Hydrogen sulfide (H2S) is the third type of active endogenous gaseous signal molecule following nitric oxide (NO) and carbon monoxide (CO). In mammalians, H2S is mainly synthesized by two proteases, cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE). H2S plays an essential function of physiological regulation in vivo, and promotes penile erection by acting on the ATP-sensitive potassium channels to relax the vascular smooth muscle as well as by the synergistic effect with testosterone and NO to relax the corpus cavernosum smooth muscle (CCSM). At present, the selective phosphodiesterase type 5 (PDE5) inhibitor is mainly used for the treatment of erectile dysfunction (ED), but some ED patients fail to respond. Therefore, further studies on the mechanism of H2S regulating penile erection may provide a new way for the management of erectile dysfunction.
Cystathionine beta-Synthase ; metabolism ; Cystathionine gamma-Lyase ; metabolism ; Humans ; Hydrogen Sulfide ; Male ; Penile Erection

OBJECTIVETo investigate the role of endogenous hydrogen sulfide (H2S) in erectile dysfunction (ED) induced by androgen deficiency.

METHODSWe randomly divided 30 eight-week-old healthy male SD rats into six groups: 2-week control (A), 4-week control (B), 2-week castration (C), 4-week castration (D), 2-week castration + androgen replacement (E), and 4-week castration + androgen replacement (F), those in groups E and F subcutaneously injected with testosterone propionate (TP) at the physiological dose of 3 mg/kg per day after castration, while those in the other groups with isodose oil instead. At 2 and 4 weeks after operation, we determined the level of serum testosterone (T) , intracavernous pressure (ICP) , mean carotid arterial pressure (MAP) of the rats, measured the concentration of H2S in the plasma and corpus cavernosum tissue, and detected the expressions of cystathionine-P3-synthase (CBS) and cystathionine-gamma-lyase (CSE) by immunohistochemistry and Western blot.

RESULTSThe serum T level was significantly lower in group C ([0.63 +/- 0.15] nmol/L) than in A ( [ 16.55 +/- 4.17] nmol/L) and E ( [ 18.99 +/- 4.62] nmol/L) (P <0.05), as well as in group D ([0.70 +/-0.22] nmol/L) than in B ([15.44 +/-5.18] nmol/L) and F ([20.99 +/-6.41] nmol/L) (P <0. 05) , and so were ICP/MAP after 5 and 7 V electrical stimulation of the pelvic ganglia (P <0. 05) , H2 S concentration (P <0.05), and the expressions of CBS and CSE (P <0.05). The expressions of CBS and CSE proteins were also significantly decreased in group C as compared with D (P <0.05).

CONCLUSIONThe reduced expressions of CBS and CSE may inhibit the H2 S signaling pathway, which might be one of the mechanisms underlying androgen deficiency-induced ED in rats.

Androgens ; deficiency ; Animals ; Cystathionine beta-Synthase ; metabolism ; Cystathionine gamma-Lyase ; metabolism ; Erectile Dysfunction ; metabolism ; Hydrogen Sulfide ; metabolism ; Male ; Orchiectomy ; Penis ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the expressions of cystathionine gamma-lyase (CSE) and cystathionine beta-synthase (CBS) in the corpus cavernosum of spontaneous hypertensive rats (SHR) and their relationship with erectile dysfunction.

METHODSThis study included 10 male SHRs and 10 healthy male Wistar-Kyoto (WKY) rats as controls, all aged 12 weeks. We applied a series of electric stimuli to the major pelvic ganglions of the rats, observed changes in the ratio of intracavernosal to mean arterial blood pressure (ICP/MAP), measured the levels of serum testosterone (T) and endogenous H2S, and determined the expressions of CSE and CBS in the corpus cavernosum by Western blot and immunohistochemistry.

RESULTSNo obvious difference was found in the serum T level between the two groups. Compared with the WKY rats, the SHRs showed significant reduction in the ICP/MAP ratio, the contents of plasma H2S ([21.92 +/- 2.75] micromol/L vs [10.49 +/- 1.35] micromol/L, P < 0.05) and endogenous corpus cavernosal H2S ([87.67 +/- 2.12] nmol/mg prot vs [52.60 +/- 3.44] nmol/mg prot, P < 0.05), the level of endogenous H2S synthesis ([4.35 +/- 0.32] nmol/mg per min vs [1.14 +/- 0.07] nmol/mg per min, P < 0.05) and the expressions of CBS and CSE (P < 0.05). Immunohistochemistry showed that CSE and CBS were distributed mainly in the smooth muscle cells and vascular endothelial cells of the corpus cavernosum. The ICP/MAP ratio was highly positively correlated with the expressions of CSE (r = 0.977, P < 0.05) and CBS (r = 0.955, P < 0.05) in the corpus cavernosal tissue.

CONCLUSIONHypertension inhibits endogenous H2S synthesis by suppressing the expressions of CSE and CBS in the corpus cavernosum, which might be related with hypertension-induced reduction of erectile function.

Animals ; Cystathionine beta-Synthase ; metabolism ; Cystathionine gamma-Lyase ; metabolism ; Gene Expression Regulation ; Hydrogen Sulfide ; blood ; Hypertension ; metabolism ; Male ; Penis ; enzymology ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY

OBJECTIVETo study the expressions of cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE) in the corpus cavernosum smooth muscle of castrated rats and their roles in erectile dysfunction after castration.

METHODSWe randomly assigned 40 eight-week-old male SD rats to groups A (2-week sham-operation), B (4-week sham-operation), C (2-week castration) and D (4-week castration). We determined the level of serum testosterone (T) and the expressions of CBS and CSE in the corpus cavernosum smooth muscle of the rats after operation using immunohistochemistry and RT-PCR.

RESULTSThe T level was significantly decreased in groups C ([11.85 +/- 6.73] nmol/L) and D ([1.96 +/- 1.23] nmol/L) as compared with A ([89.65 +/- 17.13] nmol/L) and B ([106.75 +/- 19.68] nmol/L) (P < 0.05). CBS and CSE were expressed in all groups of rats, but the relative expressions of CBS and CSE mRNA were significantly lower in groups C (0.93 +/- 0.14 and 0.87 +/- 0.20) and D (0.79 +/- 0.17 and 0.71 +/- 0.12) than in A (2.13 +/- 0.65 and 1.93 +/- 0.15) and B (2.07 +/- 0.53 and 1.89 +/- 0.45) (P < 0. 05), so were the optical density values (IA) of the CBS and CSE proteins, 130.35 +/- 23.56 and 93.56 +/- 36.64 in group C and 80.29 +/- 29.65 and 58.56 +/- 19.95 in group D, as compared with 310.57 +/- 130.56 and 269.56 +/- 116.76 in group A and 349.68 +/-112.35 and 298.35 +/- 100.76 in group B (P < 0.05). The androgen level was positively correlated with the expressions of CBS and CSE in the corpus cavernosum smooth muscle of the rats.

CONCLUSIONAndrogen regulates erectile function via the expressions of CBS and CSE.

Animals ; Cystathionine beta-Synthase ; metabolism ; Cystathionine gamma-Lyase ; metabolism ; Male ; Muscle, Smooth ; enzymology ; Orchiectomy ; Penis ; enzymology ; Rats ; Rats, Sprague-Dawley ; Testosterone ; blood

Arteriosclerosis and its complications, such as heart attack and stroke, are the major causes of death in developed countries. It was believed that age, hyperlipidemia, hypertension, diabetes and smoking are common risk factors for cardiovascular disease. In addition, overwhelming clinical and epidemiological studies have identified homocysteine (Hcy) as a significant and independent risk factor for cardiovascular disease. In healthy individuals, plasma Hcy is between 5 and 10 micromol/L. One cause of severe hypehomocys- teinemia (HHcy) is the deficiency of cystathionine beta-synthase (CBS), which converts Hcy to cystathionine. CBS homozygous deficiency results in severe HHcy with Hcy levels up to 100 to 500 micromol/L. Patients with severe HHcy usually present with neurological abnormalities, premature arteriosclerosis. It has been reported that lowering plasma Hcy improved endothelial dysfunction and reduced incidence of major adverse events after percutaneous coronary intervention. The mechanisms by which Hcy induces atherosclerosis are largely unknown. Several biological mechanisms have been proposed to explain cardiovascular pathological changes associated with HHcy. These include: (1) endothelial cell damage and impaired endothelial function; (2) dysregulation of cholesterol and triglyceride biosynthesis; (3) stimulation of vascular smooth muscle cell proliferation; (4) thrombosis activation and (5) activation of monocytes. Four major biochemical mechanisms have been proposed to explain the vascular pathology of Hcy. These include: (1) autooxidation through the production of reactive oxygen species; (2) hypomethylation by forming SAH, a potent inhibitor of biological transmethylations; (3) nitrosylation by binding to nitric oxide or (4) protein homocysteinylation by incorporating into protein. In summary, our studies, as well as data from other laboratories support the concept that Hcy is causally linked to atherosclerosis, and is not merely associated with the disease. Although folic acid, vitamin B12 and B6 can lower plasma Hcy levels, the long-term effects on cardiovascular disease risk are still unknown and judgments about therapeutic benefits await the findings of ongoing clinical trials.
Animals ; Atherosclerosis ; etiology ; physiopathology ; Cystathionine beta-Synthase ; deficiency ; genetics ; Homocysteine ; metabolism ; Humans ; Hyperhomocysteinemia ; complications ; physiopathology ; Reactive Oxygen Species ; metabolism

The present study was designed to investigate the potential role of endogenous hydrogen sulfide (H2S) in chronic stress-induced colonic hypermotility. Male Wistar rats were submitted daily to 1 h of water avoidance stress (WAS) or sham WAS (SWAS) for 10 consecutive days. The total number of fecal pellets was counted at the end of each 1 h of WAS or SWAS session. Organ bath recordings were used to test the colonic motility. H₂S production of colon was determined, and immunohistochemistry and Western blot were performed on rat colonic samples to detect the distribution and expression of H₂S-producing enzymes. The results showed that i) repeated WAS increased the number of fecal pellets per hour and the area under the curve (AUC) of the spontaneous contractions of colonic strips (P < 0.05), ii) repeated WAS decreased the endogenous production of H₂S and the expression of H₂S-producing enzymes in the colon devoid of mucosa and submucosa (P < 0.001), iii) cystathionine-γ-lyase (CSE) was strongly expressed in the cytosols of the circular and longitudinal smooth muscle cells and the nucleus of the myenteric plexus neurons, iv) cystathionine-&beta;-synthase (CBS) was primarily localized in the cytosols of myenteric plexus neurons and weakly localized in the epithelial cells and v) inhibitors of H₂S-producing enzymes increased the contractile activity of colonic strips in the SWAS rats (P < 0.001). In conclusion, the results suggest that the colonic hypermotility induced by repeated WAS may be associated with the decreased production of endogenous H2S.
Animals ; Colon ; physiopathology ; Cystathionine beta-Synthase ; metabolism ; Cystathionine gamma-Lyase ; metabolism ; Gastrointestinal Motility ; Hydrogen Sulfide ; metabolism ; Male ; Muscle Contraction ; Myocytes, Smooth Muscle ; metabolism ; Neurons ; metabolism ; Rats ; Rats, Wistar ; Stress, Physiological

OBJECTIVETo investigate plasma hydrogen sulfide (H₂S) levels and cystathionine-gamma- lyase (CSE) and cystathionine-beta-synthase (CBS) mRNA expression in the lung tissues in asthmatic rats and to explore the roles of endogenous H₂S, CSE and CBS system in the pathogenesis of asthma.

METHODSThirty male Sprague-Dawley rats (age 5 to 7 weeks) were randomly divided into three groups: control, asthma and budesonide treatment (n = 10 each). The asthma model was established by ovalbumin (OVA) sensitization and challenge. The budesonide treatment group received inhaled budesonide before challenge. The contents of plasma H₂S were measured by spectrophotometry. The levels of CSE and CBS mRNA in the lung tissues were examined by reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTSThe contents of plasma H₂S in the asthma group (61 ± 16 μmol/L) were significantly lower than those in the control group (84 ± 15 μmol/L) (P<0.01). The contents of plasma H₂S in the budesonide treatment group (71 ± 14 μmol/L) were not statistically different from those in the control and asthma groups. CSE mRNA and CBE mRNA expression in the asthma group were significantly lower than those in the control group (P < 0.01). The budesonide treatment group had a decreased CSE mRNA expression and CBE mRNA expression compared with the control group, but had significantly increased CSE and CBE mRNA expression compared with the asthma group (P < 0.01). There was a significantly negative correlation between H₂S contents in plasma and total inflammatory cells in bronchoalveolar lavage fluid (n = 30, r = -0.549, P < 0.01).

CONCLUSIONSPlasma H₂S levels and CSE and CBS expression in the lung decrease in asthmatic rats, which possibly promotes inflammatory cell aggregation to the airway. Budesonide may alleviate airway inflammation in asthmatic rats possibly through the system of endogenous H₂S, CSE and CBS.

Animals ; Asthma ; drug therapy ; etiology ; metabolism ; Budesonide ; pharmacology ; Cystathionine beta-Synthase ; genetics ; physiology ; Cystathionine gamma-Lyase ; genetics ; physiology ; Hydrogen Sulfide ; metabolism ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley

OBJECTIVEFebrile seizure (FS) is one of the most common seizure types in children. Our previous studies have demonstrated that both gamma-aminobutyric acid B receptor (GABABR) and hydrogen sulfide (H2S) are involved in the pathogenesis of FS. This study was designed to explore the effect of GABABR on H2S/cystathionine-beta-synthase (CBS) system in recurrent FS.

METHODSSixty-four Sprague-Dawley rats aged 21 days were randomly assigned into four groups: Control (37 degrees C water bath exposure), FS, FS+baclofen (GABABR excitomotor), and FS+phaclofen (GABABR inhibitor) groups (n=16 each). FS was induced by warm water bath exposure (45.2 degrees C, once every 2 days, 10 times in total. The plasma level of H2S was detected by the spectrophotometer. The expression of CBS mRNA was examined by in situ hybridization. The expressions of CBS protein was observed by immunohistochemistry.

RESULTSThe plasma level of H2S increased in the FS+baclofen group (427.45 +/- 15.91 micromol/L) but decreased in the FS+phaclofen group (189.72 +/- 21.53 micromol/L) compared with that in the FS group (362.14 +/- 19.71 micromol/L). The expressions of CBS mRNA and protein were up-regulated in the FS+baclofen group but were down-regulated in the FS+phaclofen group compared with those in the FS group.

CONCLUSIONSGABABR modulated the expression of H2S/CBS system in recurrent FS.

Animals ; Baclofen ; pharmacology ; Cystathionine beta-Synthase ; genetics ; physiology ; Hydrogen Sulfide ; blood ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, GABA-B ; physiology ; Recurrence ; Seizures, Febrile ; metabolism

OBJECTIVETo investigate the association of the polymorphisms of methionine metabolism genes and the phenotype of X-linked adrenoleukodystrophy (X-ALD) and clinical severity.

METHODSThe clinical information of 120 X-ALD patients were analyzed and three genetic variants involved in the methionine metabolism, including cystathionine beta-synthase (CBS) c.844_855ins68, 5-methyltetrahydrofolate-homocysteine-S-methyltransferase (MTR) c.2756A to G, and transcobalamin 2 (TC2) c.776 C to G were analyzed by polymerase chain reaction and sequencing. The association between these polymorphisms and phenotype of X-ALD was studied.

RESULTSThe frequency of GG genotype of the TC2 c.776 C/G was higher in patients with central nervous system(CNS) demyelination than in controls (P= 0.012). However, the other two polymorphisms did not show any significant associations with the phenotypes.

CONCLUSIONThe GG genotype of TC2 c.776 C/G may contribute to X-ALD phenotype.

5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase ; genetics ; Adrenoleukodystrophy ; genetics ; Cystathionine beta-Synthase ; genetics ; Gene Frequency ; Genotype ; Humans ; Male ; Methionine ; metabolism ; Phenotype ; Polymorphism, Genetic ; Transcobalamins ; genetics

BACKGROUNDCentral nervous system leukemia (CNSL) is an important relapse in children with acute lymphoblastic leukemia (ALL). We investigated the possible role of endogenous hydrogen sulfide (H(2)S) of cerebrospinal fluid (CSF) in predicting CNSL.

METHODSFrom August 2008 to December 2010, 380 children were enrolled in this study at Shijitan Hospital, China. These children were from 2 to 16 years old, and the median age was 6.5 years. They were divided into a CNSL group (7 cases), a leukemia group (307 cases), a non-leukemia group (26 cases) and a healthy group (40 children). CSF specimens were obtained from conventional lumbar punctured, then centrifuged and supernatants preserved for H(2)S detection. Leukemic cells precipitates from CSF were found in three cases, the hCSE and hCBS mRNA expression was detected by reverse transcription polymerase chain reaction (RT-PCR), and H(2)S levels in serum were also measured. The receiver operating characteristic (ROC) curve and area under curve (AUC) were used to assess the predictive diagnosis role of CSF H(2)S in children with ALL and CNSL.

RESULTSThe serum H(2)S contents of the CNSL and leukemia groups were (96.98 ± 15.77) µmol/L and (93.35 ± 17.16) µmol/L respectively, much higher than those of healthy, (44.29 ± 2.15) µmol/L, and non-leukemia, (46.32 ± 6.54) µmol/L, groups (P < 0.01). Compared with the leukemia group, CSF H(2)S content of the CNSL group was significantly high (P < 0.01). Meanwhile, in contrast to the non-leukemia group, CSF H(2)S contents of the CNSL and leukemia groups were both significantly increased (P < 0.01). In addition, leukemic cells from CSF precipitations could express CBS and CSE mRNA. Furthermore, the ROC analysis showed the UAC was 0.929 (95%CI: 0.857 - 1.000), and the optimum cut-off value of CSF H(2)S was 12.08 µ mol/L, and the sensitivity and specificity were 83.3% and 97.2% respectively.

CONCLUSIONSCSF H(2)S contents were significantly increased in children with CNSL. After treatment, H(2)S contents were decreased subsequently. Therefore, we speculated that H(2)S levels of CSF would predict CNSL in ALL children.

Adolescent ; Central Nervous System Neoplasms ; cerebrospinal fluid ; metabolism ; pathology ; Child ; Child, Preschool ; Cystathionine beta-Synthase ; genetics ; Female ; Humans ; Hydrogen Sulfide ; cerebrospinal fluid ; Leukemia ; cerebrospinal fluid ; Lyases ; genetics ; Male