Is There a Role for Levo-Thyroxine for the Treatment of Arterial Erectile Dysfunction? The Clinical Relevance of the Mean Platelet Volume

Abstract

Background: Arterial erectile dysfunction (ED) is an early sign of vascular damage. Rare evidence has been published so far as to whether subclinical hypothyroidism (SCH) affects arterial erectile function. Therefore, the objective of this study was to fill this gap.

Methods: Patients with arterial ED and SCH were consecutive enrolled and randomly divided into Group A (n = 20) and Group B (n = 20). Group A was treated with levo-thyroxine (LT4) at the dose of 1 µg/kg/day for six months, whereas patients of the group B did not receive any treatment. Thyroid stimulating hormone (TSH), free-thyroxine (FT4), peak systolic velocity (PSV), International Index of Erectile Function 5-item version (IIEF-5) score, mean platelet volume (MPV), and total cholesterol were evaluated at enrollment (T0) and after six months (T1). Patients without hypertension, diabetes mellitus, dyslipidemia, not on drugs, and with normal total testosterone (TT) values were included in this study.

Results: Group A and B did not differ for age (61.2 ± 4.8 vs. 60.3 ± 5.6 years), body-mass index (28.7 ± 2.5 vs. 28.3 ± 2.6 Kg/m²), and serum TT levels (481.2 ± 54.0 vs. 492.1 ± 59.7 ng/dL). At T0, serum TSH levels (6.5 ± 1.2 vs. 6.0 ± 1.0 µIU/mL), FT4 (8.8 ± 0.6 vs. 8.8 ± 0.6 pmol/L), PSV (26.5 ± 1.4 vs. 25.8 ± 2.1 cm/s), IIEF-5 score (8.2 ± 1.7 vs. 9.0±1.7), and total cholesterol (167.8 ± 21.7 vs. 171.6 ± 21.3 mg/dL) did not significantly differ in patients of Group A vs. those of Group B. MPV was significantly higher in Group A than in Group B (12.3 ± 0.3 vs. 11.8±0.7 fL). At T1, Group A showed significantly lower TSH (2.26 ± 0.5 µIU/mL), MPV (9.5 ± 0.3 fL), and total cholesterol (137.8 ± 29.2 mg/dL) and significantly higher FT4 (9.3 ± 0.4 pmol/L), PSV (40.0 ± 2.6 cm/s), and IIEF-5 score (20.2 ± 3.6) compared to pre-treatment values. None of these endpoints showed significant change at T1 compared to T0 in patients of group B.

Conclusions: Lt4 therapy is associated with an improvement of the erectile function at the vascular level, a decrease in MPV and total cholesterol. LT4 therapy should be considered in patients with arterial ED and SCH.

Keywords: erectile dysfunction; levo-thyroxine; mean platelet value; mean platelet volume (MPV).; peak systolic velocity; subclinical hypothyroidism.

Figure 1

Thyroid-stimulating hormone (TSH) and free-thyroxine (FT4) before (T0) and six months after levo-thyroxine (LT4) or administration or no treatment (T1). Serum TSH levels (A) significantly decreased and serum FT4 (B) significantly increased after six months of LT4 administration at the dose of 1 µg/kg/day in Group A. * p < 0.05.

Figure 2

Peak systolic velocity (PSV) of the cavernous artery and International Index of Erectile Function 5-item (IIEF-5) score before (T0) and six months after levo-thyroxine (LT4) or administration or no treatment (T1). PSV (A) and IIEF-5 score (B) significantly increased in patients of Group A treated with LT4 for six months. * p < 0.05.

Figure 3

Mean platelet volume (MPV) and total cholesterol at before (T0) and six months after levo-thyroxine (LT4) or administration or no treatment (T1). Serum MPV (A) and total cholesterol (B) significantly decreased after six months of LT4 administration at the dose of 1 µg/kg/day in Group A. * p < 0.05.