation (n=4), but this inhibition was prevented by the presence of the copper chelator bathocuprione (10 microM, 180 min, n=6). 3. Exposure to HC (100 microM) and copper (10-100 microM; 30 min) caused a copper concentration-dependent inhibition of endothelium-dependent relaxation (n=4). This inhibitory effect was reduced in the presence of either superoxide dismutase (SOD; 100 u ml(-1); n=4) or catalase (100 u ml(-1); n=4), and further reduced by the presence of both enzymes (n=5). 4. HC and copper (100 microM; 30 min) significantly inhibited endothelium-independent relaxation to glyceryl trinitrate (0.01-10 microM; n=8). In contrast, HC (1 mM), alone or in combination with copper (100 microM), did not inhibit relaxation to the endothelium-independent relaxant sodium nitroprusside (0.01-10 microM; n=4). 5. These data indicate that the presence of copper greatly enhances the inhibitory actions of HC on NO-mediated relaxation of isolated aortic rings. The reduction of inhibition by catalase and SOD indicates a possible role for copper-catalyzed generation of superoxide and hydrogen peroxide leading to an increased inactivation or decreased production of endothelium-derived NO.

Interaction of atrial natriuretic factor and angiotensin II in proximal HCO3- reabsorption

Bicarbonate reabsorption was evaluated by the acidification kinetics technique in middle proximal tubule in Munich-Wistar rats. Atrial natriuretic factor (ANF) and angiotensin II (ANG II) were infused into the jugular vein (ANF, 0.5 microgram.min-1.kg-1 after a prime of 10 micrograms/kg; ANG II, 20 ng.min-1.kg-1) or added to luminal or peritubular perfusion fluid (10(-6) M ANF; 10(-12) M ANG II). In the presence of ANF, in each condition, no significant differences in net HCO3- reabsorption or in acidification half time were observed compared with the control group. In the presence of ANG II, a significant increase in HCO3- reabsorption was observed, expressed by a fall in acidification half time from a mean of 4.75 +/- 0.20 (n = 86) to 2.47 +/- 0.18 s (n = 32) in systemically infused rats or to 2.30 +/- 0.15 s (n = 35) in luminally perfused tubules and from 4.57 +/- 0.32 (n = 44) to 2.04 +/- 0.10 s (n = 50) during capillary perfusion. However, when ANG II was systemically infused or perfused in lumen or in peritubular capillaries, addition of ANF to lumen or capillaries by perfusion or systemic infusion abolished the effects observed with ANG II alone. These studies confirm that ANG II stimulates proximal HCO3- reabsorption and show that ANF alone does not affect this process, but impairs the stimulation caused by ANG II.