Handbook of experimental pharmacology最新文献

Heparin and related low molecular weight heparin derivatives remain critical drugs for the prevention and treatment of thrombotic conditions. Concerns relating to the stability and sufficiency of the porcine intestinal mucosa supplies from which most heparin is currently derived have spurred an interest in identifying other sources for heparin. Commercial quantities of heparin may be obtained from cow and sheep intestine, and heparin or heparin-like material has been identified in a number of other species. Being biologic in nature, these heparins exhibit unique structural and functional profiles. This chapter summarizes our current understanding of these heparins.

Direct oral anticoagulants (DOACs), also referred to as non-vitamin K oral anticoagulants (NOACs), have revolutionised anticoagulant therapy since their introduction in the late 2000s. These agents - dabigatran (a direct thrombin inhibitor) and the factor Xa inhibitors apixaban, edoxaban, and rivaroxaban - offer more predictable pharmacokinetics, fewer food and drug interactions, and do not typically require routine laboratory monitoring, unlike traditional anticoagulants such as warfarin and heparin. Despite these advantages, laboratory assessment of DOAC activity remains clinically important in specific circumstances, including bleeding, thrombosis during therapy, emergency surgery, renal or hepatic impairment, and suspected non-compliance.This chapter reviews the pharmacology, clinical applications, and laboratory evaluation of DOACs, outlining available assays and their principles. The gold standard for quantification is liquid chromatography-tandem mass spectrometry (LC-MS/MS), though chromogenic anti-Xa and dilute thrombin time (DTT) or ecarin-based assays are more commonly used in clinical laboratories. The impact of DOACs on routine coagulation tests such as PT, APTT, and TT is variable and reagent dependent, underscoring the need for drug-specific calibrators and assay validation.Quality assurance through both internal quality control (IQC) and external quality assessment (EQA) is essential to maintain assay accuracy and reproducibility, in accordance with ISO 15189:2022 standards. Furthermore, DOACs can interfere with other haemostasis assays - including factor assays, antithrombin, and lupus anticoagulant testing - leading to potential diagnostic errors. Recent studies demonstrate that activated charcoal-based reagents, such as DOAC Remove™ and DOAC Stop™, can effectively neutralise DOAC interference in such assays.In conclusion, while DOACs have largely supplanted warfarin in the management of non-valvular atrial fibrillation and venous thromboembolism due to their safety and convenience, laboratory testing retains a critical role in ensuring safe and effective patient management under specific clinical scenarios.

In the late 1990s, the antiplatelet agent clopidogrel, a P2Y12 inhibitor, was introduced into clinical practice. Concurrently, several new methods for assessing platelet function emerged, such as the PFA-100 in 1995, marking the beginning of a sustained expansion in platelet function testing. It soon became apparent that patient responses to clopidogrel varied significantly, with some individuals exhibiting high on-treatment platelet reactivity. This variability prompted discussions around the utility of platelet function testing to tailor antiplatelet therapy. Additionally, such testing was proposed for patients preparing for cardiac surgery to better manage the balance between thrombotic risk before surgery and bleeding risk during the perioperative period. This chapter explores widely used platelet function tests in these contexts, particularly those considered point-of-care (POC) or requiring minimal laboratory processing. It also reviews recent guidelines and clinical trial evidence, building on a previously published chapter, regarding the role and effectiveness of platelet function testing in these clinical scenarios.

Hydrogen sulfide (H₂S) is a gasotransmitter that contributes to the regulation of peripheral nervous system (PNS) function. H₂S is produced by several enzymes whose expression changes under different physiological and pathological conditions, influencing how peripheral neurons respond to environmental and internal signals. H₂S modulates neuronal excitability through its actions on ion channels and through interactions with other gasotransmitters, shaping sensory, autonomic, and pain-related pathways. In autonomic circuits, H₂S adjusts sympathetic and parasympathetic activity. Through these actions, it affects cardiovascular control, gastrointestinal motility, and respiratory rhythm. In pain pathways, H₂S can modulate nociception in either direction, with its effectsshaped by the physiological or pathological state. H₂S participates in multiple pain conditions and contributes to changes in peripheral and spinal processing that influence pain sensitivity. Overall, H₂S influences several components of peripheral neurobiology and represents a potential target for strategies aimed at treating autonomic dysfunction and chronic pain.

Perivascular adipose tissue (PVAT) is a metabolically active, endocrine organ that plays a crucial role in regulating blood vessel tone, endothelial function, vascular smooth muscle cell growth, and proliferation and contributes significantly to the onset and progression of cardiovascular diseases. In a healthy state, PVAT displays anticontractile, anti-inflammatory, and antioxidative properties, which are critical for maintaining vascular homeostasis. However, under certain pathophysiological conditions, PVAT exerts pro-contractile effects by decreasing the production of anticontractile and/or increasing that of pro-contractile factors. In this context, recent studies have identified hydrogen sulfide (H₂S) as a key vascular anti-contractile factor released from PVAT. The enzymes responsible for H₂S biosynthesis are differentially expressed in PVAT, depending on the vascular bed and species, and their function can be altered by metabolic and cardiovascular diseases. These alterations can influence H₂S signalling, further contributing to vascular dysfunction. PVAT-derived H₂S may have particular importance in obesity-related vascular disease, hypertension, and diabetes as it has direct paracrine effects on the vasculature. Understanding the role of PVAT-derived H₂S in both healthy and diseased states may provide new insights into preventing vascular dysfunction associated with PVAT changes. The dissection of the specific contributions of each enzyme involved in PVAT-derived H₂S biosynthesis could be relevant to fully understanding the complex role of H₂S in vascular health vs vascular disease. Further research into modulating PVAT-derived H₂S provides an exciting avenue to explore novel pharmacological targets against vascular disease pathogenesis.

Hydrogen sulfide (H₂S) is an endogenous gasotransmitter able to exert a pivotal role in different organs and systems, strongly influencing cardiovascular health. It is an endowed antioxidant, a vasorelaxant, and has cardioprotective properties, thanks to the activation of different classes of potassium channels and the interaction with several pathways including those involving sirtuins, nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor kappa B (NF-κB), and nitric oxide (NO) production. Alterations in the homeostasis of H₂S represent an etiopathogenetic factor in the onset and progression of cardiovascular diseases, such as hypertension, atherosclerosis, and vascular diabetic complications, highlighting the therapeutic potential of exogeneous H₂S-donors in H₂S-poor diseases. Several natural H₂S-donor compounds, or their precursors, derive from plants belonging to the Alliaceae (e.g., garlic and onion), Brassicaceae (e.g., broccoli and rocket salad), or Moringaceae (e.g., moringa) families. Preclinical studies demonstrated the antioxidant, vasoprotective, and anti-hypertensive properties of both plant extracts and isolated polysulfides or isothiocyanates (ITCs). In fact, polysulfides and ITCs are able to exert vascular effects superimposable to those induced by H₂S. Preclinical and clinical studies successfully demonstrated that garlic extracts decrease systolic and diastolic blood pressure and contrast endothelial dysfunction and atherosclerosis. Similarly, preclinical studies highlighted the anti-inflammatory, anti-hypertensive, and vasoprotective properties of ITCs. However, clinical studies only demonstrated the improvement of the lipid profile in healthy patients, with no effects on systolic or diastolic blood pressure. Taken together, these findings suggest that natural H₂S-donors could restore H₂S homeostasis, therefore preventing and/or contrasting cardiovascular diseases.

Type 2 diabetes (T2D) is a disease that occurs when cells do not respond normally to insulin, a condition called insulin resistance, which leads to high blood glucose levels. Although it can be treated pharmacologically, dietary habits beyond carbohydrate restriction can be highly relevant in the management of T2D. Emerging evidence supports the possibility that natural products (NPs) could contribute to managing blood glucose or counteract the undesirable effects of hyperglycemia and insulin resistance. This chapter summarizes the relevant preclinical evidence involving the flavonoid (-)-epicatechin (EC) in the optimization of glucose homeostasis, reducing insulin resistance and/or diabetes-associated disorders. Major effects of EC are observed on (i) intestinal functions, including digestive enzymes, glucose transporters, microbiota, and intestinal permeability, and (ii) redox homeostasis, including oxidative stress and inflammation. There is still a need for further clinical studies to confirm the in vitro and rodent data, allowing recommendations for EC, particularly in prediabetic and T2D patients. The collection of similar data and the lack of clinical evidence for EC is also applicable to other NPs.

Congenital disorders of glycosylation (CDG) constitute an increasing group of inborn metabolic disorders, with more than 170 described diseases to date. A disturbed glycosylation process characterizes them, with molecular defects localized in distinct cell compartments. In CDG, N-glycosylation, O-glycosylation, glycosylation of lipids (including phosphatidylinositol) as well as the glycosaminoglycan synthesis can be affected. Owing to the importance of glycosylation for the function of concerned proteins and lipids, glycosylation defects have diverse clinical consequences. CDG affected individuals often present with a non-specific multivisceral syndrome including neurological involvement, intellectual disability, dysmorphia, and hepatopathy. As CDG are rare diseases frequently lacking distinctive symptoms, biochemical and genetic testing bear important and complementary diagnostic roles.After an introduction on glycosylation and CDG, we review current biomarkers and analytical techniques in the field. Furthermore, we illustrate their interests in the follow-up of proven therapeutic approaches including D-mannose in MPI-CDG, D-galactose in PGM1-CDG, and manganese (MnSO₄) in TMEM165-CDG.

Glycosaminoglycans (GAG) are polysaccharides that are ubiquitous on the surface of all mammalian cells, interacting with a multitude of proteins and orchestrating essential physiological and pathological processes. Among various GAG structures, heparan sulfate (HS) stands out for its intricate structure, positioning it as a significant cell-surface molecule capable of regulating wide range of cellular functions. Consequently, investigating the structure-activity relationships (SARs) with well-defined HS ligands emerges as an attractive avenue advancing drug discovery and biosensors. This chapter outlines a modular divergent strategy for synthesizing HS oligosaccharides to elucidate SARs. Here, we provide a literature overview on the synthesis of disaccharide building blocks, employing different orthogonal protecting groups, promoters, and optimization conditions to improve their suitability for subsequent oligosaccharide synthesis. Further, we highlight the synthesis of universal disaccharide building blocks derived from natural polysaccharides. We also provide insights of one-pot method and automated solid-phase synthesis of HS oligosaccharides. Finally, we review the status of SARs of popular heparan sulfate binding proteins (HSBPs).

Quantitative Systems Pharmacology (QSP) models offer a promising approach to extrapolate drug efficacy across different patient populations, particularly in rare diseases. Unlike conventional empirical models, QSP models can provide a mechanistic understanding of disease progression and therapeutic response by incorporating current disease knowledge into the descriptions of biomarkers and clinical endpoints. This allows for a holistic representation of the disease and drug response. The mechanistic nature of QSP models is well suited to pediatric extrapolation concepts, providing a quantitative method to assess disease and drug response similarity between adults and pediatric patients. The application of a QSP-based assessment of the disease and drug similarity in adult and pediatric patients in the clinical development program of olipudase alfa, a treatment for Acid Sphingomyelinase Deficiency (ASMD), illustrates the potential of this approach.