Primary male infertility in Kuwait: a cytogenetic and molecular study of 289 infertile Kuwaiti patients.

Infertility is one of the major public health problems, affecting 15% of couples who attempt pregnancy; in 50% of these, the male partner is responsible. Chromosomal abnormalities and Y microdeletions in the azoospermia factor (AZF) region are known to be associated with spermatogenetic failure. In the present study, 289 patients with primary male infertility because of spermatogenetic failure were studied in order to highlight the molecular background of male infertility in Kuwait, and to avoid the possibility of transmission of any microdeletions/chromosomal aberrations to offspring via intracytoplasmic sperm injection (ICSI). Of the 289 infertile men, 23 patients (8%) had chromosomal aberration in the form of Klinefelter syndrome/variant (16/23; 69.6%), XYY syndrome (3/23; 13%), XX male syndrome (2/23; 8.7%), 45,X/46X, i(Yp)(1/23; 4.4%) and 45,XY, t(9;22) (1/23;4.4%). Y-chromosome microdeletion in the AZFb and AZFc regions were detected in 7/266 cases (2.6%). Testicular biopsy was carried out in 31 azoospermic patients, of whom five men had Sertoli-cell only syndrome, while 26 patients had spermatogenic arrest. In conclusion, this study showed that the frequency of both chromosomal anomalies and Y microdeletions were found in 10.4% of the infertile men. The potential risk of transmitting these genetic disorders to offspring provides a rationale for screening infertile men prior to ICSI.

Iodine status among pregnant women in Kuwait.

UNLABELLED: Up to now, little has been known about iodine intake and the prevalence of iodine deficiency (ID), if any, in Kuwait. Urinary iodine excretion (UIE) and changes in thyroid function during pregnancy were thus evaluated. METHODS: Urinary iodide level was measured in random urine samples collected from 326 pregnant women at different gestational trimesters. Blood samples were drawn for free T4 (FT4) and TSH level determination. RESULTS: Median UIE levels fall within the normal range during all gestational trimesters i.e. >100 microg/l. However, if the new suggested recommendation for pregnant women <140 microg/l, is applied, median UIE values during trimesters 2 and 3 indicate ID. Mean serum TSH levels increased between trimesters 1 and 3 (p<0.05), whereas serum FT4 decreased between first and second trimesters (p<0.05), and this reduction continued at the third trimester. Furthermore, an increase in TSH levels for subjects with mild and moderate ID (Mi and Mo, respectively) were noticed (p<0.05) during the second trimester. However, FT4 levels dropped in subjects with Mi and Mo ID during the first trimester (p<0.05). In conclusion, these results suggest that 56.8% of pregnant women had median UIE level <145 microg/l, associated with high TSH and low FT4 levels. CONCLUSION: Data obtained may indicate insufficient iodine intake among pregnant women in Kuwait.

Transport of thyroid hormones to target tissues.

Endemic iodine deficiency is associated with maternal hypothyroxinemia and a relatively high incidence of neurological disorders in the offspring. The previous assumption that the placenta is impermeable to maternal thyroid hormone, has resulted in the erroneous suggestion that iodine per se has an essential role in brain development. Furthermore, the observed factorial rise in thyroxine-binding globulin (TBG) in pregnancy has often been misinterpreted as preventing thyroid hormone loss to either the fetal compartment or excretory systems. However, physiochemical analysis of the role of specific binding proteins in hormone delivery, combined with epidemiological evidence and evolutionary considerations has led us to postulate that a) maternal thyroxine (T4) is transported to the fetus, and is of crucial importance in early fetal development, and b) TBG forms part of a control system specifically designed to maintain at an optimal level the T4 environment to which the developing fetus is exposed. Placental transfer of maternal T4 in a variety of mammalian species (including humans) is now well established. Further experimental studies in rats have shown that perturbation of the intrauterine thyroid hormone environment during critical phases of brain development results in a spectrum of biochemical dysgenesis. For example, in fetal brains deriving from hypothyroxinemic (Tx) rat dams, severe disruption of phosphate metabolism is observed and the ontogenesis of two enzyme activities associated with growth control, protein kinase C and ornithine decarboxylase, are compromised. Development of brain function is also impaired, as evidenced by the dysgenesis of certain neurotransmitter metabolic activities (choline acetyltransferase and DOPA decarboxylase).(ABSTRACT TRUNCATED AT 250 WORDS)

Perturbation of thyroid hormone homeostasis in the adult and brain function.

Although a critical role of thyroid hormones in mammalian brain development is well established and extensively documented, the adult CNS is often thought to be a thyroid hormone-insensitive organ. The presence in the adult brain of thyroid hormone, along with high levels of nuclear T3 receptors and the strict regulation of intracerebral T3 levels, coupled with overt psychomotor and cognitive dysfunctions in adult-onset dysthyroidism, casts doubt upon this assumption. We have therefore investigated the influence of thyroid hormones on the biochemistry, metabolism and molecular biology of adult rat brain regions and confluent neurons and astrocytes in culture. Our results and those in the literature show that brain nuclear T3 receptor and angiotensinogen mRNA levels and 5'D-II activity are dependent upon normal thyroid hormone concentrations. Several subfractions of cell signalling proteins (G protein alpha subunits) are compromised in hypo- and hyperthyroidism and the activities of protein kinases A and C are up-regulated in the hypothyroid state in a brain region-specific manner. The activities of acid phosphatase and aryl sulphatase A are compromised in the brain of hypothyroid rats, indicating a degree of lysosomal dysfunction, and several neurotransmitter metabolic enzymes and receptor systems are also affected. Metabolic experiments indicate that glutamate and acetate metabolism are compromised in the hypothyroid state, although glucose metabolism remains normal. Primary cultures of confluent neurons and astrocytes also strongly indicate a critical role for thyroid hormones in the control of amino acid uptake, protein synthesis, glycoprotein synthesis and 2-deoxyglucose uptake, in a cell-specific manner.(ABSTRACT TRUNCATED AT 250 WORDS)