Evaluation and treatment of constipation in pregnancy:Examination using the Japanese version of the constipation evaluation scale.

OBJECTIVES: No study has examined the effects of new constipation treatment drugs released in recent years in pregnant women. This prospective cohort study aimed to examine and compare the perinatal prognosis, efficacy rate, and safety of drugs frequently used to treat constipation. METHODS: The study included 211 perinatally managed individuals who answered a self-administered questionnaire during the second trimester and after delivery. The Japanese version of the constipation evaluation scale (Constipation Assessment Scale [CAS] long-term [LT] version) was used for the subjective evaluation of defecation status. RESULTS: Participants aware of constipation had significantly higher CAS scores than those who were unaware. Some participants with a CAS score of 5 points (treatment range) had no subjective symptoms of constipation, whereas some participants with a CAS score of ≤ 5 points were aware of constipation. Regarding the time of onset, 60% of those who had constipation before pregnancy had a high rate of constipation during pregnancy and after delivery. No significant difference was noted in conventional magnesium oxide and polyethylene glycol, a relatively new daily treatment drug, in perinatal prognosis or side effects. CONCLUSIONS: Polyethylene glycol preparations alleviate constipation without inducing diarrhea, making them an appropriate therapeutic option for pregnant women.

Enhancement of Skin Penetration of Hydrophilic and Lipophilic Compounds by pH-sensitive Liposomes.

PURPOSE: Enhance skin penetration of hydrophilic and lipophilic compounds using liposomes that are responsible to the pH of the skin surface. METHODS: pH-sensitive liposomes were prepared by a thin layer and freeze-thaw method with dioleoyl phosphatidyl ethanolamine and cholesteryl hemisuccinate. Liposomal fusion with stratum corneum lipid liposomes was measured using fluorescence resonance energy transfer. Particle diameter and zeta potential of the liposomes after fusion were measured by dynamic light scattering and electrophoresis. RESULTS: Under neutral pH conditions, the diameter of the pH-sensitive liposomes was 130 nm and their zeta potential was -70 mV. In weakly acidic conditions, the diameter was larger than 3,000 nm and the zeta potential was -50 mV. In contrast, the particle diameter and the zeta potential of the non-pH-sensitive liposomes remained constant under various pH conditions. A skin penetration study was performed on hairless mice skin using vertical diffusion cells, showing that the fusion ability of pH-sensitive liposomes was higher than that of non-pH-sensitive liposomes. In the skin penetration study was carried out using hydrophilic (calcein) and lipophilic (N-(7-nitrobenz- 2-oxa-1,3-diazol-4yl)-PE) (NBD-PE) model compounds which were applied to the skin with pH-sensitive liposomes as carrier. The fluorescent compounds contained within the pH-sensitive liposomes permeated the skin more effectively than those within non-pH-sensitive liposomes, and this ability was further enhanced with the lipophilic compound. CONCLUSION: These studies suggest that pH-sensitive liposomes have potential as an important tool for delivery of compounds into the skin.

Esterase Activity and Intracellular Localization in Reconstructed Human Epidermal Cultured Skin Models.

BACKGROUND: Reconstructed human epidermal culture skin models have been developed for cosmetic and pharmaceutical research. OBJECTIVE: This study evaluated the total and carboxyl esterase activities (i.e., Km and Vmax , respectively) and localization in two reconstructed human epidermal culture skin models (LabCyte EPI-MODEL [Japan Tissue Engineering] and EpiDerm [MatTek/Kurabo]). The usefulness of the reconstruction cultured epidermis was also verified by comparison with human and rat epidermis. METHODS: Homogenized epidermal samples were fractioned by centrifugation. p-nitrophenyl acetate and 4-methylumbelliferyl acetate were used as substrates of total esterase and carboxyl esterase, respectively. RESULTS: Total and carboxyl esterase activities were present in the reconstructed human epidermal culture skin models and were localized in the cytosol. Moreover, the activities and localization were the same as those in human and rat epidermis. CONCLUSION: LabCyte EPI-MODEL and EpiDerm are potentially useful for esterase activity prediction in human epidermis.

Effects of low molecular weight soybean peptide on mRNA and protein expression levels of differentiation markers in normal human epidermal keratinocytes.

Low molecular weight soybean peptide (LSP) was applied to normal human epidermal keratinocytes, and the results showed a significant increase in the gene expression levels of involucrin, transglutaminase, and profilaggrin. Filaggrin protein levels were also significantly higher. It is possible that LSP has an epidermal cell differentiation-promoting effect and may be able to regulate metabolism of the epidermis.

Effect of liquid crystals with cyclodextrin on the bioavailability of a poorly water-soluble compound, diosgenin, after its oral administration to rats.

Diosgenin, found in wild yam (Dioscorea villosa), has been shown to ameliorate diabetes and hyperlipidemia, increase cell proliferation in a human 3D skin model, and inhibits melanin production in B16 melanoma cells. It is also an active element in cosmeceutical and dietary supplements. Although the bioavailability of diosgenin is low due to its poor solubility and intestinal permeability, it was subsequently improved using a ß-cyclodextrin (ß-CD) inclusion complex. Recently liquid crystals (LCs) were shown to enhance the bioavailability of poorly water-soluble drugs. The purpose in the present study was to prepare diosgenin LCs and investigate the interaction between LC and ß-CD in order to improve its bioavailability of diosgenin. Crystallinity and particle diameters of LCs in water were determined by small angle X-ray scattering (SAXS) and Zetasizer. Pharmacokinetic parameters were calculated using the plasma content of diosgenin after its oral administration to Wistar rats. Regarding the formation of glyceryl monooleate (GMO) and phytantriol (PHY) LC, SAXS patterns showed the hexagonal and cubic phases, respectively. Bioavailability was significantly enhanced after oral administration of LCs prepared by GMO than after diosgenin alone. The bioavailability was further improved with the combination of LC and ß-CD than LC and water.

Effect of ß-cyclodextrin derivatives on the diosgenin absorption in Caco-2 cell monolayer and rats.

Orally administrated diosgenin, a steroidal saponin found in the roots of Dioscorea villosa, improves reduced skin thickness in ovariectomized mice, and plays an important role in the treatment of hyperlipidemia. Diosgenin has been noticed as an active element in cosmeceutical and dietary supplements. We have already elucidated that the absolute oral bioavailability of diosgenin is very low; however, a high skin distribution of diosgenin was also observed. The aim of the present study was to examine and compare the effects of ß-cyclodextrin (ß-CD) and 3 kinds of its derivatives such as hydroxypropyl ß-CD on the diosgenin permeability using a Caco-2 model and rat jejunal perfusion. These derivatives of ß-CD greatly improved the low solubility of diosgenin. No significant increase was observed in the lactate dehydrogenase leakage from Caco-2 cell, while a slight decrease was found on the transepithelial electrical resistance by diosgenin and ß-CD derivatives. However, ß-CD derivatives, especially hydroxyethyl ß-CD and hydroxypropyl ß-CD, markedly enhanced diosgenin permeability across the Caco-2 monolayer and rat jejunum. The bioavailability of diosgenin in the presence of ß-CD derivatives were about 4 to 11 fold higher than diosgenin suspension. The mechanisms of these enhancement effects may be due to improvements in solubility and tight junction opening.

Enhancement of diosgenin distribution in the skin by cyclodextrin complexation following oral administration.

Orally administrated diosgenin, a steroidal saponin found in several plants including Dioscorea villosa, recovers skin thickness reduced in ovariectomized mice, and plays an important role in the treatment of hyperlipidemia. Thus, diosgenin is an active element of cosmeceutical and dietary supplements. However, we have already elucidated that the skin distribution and absolute oral bioavailability of diosgenin is very low. The aim of this study is to evaluate the efficacy of diosgenin-cyclodextrin (CD) complexes in improving the skin concentration of diosgenin. The formation of the CD complex was indicated by powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and scanning electron microscope (SEM) studies. Oral administration of the diosgenin/ß-CD complex resulted in a significant enhancement in terms of the skin distribution of diosgenin, maximum plasma level (C(max)), area under the plasma concentration-time curve (AUC), and absolute oral bioavailability over those of the drug alone. These results suggest that the inclusion complex of diosgenin/ß-CD can be used to improve low skin content of diosgenin.

Permeation of hyaluronan tetrasaccharides through hairless mouse skin: an in vitro and in vivo study.

Hyaluronan (HA) is a well-known active ingredient for cosmetic and drug applications. However, based on its varying molecular size, HA may have limited skin permeation. Therefore, the aim of the present study was to investigate the in vitro skin permeability of HA tetrasaccharide (HA4). In addition, the effects of HA4 on in vivo skin barrier function were examined. The cumulative amounts of HA4 through stratum corneum (SC)-stripped skin and full-thickness skin after 8 h were 2,109.6 and 0.8 µg/cm(2), respectively. Furthermore, the cumulative amounts of HA4 permeated after 8 h were 784.4 ng/cm(2) for a HA4 solution with a pH 4 and 70.0 ng/cm(2) with a pH 7 on full-thickness skin. Next, the in vivo effects of HA4 on the water content of the SC and transepidermal water loss (TEWL) were investigated. The dorsal skins of hairless mice were irradiated to a UVA dose of 22.3 J/cm(2)/d, 5 times a week. In the control group, the water content of the SC was decreased and TEWL and epidermal thickness were increased with UVA irradiation than the normal group. However, the water content of the SC was increased in the HA4 group than that of the control group in the non-UVA irradiation groups. In addition, the water content of the SC was increased and TEWL and epidermal thickness were decreased in the HA4 group than those of the control and HA groups. These results suggest that treatment with HA4 improved skin functional recovery after UVA irradiation by skin penetration of HA4.

Effects of soybean peptide and collagen peptide on collagen synthesis in normal human dermal fibroblasts.

The collagen present in the dermis of the skin is a fibrous protein that fills the gaps between cells and helps maintain tissue flexibility. Effectively increasing the collagen present in the skin is an important goal for cosmetic research. Recent research has shown that soybean peptide (SP) has anti-fatigue activity, antioxidant activity, and the ability to increase type I collagen, while collagen peptide (CP) has the ability to enhance corneal moisture content and viscoelasticity, as well as to increase levels of hyaluronic acid synthesizing enzymes in human skin. Little documented research, however, has been conducted on collagen formation in relation to these peptides. Therefore, this research applied SP and CP with molecular weights primarily around 500 and preparations containing both SP and CP to normal human dermal fibroblasts together with magnesium ascorbyl phosphate (VC-PMg), and used real-time PCR to determine the gene expression of type I collagen (COL1A1), which contributes to collagen synthesis, and Smad7, which contribute to collagen breakdown. In addition, enzyme linked immuno sorbent assay (ELISA) was used to measure collagen content in the media. COL1A1 gene expression at 24 h after sample addition showed higher tendency in all samples and increased with time at 4, 8 and 24 h after addition. Smad7 gene expression was not substantially different at 4 h after addition. matrix metalloproteinase-1 gene expression was higher following SP addition, but was lower after the addition of CP and SP+CP. Medium collagen content was higher in all samples and increased with time at 8 h after addition. Collagen levels were higher when SP and CP were added together.

Preparation and evaluation of liquid-crystal formulations with skin-permeation-enhancing abilities for entrapped drugs.

The usefulness of liquid crystals (LC) in topical formulations for application to skin was evaluated by measuring the in vitro permeation profile of a model compound, calcein, entrapped in a LC formulation, through excised hairless rat skin and a three-dimensional cultured human-skin model; the viability was determined using the MTT assay. Two physically stable LCs were prepared from a mixture of mono-, di-, and tri-esters 1, and monoesters 2, composed of erythritol and phytanylacetic acid. Cryo-transmission electron microscopy (cryo-TEM), electron diffraction patterns, and small-angle X-ray diffraction (SAXS) observations of the LC nanodispersions showed that the structures of the LCs were reverse hexagonal (LC-A) and cubic (LC-B). The skin-permeation properties of calcein were enhanced by entrapping in the LCs as a result of the increase in calcein partition from the LC dispersion solution into the skin; the properties were analyzed using a skin-permeation-time profile. Drug partitioning could also be modified by the LC structure. No skin damage was caused by the LC formulation in these experiments.The present study suggests that LC dispersions are potential additives in topical drug formulations and cosmetic formulations.

Permeation pathway of macromolecules and nanospheres through skin.

The permeation pathway of macromolecules and nanospheres through skin was evaluated using fluorescent isothiocyanate (FITC)-dextran (average MW, 4 kDa) (FD-4) and nanospheres (500 nm in diameter) in hairless rat abdominal skin and porcine ear skin as well as a three-dimensional cultured human skin model (cultured skin model). A low molecular hydrophilic compound, sodium fluorescein (FL) (MW, 376 Da), was used for comparison. FL penetrated the stratum corneum and permeated the viable epidermis of hairless rat skin, whereas less permeation of FL was observed through the cultured skin model, suggesting that the primary permeation pathway for the hydrophilic material may be skin appendages through the rat skin. A macromolecular compound, FD-4, was distributed through the hair follicles of the rat skin. In addition, nanospheres were detected in the hair follicles of porcine skin, although no skin permeation was detected. These findings suggest that appendage routes such as hair follicles can be a penetration pathway of macromolecules and nanospheres through skin.

Possibility and effectiveness of drug delivery to skin by needle-free injector.

We evaluated a needle-free injector (NFI), which has been studied as an administration device to the subcutaneous tissue, as a device to deliver drugs into skin tissues. ShimaJet used for self-injection of insulin was selected as a spring-powered NFI in this study. Weak (NFI-w) and strong (NFI-s) injectors were evaluated. Rhodamine 6G, as a model compound, was injected onto the skin surface of hairless rats and the skin distribution and amount released from the skin of the compound were followed. A modified nozzle (able to inject at an angle of 45 degrees ) was prepared in addition to the conventional dedicated nozzle. The spring constants, nozzle shapes and penetration enhancer, 1-[2-(decylthio)ethyl] azacyclopentane-2-one (HPE-101), affected not only the skin distribution, but also the release profiles of rhodamine 6G. In addition, the release profiles of rhodamine 6G after injection using NFI-w or NFI-s obeyed diffusion-controlled or membrane-controlled kinetics, respectively. This difference was probably due to the skin site (depth) of rhodamine 6G delivered by the NFI. Furthermore, HPE-101 increased the retention time of rhodamine 6G in the epidermis. The present results suggested that an NFI can be a useful tool for enhanced drug delivery into skin.

Effect of topically applied sphingomyelin-based liposomes on the ceramide level in a three-dimensional cultured human skin model.

Sphingomyelin-based liposomes were prepared and applied to the stratum corneum side or basal layer side of a three-dimensional (3D) cultured human skin model, and the increase in the type II ceramide (ceramide II) content of the cultured skin model was evaluated. The sphingomyelin-based liposomes were prepared by a high-pressure emulsification method, and the obtained liposomes were characterized; the particle diameter and zeta potential of the liposomes were 155.3 nm and -11.4 mV, respectively. Their spherical shape and lamella structure were observed by transmission electron microscopy. The sphingomyelin-based liposomes or saline were applied to the cultured skin model, and ceramide II was extracted from the skin model. The extracted ceramide II was separated by high-performance thin-layer chromatography and quantified by a densitometer. The amount of ceramide II in the cultured skin model was significantly increased by the application of the sphingomyelin-based liposomes, compared with the nonapplication group. Thus, sphingomyelin-based liposomes are useful for enriching the ceramide level in 3D cultured skin models.

Examination of the expression of cyclooxygenase-2 in placenta villi from sufferers of pregnancy induced hypertension.

OBJECTIVES: The purpose of this paper is to elucidate the roles of phospholipase A(2) (PLA(2)), cyclooxygenase-2 (COX-2), and prostaglandin I(2) (PGI(2)) synthase in pregnancy induced hypertension (PIH). METHODS: In placentas from normal pregnant women and pregnant women with severe PIH, the enzyme expression of PLA(2), COX-2, and PGI(2) synthase was measured using real time reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The expression of each enzyme was compared between normal (n=12) and PIH (n=12) groups. The expression levels of COX-2 and PGI(2) synthase during PIH pregnancy were significantly decreased to about 51% and 68%, respectively, of their values in normal pregnancy. However, the expression of PLA(2) was hardly changed by PIH. CONCLUSIONS: The decreases in COX-2 and PGI(2) synthase expression in severe PIH placentas may be causal factors in the disruption of the PGI(2)-thromboxane A(2) (TXA(2)) balance in favor of TXA(2). The decrease in COX-2 was more marked than that of PGI(2) synthase.

[Hormone excretion and peroxisomes of human immortalized extravillous trophoblast cells (TCL-2) derived from first-trimester placenta].

We studied the hormone excretion of human immortalized extravillous trophoblast cells (TCL-2, first-trimester cells) and determined whether peroxisomes are present in TCL-2. The results of TCL-2 were compared with those of TCL-1 (third-trimester cells). Morphologically, TCL-2 cells were fibroblast-like, and the growth rate of TCL-2 was slower than that of TCL-1 during 3 days culture. Progesterone was detected in the medium of TCL-2, and its concentration was approximately one-tenth of that in TCL-1. The activity of the peroxisomal marker enzyme catalase was detected in the TCL-2 homogenate, and it was about one-third the level of that in TCL-1. Fatty acyl-CoA oxidase activity was detected in TCL-2, and it was about one-seventh the level of that in TCL-1. On the other hand, human chorionic gonadotropin (hCG) was detected in the medium of TCL-2, and its concentration after 3 days of culture was about 2-fold that in TCL-1. Using the diaminobenzidine (DAB) method, peroxisomes were found in TCL-2, but only a very small amount of catalase was detected. These results indicate that human immortalized extravillous trophoblast cells (TCL-2) synthesize, secrete hCG and progesterone, and may contain peroxisomes. Because extravillous trophoblast cells are difficult to obtain from the first-trimester placenta, TCL-2 cells are useful for the study of the physiologic functions (including peroxisomal function) of first-trimester cells.

Effects of WY-14643 on peroxisomal enzyme activity and hormone secretion in immortalized human trophoblast cells.

In our previous report, clofibric acid increased both the enzyme activities of peroxisomes (catalase and fatty acyl-CoA oxidase) and the secretion of progesterone in immortalized human extravillous trophoblast cells (TCL-1) (F. Hashimoto et al., Biochem. Pharm., 68, 313 (2004)). WY-14643 is reported to be stronger inducer of peroxisomes in rodents than clofibric acid. Therefore, the effects of WY-14643 on the activities of peroxisomal enzymes and hormone secretion in TCL-1 were studied. After incubation for 3 d with WY-14643, WY-14643 (>/=0.15 mM) suppressed the rate of increase in DNA and protein. The specific activities of catalase were increased by 0.1 mM WY-14643. The specific activities of fatty acyl-CoA oxidase were hardly changed by WY-14643. The concentration of progesterone in the medium was increased by 0.1 mM WY-14643, but human chorionic gonadotropin was decreased by 0.2 mM WY-14643. After a discontinuous Nycodenz-density gradient centrifugation of the light mitochondrial fraction of the cells, catalase activity was distributed in lower density fractions than cytochrome-c oxidase (a mitochondria marker enzyme) activity, but the distribution was not changed by WY-14643. These results suggest that WY-14643 inhibits the proliferation of trophoblast cells. The density of peroxisomes in human trophoblast cells is lower than that of mitochondria, and it is not affected by WY-14643. WY-14643 may increase the progesterone secretion. Effects of WY-14643 on metabolism of human trophoblast cells are different from those of clofibric acid.

Presence and some characteristics of peroxisomes in immortalized human trophoblast cells.

Using morphological and biochemical (Western blot and cell fractionation) methods, we investigated whether peroxisomes are present in human extravillous trophoblast cells. Immortalized extravillous trophoblast cells (TCL-1) were incubated in the presence or absence of 0.5 mM clofibric acid for 3 d. In immunofluorescence staining of trophoblast cells with antibodies anti-catalase and anti-acyl-CoA oxidase (marker enzymes of peroxisomes), electron microscopy and immunoelectron microscopy, peroxisomes were detected in the cells. The size and number of peroxisomes in the trophoblast cells were smaller than those in rat liver. The number of peroxisomes was increased by clofibric acid. In Western blot experiment with antibodies anti-peroxisomal enzymes of beta-oxidation system, densitometric analysis revealed approximately two fold increase in staining by clofibric acid. When we performed cell fractionation experiment using catalase as one of the peroxisomal marker enzymes, the highest activity of catalase was found in the light mitochondrial fraction. Specific activity of catalase in the light mitochondrial fraction was significantly increased to about 1.3 times higher than the control value by clofibric acid treatment. Upon Nycodenz density gradient centrifugation, the catalase activity was concentrated in the density fraction around 1.14-1.15. These findings suggest that microperoxisomes, which have a density smaller than those of rat hepatic peroxisomes, do exist in human extravillous trophoblast cells. It may also be possible to proliferate human peroxisomes in limited quantities using peroxisome proliferator of rodents.

Distribution of dolichol in the serum and relationships between serum dolichol levels and various laboratory test values.

We examined the correlations between serum dolichol levels and laboratory test parameters in patients affected by disease, as well as the distribution of dolichol in sera from patients with hyperbetalipoproteinemia and hyperalphalipoproteinemia. Serum dolichol was evaluated by a reverse-phase HPLC method. After centrifugation, the serum dolichol found in healthy controls was mainly associated with medium-sized particles of the high-density lipoprotein (HDL) fraction. For patients with hyperbetalipoproteinemia, serum dolichol was also associated with the medium HDL fractions. However, for hyperalphalipoproteinemia patients the levels of large HDL and serum dolichol were increased, and serum dolichol was mainly associated with the large HDL fraction. On laboratory tests of components, the dolichol level was not correlated with the values for markers of the liver and biliary system, with the values of renal function markers, with creatine kinase activity, amylase activity or uric acid concentration, but was correlated with total cholesterol, HDL-cholesterol and apoA-I concentrations, and with lactate dehydrogenase (LDH) activity. These results suggest that serum dolichol exclusively localized in HDL, and in subpopulation, that in normocholesterolemia or hyperbeta-cholesterolemia is associated with HDL(3), which is small sized and high density HDL, however, that in hyperalphacholesterolemia is associated with HDL(2), which is large sized and lower density HDL.

PPARalpha agonists clofibrate and gemfibrozil inhibit cell growth, down-regulate hCG and up-regulate progesterone secretions in immortalized human trophoblast cells.

We studied effects of PPARalpha agonists clofibric acid and gemfibrozil on cell growth and functions of immortalized human extravillous trophoblast cells. Levels of DNA and protein gradually increased during incubation for 4 days. Gemfibrozil (>0.25mM) and clofibric acid (2.5mM) suppressed the rate of increase in DNA and protein. Specific activities of fatty acyl-CoA oxidase and catalase were increased to about 1.2-2.0 times the control value by 0.05mM gemfibrozil and 1.0 and 2.5mM clofibric acid after incubation for 3 days. Acid phosphatase activity showed a small increase in response to both agents, but esterase activity changed little. The secretion of progesterone from the cells into the medium was increased by 0.25mM gemfibrozil and 1.0 and 2.5mM clofibric acid after incubation for 3 days, but that of human chorionic gonadotropin (hCG) was decreased by 0.35mM gemfibrozil and 2.5mM clofibric acid. The specific activity of lactate dehydrogenase in the cells was hardly changed at all after incubation for 3 days. These results suggest that gemfibrozil and clofibric acid inhibit the proliferation of trophoblast cells. Cell metabolism is probably affected by both agents. The two agents may down-regulate hCG and up-regulate progesterone secretions.

Effects of peroxisome proliferators gemfibrozil and clofibrate on syntheses of dolichol and cholesterol in rat liver.

The effects of two peroxisome proliferators, gemfibrozil and clofibrate, on syntheses of dolichol and cholesterol in rat liver were investigated. Gemfibrozil did not affect the overall content of dolichyl phosphate, but it changed the chain-length distribution of dolichyl phosphate, increasing the levels of species with shorter isoprene units. Gemfibrozil suppressed synthesis of dolichyl phosphate from [(3)H]mevalonate and [(3)H]farnesyl pyrophosphate in rat liver. In contrast, clofibrate increased the content of dolichol (free and acyl ester forms). It remarkably enhanced dolichol synthesis from mevalonate, but did not affect dolichol synthesis from farnesyl pyrophosphate. Gemfibrozil elevated cholesterol synthesis from [(14)C]acetate, but did not affect the synthesis from mevalonate. Clofibrate suppressed cholesterol synthesis from acetate, but did not affect cholesterol synthesis from mevalonate. These results suggest that gemfibrozil suppresses synthesis of dolichyl phosphate by inhibiting, at the least, the pathway from farnesyl pyrophosphate to dolichyl phosphate. As a result, the chain-length pattern of dolichyl phosphate may show an increase in shorter isoprene units. Clofibrate may increase the content of dolichol by enhancing dolichol synthesis from mevalonate. Gemfibrozil may increase cholesterol synthesis by activating the pathway from acetate to mevalonate. Unlike gemfibrozil, clofibrate may decrease cholesterol synthesis by inhibiting the pathway from acetate to mevalonate.