Antioxidant and anti–glycation activities correlates with phenolic composition of tropical medicinal herbs

ObjectiveTo determine the contribution of total phenolic content (TPC) in glycation inhibitory activity of common tropical medicinal food and spices with potential antioxidative properties.MethodsIn vitro glucose-bovine serum albumin (BSA) assay was used. Ethanolic extracts of ten common household condiments/herbs (Allium sativum, Zingiber officinale, Thymus vulgaris, Petroselinum crispum, Murraya koenigii Spreng, Mentha piperita L., Curcuma longa L., Allium cepa L., Allium fistulosum and Coriandrum sativum L.) were evaluated for antioxidative activity by 2,2-diphenyl-2-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) and the TPC, flavonoid and tannins content were determined.ResultsFindings showed good correlation between TPC/DPPH (r = 0.8), TPC/FRAP (r = 0.8), TPC/anti–glycation (r = 0.9), DPPH/anti–glycation (r = 0.6), FRAP/anti–glycation (r = 0.9), Flavonoid/anti–glycation (r = 0.7) and Tannins/anti–glycation (r = 0.8) and relatively fair correlation for TPC/Flavonoids (r = 0.5) and TPC/Tannins (r = 0.5). Results imply that these plants are potential sources of natural antioxidants which have free radical scavenging activity and might be used for reducing oxidative stress.ConclusionsThe positive glycation inhibitory and antioxidative activities of these tropical herbs suggest a possible role in targeting ageing, diabetic complications and oxidative stress related diseases.     

A comparative in vitro antioxidant potential profile of extracts from different parts of Fagonia cretica

ObjectiveTo evaluate antioxidant and radical scavenging activities of organic extracts from fruit, roots and aerial parts of Fagonia cretica.MethodsShed dried and powdered plant parts were initially extracted in methanol and subsequently partitioned in n-hexane, chloroform, ethyl acetate and 1-butanol successively. Antioxidant and radical scavenging potential of the methanol extracts and the fractions of each part were evaluated using total phenolic contents (TPC) and total flavonoid contents (TFC), 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation radicals scavenging, reducing power (potassium ferricyanide-trichloroacetic acid system), ferric ion reducing antioxidant potential, lipid peroxidation inhibition activity (linoleic acid system) and total antioxidant activity (phosphomolybdate) assays.ResultsTPC and TFC values for methanol extracts and various fractions ranged from 0.23-4.30 mg/L gallic acid equivalents and from 30-545 mg/L rutin equivalents, respectively. Overall, methanol extracts and all the fractions of root and aerial parts showed higher TPC and TFC values. Methanol extracts and aqueous fractions of root and aerial parts and the n-butanol fraction of root showed lower EC₅₀ values for 2,2-diphenyl-1-picrylhydrazyl scavenging than the other plant extracts. The 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging, total antioxidant potential and ferric ion reducing antioxidant potential values confirmed the presence of potent antioxidant principles in the methanol extract of roots. In general, all the extracts/fractions and especially those of root showed high antioxidant and radical scavenging activities.ConclusionsThe crude methanol extract of root can be explored further for in vivo studies. This study revealed the potent antioxidant potential of Fagonia cretica and its prospective efficacy against various reactive oxygen species-mediated diseases.     

VEGF-induced neoangiogenesis is mediated by NAADP and two-pore channel-2–dependent Ca2+ signaling

Vascular endothelial growth factor (VEGF) and its receptors VEGFR1/VEGFR2 play major roles in controlling angiogenesis, including vascularization of solid tumors. Here we describe a specific Ca²⁺ signaling pathway linked to the VEGFR2 receptor subtype, controlling the critical angiogenic responses of endothelial cells (ECs) to VEGF. Key steps of this pathway are the involvement of the potent Ca²⁺ mobilizing messenger, nicotinic acid adenine-dinucleotide phosphate (NAADP), and the specific engagement of the two-pore channel TPC2 subtype on acidic intracellular Ca²⁺ stores, resulting in Ca²⁺ release and angiogenic responses. Targeting this intracellular pathway pharmacologically using the NAADP antagonist Ned-19 or genetically using Tpcn2^−/− mice was found to inhibit angiogenic responses to VEGF in vitro and in vivo. In human umbilical vein endothelial cells (HUVECs) Ned-19 abolished VEGF-induced Ca²⁺ release, impairing phosphorylation of ERK1/2, Akt, eNOS, JNK, cell proliferation, cell migration, and capillary-like tube formation. Interestingly, Tpcn2 shRNA treatment abolished VEGF-induced Ca²⁺ release and capillary-like tube formation. Importantly, in vivo VEGF-induced vessel formation in matrigel plugs in mice was abolished by Ned-19 and, most notably, failed to occur in Tpcn2^−/− mice, but was unaffected in Tpcn1^−/− animals. These results demonstrate that a VEGFR2/NAADP/TPC2/Ca²⁺ signaling pathway is critical for VEGF-induced angiogenesis in vitro and in vivo. Given that VEGF can elicit both pro- and antiangiogenic responses depending upon the balance of signal transduction pathways activated, targeting specific VEGFR2 downstream signaling pathways could modify this balance, potentially leading to more finely tailored therapeutic strategies.In the adult the formation of new capillaries is an uncommon occurrence mostly restricted to pathological rather than physiological conditions, the majority of blood vessels remaining quiescent once organ growth is accomplished (1). Physiological neoangiogenesis is generally restricted to body sites undergoing regeneration or restructuring (e.g., tissue lesion repair and corpus luteum formation), whereas pathological neoangiogenesis takes place in different diseases ranging from macular degeneration to atherosclerosis, and is vital for the highly noxious development of solid tumors, thus representing a promising target for therapeutic strategies (2). Vascular endothelial growth factors (VEGF), and in particular the family member VEGF-A, are major regulators of angiogenesis and regulate ECs, mainly through the stimulation of VEGF receptor-2 (VEGFR2), a receptor tyrosine kinase, to induce cell proliferation, migration, and sprouting in the early stages of angiogenesis (3, 4). Antiangiogenic agents that target VEGF signaling have become an important component of therapies in multiple cancers, but their use is limited by acquisition of resistance to their therapeutic effects (5, 6). When overall VEGF receptor (VEGFR) signaling is experimentally impaired by the use of blocking antibodies or of specific tyrosine kinase inhibitors, alternative cellular and tissue strategies nullify the success of such interventions (5, 7, 8). Resistance to anti-VEGF therapies may occur through a variety of mechanisms, including evocation of alternative compensatory factors, selection of hypoxia-resistant tumor cells, action of proangiogenic circulating cells, and increased circulating nontumor proangiogenic factors. Moreover, cross-interactions (both cellular and humoral) between ECs and other environmental cues have to be taken into account for the ultimate aim of tailoring therapeutic interventions according to the specific pattern of the angiogenic microenvironment and EC conditions (5–7). The search for novel key downstream effectors is therefore of potential significance in the perspective of angiogenesis control in cancer progression.Autophosphorylation of VEGFR2 upon binding VEGF results in the activation of downstream signaling cascades through complex and manifold molecular interactions that transmit signals leading to angiogenic responses. Stimulation of different EC types via VEGFR2 results in increases in intracellular free calcium concentrations [Ca²⁺]_i (9, 10) and the crucial role of this signaling element in the regulation of EC functions and angiogenesis is recognized (11, 12), and thought to be largely mediated by the phospholipase Cγ (PLCγ)/inositol 1,4,5 trisphosphate (IP₃) signaling pathway (10). It has been reported that IP₃ releases Ca²⁺ from intracellular stores in ECs, increasing [Ca²⁺]_i, and is augmented by store-operated Ca²⁺ influx (13). This signaling primes the endothelium for angiogenesis through the activation of downstream effectors such as endothelial nitric oxide synthase (eNOS), protein kinases C (PKC), and mitogen-activated protein kinases (MAPKs). Indeed, it has been reported that the interplay between IP₃-dependent Ca²⁺ mobilization and store-operated Ca²⁺ entry produces Ca²⁺ signals whose inhibition impairs the angiogenic effect of VEGF (14, 15). Given the complexity of both VEGF and Ca²⁺ signaling, and the crucial finding that VEGF evokes pro- and antiangiogenic responses, it is clear that the specificity of VEGF-evoked Ca²⁺ signatures deserves further investigation.Differences in Ca²⁺ signatures, which are key to determining specific Ca²⁺-dependent cellular responses, rely upon often complex spatiotemporal variations in [Ca²⁺]_i (16). A major determinant of these are based on functionally distinct intracellular Ca²⁺-mobilizing messengers, namely IP₃ and cyclic adenosine diphosphoribose (cADPR), which mobilize Ca²⁺ from the endoplasmic reticulum (ER) stores, and nicotinic acid adenine dinucleotide phosphate (NAADP), which triggers Ca²⁺ release from acidic organelles, such as lysosomes and endosomes (17, 18). NAADP likely targets a channel distinct from IP₃ and ryanodine receptors (RyRs), known as two-pore channels (TPCs) (19–25), and the resulting localized NAADP-evoked Ca²⁺ signals may in some cases be globalized via IP₃ and RyRs through Ca²⁺-induced Ca²⁺ release (26, 27). However, in a few cell types, direct activation of RyRs and Ca²⁺ influx channels by NAADP have also been proposed as alternative mechanisms (28, 29). It has been demonstrated that NAADP-sensitive Ca²⁺ stores are present in the endothelium, and that NAADP is capable of regulating vascular smooth muscle contractility and blood pressure by EC-dependent mechanisms (30). In addition, we have previously demonstrated that NAADP is a specific and essential intracellular mediator of ECs histamine H₁ receptors, evoking [Ca²⁺]_i release and secretion of von Willebrand factor, which requires the functional expression of TPCs (31).In the present work, we identify a novel pathway for VEGFR2 signal transduction whereby receptor activation leads to NAADP and TPC2-dependent Ca²⁺ release from acidic Ca²⁺ stores, which in turn controls angiogenic response in vitro and in vivo. These findings demonstrate, to our knowledge for the first time, the direct relationship between NAADP-mediated Ca²⁺ release and the signaling mechanisms underlying ECs angiogenesis mediated by VEGF.     

改性间位芳香族聚酰胺的合成及热性能研究

采用低温溶液法共缩聚反应合成了对苯二甲酰氯(TPC)摩尔分数为0.05～0.15的改性间位芳香族聚酰胺(PMIA)共聚物.用1H-NMR对改性共聚物进行分析,讨论了TPC的含量对共聚物比浓对数粘度的影响,对改性聚合物进行了热失重分析,并用红外光谱跟踪法探讨了共聚物的热降解过程,并和纯的PMIA进行比较.实验结果表明:用TPC改性PMIA具有更好的耐热性,而且随着TPC含量的增加,耐热性更好.     

Photodynamic therapy targeting neuropilin-1: Interest of pseudopeptides with improved stability properties

The general strategy developed aims to favor the vascular effect of photodynamic therapy by targeting tumor vasculature. Since angiogenic endothelial cells represent an interesting target to potentiate this vascular effect, we previously described the conjugation of a photosensitizer to a peptide targeting neuropilins (NRPs) over-expressed specially in tumor angiogenic vessels and we recently characterized the mechanism of photosensitization-induced thrombogenic events. Nevertheless, in glioma-bearing nude mice, we demonstrated that the peptide moiety was degraded to various rates according to time after intravenous administration. In this study, new peptidases-resistant pseudopeptides were tested, demonstrating a molecular affinity for NRP-1 and NRP-2 recombinant chimeric proteins and devoid of affinity for VEGF receptor type 1 (Flt-1). To argue the involvement of NRP-1, MDA-MB-231 breast cancer cells were used, strongly over-expressing NRP-1 receptor. We evidenced a statistically significant decrease of the different peptides-conjugated photosensitizers uptake after RNA interference-mediated silencing of NRP-1. Peptides-conjugated photosensitizers allowed a selective accumulation into cells. In mice, no degradation was observed in plasma in vivo 4 h after intravenous injection by MALDI-TOF mass spectrometry. This study draws attention to this potential problem with peptides, especially in the case of targeting strategies, and provides useful information for the future design of more stable molecules.     

Quinoline alkaloids in honey: Further analytical (HPLC-DAD-ESI-MS,multidimensional diffusion-ordered NMR spectroscopy), theoretical and chemometric studies

The wound-healing properties of honey are well established and it has been suggested that, among its pharmaco-active constituents, kynurenic acid (KA) exerts antinociceptive action on injured tissue by antagonizing NMDA at peripheral GABA receptors. The aim of this study was to investigate the quantitative profile of KA and of two recently identified, structurally related derivatives, 3-pyrrolidinyl-kynurenic acid (3-PKA) and its γ-lactamic derivative (γ-LACT-3-PKA), by examining their mass spectrometric behavior, in honeys from different botanical sources. We used a combination of HPLC-DAD-ESI-MS and NMR techniques (one-dimensional ¹H NMR and diffusion-ordered spectroscopy NMR).     

Total phallic construction techniques in transgender men: an updated narrative review

From 2012, the World Professional Association Transgender Health defined a structured therapeutic path and standards of care for transgender patients undergoing genital gender affirming surgery (GGAS). The main goal of GGAS in transgender males is to provide patients with an aesthetically appealing appearance of the neophallus that should allow standing micturition and enabling penetrative intercourse along with erogenous and tactile sensitivity. The optimal procedure should be safe, reproducible and performed in the fewest number of surgical stages. The ideal technique for total phallic construction (TPC) has not yet been demonstrated; TPC remains challenging and, from a functional point of view, it is also make more demanding as yet there are no perfect replacement materials for erectile and urethral tissues. Several procedures and different type of flaps (pedicled and free-flaps) have been proposed and investigated over time to address TPC with significant advances over the years especially after microsurgical procedures introduction. Due to its high complexity TPC is not free from complications. Local tissue ischaemic complications, complete and partial flap loss, donor site morbidity and urethral complications (fistulae and strictures) are reported. This narrative review aims to provide the readers with a contemporary overview of surgical procedures for TPC in transgender males focusing on key surgical steps, as well as surgical and functional outcomes.