The Application of Peptide Nucleic Acids (PNA) in the Inhibition of Proprotein Convertase Subtilisin/Kexin 9 (PCSK9) Gene Expression in a Cell-Free Transcription/Translation System.

Proprotein convertase subtilisin/kexin 9 (PCSK9) is a protein that plays a key role in the metabolism of low-density lipoprotein (LDL) cholesterol. The gain-of-function mutations of the PCSK9 gene lead to a reduced number of surface LDL receptors by binding to them, eventually leading to endosomal degradation. This, in turn, is the culprit of hypercholesterolemia, resulting in accelerated atherogenesis. The modern treatment for hypercholesterolemia encompasses the use of biological drugs against PCSK9, like monoclonal antibodies and gene expression modulators such as inclisiran-a short, interfering RNA (siRNA). Peptide nucleic acid (PNA) is a synthetic analog of nucleic acid that possesses a synthetic peptide skeleton instead of a phosphate-sugar one. This different structure determines the unique properties of PNA (e.g., neutral charge, enzymatic resistance, and an enormously high affinity with complementary DNA and RNA). Therefore, it might be possible to use PNA against PCSK9 in the treatment of hypercholesterolemia. We sought to explore the impact of three selected PNA oligomers on PCSK9 gene expression. Using a cell-free transcription/translation system, we showed that one of the tested PNA strands was able to reduce the PCSK9 gene expression down to 74%, 64%, and 68%, as measured by RT-real-time PCR, Western blot, and HPLC, respectively. This preliminary study shows the high applicability of a cell-free enzymatic environment as an efficient tool in the initial evaluation of biologically active PNA molecules in the field of hypercholesterolemia research. This cell-free approach allows for the omission of the hurdles associated with transmembrane PNA transportation at the early stage of PNA selection.

The Effect of PCSK9 Inhibition on the Stabilization of Atherosclerotic Plaque Determined by Biochemical and Diagnostic Imaging Methods.

Atherosclerosis is a multifactorial, progressive, chronic inflammatory disease. Ultrasound and magnetic resonance imaging are the most accurate predictors of atherosclerotic plaque instability (MRI). Cytokines such as osteopontin, osteoprotegerin, and metalloproteinase 9 could be used as the most recent markers to identify and track the efficacy of anti-atherosclerotic therapy. Patients with USG and MRI-verified unstable atherosclerotic plaque were included in the study. Biomarker concentrations were measured and compared before and after PCSK9 inhibitor therapy. Additionally, concentrations prior to treatment were correlated with MRI images of the carotid artery. After treatment with alirocumab, the concentrations of MMP-9 (p < 0.01) and OPN, OPG (p < 0.05) decreased significantly. Furthermore, the results of OPN, OPG, and MMP 9 varied significantly depending on the type of atherosclerotic plaque in the MRI assay. In stable atherosclerotic plaques, the concentrations of OPN and OPG were greater (p < 0.01), whereas the concentration of MMP9 correlated with the instability of the plaque (p < 0.05). We demonstrated, probably for the first time, that alirocumab therapy significantly decreased the serum concentration of atherosclerotic plaque markers. In addition, we demonstrated the relationship between the type of atherosclerotic plaque as determined by carotid MRI and the concentration of these markers.

Exenatide prevents statin-related LDL receptor increase and improves insulin secretion in pancreatic beta cells (1.1E7) in a protein kinase A-dependent manner.

Statins are primary drugs in the treatment of hyperlipidemias. This group of drugs is known for its beneficial pleiotropic effects (e.g., reduction of inflammatory state). However, a growing body of evidence suggests its diabetogenic properties. The culpable mechanism is not completely understood and might be related to the damage to pancreatic beta cells. Therefore, we conceived an in vitro study to explore the impact of atorvastatin on pancreatic islet beta cells line (1.1.E7). We evaluated the influence on viability, insulin, low-density lipoprotein (LDL) receptor, and proprotein convertase subtilisin/kexin type 9 (PCSK9) expression. A significant drop in mRNA for proinsulin and insulin expression was noted. Concurrently, a rise in LDL receptor at the protein level in cells exposed to atorvastatin was noted. Further experiments have shown that exenatide - belonging to glucagon-like peptide 1 (GLP-1) analogs that are used in a treatment of diabetes and known for its weight reducing properties - can alleviate the observed alterations. In this case, the mechanism of action of exenatide was dependent on a protein kinase A pathway. In conclusion, our results support the hypothesis that statin may have diabetogenic properties, which according to our study is related to reduced insulin expression. The concomitant use of GLP-1 receptor agonist seemed to successfully revert insulin expression.

Pleiotropic Effects of PCSK-9 Inhibitors.

Proprotein convertase subtilisin/kexin type 9 (PCSK-9) inhibitors are a group of drugs whose main mechanism of action is binding to the PCSK-9 molecule, which reduces the degradation of the low-density lipoprotein receptor (LDL-R) and, hence, increases the uptake of low-density lipoprotein cholesterol (LDLc) from the bloodstream as well as reducing its concentration. The effectiveness of three monoclonal antibodies, namely, alirocumab (human IgG1/κ monoclonal antibody, genetically engineered in Chinese hamster ovary cells), evolocumab (the first fully human monoclonal antibody), and bococizumab (humanized mouse antibody), in inhibiting the action of PCSK-9 and reducing LDLc levels has been confirmed. The first two, after clinical trials, were approved by the Food and Drug Administration (FDA) and are used primarily in the treatment of autosomal familial hypercholesterolemia and in cases of statin intolerance. They are currently used both as monotherapy and in combination with statins and ezetimibe to intensify therapy and achieve therapeutic goals following the American Heart Association (AHA) and European Society of Cardiology (ESC) guidelines. However, the lipid-lowering effect is not the only effect of action described by researchers that PCSK-9 inhibitors have. This paper is a review of the literature describing the pleiotropic effects of PCSK-9 inhibitors, which belong to a group of drugs that are being increasingly used, especially when standard lipid-lowering therapy fails. The article focuses on activities other than lipid-lowering, such as the anti-atherosclerotic effect and stabilization of atherosclerotic plaque, the anti-aggregation effect, the anticoagulant effect, the antineoplastic effect, and the ability to influence the course of bacterial infections. In this publication, we try to systematically review the current scientific data, both from our own scientific work and knowledge from international publications.

The Effects of Statins on Neurotransmission and Their Neuroprotective Role in Neurological and Psychiatric Disorders.

Statins are among the most widely used drug classes in the world. Apart from their basic mechanism of action, which is lowering cholesterol levels, many pleiotropic effects have been described so far, such as anti-inflammatory and antiatherosclerotic effects. A growing number of scientific reports have proven that these drugs have a beneficial effect on the functioning of the nervous system. The first reports proving that lipid-lowering therapy can influence the development of neurological and psychiatric diseases appeared in the 1990s. Despite numerous studies about the mechanisms by which statins may affect the functioning of the central nervous system (CNS), there are still no clear data explaining this effect. Most studies have focused on the metabolic effects of this group of drugs, however authors have also described the pleiotropic effects of statins, pointing to their probable impact on the neurotransmitter system and neuroprotective effects. The aim of this paper was to review the literature describing the impacts of statins on dopamine, serotonin, acetylcholine, and glutamate neurotransmission, as well as their neuroprotective role. This paper focuses on the mechanisms by which statins affect neurotransmission, as well as on their impacts on neurological and psychiatric diseases such as Parkinson's disease (PD), Alzheimer's disease (AD), vascular dementia (VD), stroke, and depression. The pleiotropic effects of statin usage could potentially open floodgates for research in these treatment domains, catching the attention of researchers and clinicians across the globe.

Tricyclic Antidepressants Modulate Stressed Mitochondria in Glioblastoma Multiforme Cells.

A common feature of solid tumors, including glioblastoma multiforme (GBM), is mitochondrial dysfunction. However, it is reported that the current standard of anti-GBM therapies may potentiate mitochondrial damage and, in effect, support the aggressive character of cancer. As mitochondria are implicated in the modulation of cellular drug sensitivity and chemoresistance mechanisms, activation-stressed mitochondria in GBM cells may represent a new target for anti-GBM therapy that is nontoxic for normal cells. METHODS: As mitochondria are possible targets for antidepressant drugs used as adjuvant therapy in patients with GBM, we examined their influence on mitochondrial volume and activity, reactive oxygen species level, extracellular lactate concentration, and p65 NF-κB gene expression in GBM cells. RESULTS: Our investigation showed, for the first time, that tricyclic antidepressants, imipramine and amitriptyline, partially reverse GBM abnormalities. CONCLUSION: In the light of reported studies, the mitochondrial disturbance observed in glioma cells is a dynamic process that can be reversed or silenced. Moreover, imipramine and amitriptyline are attractive cellular metabolic modulators and can potentially be used to restoring a proper function of mitochondria in GBM cells.

The application of strand invasion phenomenon, directed by peptide nucleic acid (PNA) and single-stranded DNA binding protein (SSB) for the recognition of specific sequences of human endogenous retroviral HERV-W family.

The HERV-W family of human endogenous retroviruses represents a group of numerous sequences that show close similarity in genetic composition. It has been documented that some members of HERV-W-derived expression products are supposed to play significant role in humans' pathology, such as multiple sclerosis or schizophrenia. Other members of the family are necessary to orchestrate physiological processes (eg, ERVWE1 coding syncytin-1 that is engaged in syncytiotrophoblast formation). Therefore, an assay that would allow the recognition of particular form of HERV-W members is highly desirable. A peptide nucleic acid (PNA)-mediated technique for the discrimination between multiple sclerosis-associated retrovirus and ERVWE1 sequence has been developed. The assay uses a PNA probe that, being fully complementary to the ERVWE1 but not to multiple sclerosis-associated retrovirus (MSRV) template, shows high selective potential. Single-stranded DNA binding protein facilitates the PNA-mediated, sequence-specific formation of strand invasion complex and, consequently, local DNA unwinding. The target DNA may be then excluded from further analysis in any downstream process such as single-stranded DNA-specific exonuclease action. Finally, the reaction conditions have been optimized, and several PNA probes that are targeted toward distinct loci along whole HERV-W env sequences have been evaluated. We believe that PNA/single-stranded DNA binding protein-based application has the potential to selectively discriminate particular HERV-W molecules as they are at least suspected to play pathogenic role in a broad range of medical conditions, from psycho-neurologic disorders (multiple sclerosis and schizophrenia) and cancers (breast cancer) to that of an auto-immunologic background (psoriasis and lupus erythematosus).

Time-Dependent Changes in Apoptosis Upon Autophagy Inhibition in Astrocytes Exposed to Oxygen and Glucose Deprivation.

Recent studies have implicated the role of autophagy in brain ischemia pathophysiology. However, it remains unclear whether autophagy activation is protective or detrimental to astrocytes undergoing ischemic stress. This study evaluated the influence of ischemia-induced autophagy on cell death and the course of intrinsic and extrinsic apoptosis in primary cultures of rat cortical astrocytes exposed to combined oxygen-glucose deprivation (OGD). The role of autophagy was assessed by pharmacological inhibition with 3-methyladenine (3-MA). Cell viability was evaluated by measuring LDH release and through the use of the alamarBlue Assay. Apoptosis and necrosis were determined by fluorescence microscopy after Hoechst 33,342 and propidium iodide staining, respectively. The levels of apoptosis-related proteins were analyzed by immunoblotting. The downregulation of autophagy during OGD resulted in decreased cell viability and time-dependent changes in levels of apoptosis and necrosis. After short-term OGD (1, 4 h), cells treated with 3-MA showed higher level of cleaved caspase 3 compared with control cells. This result was consistent with an evaluation of apoptotic cell number by fluorescence microscopy. However, after prolonged exposure to OGD (8, 24 h), the number of apoptotic astrocytes (microscopically evaluated) did not differ or was even lower (as marked by caspase 3) in the presence of the autophagy inhibitor in comparison to the control. A higher level of necrosis was observed in 3-MA-treated cells compared to non-treated cells after 24 h OGD. The downregulation of autophagy caused time-dependent changes in both extrinsic (cleaved caspase 8, TNFα) and intrinsic (cleaved caspase 9) apoptotic pathways. Our results strongly indicate that the activation of autophagy in astrocytes undergoing ischemic stress is an adaptive mechanism, which allows for longer cell survival by delaying the initiation of apoptosis and necrosis.

Superoxide dismutase 1 and glutathione peroxidase 1 are involved in the protective effect of sulodexide on vascular endothelial cells exposed to oxygen-glucose deprivation.

Sulodexide (SDX) is widely used in the treatment of both arterial and venous thrombotic disorders. In addition to its recognized antithrombotic action, SDX has endothelial protective potential, which is independent of the coagulation/fibrinolysis system. However, the detailed molecular mechanisms of the endothelioprotective action of the drug are still unresolved. The aim of the present study was to determine whether treatment with SDX at concentrations of 0.125-0.5 lipase releasing unit (LRU)/ml have on the expression and activity of antioxidant enzymes in ischemic endothelial cells and how these effects might be related to the antiapoptotic properties of SDX. In the present study, human umbilical vein endothelial cells (HUVECs) were subjected to ischemia-simulating conditions (combined oxygen and glucose deprivation, OGD) for 6h to determine the protective effects of SDX. SDX (0.25 and 0.5LRU/ml) in OGD significantly increased the cell viability and prevented mitochondrial depolarization in the HUVECs. Moreover, SDX protected the HUVECs against OGD-induced apoptosis. At concentrations of 0.25 and 0.5LRU/ml, the drug increased both superoxide dismutase 1 (SOD1) and glutathione peroxidase 1 (GPx1) mRNA/protein expression together with a significant attenuation of oxidative stress in ischemic HUVECs. Our findings also demonstrate that an increase in both SOD and GPx activity is involved in the protective effect of SDX on ischemic endothelial cells. Altogether, these results suggest that SDX has a positive effect on ischemia-induced endothelial damage because of its antioxidant and antiapoptotic properties.

TREATMENT WITH CINACALCET INCREASES PLASMA ADIPONECTIN CONCENTRATION IN HEMODIALYZED PATIENTS WITH CHRONIC KIDNEY DISEASE AND SECONDARY HYPERPARATHYROIDISM.

OBJECTIVE: Cinacalcet increases calcium-sensing receptor (CaSR) sensitivity to serum calcium. CaSR is expressed by adipocytes, and adiponectin is an adipokine with antiatherogenic and insulin-sensitizing properties. The aim of this study was to assess the influence of a 3-month cinacalcet regimen on plasma adiponectin concentration in hemodialyzed patients (HDP) with chronic kidney disease (CKD) and secondary hyperparathyroidism (sHPT). METHODS: Plasma adiponectin, advanced oxidation protein products (AOPP), serum interleukin-6 (IL-6) and C-reactive protein (CRP) concentrations were assessed in 65 HDP with sHPT treated with cinacalcet (30-120 mg/day) before the first dose and after 3 months of treatment. RESULTS: There was a significant decrease in serum parathyroid hormone (PTH) concentration: from 1,089 (891-1,286) pg/mL to 775 (574-976) pg/mL after 3 months of treatment (P<.0001). The treatment was associated with a significant (P = .048) increase in plasma adiponectin concentration from 16.9 (14.4-19.5) µg/mL to 17.8 (15.0-20.6) µg/mL. Significant (P = .03) reduction of plasma AOPP concentration was observed from 186.7 (156.7-216.7) pg/mL to 162.6 (141.2-183.9) pg/mL. CONCLUSIONS: A 3-month cinacalcet regimen increased plasma adiponectin concentrations in HDP with sHPT. Increased adiponectinemia in these patients may be related to reduced oxidative stress.

AMP-activated protein kinase is involved in induction of protective autophagy in astrocytes exposed to oxygen-glucose deprivation.

AMP-activated kinase (AMPK) acts as the intracellular ATP depletion sensor, which detects and limits increases in the AMP/ATP ratio. AMPK may be significantly activated under stress conditions that deplete cellular ATP levels such as ischemia/hypoxia or glucose deprivation. Recent studies strongly suggest that AMPK participates in autophagy regulation, but it is not known whether AMPK activated by ischemia regulates autophagy in astrocytes and the consequence of autophagy activation in ischemic astrocytes are unclear. We have investigated the contribution of AMPK to autophagy activation in rat primary astrocyte cultures subjected to ischemia-simulating conditions (combined oxygen glucose deprivation, OGD) and its potential effects on astrocyte damage induced by OGD (1-12 h). The evidence supports the conclusion that AMPK activation at early stages of OGD is involved in induction of protective autophagy in astrocytes. Inhibition of AMPK, either by siAMPKα1 or by compound C, significantly attenuated the expression of autophagy-related proteins and decrease of astrocyte viability following OGD. The findings provide additional data about the role of AMPK in ischemic astrocytes and downstream responses that may be involved in OGD-induced protective autophagy.

A peptide nucleic acid (PNA)-mediated polymerase chain reaction clamping allows the selective inhibition of the ERVWE1 gene amplification.

A new peptide nucleic acid (PNA) mediated QPCR technique for the detection and quantification of the Multiple Sclerosis-Associated Retrovirus (MSRV) belonging to the human endogenous retrovirus-W (HERV-W) family has been developed. The assay utilizes a PNA probe which is fully complementary to the ERVWE1 sequence, another member of the HERV-W family which is closely related to MSRV. Due to its excellent affinity to a completely matched template, PNA probe selectively blocks the amplification of ERVWE1 thus allowing the specific and exclusive detection and quantification of the MSRV as PNA does not interfere with the amplification of MSRV. Using this newly developed method we found that MSRV is predominantly expressed over ERWVE1 in astrocyte-derived U-87 MG cell line but not in human umbilical vein endothelial cells or human placental cells.

Effect of tofacitinib on the phenotype and activity of Caco­2 cells in a model of inflammatory bowel disease.

Reports have indicated that autoimmune bowel disorders affect an increasing number of people on every continent; therefore, it is important to better understand inflammatory bowel disease (IBD) and to explore new treatment options for patients suffering from it. Research has indicated the important role of enterocytes in IBD. Understanding the role of the intestinal epithelium in the pathogenesis of IBD may contribute to a better understanding of the inflammatory processes and aid in the identification of potential therapeutic treatments. The present study aimed to evaluate the effects of tofacitinib on Caco-2 cells cultured in an inflammatory environment induced using cytokines naturally found in patients with ulcerative colitis. Tofacitinib is an orally administered inhibitor of Janus kinases (JAKs) which, by modifying the JAK/STAT signaling pathway, reduces the effect of inflammatory cytokines in the gut. Caco-2 cells were used to model the intestinal epithelium and the culture conditions included the proinflammatory cytokine TNFα and tofacitinib. At the end of the culture period, enzymes involved in oxidative stress (superoxide dismutase 1, catalase, nicotinamide adenine dinucleotide phosphate), a marker of apoptosis (Bcl-2) and a key player in intracellular inflammatory signaling (nuclear factor κB) were assessed by quantitative PCR and western blotting. The in vitro phenotype of Caco-2 cells exposed to an inflammatory environment was observed to be similar to that observed in ulcerative colitis. Notably, tofacitinib was able to improve TNFα-induced changes in an in vitro model of ulcerative colitis, and a reduction in the activity of enzymes associated with oxidative stress was observed. In addition, tofacitinib-induced upregulation of Bcl-2 and claudin-1 may contribute to the beneficial effects of tofacitinib on the intestinal epithelium. Tofacitinib appears to have a protective effect on Caco-2 cells. Notably, in the present study, exposure to TNFα stimulated oxidative stress and apoptotic effects, and disrupted intercellular connectivity. The addition of tofacitinib decreased the activity of the examined parameters of oxidative and apoptotic stress, while increasing the activity of the parameter examined to evaluate the degree of intercellular connections. In conclusion, the inhibitory effects of tofacitinib on oxidative stress, as well as its anti-apoptotic and regenerative effects, provide important information regarding the positive effect of tofacitinib on Caco-2 cells, and therefore constitute potential information about the beneficial effect of the evaluated drug in UC.

The impact of wound-healing assay, phorbol myristate acetate (PMA) stimulation and siRNA-mediated FURIN gene silencing on endogenous retroviral ERVW-1 expression level in U87-MG astrocytoma cells.

PURPOSE: Human endogenous retroviruses (HERVs) are ubiquitous genomic sequences. Normally dormant HERVs, undergo reactivation by environmental factors. This deregulation of HERVs' transcriptional equilibrium correlates with medical conditions such as multiple sclerosis (MS). Here we sought to explore whether exposing the U-87 MG astrocytoma cells to traumatic injury deregulates the expression of HERV-W family member ERVW-1 encoding syncytin-1. We also examined the expression of FURIN gene that is crucial in syncytin-1 synthesis. MATERIAL AND METHODS: Scratch assay was used as a model of cells injury in U-87 MG cells. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blot (WB) and migration assay using Boyden chamber were used. Phorbol 12-myristate 13-acetate (PMA) and small interfering RNA (siRNA) were used for cell stimulation and gene expression inhibition, respectively. RESULTS: Results revealed reduced ERVW-1 expression in cells exposed to injury (p â€‹< â€‹0.05) while GFAP gene - a marker of active astrocytes, was upregulated (p â€‹< â€‹0.01). These findings were confirmed by both WB and RT-qPCR. Expression of FURIN gene was not altered after injury, but cell stimulation by PMA strongly increased FURIN expression, simultaneously downregulating ERVW-1 (p â€‹< â€‹0.01). SiRNA-mediated expression inhibition of ERVW-1 and FURIN influenced the mRNA level for SLC1A5 (ASCT2) - primary syncytin-1 receptor, that was significantly lower. FURIN inhibition by siRNA caused strong upregulation of ERVW-1 expression (p â€‹< â€‹0.01). CONCLUSION: Results showed that mechanical impact affects the expression of endogenous retroviruses in U-87 MG astrocytoma cells by scratch assay. Regulation of FURIN, a crucial enzyme in ERVW-1 turnover may support the therapy of some neurological conditions.

SOCS and diabetes--ups and downs of a turbulent relationship.

Diabetes mellitus is one of the most emerging diseases threatening the present world. Thus, intensive investigations are carried out to better understand the mechanisms occurring in type 1 (T1D) and 2 (T2D) diabetes, and to elaborate more potent methods to fight the disease. In this aspect, the suppressors of cytokine signalling (SOCS) are one of the most studied factors of recent years. SOCS proteins have been discovered as cytokine pathway inhibitors; however, presently, their influence seems wider. Most of the known SOCS proteins are involved in the modulation of the development of insulin resistance, ß-cell failure and eventually T1D and T2D. They are also involved in complications related with diabetes, such as retinopathy, nephropathy and cardiomyopathy. In T1D, SOCS proteins regulate ß-cell mass, mediate resistance to damaging factors and improve pancreatic islet graft survival. Regarding insulin resistance and T2D, SOCS proteins take part in mediating signals produced by diabetogenic substances and regulate insulin receptor functioning, affecting insulin sensitivity. However, not all of the present data are consistent, and thus, further studies are required. Finally, for several pharmacologically active substances of importance regarding the treatment of diabetes, SOCS-modulating properties have already been described. Here, we review the findings of SOCS-diabetes relations of the last decade.

[Hypoparathyroidism: the present state of art]. / Niedoczynnosc przytarczyc: wspólczesny stan wiedzy.

Hypoparathyroidism is a result of reduced secretion or impaired action of parathyroid hormone (PTH). Although considered a rare condition, hypoparathyroidism seems to occur much more frequently than reported. In most cases, hypoparathyroidism remains a complication of neck surgery. However, there is a growing incidence of the autoimmune form of hypoparathyroidism, which may occur in combination with other autoimmune diseases. As parathyroid glands are necessary to sustain life and maintain homeostasis, undetected or misdiagnosed hypoparathyroidism may pose a significant threat to health outcomes, as its presence may increase morbidity and mortality in affected individuals. The clinical consequences of PTH deficiency or impaired receptor action are multidirectional and include nervous hyperexcitability, paresthesias, cramps, tetany, hyperreflexia, convulsions, cataract, weakened tooth enamel, brittle nails and basal ganglia calcifications. In some patients, however, its manifestation may be non-specific, and in these cases the correct diagnosis may be easily missed. Laboratory measurements show hypocalcemia, hyperphosphatemia, and, with the exception of pseudohypoparathyroidism, inappropriately low or undetectable PTH levels. Treatment consists of oral calcium supplementation and vitamin D derivatives. In this review article, we discuss the causes, clinical picture, diagnosis and treatment of hypoparathyroidism and provide the reader with some practical guidance concerning dealing with a patient suffering from this disorder.

Impaired Gonadotropin-Lowering Effects of Metformin in Postmenopausal Women with Autoimmune Thyroiditis: A Pilot Study.

Metformin has been found to reduce elevated gonadotropin levels. Hashimoto's thyroiditis is the most common thyroid disorder in iodine-sufficient areas, and it often develops in postmenopausal women. The aim of this study was to investigate whether autoimmune thyroiditis determines the impact of metformin on gonadotrope secretory function. Two matched groups of postmenopausal women were studied: 35 with euthyroid Hashimoto's thyroiditis (group A) and 35 without thyroid disorders (group B). Throughout the study, all participants received oral metformin (2.55-3 g daily). Plasma glucose, insulin, gonadotropins, estradiol, progesterone, thyrotropin, free thyroid hormones, prolactin, adrenocorticotropic hormone, insulin-like growth factor-1, hsCRP, thyroid peroxidase, and thyroglobulin antibody titers were measured at the beginning of the study and six months later. At entry, both groups differed in thyroid peroxidase antibody titers, thyroglobulin antibody titers, and hsCRP levels. In group A, baseline antibody titers correlated positively with hsCRP and negatively with insulin sensitivity. Although metformin improved glucose homeostasis and reduced hsCRP levels in both study groups, these effects were more pronounced in group B than in group A. Only in group B did metformin decrease FSH levels and tend to reduce LH levels. Thyroid antibody titers and the levels of the remaining hormones did not change throughout the study. The impact of metformin on gonadotropin levels correlated with their baseline values and the degree of improvement in insulin sensitivity, as well as with the baseline and treatment-induced reduction in hsCRP. Moreover, the impact on gonadotropins and insulin sensitivity in group A depended on baseline antibody titers. The obtained results indicate that coexisting autoimmune thyroiditis impairs the gonadotropin-lowering effects of metformin in postmenopausal women.

Vitamin D Status Determines Cardiometabolic Effects of Cabergoline in Women with Elevated Prolactin Levels: A Pilot Study.

Both hyperprolactinemia and vitamin D deficiency appear to be associated with increased cardiometabolic risk. This study aimed to determine whether vitamin D status influences the cardiometabolic effects of cabergoline. The study included three matched groups of women with mild to moderate hyperprolactinemia: vitamin D-naive subjects with vitamin D insufficiency (group A), women with vitamin D deficiency/insufficiency successfully treated with vitamin D (group B), and vitamin D-naive individuals with normal vitamin D status (group C). Plasma prolactin, 25-hydroxyvitamin D, estradiol, glucose homeostasis markers, lipids, high-sensitivity C-reactive protein (hsCRP), fibrinogen, homocysteine, and uric acid, as well as the urinary albumin-to-creatinine ratio (UACR), were measured at study entry and after four months of cabergoline treatment. Although cabergoline reduced prolactin levels and increased estradiol levels in all study groups, the effect on prolactin was more pronounced in groups B and C compared to group A. In groups B and C, the drug enhanced glucose homeostasis, increased HDL-cholesterol, and decreased triglycerides, hsCRP, fibrinogen, homocysteine, uric acid, and UACR. In group A, only insulin resistance, hsCRP, and homocysteine were reduced by cabergoline. The effects on insulin sensitivity, HDL-cholesterol, triglycerides, hsCRP, fibrinogen, homocysteine, uric acid, and UACR were proportional to the decrease in prolactin and baseline levels of 25-hydroxyvitamin D. The obtained results suggest that vitamin D status determines cabergoline's cardiometabolic effects.

Insight into the Evolving Role of PCSK9.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is the last discovered member of the family of proprotein convertases (PCs), mainly synthetized in hepatic cells. This serine protease plays a pivotal role in the reduction of the number of low-density lipoprotein receptors (LDLRs) on the surface of hepatocytes, which leads to an increase in the level of cholesterol in the blood. This mechanism and the fact that gain of function (GOF) mutations in PCSK9 are responsible for causing familial hypercholesterolemia whereas loss-of-function (LOF) mutations are associated with hypocholesterolemia, prompted the invention of drugs that block PCSK9 action. The high efficiency of PCSK9 inhibitors (e.g., alirocumab, evolocumab) in decreasing cardiovascular risk, pleiotropic effects of other lipid-lowering drugs (e.g., statins) and the multifunctional character of other proprotein convertases, were the cause for proceeding studies on functions of PCSK9 beyond cholesterol metabolism. In this article, we summarize the current knowledge on the roles that PCSK9 plays in different tissues and perspectives for its clinical use.