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A sex-specific role for androgens in angiogenesis.

Sieveking DP, Lim P, Chow RW, Dunn LL, Bao S, McGrath KC, Heather AK, Handelsman DJ, Celermajer DS, Ng MK - J. Exp. Med. (2010)

Bottom Line: Androgen receptor (AR) antagonism or gene knockdown abrogated these effects in male ECs.In vivo, castration dramatically reduced neovascularization of Matrigel plugs.Androgen treatment fully reversed this effect in male mice but had no effect in female mice.

View Article: PubMed Central - HTML - PubMed

Affiliation: Heart Research Institute, Sydney 2042, Australia. sievekingd@hri.org.au

ABSTRACT
Mounting evidence suggests that in men, serum levels of testosterone are negatively correlated to cardiovascular and all-cause mortality. We studied the role of androgens in angiogenesis, a process critical in cardiovascular repair/regeneration, in males and females. Androgen exposure augmented key angiogenic events in vitro. Strikingly, this occurred in male but not female endothelial cells (ECs). Androgen receptor (AR) antagonism or gene knockdown abrogated these effects in male ECs. Overexpression of AR in female ECs conferred androgen sensitivity with respect to angiogenesis. In vivo, castration dramatically reduced neovascularization of Matrigel plugs. Androgen treatment fully reversed this effect in male mice but had no effect in female mice. Furthermore, orchidectomy impaired blood-flow recovery from hindlimb ischemia, a finding rescued by androgen treatment. Our findings suggest that endogenous androgens modulate angiogenesis in a sex-dependent manner, with implications for the role of androgen replacement in men.

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Endogenous androgens modulate ischemia-induced angiogenesis. (A) LDPI. Limb perfusion ratio (ischemic/nonischemic) is presented with representative images (n = 8/group; combined data from four independent experiments are shown). Differences between groups were assessed by two-way ANOVA with Bonferroni correction (brackets at right). *, P < 0.05; and **, P < 0.01 for comparisons between orchidectomized and orchidectomized + DHT mice at individual time points. (B) Representative images of neovascularization of ischemic hindlimbs at day 7. Capillary density was measured in 8-µm frozen sections of the adductor muscles via immunohistochemical staining for vWF (arrows). Bars, 100 µm. (C) Capillary density expressed as the number of capillaries per myofiber (eosin) and (D) mean vessel diameter (n = 6/group; combined data from three independent experiments are shown). (E–G) Mechanisms of androgenic modulation of angiogenesis in hindlimb ischemia at day 3. Quantitative RT-PCR for the expression of the angiogenesis- and ischemia-related genes (E) HIF-1α, (F) SDF-1α, and (G) KDR (n = 6/group; combined data from three independent experiments are shown). *, P < 0.05; **, P < 0.01; and ***, P < 0.001 versus control using ANOVA. All data are expressed as means ± SEM.
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fig5: Endogenous androgens modulate ischemia-induced angiogenesis. (A) LDPI. Limb perfusion ratio (ischemic/nonischemic) is presented with representative images (n = 8/group; combined data from four independent experiments are shown). Differences between groups were assessed by two-way ANOVA with Bonferroni correction (brackets at right). *, P < 0.05; and **, P < 0.01 for comparisons between orchidectomized and orchidectomized + DHT mice at individual time points. (B) Representative images of neovascularization of ischemic hindlimbs at day 7. Capillary density was measured in 8-µm frozen sections of the adductor muscles via immunohistochemical staining for vWF (arrows). Bars, 100 µm. (C) Capillary density expressed as the number of capillaries per myofiber (eosin) and (D) mean vessel diameter (n = 6/group; combined data from three independent experiments are shown). (E–G) Mechanisms of androgenic modulation of angiogenesis in hindlimb ischemia at day 3. Quantitative RT-PCR for the expression of the angiogenesis- and ischemia-related genes (E) HIF-1α, (F) SDF-1α, and (G) KDR (n = 6/group; combined data from three independent experiments are shown). *, P < 0.05; **, P < 0.01; and ***, P < 0.001 versus control using ANOVA. All data are expressed as means ± SEM.

Mentions: Hypoxia is one of the most potent angiogenic stimuli (Ceradini and Gurtner, 2005). To investigate the role of androgens in ischemia-induced angiogenesis, we used a mouse model of hindlimb ischemia involving the unilateral ligation and removal of the femoral artery (Couffinhal et al., 1998). Male mice were randomized to orchidectomy with or without DHT treatment or a sham orchidectomy. Laser Doppler perfusion imaging demonstrated that orchidectomy markedly inhibited the rate of recovery from hindlimb ischemia (laser Doppler perfusion index [LDPI] ischemic/nonischemic ratio after 11 d: control, 0.54 ± 0.04; castrate, 0.39 ± 0.04; P < 0.05; Fig. 5 A). In functional assessments of the ischemic hindlimbs, orchidectomized animals also displayed impaired recovery in foot movement and ischemic damage (Fig. S3). Interestingly, DHT not only rescued the orchidectomy-induced impairment of blood flow recovery but also enhanced recovery from ischemia, with improvements in flow detectable as early as day 3 and significant by day 5 after ischemia (LDPI at day 5 after ischemia: control, 0.28 ± 0.04; orchidectomized + DHT, 0.4 ± 0.05; P < 0.05 vs. orchidectomized mice; Fig. 5 A). These findings were also borne out in the functional assessments of recovery (Fig. S3). The serial changes in perfusion observed after femoral artery ligation have previously been shown to correlate with changes in vessel density as determined by histological analysis (Couffinhal et al., 1998). As early as day 7, immunohistochemical staining of the adductor muscles of the ischemic hindlimbs revealed that capillary density was impaired in orchidectomized mice and augmented in DHT-treated orchidectomized mice (0.17 ± 0.01 and 0.27 ± 0.01 vs. 0.22 ± 0.01 capillaries/myofiber for orchidectomized mice, orchidectomized + DHT mice, and controls, respectively; P < 0.001 using ANOVA; Fig. 5, B and C), consistent with the findings observed for limb perfusion. Mean vessel diameter was also significantly smaller in orchidectomized mice (P < 0.001; Fig. 5 D). Interestingly, mean vessel diameter was also smaller in orchidectomized mice receiving DHT, but DHT treatment appeared to mitigate the effects of castration. These data suggest that, in the context of ischemia, endogenous androgens influence the rate and extent of ischemia-induced angiogenesis and play a role in arteriogenesis.


A sex-specific role for androgens in angiogenesis.

Sieveking DP, Lim P, Chow RW, Dunn LL, Bao S, McGrath KC, Heather AK, Handelsman DJ, Celermajer DS, Ng MK - J. Exp. Med. (2010)

Endogenous androgens modulate ischemia-induced angiogenesis. (A) LDPI. Limb perfusion ratio (ischemic/nonischemic) is presented with representative images (n = 8/group; combined data from four independent experiments are shown). Differences between groups were assessed by two-way ANOVA with Bonferroni correction (brackets at right). *, P < 0.05; and **, P < 0.01 for comparisons between orchidectomized and orchidectomized + DHT mice at individual time points. (B) Representative images of neovascularization of ischemic hindlimbs at day 7. Capillary density was measured in 8-µm frozen sections of the adductor muscles via immunohistochemical staining for vWF (arrows). Bars, 100 µm. (C) Capillary density expressed as the number of capillaries per myofiber (eosin) and (D) mean vessel diameter (n = 6/group; combined data from three independent experiments are shown). (E–G) Mechanisms of androgenic modulation of angiogenesis in hindlimb ischemia at day 3. Quantitative RT-PCR for the expression of the angiogenesis- and ischemia-related genes (E) HIF-1α, (F) SDF-1α, and (G) KDR (n = 6/group; combined data from three independent experiments are shown). *, P < 0.05; **, P < 0.01; and ***, P < 0.001 versus control using ANOVA. All data are expressed as means ± SEM.
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fig5: Endogenous androgens modulate ischemia-induced angiogenesis. (A) LDPI. Limb perfusion ratio (ischemic/nonischemic) is presented with representative images (n = 8/group; combined data from four independent experiments are shown). Differences between groups were assessed by two-way ANOVA with Bonferroni correction (brackets at right). *, P < 0.05; and **, P < 0.01 for comparisons between orchidectomized and orchidectomized + DHT mice at individual time points. (B) Representative images of neovascularization of ischemic hindlimbs at day 7. Capillary density was measured in 8-µm frozen sections of the adductor muscles via immunohistochemical staining for vWF (arrows). Bars, 100 µm. (C) Capillary density expressed as the number of capillaries per myofiber (eosin) and (D) mean vessel diameter (n = 6/group; combined data from three independent experiments are shown). (E–G) Mechanisms of androgenic modulation of angiogenesis in hindlimb ischemia at day 3. Quantitative RT-PCR for the expression of the angiogenesis- and ischemia-related genes (E) HIF-1α, (F) SDF-1α, and (G) KDR (n = 6/group; combined data from three independent experiments are shown). *, P < 0.05; **, P < 0.01; and ***, P < 0.001 versus control using ANOVA. All data are expressed as means ± SEM.
Mentions: Hypoxia is one of the most potent angiogenic stimuli (Ceradini and Gurtner, 2005). To investigate the role of androgens in ischemia-induced angiogenesis, we used a mouse model of hindlimb ischemia involving the unilateral ligation and removal of the femoral artery (Couffinhal et al., 1998). Male mice were randomized to orchidectomy with or without DHT treatment or a sham orchidectomy. Laser Doppler perfusion imaging demonstrated that orchidectomy markedly inhibited the rate of recovery from hindlimb ischemia (laser Doppler perfusion index [LDPI] ischemic/nonischemic ratio after 11 d: control, 0.54 ± 0.04; castrate, 0.39 ± 0.04; P < 0.05; Fig. 5 A). In functional assessments of the ischemic hindlimbs, orchidectomized animals also displayed impaired recovery in foot movement and ischemic damage (Fig. S3). Interestingly, DHT not only rescued the orchidectomy-induced impairment of blood flow recovery but also enhanced recovery from ischemia, with improvements in flow detectable as early as day 3 and significant by day 5 after ischemia (LDPI at day 5 after ischemia: control, 0.28 ± 0.04; orchidectomized + DHT, 0.4 ± 0.05; P < 0.05 vs. orchidectomized mice; Fig. 5 A). These findings were also borne out in the functional assessments of recovery (Fig. S3). The serial changes in perfusion observed after femoral artery ligation have previously been shown to correlate with changes in vessel density as determined by histological analysis (Couffinhal et al., 1998). As early as day 7, immunohistochemical staining of the adductor muscles of the ischemic hindlimbs revealed that capillary density was impaired in orchidectomized mice and augmented in DHT-treated orchidectomized mice (0.17 ± 0.01 and 0.27 ± 0.01 vs. 0.22 ± 0.01 capillaries/myofiber for orchidectomized mice, orchidectomized + DHT mice, and controls, respectively; P < 0.001 using ANOVA; Fig. 5, B and C), consistent with the findings observed for limb perfusion. Mean vessel diameter was also significantly smaller in orchidectomized mice (P < 0.001; Fig. 5 D). Interestingly, mean vessel diameter was also smaller in orchidectomized mice receiving DHT, but DHT treatment appeared to mitigate the effects of castration. These data suggest that, in the context of ischemia, endogenous androgens influence the rate and extent of ischemia-induced angiogenesis and play a role in arteriogenesis.

Bottom Line: Androgen receptor (AR) antagonism or gene knockdown abrogated these effects in male ECs.In vivo, castration dramatically reduced neovascularization of Matrigel plugs.Androgen treatment fully reversed this effect in male mice but had no effect in female mice.

View Article: PubMed Central - HTML - PubMed

Affiliation: Heart Research Institute, Sydney 2042, Australia. sievekingd@hri.org.au

ABSTRACT
Mounting evidence suggests that in men, serum levels of testosterone are negatively correlated to cardiovascular and all-cause mortality. We studied the role of androgens in angiogenesis, a process critical in cardiovascular repair/regeneration, in males and females. Androgen exposure augmented key angiogenic events in vitro. Strikingly, this occurred in male but not female endothelial cells (ECs). Androgen receptor (AR) antagonism or gene knockdown abrogated these effects in male ECs. Overexpression of AR in female ECs conferred androgen sensitivity with respect to angiogenesis. In vivo, castration dramatically reduced neovascularization of Matrigel plugs. Androgen treatment fully reversed this effect in male mice but had no effect in female mice. Furthermore, orchidectomy impaired blood-flow recovery from hindlimb ischemia, a finding rescued by androgen treatment. Our findings suggest that endogenous androgens modulate angiogenesis in a sex-dependent manner, with implications for the role of androgen replacement in men.

Show MeSH
Related in: MedlinePlus