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1.
Zhonghua Fu Chan Ke Za Zhi ; 58(4): 270-276, 2023 Apr 25.
Artigo em Chinês | MEDLINE | ID: mdl-37072295

RESUMO

Objective: To explore the effects of pregnancy complicated with moyamoya disease on maternal and fetal outcomes. Methods: The general clinical data and maternal and fetal outcomes of 20 pregnancies of 15 patients with moyamoya disease admitted to the First Affiliated Hospital of Zhengzhou University from January 2012 to October 2022 were retrospectively analyzed. Results: (1) General information: among the 20 pregnancies of 15 clearly diagnosed pregnant women complicated with moyamoya disease, 12 were diagnosed before pregnancy (60%, 12/20), 3 were diagnosed during pregnancy (15%, 3/20), and 5 were diagnosed during puerperal period (25%, 5/20). There were 7 cases of primipara (35%, 7/20) and 13 cases of multipara (65%, 13/20). (2) Pregnancy complications and maternal and infant outcomes: among the 20 pregnancies of 15 pregnant women with moyamoya disease, there were 9 pregnancy complications (45%, 9/20), including 5 gestational hypertension (25%, 5/20), 2 severe pre-eclampsia (10%, 2/20), 1 hyperlipidemia and 1 gestational diabetes mellitus (5%, 1/20). There were 2 case of drug abortion in the first trimester, 3 cases of labor induction in the second trimester, and 15 cases of delivery during the third trimester. All the 15 deliveries were cesarean section, of which 11 (11/15) were cesarean sections with medical indications, and 4 (4/15) were cesarean sections caused by personal factors. General anesthesia was used in 5 cases (5/15), epidural block anesthesia in 7 cases (7/15), and combined spinal and epidural anesthesia in 3 cases (3/15). The median gestational age of 15 neonates was 37.2 weeks (34.0 to 40.8 weeks), with 10 cases (10/15) were full-term infants, and 5 (5/15) were preterm infants (3 of which were associated with hypertensive disorder complicating pregnancy). The birth weight of 15 neonates was (2 853±454) g. Four neonates were admitted to neonatal intensive care unit (NICU), of which 3 cases were admitted to NICU due to premature delivery and 1 case was admitted to NICU due to neonatal jaundice. There was no neonatal asphyxia or death. All neonates were followed up from 4 months to 6 years after birth, and all grew well. (3) Neurological symptoms during pregnancy: 8 cases (40%, 8/20) had neurological symptoms during pregnancy, and 6 cases (30%, 6/20) had hemorrhagic symptoms, of which 3 cases occurred during the puerperal period (3/6). There were 2 cases of ischemic symptoms (10%, 2/20), all of which occurred during the puerperal period (2/2). (4) Analysis of factors related to the occurrence of cerebral hemorrhage: the incidence of cerebral hemorrhage in patients with moyamoya disease diagnosed before pregnancy was significantly lower than that in those without a clear diagnosis, and the incidence of cerebral hemorrhage in women with moyamoya disease was lower than that in primipara (all P<0.01). The incidence of cerebral hemorrhage in moyamoya patients without hypertensive disorder complicating pregrancy was lower than that in patients with hypertensive disorder complicating pregrancy, but the difference was not statistically significant (P>0.05). Conclusions: Pregnancy combined with moyamoya disease has adverse effects on maternal and infant outcomes, and the incidence of pregnancy complications increases. Cerebral hemorrhage occurres in prenatal and puperium, while cerebral ischemia occurres mainly in puperium.


Assuntos
Doença de Moyamoya , Complicações na Gravidez , Lactente , Gravidez , Recém-Nascido , Feminino , Humanos , Resultado da Gravidez , Cesárea , Gestantes , Recém-Nascido Prematuro , Doença de Moyamoya/complicações , Estudos Retrospectivos , Complicações na Gravidez/epidemiologia , Hemorragia Cerebral
2.
Zhonghua Fu Chan Ke Za Zhi ; 57(2): 91-100, 2022 Feb 25.
Artigo em Chinês | MEDLINE | ID: mdl-35184469

RESUMO

Objective: To explore the effects of pregnancy complicated with Takayasu arteritis (TA) on maternal and fetal outcomes. Methods: The clinical data of 17 TA patients with pregnancy and finally terminated admitted to the First Affiliated Hospital of Zhengzhou University from January 2012 to December 2020 were collected and the maternal and infant outcomes were retrospectively analyzed. Results: Among the 24 pregnancies in 17 TA patients in our hispital, 11 patients in our hospital were primiparous (46%, 11/24) and 13 patients were multiparous (54%, 13/24); 4 cases of chronic hypertension before pregnancy (17%, 4/24), and 20 cases of non-hypertension (83%, 20/24) were abserved. Apart from the thoracoabdominal artery type, 15 cases (63%, 15/24) of brachiocephalic type, 8 cases (33%, 8/24) of extensive type, and 1 case of pulmonary artery type (4%, 1/24) were included in TA classification; the renal artery was damaged in 7 cases (7/8) of the extensive type. Among the 24 pregnancies of 17 TA patients, 8 cases of pregnancy complications occurred, including 4 cases (17%, 4/24) of preeclampsia, one case of (4%, 1/24) new-onset hypertension during pregnancy, exacerbation of existing hypertension, thrombocytopenia and ischemic stroke respectively; 3 cases of induced abortion, 1 case of induced labor, and 20 cases of final delivery were found. Of the 20 final deliveries, 3 cases (15%, 3/20) were delivered through the vagina; 17 cases (85%, 17/20) were delivered by cesarean section; 3 cases (15%, 3/20) of fetal growth restriction and 6 cases of oligohydramnios (30%, 6/20) were occurred. The median gestational age of pregnancy termination of 17 full-term neonates (85%, 17/20) and 3 premature neonates (15%, 3/20) was 38.4 weeks (range:29.6-40.9 weeks). All premature women were complicated with pre-eclampsia or severe pre-eclampsia, which lead to premature birth; the birth weight of the neonates was (2 791±783) g. Neonatal asphyxia occurred in 3 cases (15%, 3/20), and 6 cases (30%, 6/20) were admitted to the neonatal intensive care unit. None of the newborns died. The patients were followed up for 3 months to 7 years. Except for one case who underwent surgical treatment 3 years after delivery and died of intraoperative hemorrhage, the other 16 patients were in stable condition; all the newborns grew and developed well. The incidences of maternal and infant adverse events were higher in those with chronic hypertension, renal artery involvement, and no use of hormones and aspirin during pregnancy, but the differences were not statistically significant (all P>0.05). Conclusions: Pregnancy with TA has adverse effects on maternal and infant outcomes. To reduce the occurrence of maternal and child adverse events, the condition of TA patients should be fully assessed before pregnancy, multidisciplinary cooperation, regular treatment, strengthened monitoring of the condition, timely treatment of complications, selection of appropriate delivery methods after pregnancy, and vigilance of postpartum complications should be properly carried out.


Assuntos
Pré-Eclâmpsia , Arterite de Takayasu , Cesárea , Criança , Feminino , Retardo do Crescimento Fetal/epidemiologia , Humanos , Lactente , Recém-Nascido , Pré-Eclâmpsia/epidemiologia , Gravidez , Resultado da Gravidez , Estudos Retrospectivos , Arterite de Takayasu/complicações , Arterite de Takayasu/tratamento farmacológico , Arterite de Takayasu/epidemiologia
3.
Vet J ; 232: 1-5, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29428082

RESUMO

Cluster differentiation antigen 14 (CD14) is an important pattern recognition receptor protein in innate immunity. The aim of this study was to identify and assess the association of single-nucleotide polymorphisms (SNPs) in the CD14 gene with susceptibility to bovine tuberculosis (BTB) in Chinese Holstein cows. DNA samples from 517 Chinese Holstein cows (257 tuberculosis positive cases and 259 healthy controls) were collected from dairy farms in China. SNPs in the entire CD14 gene, including exonic regions, intronic regions and close to the 5'- and 3'-terminal untranslated regions, were detected by PCR, followed by direct sequencing. Five SNPs (-5C/T, 613G/A, 1023G/A, 1306G/A and 1326G/T) were found in the CD14 gene region. Significantly increased BTB susceptibility was evident in T allele carriers of -5C/T (P<0.001; odds ratio, OR 2.02; 95% confidence interval, CI 1.57-2.77), G allele carriers of 613G/A (P<0.001; OR 2.17, 95% CI 1.50-3.08) and TG haplotype carriers of both SNPs (P<0.001; OR 3.14, 95% CI 1.24-4.50). These results suggest that -5C/T and 613G/A are risk factors for BTB in Chinese Holstein cattle and might be used as candidate genetic markers in breeding cows with natural resistance to BTB.


Assuntos
Bovinos/genética , Predisposição Genética para Doença/genética , Receptores de Lipopolissacarídeos/genética , Polimorfismo de Nucleotídeo Único/genética , Tuberculose Bovina/genética , Animais , China , DNA , Feminino , Técnicas de Genotipagem/veterinária , Haplótipos
4.
Physiol Res ; 63(3): 341-50, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24564599

RESUMO

This study investigated the effects of riboflavin on energy metabolism in hypoxic mice. Kunming mice were fed diets containing riboflavin at doses of 6, 12, 24 and 48 mg/kg, respectively for 2 weeks before exposure to a simulated altitude of 6000 m for 8 h. Changes of riboflavin status and energy metabolism were assessed biochemically. Simultaneously, a (1)H nuclear magnetic resonance (NMR) based metabolomic technique was used to track the changes of plasma metabolic profiling. It was found that the content of hepatic riboflavin was decreased and erythrocyte glutathione activation coefficient was elevated significantly under hypoxic condition. Meanwhile, increased plasma pyruvate, lactate, beta-hydroxybutyrate and urea, as well as decreased plasma carnitine were observed. Riboflavin supplementation improved riboflavin status remarkably in hypoxic mice and decreased plasma levels of pyruvate, free fatty acids and beta-hydroxybutyrate significantly. Plasma carnitine was increased in response to riboflavin supplementation. Results obtained from (1)H NMR analysis were basically in line with the data from biochemical assays and remarkable changes in plasma taurine, choline and some other metabolites were also indicated. It was concluded that riboflavin requirement was increased under acute hypoxic condition and riboflavin supplementation was effective in improving energy metabolism in hypoxic mice.


Assuntos
Metabolismo Energético/efeitos dos fármacos , Hipóxia/sangue , Riboflavina/uso terapêutico , Complexo Vitamínico B/uso terapêutico , Ácido 3-Hidroxibutírico/sangue , Animais , Glicemia/efeitos dos fármacos , Carnitina/sangue , Suplementos Nutricionais , Avaliação Pré-Clínica de Medicamentos , Ácidos Graxos não Esterificados/sangue , Hipóxia/tratamento farmacológico , Ácido Láctico/sangue , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Ácido Pirúvico/sangue , Distribuição Aleatória , Riboflavina/farmacologia , Ureia/sangue , Complexo Vitamínico B/farmacologia
5.
Amino Acids ; 31(1): 73-80, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16715412

RESUMO

Starting from a collection of 1386 druggable compounds obtained from the 3D pharmacophore search, we performed a similarity search to narrow down the scope of docking studies. The template molecule is KZ7088 (Chou et al., 2003, Biochem Biophys Res Commun 308: 148-151). The MDL MACCS keys were used to fingerprint the molecules. The Tanimoto coefficient is taken as the metric to compare fingerprints. If the similarity threshold was 0.8, a set of 50 unique hits and 103 conformers were retrieved as a result of similarity search. The AutoDock 3.011 was used to carry out molecular docking of 50 ligands to their macromolecular protein receptors. Three compounds, i.e., C(28)H(34)O(4)N(7)Cl, C(21)H(36)O(5)N(6), and C(21)H(36)O(5)N(6), were found that may be promising candidates for further investigation. The main feature shared by these three potential inhibitors as well as the information of the involved side chains of SARS Cov Mpro may provide useful insights for the development of potent inhibitors against SARS enzyme.


Assuntos
Antivirais/farmacologia , Desenho de Fármacos , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/efeitos dos fármacos , Antivirais/química , Sítios de Ligação , Ligação de Hidrogênio , Ligantes , Testes de Sensibilidade Microbiana , Modelos Moleculares , Conformação Proteica , Relação Estrutura-Atividade
6.
Arch Dermatol Res ; 290(4): 215-22, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9617442

RESUMO

Epidermal permeability barrier homeostasis requires the postsecretory processing of polar lipid precursors into nonpolar lipid products within the stratum corneum (SC) interstices by a family of lipid hydrolases. A specific requirement for beta-glucocerebrosidase (beta-GlcCer'ase), which exhibits a distinct acidic pH optimum, is particularly well documented. Therefore, we sought to determine whether the recovery of the barrier after acute insults requires acidification of the SC. We examined permeability barrier recovery by assessing changes in transepidermal water loss (TEWL), SC membrane ultrastructure utilizing ruthenium tetroxide (RuO4) postfixation, and beta-GlcCer'ase activity by in situ zymography at an acidic vs neutral pH. Barrier recovery proceeded normally when acetone-treated skin was exposed to solutions buffered to an acidic pH. In contrast, the initiation of barrier recovery was slowed when treated skin was exposed to neutral or alkaline pH, regardless of buffer composition. In addition, enhancement of the alkaline buffer-induced delay in barrier recovery occurred with Ca2+ and K+ inclusion in the buffer. Moreover, the pH-dependent alteration in barrier recovery appeared to occur through a mechanism that was independent of Ca(2+)- or K(+)-controlled lamellar body secretion, since both the formation and secretion of lamellar bodies proceeded comparably at pH 5.5 and pH 7.4. In contrast, exposure to pH 7.4 (but not pH 5.5) resulted in both the persistence of immature, extracellular lamellar membrane structures, and a marked decrease in the in situ activity of beta-GlcCer'ase. These results suggest first that an acidic extracellular pH is necessary for the initiation of barrier recovery, and second that the delay in barrier recovery is a consequence of inhibition of postsecretory lipid processing.


Assuntos
Permeabilidade da Membrana Celular/fisiologia , Fenômenos Fisiológicos da Pele , Animais , Soluções Tampão , Cátions/metabolismo , Espaço Extracelular/química , Espaço Extracelular/metabolismo , Concentração de Íons de Hidrogênio , Masculino , Lipídeos de Membrana/metabolismo , Camundongos , Camundongos Pelados , Concentração Osmolar , Pele/citologia , Pele/ultraestrutura
7.
Arch Dermatol Res ; 289(3): 138-44, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9128761

RESUMO

Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteases which play key roles in extracellular matrix remodeling, connective tissue damage, inflammation and cell proliferation in a variety of tissues. Since MMP inhibitors have been recently shown to decrease proliferation of vascular smooth-muscle cells, and to prevent neutrophil infiltration in response to alkali burns, we sought to determine whether MMPs play a role in the pathogenesis of inflammatory or hyperproliferative skin disorders. The effects of a specific MMP inhibitor and its analogues on phorbol dibutyrate (PdiBu)-induced inflammation and epidermal hyperplasia in murine skin were assessed. Topical GM 6001, a hydroxamic acid analog with potent inhibitory activity against several MMPs, markedly inhibited PdiBu-induced increases in both ear thickness and ear punch-biopsy weight in a dose-dependent manner 30 h after topical application of PdiBu. Maximal inhibition (75%) was obtained at a dose of 100 micrograms/cm2 (P < 0.01). Moreover, histologic analysis revealed that GM 6001 decreased both the inflammatory cellular infiltrates and epidermal hyperplasia induced by PdiBu. Whereas similar results were found for GM 1489, an analog of GM 6001, acetohydroxamic acid, containing the critical metal ligand group but without the amino acid side chains necessary for binding to the MMPs, did not alter the response to PdiBu inflammation/hyperplasia. These results show that the MMP inhibitors, GM 6001 and GM 1489, are effective in reducing both the inflammatory and hyperproliferative responses that occur following topical phorbol ester application, suggesting a potential role for MMPs in cutaneous inflammatory dermatoses. Moreover, the delivery of this class of inhibitors across intact stratum corneum implies that MMP inhibition could provide an approach to the topical treatment of inflammatory dermatoses.


Assuntos
Dermatite de Contato/patologia , Matriz Extracelular/enzimologia , Metaloendopeptidases/antagonistas & inibidores , Inibidores de Proteases/farmacologia , Pele/efeitos dos fármacos , Pele/patologia , Animais , Dermatite de Contato/etiologia , Dipeptídeos/farmacologia , Hiperplasia , Camundongos , Camundongos Pelados , Dibutirato de 12,13-Forbol/farmacologia , Triptofano/análogos & derivados , Triptofano/farmacologia
8.
J Pharm Sci ; 85(6): 643-8, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8773963

RESUMO

The intercellular domains of the stratum corneum, which contain a mixture of cholesterol, free fatty acids, and ceramides, mediate both the epidermal permeability barrier and the transdermal delivery of both lipophilic and hydrophilic molecules. Prior studies have shown that each of the three key lipid classes is required for normal barrier function. For example, selective inhibition of either cholesterol, fatty acid, or ceramide synthesis in the epidermis delays barrier recovery rates after barrier perturbation of hairless mouse skin in vivo. In this study, we investigated the potential of certain inhibitors of lipid synthesis to enhance the transdermal delivery of lidocaine or caffeine as a result of their capacity to perturb barrier homeostasis. After acetone disruption of the barrier, the extent of lidocaine delivery and the degree of altered barrier function paralleled each other. Moreover, the further alteration in barrier function produced by either the fatty acid synthesis inhibitor 5-(tetradecyloxy)-2-furancarboxylic acid (TOFA), the cholesterol synthesis inhibitor fluvastatin (FLU), or cholesterol sulfate (CS) resulted in a further increase in lidocaine absorption. Furthermore, coapplications of TOFA and CS together caused an additive increase in lidocaine uptake. Finally, a comparable increase in drug delivery occurred when the barrier was disrupted initially with DMSO instead of acetone; coapplications of TOFA and FLU together again delayed barrier recovery and increased drug delivery by about 8-fold vs delivery from a standard enhancing vehicle. Whereas these metabolic inhibitors also variably increased the octanol/water partitioning of the drugs studied (perhaps via complexion or pH alterations), physicochemical effects of the inhibitors alone did not alter drug uptake in intact skin; i.e., passive mechanisms alone cannot account for the net increase in drug delivery. Our results show that modulations of epidermal lipid biosynthesis, following application of conventional, chemical penetration enhancers, cause a further boost in drug delivery, attributable to the ability of these agents to alter both permeability barrier homeostasis and thermodynamics. This biochemical/metabolic approach provides a novel means to enhance transdermal drug delivery in conjunction with the concurrent or prior use of chemical enhancers.


Assuntos
Anticolesterolemiantes/farmacologia , Colesterol/biossíntese , Ácidos Graxos/biossíntese , Hipolipemiantes/farmacologia , Absorção Cutânea/efeitos dos fármacos , Pele/efeitos dos fármacos , Pele/metabolismo , Acetona/farmacologia , Administração Cutânea , Animais , Fenômenos Químicos , Físico-Química , Ésteres do Colesterol/farmacologia , Ácidos Graxos Monoinsaturados/farmacologia , Fluvastatina , Furanos/farmacologia , Indóis/farmacologia , Lidocaína/farmacocinética , Masculino , Camundongos , Camundongos Pelados , Permeabilidade
9.
Arch Dermatol Res ; 287(3-4): 254-8, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7598529

RESUMO

Sphingolipids, the predominant lipid species in mammalian stratum corneum play, a central role in permeability barrier homeostatis. Prior studies have shown that the epidermis synthesizes abundant sphingolipids, a process regulated by barrier requirements, and that inhibition of sphingolipid synthesis interferes with barrier homeostasis. To investigate further the relationship between epidermal sphingolipid metabolism and barrier function, we localized sphingolipid synthetic activity in murine epidermis under basal conditions, and following acute (acetone treatment) or chronic (essential fatty acid deficiency, EFAD) barrier perturbation, using dithiothreitol and/or the staphylococcal epidermolytic toxin to isolate the lower from the outer epidermis. Under basal conditions, both the activity of serine palmitoyl transferase (SPT), the rate-limiting enzyme of sphingolipid synthesis, and the rates of 3H-H2O incorporation into sphingolipids were nearly equivalent in the lower and the outer epidermis. Following acute barrier perturbation, SPT activity increased significantly in both the lower (35%; P < 0.05) and the outer epidermal layers (60%; P < 0.01). The rates of 3H-H2O incorporation into each major sphingolipid family, including ceramides, glucosylceramides and sphingomyelin, increased significantly in both the lower and the outer epidermis of treated flanks after acute barrier disruption. Finally, SPT activity was modestly elevated (20%; P < 0.01) in the lower but not in the outer epidermis of EFAD animals. These studies demonstrate the ability of both lower and outer epidermal cells to generate sphingolipids, and that permeability barrier homeostatic mechanisms appear to differentially regulate SPT activity and sphingolipid synthesis in the lower and the outer epidermis in response to acute and chronic barrier perturbation.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Aciltransferases/metabolismo , Epiderme/metabolismo , Esfingolipídeos/biossíntese , Acetona/toxicidade , Animais , Colesterol/biossíntese , Epiderme/efeitos dos fármacos , Ácidos Graxos Essenciais/deficiência , Homeostase , Masculino , Camundongos , Camundongos Pelados , Permeabilidade/efeitos dos fármacos , Serina C-Palmitoiltransferase
10.
J Clin Invest ; 88(4): 1338-45, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1918384

RESUMO

Stratum corneum lipids comprise an approximately equimolar mixture of sphingolipids, cholesterol, and free fatty acids, arranged as intercellular membrane bilayers that are presumed to mediate the epidermal permeability barrier. Prior studies have shown that alterations in epidermal barrier function lead to a rapid increase in cholesterol and fatty acid synthesis which parallels the early stages of the repair process. Despite an abundance of indirect evidence for their role in the barrier, the importance of sphingolipids has yet to be demonstrated directly. Whereas sphingolipid synthesis also increases during barrier repair, this response is delayed in comparison to cholesterol and fatty acid synthesis (Holleran, W.M., et al. 1991. J. Lipid Res. 32:1151-1158). To further delineate the role of sphingolipids in barrier homeostasis, we assessed the impact of inhibition of sphingolipid synthesis on epidermal barrier recovery. A single topical application of beta-chloro-L-alanine (beta-CA), an irreversible inhibitor of serine-palmitoyl transferase (SPT), applied to acetone-treated skin of hairless mice resulted in: (a) greater than 75% inhibition of SPT activity at 30 min (P less than 0.001); (b) a global decrease in sphingolipid synthesis between 1 and 3 h (P less than 0.02); (c) reduction of epidermal sphingolipid content at 18 h (P less than 0.01); (d) delayed reaccumulation of histochemical staining for sphingolipids in the stratum corneum; and (e) reduced numbers and contents of lamellar bodies in the stratum granulosum. Finally, despite its immediate, marked diminution of sphingolipid synthesis, beta-CA slowed barrier recovery only at late time points (greater than 6 h) after acetone treatment. This inhibition was overridden by coapplications of ceramides (the distal SPT product), indicating that the delay in repair was not due to non-specific toxicity. These studies demonstrate a distinctive role for epidermal sphingolipids in permeability barrier homeostasis.


Assuntos
Epiderme/metabolismo , Esfingolipídeos/fisiologia , Aciltransferases/análise , Animais , Colesterol/metabolismo , Epiderme/efeitos dos fármacos , Epiderme/ultraestrutura , Masculino , Camundongos , Camundongos Pelados , Permeabilidade , Serina C-Palmitoiltransferase , Esfingolipídeos/biossíntese , beta-Alanina/análogos & derivados , beta-Alanina/farmacologia
11.
J Lipid Res ; 32(7): 1151-8, 1991 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1940639

RESUMO

A mixture of sphingolipids, cholesterol, and free fatty acids forms the intercellular membrane bilayers of the stratum corneum which are presumed to regulate epidermal barrier function. Prior studies have shown that both cholesterol and fatty acid synthesis are rapidly regulated by epidermal barrier requirements. In contrast, the importance of sphingolipids in barrier function has not been directly demonstrated. Here, we have assessed both sphingolipid synthesis by [3H]H2O incorporation and serine palmitoyl transferase (SPT) activity in relation to modulations in barrier function. Incorporation of [3H]H2O into sphingolipids increased after barrier disruption with acetone, with maximal increase (170%) occurring 5-7 h after treatment (P less than 0.005). As barrier function returned to normal over 24 h, incorporation of tritium into sphingolipids normalized. SPT activity also increased after barrier disruption, peaking at 6 h (150%) (P less than 0.05), and returning towards normal by 24 h. Artificial restoration of the barrier with a water vapor-impermeable membrane prevented the increases in both [3H]H2O incorporation into sphingolipids and enzyme activity. Finally, SPT activity was increased in two other models of barrier dysfunction, cellophane tape-stripping and essential fatty acid deficiency. Occlusion normalized SPT activity in both of these models as well. These studies: a) demonstrate a distinctive, delayed increase in epidermal sphingolipid synthesis in response to barrier requirements that contrasts with the immediate responses of cholesterol and fatty acid synthesis; and b) suggest that sphingolipids are important for the maintenance of the epidermal permeability barrier.


Assuntos
Permeabilidade da Membrana Celular , Epiderme/metabolismo , Esfingolipídeos/biossíntese , Acetona/farmacologia , Aciltransferases/metabolismo , Animais , Permeabilidade da Membrana Celular/efeitos dos fármacos , Epiderme/enzimologia , Masculino , Camundongos , Camundongos Pelados , Microssomos/enzimologia , Modelos Biológicos , Serina C-Palmitoiltransferase
12.
J Lipid Res ; 31(9): 1655-61, 1990 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2246616

RESUMO

Sphingolipids comprise approximately 25% of the stratum corneum lipids and are considered critical constituents of the epidermal permeability barrier. Whether sphingoid base structures are synthesized in the epidermis or whether they are derived from circulating or dermal sources is not known. We report here the initial characterization of serine-palmitoyl transferase (EC 2.3.1.50; SPT), the rate-limiting enzyme in the synthesis of sphingolipids, from cultured human neonatal keratinocytes. Subcellular fractionation studies demonstrated that 79% of the total cellular SPT activity was associated with the microsomes. The specific activity of keratinocyte SPT was 270 +/- 20 pmol/min per mg of microsomal protein, a level significantly higher than activities reported in other tissues. Keratinocyte SPT showed an apparent Km for L-serine of 0.40 (+/- 0.04 mM, with an alkaline pH optimum (8.2 +/- 0.4). Keratinocyte SPT utilizes palmitoyl-CoA preferentially over other saturated or unsaturated acyl-CoA substrates; increasing acyl-CoA chain lengths above C16 by one or two carbons was less detrimental to activity than similar decrements in chain length. Finally, the mechanism-based inhibitors L-cycloserine and beta-chloro-L-alanine, demonstrated potent inhibition of keratinocyte SPT activity, with 50% inhibitory concentrations of approximately 3.0 and 25 microM, respectively. In summary, we have found that cultured human neonatal keratinocytes contain unusually high levels of serine-palmitoyl transferase activity, and that the substrate specificity of keratinocyte SPT may determine the base composition of epidermal sphingolipids.


Assuntos
Aciltransferases/metabolismo , Queratinócitos/enzimologia , Aciltransferases/antagonistas & inibidores , Aciltransferases/química , Células Cultivadas , Humanos , Cinética , Microssomos/enzimologia , Serina C-Palmitoiltransferase , Frações Subcelulares/enzimologia , Especificidade por Substrato/fisiologia
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