M C Lardone

University of Santiago, Chile, CiudadSantiago, Santiago, Chile

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Publications (13)33.74 Total impact

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    ABSTRACT: Objective To determine whether decreased testicular levels of enzymes necessary for retinoic acid biosynthesis were associated with male infertility, as retinoic acid is known to be necessary for spermatogenesis. Design Observational analysis of testicular tissue samples, sperm indices, and serum hormone concentrations. Setting Two infertility centers in Chile. Patient(s) 32 infertile men and 11 control men. Intervention(s) Measurement of the three enzymes necessary for retinoic acid biosynthesis, aldehyde dehydrogenase (ALDH) 1A1, 1A2, and 1A3, in testicular tissue by a novel liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) peptide assay. Main Outcome Measure(s) ALDH isozyme levels compared by type of infertility and correlated with testicular germ cell numbers, sperm parameters, and serum and intratesticular hormone concentrations. Result(s) Men with infertility had statistically significantly reduced levels of ALDH1A2 but not ALDH1A1 or ALDH1A3 in their testicular tissue compared with men with normal spermatogenesis. The ALDH1A2 protein levels were strongly correlated with the number of germ cells found via testicular biopsy. Conclusion(s) These findings suggest that ALDH1A2 is the enzyme involved in retinoic acid biosynthesis in human germ cells. Further study of the relationship between intratesticular ALDH1A2 and male infertility is warranted to determine whether men with infertility have a reduced ability to synthesize retinoic acid within their germ cells that could impair spermatogenesis.
    Fertility and sterility 01/2014; · 3.97 Impact Factor
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    ABSTRACT: PURPOSE: To determine the prevalence of South Amerindian Y chromosome in Chilean patients with spermatogenic failure and their association with classical and/or AZFc-partial Y chromosome deletions. METHODS: We studied 400 men, 218 with secretory azo/oligozoospermia (cases) and 182 controls (116 fertile and/or normozoospermic, and 66 azoospermic with normal spermatogenesis). After a complete testicular characterization (physical evaluation, hormonal and/or biopsy) peripheral blood was drawn to obtain DNA for Y chromosome microdeletions, AZFc-partial deletions and biallelic analysis by allele specific polymerase chain reaction (PCR) of the M3 (rs3894) single nucleotide polymorphism (SNP). RESULTS: Classical AZF microdeletions were found in 23 cases (Y-microdeleted). AZFc-partial deletions were observed in 10 cases (6 "gr/gr", 3 "b2/b3" and 1 "b1/b3") and 4 controls (4 "gr/gr"). The AZFc-partial deletions were mainly associated with the absence of DAZ1/DAZ2 (64 %). No significant differences in the prevalence of AZFc-partial deletions were observed between cases and controls. We observed a significant higher proportion of the Q1a3a haplogroup in Y-microdeleted men compared to patients with spermatogenic failure without deletions and control men (P < 0.01 and P < 0.05, respectively by Bonferroni test). Among them, patients with AZFb deletions had an increased prevalence of the Q1a3a haplogroup compared to controls, cases without deletions and to those with complete or partial-AZFc deletions (P < 0.01, Bonferroni test). CONCLUSIONS: The Q1a3a South Amerindian lineage seems to increase the susceptibility to non AZFc microdeletions. On the other hand, in Chilean population the AZFc-partial deletions ("gr/gr", "b1/b3" and/or "b2/b3") does not seem to predispose to severe spermatogenic impairment.
    Journal of Assisted Reproduction and Genetics 02/2013; · 1.82 Impact Factor
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    ABSTRACT: We characterised and correlated the histological and hormonal aspects of a cohort of 261 azo/oligozoospermic men, applying a quantitative/qualitative evaluation of testicular tissue and serum and intratesticular hormonal measurements. One hundred and 93 azo⁄oligozoospermic patients were diagnosed as: complete sertoli cell only syndrome (cSCOS), n = 76; focal SCOS, n = 31; maturation arrest, n = 34; hypospermatogenesis, n = 17; mixed atrophy, n = 25; and severe atrophy, n = 10. Normal spermatogenesis was observed in 68 infertile men (controls). Patients with cSCOS, focal SCOS, mixed and severe atrophy had larger LC/clusters (11.5; 11.0; 10.7; 18.9 LC/cluster) than controls (6 LC/cluster; P < 0.001). cSCOS, focal SCOS, mixed and severe atrophy patients had higher FSH, LH and lower T/LH ratio serum levels than the other groups. Intratesticular testosterone concentrations were higher in tissues with complete or focal SCOS (45.6 ng mg(-1) protein) and mixed atrophy (79.0 ng mg(-1) protein) than normal tissues (20.3 ng mg(-1) protein; P = 0.03 and P = 0.007). Considering all subjects, significant correlations were found between T/LH ratio and Leydig cells/cluster (r = 0.510, P < 0.001), FSH levels (r = -0.692, P < 0.001) and with intratesticular testosterone (r = -0.354, P = 0.001); these correlations follow the pattern of severity of spermatogenic damage. By a thorough histological evaluation, we validate the concept that the severity of spermatogenic impairment is associated with major morphological and functional disturbance of the Leydig cell compartment.
    Andrologia 09/2012; · 1.55 Impact Factor
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    ABSTRACT: The etiology of hypospadias is multifactorial. Abnormal androgenic secretion and/or action during the development of external genitalia may be involved in the etiology of this congenital malformation. This study explored CAG and GGN polymorphisms in the androgen receptor (AR) gene, which may affect its transcriptional activity, in patients with isolated hypospadias. The length of the CAG/GGN polymorphisms was determined in 44 boys with non-severe (glandular) or severe (penile or penoscrotal) isolated hypospadias and with a normal hormonal evaluation. In addition, 79 healthy men, as controls, were studied. Mean CAG repeats were significantly higher in total and severe cases compared to controls (24.4 +/- 2.8 and 24.7 +/- 3.1 vs. 22.7 +/- 3.3, respectively; p<0.05, Student's t and Bonferroni test). In addition, a frequency of CAG alleles >23 was significantly different in total and severe cases compared to controls (70.5% and 74.1% vs. 39.2%, respectively, p<0.05, chi2 and Bonferroni test). The median number and the distribution of GGN polymorphisms were similar in cases and controls. Boys with isolated hypospadias have longer CAG alleles in their AR, which may be related with the development of this congenital malformation.
    Journal of pediatric endocrinology & metabolism: JPEM 01/2012; 25(1-2):157-62. · 0.75 Impact Factor
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    ABSTRACT: DAX-1 [dosage-sensitive sex reversal-adrenal hypoplasia congenital (AHC) critical region on the X chromosome gene 1; NR0B1] is an orphan nuclear receptor that acts as a transcriptional repressor in adrenal/gonadal development, steroidogenesis and probably spermatogenesis. An alternatively spliced form called DAX-1A (NR0B1A) has been described in several tissues including the testis, and in vitro studies have shown an inhibitory effect on DAX-1 transcriptional function. We aimed to study the mRNA and protein expression of DAX-1 in testicular tissues of 65 men with primary spermatogenic failure [complete Sertoli cell only syndrome (SCOS), focal SCOS, maturation arrest and mixed atrophy] compared with 33 controls with normal spermatogenesis. As a novel finding, we observed intense immunostaining, not only in the nucleus of Sertoli cells, but also in pachytene spermatocytes and round spermatids. The quantitative mRNA expression of DAX-1 and DAX-1A was similar between cases and controls and was not associated with the levels of gonadotrophins and steroids. Moreover, DAX-I transcript expression level was ∼750-fold higher than DAX-1A, and there was a strong positive correlation between them (r = 0.52; P< 0.001). We conclude that, in addition to Sertoli cells, DAX-1/DAX-1A is expressed in germ cells from spermatogonia to round spermatids. Besides, the similar mRNA expression of DAX-I and DAX-IA in testicular tissues from cases and controls does not support the involvement of DAX-1 in the etiology of primary spermatogenic failure. Finally, the low level of expression of the alternative transcriptional variant DAX-1A would not support its putative inhibitory function in vivo.
    Molecular Human Reproduction 07/2011; 17(12):739-46. · 4.54 Impact Factor
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    ABSTRACT: Androgens are essential for spermatogenesis. It has been postulated that androgen activity is modulated directly or indirectly by genetic variability in the androgen receptor gene sequence, including CAG/GGN polymorphisms and single-nucleotide polymorphisms (SNP). In this study, the frequency of 6 SNPs that constitute a haplotype in the androgen receptor sequence was determined by enzyme restriction assays and allele-specific polymerase chain reactions in 117 secretory azo/oligozoospermic men (93 idiopathic and 24 excryptorchidic), and in 121 controls with normal spermatogenesis (42 obstructive and 79 normozoospermic men) whose hormonal measurements and length of CAG/GGN polymorphisms were previously determined. The frequency of these 6 SNPs was not different between patients and controls. A total of 10 haplotypes (HAPs 1-10) formed by these 6 SNPs were found, and one of these haplotypes was observed with high frequency in the total population (HAP1, 83.2%; P < .001, χ(2) test). The frequency of the 10 haplotypes was not different between patients and controls, except for HAP5, which was only detected in one patient with a history of bilateral cryptorchidism (P = 0.014, Bonferroni test). On the other hand, no associations were found between the haplotypes studied and shorter or longer CAG or GGN polymorphisms. Interestingly, we found that the CAG 21 allele, which was previously correlated with an increased risk of idiopathic spermatogenic impairment, was more frequently found among the less common haplotypes that have higher follicle-stimulating hormone serum levels. In summary, we did not find an increased frequency of particular haplotypes in infertile men with idiopathic spermatogenic impairment compared with control men; however, we found that the CAG 21 allele, which appears to be associated with male infertility, is observed at a significantly higher proportion among the less common androgen receptor haplotypes.
    Journal of Andrology 03/2011; 33(1):88-95. · 2.53 Impact Factor
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    ABSTRACT: To describe genetic evaluation and response to surgery and letrozole therapy of a 46,XX/SRY-negative true hermaphrodite. Case report. University Medical Center. Nineteen-year-old male with penile hypospadias, micropenis, and crytorchidism at the time of birth. Unilateral gonadectomy, and contralateral conservative gonadal surgery, followed by therapy with letrozole. Histopathologic, genetic and hormonal studies. Genetic analysis showed that the subject was 46,XX/SRY-negative. Gonadectomy of the left gonad was performed at 16 years. The gonad resected was an ovotestes. The patient's estradiol was high (492±25 pmol/L), whereas the testosterone was low (4.2±0.5 nmol/L). Nineteen months later, conservative gonadal surgery of the contralateral gonad was performed to resect ovarian tissue, and treatment with letrozole was started. During letrozole treatment, testosterone was significantly increased (8±0.7 nmol/L), but estradiol was not changed (323±118 pmol/L). After letrozole withdrawal, testosterone did not decreased significantly (6.9±0.4 nmol/L), estradiol showed an oscillating pattern and a gonadal ultrasound showed an ovoid structure, which appeared to correspond to a follicle. At that time, estradiol was elevated (393 pmol/L). We present the case of a 46,XX/SRY-negative phenotypic male with bilateral ovotestes. Conservative gonadal surgery should be performed only when all ovarian tissue can be resected. Our results suggest that letrozole is not an adequate treatment for 46,XX true hermaphrodite males with ovotestes.
    Fertility and sterility 05/2010; 94(6):2330.e13-6. · 3.97 Impact Factor
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    ABSTRACT: There is ample documentation supporting the fact that androgens are required for normal spermatogenesis. A minority of infertile men have abnormal testosterone blood levels or mild androgen receptor mutations. We investigated the androgen receptor CAG and GGN repeat lengths in Chilean men with spermatogenic impairment. We studied 117 secretory azoospermic/oligozoospermic men (93 idiopathic and 24 excryptorchidic), without Y-chromosome microdeletions, and 121 controls with normal spermatogenesis (42 obstructive and 79 normozoospermic men). Peripheral blood was drawn to obtain genomic DNA for polymerase chain reaction and automated sequencing of CAG and GGN repeats. Testicular characterization included hormonal studies, physical evaluation, and seminal and biopsy analysis. The CAG and GGN polymorphism distributions were similar among idiopathic men, excryptorchidic men, and controls and among the different types of spermatogenic impairment. However, the proportion of the CAG 21 allele was significantly increased in idiopathic cases compared to controls (P = .012 by Bonferroni test, odds ratio = 2.99, 95% confidence interval, 1.27-7.0) and the CAG 32 allele only was observed in excryptorchidic patients (P < .0002, Bonferroni test). Idiopathic cases with Sertoli cell-only syndrome showed the highest proportion of the CAG 21 allele (P = .024, χ(2) test). On the other hand, in idiopathic cases and controls the most common GGN allele was 23, followed by 24, but an inverse relation was found among excryptorchidic cases. The joint distribution of CAG and GGN in control, idiopathic, and excryptorchidic groups did not show an association between the 2 allele repeat polymorphisms (P > 0.05, χ(2) test). Our results suggest that the CAG 21 allele seems to increase the risk of idiopathic Sertoli cell-only syndrome. Moreover, the GGN 24 allele could be contributing to deranged androgen receptor function, associated with cryptorchidism and spermatogenic failure.
    Journal of Andrology 04/2010; 31(6):552-9. · 2.53 Impact Factor
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    ABSTRACT: There is evidence that impaired spermatogenesis is associated with an imbalance in the oestradiol/testosterone ratio and with Leydig cell (LC) dysfunction. In testis, P450-aromatase, encoded by CYP19, is responsible for the conversion of testosterone to oestradiol. The aims of this study were to quantify CYP19 mRNA expression, aromatase activity and protein localization, and to measure the oestradiol to testosterone ratio in testicular tissues of men with spermatogenic impairment. Twenty-four men with complete Sertoli cell-only syndrome (SCOS), 14 with focal SCOS, 14 with maturation arrest (MA), 8 with mixed atrophy and 30 controls with normal spermatogenesis were subjected to testicular biopsy. All subjects underwent a physical examination, cytogenetic and serum hormonal studies. Testicular CYP19 mRNA was quantified using real time RT-PCR. Testicular aromatase activity was measured using the (3)H(2)0 assay and protein expression was evaluated using immunohistochemistry. In cases, serum testosterone and oestradiol were normal, but the testosterone/LH ratio was lower compared with controls (p < 0.05). Aromatase was localized in the Leydig, Sertoli and germ cells of all tissues, although stronger intensity was observed in LC. Aromatase mRNA and activity were not altered in cases and correlated positively with LC number (r = 0.516 and r = 0.369; p < 0.008). The intratesticular oestradiol/testosterone ratio was elevated (p = 0.005) in complete SCOS patients compared with controls. In conclusion, testicular aromatase seems to be normal in most subjects with impaired spermatogenesis. However, an altered intratesticular oestradiol/testosterone ratio in some patients with complete SCOS suggests that aromatase is increased, which might contribute to Leydig cell dysfunction.
    International Journal of Andrology 11/2009; 33(4):650-60. · 3.57 Impact Factor
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    ABSTRACT: To determine the prevalence of AZFc subdeletions in infertile Chilean men with severe spermatogenic impairment. Prospective analysis. University infertility clinic. Ninety-five secretory azo/oligozoospermic men without AZFc Y chromosome microdeletions: 71 whose testicular histology showed severe spermatogenic impairment and 24 who exhibited reduced testicular volume and elevated serum FSH levels. As controls, we studied 77 men (50 fertile and/or normozoospermic, and 27 with azoospermia and normal spermatogenesis). Peripheral blood was drawn to obtain genomic DNA for polymerase chain reaction (PCR) digestion assays of DAZ-sequence nucleotide variants and for AZFc-STS PCR after a complete testicular characterization (biopsy, hormonal, and physical evaluation). DAZ genes and AZFc subdeletion types. In cases we observed two "gr/gr" subdeletions (2.1%), one with absence of DAZ1/DAZ2 (g1/g2 subtype), and the other with absence of DAZ3/DAZ4 (r2/r4 subtype). Additionally, we found a g1/g3 subdeletion in a patient with Sertoli-cell-only syndrome. In controls, we observed two gr/gr subdeletions with absence of DAZ1/DAZ2 (2.6%) in a fertile/normozoospermic and in an obstructive azoospermic man. AZFc subdeletions do not seem to cause severe impairment of spermatogenesis. Moreover, gr/gr-DAZ1/DAZ2 subdeletions do not appear to affect fertility in Chilean men.
    Fertility and sterility 11/2007; 88(5):1318-26. · 3.97 Impact Factor
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    ABSTRACT: Y chromosome microdeletion is the most important genetic cause of impairment of spermatogenesis. Nevertheless, a significant proportion of patients with spermatogenic failure do not have this condition. This study investigated the expression level of AZF genes, DDX3Y (DBY), RBMY1, DAZ and TSPY in testicular tissues of 42 subjects with impaired spermatogenesis compared with 33 with normal spermatogenesis. Histopathological evaluation was performed in all subjects and tissues were classified according to Johnsen Score. Transcript amounts were determined by quantitative-competitive RT-PCR. Patients with complete Sertoli cell-only syndrome (SCOS) did not exhibit RBMY1, DAZ and TSPY gene expression, however, we detected very low expression of DDX3Y transcript. Tissue samples with focal SCOS showed significantly decreased expression of all genes (P < 0.001). Maturation arrest and hypospermatogenesis tissues expressed significantly low levels of DDX3Y testicular transcript (P < 0.001), while the mRNA levels of the other genes were similar to that in tissues from the normal spermatogenesis group. Negative or diminished gene expression of DDX3Y, RBMY1, DAZ and TSPY in tissues samples with SCOS or focal SCOS reflects the absence or the lower number of germ cells, respectively. The finding that the testicular transcript of DDX3Y is significantly decreased in patients with severe spermatogenenic failure, especially in those presenting maturation arrest, suggests an important role of DDX3Y during spermatogenesis.
    Molecular Human Reproduction 11/2007; 13(10):705-12. · 4.54 Impact Factor
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