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RESUMEN Las distonías que responden a levodopa (DRD, siglas en inglés) abarcan un grupo de distonías primarias, causadas por deficiencias enzimáticas en la vía metabólica de las aminas y, por definición, comparten como característica principal su respuesta favorable y sostenida a levodopa. Existen hasta seis genes asociados a DRD, siendo el gen GCH1 el más frecuentemente involucrado. La presentación típica de esta entidad se caracteriza por su aparición en la niñez, distonía de inicio en miembros inferiores con fluctuación diurna, leve parkinsonismo y respuesta clara a dosis bajas de levodopa. Se incluye una búsqueda sistemática de la literatura con casos de DRD publicados en Latinoamérica.
SUMMARY Dopa-responsive dystonia (DRD) encompasses a heterogenous group of primary dystonias, caused by enzymatic deficiencies across the amines pathway and, by definition, show as their main characteristic a favorable and sustained response to levodopa. There are up to 6 genes associated with DRD, including pathogenic variants of the GCH1 gene as the most frequently involved. The typical presentation of DRD is characterized by start in childhood, lower limb-onset dystonia with daytime fluctuation, mild parkinsonism, and a sustained response to low doses of levodopa. A systematic literature search on DRD reported cases in Latin America is presented.
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Objective To investigate the effect of tetrahydrobiopterin (BH4), superoxide dismutase-polyethylene glycol (PEG-SOD) and N(G)-nitro-L-arginine (L-NNA) on impaired endothelial progenitor cell (EPC) functions in DOCA-salt hypertensive mice. Methods DOCA-salt hypertension was created and systolic blood pressure was measured by tail-cuff methods. EPC was isolated from bone marrow of mice and characterized by flow cytometry and fluorescence microscopy. EPC of DOCA-salt mice was incubated with BH4, PEG-SOD, and L-NNA for 24 h, then in vitro EPC function assays were performed. Results Compared with control group, systolic blood pressure was significantly increased in DOCA-salt mice. Both EPC adhesion and angiogenesis functions were impaired in DOCA-salt mice compared to control animals, which were reversed by incubation with BH4, PEG-SOD and L-NNA. Conclusion BH4, PEG-SOD and L-NNA rescued the impairments from EPC functions in DOCA-salt hypertensive mice.
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Most attempts at rational development of new analgesics have failed, in part because chronic pain involves multiple processes that remain poorly understood. To improve translational success, one strategy is to select novel targets for which there is proof of clinical relevance, either genetically through heritable traits, or pharmacologically. Such an approach by definition yields targets with high clinical validity. The biology of these targets can be elucidated in animal models before returning to the patients with a refined therapeutic. For optimal treatment, having biomarkers of drug action available is also a plus. Here we describe a case study in rational drug design: the use of controlled inhibition of peripheral tetrahydrobiopterin (BH4) synthesis to reduce abnormal chronic pain states without altering nociceptive-protective pain. Initially identified in a population of patients with low back pain, the association between BH4 production and chronic pain has been confirmed in more than 12 independent cohorts, through a common haplotype (present in 25% of Caucasians) of the rate-limiting enzyme for BH4 synthesis, GTP cyclohydrolase 1 (GCH1). Genetic tools in mice have demonstrated that both injured sensory neurons and activated macrophages engage increased BH4 synthesis to cause chronic pain. GCH1 is an obligate enzyme for de novo BH4 production. Therefore, inhibiting GCH1 activity eliminates all BH4 production, affecting the synthesis of multiple neurotransmitters and signaling molecules and interfering with physiological function. In contrast, targeting the last enzyme of the BH4 synthesis pathway, sepiapterin reductase (SPR), allows reduction of pathological BH4 production without completely blocking physiological BH4 synthesis. Systemic SPR inhibition in mice has not revealed any safety concerns to date, and available genetic and pharmacologic data suggest similar responses in humans. Finally, because it is present in vivo only when SPR is inhibited, sepiapterin serves as a reliable biomarker of target engagement, allowing potential quantification of drug efficacy. The emerging development of therapeutics that target BH4 synthesis to treat chronic pain illustrates the power of combining human and mouse genetics: human genetic studies for clinical selection of relevant targets, coupled with causality studies in mice, allowing the rational engineering of new analgesics.
Subject(s)
Animals , Humans , Analgesics , Therapeutic Uses , Biopterin , Metabolism , Chronic Pain , Drug Therapy , Genetics , Disease Models, Animal , Drug Discovery , GTP Cyclohydrolase , Genetics , Metabolism , Rodentia , Signal Transduction , GeneticsABSTRACT
The aim of this paper was to study the curative effect of Huotan Jiedu Tongluo (HTJDTL) decoction on a rabbit model with early atherosclerosis (AS),and furtherly to explore whether it could inhibit the BH4/eNOS uncoupling ROS or not. Twenty-four Japanese white rabbits were randomly divided into sham operation group, model group, HTJDTL decoction group and atorvastatin group. Rabbit models with early atherosclerosis were established by high fat diet, nitrogen drying and carotid artery balloon injury. The rabbits were sacrificed at 7th days after balloon injury and several parameters were measured. The pathological morphology of the common carotid artery was observed by HE staining. The blood lipids were detected by peroxidase method. The ratio of vascular eNOS dimer and monomer was measured by Western blot. The ELISA and biochemical technology were respectively used for testing BH4 and ROS levels in serum. The results showed that compared with the sham operation group, the model group had mild stenosis of the common carotid artery lumen, uneven intimal hyperplasia, lipid deposition in the intima and media, and obvious hyperplasia of the adventitia with inflammatory cell infiltration. The HTJDTL decoction could significantly inhibit the intimal hyperplasia compared with the model group, meanwhile, reduce the lipid deposition of the media and the infiltration of the adventitial cells. Compared with the sham operation group, the blood lipids and ROS of the model animals significantly increased, but BH4 and the ratio of eNOS dimer/monomer decreased. Compared with the model group, HTJDTL decoction significantly reduced the TC, ox-LDL and ROS levels, and also up-regulated eNOS dimer/monomer ratio, but it increased BH4 trend without statistical difference. According to the results, it was found that HTJDTL decoction couldsignificantly prevent and improve the vascular remodeling of rabbits model with early atherosclerosis. The mechanism of decoction may largely be related to the inhibition of BH4/eNOS uncoupling and the reduction of oxidative stress.
Subject(s)
Animals , Rabbits , Atherosclerosis , Drug Therapy , Carotid Arteries , Pathology , Drugs, Chinese Herbal , Pharmacology , Nitric Oxide Synthase Type III , Metabolism , Oxidative Stress , Random Allocation , Signal TransductionABSTRACT
Neuropathic pain is one of the most common chronic pain in clinic, and its treatment has always been a global difficulty, mainly because its pathogenesis is unknown. GTP cyclohydrolase 1 (GCH1) mediated neuropathic pain by regulating inflammatory cytokines. Besides, GCH1 is also the main speed limit in the process of tetrahydrobiopterin (BH4) enzyme synthesis. BH4 is a necessary cofactor for the synthesis of various inflammatory factors and neurotransmitters. In the study of its relationship with pain, it was found that when the GCH1 gene was silent, the pain was relieved and the expression of BH4 decreased. The results suggest that GCH1 and BH4 have a certain relationship with neuropathic pain.
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Objective To study the characteristics of hyperphenylalaninemia (HPA) and the differences in blood and urine metabolic index and their correlation.Methods A total of 137 patients with HPA diagnosed by the Pediatric Inherit Metabolism and Endocrine Department,Guangdong Women and Children's Hospital,Guangzhou Medical University from January 2014 to June 2017,were enrolled.Tandem mass spectrometry (MS/MS),gas chromatography/ mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC) were used to analyze the concentration of blood and urine metabolites in children,and the patients were divided into different groups according to the drug load test of tetrahydrobiopterin (BH4) and dihydrobiopterindine reductase (DHPR) deficiency.The HPA metabolite analysis of horizontal concentration by statistical differences and correlation analysis were performed.Results Among the 137 cases of HPA,there were 101 cases (73.7％) of phenylalanine hydroxylase deficiency (PAH),and among them 21 cases (15.3％) were classic phenylketonuria (PKU),37 cases were mild PKU (27.0％),43 cases (31.4％) wcrc mild HPA.Thcrc were 22 cases (16.1％) with BH4 reaction,and 79 cases (57.7％) of non-reactive type.Besides,there were 36 cases (26.3％) of tetrahydrobiopterin deficiency (BH4 D),of which 6-pyruvoyl tetrahydropterin synthase deficiency (PTPS) in 34 cases (24.8％) and dihydrobiopterindine reductase deficiency (DHPR) in 2 cases (1.5％).Urinary phenylacetic acid (r =0.673,P ＜ 0.01),phenyllactic acid (r =0.736,P ＜ 0.01),phenylpyruvic acid (r =0.642,P ＜ 0.01) were significantly correlated with blood phenylalanine (Phe) concentration,and the neopterin (N) (r =0.442,P ＜ 0.01) and biopterin (B) (r =0.398,P ＜ 0.01) had low correlation.Urinary phenylacetic acid,phenyllactic acid and phenylpyruvic acid had no correlation with urinary pterin.There were significant differences among PTPS deficiency group,BH4 response type,and non-reactive type(all P ＜ 0.05),but no significant difference between the BH4 reaction type and the non-reactive group (P ＞ 0.05).Conclusions Through the analysis of the different types of HPA metabolic profiles,it can help to master the incidence and characteristics in the region,within a certain concentration range of blood Phe,the phenylacetic acid,phenyllactic acid,phenylpyruvic acid should not be tested by GC-MS alone.Uterine erythropoietin analysis of BH4D classification and identification of BH4 reaction,non-reactive PKU have a supporting role,so master the metabolic index of various types of concentration and relevance of HPA,it can provide basis for early diagnosis,accurate treatment and follow-up.
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Since 1981,neonatal screening of hyperphenylalaninemia(HPA) has been carrying on in China.The newborns with phenylketonuria(PKU) have been good growthing and developing.Some of them already take part in the marriage period.The fetal brain developmental disorders and various teratogenesis could be leaded if the pregnant women with PKU have high blood concentration of phenylalaninine,namely,maternal PKU syndrome would happen.Now,the international latest progress,including mechanism,prevention,tetrahydrobiopterin support treatment of maternal PKU and the comprehensive management for adult female patients with PKU were summarized,and would like to provide some references for preventing the occurrence of maternal PKU syndrome.
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Aim To observe the effects of tetrahydro-biopterin ( BH4 ) on nitric oxide ( NO ) production in the kidney of type 2 diabetic nephropathy ( DN) mice, and to find a new target for the treatment of type 2 DN. Methods The 12 week-old db/db mice developed in-to DN phase were divided into 2 groups:DAHP group, subjected to intraperitoneal injection of 150 mg·kg-1 DAHP (n=8);DN group, subjected to intraperitone-al injection of same dose of normal saline containing 5% DMSO ( n = 6 ) . The age-matched db/m mice ( NS group) were subjected to intraperitoneal injection of same dose of normal saline containing 5% DMSO ( n =6 ) . Three groups of mice were treated for 7 days. Then the fasting blood-glucose, serum creatinine, u-rine protein and activity of iNOS were determined by chemical colorimetry. And the iNOS protein in renal cortex was determined by immunohistochemisty and western blot, respectively. BH4 was measured by HPLC method. NO level was determined by Griess method. Results The levels of fasting blood-glucose, serum creatinine, 24h urine volume, 24h urine pro-tein, BH4 , iNOS and NO in DN group were signifi-cantly higher than those in NS group;The levels of ser-um creatinine, urine volume, urine protein, BH4 , iN-OS and NO in DAHP group were significantly lower than those in DN group. Conclusion In the kidney of type 2 DN mice, the increased BH4 contributes to over-production of NO by the increased iNOS expression, and resultes in the increase of urine volume and urine protein.
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It has been suggested that transition metal ions such as iron can produce an oxidative injuries to nigrostriatal dopaminergic neurons, like Parkinson's disease (PD) and subsequent compensative increase of tetrahydrobiopterin (BH4) during the disease progression induces the aggravation of dopaminergic neurodegeneration in striatum. It had been established that the direct administration of BH4 into neuron would induce the neuronal toxicity in vitro. To elucidate a role of BH4 in pathogenesis in the PD in vivo, we assessed the changes of dopamine (DA) and BH4 at striatum in unilateral intranigral iron infused PD rat model. The ipsistriatal DA and BH4 levels were significantly increased at 0.5 to 1 d and were continually depleting during 2 to 7 d after intranigral iron infusion. The turnover rate of BH4 was higher than that of DA in early phase. However, the expression level of GTP-cyclohydrolase I mRNA in striatum was steadily increased after iron administration. These results suggest that the accumulation of intranigral iron leads to generation of oxidative stress which damage to dopaminergic neurons and causes increased release of BH4 in the dopaminergic neuron. The degenerating dopaminergic neurons decrease the synthesis and release of both BH4 and DA in vivo that are relevance to the progression of PD. Based on these data, we propose that the increase of BH4 can deteriorate the disease progression in early phase of PD, and the inhibition of BH4 increase could be a strategy for PD treatment.
Subject(s)
Disease Progression , Dopamine , Dopaminergic Neurons , Ions , Iron , Models, Animal , Neurons , Oxidative Stress , Parkinson Disease , RNA, MessengerABSTRACT
BACKGROUND: Defects either in phenylalanine hydroxylase (PheOH) or in the production and recycling of its cofactor (tetrahydrobiopterin [BH4]) are the causes of primary hyperphenylalaninemia (HPA). The aim of our study was to investigate the current status of different variants of HPA Kurdish patients in Kermanshah province, Iran. MATERIALS AND METHODS: From 33 cases enrolled in our study, 32 were identified as HPA patients. Reassessing of pre‑treatment phenylalanine concentrations and the analysis of urinary pterins was done by high‑performance liquid chromatography method. RESULTS: A total of 30 patients showed PAH deficiency and two patients were diagnosed with BH4 deficiency (BH4/ HPA ratio = 6.25%). Both of these two BH4‑deficient patients were assigned to severe variant of dihydropteridine reductase (DHPR) deficiency. More than 75% of patients with PAH deficiency classified as classic phenylketonuria (PKU) according their levels of pre‑treatment phenylalanine concentrations. CONCLUSION: Based on the performed study, we think that the frequency of milder forms of PKU is higher than those was estimated before and/or our findings here. Furthermore, the frequency of DHPR deficiency seems to be relatively high in our province. Since the clinical symptoms of DHPR deficiency are confusingly similar to that of classic PKU and its prognosis are much worse than classical PKU and cannot be solely treated with the PKU regime, our pilot study support that it is crucial to set up screening for BH4 deficiency, along with PAH deficiency, among all HPA patients diagnosed with HPA.
Subject(s)
Adolescent , Child , Child, Preschool , Consanguinity , Female , Humans , Iran , Male , Phenylketonurias/diagnosis , Phenylketonurias/epidemiology , Phenylketonurias/genetics , Phenylalanine Hydroxylase/deficiency , Phenylalanine Hydroxylase/etiology , Phenylalanine Hydroxylase/genetics , Young AdultABSTRACT
Until recently,the common treatment for phenylketonuria (PKU) was a phenylalanine (Phe)-restricted diet.Increasing evidence of suboptimal outcomes was observed in diet-treated individuals.The observation of clinically significant reductions in blood Phe levels in a subset of patients with PKU following oral administration of tetrahydrobiopterin(BH4),a cofactor of phenylalanine hydroxylase.Clinical studies suggest that treatment with BH4 provides better Phe control and increases dietary Phe tolerance,allowing significant relaxation or even discontinuation of dietary Phe restriction.The current knowledge on this novel pharmacologic approach to the treatment of PKU will be discussed.
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Tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide synthase (NOS) activity, is known to play important roles in modulating both NO and superoxide production during vascular diseases such as atherosclerosis. However, the role of BH4 in functions of vascular smooth muscle cells is not fully known. In this study, we tested the effects of BH4 and dihydrobiopterin (BH2), a BH4 precursor, on migration and proliferation in response to platelet-derived growth factor-BB (PDGF-BB) in rat aortic smooth muscle cells (RASMCs). Cell migration and proliferation were measured using a Boyden chamber and a 5-bromo-2'-deoxyuridine incorporation assay, respectively, and these results were confirmed with an ex vivo aortic sprout assay. Cell viability was examined by 2,3-bis [2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide assays. BH4 and BH2 decreased PDGF-BB-induced cell migration and proliferation in a dose-dependent manner. The inhibition of cell migration and proliferation by BH4 and BH2 was not affected by pretreatment with N G-nitro-L-arginine methyl ester, a NOS inhibitor. Moreover, the sprout outgrowth formation of aortic rings induced by PDGF-BB was inhibited by BH4 and BH2. Cell viability was not inhibited by BH4 and BH2 treatment. The present results suggest that BH4 and BH2 may inhibit PDGF-stimulated RASMC migration and proliferation via the NOS-independent pathway. Therefore, BH4 and its derivative could be useful for the development of a candidate molecule with an NO-independent anti-atherosclerotic function.
Subject(s)
Animals , Rats , Atherosclerosis , Biopterin , Bromodeoxyuridine , Cell Movement , Cell Survival , Muscle, Smooth , Muscle, Smooth, Vascular , Myocytes, Smooth Muscle , Nitric Oxide , Nitric Oxide Synthase , Proto-Oncogene Proteins c-sis , Superoxides , Vascular DiseasesABSTRACT
Oxidative damage is thought to be a major cause of the progression of dopamine (DA)rgic neurodegeneration as in Parkinson's disease. We have previously reported that tetrahydrobiopterin (BH4), an endogenous molecule required for DA synthesis, exerts oxidative stress to DA-producing cells and facilitates the production of DA quinone. It is known that aconitase, present in both mitochondrial and cytosolic forms, act as an reactive oxygen species (ROS) sensor, and that their inactivation leads to further generation of ROS. In the present study we investigated whether the BH4-associated vulnerability of DA cells might involve aconitase. In DArgic cell line CATH.a, BH4 treatment caused reduction of activity of both mitochondrial and cytosolic aconitases, and this appeared to be due to direct inactivation of the pre-existing enzyme molecules. Although most of the activity reduced by BH4 was increased upon reactivation reaction under a reducing condition, the restoration was not complete, suggesting that irreversible and covalent modification has occurred. The aconitase inactivation was exacerbated in the presence of DA and attenuated in the presence of tyrosine hydroxylase inhibitor a-methyl-p-tyrosine, suggesting the involvement of DA. The degree of inactivation increased when the cells were treated with the quinone reductase inhibitor dicoumarol and decreased in the presence of quinone reductase inducer sulforaphane. Taken together, BH4 appeared to lead to both reversible and irreversible inactivation of aconitase and that this is facilitated by the presence of DA and accumulation of DA quinone.
Subject(s)
Aconitate Hydratase , Benzoquinones , Biopterin , Cell Line , Cytosol , Dicumarol , Dopamine , NAD(P)H Dehydrogenase (Quinone) , Oxidative Stress , Parkinson Disease , Reactive Oxygen Species , Thiocyanates , Tyrosine 3-MonooxygenaseABSTRACT
PURPOSE: To investigate the effects of dexamethasone (DEX) on the production of nitric oxide (NO) and its enzymatic synthetic pathway in cultured human trabecular meshwork (HTM) cells. METHODS: Primarily cultured HTM cells were exposed to 0, 10, 100, 1000 nM of DEX for 3 days. In addition, 100 micrometer sepiapterin, 100 micrometer ascorbic acid, and 10 micrometer methotrexate were co-exposed to DEX. The cellular survival and nitrite production rates were assessed by MTT assay and Griess assay, respectively. RESULTS: DEX did not significantly affect the survival of cultured HTM cells. DEX decreased the NO production in a dose-dependent manner. With co-exposure of DEX, ascorbic acid nullified the DEX-induced decrease of NO production. Sepiapterin and methotrexate did not affect DEX-induced decrease of NO production. CONCLUSIONS: DEX decreased NO production in HTM cells and the de novo pathway of tetrahydrobiopterin may be involved. This decrease may raise intraocular pressure by decreasing trabecular outflow.
Subject(s)
Humans , Ascorbic Acid , Biopterin , Dexamethasone , Intraocular Pressure , Methotrexate , Nitric Oxide , Pterins , Trabecular MeshworkABSTRACT
PURPOSE: To investigate the effects of dexamethasone (DEX) on the production of nitric oxide (NO) and its enzymatic synthetic pathway in cultured human trabecular meshwork (HTM) cells. METHODS: Primarily cultured HTM cells were exposed to 0, 10, 100, 1000 nM of DEX for 3 days. In addition, 100 micrometer sepiapterin, 100 micrometer ascorbic acid, and 10 micrometer methotrexate were co-exposed to DEX. The cellular survival and nitrite production rates were assessed by MTT assay and Griess assay, respectively. RESULTS: DEX did not significantly affect the survival of cultured HTM cells. DEX decreased the NO production in a dose-dependent manner. With co-exposure of DEX, ascorbic acid nullified the DEX-induced decrease of NO production. Sepiapterin and methotrexate did not affect DEX-induced decrease of NO production. CONCLUSIONS: DEX decreased NO production in HTM cells and the de novo pathway of tetrahydrobiopterin may be involved. This decrease may raise intraocular pressure by decreasing trabecular outflow.
Subject(s)
Humans , Ascorbic Acid , Biopterin , Dexamethasone , Intraocular Pressure , Methotrexate , Nitric Oxide , Pterins , Trabecular MeshworkABSTRACT
Tetrahydrobiopterin (BH4) deficiency is caused by mutations in genes encoding enzymes involved in the synthesis and regeneration of BH4. The condition is usually accompanied by hyperphenylalaninemia (HPA) and deficiency of neurotransmitter precursors L-dopa and 5-hydroxytryptophan. BH4 deficiency is much rarer than classical phenylketonuria. Dihydropteridine reductase (DHPR) deficiency, an autosomal recessive genetic disorder, is a cause of malignant hyperphenylalaninemia due to BH4 deficiency. When left untreated, DHPR deficiency leads to neurologic deterioration at the age of 4 or 5 months, including psychomotor retardation, tonicity disorders, drowsiness, irritability, abnormal movements, hyperthermia, hypersalivation, and difficulty swallowing. Treatment of DHPR deficiency should be initiated as early as possible with BH4 supplementation and replacement of the neurotransmitter precursors L-dopa and 5-hydroxytryptophan. We report the first case of DHPR deficiency in Korea, a child diagnosed at 9 years of age by genetic testing.
Subject(s)
Child , Humans , 5-Hydroxytryptophan , Biopterin , Deglutition , Dihydropteridine Reductase , Dyskinesias , Fever , Genetic Testing , Korea , Levodopa , Neurotransmitter Agents , Phenylketonurias , Regeneration , Sialorrhea , Sleep StagesABSTRACT
PURPOSE: Phenylketonuria(PKU) is an inborn error of metabolism and a genetic disorder resulting from a deficiency of phenylalanine hydroxylase(PAH) and decreased activity of tetrahydrobiopterin(BH4).In this study the correlation between the DNA mutation and clinical manifestations was investigated and PAH DNA mutations were compared bewteen Asian and Caucasian populations. METHODS: DNA was isolated from peripheral leukocytes. The PAH gene was amplified by Polymerase Chain Reaction(PCR) and the sequence was analyzed with Multiplex Ligation-dependent Probe Amplification(MLPA). RESULTS: We characterized the PAH gene of 102 independent Korean patients with PKU. PAH nucleotide sequence analysis revealed 44 different mutations, including 10 novel mutations comprising 9 missense mutations(N207D, K95del, A447P, G344D, P69S, S391I, A202T, G103S, and I306L) and 1 novel splice-site variant mutation(IVS10-3C>G). R243Q was the most prevalent mutation in this study. A259T has not previously been reported in Asian populations, but we found that this mutation had a frequency of 10.1% in our study. Furthermore, the genotypes of BH4 responsive patients were analyzed and were divided into two groups: BH4 medication-only group and BH4 medication with diet therapy group. In the BH4 medication-only group and BH4 medication with diet therapy group, R241C was the most common mutation. CONCLUSION: Novel mutations in the PAH gene of PKU patients are still being discovered. Additional information as to the frequency of mutations in the tetrahydrobiopterine responsive gene is also accumulating. We anticipate that knowledge of these PKU gene mutations will assist the diagnosis, genetic counseling, and therapeutic treatment of PKU patients in future.
Subject(s)
Humans , Asian People , Base Sequence , DNA , Genetic Counseling , Genotype , Leukocytes , Phenylalanine , Phenylalanine Hydroxylase , PhenylketonuriasABSTRACT
PURPOSE: To investigate the effect of insulin on the production of nitric oxide (NO) in the trabecular meshwork (TM) cells and the enzymatic synthetic pathway of tetrahydrobiopterin (BH4) synthesis. METHODS: Primarily cultured human TM cells were exposed to 1, 10, and 100 microgram/ml of insulin and 0, 1, 10, 100 and 1000 nM dexamethasone for 3 days. To evaluate the enzymatic pathway of BH4 synthesis, 10 micrometer dexamethasone, 5 mM diaminopyrimidinone, 100 micrometer ascorbic acid, 100 micrometer sepiapterin, or 10 micrometer methotrexate were also co-administered respectively. Cellular survival and NO production were measured with MTT and Griess assay. RESULTS: Insulin enhanced NO production in a dose-dependent manner significantly (p<0.05) without affecting cell viability, whereas dexamethasone inhibited NO production. With co-exposure of insulin, diaminopyrimidinone and sepiapterin inhibited insulin-induced NO production. Ascorbic acid increased NO production independent of insulin and methotrexate did not affect to the action of insulin in NO production. CONCLUSIONS: Insulin increases NO production in TM cells via de novo synthetic pathway for BH4 synthesis. Insulin could be involved in the regulation of trabecular outflow by enhancing NO production in TM cells.
Subject(s)
Humans , Trabecular Meshwork/cytology , Nitric Oxide/biosynthesis , Insulin/administration & dosage , Dose-Response Relationship, Drug , Cells, Cultured , Cell Survival/drug effects , Biopterin/analogs & derivativesABSTRACT
Objective To explore clinical characteristics of phenylalanine hydroxylase(PAH) deficiency in differential diagnosis among hyperphenylalaninemia(HPA) patients and compare the responses to diet treatment in HPA patients.Methods Tetrahydrobiopterin(BH4,20 mg/kg) loading test or combined phenylalanine(Phe,100 mg/kg) and BH4 loading test was carried out among 44 HPA patients.The urine pterine profile analysis and dihydropteridine reductase(DHPR) activity in dry blood filter spot were analyzed simultaneously.Electroencephalogram(EEG) and average full scale development quotient(DQ) were performed in all patients.PAH deficiency patients were given low Phe diet treatment to decrease Phe level for 120-360 ?mol/L and followed up their Phe tolerance.Results Twelve BH4 responsive PAH deficiency patients were diagnosed who were 7 males and 5 females,mean age was 7.8 months.Their metabolic phenotype was moderate or mild HPA.Diet control could decrease Phe level among BH4 deficiency patients but not prevent their neural damage and their EEG abnormal rate was higher.BH4 responsive patients had higher DQ than others and their Phe tolerance increased during diet treatment.Conclusions BH4 responsive PAH deficiency patients can obtain better purpose with diet recipe.The differential diagnosis for BH4 deficiency shall be carried out in all patients with HPA as soon as possible.
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Objective To evaluate the influence of tetrahydrobiopterin on NO and MDA concentration and SOD activity as well as the myocardial infarction area. Methods Twenty-four rabbits were divided into three groups randomly: control group,MI/R group and BH 4 group. After occlusion of the left anterior descending coronary artery of a rabbit for 60 minutes followed by 90 minutes of reperfusion (ischemia/reperfusion),NO and MDA and SOD concentrations were measured and the myocardial infarction area was caculated. Results Compared with control group,the NO concentration in MI/R group was markedly decreased [(28?10) ?mol/L vs (116?17) ?mol/L,P 0.05];There was significant difference between MI/R and BH 4 groups in infarction area,too. [(18?4)% vs (16?4)%,P