Testicular Iron Research Articles

Going Going Gonad: Assessing Iron Staining Impact on Fertility for Patients with Sickle Cell Disease

Introduction: Medical advances in the care of patients with sickle cell disease (SCD) and other hemoglobinopathies have allowed for the focus of care to shift and incorporate long-term quality of life metrics, such as fertility. Concerns for reproductive health in patients with SCD stem from the underlying disease itself as well as from medical therapies that are offered such as hydroxyurea, chronic red blood cell transfusions, and stem cell transplant (SCT). Iron deposition from chronic transfusions in other tissues is known to result in end organ damage and lifelong consequences. While little is known about iron overload and fertility, one study noted testicular iron deposition on MRI in pubertal males with transfusion-dependent beta-thalassemia; results were notable for lower sperm concentrations and a lower percentage of sperm with normal morphology, indicating that iron overload likely has an impact on fertility for patients. Iron deposition has not been studied in the pre-pubertal hemoglobinopathy population. Fertility counseling in this patient population does not often occur until patients are considering SCT as a curative therapy option, as the conditioning regimens for SCT are gonadotoxic. Without a good understanding of the impact of chronic transfusions on fertility for patients with hemoglobinopathies, it is difficult to determine the optimal time to offer fertility preservation to families. We aim to assess iron overload on testicular tissue to gain a better understanding of the impact that medical management and chronic transfusions can have on fertility for a patient with SCD. Methods: Our study is a cross-sectional evaluation of patients with SCD who underwent testicular tissue cryopreservation (TTC) as a part of a multicenter research protocol through the University of Pittsburgh Medical Center (UPMC) prior to SCT. As part of the TTC protocol, each patient provided a small piece of tissue for research, with the remaining cryopreserved for patient use. All samples were evaluated for the presence of germ cells. For this study, demographics, treatment data, imaging results, and labs pertinent to hormonal profile and iron status were obtained. All samples from patients with SCD and thalassemia will undergo additional pathology review to evaluate for the presence of germ cells and iron. At the time of this abstract, the tissue for two patients had been analyzed. Results: Banked research tissue from UPMC includes 77 patients with SCD and 21 patients with beta thalassemia major. Of the 77 SCD patient samples, 42 were found to have germ cells, 34 have not yet been analyzed and 1 had no germ cells present. Of the 21 samples from patients with beta thalassemia major, 17 were found to have germ cells, 3 were not yet analyzed and 1 had no germ cells present. To date, we have obtained pathology review on two patients, both with Hb SS genotype and were on the maximum tolerated dose of hydroxyurea prior to TTC. Patient 1 had been on hydroxyurea for 7 years and had 13 units of blood transfusions, and Patient 2 on hydroxyurea for 4 years and 6units of blood transfusions prior to TTC. Both patients were found to have normal testicular tissue histopathology with presence of germ cells and without evidence of iron on staining (Table 1). Conclusions: Based on our preliminary data it can be noted that patients without significant iron burden, based on low ferritin and a limited transfusion history may not have a significant impact on their testicular histopathology with their iron staining being negative. We will expand our patient cohort to include patients who have a severe disease course requiring more blood transfusions to determine whether this is associated with increased iron deposition in their testicular tissue and/or reduced germ cell numbers. This information will allow teams to optimize the timing of fertility discussions and possible preservation in this patient population, even outside of curative treatment.

Deoxynivalenol induces testicular ferroptosis by regulating the Nrf2/System Xc-/GPX4 axis.

Deoxynivalenol (DON) is the most common mycotoxin contaminant in food and feed. DON accumulation in food chain severely threatens human and animal health due to the toxic effects on the reproduction system. However, the underlying mechanism of DON on male reproductive dysfunction is still in debate and there is little information about whether DON triggers testicular ferroptosis. In this study, male C57BL/6 mice were divided into 4 groups and treated by oral gavage with 0, 0.5, 1.0, 2.0 mg/kg BW DON for 28 days. Firstly, we proved that male reproduction dysfunction was induced by DON through assessing testicular histopathology, serum testosterone level as well as blood-testis barrier integrity. Then, we verified ferroptosis occurred in DON-induced testicular dysfunction model through disrupting iron homeostasis, increasing lipid peroxidation and inhibiting system Xc-/Gpx4 axis. Notably, the present data showed DON reduced antioxidant capacity via blocking Nrf2 pathway to lead to the further weakness of ferroptosis resistance. Altogether, these results indicated that DON caused mice testicular ferroptosis associated with inhibiting Nrf2/System Xc-/GPx4 axis, which provided that maintaining testicular iron homeostasis and activating Nrf2 pathway may be a potential target for alleviating testicular toxicity of DON in the future.

Tetramethyl bisphenol a inhibits leydig cell function in late puberty by inducing ferroptosis

Tetramethyl bisphenol A (TMBPA) is a commonly used bisphenol analog, used as a fire retardant. However, whether it inhibits the function of Leydig cells in late puberty remains unclear. In this study, 35-day-old male Sprague-Dawley rats were gavaged with 0, 10, 100, and 200 mg/kg body weight TMBPA for 21 days. TMBPA significantly reduced serum testosterone levels at 10 mg/kg and higher doses without altering serum luteinizing hormone and follicle-stimulating hormone levels. TMBPA significantly increased serum iron concentraion while reducing the ratio of serum glutathione (GSH) and GSH/GSSG (oxidized glutathione disulfide). In addition, TMBPA significantly increased testicular iron amount at 10 mg/kg and higher doses and malondialdehyde level at 200 mg/kg. TMBPA down-regulated the expression of Leydig cell genes, including Nr5a1, Star, Scarb1, Insl3, Cyp11a1, Cyp17a1, Hsd17b3, and Hsd11b1, and their proteins. In addition, TMBPA markedly down-regulated the expression of genes in the ferroptosis pathway (Tp53, Slc7a11, Sod1, Sod2, Cat, Sqstm1, Keap1, and Hmox1). TMBPA significantly reduced the levels of ferroptosis pathway proteins (TP53, SLC7A11, GPX4, SQSTM1, KEAP1, NRF2, and HMOX1) in Leydig cells in vivo. Immature and adult Leydig cell culture in vitro also showed that TMBPA significantly reduced testosterone concentrations in the medium, which can be reversed by a ferroptosis inhibitor. After 24 h of culture in primary Leydig cells at 10 and 50 μM, TMBPA significantly induced reactive oxygen species and lowered the mitochondrial membrane potential. TMBPA also altered protein levels in the ferroptosis pathway in Leydig cells in vitro. In conclusion, TMBPA directly inhibits the activity of rat Leydig cell steroidogenic enzymes and induces the ferroptosis of Leydig cells, thereby inhibiting the testosterone synthesis of Leydig cells in the late puberty.

Alteration in iron efflux affects male sex hormone testosterone biosynthesis in a diet-induced obese rat model.

This study was motivated by clinical observations that dysmetabolic iron overload syndrome (DIOS) and an androgen deficiency are common features observed in obese adult men; however, the molecular mechanism underlying the effects of DIOS on androgen deficiency remains to be elucidated. We established a DIOS animal model by feeding Sprague-Dawley rats an iron/fat-enriched diet (50% fat plus 0.25, 1, or 2 g ferric iron per kg diet) for 12 weeks to induce iron dysfunction (indicated by decreased tissue iron efflux) in obese rats. Obese rats fed an iron/fat-enriched diet showed decreased levels of testicular total Testosterone (T) and iron exporter ferroportin but increased levels of testicular iron and hepcidin, and these effects were more evident with a >1 g ferric iron per kg diet. A western blot analysis showed that an iron/fat-enriched diet triggered testicular endoplasmic reticular (ER) stress but decreased mitochondrion biogenesis proteins (PGC1α and TFAM) and T-converting proteins (StAR, CYP11A, and 17β-HSD). TUNEL staining showed that >1 g ferric iron induced apoptosis mainly in germ cells and Leydig's cells. Uncontrolled testicular iron efflux may cause mitochondrial-ER dysfunction and affect T biosynthesis. Future study targeting the testicular hepcidin-ferroportin axis may offer a therapeutic tool to alleviate testicular iron retention and mitochondrial-ER stress in Leydig's cells.

Relationships of testicular iron and ferritin concentrations with testicular weight and sperm production in boars12

The inverse relationship of testicular size and circulating follicle-stimulating hormone (FSH) concentrations has been documented, and accompanying this relationship is the change in color of the parenchymal tissue of the testes. Large testes (300 to 400 g) are pink to light red and small testes (100 g) are dark maroon with color gradations for weights in between. It was hypothesized that this color most likely represented an iron protein. Chromatographic analysis of testicular tissue indicated that the Fe was associated primarily with ferritin, and immunohistochemistry showed that Leydig cells were the primary location of ferritin storage within the testes. Concentrations of Fe and ferritin were higher in small testes and decreased as testes weight increased (P < 0.05). As testicular Fe concentrations increased, daily sperm production (DSP) and total DSP declined (P < 0.05). Genotyping six generations of Meishan x White composite boars (n = 288) for a quantitative trait locus that is indicative of elevated FSH and small testes in boars indicated that the Meishan genotype had elevated testicular iron concentrations and darker color in conjunction with reduced total DSP (P < 0.01). It is not thought the elevated iron concentrations affect testicular weights but are probably a result of elevated FSH and FSH inducement of Fe transport. The storage of Fe in Leydig cells may provide a reservoir of Fe for easy access by Sertoli and germ cells, but still provide a degree of protection to germ cells from ionic iron.

COMPARATIVE EFFECTS OF DISULFIRAM AND DIETHYLDITHIOCARBAMATE AGAINST TESTICULAR TOXICITY IN RATS CAUSED BY ACUTE EXPOSURE TO CADMIUM

Disulfiram (DSF) and diethyldithiocarbamate (DED) were compared for their protective effects against the testicular toxicity induced by acute exposure to cadmium (Cd) in rats. Rats were injected subcutaneously with CdCl2 [26.7 mol (3 mg) Cd/kg], and 30 min later they were injected intraperitoneally with DSF (0.05-0.5 mmol/kg) or DED (0.1-1 mmol/kg). The treatment with DSF at dose levels of 0.1-0.5 mmol/kg prevented the increases in testicular lipid peroxidation and calcium (Ca) concentrations and the decreases in testicular weight that were observed at 7 d after Cd injection. DED at dosage levels of 0.2-1 mmol/kg likewise reduced Cd-induced testicular toxicity. An increase in testicular iron (Fe) concentrations at 7 d and sterility at 59 d after Cd injection were almost completely blocked by treatment with DSF or DED at the highest doses, but lower doses of DSF or DED were ineffective. These results indicated that DSF, which is metabolized to DED, had a protective effect against Cd-induced testicular toxicity nearly equivalent to DED at approximately one-half the dose.

Mechanism of testicular atrophy induced by di-n-butyl phthalate in rats. Part 5. Testicular iron depletion and levels of ferritin, haemoglobin and transferrin in the bone marrow, liver and spleen.

This study reports changes in levels of ferritin, haemoglobin and transferrin in the bone marrow, liver and spleen as an attempt to determine the causes of testicular iron depletion. A single oral dose of di-n-butyl phthalate (DBP) to male rats caused a sloughing of the germ cells (at 6 h) prior to testicular atrophy. Before the sloughing it was observed that DBP induced decreases both in the iron levels in the blood, bone marrow and testis and in haemoglobin (Hb) levels in the blood, bone marrow and spleen. Decrease in transferrin (Tf) levels was observed in the liver. Significant increases in ferritin and haemosiderin (Hs) levels were observed in the spleen and in the liver and spleen, respectively. In vitro studies where mono-n-butyl phthalate (MBP) was incubated with liver homogenates, MBP caused both the decreases in Hb and Tf-bound iron levels and increases in Hs and Hs-iron levels. The present study proposes that the mechanism of testicular atrophy by DBP might be associated with both the iron release from Hb and/or Tf in the liver and spleen and the subsequent depletion of iron in the blood and testes.

MRI in haemochromatosis: pituitary versus testicular iron deposition in five patients with hypogonadism

MRI in haemochromatosis: pituitary versus testicular iron deposition in five patients with hypogonadism

MRI in haemochromatosis: pituitary versus testicular iron deposition in five patients with hypogonadism

Haemochromatosis is a disease characterised by iron deposition in the liver and other organs. Hypogonadism is a commonly associated condition and may be either primary due to testicular lesions or secondary due to pituitary dysfunction. Hypogonadism secondary to pituitary dysfunction is more frequent and is thought to be related to iron deposition in the anterior pituitary. Increased iron content decreases signal intensity of spin-echo MRI images because T2 values are significantly shortened. Our purpose in this study was to evaluate by MRI iron deposition in the liver, testis and pituitary of 6 patients with haemochromatosis and severe hypogonadotrophic hypogonadism. Six subjects sereved as controls. There was a significant T2 shortening of the liver and pituitary i in patients with haemochromatosis compared with control patients. Therefore MRI detected iron overload in the pituitary and no iron in the testis, supporting the hypothesis of hypogonadotrophic pituitary insufficiency due to cellular damage induced by iron overload in the anterior pituitary gland.

The testicular iron shuttle: a "nurse" function of the Sertoli cells.

The techniques of cell culture and molecular biology first revealed that Sertoli cells synthesize transferrin. Accumulated biological information led to a plausible model for the role of testicular transferrin in an iron shuttle system designed to transport ferric ions around the cellular tight junctions to the germ cells inside the blood-testis barrier. Experiments done in culture and in vivo have supported many aspects of this model. A mutant mouse model that lacks the ability to synthesize transferrin is defective in spermatogenesis and may help to delineate the nature of the iron requirement by germ cells. The levels of seminal transferrin, possibly of Sertoli cell origin, are proportional to sperm production in humans and cattle and may be an effective indicator of Sertoli cell function. The testicular iron shuttle thus represents an important "nurse cell" function of the Sertoli cells.

Mechanism of testicular atrophy induced by Di-n-butyl phthalate in rats. VI. A possible origin of testicular iron depletion.

In previous studies we have described mechanisms of testicular atrophy whereby di-n-butyl phthalate (DBP) caused a sloughing of the germ cells, prior to the testicular atrophy; this sloughing might be attributed to iron depletion in the blood and the testicular interstitial cells. To determine whether the iron depletion is mediated by iron-release from hemoglobin (Hb), the effects of DBP upon erythrocytes have been studied. In the in vivo studies, it was observed that DBP induced glutathione (GSH) depletion, a decrease in GSH reductase activity and Heinz body formation in the red blood cells, and iron-release from Hb. In the in vitro studies, in which mono-n-butyl phthalate (MBP), a metabolite of DBP, was incubated with erythrocytes, Heinz bodies and iron release from Hb were observed. The present study proposes that a mechanism for the testicular atrophy induced by DBP might involve Heinz body formation, accompanied by iron release from Hb followed by depletion of iron in the blood and testes.

Mechanisms of testicular atrophy induced by Di‐n‐butyl phthalate in rats. Part 3. Changes in the activity of some enzymes in the sertoli and germ cells, and in the levels of metal ions

A single oral dose of di-n-butyl phthalate (DBP) to male rats caused a sloughing of the germ cells at 6 h, with more severe sloughing at 24 and 48 h. DBP is metabolized to mono-n-butyl phthalate (MBP), which is transported through the blood-tubular barrier into the seminiferous lumen. MBP is incorporated into the lumen at a maximum rate between 1 and 3 h after dosing with DBP. MBP caused decreases in the activities of succinate dehydrogenase in the Sertoli cells and sorbitol dehydrogenase in the germ cells, an increase in the activity of lactate dehydrogenase (LDH) in the germ cells and in the seminiferous lumen and a decrease in testicular iron levels.

Mechanism of testicular atrophy induced by Di‐n‐butyl phthalate in rats. Part 1

Repeated oral doses of di-n-butyl phthalate (DBP) to male rats caused a decrease in testicular fructose and glucose and a sloughing of the germ cells on the first day of treatment. On day 2, more severe sloughing was seen and was accompanied by decreases in testicular iron and zinc levels and increases in the level of inositol and cholesterols. The sloughing was followed by atrophy, accompanied by dissociation of the germ cells from the Sertoli cells and reduction of triglycerides, cholesterols and phospholipids containing choline and ethanolamine residues in the testis.