Rescue of Familial Lecithin:Cholesterol Acyltranferase Deficiency Mutations with an Allosteric Activator.

Lecithin:cholesterol acyltransferase (LCAT) deficiencies represent severe disorders characterized by aberrant cholesterol esterification in plasma, leading to life-threatening conditions. This study investigates the efficacy of Compound 2, a piperidinyl pyrazolopyridine allosteric activator that binds the membrane-binding domain of LCAT, in rescuing the activity of LCAT variants associated with disease. The variants K218N, N228K, and G230R, all located in the cap and lid domains of LCAT, demonstrated notable activity restoration in response to Compound 2. Molecular dynamics simulations and structural modeling indicate that these mutations disrupt the lid and membrane binding domain, with Compound 2 potentially dampening these structural alterations. Conversely, variants such as M252K and F382V in the cap and α/ß-hydrolase domain, respectively, exhibited limited or no rescue by Compound 2. Future research should prioritize in vivo investigations that would validate the therapeutic potential of Compound 2 and related activators in familial LCAT deficiency patients with mutations in the cap and lid of the enzyme. SIGNIFICANCE STATEMENT: Lecithin:cholesterol acyltranferase (LCAT) catalyzes the first step of reverse cholesterol transport, namely the esterification of cholesterol in high density lipoprotein particles. Somatic mutations in LCAT lead to excess cholesterol in blood plasma and, in severe cases, kidney failure. In this study, we show that recently discovered small molecule activators can rescue function in LCAT-deficient variants when the mutations occur in the lid and cap domains of the enzyme.

Mechanistic Insights into the Activation of Lecithin-Cholesterol Acyltransferase in Therapeutic Nanodiscs Composed of Apolipoprotein A-I Mimetic Peptides and Phospholipids.

The mechanistic details behind the activation of lecithin-cholesterol acyltransferase (LCAT) by apolipoprotein A-I (apoA-I) and its mimetic peptides are still enigmatic. Resolving the fundamental principles behind LCAT activation will facilitate the design of advanced HDL-mimetic therapeutic nanodiscs for LCAT deficiencies and coronary heart disease and for several targeted drug delivery applications. Here, we have combined coarse-grained molecular dynamics simulations with complementary experiments to gain mechanistic insight into how apoA-Imimetic peptide 22A and its variants tune LCAT activity in peptide-lipid nanodiscs. Our results highlight that peptide 22A forms transient antiparallel dimers in the rim of nanodiscs. The dimerization tendency considerably decreases with the removal of C-terminal lysine K22, which has also been shown to reduce the cholesterol esterification activity of LCAT. In addition, our simulations revealed that LCAT prefers to localize to the rim of nanodiscs in a manner that shields the membrane-binding domain (MBD), αA-αA', and the lid amino acids from the water phase, following previous experimental evidence. Meanwhile, the location and conformation of LCAT in the rim of nanodiscs are spatially more restricted when the active site covering the lid of LCAT is in the open form. The average location and spatial dimensions of LCAT in its open form were highly compatible with the electron microscopy images. All peptide 22A variants studied here had a specific interaction site in the open LCAT structure flanked by the lid and MBD domain. The bound peptides showed different tendencies to form antiparallel dimers and, interestingly, the temporal binding site occupancies of the peptide variants affected their in vitro ability to promote LCAT-mediated cholesterol esterification.

Gliflozins, sucrose and flavonoids are allosteric activators of lecithin-cholesterol acyltransferase.

Lecithin-cholesterol acyltransferase (LCAT) serves as a pivotal enzyme in preserving cholesterol homeostasis via reverse cholesterol transport, a process closely associated with the onset of atherosclerosis. Impaired LCAT function can lead to severe LCAT deficiency disorders for which no pharmacological treatment exists. LCAT-based therapies, such as small molecule positive allosteric modulators (PAMs), against LCAT deficiencies and atherosclerosis hold promise, although their efficacy against atherosclerosis remains challenging. Herein we utilized a quantitative in silico metric to predict the activity of novel PAMs and tested their potencies with in vitro enzymatic assays. As predicted, sodium-glucose cotransporter 2 (SGLT2) inhibitors (gliflozins), sucrose and flavonoids activate LCAT. This has intriguing implications for the mechanism of action of gliflozins, which are commonly used in the treatment of type 2 diabetes, and for the endogenous activation of LCAT. Our results underscore the potential of molecular dynamics simulations in rational drug design.

Pre-cervical ripening and hygroscopic cervical dilators in pre-labor induction.

INTRODUCTION: Induction of labor (IOL) is becoming a universal topic in Obstetrics, when the risk of continuing a pregnancy outweighs the benefits. Preinduction is a more recent tool to prepare the cervix when the BISHOP-score is low. About one-third of IOL cases require cervical ripening, which is the physical softening, thinning, and dilation of the cervix in preparation for labor and birth. We report a single center experience regarding the use of hygroscopic dilators in the pre-labor phase to obtain cervical ripening before labor induction. MATERIALS & METHODS: We conducted a retrospective observational study comparing patient records from the Gynecology and Obstetrics Unit in "Santo Stefano" Hospital in Prato, Tuscany. The inclusion criteria for participants were women who had undergone pre-labor induction because of a BISHOP-score < 3. The gestational age of all the pregnant women was at term (> 37 weeks). RESULTS: From January 2022 to April 2022, a total of 581 women delivered at term of gestational age at the Gynecology and Obstetrics Unit in "Santo Stefano" Hospital. Cervical ripening was necessary for 82 women with a Bishop score < 3 and hygroscopic cervical dilators were used in 35/82 (42.7%) patients. All patients showed a change in Bishop-score upon removal of the dilators. All 35 patients (100%) reported an increase in terms of consistency and dilation of the cervix but not in terms of length. None of the patients reported discomfort during the 24 h that they kept the hygroscopic dilators in place. No patients reported uterine tachysystole on cardiotocographic tracing, vaginal bleeding, rupture of membranes or cervical tears. CONCLUSIONS: Our results are in line with those in the literature, demonstrating the validity of hygroscopic dilators in cervical maturation of pregnancies at term and their efficacy was again highlighted in terms of both maternal and fetal safety and patient satisfaction.

Oral low-dose dipyridamole protects from intravenous high-dose dipyridamole-induced ischemia. A stress echocardiographic study.

Pulse ischemia-dependent submaximal increase in adenosine levels in plasma and in the interstitium is believed to mediate the phenomenon of ischemic preconditioning of the heart, by the interaction with the specific A1 and A3 receptors on myocytes. The aim of the study was to evaluate the effects of chronic oral treatment with dipyridamole (75 mg twice a day for 5 days) in coronary artery disease (CAD) patients with positive echocardiographic stress test with high-dose dipyridamole (DET). We evaluated positivity to DET, adenosine plasma levels in 12 patients treated with dipyridamole in comparison to eight patients treated with placebo. After oral administration of dipyridamole we observed a significant reduction in the number of patients positive to DET (5/12; P=0.02), a pulse increase in adenosine plasma levels (from 220+/-55 to 450+/-70 nmol/l), without any significant haemodynamic effects. Our results suggest that dipyridamole, administered orally at a low dose, but sufficient to increase adenosine plasma level, was able to prevent myocardial ischemia induced by high-dose dipyridamole echo-stress test in CAD patients.

Excess body weight and increased Breslow thickness in melanoma patients: a retrospective study.

Excess body weight has been shown to increase the risk for development of several common cancers, such as postmenopausal breast, colon, endometrium, kidney, and esophagus cancers. The main aim of the present study was to investigate the potential relationship between excess body weight, assessed in terms of BMI, and Breslow thickness in 605 patients affected by primary cutaneous melanoma. Particularly, we evaluated the occurrence of thick melanoma (>1 mm) in overweight compared with nonoverweight patients. The effect of BMI (≥25 vs. <25 kg/m2) on the risk of having a diagnosis of thick melanoma was estimated in terms of odds ratio (OR) by logistic regression analysis, adjusted for age, sex, and histological type. Significant differences in overweight versus nonoverweight patients were found with respect to sex distribution. In fact, the occurrence of thick melanoma was greater in overweight women than in nonoverweight women (OR=1.64). When the analysis was restricted to postmenopausal women, the corresponding OR increased further to 2.50. In conclusion, a positive association between excess body weight and the risk of thick melanoma was found only in female patients. On stratifying patients into subgroups, the relationship between the risk of being diagnosed with a thick melanoma (>1.0 mm) and overweight status (BMI≥25 kg/m2) was significantly affected by both sex and menopausal status. Despite limitations because of both the study design and the relatively small numbers of patients in certain subgroups, overweight status may be associated with an increased Breslow thickness in postmenopausal women.

Amniocentesis in the third trimester of pregnancy.

BACKGROUND: Amniocentesis in the third trimester, which reduces risks of procedure-related miscarriage but still allows termination of affected fetuses, may be applicable in some pregnancies. The implications of deferring amniocentesis include complications, delivery before the test and increased amniotic fluid culture failure rates. We investigated the indications, complications, karyotype results and laboratory failure rates of third-trimester amniocentesis. METHODS: We studied all women who underwent third-trimester amniocentesis from 2000 to 2006. Data were collected from ultrasound databases, computerised records and individual chart review. RESULTS: We reviewed 165 pregnancies that underwent amniocenteses after 28 weeks. Median maternal age at amniocentesis was 32 years and median gestation, 32(+2) weeks. Indications included malformation (60/165), soft markers (37/165), maternal request (12/165), and positive screening test (11/165). Of the 49 women(29.7%) who declined second-trimester amniocentesis, 24.5% had twins and 38.8%, malformations. Amniocentesis was not offered to 116 women: 57/116 (49.1%) third-trimester referrals, 25/116 (21.5%) diagnosed late and the remainder, low-risk indications. Fetal karyotype was abnormal in 17 cases (10.3%). Seven women who initially declined amniocentesis had abnormal results compared with one advised to have late amniocentesis. Culture failure rate was 9.7%, however results were obtained by Quantitative fluorescent polymerase chain reaction (QF-PCR) from 164/165 samples. Complication rate was 1.2%. CONCLUSION: For late diagnoses and for low-risk indications, third-trimester amniocentesis is an acceptable option, especially when utilising QF-PCR with cytogenetic culture.