Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Retinaldehyde”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

Biochemical properties of purified human retinol dehydrogenase 12 (RDH12): catalytic efficiency toward retinoids and C9 aldehydes and effects of cellular retinol-binding protein type I (CRBPI) and cellular retinaldehyde-binding protein (CRALBP) on the oxidation and reduction of retinoids.

Retinol dehydrogenase 12 (RDH12) is a novel member of the short-chain dehydrogenase/reductase superfamily of proteins that was recently linked to Leber's congenital amaurosis 3 (LCA). We report the first biochemical characterization of purified human RDH12 and analysis of its expression in human tissues. RDH12 exhibits approximately 2000-fold lower K(m) values for NADP(+) and NADPH than for NAD(+) and NADH and recognizes both retinoids and lipid peroxidation products (C(9) aldehydes) as substrates. The k(cat) values of RDH12 for retinaldehydes and C(9) aldehydes are similar, but the K(m) values are, in general, lower for retinoids. The enzyme exhibits the highest catalytic efficiency for all-trans-retinal (k(cat)/K(m) approximately 900 min(-)(1) microM(-)(1)), followed by 11-cis-retinal (450 min(-)(1) mM(-)(1)) and 9-cis-retinal (100 min(-)(1) mM(-)(1)). Analysis of RDH12 activity toward retinoids in the presence of cellular retinol-binding protein (CRBP) type I or cellular retinaldehyde-binding protein (CRALBP) suggests that RDH12 utilizes the unbound forms of all-trans- and 11-cis-retinoids. As a result, the widely expressed CRBPI, which binds all-trans-retinol with much higher affinity than all-trans-retinaldehyde, restricts the oxidation of all-trans-retinol by RDH12, but has little effect on the reduction of all-trans-retinaldehyde, and CRALBP inhibits the reduction of 11-cis-retinal stronger than the oxidation of 11-cis-retinol, in accord with its higher affinity for 11-cis-retinal. Together, the tissue distribution of RDH12 and its catalytic properties suggest that, in most tissues, RDH12 primarily contributes to the reduction of all-trans-retinaldehyde; however, at saturating concentrations of peroxidic aldehydes in the cells undergoing oxidative stress, for example, photoreceptors, RDH12 might also play a role in detoxification of lipid peroxidation products.

Alcohol Oxidoreductases↗

Repair of UVA-induced elastic fiber and collagen damage by 0.05% retinaldehyde cream in an ex vivo human skin model.

BACKGROUND: Cellular effects of UV exposure are implicated in cutaneous aging. UV radiations induce structural and cellular changes in all the compartments of skin. AIM: To study the antiaging efficacy of a cream containing 0.05% retinaldehyde with an ex vivo technique using human skin in order to approximate in vivo metabolic conditions. METHODS: Human skin explants were maintained alive in organ culture for 18 days and subjected to UVA exposure, thus simulating skin photoaging. Retinaldehyde cream was then applied to the surface of the epidermis for 2 weeks and the results were compared with those of nontreated skin explants. Dermal repair was analyzed histologically with quantification of collagen and elastic fibers, and biochemically by the measure of newly synthesized collagen as shown by adding tritiated proline to the culture medium. RESULTS: UVA exposure induced significant alterations of collagen and elastic fibers as shown by morphometric analysis. In all UVA-exposed and then retinaldehyde-treated skin specimens, collagen and elastic fibers were restored to the level of nonexposed skin. UVA exposure induced a decrease in collagen synthesis, whereas in retinaldehyde-treated UVA-exposed skin the synthesis was similar to that of unexposed skin. CONCLUSION: It has been shown that retinaldehyde has many of the properties of tretinoin in its biological and beneficial effects on photoaging. We have verified some of these previous observations, especially on dermal connective tissue, by obtaining significant repair of elastic fibers and collagen alteration induced by UVA exposure.

Administration, Topical↗

Retinaldehyde alleviates rosacea.

BACKGROUND: Anecdotal observations suggest that retinoic acid may be effective in mild rosacea. AIM: Our aim was to investigate, by an exploratory clinical and instrumental study, the effects of a topical formulation with the retinoic acid precursor retinaldehyde, in patients with vascular signs of facial rosacea. METHODS: Female patients were treated with a 0.05% retinaldehyde cream that was applied once daily for 6 months. Clinical assessments of persistent erythema and telangiectasia were performed every month, using a 4-point severity score (absent to severe). The clinical response for each parameter was defined as a decrease of at least 1 grade in the severity score. In addition, erythema was further evaluated by measurement of the a* parameter, using a spectrophotometer on lesional and nonlesional areas. RESULTS: A total of 23 women comprised the study population. At baseline, 10 patients had diffuse erythema, 3 patients had isolated telangiectasia and 10 patients had both. During retinaldehyde treatment, a clinical response was revealed in about 75% of the patients with erythema, after 5 months (p < 0.05). Similarly, isolated telangiectasia responded to retinaldehyde, although to a lesser extent and after a longer period of treatment (46% responders after 6 months, nonsignificant). Using the spectrophotometer, the a* parameter diminished in patients with erythema by about 15%, after 2 months of treatment (p = 0.001). CONCLUSION: This study indicates that retinaldehyde has beneficial effects on the vascular component of rosacea.

Administration, Topical↗

Clinical efficacy and safety of a topical combination of retinaldehyde 0.1% with erythromycin 4% in acne vulgaris.

The objective of this randomized, controlled, multicentre study was to assess the efficacy and safety of a topically applied retinaldehyde 0.1% gel in combination with a topical erythromycin 4% lotion for the treatment of acne vulgaris. Treatment consisted of applying either retinaldehyde or its vehicle every morning and erythromycin every evening for 8 weeks. Efficacy parameters were sequential lesion counts for papules and pustules, and a 6-point semiquantitative scale for comedones and microcysts. Safety parameters were local tolerance and adverse events. Of 74 recruited patients, 73 were appraisable for efficacy and safety. In both treatment groups, papules and pustules were reduced significantly at the end of treatment (P < 0.001), and no statistical difference was observed between the groups. Comedones and microcysts were significantly improved with retinaldehyde combined with erythromycin (P = 0.005), but not with erythromycin alone. However, no statistical difference between the groups could be demonstrated (test power, 50%). Local tolerance of the combined treatment group was very satisfactory, as only a few patients experienced local irritation. In conclusion, retinaldehyde combined with erythromycin appears to be a valuable topical therapy in polymorphic acne.

Acne Vulgaris↗

Photoendocrine transduction in cultured chick pineal cells: IV. What do vitamin A depletion and retinaldehyde addition do to the effects of light on the melatonin rhythm?

Light has at least two distinguishable effects on the circadian rhythm of melatonin output displayed by dispersed chick pineal cells in static culture: acute suppression of melatonin output and entrainment (phase shifts) of the underlying pacemaker. Previous results indicated that these two effects of light are mediated by different mechanistic pathways. The pathways for the acute and phase-shifting effects of light either branch from the same, single photopigment or differ from the outset, starting from separate photopigments. If a single rhodopsin-like photopigment mediates both effects of light, then vitamin A depletion and retinoid addition should affect both responses in parallel, although not proportionately. We therefore compared the effects of vitamin A depletion and retinoid addition on the acute and phase-shifting effects of light under several experimental conditions. When chick pineal cells were depleted of vitamin A, acute responses to light were markedly reduced. Addition of 11-cis-retinaldehyde specifically restored (and enhanced) the acute response. When allowed to free run in constant red light, depleted cells displayed a rhythm of melatonin output with the same period as that of control cells. In contrast to the acute effects, phase shifts in response to 2- or 4-h light pulses did not differ between depleted and control cells. Addition of retinaldehyde to depleted cells did not, by itself, reduce melatonin output or induce phase shifts. Retinaldehyde did increase the acute response to 4-h light pulses but not the ensuing phase shifts. Responses increased with duration of the light pulse: Both the acute effect and the phase shifts induced by 4-h light pulses were considerably larger than those induced by 2-h (or 1-h) light pulses. Addition of retinaldehyde to depleted cells increased the acute effect of 2-h (or 1-h) light pulses to at least that seen with 4-h light pulses but did not increase the size of the ensuing phase shifts. These results strongly confirm previous dissociations of the mechanistic pathways mediating the acute and phase-shifting effects of light on chick pineal cells. They also support a role for rhodopsin-like photopigment in the acute, but not phase-shifting, response. They favor, but do not prove, the conclusion that separate photopigments mediate the acute and entraining effects of light.

Activity Cycles↗

Topical retinaldehyde on human skin: biologic effects and tolerance.

The present study was designed to explore if *etinaldehyde, a natural metabolite of vitamin A, has any biologic activity and is tolerated by human skin. Biologic activity was shown by the induction of cellular retinoic acid-binding protein type 2 (CRABP 2) mRNA and protein; the rank order for CRABP-2 increase was retinoic acid > retinaldehyde > 9 cis retinoic acid > retinol > beta carotene. In volunteers treated 1-3 months with 0.5, 0.1, and 0.05% retinaldehyde, there was a dose-dependent and significant increase in epidermal thickness, keratin 14 immunoreactivity, and Ki67-positive cells. The area of distribution of involucrin, transglutaminase, and filaggrin immunoreactivity was also increased in a dose-dependent manner, and keratin 4 immunoreactivity was induced in the upper epidermis. In pilot clinical tolerance studies, 229 patients received topical retinaldehyde at different concentrations; the 1% preparation was tolerated by up to 70% of the treated subjects; tolerance of the 0.5% preparation was slightly better, whereas both 0.1 and 0.05% preparations applied on facial skin were well tolerated and allowed prolonged use (up to 3 years) in patients with inflammatory dermatoses. These findings indicate that topical retinaldehyde has biologic activity and is well tolerated on human skin.

Administration, Topical↗

Clinical use of topical retinaldehyde on photoaged skin.

BACKGROUND: Retinaldehyde, the natural precursor of retinoic acid, should exert similar effects on photoaged skin. OBJECTIVE: To establish the efficacy and safety of topical retinaldehyde on photoaged skin. METHODS: Open and controlled clinical studies using image analysis of silicone skin replicas. RESULTS: Retinaldehyde proved efficient and safe. CONCLUSION: Retinaldehyde is efficient and well tolerated for the improvement of the signs of photoaging.

Administration, Topical↗

Topical retinaldehyde treatment in oral lichen planus and leukoplakia.

The aim of this exploratory study was to assess the efficacy of a natural metabolite of vitamin A, retinaldehyde 0.1%, vehicled in a gel in 17 patients with oral lichen planus and in 13 patients with oral leukoplakia, twice daily for 2 months. Our investigation was clinical, histological, immunohistochemical through the expression of markers of cell terminal differentiation and biochemical by using two-dimensional gel electrophoresis of cytokeratins (CK). In addition, the activity of retinaldehyde was studied ex vivo on surviving buccal mucosa. Retinaldehyde gel 0.1% showed good clinical efficacy, resulting in 6% disappearance and 82% improvement of the lesions in lichen planus and 17% disappearance and 75% improvement in leukoplakia. This was confirmed with immunohistochemistry, which revealed down-regulation of filaggrin and CK-10 as markers of terminal differentiation in both diseases. The effects of retinaldehyde in these two diseases were further demonstrated in the ex vivo surviving mucosal model, resulting in histological disappearance of keratinization in 80% of the lichen planus fragments and 40% of the leukoplakia fragments, associated with down-regulation of filaggrin and CK-10.

Administration, Topical↗

Comparative study of the anti-aging effect of retinaldehyde alone or associated with pretocopheryl in a surviving human skin model submitted to ultraviolet A and B irradiation.

In the past few years, the cellular effects of ultraviolet (UV) irradiation induced on skin have become increasingly recognized. Indeed, it is now well known that UV irradiation induces structural and cellular changes in all the compartments of skin tissue. Our aim was to study the anti-aging efficacy of a cosmetic cream containing 0.05% retinaldehyde associated with an antioxidant such as pretocopheryl in comparison with a cream containing only 0.05% retinaldehyde. For this purpose, an ex vivo technique using human skin was used to approximate in vivo metabolic conditions. In this model, human skin was maintained alive by organ culture for 14 days and skin aging was simulated with UV irradiation. Creams were applied to the surface of the epidermis and were compared with nontreated skin. After 14 days, free radical modulation was analyzed by hydroperoxide dosage. Epidermal (laminin) and dermal changes (elastic fibers and collagen) were studied by a histological method. Moreover, to examine collagen synthesis, tritiated proline was added to the culture medium and its incorporation in the newly synthesized collagen was evaluated by Webster's method. The formula containing 0.05% retinaldehyde and pretocopheryl significantly decreased UV-generated free radicals. Repair of laminin, elastic fiber and collagen network was significant and the results were better than those obtained with retinaldehyde alone. An increase of collagen synthesis was also shown with the two creams.

Adult↗

Enzymatic conversion of retinaldehyde to retinoic acid by cloned murine cytosolic and mitochondrial aldehyde dehydrogenases.

It has previously been reported that retinaldehyde can be converted to retinoic acid by cytosolic aldehyde dehydrogenase (AHD-2) in liver extracts [Biochem. Pharmacol. 42: 1279-1285 (1991)]. To determine which enzyme(s) carried out this reaction in murine embryonic stem cells, two aldehyde dehydrogenases were cloned; the AHD-2 gene was cloned from a liver cDNA library, and a closely related gene, AHD-M1, was cloned from an embryonic F9 cell cDNA library by conserved oligonucleotide sequence screening. AHD-M1 contained an open reading frame of 1554 base pairs, which encoded 517 amino acids. The AHD-M1 gene encoded a protein with a putative amino acid sequence that was 94% and 97% identical to the mitochondrial aldehyde dehydrogenases of human and rat, respectively, and thus we have cloned the murine cDNA for this enzyme for the first time. The AHD-M1 cDNA was only 64% identical to AHD-2. Northern analysis showed that AHD-M1 mRNA was constitutively expressed in F9 and P19 embryonic teratocarcinoma stem cells and in AB1 embryonic stem cells. There was a 3-5-fold retinoic acid-associated increase in the amount of this mRNA during the differentiation of F9 cells into parietal endoderm. In contrast, we could not detect the expression of AHD-2 mRNA in AB1, P19, or F9 cells, even though the F9 cells could convert retinaldehyde to retinoic acid. When the AHD-M1 and AHD-2 cDNAs were inserted into the expression vector pSG5 and transfected into cultured COS cells, 3-5-fold and 100-fold increases, respectively, in the conversion of [3H]retinaldehyde to [3H]retinoic acid could be detected by high performance liquid chromatographic assay. We conclude that both enzymes are capable of converting retinaldehyde to retinoic acid in intact COS cells. AHD-2 is more active than AHD-M1 in this conversion, but AHD-2 is not the enzyme responsible for this conversion in F9 embryonic stem cells.

Aldehyde Dehydrogenase↗

Identification of mouse liver aldehyde dehydrogenases that catalyze the oxidation of retinaldehyde to retinoic acid.

NAD(P)-linked aldehyde dehydrogenases catalyze the oxidation of a wide variety of aldehydes. Thirteen of these enzymes have been identified in mouse tissues; eleven are found in the liver. Some are substrate-nonspecific; others are relatively substrate-specific. The present investigation sought to determine which of these enzymes are operative in catalyzing the oxidation of retinaldehyde to retinoic acid, a metabolite of vitamin A that promotes the differentiation of epithelial and other cells. Spectrophotometric and HPLC assays were used for this purpose. Enzyme-catalyzed oxidation of retinaldehyde (25 microM) was restricted to the cytosol (105,000 g supernatant fraction) and occurred at a rate of 211 nmol/min/g liver; oxidation of acetaldehyde (4 mM) by this fraction proceeds about ten times faster. At least 90% of this activity was NAD dependent. Of the approximately 10% that was apparently NAD independent, two-thirds was inhibited by 1 mM pyridoxal, a known inhibitor of aldehyde oxidase. Of the six cytosolic aldehyde dehydrogenases, only two, viz. AHD-2 and AHD-7, catalyzed the oxidation of retinaldehyde to retinoic acid. An additional NAD-dependent enzyme, viz. xanthine oxidase (dehydrogenase form), also catalyzed the reaction. Catalysis by AHD-2 accounted for more than 90% of the total NAD-dependent activity. Km values were 0.7, 0.6 and 0.9 microM, respectively, for the AHD-2-, AHD-7- and xanthine oxidase (dehydrogenase form)-catalyzed reaction. AHD-4, an aldehyde dehydrogenase found in the cytosol of mouse stomach epithelium and cornea, did not catalyze the reaction.

Aldehyde Dehydrogenase↗

Purification of cellular retinaldehyde-binding protein from bovine retina and retinal pigment epithelium.

Cellular retinaldehyde-binding protein (CRALP) has been purified from extracts of bovine retina or retinal pigment epithelium by a procedure employing an initial, high-capacity anion exchange chromatographic step and anion exchange HPLC for removal of a persistent contaminant. The procedure also yields fractions containing three other retinoid-binding proteins present in retina (cellular retinol-, cellular retinoic acid- and interphotoreceptor retinol-binding proteins; CRBP, CRABP and IRBP, respectively). Procedures are described for labeling CRALBP with 9-cis-retinaldehyde, 11-cis-retinaldehyde, or 11-cis-retinol. There are approx. 3 nmol of CRALBP per adult bovine eye and the binding protein is ca. 0.5% of the soluble protein of a retinal supernatant.

Animals↗

Mutation of the gene encoding cellular retinaldehyde-binding protein in autosomal recessive retinitis pigmentosa.

Inadequate levels of all-trans-retinol in the blood cause retinal dysfunction; hence, genes implicated in retinal vitamin-A metabolism represent candidates for inherited retinal degenerations. In the current study, molecular genetic analysis of a consanguineous pedigree segregating for non-syndromic autosomal recessive retinitis pigmentosa (arRP) indicated that the affected siblings were homozygous by descent for a G4763A nucleotide substitution in RLBP1, the gene encoding cellular retinaldehyde-binding protein (CRALBP). This substitution is predicted to replace an arginine with glutamine at residue 150. CRALBP is not expressed in photoreceptors but is abundant in the retinal pigment epithelium (RPE) and Müller cells of the neuroretina, where it carries 11-cis-retinol and 11-cis-retinaldehyde. When expressed in bacteria, recombinant CRALBP (rCRALBP) containing the R150Q substitution was less soluble than wild-type rCRALBP. Mutant rCRALBP was purified from the soluble cell lysate and the protein structure was verified by mass spectrometry. The mutant protein lacked the ability to bind 11-cis-retinaldehyde. These findings suggest that arRP in the current pedigree results from a lack of functional CRALBP, presumably leading to disruption of retinal vitamin-A metabolism.

Amino Acid Sequence↗

Comedolytic effect of topical retinaldehyde in the rhino mouse model.

BACKGROUND: Retinaldehyde is a key molecule in the metabolism of vitamin A by keratinocytes. In order to evaluate its range of topical activity in acne, its comedolytic effect was compared to that of retinoic acid in the same vehicle, in the rhino mouse model. METHODS: The animals were treated on the back daily for 5 consecutive days per week for 3 weeks. At the end of this period, histological slides were analyzed in order to quantify the features of comedones and epidermal thickness. RESULTS: Topical treatment with a retinaldehyde (0.05% w/w) and a retinoic acid formulation (0. 025% w/w) induced comedolysis and increased the epidermal thickness with the same intensity. CONCLUSION: These data indicate that retinaldehyde exerts a significant comedolytic activity.

Acne Vulgaris↗

Bothnia dystrophy caused by mutations in the cellular retinaldehyde-binding protein gene (RLBP1) on chromosome 15q26.

PURPOSE: To determine the chromosomal location and to identify the gene causing a type of retinitis punctata albescens, called Bothnia dystrophy, found in a restricted geographic area in northern Sweden. METHODS: Twenty patients from seven families originating from a restricted geographic area in northern Sweden were clinically examined. Microsatellite markers were analyzed in all affected and unaffected family members. Direct genomic sequencing of the gene encoding cellular retinaldehyde-binding protein was performed after the linkage analysis had been completed. RESULTS: Affected individuals showed night blindness from early childhood with features consistent with retinitis punctata albescens and macular degeneration. The responsible gene was mapped to 15q26, the same region to which the cellular retinaldehyde-binding protein gene has been assigned. Subsequent analysis showed all affected patients were homozygous for a C to T substitution in exon 7 of the same gene, leading to the missense mutation Arg234Trp. Analysis of marker haplotypes suggested that all cases had a common ancestor who carried the mutation. CONCLUSIONS: A missense mutation in the cellular retinaldehyde-binding protein gene is the cause of Bothnia dystrophy. The disease is a local variant of retinitis punctata albescens that is common in northern Sweden due to a founder mutation.

Adult↗

The complete primary structure of the cellular retinaldehyde-binding protein from bovine retina.

Cellular retinaldehyde-binding protein (CRALBP) carries 11-cis-retinol and 11-cis-retinaldehyde as endogenous ligands and may be a functional component of the visual cycle. The complete amino acid sequence of CRALBP from bovine retina has been determined by direct microanalysis of the protein. Bovine CRALBP contains 316 residues in a single amino-terminal-blocked chain corresponding to a molecular weight of 36,421, inclusive of the blocking group. Overlapping peptides were generated by cleavage of lysyl, arginyl, methionyl, glutamyl, and one tryptophanyl bond and sequenced by gas-phase Edman degradation. Analysis of amino-terminal arginyl and methionyl peptides by fast atom bombardment mass spectrometry identified the N alpha-blocking group as an acetyl moiety, and tandem mass spectrometry provided the sequence of the first 9 residues. Comparison of CRALBP with other known protein sequences reveals no significant structural relatedness. The present results provide a basis for relating CRALBP domains with physiological function and for the future development of a more detailed three-dimensional model of the interaction of 11-cis-retinaldehyde with protein.

Amino Acid Sequence↗

Immunolocalization of cellular retinol-, retinaldehyde- and retinoic acid-binding proteins in rat retina during pre- and postnatal development.

Cellular retinol-, retinaldehyde- and retinoic acid-binding proteins were localized in rat retina during pre- and postnatal development by indirect immunofluorescence. Cryostat tissue sections were prepared daily from embryonic day 11 until the day of birth (E11-22) and from postnatal days 1-32 (P1-32). Cellular retinaldehyde- and retinol-binding proteins were first detected in retinal pigment epithelium on E13 and E18, respectively, and in Müller cells at P1 and P15. Parallel studies showed that in adult retina cellular retinoic acid-binding protein is present in a subpopulation of GABAergic amacrine cells. During retinal differentiation, cellular retinoic acid-binding protein was first detected at E18 in cells sclerad to the developing inner plexiform layer, suggesting that this binding protein is expressed in amacrine cells very early during differentiation. During early ocular morphogenesis, cellular retinoic acid-binding protein was present in mesenchymal cells enveloping the eye (E12-15), in the neuroblastic layer of the retina (E13-15), in the nerve fibre layer (E14-15), and the developing optic nerve (E15). Our results suggest that retinoic acid, the natural ligand of cellular retinoic acid-binding protein, may be involved in neuronal differentiation in the inner retina. The studies further support a role for cellular retinoic acid-binding protein in mediating the effects of retinoic acid on developing neural crest cells and raise new questions about the role of cellular retinaldehyde-binding protein in the visual cycle and during development.

Aging↗

RALDH3, a retinaldehyde dehydrogenase that generates retinoic acid, is expressed in the ventral retina, otic vesicle and olfactory pit during mouse development.

The enzymes that generate retinoic acid during development have been identified as members of the aldehyde dehydrogenase (ALDH) family. The developmental expression patterns of two ALDHs that function as retinaldehyde dehydrogenases, RALDH1 and RALDH2, have been described. Here we report the cloning and expression of a third retinaldehyde dehydrogenase from the mouse called RALDH3 that shares 94% amino acid sequence identity to a human retinaldehyde dehydrogenase previously named ALDH6. In mouse embryos, RALDH3 expression is first noticed in the ventral optic eminence at E8.75, then in the optic vesicle/cup, otic vesicle, and olfactory placode/pit from E9.5 to E11.5. Expression in the developing eye is primarily localized in the ventral retina, thus indicating that RALDH3 represents the V1 dehydrogenase activity described there earlier. From E8.5 to E10.5 RALDH3 expression is distinct from that of RALDH1 or RALDH2, thus indicating a unique role in sensory organ development.

Aldehyde Oxidoreductases↗