Exosomes derived from umbilical cord mesenchymal stem cells ameliorate male infertility caused by busulfan in vivo and in vitro.

Environmental pollution has emerged as a global concern due to its detrimental effects on human health. One of the critical aspects of this concern is the impact of environmental pollution on sperm quality in males. Male factor infertility accounts for approximately 40%- 50% of all infertility cases. Nonobstructive azoospermia (NOA) is the most severe type of male infertility. Human umbilical cord mesenchymal stem cell (hUCMSC) exosomes enhance proliferation and migration, playing crucial roles in tissue and organ injury repair. However, whether hUCMSC exosomes impacting on NOA caused by chemotherapeutic agents remains unknown. This study aimed to explore the functional restoration and mechanism of hUCMSC exosomes on busulfan-induced injury in GC-1 spg cells and ICR mouse testes. Our results revealed that hUCMSC exosomes effectively promoted the proliferation and migration of busulfan-treated GC-1 spg cells. Additionally, oxidative stress and apoptosis were significantly reduced when hUCMSC exosomes were treated. Furthermore, the injection of hUCMSC exosomes into the testes of ICR mice treated with busulfan upregulated the expression of mouse germ cell-specific genes, such as vasa, miwi, Stra8 and Dazl. Moreover, the expression of cellular junction- and cytoskeleton-related genes, including connexin 43, ICAM-1, ß-catenin and androgen receptor (AR), was increased in the testicular tissues treated with exosomes. Western blot analysis demonstrated significant downregulation of apoptosis-associated proteins, such as bax and caspase-3, and upregulation of bcl-2 in the mouse testicular tissues injected with hUCMSC exosomes. Further, the spermatogenesis in the experimental group of mice injected with exosomes showed partial restoration of spermatogenesis compared to the busulfan-treated group. Collectively, these findings provide evidence for the potential clinical applications of hUCMSC exosomes in cell repair and open up new avenues for the clinical treatment of NOA.

Busulfan administration replicated the characteristics of the epididymal initial segment observed in mice lacking testis-epididymis lumicrine signaling.

The physiological functions of the mammalian epididymis are typically regulated by the testes. In addition to sex steroids secreted by testicular Leydig cells, which act on the epididymis in an endocrine manner, there is a non-sex-steroidal signaling pathway known as the lumicrine pathway. This lumicrine signaling pathway involves ligand proteins secreted from germ cells within the testicular seminiferous tubules traversing the male reproductive tract, which induce epithelial differentiation in the epididymis. These findings prompted an inquiry into whether treatments influencing testis physiology can disrupt epididymal function by interfering with testis-epididymis communication. Busulfan, an alkylating agent commonly used to deplete testicular germ cells in reproductive biology, has not been sufficiently explored because of its effects on the epididymis. This study investigated the effects of busulfan administration on the proximal epididymis using histological and transcriptomic analyses. Notably, busulfan, as opposed to the vehicle dimethyl sulfoxide (DMSO), altered the morphology of the initial segment of the epididymis, leading to a reduction in the cell height of the luminal epithelium. RNA sequencing identified 185 significantly downregulated genes in the proximal epididymis of busulfan-administered mice compared to DMSO-administered mice. Comparative transcriptome analyses revealed similarities between the epididymal transcriptome of busulfan-administered mice and lumicrine-deficient mice, such as efferent-duct-ligated W/Wv and Nell2-/- mice. However, this differed from that of bilaterally orchidectomized mice, in which both the endocrine and lumicrine signaling pathways were simultaneously ablated. Collectively, these results suggested that the harmful effects of busulfan on the proximal epididymis are secondary consequences of the ablation of testis-epididymis lumicrine signaling.

Omega-3 polyunsaturated fatty acids and its metabolite 12-HEPE rescue busulfan disrupted spermatogenesis via target to GPR120.

Busulfan is an antineoplastic, which is always accompanied with the abnormal of spermatogonia self-renewal and differentiation. It has been demonstrated that the omega-3 polyunsaturated fatty acids (PUFAs) benefits mature spermatozoa. However, whether omega-3 can protect endogenous spermatogonia and the detailed mechanisms are still unclear. Evaluate of spermatogenesis function (in vivo) were examined by histopathological analysis, immunofluorescence staining, and western blotting. The levels of lipid metabolites in testicular tissue were determined via liquid chromatography. We investigated the effect of lipid metabolites on Sertoli cells provided paracrine factors to regulate spermatogonia proliferation and differentiation using co-culture system. In our study, we showed that omega-3 PUFAs significantly improved the process of sperm production and elevated the quantity of both undifferentiated Lin28+ spermatogonia and differentiated c-kit+ spermatogonia in a mouse model where spermatogenic function was disrupted by busulfan. Mass spectrometry revealed an increase in the levels of several omega-3 metabolites in the testes of mice fed with omega-3 PUFAs. The eicosapentaenoic acid metabolite 12-hydroxyeicosapentaenoic acid (12-HEPE) up-regulated bone morphogenic protein 4 (BMP4) expression through GPR120-ERK1/2 pathway activation in Sertoli cells and restored spermatogonia proliferation and differentiation. Our study provides evidence that omega-3 PUFAs metabolite 12-HEPE effectively protects spermatogonia and reveals that GPR120 might be a tractable pharmacological target for fertility in men received chemotherapy or severe spermatogenesis dysfunction.

Busulfan induces steatosis in HepaRG cells but not in primary human hepatocytes: Possible explanations and implication for the prediction of drug-induced liver injury.

BACKGROUND: The antineoplastic drug busulfan can induce different hepatic lesions including cholestasis and sinusoidal obstruction syndrome. However, hepatic steatosis has never been reported in patients. OBJECTIVES: This study aimed to determine whether busulfan could induce steatosis in primary human hepatocytes (PHH) and differentiated HepaRG cells. METHODS: Neutral lipids were determined in PHH and HepaRG cells. Mechanistic investigations were performed in HepaRG cells by measuring metabolic fluxes linked to lipid homeostasis, reduced glutathione (GSH) levels, and expression of genes involved in lipid metabolism and endoplasmic reticulum (ER) stress. Analysis of two previous transcriptomic datasets was carried out. RESULTS: Busulfan induced lipid accumulation in HepaRG cells but not in six different batches of PHH. In HepaRG cells, busulfan impaired VLDL secretion, increased fatty acid uptake, and induced ER stress. Transcriptomic data analysis and decreased GSH levels suggested that busulfan-induced steatosis might be linked to the high expression of glutathione S-transferase (GST) isoenzyme A1, which is responsible for the formation of the hepatotoxic sulfonium cation conjugate. In keeping with this, the GST inhibitor ethacrynic acid and the chemical chaperone tauroursodeoxycholic acid alleviated busulfan-induced lipid accumulation in HepaRG cells supporting the role of the sulfonium cation conjugate and ER stress in steatosis. CONCLUSION: While the HepaRG cell line is an invaluable tool for pharmacotoxicological studies, it might not be always an appropriate model to predict and mechanistically investigate drug-induced liver injury. Hence, we recommend carrying out toxicological investigations in both HepaRG cells and PHH to avoid drawing wrong conclusions on the potential hepatotoxicity of drugs and other xenobiotics.

WIN18,446 enhances spermatogonial stem cell homing and fertility after germ cell transplantation by increasing blood-testis barrier permeability.

Spermatogonial stem cells (SSCs) possess a unique ability to recolonize the seminiferous tubules. Upon microinjection into the adluminal compartment of the seminiferous tubules, SSCs transmigrate through the blood-testis barrier (BTB) to the basal compartment of the tubule and reinitiate spermatogenesis. It was recently discovered that inhibiting retinoic acid signaling with WIN18,446 enhances SSC colonization by transiently suppressing spermatogonia differentiation, thereby promoting fertility restoration. In this study, we report that WIN18,446 increases SSC colonization by disrupting the BTB. WIN18,446 altered the expression patterns of tight junction proteins (TJPs) and disrupted the BTB in busulfan-treated mice. WIN18,446 upregulated the expression of FGF2, one of the self-renewal factors for SSCs. While WIN18,446 enhanced SSC colonization in busulfan-treated wild-type mice, it did not increase colonization levels in busulfan-treated Cldn11-deficient mice, which lack the BTB, indicating that the enhancement of SSC colonization in wild-type testes depended on the loss of the BTB. Serial transplantation analysis revealed impaired self-renewal caused by WIN18,446, indicating that WIN18,446-mediated inhibition of retinoic acid signaling impaired SSC self-renewal. Strikingly, WIN18,446 administration resulted in the death of 45% of busulfan-treated recipient mice. These findings suggest that TJP modulation is the primary mechanism behind enhanced SSC homing by WIN18,446 and raise concerns regarding the use of WIN18,446 for human SSC transplantation.

The impact of busulfan on the testicular structure in prepubertal rats: A histological, ultrastructural and immunohistochemical study.

Busulfan is a widely used cancer chemotherapeutic agent. Temporary or permanent sterility in male patients is one of the most common side effects of this drug. The present study was performed to evaluate the changes in the microscopic structure of the testes of prepubertal rats, as well as the changes in PCNA and caspase-3 immune expression, at different durations after busulfan administration. The rats were 5 weeks old and were divided into two main groups. Control group and busulfan treated group. Busulfan treated group received a single dose of busulfan (40 mg/kg), then animals were subdivided to three subgroups; IIa, IIb, IIc which were sacrificed after four, ten and twenty weeks, respectively, from the beginning of the experiment. Light and electron microscopic studies were done. Serum testosterone level and relative testes weight were assessed. Immunohistochemical staining for anti-proliferating cell nuclear antigen (PCNA) and anti-caspase-3 antigen was also done. Morphometric and statistical studies were carried out. Group II revealed histological and ultrastructural degenerative changes including congested blood vessels and degenerated spermatogenic epithelium, Sertoli cells, and Leydig cells. These changes were more evident after 10 weeks of busulfan administration and were accompanied by absence of mature sperms in the lumen of seminiferous tubules. These changes were associated with a significant reduction in relative testes weight, testosterone level, germinal epithelial height and seminiferous tubule diameter. Moreover, PCNA and caspase-3 immune expression was significantly altered in busulfan treated group. Mild improvement in testicular structure was observed 20 weeks after busulfan treatment.

Pre-existing anti-factor VIII immunity alters therapeutic platelet-targeted factor VIII engraftment following busulfan conditioning through cytotoxic CD8 T cells.

BACKGROUND: We previously demonstrated that busulfan preconditioning enabled sustained therapeutic platelet-derived factor VIII (FVIII) expression in naïve FVIIInull mice transplanted with 2bF8-transduced Sca-1+ cells. However, in mice with pre-existing inhibitors, platelet-FVIII expression was lost. OBJECTIVE: In this study, we aimed to describe the mechanism of this platelet-FVIII loss. METHODS: We monitored platelet-FVIII expression in FVIIInull mice that were immunized with rhFVIII to induce inhibitors and subsequently conditioned with busulfan before whole bone marrow transplantation or Sca-1+ hematopoietic stem cell transplantation (HSCT) from 2bF8 transgenic (2bF8Tg) mice. Busulfan with or without antithymocyte globulin or anti-CD8 antibody was employed before 2bF8Tg HSCT. Interferon gamma-ELISpot assay was used to assess which subset of cells was the target in platelet-FVIII loss. B-cell-deficient homozygous mutant mice were used to determine whether platelet-FVIII loss in FVIII-primed mice was mediated by antibody-dependent cellular cytotoxicity. RESULTS: Platelet-FVIII expression was sustained in 2bF8Tg bone marrow transplantation but not in 2bF8Tg HSCT recipients. CD8 T-cell depletion in addition to busulfan preconditioning restored platelet-FVIII expression in 2bF8Tg-HSCT recipients. ELISpot analyses showed that FVIII-primed CD8 T cells were efficiently restimulated by 2bF8Tg-Sca-1+ cells and secreted interferon gamma, but were not stimulated by 2bF8Tg platelets/megakaryocytes, suggesting that 2bF8Tg-Sca-1+ cells are targets for FVIII-primed CD8 T cells. When 2bF8Tg-Sca-1+ cells were transplanted into FVIII-primed homozygous mutant mice preconditioned with busulfan, no FVIII expression was detected, suggesting that antibody-dependent cellular cytotoxicity was not the mechanism of platelet-FVIII loss in FVIII-primed mice. CONCLUSION: Pre-existng immunity can alter the engraftment of 2bF8Tg-Sca-1+ cells through the cytotoxic CD8 T-cell-mediated pathway. Sufficient eradication of FVIII-primed CD8 T cells is critical for the success of platelet gene therapy in hemophilia A with inhibitors.

Ellagic acid effects on testis, sex hormones, oxidative stress, and apoptosis in the relative sterility rat model following busulfan administration.

BACKGROUND: Busulfan is an antineoplastic medication that is broadly utilized for cancer treatment. It affects the testicular function and leads to sterility. The present study aimed to evaluate the effects of ellagic acid on testicular tissue changes, sexual hormones, antioxidant defense system, and caspase-9 and Bcl2 gene expression in the busulfan-induced relative sterile rat model. METHODS: This is an interventional-experimental animal study that was performed on 65 Adult male rats; they were randomly divided into five groups including control (1 ml of 0.9% normal saline), ellagic acid (50 mg/kg); busulfan (10 mg/kg); and busulfan plus ellagic acid (10 mg/kg and 50 mg/kg). At the end of the experiment, blood samples were collected, and plasma levels of sex hormones, antioxidant system, apoptosis-related genes, and testis histology were assessed. RESULTS: Busulfan reduced the levels of serum testosterone, total antioxidant capacity, gene expression of Bcl2, testicular volume, seminiferous tubule, germinal epithelium, interstitial tissue volume, and the number of spermatogonia, spermatocyte, round spermatid, elongated spermatid, Sertoli cells and Leydig cells (p < 0.05). Busulfan administration resulted in a significant increase (p < 0.05) in the level of LH, FSH, malondialdehyde, and caspase 9. Busulfan + ellagic acid (50 mg/kg) showed higher serum levels of testosterone, gene expression of Bcl-2 and antioxidant markers, and lower LH, FSH levels, and gene expression of caspase 9 compared to the Busulfan-treated rats (p < 0.05). Stereological parameters were also ameliorated in the group treated with Busulfan+ 50 mg/kg ellagic acid (p < 0.05). CONCLUSION: In conclusion, the consumption of ellagic acid may have beneficial effects on the antioxidant defense system, sexual hormone abnormality, and testicular tissue damage induced by busulfan.

Identification of a Crosstalk among TGR5, GLIS2, and TP53 Signaling Pathways in the Control of Undifferentiated Germ Cell Homeostasis and Chemoresistance.

Spermatogonial stem cells regenerate and maintain spermatogenesis throughout life, making testis a good model for studying stem cell biology. The effects of chemotherapy on fertility have been well-documented previously. This study investigates how busulfan, an alkylating agent that is often used for chemotherapeutic purposes, affects male fertility. Specifically, the role of the TGR5 pathway is investigated on spermatogonia homeostasis using in vivo, in vitro, and pharmacological methods. In vivo studies are performed using wild-type and Tgr5-deficient mouse models. The results clearly show that Tgr5 deficiency can facilitate restoration of the spermatogonia homeostasis and allow faster resurgence of germ cell lineage after exposure to busulfan. TGR5 modulates the expression of key genes of undifferentiated spermatogonia such as Gfra1 and Fgfr2. At the molecular level, the present data highlight molecular mechanisms underlying the interactions among the TGR5, GLIS2, and TP53 pathways in spermatogonia associated with germ cell apoptosis following busulfan exposure. This study makes a significant contribution to the literature because it shows that TGR5 plays key role on undifferentiated germ cell homeostasis and that modulating the TGR5 signaling pathway could be used as a potential therapeutic tool for fertility disorders.

Kolaviron, a flavonoid-rich extract ameliorates busulfan-induced chemo-brain and testicular damage in male rats through inhibition of oxidative stress, inflammatory, and apoptotic pathways.

Previous reports revealed that increased oxidative stress with up-regulated inflammatory proteins and apoptotic factors have serious implications in busulfan-induced chemo-brain and testicular damages. Hence, we investigated the potential reversal effects of kolaviron (KV), a neuro-active extract rich in flavonoids with proven anti-oxido-inflammatory and anti-apoptotic properties, on busulfan-induced oxidative damage, inflammatory proteins, and apoptosis in the brains and testes of male rats. In the treatment-regimen, animals in groups 1 and 2 had saline (10 ml/kg/p.o./day) and dimethyl sulfoxide (DMSO; 10 ml/kg/p.o./day), group 3 received KV extract (200 mg/kg/p.o./day), group 4 was given busulfan (50 mg/kg/p.o./day) and animals in group 5 were pretreated with busulfan (50 mg/kg/p.o./day) successively for 56 days in addition to KV extract (200 mg/kg/p.o./day) from days 29-56. Non-spatial memory function was valuated with a novel-object recognition memory test. Thereafter, testicular and brain oxidative/antioxidant status, proinflammatory- and apoptotic-related proteins, testicular enzymatic markers were evaluated respectively. Kolaviron extract improved cognitive function by increasing exploration of novel-object of busulfan-treated rats. Kolaviron extract reversed busulfan-mediated increased malondialdehyde, 8-hydroxy-2'-deoxyguanosine, and decreased superoxide dismutase, catalase, glutathione, and glutathione-peroxidase in brains and testes as well as the testicular enzyme markers. Increased brain and testicular weights, and TNF-α, IL-1ß, and NF-κß productions due to busulfan administration were also reduced by the extract. The reduced testicular B-cell lymphoma-2, sperm mitochondrial cytochrome-C, and membrane potential, increased DNA fragmentation, caspases -3 and -9 levels were also profoundly reversed by KV. Additionally, KV extract ameliorated busulfan-induced testicular histopathological changes in rats. Conclusively, KV extract reverses busulfan-induced neuroendopathobiological derangements via oxidative stress inhibition, down-regulation of inflammatory and apoptotic mediators in rats' brains and testes. PRACTICAL APPLICATIONS: Busulfan is an orally effective chemotherapy drug widely used for cancer treatment. It has been reported that chronic usage of busulfan increases the tendency for carcinogenic and teratogenic activities with severe side effects on the functions of the gonads and other body organs such as brain, popularly regarded as chemo-brain. When taken over a prolonged period of time, busulfan causes sterility in animals and destroyed spermatogonial stem cells along with the seminiferous tubules and sperm morphology of animals as well as memory impairments. The findings from the study revealed that KV extract prevent busulfan-induced cognitive and testicular impairments following kolaviron supplementation. Thus, the findings from this scientific investigation suggest that KV extract could improve the quality of reproductive life and cognitive functions of male patients during busulfan chemotherapy, particularly during prolonged therapy.

[Therapeutic effect of Heirong Kidney-Tonifying Granule on busulfan-induced dyszoospermia in model mice].

OBJECTIVE: To explore the therapeutic effect of Heirong Kidney-Tonifying Granule (HKTG) on busulfan-induced dyszoospermia in mice, and its mechanism in regulating testicular spermatogenesis. METHODS: Forty-eight male mice were randomly divided into six groups of an equal number: blank control (BC), negative control (NC), HKTG-1, HKTG-2, HKTG-3 and HKTG-4. The model of dyszoospermia was established in the latter five groups by intraperitoneal injection of busulfan at 40 mg/kg and, 30 days after modeling, the mice in the BC and NC groups were given gavage of normal saline, and those in the latter four groups treated with HKTG + pilose antler at 400 mg/kg/d, HKTG + pilose antler at 800 mg/kg/d, HKTG + black ants at 400 mg/kg/d and HKTG + black ants at 800 mg/kg/d, respectively, all for 5 consecutive weeks. The mean body weight of the mice was recorded daily, and their testes weighed after treatment. The microstructure of the testis tissue was detected by HE staining, and the localization and expression of spermatogenesis markers in the testis were determined by immunofluorescence staining. RESULTS: The mice in the BC and NC groups showed no statistically significant difference from those in the HKTG groups in the body weight and daily body weight gain (P > 0.05). Compared with the NC mice, the animals in the HKTG-1 group exhibited significantly increased testis weight (P < 0.05), and those in the HKTG-1 and HKTG-1 groups presented a large number of germ cells in the seminiferous tubules, including deformed sperm cells in the lumen, and some seminomatogonia in the seminogenic tubules, but almost no deformed sperm cells. The expressions of the total germ cell marker gene Ddx4, spermatogonial cell marker gene Dazl, spermatic cell marker gene Sycp3 and sperm cell marker gene Tnp1 were significantly upregulated (P < 0.05) while that of the Sertoli cell marker gene Sox9 downregulated (P < 0.05) in the HKTG-1 group. The number of Sertoli cells in the HKTG-1 group was remarkably reduced (P<0.05), corresponding to the increased number of germ cells in the HKTG-1 group. There were no significant changes in the relative expressions of the DDX4, Dazl, Sycp3 and Tnp1 genes, nor in the number of Sertoli cells in the HKTG-3 and HKTG-4 groups. The expressions of meiosis-related genes Meioc, Stra8 and Spo11were markedly upreguated in the HKTG-1 group, indicating significantly improved spermatogenesis in the testis tissue of the mice. CONCLUSION: HKTG improves the function of spermatogenic cells and increases sperm production in the testis tissue of mice by promoting meiosis.

The protective effect of rutin against busulfan-induced testicular damage in adult rats.

Here, we studied the protective effect of rutin (RUT) against testicular damage caused by busulfan (BUS) in rats. Adult male Wistar rats were intraperitoneally injected with BUS (4 mg/kg body weight at day 7 and 14), and then treated with RUT (30 mg/kg body weight) by gavage thrice weekly for 60 days. The results showed that BUS-induced increase in 3ß-hydroxysteroid dehydrogenase (3ß-HSD) was significantly decreased by RUT, whereas 17ß-HSD activity and plasma testosterone concentration remained unaffected (p > 0.05). It was also observed that RUT inhibited BUS-induced increase in nitrite concentrations and myeloperoxidase enzyme activities in the plasma and testes (p < 0.05). Similarly, BUS-induced decrease in glutathione and increase in malondialdehyde concentrations in the testes were significantly normalized to control values by RUT. Finally, RUT administration showed some tendency to improve the architecture of the seminiferous epithelium of the rat's testes after BUS treatment. Overall, RUT inhibited BUS-induced oxidative damage and inflammation in the testis of an experimental rat model.

Fluted pumpkin seeds protect against busulfan-induced oxidative stress and testicular injuries in adult mice.

Fluted pumpkin is traditionally claimed to improve fertility health of male adult subjects. This study evaluated the adjuvant protective potential of fluted pumpkin seeds (FPS) extract on the deleterious effects of busulfan on the testes. Tubular germ cell depletion was induced in the testis of mice by i.p. administration of busulfan (15 mg/kg body wt. two injections, seven days apart) and the effect of ethanolic extract of FPS (200 mg/kg body wt.) was investigated after 40 days of oral administration. Busulfan caused extensive damage to the seminiferous epithelium, decreased Johnsen's score index for spermatogenesis and number of Leydig cells (p < 0.05) in the interstitial areas. Co-treatment with FPS improves the testicular cyto-architecture and re-population of the seminiferous tubules with spermatogonia, spermatocytes and spermatids (p < 0.05). Interestingly, administration of FPS increases Leydig cells count in the interstitial areas (p < 0.05) and plasma testosterone but not follicle stimulating hormone and luteinizing hormone concentrations. This study established that FPS prevented oxidative damage and increased the number of spermatogonia, spermatids, spermatocytes and Leydig cells thereby restoring spermatogenesis in busulfan-treated mice. Thus FPS is a potential complementary adjuvant during chemotherapy-induced tubular germ cell depletion.

Gallic acid ameliorates busulfan-induced testicular toxicity and damage in mature rats.

Here, we studied the protective effect of gallic acid (GAL) as a potent anti-oxidant and anti-inflammatory agent against damage caused by busulfan (BUS) in the testes of adult rats. The adult Wistar rats were assigned as control, BUS: was intraperitoneally (i.p.) treated with busulfan (15 mg/kg, day 7 and 14), GAL + BUS: was co-treated with busulfan (i.p., 15 mg/kg, day 7 and 14) and orally treated (per os) with gallic acid (60 days, 20 mg/kg) and GAL: was treated with gallic acid (per os, 60 days, 20 mg/kg). The results showed that GAL co-treatment increased the numbers of spermatogonia (Type A and B), spermatocytes (primary and secondary) and round spermatids, along with the tubular diameter, epithelial height and gonado-somatic index. In addition, BUS-induced increase in 3ß-hydroxysteroid dehydrogenase and γ-glutamyl transpeptidase activities were inhibited on GAL co-treatment. Similarly, BUS-induced decrease in gluthathione concentration, catalase and superoxide dismutase activities along with increase in myeloperoxidase activity and malondialdehyde concentration were significantly normalized to control values on GAL co-treatment. Busulfan-induced elimination of tubular germ cells was completely prevented by GAL. Overall, GAL may inhibit BUS-mediated spermatogenesis arrest via decreasing inflammatory-mediated oxidative stress in a rat experimental model.

Is Busulfan Clearance Different in Patients With Sickle Cell Disease? Let's Clear Up That Case With Some Controls.

In busulfan-based conditioning regimen for hematopoietic stem cell transplantation in children, accurate a priori determination of the first dose is important because of its narrow therapeutic window. Sickle cell disease (SCD) influences pharmacokinetics of the commonly used drugs by affecting organs responsible for drug metabolism and elimination. This pharmacokinetics study assesses the influence of SCD on the metabolic pathway of busulfan that is mainly metabolized in the liver. In this retrospective cross-sectional case-control study, 16 patients with SCD were matched to 50 patients without SCD on known busulfan clearance's covariates (glutathione-S-transferase alpha1 polymorphisms, age, weight). Clearance of the first dose of busulfan was not significantly different independently of genetic or anthropometric factors in patients with or without SCD.

The effects of ozone and melatonin on busulfan-induced testicular damage in mice.

OBJECTIVE: Busulfan is one of the most common chemotherapeutic drugs and has the ability to induce apoptosis in testicular germ cells, which leads to infertility. In this study, the effects of ozone therapy and melatonin were evaluated on testicular disorders induced by busulfan. METHODS: In this study, we divided 24 male mice into four groups: control group, groups treated with busulfan, busulfan/melatonin, and busulfan/ozone. At the end of a 35-day period, blood samples were taken from the mice and their testosterone levels were measured. Both of the mice's testes were removed and weighed, afterwards, each one of them was used for evaluation of morphology by Johnson's score, as well as for measuring the diameter and thickness of seminiferous tubules. The other testis was homogenized for measuring Malondialdehyde (MDA) and antioxidant status using Catalase (CAT), Super Oxide Dismutase (SOD), and Total Antioxidant Capacity (TAC) levels. Epididymis spermatozoa were also used to evaluate motility, morphology, and sperm count. RESULTS: Busulfan significantly reduced the testis quality (weight, sperm parameters, testosterone, CAT, SOD, and TAC levels) and increased MDA and destruction of seminiferous tubules compared to the control group. Ozone and melatonin treatments significantly increased testis quality, sperm parameters, MDA, and antioxidant status, but they did not affect the TAC level. CONCLUSIONS: This study showed that similar to melatonin, ozone can reduce the effect of busulfan toxicity on mice testis. However, further studies are needed to understand the precise mechanism of ozone function on testis.

Busulfan clearance does not predict the development of hepatic veno-occlusive disease in patients undergoing hematopoietic stem cell transplantation.

Hepatic veno-occlusive disease (VOD) is a life-threatening complication following hematopoietic stem cell transplant (HSCT). Busulfan has a narrow therapeutic index and its concentration was found to correlate with VOD. Our primary objective was to assess the association between busulfan clearance and VOD in HSCT patients. In this retrospective analysis, we included patients who received their HSCT between 2003 and 2014 and followed at Sultan Qaboos University Hospital. All patients who received dose-targeted busulfan-containing conditioning were included. Target steady-state concentration (Css) was 800-900 ng/ml. VOD was assessed using modified Seattle criteria. The impact of busulfan clearance on VOD was analyzed using univariable logistic regression model. Seventy-three patients were included with a mean age of 15 years. Of those, 47% were transplanted for hematological malignancies and 53% for inherited hemoglobinopathies. Target Css was achieved in 85% of patients. The rate of VOD was 17%. There was no significant impact of busulfan clearance (p = 0.919) or area-under-the-concentration-time-curve (p = 0.275) on VOD. Targeting busulfan Css into narrow therapeutic range may have accounted for the findings. The risk of VOD might be related to other factors such as the genetic background, and more studies are required to investigate these factors.

Is Salivary Busulfan the Cause of Oral Mucositis and the Changes in Salivary Antioxidant Enzymes After Hematopoietic Cell Transplantation?

BACKGROUND: To determine whether the busulfan (Bu) present in saliva during hematopoietic cell transplantation (HCT) conditioning correlates with oral mucositis and the changes in salivary antioxidant enzymes. METHODS: Bu levels in the plasma and saliva of 19 patients who received HCTs were quantified. Salivary flow and salivary superoxide dismutase and catalase activities were measured during HCT. For the toxicity analysis of salivary Bu, an in vitro assay was conducted by exposing human keratinocytes to artificial saliva containing Bu. RESULTS: Plasma and salivary Bu concentrations were very similar (rho = 0.92, P < 0.001). Salivary Bu concentration correlated with the degree of oral mucositis severity (rho = 0.391, P = 0.029) and was inversely proportional to salivary superoxide dismutase and catalase activities (rho = -0.458, P = 0.036; rho = -0.424, P = 0.043, respectively). Cells exposed to Bu-containing saliva had fewer viable cells (P < 0.01) and more apoptotic cells (P = 0.001) than those exposed to non-Bu-containing saliva. CONCLUSIONS: Bu found in saliva during HCT conditioning was correlated with severe oral mucositis and the reduction in salivary antioxidative activity. Furthermore, Bu can be toxic to keratinocytes.

Extrapolation of Drug Clearance in Children ≤ 2 Years of Age from Empirical Models Using Data from Children (> 2 Years) and Adults.

BACKGROUND: The application of modeling and simulation approaches in clinical pharmacology studies has gained momentum over the last 20 years. OBJECTIVES: The objective of this study was to develop six empirical models from clearance data obtained from children aged > 2 years and adults to evaluate the suitability of the models to predict drug clearance in children aged ≤ 2 years (preterm, term, and infants). METHODS: Ten drugs were included in this study and administered intravenously: alfentanil, amikacin, busulfan, cefetamet, meperidine, oxycodone, propofol, sufentanil, theophylline, and tobramycin. These drugs were selected according to the availability of individual subjects' weight, age, and clearance data (concentration-time data for these drugs were not available to the author). The chosen drugs are eliminated by extensive metabolism by either the renal route or both the renal and hepatic routes. The six empirical models were (1) age and body weight-dependent sigmoidal maximum possible effect (Emax) maturation model, (2) body weight-dependent sigmoidal Emax model, (3) uridine 5'-diphospho [body weight-dependent allometric exponent model (BDE)], (4) age-dependent allometric exponent model (ADE), (5) a semi-physiological model, and (6) an allometric model developed from children aged > 2 years to adults. The model-predicted clearance values were compared with observed clearance values in an individual child. In this analysis, a prediction error of ≤ 50% for mean or individual clearance values was considered acceptable. RESULTS: Across all age groups and the ten drugs, data for 282 children were compared between observed and model-predicted clearance values. The validation data consisted of 33 observations (sum of different age groups for ten drugs). Only three of the six models (body weight-dependent sigmoidal Emax model, ADE, and semi-physiological model) provided reasonably accurate predictions of clearance (> 80% observation with ≤ 50% prediction error) in children aged ≤ 2 years. In most instances, individual predicted clearance values were erratic (as indicated by % error) and were not in agreement with the observed clearance values. CONCLUSIONS: The study indicated that simple empirical models can provide more accurate results than complex empirical models.

In Vitro Study of the Enzymatic and Nonenzymatic Conjugation of Treosulfan with Glutathione.

BACKGROUND AND OBJECTIVES: Treosulfan (dihydroxybusulfan), licensed for the treatment of ovarian carcinoma, is investigated in clinical trials as a myeloablative agent for conditioning prior to hematopoietic stem cell transplantation. Clinical experience shows that treosulfan exhibits lower organ toxicity than busulfan, including hepatotoxicity. Elimination of busulfan primarily via enzymatic conjugation with glutathione (GSH) in the liver is considered to be the main cause of the drug's hepatotoxicity and interpatient clearance variability. It is believed that treosulfan undergoes no hepatic metabolism but empirical evidence is lacking. The aim of this kinetic study was to verify if treosulfan is capable of conjugating with GSH. METHODS: Treosulfan (200 µM) was incubated at pH 7.2 and 37 °C with 5 mM GSH in the presence or absence of human liver cytosol, the main store of glutathione S-transferase in the body. Concentrations of treosulfan were determined using liquid chromatography-tandem mass spectrometry and then subjected to kinetic analysis. RESULTS: The decay of treosulfan in the solution followed a one-exponential model in the presence of either GSH or liver cytosol and GSH. The first-order reaction rate constants (0.25 h-1) did not differ statistically from those found for treosulfan conversion in pH 7.2 buffer only. CONCLUSION: Treosulfan does not undergo either spontaneous or enzymatic conjugation with GSH at a noticeable rate. The result indicates that the clearance of treosulfan is independent of glutathione S-transferase activity, GSH stores, and co-administration of drugs utilizing the GSH metabolic pathway.