Effects of oral losartan administration on homeostasis of articular cartilage and bone in a rabbit model

Background and aims

Previous work has shown that oral losartan can enhance microfracture-mediated cartilage repair in a rabbit osteochondral defect injury model. In this study, we aimed to determine whether oral losartan would have a detrimental effect on articular cartilage and bone homeostasis in the uninjured sides.

Methods

New Zealand rabbits were divided into 4 groups including normal uninjured (Normal), contralateral uninjured side of osteochondral defect (Defect), osteochondral defect plus microfracture (Microfracture) and osteochondral defect plus microfracture and losartan oral administration (10 mg/kg/day) (Losartan). Rabbits underwent different surgeries and treatment and were sacrificed at 12 weeks. Both side of the normal group and uninjured side of treatment groups tibias were harvested for Micro-CT and histological analysis for cartilage and bone including H&E staining, Herovici's staining (bone and cartilage) Alcian blue and Safranin O staining (cartilage) as well as immunohistochemistry of losartan related signaling pathways molecules for both cartilage and bone.

Results

Our results showed losartan oral treatment at 10 mg/kg/day slightly increase Alcian blue positive matrix as well as decrease collagen type 3 in articular cartilage while having no significant effect on articular cartilage structure, cellularity, and other matrix. Losartan treatment also did not affect angiotensin receptor type 1 (AGTR1), angiotensin receptor type 2 (AGTR2) and phosphorylated transforming factor β1 activated kinase 1 (pTAK1) expression level and pattern in the articular cartilage. Furthermore, losartan treatment did not affect microarchitecture of normal cancellous bone and cortical bone of tibias compared to normal and other groups. Losartan treatment slightly increased osteocalcin positive osteoblasts on the surface of cancellous bone and did not affect bone matrix collagen type 1 content and did not change AGTR1, AGTR2 and pTAK1 signal molecule expression.

Conclusion

Oral losartan used as a microfracture augmentation therapeutic does not have significant effect on uninjured articular cartilage and bone based on our preclinical rabbit model. These results provided further evidence that the current regimen of using losartan as a microfracture augmentation therapeutic is safe with respect to bone and cartilage homeostasis and support clinical trials for its application in human cartilage repair.

Taurine improves neuron injuries and cognitive impairment in a mouse Parkinson's disease model through inhibition of microglial activation

Clinical and experimental findings support the view that activation of hippocampus microglia through NADPH oxidase contributes to cognitive impairment in Parkinson's disease (PD). Taurine, an antioxidant, displays an exclusive physical property on brain function, such as learning and memory. To date, the role of taurine in improving cognitive impairment in PD is not fully uncovered. Hence, we evaluated the protective effect of taurine on cognitive ability and explored the related mechanism in the model built by paraquat and maneb (P + M)-induced PD mice. Then the ability of learning and memory was observed by Morris water maze, neuron loss was evaluated by immunohistochemistry in hippocampus, the level of postsynaptic density 95 (PSD95) and microglia activation was assessed by immunostaining, the molecules (gp91phox, p47phox, mac1, p-Src/Src and p-Erk/Erk) were examined by western blot. The results showed that taurine could alleviate the impairments in learning and memory induced by P + M injection in mice (decreased escape latency on day 4, P < 0.01; decreased swimming distance on day 4, P < 0.05; increased percent time in target quadrant, P < 0.05), corresponding with activation of microglia (decreased IBa-1 density, P < 0.001; decreased the protein expression of p47phox, P < 0.05; decreased protein expression of gp91phox, P < 0.01; decreased p-Src/Src, P < 0.01; decreased p-Erk/Erk, P < 0.01; decreased mac 1, P < 0.01), decreased neuron loss (increased number of NeurN+ neuron, P < 0.001; increased protein expression of NeruN, P < 0.01; decreased protein expression of caspase 3, P < 0.01) and increased PSD95 level in hippocampus (P < 0.01). The results indicated that mac1 and Src-Erk signaling was involved in increased NADPH oxidase expression in hippocampus microglia of P + M mice, and taurine could improve injuries in learning and memory through mac1 reduction. The new findings in mac1 triggering hippocampal microglia NADPH oxidase through Src/Erk pathway of the present study might provide a therapy target for PD.

Impact of the COVID-19 Pandemic on Stroke Epidemiology and Clinical Stroke Practice in the US

Introduction

To examine the impact of the COVID-19 pandemic on stroke, the number of stroke patients, time since last known well (LKW), morbidity, and mortality of stroke patients in Southwest Healthcare System (SHS), California (CA) and the United States (US) were analyzed during 2019 and compared to 2020. Our hypothesis is that there are regional differences in stroke outcome depending on location during the COVID-19 study period which influences stroke epidemiology and clinical stroke practice.

Methods

The American Heart Association's ‘Get with the Guidelines’ (GWTG) database was used to evaluate the following categories: code stroke, diagnosis of stroke upon discharge, inpatient mortality, modified Rankin Score (mRS) upon discharge (morbidity), and time since last known well (LKW). Stroke registry data from February through June 2019 and 2020 were collected for retrospective review.

Results

The total number of strokes decreased in the US and CA, but increased in SHS during the COVID-19 study period. The US and SHS demonstrated no change in stroke mortality, but CA demonstrated a higher stroke mortality during the COVID-19 pandemic. There was greater loss of independence with increased stroke morbidity in the US during the COVID-19 pandemic. There was a significant increase in time since LKW in the US and SHS, and an increase trend in time since LKW in CA during the COVID-19 study period.

Discussion

To understand the impact of the COVID-19 pandemic on stroke epidemiology, we propose that all stroke inpatients should receive a SARS-CoV-2 detection test and this result be entered into the GWTG database. We demonstrate that the regional distribution of stroke mortality in the US changed during the COVID-19 study period, with increased stroke mortality in CA. Stroke morbidity throughout the US was significantly worse during the COVID-19 pandemic. We propose methods to address the impact of the COVID-19 pandemic on clinical stroke practice such as the use of mobile stroke units, clinical trials using anti-inflammation drugs on SARS-CoV-2 positive stroke patients, and COVID stroke rehabilitation centers.

Synthesis of chiral (tetrazolyl)methyl-containing acrylates via silicon-induced organocatalytic kinetic resolution of Morita–Baylis–Hillman fluorides

A new approach for the asymmetric installation of a (tetrazolyl)methyl group via Si/F activation using organocatalytic kinetic resolution of racemic MBH-fluorides.

Evaluation of a Pharmacokinetic Interaction between Telmisartan and Chlorthalidone in Healthy Male Adult Subjects

BACKGROUND AND OBJECTIVE

Combination therapy is recommended for the effective management of hypertension according to most treatment guidelines, including those of the US Joint National Committee. Therefore, pharmacokinetic drug interactions are an important issue in combination therapy for hypertension. In this study, the pharmacokinetic properties of telmisartan and chlorthalidone were evaluated to investigate their pharmacokinetic interactions in healthy subjects.

METHODS

Two separate, randomized, multiple-dose, two-period, one-sequence studies were conducted. In study A, 43 participants received 80 mg of telmisartan orally for 7 days, and were then administered oral chlorthalidone 25 mg for 14 days (days 8-21), coadministered with 80 mg of telmisartan from day 15. In study B, 14 participants received oral chlorthalidone (25 mg) for 13 days, followed by coadministration with 80 mg of telmisartan orally for 7 days.

RESULTS

The geometric mean ratios (GMRs) (90 % confidence intervals [CIs]) of the maximum plasma concentration (C max,ss) and area under the concentration-time curve for the dosing interval at steady state (AUCτ,ss) of telmisartan (with and without chlorthalidone) were 1.018 (0.861-1.203) and 1.099 (1.015-1.190), respectively. For chlorthalidone (with/without telmisartan), the GMRs (90 % CIs) for C max,ss and AUCτ,ss were 0.996 (0.922-1.075) and 0.992 (0.925-1.064), respectively. The GMRs and 90 % CIs for telmisartan and chlorthalidone were all within the 0.80-1.25 range.

CONCLUSION

Thus, in this study, there was no significant pharmacokinetic interaction between telmisartan and chlorthalidone. CLINICALTRIAL.

GOV IDENTIFIER

NCT01806363.

Enhanced absorption and bioavailability of hydrochlorothiazide by Chinese medicines in the Zhenju antihypertensive compound

OBJECTIVES

This study was performed to investigate the influence of traditional Chinese medicines in the Zhenju antihypertensive compound (ZJAHC) on the oral absorption of hydrochlorothiazide (HCT) both in vitro and in vivo.

METHODS

Caco-2 cells and the in situ closed loop system were used to investigate the possible mechanism of the Chinese-Western medicine interaction on the transepithelial transport and uptake of HCT. The influence of TCMs on the pharmacokinetics and bioavailability of HCT was also studied to reveal the possible interaction in vivo.

KEY FINDINGS

In an in situ intestinal perfusion study, the cumulative amount of HCT of ZJAHC group (506.05 μg ± 96.03) was 2.2-fold, 2.18-fold and 1.38-fold higher compared to that of the HCT group (228.29 μg ± 23.39), HCT-clonidine (CLO) group (232.13 ± 54.79 μg) and HCT-rutin (RT) group (366.08 ± 21.97 μg), respectively, after 120 min of perfusion. A pharmacokinetic analysis showed a significant increase in area under the plasma concentration-time curve (AUC) of HCT in the ZJAHC group by 2.14-fold, 2.01-fold and 1.32-fold compared to the HCT, HCT-CLO and HCT-RT groups, respectively. As a P-gp inhibitor, RT could contribute to the enhanced oral absorption of HCT in ZJAHC.

CONCLUSION

The combination of traditional Chinese medicines and chemical drugs may provide a promising strategy and unique advantages to reduce the dosage and side effects of chemical drugs while maintaining an effect on hypertension.

Combination therapy with losartan/hydrochlorothiazide for blood pressure reduction and goal attainment in a real-world clinical setting in Japan

Objective:

When physicians prescribe a new antihypertensive drug, they do not know the extent of the drug’s effect on lowering blood pressure. To resolve this dilemma, a Web-based program was constructed for real-time entry and analysis of treatment. This observational study evaluated the efficacy of losartan/hydrochlorothiazide (Lo/HCTZ) in lowering blood pressure (BP) and achieving BP target values.

Methods:

Physicians prescribed Lo/HCTZ for patients with hypertension who failed to achieve target BP values of < 140/90 mmHg and < 130/80 mmHg in patients with diabetes or chronic kidney disease, respectively, with antihypertensive drugs including an angiotensin receptor blocker.

Results:

From December 2006 to December 2009, the data of 88,254 patients were entered into this database, and the data of 24,825 subjects were analyzed. At the first visit, a total of 88,254 patients received a first prescription of Lo/HCTZ daily. Among these, at the end of the present analysis, 24,825 (28%) outpatients had a follow-up visit at 1 month and 20,726 (23%) outpatients had a follow-up visit at 6 months. The prevalence of hypertensive patients achieving systolic blood pressure (SBP) control (< 140 mmHg) increased over time from 6.9% to 54.3% in females and 6.1% to 52.3% in males ( p < 0.05). At the start of the study, the levels of SBP were significantly highest in the eldest patients (≥ 75 years) followed by the group of 65–75 years and lowest in the youngest patients (≤ 64 years). However, at the end of the study, there were no differences in levels of SBP among the three groups.

Conclusions:

This Web-based system may provide useful information when a new drug is first released into the market. Treatment with Lo/HCTZ enabled a substantial proportion of hypertensive patients to achieve the recommended goal of < 140/90 mmHg.

Comparison of the effects of angiotensin II receptor antagonist monotherapy and combination therapy with a diuretic on cardiac function in spontaneously hypertensive rats

OBJECTIVE

Losartan, an angiotensin II receptor blocker (ARB), has been reported to promote sodium excretion and show an enhanced antihypertensive effect when used in combination with hydrochlorothiazide (HCTZ). We investigated the effects of losartan monotherapy and combination therapy together with HCTZ on cardiac function in hypertensive rats using echocardiography.

METHODS

Spontaneously hypertensive rats (n = 21) fed on high-salt diet (8 % NaCl) for 13 weeks were randomly assigned to rats without medication (HS, n = 7), those medicated with ARB (ARB, losartan 30 mg/kg/day, n = 8), and those with ARB and HCTZ (ARB + HCTZ, losartan 30 mg/kg/day + HCTZ 10 mg/kg/day, n = 6). Blood pressure measurements and echocardiography were performed at 13, 17, and 29 weeks of age. After the end of the protocol, the proportion of cardiac muscle fibrosis was measured histologically.

RESULTS

In the HS group, blood pressure and left ventricular mass/body weight (LV mass/BW) increased, and % fractional shortening (%FS) and early diastolic mitral annular velocity (e') decreased significantly with age. In the ARB group, although blood pressure and %FS were maintained, LV mass/BW increased with age as in the HS group, and e' decreased. In the ARB + HCTZ group, blood pressure decreased and LV mass/BW, %FS, and e' were maintained. The progression of myocardial fibrosis was clearly prevented in rats treated with ARB.

CONCLUSION

ARB was shown to inhibit systolic disorder and myocardial fibrosis in hypertensive rats. Combination therapy proved to be more effective than monotherapy and is also effective in inhibiting diastolic disorders.

Clinical experience in treating hypertension with fixed-dose combination therapy: angiotensin II receptor blocker losartan plus hydrochlorothiazide

The goal of antihypertensive treatment is to reduce cardiovascular and cerebrovascular events associated with high blood pressure. A combination therapy with different antihypertensive agents is more successful than monotherapy in most hypertensive patients, with the added advantage of a better safety profile. Therefore, treatment of hypertensive patients with fixed-dose combination therapy consisting of the angiotensin II receptor blocker losartan along with hydrochlorothiazide (HCTZ) has several potential benefits over monotherapy with each individual component. It provides more effective blood pressure control, a reduction in the likelihood of adverse effects and facilitation of patient compliance due to a simple once-daily regimen. One of the advantages of the combination of losartan with HCTZ is the potential reduction in HCTZ-induced metabolic disorders; in particular, this combination can have attractive benefits for patients of hyperuricemia. Losartan plus HCTZ fixed-dose combination therapy is frequently recommended for the treatment of hypertension and lowers blood pressure in mild-to-moderate and even severe hypertensive patients to a level comparable with other classes of antihypertensive agents in combination with HCTZ. Fixed-dose combination therapy with losartan plus HCTZ is a logical choice as antihypertensive therapy for patients in whom combination therapy is necessary to achieve additional blood pressure reduction.