Identification of Drugs that Regulate Dermal Stem Cells and Enhance Skin Repair.

Here, we asked whether we could identify pharmacological agents that enhance endogenous stem cell function to promote skin repair, focusing on skin-derived precursors (SKPs), a dermal precursor cell population. Libraries of compounds already used in humans were screened for their ability to enhance the self-renewal of human and rodent SKPs. We identified and validated five such compounds, and showed that two of them, alprostadil and trimebutine maleate, enhanced the repair of full thickness skin wounds in middle-aged mice. Moreover, SKPs isolated from drug-treated skin displayed long-term increases in self-renewal when cultured in basal growth medium without drugs. Both alprostadil and trimebutine maleate likely mediated increases in SKP self-renewal by moderate hyperactivation of the MEK-ERK pathway. These findings identify candidates for potential clinical use in human skin repair, and provide support for the idea that pharmacological activation of endogenous tissue precursors represents a viable therapeutic strategy.

Pharmacokinetic study of trimebutine maleate in rabbit blood using in vivo microdialysis coupled to capillary electrophoresis.

In vivo microdialysis was used together with capillary electrophoresis (CE) to monitor the concentration of trimebutine maleate (TM) in rabbit blood. Dialysis probe was perfused at 3 microl/min resulting in relative recovery of 26.6+/-3.1% (n=3). After a one step sample preparation the samples were injected directly into the capillary. TM was detected on-column using UV detector at 214 nm. Separation of TM from other components in the dialysate was achieved within 15 min. Evaluation was based on the relative collected peak height (TM/IS). The response for TM in the blood dialysate was linear over the range of 0.5-100 microg/ml. The detection limit of TM in the blood dialysate was 0.1 microg/ml (S/N=3). This method has been successfully applied to the pharmacokinetic study of trimebutine maleate in rabbit blood following oral administration of 200 mg/kg. It provides a fast and simple technique for the pharmacokinetic study of TM in vivo.

Effects of trimebutine on sphincter of Oddi motility in patients with post-cholecystectomy pain.

BACKGROUND: Trimebutine is an opiate modulator of the gastrointestinal motility that interacts with enkephalinergic receptors. AIM: To evaluate the effects of trimebutine (50 mg intravenous injection) on the motility of the sphincter of Oddi (SO) as assessed by endoscopic manometry. METHODS: Endoscopic manometry was performed on 15 cholecystectomized patients who presented with symptoms suggestive of SO dysfunction. Prior to the endoscopic manometry, endoscopic ultrasonography was performed in order to rule out the possible presence of a bile duct stone. RESULTS: Injecting trimebutine resulted in a significant increase in the SO antegrade phasic contraction rate (P = 0.02). Trimebutine decreased the basal pressure of the SO (32.5 vs. 27.5 mmHg), but the difference is not statistically significant (P = 0.11). The effects of trimebutine differed depending on the basal SO motility anomalies involved, but the period of latency was similar (mean 89 s: range 30-240 s). The basal anomalies were an increased basal SO pressure of > 40 mmHg in three patients, a tachyoddia (frequency of phasic contractions (PC) > 10/min) in six patients, prolonged PC (> 10 s) in two patients and an absence of phasic contraction in one patient. The basal pressure of the SO decreased in the three patients presenting with SO hyperpressure, but returned to a normal value in one case. The frequency of the PC decreased to normal in three out of the six patients with tachyoddia. The duration of the PC returned to normal in the two patients with prolonged PC whereas their frequencies increased. Prolonged PC developed in the patient without any detectable phasic contraction. CONCLUSIONS: Trimebutine modulates SO motility in various ways depending on the basal SO motility anomaly observed after cholecystectomy. This regulatory effect suggests the existence of encephalinergic control of SO motility.

The role of remote gut inflammation in duodenojejunal dysmotility.

The aim of this prospective study was to determine the role of remote inflammation of the gut on duodenojejunal motor status by comparing patients with acute cholecystitis (AC) to those with biliary colic (BC). Thirty-six gallstone patients (11 AC and 25 BC) were explored. Manometric recordings were performed during fasting and after a 750-kcal meal and ended by an intravenous injection of 100 mg trimebutine. Patient data were compared to those of 20 healthy controls. Phases III were more frequently absent in AC patients than in BC patients (P < 0.01) and controls (P < 0.05). When phase III characteristics were similar between the AC and BC group, the phase III amplitude was lower in both groups than in controls (P < 0.0001). After the meal, the mean motor index in the jejunum expressed by the area under the curve (AUC) per 30-min period was higher in the AC group than in BC group and controls (P < 0.05). Specific motor phenomena were observed after the meal. In particular, propagating clusters of contractions (PCCs) were more frequent in AC patients than in BC (P < 0.05) and controls (P < 0.01). A lack of the expected decrease in the AUC during recording occurred with the same frequency in the AC and BC groups but was more frequent in patients than in controls (P < 0.05). In 8/11 patients in the AC group with duodenojejunal tracings before and 3 months after surgery, preoperative motor disturbances disappeared in 5/8 patients and improved in 3/8 patients. The higher frequency of duodenojejunal motor disturbances especially after a meal in patients with AC and their disappearance in most of the patients after removal of the infected gallbladder suggest that remote inflammation of the gut affects duodenojejunal motility.

Peripheral antagonistic action of trimebutine and kappa opioid substances on acoustic stress-induced gastric motor inhibition in dogs.

The effects of intracerebroventricular (i.c.v.), intravenous (i.v.) and oral (p.o.) administration of trimebutine on the gastric motor inhibition induced by acoustic stress were investigated in fasted dogs fitted with strain-gauge transducers on the antrum and proximal jejunum. Started 40-50 min after the last migrating motor complex, a 1 h acoustic stress delayed by 111% the occurrence of the next gastric migrating motor complex without affecting the jejunal motor pattern. This inhibition of gastric migrating motor complex induced by acoustic stress was abolished by previous p.o. administration of trimebutine (1 mg/kg) but not by its i.v. (0.1 mg/kg) or i.c.v. (0.01 mg/kg) injection. The trimebutine blockade of gastric motor alterations induced by acoustic stress was suppressed after previous i.v. treatment with MR 2266 (0.3 mg/kg) but was unaffected by naloxone (0.3 mg/kg). Furthermore oral administration of U-50488H (10 micrograms/kg) and ethylketocyclazocine (10 micrograms/kg) respectively abolished and reduced the acoustic stress-induced delay of the occurrence of the gastric migrating motor complex. We concluded that trimebutine is able to antagonize the gastric motor disturbances induced in dogs by acoustic stress, probably by acting selectively on peripheral kappa receptors located in the wall of the proximal gut and directly stimulated from a mucosal site.

Effects of trimebutine maleate on gastric motility in patients with gastric ulcer.

The effects of trimebutine maleate (TM), a prokinetic drug, on gastrointestinal motility in patients with gastric ulcer were investigated. Twenty patients with active gastric ulcers were allocated to two groups; 10 patients received a proton pump inhibitor alone (PPI group), given orally, and 10 patients received oral TM in combination with a PPI (PPI + TM group), each for a period of 8 weeks. Electrogastrography (EGG) and gastric emptying were measured before and after the treatment period. During the active ulcer stage, tachygastria (more than 0.06 Hz) or bradygastria (less than 0.04 Hz) in the EGG frequency were observed in 9 patients either before or after meals. During the healed ulcer stage, tachygastria or bradygastria was observed in 4 of 10 patients in the PPI group, while in the PPI + TM group, 1 patient had tachygastria and none had bradygastria. Postprandial dip (PD) was observed in 3 of the 20 patients during the active stage, while after treatment, PD was observed in 3 patients in the PPI group and in 6 patients in the PPI + TM group, respectively. Gastric emptying in the PPI group did not show any change between before and after treatment, while that in the PPI + TM group improved significantly after treatment. These results suggest that TM may have an ameliorative effect on abnormal gastric motility in patients with gastric ulcer.

Beneficial effect of trimebutine and N-monodesmethyl trimebutine on trinitrobenzene sulfonic acid-induced colitis in rats.

The use of local anesthetics, such as lidocaine, has been proposed in the treatment of distal ulcerative colitis. Trimebutine maleate (TMB) displays a local anesthetic activity higher than that of lidocaine in rabbit corneal reflex. TMB and nor-TMB its main metabolite in human show similar affinity to that of bupivacaine toward sodium channel labeled by [3H]batrachotoxin and block sodium currents in sensory neurons from rat dorsal root ganglia. The aim of this study was to evaluate the effects of TMB and nor-TMB in comparison to lidocaine and bupivacaine in a rat model of acute colonic inflammation induced by trinitrobenzene sulfonic acid (TNBS). A single intracolonic instillation of TNBS (50 mg/kg dissolved in ethanol 30%) led to early plasma extravasation then macroscopic damage (hyperemia and necrosis), increased colonic weight and tissular MPO, a marker of neutrophilic infiltration. Local administration of TMB at dose of 3 to 60 mg/kg, 30 min before, 24 and 48 h after colitis induction, significantly reduced the severity of colitis. Nor-TMB (1, 3, 10, 30 mg/kg) as well as lidocaine (1, 3, 10 mg/kg) dose-dependently reduced colitis while bupivacaine at 10 mg/kg did not affect it significantly. In contrast systemic administration of TMB, nor-TMB and lidocaine at 10 mg/kg had no significant effect. Furthermore, local administration of TMB (30 mg/kg) and lidocaine (10 mg/kg) significantly reduced plasmatic extravasation. In conclusion, intracolonic treatment with TMB and nor-TMB improved acute experimental TNBS-induced colitis in rat and these effects could be explained by their local anesthetic activity.

[Effects of trimebutine on colonic propulsion in mice].

Effects of oral administration of trimebutine on colonic propulsion in conscious mice were studied by measuring the time required to evacuate a bead which had been inserted into the colon, and compared with those of metoclopramide and domperidone. In normal animals, trimebutine (10 and 50 mg/kg), metoclopramide (50 mg/kg) and domperidone (50 mg/kg) had no effect on the bead evacuation. Metoclopramide and domperidone at 30 mg/kg showed no effect on the delay of colonic propulsion induced by clonidine, while trimebutine (10 and 30 mg/kg) restored the delay significantly. Trimebutine also showed restoration of the delay induced by loperamide. On the acceleration of the propulsion induced by neostigmine, trimebutine (10 and 30 mg/kg) showed an inhibition. In addition, trimebutine (3-30 mg/kg) dose-dependently suppressed the development of soft feces and/or diarrhea induced by neostigmine. According to the results, it is concluded that trimebutine produces both acceleration and inhibition on the colonic propulsion in mice.

Preparation, characterization and taste-masking properties of polyvinylacetal diethylaminoacetate microspheres containing trimebutine.

The objectives of this study were to produce acid soluble, polyvinylacetal diethylaminoacetate (AEA) microspheres containing trimebutine (as maleate), using a water-in-oil-in-water (w/o/w) emulsion solvent evaporation method, to characterize their in-vitro release properties, and to evaluate the taste-masking potential of this formulation in human volunteers. The pH of the external aqueous phase was the critical factor in achieving a high loading efficiency for trimebutine in the microencapsulation process; nearly 90% (w/w) loading efficiency was obtained at above pH 10. Trimebutine was completely released from AEA microspheres within 10 min in a dissolution test at pH 1.2, simulating conditions in the stomach, whereas at pH 6.8, the pH in the mouth, only small quantities of trimebutine were released in the initial 1-2 min. The results of a gustatory sensation test in healthy volunteers confirmed the taste-masking effects of the AEA microspheres. Finally, an attempt was made to encapsulate the salts of other basic drugs (lidocaine, imipramine, desipramine, amitriptyline, promethazine and chlorpheniramine) into AEA microspheres using the w/o/w emulsion evaporation method. The loading efficiencies were ranked in almost inverse proportion with the solubility of the drugs in the external aqueous phase. This study demonstrated the possibility of masking the taste of salts of basic drugs by microencapsulation with AEA using a w/o/w emulsion solvent evaporation method.

Influence of trimebutine on inflammation- and stress-induced hyperalgesia to rectal distension in rats.

The effects of trimebutine and its major metabolite, N-desmethyltrimebutine on inflammation- and stress-induced rectal hyperalgesia have been evaluated in rats fitted with electrodes implanted in the longitudinal striated muscle of the abdomen. Intermittent rectal distension was performed before and 3 days after induction of rectal inflammation by local infusion of trinitrobenzenesulphonic acid (in ethanol). Stress consisted of 2h partial restraint and rectal distension was performed before and 30min after the end of the partial restraint session. The animals were treated intraperitoneally with trimebutine or desmethyltrimebutine (5, 10 or 20mgkg(-1)) or vehicle 15min before rectal distension. Naloxone (1mgkg(-1)) or saline was injected subcutaneously before trimebutine and desmethyltrimebutine. Before treatment trimebutine at the highest dose (20mgkg(-1)) reduced the abdominal response to rectal distension for the highest volume of distension (1.6mL) whereas desmethyltrimebutine was inactive. After rectocolitis the abdominal response to rectal distension was enhanced and trimebutine at 5mgkg(-1) reduced and at 10 mgkg(-1) suppressed inflammation-induced hyperalgesia, an effect reversed by naloxone. Desmethyltrimebutine was inactive. Stress-induced hypersensitivity was attenuated or suppressed, or both, by trimebutine and desmethyltrimebutine at doses of 5, 10 or 20mgkg(-l); greater efficacy was observed for desmethyltrimebutine and the effects were not reversed by naloxone. It was concluded that trimebutine and desmethyltrimebutine are active against inflammation- and stress-induced rectal hyperalgesia but act differently. The effect of trimebutine on inflammation-induced hyperalgesia is mediated through opioid receptors.

The effect of trimebutine maleate on gastric emptying in patients with non-ulcer dyspepsia.

The study was designed to investigate the effect of trimebutine maleate, a drug used in both hyperkinetic and hypokinetic motility disorders, on gastric emptying in patients with non-ulcer dyspepsia having prolonged gastric emptying rates and to compare the parameters used for the determination of the lag period observed during the emptying of solid foods from the stomach. Gastric emptying was measured by the radionuclide technique. Twenty normal volunteers and 43 patients with non-ulcer dyspepsia participated in the study. Radionuclide imaging was performed by using a solid meal labeled with 99mTc-tin colloid. Of the patients with non-ulcer dyspepsia, 20 had prolonged gastric emptying. They were given three weeks of oral treatment with trimebutine maleate and had their radionuclide gastric emptying study repeated. Treatment with trimebutine maleate resulted in reduction in duration of the lag period and less retention of food at 100 minutes (p < 0.0005). After treatment with trimebutine maleate, no significant difference has been observed in the mean symptom score of patients with prolonged gastric emptying. Among the parameters used for the determination of the lag period, lag period determined by a mathematical equation (TLAG) has been found to be longer than the lag period determined by visual inspection of the images (VLAG) and there was correlation between the two parameters when the lag time was short.

[Effect of trimebutine on the plasma postprandial release of gastrointestinal hormones in the dog]. / Effet de la trimébutine sur la libération plasmatique postprandiale d'hormones gastrointestinales chez le chien.

The injection of trimebutine induces in the dog an increase of plasma motilin during the fasting period as well as after a meal. We studied the effect of trimebutine on several gastrointestinal hormones released into the circulation by the ingestion of a meal. The intravenous administration of trimebutine (10 mg/kg/h) in 4 dogs abolished the postprandial increase in plasma gastrin, pancreatic polypeptide, insulin, glucagon and GIP. Trimebutine could therefore, by its effects on various regulatory peptides, influence several digestive functions. Its mode of action could probably involves complex mechanisms, including paradoxical effects. The possibility that motilin is a mediator of the trimebutine effect on small bowel smooth muscle is discussed.

Effects of orally vs. parenterally administrated trimebutine on gastrointestinal and colonic motility in dogs.

The influence of oral administration and intravenous infusion of trimebutine maleate (TMB) and N-desmethyl TMB (NDTMB), its main metabolite, was investigated in conscious dogs equipped with chronically implanted strain-gauges. In fasted dogs, TMB (10 to 20 mg/kg per os) delayed the occurrence of the next activity front on both stomach and duodenum by reinforcing the duration of the intestinal phase II. It also induced the occurrence of an additional migrating phase III. These effects were associated with a colonic stimulation generally followed by an inhibition. Comparatively NDTMB at similar dosages disrupted the antral cyclic phases which were replaced by continuous low amplitude contractions during 5-7 h. The MMC pattern persisted with a significant increase in the duration of phase II, and the colonic motility was inhibited during 4.3 to 6.7 h. Infused intravenously at a dose of 3 mg X kg-1 X h-1, TMB immediately inhibited the gastric cyclic contractions in fasted dogs. As for the oral route, the small bowel exhibited an increase in the duration of phase II frequently associated with the occurrence of an additional phase III. Furthermore an inhibition of the colonic motility was observed only at the end of the infusion and lasted at least 4 h. At similar dosage NDTMB had less pronounced inhibitory effects on gastric activity fronts and in contrast with TMB, the inhibitory effect on the colonic motility was observed as soon as the infusion of NDTMB started. These data demonstrate that orally administered TMB stimulates intestinal motility as previously described for i.v. route but in contrast to parenteral administration also stimulates antral and colonic motility.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of trimebutine on the motility of the normal human small intestines: mechanism of action]. / Effet de la trimébutine sur la motricité de l'intestin grêle proximal chez l'homme normal: mécanisme d'action.

The effects of intravenous trimebutine (TMB) on duodenojejunal motility were investigated in normal subjects in fed and fasted states. The motility was recorded manometrically. In the fasting state TMB 100 mg, 25 min after a spontaneous phase 3 (P3) constantly induced a premature P3. The mean period (means +/- SE) of the migrating motor complex (MMC) cycle decreased from 84 +/- 10.9 to 32.5 +/- 1.0 min. TMB 50 mg, 3 and 25 min after a spontaneous P3 did not significantly modify the periodicity of MMC. TMB 100 mg initiated P3-like activity in post-prandial state. Previous administration of a low dose of naloxone suppressed the stimulating action of TMB. After a TMB injection the motilin plasma level did not vary; a brief increated of PP plasma level was observed. It may be concluded that in the human small intestine TMB included a typical modification of the motility pattern. Opiate receptors might be involved.

[Pharmacokinetics and bioequivalence of trimebutine dispersive tablet in healthy subjects].

AIM: To develop an HPLC-ESI-MS assay for determination of trimebutine in human plasma and to investigate the pharmacokinetics and bioequivalence of two trimebutine tablets in human. METHODS: After being made alkaline with saturated sodium bicarbonate, plasma was extracted by cyclohexane and separated by HPLC on a reversed-phase C18 column with a mobile phase of 10 mmol x L(-1) ammonium acetate buffer solution (pH 3.5)-methanol (18:82). HPLC-ESI-MS was performed in the selected ion monitoring (SIM) mode using target ions at m/z 388 for trimebutine and m/z 280 for the internal standard (sibutramine, IS). The fragmentor voltage was 50 V. A randomized cross-over design was performed in 20 healthy volunteers. In the two study periods, a single 100 mg dose of each tablet was administered to each volunteer. RESULTS: Calibration curve was linear over the range of 0.3 - 150 microg x L(-1). The main pharmacokinetic parameters of T1/2, Tmax and Cmax were (9.2 +/- 2.8) h, (1.0 +/- 0.3) h and (40 +/- 20) microg x L(-1) for the reference tablet; (9.2 +/- 2.3) h, (0.9 +/- 0.4) h and (41 +/- 20) microg x L(-1) for the test tablet. The relative bioavalability of the test tablet was (97 +/- 13)%. The results of variance analysis and two one-sided t-test showed that there was no significant difference between the two formulations in the AUC and Cmax. CONCLUSION: The assay was proved to be sensitive, accurate and convenient. The two formulations were bioequivalent.

[Effects of trimebutine on motility of the small intestine in humans]. / Effets de la trimébutine sur la motricité de l'intestin grêle chez l'homme.

Trimebutine maleate induces a specific motor response in the human proximal small bowel: except for the few minutes lapse following the occurrence of a spontaneous phase 3, an intravenous injection of 100 mg trimebutine systematically produces, in fed or fasted state, a systemic propagated activity analogous to the spontaneous phase 3 of the migrating motor complex. In lower doses, this effect is not observed. The intraduodenal administration of a high dose (600 mg) induces a similar response to that observed after intravenous injection. Trimebutine possibly acts as a stimulator of peripheral receptors of the enkephalinergic nervous system. Theoretically, these results may result in recommending the therapeutic use of trimebutine in intestinal motility disorders where disappearance or depletion of phase 3 are observed. However, information is still lacking about the relationship between therapeutic activity and the effects on intestinal motility in pathological states.

[Effects of trimebutine on intestinal motility in dogs]. / Effets de la trimébutine sur les motricités digestives chez le chien.

The effects of intravenous, oral, intracerebroventricular and local intra-arterial administration of trimebutine were investigated in dogs whose digestive tract had been fitted with electrodes and strain gauge transducers. In fasted conscious dogs, trimebutine (5 mg/kg) stimulated small bowel motility with induction of a propagated phase of regular spiking activity. This stimulation was associated with weak inhibition of gastric motility and a biphasic response of the colon characterized by stimulation followed by inhibition. By the oral route, trimebutine (20 mg/kg) stimulated gastrointestinal motility. The duration of the intestinal migrating phase 2 was increased whereas an additional migrating phase 3 developed. These effects were associated with an increase in colonic contractions lasting two hours. The stimulating effect of trimebutine (phase 3) on intestinal motility was not reproduced after intracerebroventricular administration and was abolished by previous intravenous, but not intraventricular, administration of naloxone. The local effects of trimebutine on the circular muscle of canine gastrointestinal tract were studied after close intra-arterial injection in anesthetized dogs. Under these conditions, the drug stimulated the resting gut through its neural and direct smooth muscle components while it inhibited the contractions induced by field stimulation. In conclusion, the excitatory effect of trimebutine seems to be mediated by mu or delta receptors while its inhibitory activity might involve kappa opiate receptors.

Effects of trimebutine maleate on colonic motility through Ca²+-activated K+ channels and L-type Ca²+ channels.

The effects of trimebutine maleate (TM) on spontaneous contractions of colonic longitudinal muscle were investigated in guinea pigs. The contractile responses of smooth muscle strips were recorded by an isometric force transducer. Membrane and action potentials were detected by an intracellular microelectrode technique. The whole-cell patch clamp recording technique was used to record the changes in large conductance Ca(2+)-activated K(+) (BK(ca)) and L-type Ca(2+) currents in colonic smooth muscle cells. At high concentrations (30, 100, and 300 µM), TM inhibited the amplitude of spontaneous contractions. At low concentrations (1 and 10 µM), TM attenuated the frequency and tone of smooth muscle strips, whereas TM had no influence on the amplitude of spontaneous contractions. TM depolarized the membrane potentials, but decreased the amplitude and frequency of action potentials at high concentrations. TM inhibited BK(ca) and L-type Ca(2+) currents in a dose-dependent manner. In the presence of the BK(ca) channel opener, NS1619, TM also inhibited BK(ca) currents. Bayk8644, a L-type Ca(2+) channel opener, increased L-type Ca(2+) currents. This augmentation was also attenuated by TM. These results suggest that TM attenuates intestinal motility through inhibition of L-type Ca(2+) currents, and depolarizes membrane potentials by reducing BK(ca) currents. Thus, TM may be a multiple-ion channel regulator in the gastrointestinal tract.