The role of Ginkgo Folium on antitumor: Bioactive constituents and the potential mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: Ginkgo biloba L. is a well-known and highly regarded resource in Chinese traditional medicine due to its effectiveness and safety. Ginkgo Folium, the leaf of Ginkgo biloba L., contains biologically active constituents with diverse pharmacological activities. Recent studies have shown promising antitumor effects of the bioactive constituents found in Ginkgo Folium against various types of cancer cells, highlighting its potential as a natural source of antitumor agents. Further research is needed to elucidate the underlying mechanisms and optimize its therapeutic potential. AIM OF THE REVIEW: To provide a detailed understanding of the pharmacological activities of Ginkgo Folium and its potential therapeutic benefits for cancer patients. MATERIALS AND METHODS: In this study, we conducted a thorough and systematic search of multiple online databases, including PubMed, Web of Science, Medline, using relevant keywords such as "Ginkgo Folium," "flavonoids," "terpenoids," "Ginkgo Folium extracts," and "antitumor" to cover a broad range of studies that could inform our review. Additionally, we followed a rigorous selection process to ensure that the studies included in our review met the predetermined inclusion criteria. RESULTS: The active constituents of Ginkgo Folium primarily consist of flavonoids and terpenoids, with quercetin, kaempferol, isorhamnetin, ginkgolides, and bilobalide being the major compounds. These active constituents exert their antitumor effects through crucial biological events such as apoptosis, cell cycle arrest, autophagy, and inhibition of invasion and metastasis via modulating diverse signaling pathways. During the process of apoptosis, active constituents primarily exert their effects by modulating the caspase-8 mediated death receptor pathway and caspase-9 mediated mitochondrial pathway via regulating specific signaling pathways. Furthermore, by modulating multiple signaling pathways, active constituents effectively induce G1, G0/G1, G2, and G2/M phase arrest. Among these, the pathways associated with G2/M phase arrest are particularly extensive, with the cyclin-dependent kinases (CDKs) being most involved. Moreover, active constituents primarily mediate autophagy by modulating certain inflammatory factors and stressors, facilitating the fusion stage between autophagosomes and lysosomes. Additionally, through the modulation of specific chemokines and matrix metalloproteinases, active constituents effectively inhibit the processes of epithelial-mesenchymal transition (EMT) and angiogenesis, exerting a significant impact on cellular invasion and migration. Synergistic effects are observed among the active constituents, particularly quercetin and kaempferol. CONCLUSION: Active components derived from Ginkgo Folium demonstrate a comprehensive antitumor effect across various levels and pathways, presenting compelling evidence for their potential in new drug development. However, in order to facilitate their broad and adaptable clinical application, further extensive experimental investigations are required to thoroughly explore their efficacy, safety, and underlying mechanisms of action.

ß-Elemene induced ferroptosis via TFEB-mediated GPX4 degradation in EGFR wide-type non-small cell lung cancer.

INTRODUCTION: ß-Elemene (ß-ELE), derived from Curcuma wenyujin, has anticancer effect on non-small cell lung cancer (NSCLC). However, the potential target and detail mechanism were still not clear. TFEB is the master regulator of lysosome biogenesis. Ferroptosis, a promising strategy for cancer therapy could be triggered via suppression on glutathione peroxidase 4 (GPX4). Weather TFEB-mediated lysosome degradation contributes to GPX4 decline and how ß-ELE modulates on this process are not clear. OBJECTIVES: To observe the action of ß-ELE on TFEB, and the role of TFEB-mediated GPX4 degradation in ß-ELE induced ferroptosis. METHODS: Surface plasmon resonance (SPR) and molecular docking were applied to observe the binding affinity of ß-ELE on TFEB. Activation of TFEB and lysosome were observed by immunofluorescence, western blot, flow cytometry and qPCR. Ferroptosis induced by ß-ELE was observed via lipid ROS, a labile iron pool (LIP) assay and western blot. A549TFEB KO cells were established via CRISPR/Cas9. The regulation of TFEB on GPX4 and ferroptosis was observed in ß-ELE treated A549WT and A549TFEB KO cells, which was further studied in orthotopic NOD/SCID mouse model. RESULTS: ß-ELE can bind to TFEB, notably activate TFEB, lysosome and transcriptional increase on downstream gene GLA, MCOLN1, SLC26A11 involved in lysosome activity in EGFR wild-type NSCLC cells. ß-ELE increased GPX4 ubiquitination and lysosomal localization, with the increase on lysosome degradation of GPX4. Furthermore, ß-ELE induced ferroptosis, which could be promoted by TFEB overexpression or compromised by TFEB knockout. Genetic knockout or inactivation of TFEB compromised ß-ELE induced lysosome degradation of GPX4, which was further demonstrated in orthotopic NSCLC NOD/SCID mice model. CONCLUSION: This study firstly demonstrated that TFEB promoted GPX4 lysosome degradation contributes to ß-ELE induced ferroptosis in EGFR wild-type NSCLC, which gives a clue that TFEB mediated GPX4 degradation would be a novel strategy for ferroptosis induction and NSCLC therapy.

Matrix metalloproteinase-9 regulates afferent arteriolar remodeling and function in hypertension-induced kidney disease.

This study tested if matrix metalloproteinase (MMP)-9 promoted microvascular pathology that initiates hypertensive (HT) kidney disease in salt-sensitive (SS) Dahl rats. SS rats lacking Mmp9 (Mmp9-/-) and littermate control SS rats were studied after one week on a normotensive 0.3% sodium chloride (Pre-HT SS and Pre-HT Mmp9-/-) or a hypertension-inducing diet containing 4.0% sodium chloride (HT SS and HT Mmp9-/-). Telemetry-monitored blood pressure of both the HT SS and HT Mmp9-/- rats increased and did not differ. Kidney microvessel transforming growth factor-beta 1 (Tgfb1) mRNA did not differ between Pre-HT SS and Pre-HT Mmp9-/- rats, but with hypertension and expression of Mmp9 and Tgfb1 increased in HT SS rats, along with phospho-Smad2 labeling of nuclei of vascular smooth muscle cells, and with peri-arteriolar fibronectin deposition. Loss of MMP-9 prevented hypertension-induced phenotypic transformation of microvascular smooth muscle cells and the expected increased microvascular expression of pro-inflammatory molecules. Loss of MMP-9 in vascular smooth muscle cells in vitro prevented cyclic strain-induced production of active TGF-ß1 and phospho-Smad2/3 stimulation. Afferent arteriolar autoregulation was impaired in HT SS rats but not in HT Mmp9-/- rats or the HT SS rats treated with doxycycline, an MMP inhibitor. HT SS but not HT Mmp9-/- rats showed decreased glomerular Wilms Tumor 1 protein-positive cells (a marker of podocytes) along with increased urinary podocin and nephrin mRNA excretion, all indicative of glomerular damage. Thus, our findings support an active role for MMP-9 in a hypertension-induced kidney microvascular remodeling process that promotes glomerular epithelial cell injury in SS rats.

Restoration of afferent arteriolar autoregulatory behavior in ischemia-reperfusion injury in rat kidneys.

Renal autoregulation is critical in maintaining stable renal blood flow (RBF) and glomerular filtration rate (GFR). Renal ischemia-reperfusion (IR)-induced kidney injury is characterized by reduced RBF and GFR. The mechanisms contributing to renal microvascular dysfunction in IR have not been fully determined. We hypothesized that increased reactive oxygen species (ROS) contributed to impaired renal autoregulatory capability in IR rats. Afferent arteriolar autoregulatory behavior was assessed using the blood-perfused juxtamedullary nephron preparation. IR was induced by 60 min of bilateral renal artery occlusion followed by 24 h of reperfusion. Afferent arterioles from sham rats exhibited normal autoregulatory behavior. Stepwise increases in perfusion pressure caused pressure-dependent vasoconstriction to 65 ± 3% of baseline diameter (13.2 ± 0.4 µm) at 170 mmHg. In contrast, pressure-mediated vasoconstriction was markedly attenuated in IR rats. Baseline diameter averaged 11.7 ± 0.5 µm and remained between 90% and 101% of baseline over 65-170 mmHg, indicating impaired autoregulatory function. Acute antioxidant administration (tempol or apocynin) to IR kidneys for 20 min increased baseline diameter and improved autoregulatory capability, such that the pressure-diameter profiles were indistinguishable from those of sham kidneys. Furthermore, the addition of polyethylene glycol superoxide dismutase or polyethylene glycol-catalase to the perfusate blood also restored afferent arteriolar autoregulatory responsiveness in IR rats, indicating the involvement of superoxide and/or hydrogen peroxide. IR elevated mRNA expression of NADPH oxidase subunits and monocyte chemoattractant protein-1 in renal tissue homogenates, and this was prevented by tempol pretreatment. These results suggest that ROS accumulation, likely involving superoxide and/or hydrogen peroxide, impairs renal autoregulation in IR rats in a reversible fashion.NEW & NOTEWORTHY Renal ischemia-reperfusion (IR) leads to renal microvascular dysfunction manifested by impaired afferent arteriolar autoregulatory efficiency. Acute administration of scavengers of reactive oxygen species, polyethylene glycol-superoxide dismutase, or polyethylene glycol-catalase following renal IR restored afferent arteriolar autoregulatory capability in IR rats, indicating that renal IR led to reversible impairment of afferent arteriolar autoregulatory capability. Intervention with antioxidant treatment following IR may improve outcomes in patients by preserving renovascular autoregulatory function and potentially preventing the progression to chronic kidney disease after acute kidney injury.

Avian erythroblastosis virus E26 oncogene homolog-1 (ETS-1) plays a role in renal microvascular pathophysiology in the Dahl salt-sensitive rat.

Prior studies reported that haploinsufficiency of the transcription factor ETS-1 is renoprotective in Dahl salt-sensitive rats, but the mechanism is unclear. Here, we tested whether ETS-1 is involved in hypertension-induced renal microvascular pathology and autoregulatory impairment. Hypertension was induced in salt-sensitive rats and salt-sensitive rats that are heterozygous with 1 wild-type or reference allele of Ets1 (SSEts1+/-) by feeding a diet containing 4% sodium chloride for 1 week. Increases in blood pressure did not differ. However, phosphorylated ETS-1 increased in afferent arterioles of hypertensive salt-sensitive rats, but not in hypertensive SSEts1+/- rats. Afferent arterioles of hypertensive salt-sensitive rats showed increased monocyte chemotactic protein-1 expression and infiltration of CD68 positive monocytes/macrophages. Isolated kidney microvessels showed increased mRNA expression of vascular cell adhesion molecule, intercellular adhesion molecule, P-selectin, fibronectin, transforming growth factor-ß, and collagen I in hypertensive salt-sensitive rats compared with hypertensive SSEts1+/- rats. Using the in vitro blood-perfused juxtamedullary nephron preparation, pressure-mediated afferent arteriolar responses were significantly blunted in hypertensive salt-sensitive rats compared to hypertensive SSEts1+/- rats. Over a 65-170 mm Hg pressure range tested baseline arteriolar diameters averaged 15.1 µm and remained between 107% and 89% of baseline diameter in hypertensive salt-sensitive rats vs. 114% and 73% in hypertensive SSEts1+/- rats (significantly different). Thus, ETS-1 participates in renal arteriolar pathology and autoregulation and thereby is involved in hypertension-mediated kidney injury in salt-sensitive rats.

Rho kinase inhibitors reduce voltage-dependent Ca2+ channel signaling in aortic and renal microvascular smooth muscle cells.

Voltage-dependent L-type Ca2+ channels (L-VDCCs) and the RhoA/Rho kinase pathway are two predominant intracellular signaling pathways that regulate renal microvascular reactivity. Traditionally, these two pathways have been thought to act independently; however, recent evidence suggests that these pathways could be convergent. We hypothesized that Rho kinase inhibitors can influence L-VDCC signaling. The effects of Rho kinase inhibitors Y-27632 or RKI-1447 on KCl-induced depolarization or the L-VDCC agonist Bay K8644 were assessed in afferent arterioles using an in vitro blood-perfused rat juxtamedullary nephron preparation. Superfusion of KCl (30-90 mM) led to concentration-dependent vasoconstriction of afferent arterioles. Administration of Y-27632 (1, 5, and 10 µM) or RKI-1447 (0.1, 1, and 10 µM) significantly increased the starting diameter by 16-65%. KCl-induced vasoconstriction was markedly attenuated with 5 and 10 µM Y-27632 and with 10 µM RKI-1447 (P < 0.05 vs. KCl alone). Y-27632 (5 µM) also significantly attenuated Bay K8644-induced vasoconstriction (P < 0.05). Changes in intracellular Ca2+ concentration ([Ca2+]i) were estimated by fura-2 fluorescence during KCl-induced depolarization in cultured A7r5 cells and in freshly isolated preglomerular microvascular smooth muscle cells. Administration of 90 mM KCl significantly increased fura-2 fluorescence in both cell types. KCl-mediated elevation of [Ca2+]i in A7r5 cells was suppressed by 1-10 µM Y-27632 (P < 0.05), but 10 µM Y-27632 was required to suppress Ca2+ responses in preglomerular microvascular smooth muscle cells. RKI-1447, however, significantly attenuated KCl-mediated elevation of [Ca2+]i. Y-27632 markedly inhibited Bay K8644-induced elevation of [Ca2+]i in both cell types. The results of the present study indicate that the Rho kinase inhibitors Y-27632 and RKI-1447 can partially inhibit L-VDCC function and participate in L-VDCC signaling.

Pentosan polysulfate preserves renal microvascular P2X1 receptor reactivity and autoregulatory behavior in DOCA-salt hypertensive rats.

Inflammation contributes to ANG II-associated impairment of renal autoregulation and microvascular P2X1 receptor signaling, but its role in renal autoregulation in mineralocorticoid-induced hypertension is unknown. Autoregulatory behavior was assessed using the blood-perfused juxtamedullary nephron preparation. Hypertension was induced in uninephrectomized control rats (UNx) by subcutaneous implantation of a DOCA pellet plus administration of 1% NaCl in the drinking water (DOCA-salt) for 3 wk. DOCA-salt rats developed hypertension that was unaltered by anti-inflammatory treatment with pentosan polysulfate (DOCA-salt+PPS) but was suppressed with "triple therapy" (hydrochlorothiazide, hydralazine, and reserpine; DOCA-salt+TTx). Baseline arteriolar diameters were similar across all groups. UNx rats exhibited pressure-dependent vasoconstriction with diameters declining to 69 ± 2% of control at 170 mmHg, indicating intact autoregulation. DOCA-salt treatment significantly blunted this pressure-mediated vasoconstriction. Diameters remained between 91 ± 4 and 98 ± 3% of control over 65-170 mmHg, indicating impaired autoregulation. In contrast, pressure-mediated vasoconstriction was preserved in DOCA-salt+PPS and DOCA-salt+TTx rats, reaching 77 ± 7 and 75 ± 3% of control at 170 mmHg, respectively. ATP is required for autoregulation via P2X1 receptor activation. ATP- and ß,γ-methylene ATP (P2X1 receptor agonist)-mediated vasoconstriction were markedly attenuated in DOCA-salt rats compared with UNx (P < 0.05), but significantly improved by PPS or TTx (P < 0.05 vs. DOCA-salt) treatment. Arteriolar responses to adenosine and UTP (P2Y2 receptor agonist) were unaffected by DOCA-salt treatment. PPS and TTx significantly reduced MCP-1 and protein excretion in DOCA-salt rats. These results support the hypothesis that hypertension triggers inflammatory cascades but anti-inflammatory treatment preserves renal autoregulation in DOCA-salt rats, most likely by normalizing renal microvascular reactivity to P2X1 receptor activation.

Metabolism of (13)C5-hydroxyproline in mouse models of Primary Hyperoxaluria and its inhibition by RNAi therapeutics targeting liver glycolate oxidase and hydroxyproline dehydrogenase.

Excessive endogenous oxalate synthesis can result in calcium oxalate kidney stone formation and renal failure. Hydroxyproline catabolism in the liver and kidney contributes to endogenous oxalate production in mammals. To quantify this contribution we have infused Wt mice, Agxt KO mice deficient in liver alanine:glyoxylate aminotransferase, and Grhpr KO mice deficient in glyoxylate reductase, with (13)C5-hydroxyproline. The contribution of hydroxyproline metabolism to urinary oxalate excretion in Wt mice was 22±2%, 42±8% in Agxt KO mice, and 36%±9% in Grhpr KO mice. To determine if blocking steps in hydroxyproline and glycolate metabolism would decrease urinary oxalate excretion, mice were injected with siRNA targeting the liver enzymes glycolate oxidase and hydroxyproline dehydrogenase. These siRNAs decreased the expression of both enzymes and reduced urinary oxalate excretion in Agxt KO mice, when compared to mice infused with a luciferase control preparation. These results suggest that siRNA approaches could be useful for decreasing the oxalate burden on the kidney in individuals with Primary Hyperoxaluria.

Endothelin contributes to blunted renal autoregulation observed with a high-salt diet.

Autoregulation of renal blood flow (RBF) is an essential function of the renal microcirculation that has been previously shown to be blunted by excessive dietary salt. Endogenous endothelin 1 (ET-1) is increased following a high-salt (HS) diet and contributes to the control of RBF but the differential effects of ET-1 on renal microvessel autoregulation in response to HS remain to be established. We hypothesized that a HS diet increases endothelin receptor activation in normal Sprague-Dawley rats and blunts autoregulation of RBF. The role of ET-1 in the blunted autoregulation produced by a HS diet was assessed in vitro and in vivo using the blood-perfused juxtamedullary nephron preparation and anesthetized rats, respectively. Using highly selective antagonists, we observed that blockade of either ETA or ETB receptors was sufficient to restore normal autoregulatory behavior in afferent arterioles from HS-fed rats. Additionally, normal autoregulatory behavior was restored in vivo in HS-fed rats by simultaneous ETA and ETB receptor blockade, whereas blockade of ETB receptors alone showed significant improvement of normal autoregulation of RBF. Consistent with this observation, autoregulation of RBF in ETB receptor-deficient rats fed HS was similar to both ETB-deficient rats and transgenic control rats on normal-salt diets. These data support the hypothesis that endogenous ET-1, working through ETB and possibly ETA receptors, contributes to the blunted renal autoregulatory behavior in rats fed a HS diet.

Endothelin and the renal microcirculation.

Endothelin (ET) is one of the most potent renal vasoconstrictors. Endothelin plays an essential role in the regulation of renal blood flow, glomerular filtration, sodium and water transport, and acid-base balance. ET-1, ET-2, and ET-3 are the three distinct endothelin isoforms comprising the endothelin family. ET-1 is the major physiologically relevant peptide and exerts its biological activity through two G-protein-coupled receptors: ET(A) and ET(B). Both ET(A) and ET(B) are expressed by the renal vasculature. Although ET(A) are expressed mainly by vascular smooth muscle cells, ET(B) are expressed by both renal endothelial and vascular smooth muscle cells. Activation of the endothelin system, or overexpression of downstream endothelin signaling pathways, has been implicated in several pathophysiological conditions including hypertension, acute kidney injury, diabetic nephropathy, and immune nephritis. In this review, we focus on the effects of endothelin on the renal microvasculature, and update recent findings on endothelin in the regulation of renal hemodynamics.

Sphingosine-1-phosphate evokes unique segment-specific vasoconstriction of the renal microvasculature.

Sphingosine-1-phosphate (S1P), a bioactive sphingolipid metabolite, has been implicated in regulating vascular tone and participating in chronic and acute kidney injury. However, little is known about the role of S1P in the renal microcirculation. Here, we directly assessed the vasoresponsiveness of preglomerular and postglomerular microvascular segments to exogenous S1P using the in vitro blood-perfused juxtamedullary nephron preparation. Superfusion of S1P (0.001-10 µM) evoked concentration-dependent vasoconstriction in preglomerular microvessels, predominantly afferent arterioles. After administration of 10 µM S1P, the diameter of afferent arterioles decreased to 35%±5% of the control diameter, whereas the diameters of interlobular and arcuate arteries declined to 50%±12% and 68%±6% of the control diameter, respectively. Notably, efferent arterioles did not respond to S1P. The S1P receptor agonists FTY720 and FTY720-phosphate and the specific S1P1 receptor agonist SEW2871 each evoked modest afferent arteriolar vasoconstriction. Conversely, S1P2 receptor inhibition with JTE-013 significantly attenuated S1P-mediated afferent arteriolar vasoconstriction. Moreover, blockade of L-type voltage-dependent calcium channels with diltiazem or nifedipine attenuated S1P-mediated vasoconstriction. Intravenous injection of S1P in anesthetized rats reduced renal blood flow dose dependently. Western blotting and immunofluorescence revealed S1P1 and S1P2 receptor expression in isolated preglomerular microvessels and microvascular smooth muscle cells. These data demonstrate that S1P evokes segmentally distinct preglomerular vasoconstriction via activation of S1P1 and/or S1P2 receptors, partially via L-type voltage-dependent calcium channels. Accordingly, S1P may have a novel function in regulating afferent arteriolar resistance under physiologic conditions.

P2 receptors in renal autoregulation.

Autoregulation of renal blood flow and glomerular filtration rate is an essential function of the renal microcirculation. While the existence of this phenomenon has been known for many years, the exact mechanisms that underlie this regulatory system remain poorly understood. The work of many investigators has provided insights into many aspects of the autoregulatory mechanism, but many critical components remain elusive. This review is intended to update the reader on the role of P2 purinoceptors as a postulated mechanism responsible for renal autoregulatory resistance adjustments. It will summarize recent advances in normal function and it will touch on more recent ideas regarding autoregulatory insufficiency in hypertension and inflammation. Current thoughts on the nature of the mechanosensor responsible for myogenic behavior will be also be discussed as well as current thoughts on the mechanisms involved in ATP release to the extracellular fluid space.

Immunosuppression preserves renal autoregulatory function and microvascular P2X(1) receptor reactivity in ANG II-hypertensive rats.

Autoregulation is critical for protecting the kidney against arterial pressure elevation and is compromised in some forms of hypertension. Evidence indicates that activated lymphocytes contribute importantly to cardiovascular injury in hypertension. We hypothesized that activated lymphocytes contribute to renal vascular dysfunction by impairing autoregulation and P2X(1) receptor signaling in ANG II-infused hypertensive rats. Male Sprague-Dawley rats receiving ANG II infusion were treated with a lymphocyte proliferation inhibitor, mycophenolate mofetil (MMF) for 2 wk. Autoregulation was assessed in vitro and in vivo using the blood-perfused juxtamedullary nephron preparation and anesthetized rats, respectively. ANG II-treated rats exhibited impaired autoregulation. At the single vessel level, pressure-mediated afferent arteriolar vasoconstriction was significantly blunted (P < 0.05 vs. control rats). At the whole kidney level, renal blood flow passively decreased as renal perfusion pressure was reduced. MMF treatment did not alter the ANG II-induced hypertensive state; however, MMF did preserve autoregulation. The autoregulatory profiles in both in vitro or in vivo settings were similar to the responses from control rats despite persistent hypertension. Autoregulatory responses are linked to P2X(1) receptor activation. Accordingly, afferent arteriolar responses to ATP and the P2X(1) receptor agonist ß,γ-methylene ATP were assessed. ATP- or ß,γ-methylene ATP-induced vasoconstriction was significantly attenuated in ANG II-infused hypertensive rats but was normalized by MMF treatment. Moreover, MMF prevented elevation of plasma transforming growth factor-ß1 concentration and lymphocyte and macrophage infiltration in ANG II-infused kidneys. These results suggest that anti-inflammatory treatment with MMF prevents lymphocyte infiltration and preserves autoregulation in ANG II-infused hypertensive rats, likely by normalizing P2X(1) receptor activation.

Endothelin and the renal vasculature.

The endothelin (ET) system comprises a family of three isopeptides (ET-1, ET-2, and ET-3)involved in diverse physiological and pathophysiological events. ET-1 is the major renal peptide that exerts its biological activity by binding to ET(A) and ET(B) receptors. Both ET(A) and ET(B) receptors are expressed by renal microvascular smooth muscle cells, where activation causes vasoconstriction. ET(B) receptors are also expressed by microvascular endothelial cells, where activation leads to vasodilator responses. ET-1 influences preglomerular and postglomerular microvascular tone and thus can significantly influence renal hemodynamics. Alteration of renal ET-1 synthesis and receptor expression has been reported in cardiovascular diseases, and could contribute to renal injury by altering renal microvascular reactivity. In this brief review, we will try to summarize what is known about ET control of renal microvascular function.

Amphiphilic hollow carbonaceous microspheres for the sorption of phenol from water.

Amphiphilic porous hollow carbonaceous spheres (PHCSs) were synthesized via mild hydrothermal treatment of yeast cells and further pyrolyzing post treatment. The morphology, chemical composition, porosity, and structure of the carbonaceous materials were investigated. It is evident that the carbonaceous materials were composed of the carbonized organic matter (COM) and the noncarbonized organic matter (NOM), and the relative COM and NOM fractions could be adjusted through changing the temperature of hydrothermal and/or pyrolyzing treatment. The phenol sorption properties of the carbonaceous materials had been investigated and the sorption isotherms fit well to the modified Freundlich equation. It was found that the sorption isotherm of phenol onto PHCSs was practically linear even at extreme high concentrations, which was fewer reported for activated carbon or other inorganic materials. This type of sorption isothermals was assigned to a partition mechanism, and the largest value of the partition coefficient (K(f)) and carbon-normalized K(f) (K(oc)) is 56.7 and 91.5 mL g(-1), respectively. Moreover, PHCSs exhibit fast sorption kinetic and facile regeneration property. The results indicate PHCSs are potential effective sorbents for removal of undesirable organic chemicals in wastewater, especially at high concentrations.

Role of adenosine 5'-triphosphate in regulating renal microvascular function and in hypertension.

ATP is an essential energy substrate for cellular metabolism, but it can also influence many biological processes when released into the extracellular milieu. Research has established that extracellular ATP acts as an autocrine/paracrine factor that regulates many physiological functions. Alternatively, excessive extracellular ATP levels contribute to pathophysiological processes, such as inflammation, cell proliferation and apoptosis, and atherosclerosis. Renal P2 receptors are widely distributed throughout glomeruli, vasculature, and tubular segments and participate in controlling renal vascular resistance, mediating renal autoregulation, and regulating tubular transport function. This review will focus on the role of ATP-P2 receptor signaling in regulating renal microvascular function and autoregulation, recent advances on the role of ATP-P2 signaling in hypertension-associated renal vascular injury, and emerging new directions.

P2X1 receptor-mediated vasoconstriction of afferent arterioles in angiotensin II-infused hypertensive rats fed a high-salt diet.

Experiments tested the hypothesis that P2 receptor reactivity is impaired in angiotensin (Ang) II hypertensive rats fed an 8%NaCl diet (Ang II+HS). Juxtamedullary afferent arteriolar autoregulatory behavior was determined over a pressure range of 65 to 200 mm Hg. Arteriolar responsiveness to P2X1 (ß,γ-methylene ATP) or P2Y2 receptor (uridine triphosphate) activation was determined in vitro. Systolic blood pressure averaged 126±3 and 225±4 mm Hg in control and Ang II+HS rats, respectively (P<0.05). In control kidneys, ß,γ-methylene ATP (10(-8) to 10(-4) mol/L) reduced arteriolar diameter by 8±3%, 13±5%, 19±5%, 22±6%, and 24±9%, respectively, whereas uridine triphosphate reduced diameter by 2±1%, 2±2%, 9±3%, 37±7%, and 58±7%. Autoregulation was markedly blunted in Ang II+HS kidneys, with arteriolar diameter remaining essentially unchanged when perfusion pressure increased to 200 mm Hg compared with a 40±2% decline in diameter observed in normal kidneys over the same pressure range (P<0.05). P2X1 receptor-mediated vasoconstriction was significantly attenuated in Ang II+HS kidneys. ß,γ-Methylene ATP reduced arteriolar diameter by 1±1%, 3±2%, 6±1%, 9±3%, and 7±1%, respectively (P<0.05), versus control rats. Similar patterns were noted when hypertensive perfusion pressures were used. Uridine triphosphate-mediated responses were unchanged in Ang II+HS rats compared with control, indicating preservation of P2Y2 receptor function. Ang II+HS blunted P2X1-mediated increases in intracellular Ca2+ concentration in preglomerular smooth muscle cells. Therefore, Ang II+HS rats exhibit attenuated afferent arteriolar responses to P2X1 receptor stimulation. These data support the hypothesis that P2X1 receptors are important for pressure-mediated autoregulatory responses. Impairment of P2X1 receptor function may explain the hypertension-induced decline in renal autoregulatory capability.