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CAUCI 2014 Immunohistochemical Evaluation of AR and Nerve Structure Density in Human Prepuce from PFS Patients Public Library of Science ONE .pdf

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Immunohistochemical Evaluation of Androgen Receptor
and Nerve Structure Density in Human Prepuce from
Patients with Persistent Sexual Side Effects after
Finasteride Use for Androgenetic Alopecia
Carla Di Loreto1, Francesco La Marra1, Giorgio Mazzon2, Emanuele Belgrano2, Carlo Trombetta2,
Sabina Cauci1*
1 Department of Medical and Biological Sciences, School of Medicine, University of Udine, Udine, Italy, 2 Urological Hospital Department, Department of Medical, Surgical
and Health Sciences, University of Trieste, Trieste, Italy

Finasteride is an inhibitor of 5-a-reductase used against male androgenetic alopecia (AGA). Reported side effects of
finasteride comprise sexual dysfunction including erectile dysfunction, male infertility, and loss of libido. Recently these
effects were described as persistent in some subjects. Molecular events inducing persistent adverse sexual symptoms are
unexplored. This study was designed as a retrospective case-control study to assess if androgen receptor (AR) and nerve
density in foreskin prepuce specimens were associated with persistent sexual side effects including loss of sensitivity in the
genital area due to former finasteride use against AGA. Cases were 8 males (aged 29–43 years) reporting sexual side effects
including loss of penis sensitivity over 6 months after discontinuation of finasteride who were interviewed and clinically
visited. After informed consent they were invited to undergo a small excision of skin from prepuce. Controls were 11
otherwise healthy matched men (aged 23–49 years) who undergone circumcision for phimosis, and who never took
finasteride or analogues. Differences in AR expression and nerve density in different portions of dermal prepuce were
evaluated in the 2 groups. Density of nuclear AR in stromal and epithelial cells was higher in cases (mean 40.0%, and 80.6%
of positive cells, respectively) than controls (mean 23.4%, and 65.0% of positive cells, respectively), P = 0.023 and P = 0.043,
respectively. Conversely, percentage of vessel smooth muscle cells positive for AR and density of nerves were similar in the 2
groups. The ratio of AR positive stromal cells % to serum testosterone concentrations was 2-fold higher in cases than in
controls (P = 0.001). Our findings revealed that modulation of local AR levels might be implicated in long-term side effects of
finasteride use. This provides the first evidence of a molecular objective difference between patients with long-term adverse
sexual effects after finasteride use versus drug untreated healthy controls in certain tissues.
Citation: Di Loreto C, La Marra F, Mazzon G, Belgrano E, Trombetta C, et al. (2014) Immunohistochemical Evaluation of Androgen Receptor and Nerve Structure
Density in Human Prepuce from Patients with Persistent Sexual Side Effects after Finasteride Use for Androgenetic Alopecia. PLOS ONE 9(6): e100237. doi:10.1371/
Editor: Domenico Coppola, H. Lee Moffitt Cancer Center & Research Institute, United States of America
Received January 7, 2014; Accepted May 24, 2014; Published June 24, 2014
Copyright: ß 2014 Di Loreto et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: Support was provided by University of Udine funds. The funders had no role in study design, data collection and analysis, decision to publish, or
preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
* Email:

tion of DHT is markedly increased, providing a rationale for
therapeutic 5 alpha-reductase inhibition in this disorder [8].
The molecular action of androgens is mediated by the androgen
receptor (AR), a member of steroid hormone receptors family
[9,10]. Testosterone or DHT binds to AR present in the cell
cytoplasm, the ligand binding activates the receptor to translocate
into the nucleus, homodimerize, and act as a transcription factor
binding specific DNA response elements called AREs (androgen
response elements) present in different target genes to mostly upregulate gene expression [4]. Thus, AR is responsible for
androgens physiological effects through activation of specific
androgen responsive genes [11]. Presently, it is questioned whether
blocking of T conversion to DHT by finasteride in prostate tissue
will change expression of AR [12].
According to the recent Mella and colleagues meta-analysis
[13], there is moderate quality evidence that inhibition of DHT

Finasteride is a synthetic 4-azasteroid molecule, used in the
treatment of both androgenetic alopecia (AGA) and benign
prostatic hyperplasia (BPH) [1]. Finasteride impedes the in loco
conversion of testosterone (T) into dihydrotestosterone (DHT) by
inhibiting the 5-a-reductase (5-a-R) enzyme, primarily the 5-a-R
type 2, in tissues and liver [1–3]. In adults, DHT is known to act as
primary androgen in prostate and hair follicles [1,2,4].
Androgens, in association with genetic factors, have been
involved in AGA pathogenesis [5,6]. Circulating and local
androgen hormones are considered a necessary (although not
sufficient) condition for the development of AGA. T and DHT
were demonstrated to induce apoptosis in dermal papilla cells
(DPC) in a dose-dependent and time-related manner [7]. In the
majority of men with male pattern baldness endogenous produc-



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Androgen Receptor and Post-Finasteride Syndrome

Cases were 8 patients enrolled after clinical consult (n = 5) or
through (n = 3), a forum collecting reports and
experiences of patients affected by persistent sexual side effects
after finasteride discontinuation. Eligibility criteria were: history of
finasteride use for AGA, sexual side effects including self-reported
loss of sensitivity in the genital area arose during or soon after
finasteride treatment and lasting 6 or more months after drug
discontinuation. Patients suffering from sexual disorders before
finasteride use, or who had any hormonal supplementation in the
last 6 months were excluded. All former finasteride users were
otherwise healthy, 2 of them were subsequently enrolled also into
the study by Melcangi and colleagues, for evaluation of steroid
levels in cerebrospinal fluid [20].
Eleven controls were enrolled among subjects undergoing
circumcision because of phimosis. Eligibility criteria for controls
were: healthy, AGA positive, with no history of finasteride or any
other drug capable of impairing androgens action use (like
dutasteride, saw palmetto, antidepressants, GnRH agonists,
isotretionin), and no use of hormonal treatments ever. Subjects
with any sexual dysfunction and/or chronic or acute diseases with
exception of phimosis were excluded from controls. Enrolled
subjects, i. e. both cases and controls, were evaluated for presence
of AGA by the Hamilton-Norwood scale through a questionnaire
reporting the pictures showing grades from 1 to 7; all enrolled
subjects had grade 2 or more [21].
Two different structured questionnaires were administered to
the former finasteride users (cases) to evaluate the development
and severity of persistent side effects. An ad-hoc questionnaire was
elaborated by the study authors to interview cases about
demographic and clinical characteristics, lifestyle habits, finasteride dosage, period of drug use, onset, type and duration of sideeffects. The duration of the finasteride therapy was calculated in
days of use. In particular, we asked patients to report in detail
every persistent symptom started during and/or soon after taking
finasteride and never experienced before finasteride use. We asked
also to provide a copy of any diagnostic exam performed in their
life. It is to note that all of them had some laboratory exams
performed after finasteride use, whereas none subject, except 1,
had any kind of laboratory exams performed before finasteride
use. No subject had alterations of liver or thyroid function tests.
Additionally, formers finasteride users filled the Arizona Sexual
Experience Scale (ASEX) questionnaire [22]. The ASEX questionnaire was chosen as validated instrument to assess sexual
function before and after taking finasteride. Possible total ASEX
scores range from 5 to 30, with the higher scores indicating more
severe sexual dysfunction. Sexual dysfunction is considered to be
present if the total score is $19 or if any one item is $5 or if any
three items are $4. We asked patients to complete ASEX citing
their symptoms at the moment of interview. Additionally, we asked
them to fill the ASEX questionnaire referring their condition
before taking finasteride.
Designing the study we observed that not all patients had
finasteride at the dosage exactly of 1 mg/day (Propecia dosage),
many patients used the dosage of 1.25 mg/day because they
preferred to buy the less costly 5 mg finasteride pills (Proscar) and
then to break them into four parts (of 1.25 mg each). For this
reason we decided to consider all of them.

synthesis by finasteride (usually at a dosage of 1 mg/day) is able to
prevent AGA progression and to increase hair density and quality
in male patients [13]. The main limit of finasteride use against
AGA is the onset of side effects [14]. More common adverse side
effects are: erectile dysfunction, loss of libido and ejaculation
disorders [13,15]. Less common side effects include anxiety,
depression, gynecomastia, and breast cancer in men [16]. Of
concern, recently, it has been reported that adverse side effects of
finasteride used to treat AGA might be persistent several months
or years after finasteride discontinuation [14,17–19]. The actual
incidence of this phenomenon is still to be determined, but such
negative events impairing sexual health in young males causes a
severe loss in terms of life quality [14,17]. In year 2011 a study by
Irwig and Kolukula [18] first characterized the types and duration
of persistent sexual side effects that occurred in 71 otherwise
healthy men during or immediately after taking finasteride for the
treatment of AGA. Most men developed sexual dysfunction in
multiple domains with 94% experiencing low libido, 92%
experiencing erectile dysfunction, 92% experiencing decreased
arousal, and 69% experiencing problems with orgasm [18].
Since June 2010 the pharmaceutical company (Merck) that
produces Propecia (finasteride 1 mg/day for AGA treatment)
included in the drug sheet as rare but possible side effects erection
disorders persistent after drug discontinuation, and infertility. In
April 2012, the US Food and Drug Administration required to
expand the list of persistent sexual adverse events indicated in the
labels for Propecia [16]. Of interest, many patients with long-term
adverse effects refer of skin discomfort in genital area; severity of
this effect in some cases is even described as a local paresthesia.
The origin of these phenomena is not known.
In the present study, we investigated the reasons of reduced or
altered sensitivity localized in the genital area in 8 men who took
finasteride to treat AGA and who also suffered from sexual
dysfunction including discomfort, numbness or even paresthesia of
the skin in the genital area, persistent loss of libido and erectile
dysfunction over 6 months after discontinuing finasteride treatment. To assess the sensitivity issue we collected foreskin samples
from all case patients to determine nerve density and we compared
the results with similar samples from 11 age-matched healthy
finasteride untreated controls that underwent circumcision to treat
phimosis. We also compared the AR tissue expression between the
2 groups and explored the relation between AR and the symptoms
showed by the case patients.

Patients and Methods
Ethics Statement
Enrolment and medical visits of all patients were performed at
the Urological Unit of University Hospital of Trieste, whereas
diagnostic analyses were carried out according to routine
laboratory procedures at the University Hospital of Udine. The
Institutional Ethical Committee of each participating institution
approved the study protocol, and all the subjects signed a written
informed consent before entering the study. The study was
conducted according to the principles expressed in the Declaration
of Helsinki.

Histological specimens

The study design was a retrospective case-control study. All
participants were white Caucasian males. Exclusion criteria for both
cases and controls were presence of obesity (BMI .30 kg/m2), any
acute or chronic disease like diabetes mellitus, hypertension,
cardiovascular diseases, thyroid diseases, autoimmune pathologies
and malignancies.

Prepuce samples were acquired from cases through punch
biopsy; a 5 mm square surface of skin, 2 to 4 mm deep was
acquired, while specimens of controls was obtained from
circumcision tissue. All specimens were retrieved by one physician.
Buffered formalin at 4% concentration was used to fix samples.

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Androgen Receptor and Post-Finasteride Syndrome

Table 1. Characteristics of 8 patients former finasteride users, finasteride self-reported side effects and sexual function

8 Cases n (%) or mean ± SD

Finasteride dose (1 mg per day), n (%)

4 (50.0)

Finasteride dose (1.25 mg per day), n (%)

4 (50.0)

Age at starting finasteride use (y)


Duration of finasteride use (days)


Discontinuation of finasteride (days)


Present ASEX score (points)


Pre-finasteride use ASEX score (points)


Loss of penis sensitivity, n (%)

8 (100)

Loss of penis pleasurable response to touch, n (%)

8 (100)

Loss of scrotum and/or testicles sensitivity, n (%)

7 (87.5)

Hardened tissue and/or rubbery texture, n (%)

7 (87.5)

Flaccidity, wrinkledness and retraction into the scrotum, n (%)

7 (87.5)

Erectile dysfunction, n (%)

7 (87.5)

Pain in penis and/or scroto or testis, n (%)

6 (75.0)

Reduced penis dimension, n (%)

6 (75.0)

Reduced scroto or testis dimension, n (%)

5 (62.5)

Reduced ejaculate volume, n (%)

5 (62.5)

Reduced pubic hair, n (%)

4 (50.0)

P valuea


History of low total testosterone detected once after finasteride discontinuation and before present study entry 1 (12.5)
History of low free testosterone detected once after finasteride discontinuation and before present study entry 4 (50.0)
Tadalafil (Cialis) post-finasteride use, n (%)

5 (62.5)

Use of testosterone supplementation after finasteride discontinuation,b n (%)

3 (37.5)

Use of benzodiazepines after finasteride discontinuation, n (%)

2 (25.0)


Comparison between present and pre-finasteride use ASEX scores, 2-sided P value was evaluated by the Mann-Whitney U-test.
Testosterone supplementation post-finasteride was terminated over 1 year before present study entry.

Both a hematoxylin and eosin stain and an immunohistochemistry
slides were acquired for all samples. The primary antibody used to
mark the AR was Androgen Receptor Clone AR 441, murine
monoclonal M3562 (Dako A/S, Denmark). To obtain immunohistochemistry slides Autostainer Ling 48 was used (Dako A/S,
Denmark). We used Envision+/HRP rabbit/mouse polymer as
detection system. We then performed through light microscopy a
semi-quantitative evaluation of AR expression in epithelial,
stromal and vessel smooth muscle cells. Percent of cells of each
type positive for nuclear AR were reported.
We also estimated nerve density on hematoxylin and eosin
stained slides. For this purpose, each nerve seen in the slide was
counted as one. All the reported figures were the average of 25
different fields at 206 magnification. All evaluations were
performed by an expert physicians blinded to subjects characteristics.
Testosterone was measured in the venous blood serum by
competitive chemiluminometric immunoassay on the automated
Advia Centaur CP-Siemens Healthcare analyzer with reference
interval 8.4–28.7 nmol/L, free testosterone was calculated by
Vermuelen et al. 1999 method [23], reference interval was 200–
800 pmol/L.

results from categorical variables. Two-sided Spearman’s Rho
coefficient was used to assess correlations of continuous values.
Two-sided P values ,0.05 were considered significant. Statistical
analyses were performed by SPSS (Statistical Package for Social
Sciences) software.

Characteristics of 8 cases (former finasteride users having longlasting sexual side effects) along with results from the questionnaires and clinical visit, were summarized in Table 1. Patients self
reported shrinkage of the penis. Former finasteride users were 29–
43 years old, all were single, none declared himself as homosexual
or bisexual. Patients started finasteride use in the age range of 22–
32 years, half took finasteride 1 mg/day, and half had 1.25 mg/
day. All these patients spontaneously declared that finasteride use
effectively stopped their hair loss. Finasteride was assumed on
average for nearly 32 months (i. e. almost 3 years), with a range
from 49 to 3100 days. In all subjects adverse side effects persisted
for over 6 months after finasteride discontinuation and were still
affecting the patients at the time of the visit day for study
enrolment. Patients were enrolled on average at nearly 56 months
(i.e. almost 5 years), with a range from 240 to 3010 days after drug
discontinuation. All patients claimed insensitivity in the genital
area and had ASEX score $19 indicating sexual dysfunction. In
particular, all of the 8 patients had loss of penis sensitivity and loss
of pleasurable response to touch, 7 out of 8 cases (87.5%) had loss

Statistical analysis
Continuous data were expressed as mean and standard
deviation. Mann–Whitney U test was used to compare results
from continuous variables. Fisher’s test was used to compare


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Androgen Receptor and Post-Finasteride Syndrome

of scrotum and/or testicles sensitivity, hardened tissue and/or
rubbery texture, flaccidity, wrinkledness and retraction into the
scrotum, and erectile dysfunction. All cases except 2 reported
reduced penis dimension and declared pain in penis and/or scroto
or testis. Collection of medical history data revealed that 1 patient
had a documented history of low serum total testosterone and 4
had a documented history of low serum free testosterone after
finasteride use but before present study entry. Neither patient
measured serum hormone levels, nor had health provider
consultation for any sexual symptom before finasteride use. None
patient declared use of drugs to augment sexual functions before
finasteride use, whereas 5 used tadalafil (Cialis) after finasteride
Comparison of characteristics, immunohistochemical and
serum total and free testosterone levels in cases and controls were
illustrated in Table 2. Controls were 23–49 years old, they did not
differ in age and BMI from cases. Controls were more frequently
married than cases (P = 0.045), none declared himself as homosexual or bisexual, they had no sexual disturbance except
discomfort due to phimosis; none declared use of drugs to
ameliorate erectile functions.
The percentage of cells positive to AR in the nuclei of epithelial,
stromal and vessel smooth muscle cells, were evaluated by
immunohistochemistry, examples were reported in Figure 1,
panels from A to F. Percentage of epithelial cells (basal cells of
the epidermis) positive for nuclear AR was higher in cases
(mean6SD, 80.668.63%) than in controls (mean6SD,
65.0619.1%), P = 0.043. Stromal cells in cases showed an almost
2-fold greater expression of AR in the nuclei compared to controls
(mean6SD, 40.0615.1% in cases versus 23.468.68% in controls),
P = 0.023. Percentage of AR positive vessel smooth muscle cells
did not differ between the 2 groups. The average of AR positive
cells in the 3 kind of tissues was higher in cases than in controls,
P = 0.007 (Table 2).

Figure 1. AR positive cells (by brown staining): (A) case, (B)
control in epithelial cells; (C) case, (D) control in stromal cells; (E) case,
(F) control in vessels smooth muscle cells. Nerves in foreskin tissue from
a case (G) and a control (H).

Panels G and H in Figure 1 show representative pictures of
nerve densities in a case (Panel G) and a control (Panel H) subject.

Table 2. Comparison of demographics features, immunohistochemical findings and serum hormonal levels between 8 cases and
11 controls.


Cases n = 8

Controls n = 11

P valuea

Age (y)




BMI (kg?m22)




University Education, n (%)

7 (87.5)

7 (63.6)


High school, n (%)

1 (12.5)

4 (36.4)


Married or stable partner, n (%)

0 (0)

5 (45.5)


Smoker, n (%)

3 (37.5)

5 (45.5)


Nuclear AR positive epithelial cells (%)




Nuclear AR positive stromal cells (%)




Nuclear AR positive vessel smooth muscle cells (%)



Average tissue AR positive cells (%)




Nerves density (%)




Total testosterone (nmol/L)




Total testosterone below 8.4 nmol/L, n (%)

1 (12.5)

0 (0)


Free testosterone (calculated) (pmol/L)




Free testosterone (calculated) below 200 pmol/L, n (%)

2 (25.0)

0 (0)


Ratio of AR positive stromal cells (%) and serum total testosterone (nmol/L)




Ratio of AR positive stromal cells (%) and serum free testosterone (pmol/L)




Two-sided P values to assess differences of continuous variables and of categorical variables were tested by means of the Mann-Whitney U-test or the Fisher’s exact
test, as appropriate.



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Androgen Receptor and Post-Finasteride Syndrome

Histological evaluation of nerve density revealed that patients
showed similar density compared to controls (Table 2).
Serum total testosterone concentration was slightly lower, but
not significant different, in cases than in controls. Similarly, free T
(calculated according to [23]) concentrations were slightly lower,
but not significant different, in cases compared to controls. Only 1
case but none control had total T concentration lower than
normal value (8.4 nmol/L). Moreover, 2 cases but none control
had free T concentration lower than normal value (200 pmol/L).
To roughly estimate the effect of circulating testosterone on
local AR expression we evaluated the ratio of immunohistochemically determined AR in tissues and serum total T or free T.
Interestingly, as reported in Table 2, the ratio of AR positive
stromal cells (%) and serum T was 2-fold higher in patients than in
controls (P = 0.001). Similarly, the ratio of AR positive stromal
cells (%) and serum free T was 2-fold higher in patients than in
controls (P = 0.005).
Analysis of bivariate correlations between sexual dysfunction in
former finasteride users as described by the ASEX score points
and laboratory biomarkers continuous values highlighted that
present ASEX points were inversely related to % of AR positive
stromal cells (Rho = 20.722, P = 0.043). This effect was even
stronger considering as variable the difference between present
and pre-finasteride use ASEX score in relation to AR in stromal
cells (Rho = 20.913, P = 0.002). Contrariwise, ASEX score before
finasteride use was not correlated to AR in stromal cells (Rho
= 0.118, P = 0.781).
Finally, the ratios of AR positive stromal cell (%) over total T
concentrations and over free T concentrations had a strong inverse
relationship with the variable ASEX difference (present minus prefinasteride ASEX points), Rho = 20.988, P,0.001; and Rho =
20.855, P = 0.007, respectively.

which showed significant upregulation of ARs by finasteride
treatment for 30–180 days [12]. Additionally, in an androgendependent prostate cancer cell line (LNCaP) cells treated by
finasteride significant in vitro upregulation of ARs was demonstrated [12,32].
The unexpected result of our present study is that the AR
upregulation was detectable in the dermis of subjects long after
discontinuation of finasteride use, on average at almost 5 years
(mean 1672 days) of drug wash-out, in a range from 8 months to
over 8 years (240 to 3010 days). Contrariwise, the hormonal
alteration effects of finasteride have been reported to be shortly
reversible. In fact, according to drug information provided by
Lexi-Comp., after 6 months of treatment with 5 mg/day
finasteride the circulating DHT levels are reduced to castrate
levels without significant effects on circulating testosterone and
levels return to normal within 14 days of discontinuation of
treatment [16].
An intriguing observation of our study was that the ratio of AR
positive stromal cells (%) to serum total or free testosterone was 2fold higher in former finasteride users than controls. This finding
could indicate the presence in former finasteride users of an
augmented regulatory feedback loop that normally serves to
modulate hormonal responses [33–35]. Such amplification of AR
levels in respect to serum testosterone levels could derive from
hormonal ipo-response in the genital tissues. However, we cannot
presently exclude that this apparent upregulation of AR expression
is due to local low levels of androgens (particularly DHT) [36].
Indeed, it is known that androgens themselves can regulate AR
transcription both in a positive and a negative way. T and DHT
may down-regulate AR mRNA by decreasing its transcription; on
the other hand androgens can increase AR half life by stabilizing
the receptor in its dimer form [33,34]. In addition, finasteride can
directly bind to AR just as T, thus, finasteride may act directly as a
competitor to androgens and exert an inhibiting role. Finasteride
effects as an inhibitor are reported as light but stable [37].
In general, the AR levels can be modulated by several factors
[38,39]. Our unexpected observation that percentage of AR
positive stromal cells is inversely related to ASEX score, suggests
that patients less able to raise AR are those with more severe side
effects related to sexual dysfunction. This seems to support the
hypothesis that the body tries to compensate local androgens
deprivation by producing more androgen receptors. Notably, 2 of
our patients were found to have low androgen levels in the
cerebrospinal fluids by Melcangi et al. [20]. Further studies are
needed to assess these complex issues. The design of our study does
not allow determining whether the AR in the nuclei of patients is
indeed able to properly act as transcription factor like in healthy
subjects. It cannot be excluded, for example, that epigenetic
changes [39–45] induced by finasteride use could have modified
the transcriptional activity of AR present in the nuclei, which is
potentially able to modulate around 500 AREs and 200 AR
responsive genes [46].
Most of our patients suffered erection disorders. Erection is a
complex process involving androgens actions and also important
signaling in the brain [47–49]. It is generally accepted that
androgens are really important in masculine behaviour, although
the relation between testosterone concentrations and sexual
behaviour is not well understood. Some authors [50] suggested a
possible mechanism for lack of androgens induced by 5-a-R
inhibitor therapy to cause erectile dysfunction. Hypoandrogenism
is believed to cause corpora cavernosa fibrosis through collagen
fibres deposition and inhibition of nitric oxide synthases [50,51].
Moreover, Zhang and colleagues [52] demonstrated that 5-a-R
inhibitor therapy attenuates erectile function by promoting

Finasteride is still one of the most common therapeutic drugs
prescribed for AGA, a distinctive alopecia pattern involving
hairline recession and vertex balding, a condition more frequent
with increasing age [24–26]. An European study found moderate
to extensive male pattern hair loss in approximately 12% of men
aged 18 to 40 years [27]. Finasteride therapy against AGA (at
1 mg/die, for 3 months or longer) is usually given to younger men
than against prostatic disorders (at 5 mg/die) [28,29]. Finasteride
was proposed for treatment of adolescent androgenic alopecia
[30], and hidradenitis suppurativa in children and adolescent [31].
However, treatment of young subjects is of increasing concern due
to accumulating evidence that daily use of oral finasteride has
several severe adverse effects [13,14,17–19].
Our main finding was the assessment of a significant increase of
AR nuclear levels in some types of cells, specifically, stromal and
epithelial cells, in dermis samples of foreskin from patients with
major sexual adverse side-effects long after use of finasteride (on
average almost 5 years later). As our patients are suffering from
symptoms suggestive of local androgens deficiency, it was
important to assess if this phenomenon was due to intrinsic
inability to express and/or translocate the AR into the cell nuclei,
specifically in the genital tissues. Our present data permit to
exclude an impairment of this kind, at least in the foreskin. It is to
note also that our data indicate that AR levels in nuclei of vessel
muscle cells were similar in cases and controls, thus the increase in
AR observed in former finasteride users was tissue specific. Our
observation is apparently in line with an immunohistochemical
study performed on 47 cases of BPH treated with finasteride
(5 mg/die) analyzed before transurethral resection of the prostate,


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Androgen Receptor and Post-Finasteride Syndrome

apoptosis in the cavernous smooth muscle cells of aged rats,
suggesting a new role for androgen in maintaining the structural
and functional integrity of the erectile organ.
Since finasteride inhibits T conversion into DHT, which is
responsible for most androgen activity, it is plausible that
prolonged finasteride use in predisposed individuals could simulate
the effects of aging in young men. Since some of the effects of
androgen inhibition can not be reversed once local androgen levels
are re-established, it is temping to speculate that patients could still
suffer from adverse sexual effects several months or even
permanently after finasteride discontinuation because of aging
effects caused prematurely by androgens deprivation, namely by
artificially reduced DHT concentrations. Indeed, 2 of our patients
were found to have low DHT levels in the cerebrospinal fluids long
after finasteride discontinuation by Melcangi et al. [20].
Our study has several limitations, first limitation is the small
number of subjects enrolled, which is derived in part by the strict
selection of patients, which had to show severe side-effects
including specifically loss of sensitivity in the genital area persistent
for more than 6 months after drug discontinuation, a symptom
that had to be totally absent before finasteride use.
A second limitation is due to the impossibility to determine
DHT levels, especially locally, which could help in interpretation
of results. Finasteride is a drug which specifically dampens DHT
levels [53]. DHT has a 10-fold higher potency of inducing AR
signalling than T, and reduction of DHT and neurosteroids by
finasteride may influence sexual behavior [14,54]. In fact, it was
demonstrated that in patients with male-pattern baldness treatment with finasteride is effective in reducing local DHT/T in scalp
hair [5]. Consistently, DHT was formed in negligible amounts in
fibroblasts cultured from the genital skin of a patient with 5 alphareductase deficiency [55].
A third limitation of our study was the absence of genetics
evaluation of polymorphisms in the AR gene, that can potentially
be responsible for alterations in AR expression, and which can also
determine AGA [56]. However, in part, we avoided this
confounding by enrolling matched controls with levels of AGA
similar to those declared by patients before assuming finasteride.
Indeed, a very recent paper demonstrated no difference in AR
polymorphisms between patients with post-finasteride syndrome
(PFS) and untreated controls having AGA [57].
Finally, an obvious limitation of our study is due to the
retrospective design, thus, we had no samples available for
measurements from patients before and/or during finasteride use.

On the other hand, strength of our study is that we documented
severe sexual side-effects in patients who were carefully clinically
examined by an expert andrologist. It is to note that other studies
on long term side-effects of finasteride used against AGA collected
information by internet or phone call on subjects that self-reported
symptoms [17,18].
An important issue related to loss of sensitivity in the penis and
scrotal/testicular area was to explore if this condition was the
consequence of an alteration in nerve density. We demonstrated
that cases and controls had similar nerve densities, thus no
structural nerve alteration seems responsible for this kind of
finasteride side-effect. Interestingly, in a rat model, finasteride
treatment for 4 weeks reduced the weight of the corpus
cavernosum but appears not to affect the erectile responses to
electrical stimulation of the cavernous nerve [49]. The long-term
effects of finasteride on both central and peripheral neural
pathways of erection will require further investigations. In fact, it
is known that androgens and AR have roles in regrowth of
peripheral nerves and AR is also expressed in the central nervous
system [40,58–60].
Our study was the first to document an alteration of AR levels in
genital tissues from young patients with long-term adverse sexual
effects after finasteride use against AGA. Further enlarged studies
will be necessary to better assess which are the causative factors of
persistent sexual side effects observed in some men who used
finasteride against AGA. A better knowledge of molecular events
occurring during and/or after finasteride use could suggest
possible remedies against severe sexual side-effects in fertile age
young men.

We gratefully thank all volunteers who accepted to participate to the study
and Dr. Maria Cristina Carloni, MD, for help in patient enrolment. We
thank Dr. Vincenzo Maione, MD, and Dr. Antonio Paolo Beltrami. MD,
for critically reading the manuscript.

Author Contributions
Conceived and designed the experiments: CD SC CT EB. Performed the
experiments: CD FL GM CT. Analyzed the data: SC FL. Contributed
reagents/materials/analysis tools: CD CT SC. Wrote the paper: SC FL

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