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Experimental Physiology May 2024It has been proposed that diuretics can improve renal tissue oxygenation through inhibition of tubular sodium reabsorption and reduced metabolic demand. However, the...
It has been proposed that diuretics can improve renal tissue oxygenation through inhibition of tubular sodium reabsorption and reduced metabolic demand. However, the impact of clinically used diuretic drugs on the renal cortical and medullary microcirculation is unclear. Therefore, we examined the effects of three commonly used diuretics, at clinically relevant doses, on renal cortical and medullary perfusion and oxygenation in non-anaesthetised healthy sheep. Merino ewes received acetazolamide (250 mg; n = 9), furosemide (20 mg; n = 10) or amiloride (10 mg; n = 7) intravenously. Systemic and renal haemodynamics, renal cortical and medullary tissue perfusion and , and renal function were then monitored for up to 8 h post-treatment. The peak diuretic response occurred 2 h (99.4 ± 14.8 mL/h) after acetazolamide, at which stage cortical and medullary tissue perfusion and were not significantly different from their baseline levels. The peak diuretic response to furosemide occurred at 1 h (196.5 ± 12.3 mL/h) post-treatment but there were no significant changes in cortical and medullary tissue oxygenation during this period. However, cortical tissue fell from 40.1 ± 3.8 mmHg at baseline to 17.2 ± 4.4 mmHg at 3 h and to 20.5 ± 5.3 mmHg at 6 h after furosemide administration. Amiloride did not produce a diuretic response and was not associated with significant changes in cortical or medullary tissue oxygenation. In conclusion, clinically relevant doses of diuretic agents did not improve regional renal tissue oxygenation in healthy animals during the 8 h experimentation period. On the contrary, rebound renal cortical hypoxia may develop after dissipation of furosemide-induced diuresis.
Topics: Animals; Furosemide; Acetazolamide; Amiloride; Diuretics; Sheep; Female; Kidney Cortex; Kidney Medulla; Oxygen; Hemodynamics; Oxygen Consumption
PubMed: 38551893
DOI: 10.1113/EP091479 -
Therapeutic Advances in Chronic Disease 2024The effectiveness and side effects between different medical treatments in patients with primary hyperaldosteronism have not been systematically studied.
BACKGROUND
The effectiveness and side effects between different medical treatments in patients with primary hyperaldosteronism have not been systematically studied.
OBJECTIVE
To analyze the efficacy between different mineralocorticoid receptor antagonists (MRAs) and epithelial sodium channel (ENaC) inhibitors in a network meta-analysis (NMA) framework, while also evaluating adverse events.
DESIGN
Systematic review and NMA.
DATA SOURCES AND METHODS
The systematic review and NMA was reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, MEDLINE, the Cochrane library, and Excerpta Medica database (EMBASE) were searched for randomized controlled trials (RCTs) involving adult patients with primary hyperaldosteronism until 23 June 2023. Studies that compared the efficacy and side effects of different medical treatments of primary hyperaldosteronism were included. The primary outcomes included the effect on blood pressure, serum potassium, and major adverse cardiovascular events. The secondary outcomes were adverse events related to MRAs (hyperkalemia and gynecomastia). Frequentist NMA and pairwise meta-analysis were conducted.
RESULTS
A total of 5 RCTs comprising 392 participants were included. Eplerenone, esaxerenone, and amiloride were compared to spironolactone and demonstrated comparable effect on the reduction of systolic blood pressure. In comparison to spironolactone, eplerenone exhibited a less pronounced effect on reducing diastolic blood pressure [-4.63 mmHg; 95% confidence interval (CI): -8.87 to -0.40 mmHg] and correcting serum potassium (-0.2 mg/dL; 95% CI: -0.37 to -0.03 mg/dL). Spironolactone presented a higher risk of gynecomastia compared with eplerenone (relative risk: 4.69; 95% CI: 3.58-6.14).
CONCLUSION
The present NMA indicated that the blood pressure reduction and potassium-correcting effects of the three MRAs may demonstrate marginal differences, with confidence levels in the evidence being very low. Therefore, further research is needed to explore the efficacy of these MRAs, especially regarding their impact on mortality and cardiovascular outcomes.
TRIAL REGISTRATION
PROSPERO (CRD: 42023446811).
PubMed: 38511069
DOI: 10.1177/20406223241239775 -
Journal of Pharmacological and... 2024The strategic and targeted use of an anesthetized canine cardiovascular model early in drug discovery enables a comprehensive cardiovascular and electrophysiological...
The strategic and targeted use of an anesthetized canine cardiovascular model early in drug discovery enables a comprehensive cardiovascular and electrophysiological assessment of potential safety liabilities and guides compound selection prior to initiation of chronic toxicological studies. An ideal model would enable exposure-response relationships to guide safety margin calculations, have a low threshold to initiate, and have quick delivery of decision quality data. We have aimed to profile compounds with diverse mechanism of actions (MoAs) of "non-QT" cardiovascular drug effects and evaluate the ability of nonclinical in vivo cardiovascular models to detect clinically reported effects. The hemodynamic effects of 11 drugs (atropine, itraconazole, atenolol, ivabradine, milrinone, enalaprilat, fasudil, amlodipine, prazosin, amiloride, and hydrochlorothiazide) were profiled in an anesthetized dog cardiovascular model. Derived parameters included: heart rate, an index of left ventricular contractility, mean arterial pressure, systemic vascular resistance, and cardiac output. Species specific plasma protein data was generated (human, dog) and utilized to calculate free drug concentrations. Using the anesthetized dog cardiovascular model, 10 of the 11 drugs displayed the predicted changes in CV parameters based on their primary MoAs and corresponding clinically described effects. Interestingly but not unexpected, 1 of 11 failed to display their predicted CV pattern which is likely due to a delay in pharmacodynamic effect that is beyond the duration of the experimental model (hydrochlorothiazide). The analysis from the current study supports the strategic use of the anesthetized dog model early in the drug discovery process for a comprehensive cardiovascular evaluation with good translation to human.
Topics: Dogs; Animals; Humans; Drug Evaluation, Preclinical; Hemodynamics; Heart Rate; Pharmaceutical Preparations; Heart Ventricles; Hydrochlorothiazide; Blood Pressure
PubMed: 38479593
DOI: 10.1016/j.vascn.2024.107497 -
International Journal of Surgery Case... Apr 2024Heterotopic ossification is forming a new bone in tissues that do not normally ossify. HO was first reported in 1901 by Askanazy and Lubarsh in a case report study. The...
INTRODUCTION AND IMPORTANCE
Heterotopic ossification is forming a new bone in tissues that do not normally ossify. HO was first reported in 1901 by Askanazy and Lubarsh in a case report study. The range of HO is wide from minute foci to large clinically significant ossification. The incidence of HO in abdominal scars is extremely low.
CASE PRESENTATION
We present an 84-year-old man referred to our hospital after an unsuccessful elective colostomy reversal in a local hospital. The colostomy was made for fecal diversion after sigmoidectomy due to treatment of sigmoid volvulus about three months ago. The patient had a past medical history of hypertension for 8 years under treatment of amiloride.
CLINICAL DISCUSSION
In general appearance, the patient was not ill or toxic. Vital signs were normal. Postoperatively Patient did not defecate. In his physical examination was not found abdominal tenderness or rebound tenderness. The patient underwent laparotomy which revealed significant retroperitoneal adhesion and colostomy was reversed. Accidentally was found a dense structure with bone-like consistency in the abdominal wall close to the scar was resected. The specimen Pathologic examination showed metaplastic bone deposition with mature bone trabeculae and heterotopic ossification was confirmed.
CONCLUSION
We report a rare case of HO that was identified at the abdominal wall. Heterotopic ossification can lead to serious complications. However, in symptomatic patients, surgical excision is an acceptable treatment, unlike in asymptomatic patients.
PubMed: 38460290
DOI: 10.1016/j.ijscr.2024.109469 -
BioRxiv : the Preprint Server For... Feb 2024The ENaC gamma subunit is essential for homeostasis of Na , K , and body fluid. Dual subunit cleavage before and after a short inhibitory tract allows dissociation of...
The ENaC gamma subunit is essential for homeostasis of Na , K , and body fluid. Dual subunit cleavage before and after a short inhibitory tract allows dissociation of this tract, increasing channel open probability (P ), . Cleavage proximal to the tract occurs at a furin recognition sequence ( RKRR in mouse). Loss of furin-mediated cleavage prevents activation of the channel by proteolysis at distal sites. We hypothesized that RKRR mutation to QQQQ ( ) in 129/Sv mice would reduce ENaC P , impair flow-stimulated flux of Na (J ) and K (J ) in perfused collecting ducts, reduce colonic amiloride-sensitive short circuit current (I ), and impair Na , K , and body fluid homeostasis. Immunoblot of mouse kidney lysates confirmed loss of a band consistent in size with the furin-cleaved proteolytic fragment. However, male mice on a low Na diet did not exhibit altered ENaC P or flow-induced J , though flow-induced J modestly decreased. Colonic amiloride-sensitive I in mice was not altered. males, but not females, exhibited mildly impaired fluid volume conservation when challenged with a low Na diet. Blood Na and K were unchanged on a regular, low Na , or high K diet. These findings suggest that biochemical evidence of gamma subunit cleavage should not be used in isolation to evaluate ENaC activity. Further, factors independent of gamma subunit cleavage modulate channel P and the influence of ENaC on Na , K , and fluid volume homeostasis in 129/Sv mice, .
PubMed: 38405735
DOI: 10.1101/2024.02.12.579964 -
Biochimica Et Biophysica Acta.... Apr 2024Type 2 inflammation in asthma develops with exposure to stimuli to include inhaled allergens from house dust mites (HDM). Features include mucus hypersecretion and the...
Type 2 inflammation in asthma develops with exposure to stimuli to include inhaled allergens from house dust mites (HDM). Features include mucus hypersecretion and the formation of pro-secretory ion transport characterised by elevated basal Cl current. Studies using human sinonasal epithelial cells treated with HDM extract report a higher protease activated receptor-2 (PAR-2) agonist-induced calcium mobilisation that may be related to airway sensitisation by allergen-associated proteases. Herein, this study aimed to investigate the effect of HDM on Ca signalling and inflammatory responses in asthmatic airway epithelial cells. Primary bronchial epithelial cells (hPBECs) from asthma donors cultured at air-liquid interface were used to assess electrophysiological, Ca signalling and inflammatory responses. Differences were observed regarding Ca signalling in response to PAR-2 agonist 2-Furoyl-LIGRLO-amide (2-FLI), and equivalent short-circuit current (I) in response to trypsin and 2-FLI, in ALI-asthma and healthy hPBECs. HDM treatment led to increased levels of intracellular cations (Ca, Na) and significantly reduced the 2-FLI-induced change of I in asthma cells. Apical HDM-induced Ca mobilisation was found to mainly involve the activation of PAR-2 and PAR-4-associated store-operated Ca influx and TRPV1. In contrast, PAR-2, PAR-4 antagonists and TRPV1 antagonist only showed slight impact on basolateral HDM-induced Ca mobilisation. HDM trypsin-like serine proteases were the main components leading to non-amiloride sensitive I and also increased interleukin-33 (IL-33) and thymic stromal lymphopoietin (TSLP) from asthma hPBECs. These studies add further insight into the complex mechanisms associated with HDM-induced alterations in cell signalling and their relevance to pathological changes within asthma.
Topics: Humans; Animals; Alarmins; Trypsin; Asthma; Epithelial Cells; Allergens; Pyroglyphidae
PubMed: 38367901
DOI: 10.1016/j.bbadis.2024.167079 -
Human Reproduction (Oxford, England) Apr 2024Whether and how do Na+/H+ exchangers (NHEs) regulate the physiological functions of human sperm?
STUDY QUESTION
Whether and how do Na+/H+ exchangers (NHEs) regulate the physiological functions of human sperm?
SUMMARY ANSWER
NHE-mediated flagellar intracellular pH (pHi) homeostasis facilitates the activation of the pH-sensitive, sperm-specific Ca2+ channel (CatSper) and the sperm-specific K+ channel (KSper), which subsequently modulate sperm motility, hyperactivation, flagellar tyrosine phosphorylation, and the progesterone (P4)-induced acrosome reaction.
WHAT IS KNOWN ALREADY
Sperm pHi alkalization is an essential prerequisite for the acquisition of sperm-fertilizing capacity. Different sperm functions are strictly controlled by particular pHi regulatory mechanisms. NHEs are suggested to modulate sperm H+ efflux.
STUDY DESIGN, SIZE, DURATION
This was a laboratory study that used samples from >50 sperm donors over a period of 1 year. To evaluate NHE action on human sperm function, 5-(N,N-dimethyl)-amiloride (DMA), a highly selective inhibitor of NHEs, was utilized. All experiments were repeated at least five times using different individual sperm samples or cells.
PARTICIPANTS/MATERIALS, SETTING, METHODS
By utilizing the pH fluorescent indicator pHrodo Red-AM, we detected alterations in single-cell pHi value in human sperm. The currents of CatSper and KSper in human sperm were recorded by the whole-cell patch-clamp technique. Changes in population and single-cell Ca2+ concentrations ([Ca2+]i) of human sperm loaded with Fluo 4-AM were measured. Membrane potential (Vm) and population pHi were quantitatively examined by a multimode plate reader after sperm were loaded with 3,3'-dipropylthiadicarbocyanine iodide and 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester, respectively. Sperm motility parameters were assessed by a computer-assisted semen analysis system. Tyrosine phosphorylation was determined by immunofluorescence, and sperm acrosome reaction was evaluated by Pisum sativum agglutinin-FITC staining.
MAIN RESULTS AND THE ROLE OF CHANCE
DMA-induced NHEs inhibition severely acidified the human sperm flagellar pHi from 7.20 ± 0.04 to 6.38 ± 0.12 (mean ± SEM), while the effect of DMA on acrosomal pHi was less obvious (from 5.90 ± 0.13 to 5.57 ± 0.12, mean ± SEM). The whole-cell patch-clamp recordings revealed that NHE inhibition remarkably suppressed alkalization-induced activation of CatSper and KSper. As a consequence, impairment of [Ca2+]i homeostasis and Vm maintenance were detected in the presence of DMA. During the capacitation process, pre-treatment with DMA for 2 h potently decreased sperm pHi, which in turn decreased sperm motility and kinetic parameters. Sperm capacitation-associated functions, including hyperactivation, tyrosine phosphorylation, and P4-induced acrosome reaction, were also compromised by NHE inhibition.
LARGE SCALE DATA
N/A.
LIMITATIONS, REASONS FOR CAUTION
This was an in vitro study. Caution should be taken when extrapolating these results to in vivo applications.
WIDER IMPLICATIONS OF THE FINDINGS
This study revealed that NHEs are important physiological regulators for human CatSper and KSper, which are indispensable for human sperm fertility, suggesting that malfunction of NHEs could be an underlying mechanism for the pathogenesis of male infertility.
FUNDING/COMPETING INTEREST(S)
This work was supported by the National Natural Science Foundation of China (32271167 and 81871202 to X.Z.), Jiangsu Innovation and Entrepreneurship Talent Plan (JSSCRC20211543 to X.Z.), the Social Development Project of Jiangsu Province (No. BE2022765 to X.Z.), the Society and livelihood Project of Nantong City (No. MS22022087 to X.Z.), and the Natural Science Foundation of Jiangsu Province (BK20220608 to H.K.). The authors have no competing interests to declare.
Topics: Humans; Male; Acid-Base Equilibrium; Calcium; Calcium Channels; Calcium Signaling; Semen; Sperm Motility; Spermatozoa; Tyrosine; Sperm Tail; Sodium-Hydrogen Exchangers
PubMed: 38366201
DOI: 10.1093/humrep/deae020 -
European Journal of Pharmaceutics and... Apr 2024Over the last 10 years there is an increasing need for the design of personalised medicines at the point of care (PoC) that meet the specific needs of individual...
Over the last 10 years there is an increasing need for the design of personalised medicines at the point of care (PoC) that meet the specific needs of individual patients. A plethora of technologies has been introduced for making affordable personalised pharmaceutical products, which however, do not address manufacturing and regulatory challenges. Here we introduce a novel ultra-compact tablet press which was used for the design and compression of rosuvastatin-aspirin and amiloride-lysonipril bilayer tablets respectively. By applying precision dosing, it was feasible to manufacture tablets of different dose strengths and control features such as hardness, friability and disintegration times. The compaction of on-demand personalised multidrug pills that meet quality standards could revolutionised the treatment of patients at the point of care.
Topics: Humans; Chemistry, Pharmaceutical; Point-of-Care Systems; Tablets; Technology, Pharmaceutical; Physical Phenomena; Drug Compounding
PubMed: 38360119
DOI: 10.1016/j.ejpb.2024.114220 -
The Journal of Physiology Feb 2024Paraoxonase 3 (PON3) is expressed in the aldosterone-sensitive distal nephron, where filtered Na is reabsorbed mainly via the epithelial Na channel (ENaC) and Na...
Paraoxonase 3 (PON3) is expressed in the aldosterone-sensitive distal nephron, where filtered Na is reabsorbed mainly via the epithelial Na channel (ENaC) and Na -coupled co-transporters. We previously showed that PON3 negatively regulates ENaC through a chaperone mechanism. The present study aimed to determine the physiological role of PON3 in renal Na and K homeostasis. Pon3 knockout (KO) mice had higher amiloride-induced natriuresis and lower plasma [K ] at baseline. Single channel recordings in split-open tubules showed that the number of active channels per patch was significantly higher in KO mice, resulting in a higher channel activity in the absence of PON3. Although whole kidney abundance of ENaC subunits was not altered in Pon3 KOs, ENaC gamma subunit was more apically distributed within the connecting tubules and cortical collecting ducts of Pon3 KO kidneys. Additionally, small interfering RNA-mediated knockdown of PON3 in cultured mouse cortical collecting duct cells led to an increased surface abundance of ENaC gamma subunit. As a result of lower plasma [K ], sodium chloride co-transporter phosphorylation was enhanced in the KO kidneys, a phenotype that was corrected by a high K diet. Finally, PON3 expression was upregulated in mouse kidneys under dietary K restriction, potentially providing a mechanism to dampen ENaC activity and associated K secretion. Taken together, our results show that PON3 has a role in renal Na and K homeostasis through regulating ENaC functional expression in the distal nephron. KEY POINTS: Paraoxonase 3 (PON3) is expressed in the distal nephron of mouse kidneys and functions as a molecular chaperone to reduce epithelial Na channel (ENaC) expression and activity in heterologous expression systems. We examined the physiological role of PON3 in renal Na and K handling using a Pon3 knockout (KO) mouse model. At baseline, Pon3 KO mice had lower blood [K ], more functional ENaC in connecting tubules/cortical collecting ducts, higher amiloride-induced natriuresis, and enhanced sodium chloride co-transporter (NCC) phosphorylation. Upon challenge with a high K diet, Pon3 KO mice had normalized blood [K ] and -NCC phosphorylation but lower circulating aldosterone levels compared to their littermate controls. Kidney PON3 abundance was altered in mice under dietary K loading or K restriction, providing a potential mechanism for regulating ENaC functional expression and renal Na and K homeostasis in the distal nephron.
Topics: Mice; Animals; Amiloride; Aryldialkylphosphatase; Epithelial Sodium Channels; Aldosterone; Sodium Chloride; Sodium; Nephrons; Symporters
PubMed: 38345534
DOI: 10.1113/JP285034