Quadriceps muscle properties in rheumatoid arthritis: insights about muscle morphology, activation and functional capacity.

BACKGROUND: Rheumatoid arthritis (RA) is an inflammatory and chronic autoimmune disease that leads to muscle mass loss and functional capacity impairment, potentiated by physical inactivity. Despite evidences demonstrate neuromuscular impairments in RA patients, aging effects may have masked the results of similar previous studies. The aim of study was to verify (i) the effects of RA on functional capacity and muscle properties in middle-aged patients and (ii) the association between age, clinical characteristics, quadriceps muscle properties and functional capacity. METHODS: Thirty-five RA women and 35 healthy age-matched women were compared with the following outcomes: (i) physical activity level through the International Physical Activity Questionnaire (IPAQ); (ii) timed-up and go (TUG) test; (iii) isometric knee extensor muscular strength; and (iv) vastus lateralis muscle activation and muscle architecture (muscle thickness, pennation angle and fascicle length) during an isometric test. An independent Student t-test and partial correlation (controlled by physical activity levels) were performed, with p < 0.05. RESULTS: Compared with healthy women, RA presented (i) lower physical activity level (- 29.4%; p < 0.001); (ii) lower isometric knee extensor strength (- 20.5%; p < 0.001); (iii) lower TUG performance (- 21.7%; p < 0.001); (iv) smaller muscle thickness (- 23.3%; p < 0.001) and pennation angle (- 14.1%; p = 0.011). No differences were observed in muscle activation and fascicle length. Finally, the correlation demonstrated that, with exception of TUG, muscle strength and muscle morphology were not associated with age in RA, differently from healthy participants. CONCLUSION: Middle-aged RA patients' impairments occurred due to the disease independently of the aging process, except for functional capacity. Physical inactivity may have potentiated these losses.

Quadriceps muscle properties in rheumatoid arthritis: insights about muscle morphology, activation and functional capacity

Abstract Background: Rheumatoid arthritis (RA) is an inflammatory and chronic autoimmune disease that leads to muscle mass loss and functional capacity impairment, potentiated by physical inactivity. Despite evidences demonstrate neuromuscular impairments in RA patients, aging effects may have masked the results of similar previous studies. The aim of study was to verify (i) the effects of RA on functional capacity and muscle properties in middle-aged patients and (ii) the association between age, clinical characteristics, quadriceps muscle properties and functional capacity. Methods: Thirty-five RA women and 35 healthy age-matched women were compared with the following outcomes: (i) physical activity level through the International Physical Activity Questionnaire (IPAQ); (ii) timed-up and go (TUG) test; (iii) isometric knee extensor muscular strength; and (iv) vastus lateralis muscle activation and muscle architecture (muscle thickness, pennation angle and fascicle length) during an isometric test. An independent Student t-test and partial correlation (controlled by physical activity levels) were performed, with p < 0.05. Results: Compared with healthy women, RA presented (i) lower physical activity level (- 29.4%; p < 0.001); (ii) lower isometric knee extensor strength (- 20.5%; p < 0.001); (iii) lower TUG performance (- 21.7%; p < 0.001); (iv) smaller muscle thickness (- 23.3%; p < 0.001) and pennation angle (- 14.1%; p = 0.011). No differences were observed in muscle activation and fascicle length. Finally, the correlation demonstrated that, with exception of TUG, muscle strength and muscle morphology were not associated with age in RA, differently from healthy participants. Conclusion: Middle-aged RA patients' impairments occurred due to the disease independently of the aging process, except for functional capacity. Physical inactivity may have potentiated these losses.(AU)

rHDL administration increases reverse cholesterol transport in mice, but is not additive on top of ezetimibe or cholestyramine treatment.

OBJECTIVE: Promoting reverse cholesterol transport (RCT) is a major atheroprotective property of HDL. The present study explored the effect of stimulating the first step of RCT (cholesterol efflux from macrophages) alone or in combination with stimulating the last step of RCT (fecal sterol excretion). METHODS AND RESULTS: Reconstituted HDL (rHDL) was injected into wild-type mice either with or without administration of the cholesterol absorption inhibitor ezetimibe or the bile acid sequestrant cholestyramine. Single dose administration of rHDL (100 mg apoA-I/kg) resulted in an early (4 h) increase in plasma free cholesterol levels (p < 0.001), without affecting hepatic cholesterol levels or fecal mass sterol excretion. rHDL injection also increased [(3)H]cholesterol appearance in plasma at an early time-point (4 h) after intraperitoneal administration of [(3)H]cholesterol-labeled mouse macrophage foam cells and fecal radioactivity excretion indicating completed RCT was increased by 26% (p < 0.05). Ezetimibe treatment inhibited intestinal cholesterol absorption by 74% (p < 0.01), but also the bile acid sequestrant cholestyramine decreased cholesterol absorption significantly (24%, p < 0.01). Consequently, ezetimibe increased RCT 2.1-fold (p < 0.001) primarily within fecal neutral sterols, while cholestyramine increased RCT by 3.6-fold (p < 0.001), primarily within bile acids (p < 0.001), but also within neutral sterols (p < 0.001). However, no additive effects of both intestinal sterol uptake inhibitors were observed on top of rHDL administration. CONCLUSION: These data demonstrate that increasing the first step of RCT by rHDL administration results in transient cholesterol mobilization from macrophages to plasma. This effect is not further enhanced by stimulating the last step of RCT, fecal sterol excretion.

Differential regulation of bile acid and cholesterol metabolism by the farnesoid X receptor in Ldlr -/- mice versus hamsters.

Modulating bile acid synthesis has long been considered a good strategy by which to improve cholesterol homeostasis in humans. The farnesoid X receptor (FXR), the key regulator of bile acid synthesis, was, therefore, identified as an interesting target for drug discovery. We compared the effect of four, structurally unrelated, synthetic FXR agonists in two fat-fed rodent species and observed that the three most potent and selective agonists decreased plasma cholesterol in LDL receptor-deficient (Ldlr (-/-)) mice, but none did so in hamsters. Detailed investigation revealed increases in the expression of small heterodimer partner (Shp) in their livers and of intestinal fibroblast growth factor 15 or 19 (Fgf15/19) in mice only. Cyp7a1 expression and fecal bile acid (BA) excretion were strongly reduced in mice and hamsters by all four FXR agonists, whereas bile acid pool sizes were reduced in both species by all but the X-Ceptor compound in hamsters. In Ldlr (-/-) mice, the predominant bile acid changed from cholate to the more hydrophilic ß-muricholate due to a strong repression of Cyp8b1 and increase in Cyp3a11 expression. However, FXR agonists caused only minor changes in the expression of Cyp8b1 and in bile acid profiles in hamsters. In summary, FXR agonist-induced decreases in bile acid pool size and lipophilicity and in cholesterol absorption and synthesis could explain the decreased plasma cholesterol in Ldlr (-/-) mice. In hamsters, FXR agonists reduced bile acid pool size to a smaller extent with minor changes in bile acid profile and reductions in sterol absorption, and consequently, plasma cholesterol was unchanged.

Effect of dalcetrapib, a CETP modulator, on non-cholesterol sterol markers of cholesterol homeostasis in healthy subjects.

OBJECTIVE: Subjects with high HDL-C show elevated plasma markers of cholesterol absorption and reduced markers of cholesterol synthesis. We evaluated the effect of dalcetrapib, a cholesteryl ester transfer protein modulator, on markers of cholesterol homeostasis in healthy subjects. METHODS: Dalcetrapib was administered daily with or without ezetimibe in a randomized, open-label, crossover study in 22 healthy subjects over three 7-day periods: dalcetrapib 900 mg, ezetimibe 10mg, dalcetrapib 900 mg plus ezetimibe 10mg. Plasma non-cholesterol sterols lathosterol and desmosterol (cholesterol synthesis markers) and campesterol, ß-sitosterol and cholestanol (intestinal cholesterol absorption markers) were measured. A hamster model was used to compare the effect of dalcetrapib and torcetrapib with or without ezetimibe on these markers and determine the effect of dalcetrapib on cholesterol absorption. RESULTS: Dalcetrapib increased campesterol, ß-sitosterol, and cholestanol by 27% (p = 0.001), 32% (p < 0.001), and 12% (p = 0.03), respectively, in man (non-cholesterol sterol/cholesterol ratio). Dalcetrapib+ezetimibe reduced campesterol by 11% (p = 0.02); ß-sitosterol and cholestanol were unaffected. Lathosterol and desmosterol were unchanged with dalcetrapib, but both increased with ezetimibe alone (56-148%, p < 0.001) and with dalcetrapib + ezetimibe (32-38%, p < 0.001). In hamsters, dalcetrapib and torcetrapib increased HDL-C by 49% (p = 0.04) and 72% (p = 0.003), respectively. Unlike torcetrapib, dalcetrapib altered cholesterol homeostasis towards increased markers of cholesterol absorption; cholesterol synthesis markers were unaffected by either treatment. Dalcetrapib did not change plasma (3)H-cholesterol level but increased (3)H-cholesterol in plasma HDL vs non-HDL, after oral dosing of labeled cholesterol. CONCLUSION: Dalcetrapib specifically increased markers of cholesterol absorption, most likely reflecting nascent HDL lipidation by intestinal ABCA1, without affecting markers of synthesis.

Characterization of post-surgical alterations in the bile duct-cannulated rat.

The bile duct-cannulated (BDC) rat is a standard animal model used in ADME experiments. The aim of this study was to investigate post-surgical alterations that are relevant to ADME investigations in BDC rats compared with sham- and non-operated animals. Water and food intake was reduced in the animals' post-surgery. This led to a lower body weight in operated animals. In BDC animals, aspartate aminotransferase (AST) levels in plasma were transiently elevated and total bile acid levels were reduced. Alpha(1)-acid glycoprotein (AGP) in plasma and the concentration of bile components in bile were elevated. Histopathology showed inflammation in the area of the cannulation between the liver and the small intestine. A microarray-based gene expression and RTq-PCR analysis identified altered expression for several genes involved in drug disposition including the down-regulation of cytochrome P450 enzymes. This led to reduced cytochrome P450 content in the liver and lower metabolic activity in microsomes from BDC and sham-operated rats compared with naïve animals. The results of the study suggest that the post-surgical inflammation leads to physiological changes relevant for drug absorption and disposition. These alterations should be accounted for in the interpretation of ADME studies in BDC animals.

Studies in mice, hamsters, and rats demonstrate that repression of hepatic apoA-I expression by taurocholic acid in mice is not mediated by the farnesoid-X-receptor.

It is claimed that apoA-I expression is repressed in mice by cholic acid (CA) and its taurine conjugate, taurocholic acid (TCA) via farnesoid X receptor (FXR) activation. We measured apoA-I expression in mice, hamsters, and rats treated with highly potent and selective synthetic FXR agonists or with TCA. All of the synthetic agonists bound to FXR with high affinity in a scintillation proximity assay. However, TCA did not compete with the radioligand up to the highest concentration used (100 µM). The C-site regulatory region of apoA-I, through which FXR has been reported to regulate its expression, is completely conserved across the species investigated. In both male and female human apoA-I-transgenic mice, we reproduced the previously reported strong inhibition of human apoA-I expression upon treatment with the typical supraphysiological dose of TCA used in such studies. However, in contrast to some previous reports, TCA did not repress murine apoA-I expression in the same mice. Also, more-potent and -selective FXR agonists did not affect human or murine apoA-I expression in this model. In LDL receptor-deficient mice and Golden Syrian hamsters, selective FXR agonists did not affect apoA-I expression, whereas in Wistar rats, some even increased apoA-I expression. In conclusion, selective FXR agonists do not repress apoA-I expression in rodents. Repression of human apoA-I expression by TCA in transgenic mice is probably mediated through FXR-independent mechanisms.

Discovery of novel and orally active FXR agonists for the potential treatment of dyslipidemia & diabetes.

Herein we describe the synthesis and structure activity relationship of a new class of FXR agonists identified from a high-throughput screening campaign. Further optimization of the original hits led to molecules that were highly active in an LDL-receptor KO model for dyslipidemia. The most promising candidate is discussed in more detail.

Aleglitazar, a new, potent, and balanced dual PPARalpha/gamma agonist for the treatment of type II diabetes.

Design, synthesis, and SAR of novel alpha-alkoxy-beta-arylpropionic acids as potent and balanced PPARalphagamma coagonists are described. One representative thereof, Aleglitazar ((S)-2Aa), was chosen for clinical development. Its X-ray structure in complex with both receptors as well as its high efficacy in animal models of T2D and dyslipidemia are also presented.

Design and biological evaluation of novel, balanced dual PPARalpha/gamma agonists.

An X-ray-guided design approach led to the identification of a novel, balanced class of alpha-ethoxy-phenylpropionic acid-derived dual PPARalpha/gamma agonists. The series shows a wide range of PPARalpha/gamma ratios within a rather narrow structural space. Advanced compounds possess favorable physicochemical and pharmacokinetic profiles and show a high efficacy in T2D and dyslipidemia animal models.

The effect of cholesteryl ester transfer protein overexpression and inhibition on reverse cholesterol transport.

AIMS: Cholesteryl ester transfer protein (CETP) has a well-established role in lipoprotein metabolism, but the effect of its overexpression or inhibition on the efficiency of reverse cholesterol transport (RCT) is unclear. METHODS AND RESULTS: Neither overexpression of CETP nor treatment with CETP inhibitor Torcetrapib of RAW 264.7 macrophages or HepG2 hepatocytes affected cholesterol efflux in vitro. Overexpression of CETP or treatment with Torcetrapib, respectively, stimulated or inhibited HDL cholesteryl ester uptake by HepG2 but not by RAW 264.7 cells. When RAW 264.7 cells transfected with CETP or ATP binding cassette transporter A1 (ABCA1) were injected intraperitoneally into mice, cholesterol egress from macrophages was elevated for ABCA1- but not for CETP-transfected macrophages. Systemic expression of CETP in mice by adenoviral infection stimulated egress of cholesterol to plasma and liver without affecting HDL levels. Treatment with Torcetrapib did not affect appearance of macrophage cholesterol in plasma and liver, but inhibited its excretion into feces. Treatment of hamsters with Torcetrapib led to elevation of HDL cholesterol, an increase in the capacity of plasma to support cholesterol efflux, and increased egress of cholesterol from macrophages to plasma and feces in vivo. CONCLUSION: Both increased (mice study) and decreased (hamster study) CETP activity could result in enhanced RCT.

Methylergometrine poisoning in children: review of 34 cases.

Methylergometrine is often used in the management of the third stage of labor and for treatment of prevention of puerperal hemorrhage. Intoxication in newborns is rare but may lead to severe complications. We reviewed 34 cases of methylergometrine poisoning that occurred in Belgium between 1969 and 1999. Fourteen patients were newborns and 20 were older children. Twenty-nine patients were exposed by the oral route, 3 by the intranasal route, and 2 by the intramuscular route. Oral exposure was associated mostly with gastrointestinal symptoms, but one newborn required mechanical ventilation for apnea. Intramuscular exposure was associated with severe complications, including apnea, coma, and convulsions. We describe the first case of oral methylergometrine poisoning requiring mechanical ventilation and alert physicians that oral exposure to methylergometrine may lead to severe complications.