Effects of losartan and l-serine in a mouse liver fibrosis model

Comparative Effects of Crocin and Losartan on RAGE, TGF-β, TNF-α Gene Expression and Histopathological Changes of the Liver Tissue in Rats With Diabetes

BACKGROUND AND OBJECTIVES

AGEs, via RAGE, increase the development of hyperglycemia-induced liver damage, and blocking this axis is associated with a reduction in liver disease progression. The goal of this study was to determine how crocin and losartan influenced RAGE, TNF-α and TGF-β gene expression in diabetic rats, as well as histological changes in liver tissue.

MATERIALS AND METHODS

Diabetes was induced in 40 male Wistar rats using Streptozotocin (50 mg/kg, IP). There were five groups of rats: diabetic and healthy groups, diabetic rats given crocin (50 mg/kg), losartan (25 mg/kg) and both (crocin + Los). Serum glucose, ALT and AST levels were measured 4 weeks later. qPCR was used to examine the TNF-α, TGF-β and RAGE gene expression in liver tissue.

RESULTS

Crocin was found to be effective in lowering FBG in the diabetes group. The serum levels of ALT and AST decreased in all treated groups, but this decrease was significant in the crocin + Los group (p < 0.05). The relative expression of RAGE, TNF-α and TGF-β genes was significantly higher in the diabetes group compared to the healthy group. The expression of these genes decreased in groups treated with crocin and Losartan compared to the diabetes group. The highest reduction in RAGE and TGF-β gene expression was reported in those treated with crocin + Los. Histopathology results showed that the diabetes group had more bile ducts and necrosis than the healthy control group, which had no tissue changes. Hepatocyte degeneration, bile duct proliferation, inflammatory changes and hepatocyte necrosis were mild in the treated groups, but no hepatocyte necrosis was observed in the crocin + Los group.

CONCLUSION

Crocin may be a feasible therapeutic agent for treating diabetes and its symptoms when combined with pharmaceutical medications. Human research is still needed to reach clear conclusions.

Serine metabolism in aging and age-related diseases

Non-essential amino acids are often overlooked in biomedical research; however, they are crucial components of organismal metabolism. One such metabolite that is integral to physiological function is serine. Serine acts as a pivotal link connecting glycolysis with one-carbon and lipid metabolism, as well as with pyruvate and glutathione syntheses. Interestingly, increasing evidence suggests that serine metabolism may impact the aging process, and supplementation with serine may confer benefits in safeguarding against aging and age-related disorders. This review synthesizes recent insights into the regulation of serine metabolism during aging and its potential to promote healthy lifespan and mitigate a spectrum of age-related diseases.

Safety and tolerability of losartan to treat recessive dystrophic epidermolysis bullosa in children (REFLECT): an open-label, single-arm, phase 1/2 trial

Background

Recessive dystrophic epidermolysis bullosa (RDEB) is a skin fragility disorder characterised by life-long mechanically induced skin blistering, fibrosis-driven pseudosyndactyly, and multi-organ involvement. Preclinical studies have suggested mitigated progression by angiotensin II type I receptor blockade through losartan. We aimed to determine the safety and tolerability of systemic losartan treatment among children with RDEB, and to obtain initial data on its clinical benefit.

Methods

We conducted an open-label, single-arm, phase 1/2 trial at the Medical Center-University of Freiburg, Germany. Children with molecularly-confirmed RDEB, aged 2-16 years (starting from the 25th month of life) were eligible. Key exclusion criteria comprised anaemia with haemoglobin <8 g/dl; hypotension (defined as age-related systolic blood pressure under the 5th percentile); cardiologic contraindications, requirement for any medications that are likely to cause interactions with losartan; renal artery stenosis or renal insufficiency with creatinine clearance <30 ml/min; severe liver failure; severe, untreated electrolyte disturbances; history of cancer or chronic viral infections; hypersensitivity to losartan or any of the excipients and known or persistent abuse of medication, drugs, or alcohol. Treatment duration with losartan comprised 10 months, encompassing 16 weeks up-dosing of losartan, 24 weeks full dose losartan (final target dose of 1.4 mg/kg), and 4 weeks losartan tapering, followed by 12 weeks follow-up without losartan. The primary endpoint was occurrence of a serious safety concern, defined as one of the following side effects of losartan: clinically relevant severe hypotension, immediate hypersensitivity reactions to the drug or clinical relevant severe hypo- and hyperkalaemia. EB-specific scores (the EBDASI activity and damage score, Birmingham Epidermolysis Bullosa Severity Score (BEBS)) and other clinical outcome parameters were evaluated at five clinical visits as secondary outcomes: pain (Wong-Baker FACES Scale for pain), quality of life (Quality Of Life in EB [QOLEB] questionnaire and Children's Dermatology Life Quality Index [CDLQI]), itch (Itch Assessment Scale for the Paediatric Burn Patients), dysphagia (Mayo Dysphagia Questionnaire-day 30 [MDQ-30]), pseudosyndactyly progression (our own morphometric scoring instrument), and hand function (Score of Colville and Terrill). All analyses (safety and efficacy) were performed in the safety population, defined as participants who received at least one dose of trial medication with losartan. This trial is registered with EudraCT, 2015-003670-32.

Findings

Between Jul 28, 2017, and Feb 12, 2021, 29 children were enrolled. Of those 27 received the full treatment. Losartan was well tolerated, no treatment-related severe complications leading to a serious safety concern occurred. The patients revealed improvement in the RDEB clinical scores, namely a mean reduction at week 40 of -7.36 points (95%-CI: -16.13 to 1.41) in the EBDASI activity score and -10.50 points (95%-CI: -20.81 to -0.19) in the EBDASI damage score, while the Children's Dermatology Life Quality Index rose by 2.64 points (95%-CI: -4.55 to -0.90). Similar to the EBDASI score, the BEBS showed a mean reduction of -3 points, 95%-CI: -0.21 to -5,79, P = 0.036). In the Wong-Baker FACES Scale for Pain an improvement of at least one level was identified for 9 of 28 patients between baseline and at month 9 (95%-CI: 15.9%-52.4%; P = 0.57). Regarding the Quality of Life in EB Score, five of 28 patients showed an improvement in the total scale of at least one level at month 9 (95%-CI: 6.1%-36.9%; P = 0.71). With the Itch assessment scale for the paediatric burn patients an improvement of at least one level could be observed in 12 of 28 patients (95%-CI: 24.5%-62.8%; P = 0.24). The MDQ-30 showed no relevant difference at 9 months after treatment start, as compared to baseline. We observed improvement of finger span with our own morphometric scoring instrument of pseudosyndactyly progression, revealing an increase of the maximal distance between thumb and index finger at month 9 by 6.92 mm, 95%-CI [3.48, 10.37] P = 0.0009. With the Hand function assessment score of Colville and Terrill, an improvement of at least one level was documented for 3 of 28 patients, i.e., 10.7% (95%-CI: 2.3%-28.2%; P = 0.63).

Interpretation

Our results suggest that losartan was well tolerated by children with RDEB, and provide preliminary evidence that it may reduce disease burden. Further research with larger sample sizes and longer durations is needed to establish the treatment's long-term efficacy and safety.

Funding

Debra International, the Department of Dermatology, Medical Center-University of Freiburg (Berta-Ottenstein Advanced Clinician Scientist Program of the Medical Faculty), and the German Research Foundation.

Liver-Targeting Composite Nanocarrier Delivery System Based on Chitosan Nanoparticles and Phospholipid Complexes

Liver fibrosis is mainly caused by excessive accumulation of extracellular matrix and structural changes in the liver, ultimately leading to cirrhosis if left untreated. Reducing hyaluronan synthesis by inhibiting hyaluronic acid deposition or regulating the expression of hyaluronic synthase can ameliorate liver fibrosis symptoms. In this study, we aimed to improve the bioavailability and liver-targeting capacity of hydroxymethyl coumarin (4-MU) using a newly developed phospholipid complex chitosan nanoparticle (4-MU PC/CNP) optimized using the Box-Behnken design. The composite nanocarrier delivery system was formulated using solvent evaporation technology, and formulation and process parameters were evaluated. Furthermore, 4-MU PC/CNPs and their pharmacokinetics were characterized. The established 4-MU PC/CNPs had an average particle size of 153.07 ± 0.29 nm, a polydispersity index value of 0.383, and a positive zeta potential of ∼35.4 mV. Compared with 4-MUs, 4-MU PC/CNPs exhibited significantly improved water solubility, faster plasma clearance and tissue distribution, and better liver targeting. Pharmacokinetic analysis showed that the oral bioavailability of 4-MU in 4-MU PC/CNPs was significantly higher than that of simple 4-MU. In conclusion, 4-MU PC improved drug lipid (oil-water distribution coefficient of 1.31 ± 0.03) and water solubilities (2.05 times the drug substance). 4-MU PC/CNPs significantly improved 4-MU oral bioavailability, representing a promising approach for enhancing drug solubility. This study demonstrates that the targeting parameters of 4-MU PC/CNPs in the liver were all greater than 1, indicating that they specifically targeted the liver, thereby potentially alleviating liver fibrosis.

Shen Qi Wan attenuates renal interstitial fibrosis through upregulating AQP1

Renal interstitial fibrosis (RIF) is the crucial pathway in chronic kidney disease (CKD) leading to the end-stage renal failure. However, the underlying mechanism of Shen Qi Wan (SQW) on RIF is not fully understood. In the current study, we investigated the role of Aquaporin 1 (AQP1) in SQW on tubular epithelial-to-mesenchymal transition (EMT). A RIF mouse model induced by adenine and a TGF-β1-stimulated HK-2 cell model were etablished to explore the involvement of AQP 1 in the protective effect of SQW on EMT in vitro and in vivo. Subsequently, the molecular mechanism of SQW on EMT was explored in HK-2 cells with AQP1 knockdown. The results indicated that SQW alleviated kidney injury and renal collagen deposition in the kidneys of mice induced by adenine, increased the protein expression of E-cadherin and AQP1 expression, and decreased the expression of vimentin and α-smooth muscle actin (α-SMA). Similarly, treatmement with SQW-containing serum significantly halted EMT process in TGF-β1 stimulated HK-2 cells. The expression of snail and slug was significantly upregulated in HK-2 cells after knockdown of AQP1. AQP1 knockdown also increased the mRNA expression of vimentin and α-SMA, and decreased the expression of E-cadherin. The protein expression of vimentin increased, while the expression of E-cadherin and CK-18 significantly decreased after AQP1 knockdown in HK-2 cells. These results revealed that AQP1 knockdown promoted EMT. Furthermore, AQP1 knockdown abolished the protective effect of SQW-containing serum on EMT in HK-2 cells. In sum, SQW attentuates EMT process in RIF through upregulation of the expression of AQP1.

A Substituted-Rhodamine-Based Reversible Fluorescent Probe for In Vivo Quantification of Glutathione

Quantifying glutathione (GSH) in cells and organisms is of great significance for understanding the mechanism of oxidative stress in various physiological and pathological processes. However, the quantification by fluorescence bioimaging in living tissues has much stricter requirements than the "Petri dish"-cultured cells in flat plates. Based on the evaluation of the electronic structure and steric hindrance-tuned reactivity of phospha-substituted rhodamine with GSH, a reversible Förster resonance energy transfer (FRET) probe ZpSiP with a distinct performance (K_d =4.9 mM, t_1/2 =0.57 s, k=81 M^-1  s^-1 ) is developed for real time quantifying GSH in living cells. Furthermore, the near-infrared (NIR) probe succeeded in sensitively tracking the dynamics of GSH in the real organisms bearing tumors, chronic renal failure, and liver fibrosis for unveiling the related pathological processes. We believe that the advance in chemistry with quantitative analysis methods will initiate more promising progress and broad applications.

Serum metabolomics strategy for investigating the hepatotoxicity induced by different exposure times and doses of Gynura segetum (Lour.) Merr. in rats based on GC-MS

Gynura segetum (Lour.) Merr. (GS), has been widely used in Chinese folk medicine and can promote circulation, relieve pain and remove stasis. In recent years, the hepatotoxicity caused by GS has been reported, however its mechanism is not fully elucidated. Metabolomic techniques are powerful means to explore the toxicological mechanism and therapeutic effects of traditional Chinese medicine. The purpose of this study was to establish a serum metabolomics method based on Gas Chromatography-Mass Spectrometry (GC-MS) to explore the hepatotoxicity mechanism of different exposure times and doses of GS in rats. Sprague Dawley (SD) rats were administered daily with distilled water, 7.5 g kg^-1 GS, or 15 g kg^-1 GS by intragastrical gavage for either 10 or 21 days. The methods adopted included enzyme-linked immunosorbent assay (ELISA), Hematoxylin and Eosin (H&E) staining and GC-MS-based serum metabolomics. Serum biochemistry analysis showed that the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglycerides (TG), total bilirubin (TBIL) and total bile acid (TBA) significantly (P < 0.05) increased while the levels of albumin (ALB) and high-density lipoprotein (HDL) significantly (P < 0.05) decreased in GS-treated groups, compared with the control group. Interestingly, the ALT, AST, TG and ALB levels changed in a time- and dose-dependent manner. The results of H&E staining showed the degree of liver damage after administration of GS gradually deepened with the extension of administration time and the increase of the dose. According to the results of metabolomics analysis, 26 differential metabolites were identified, which were involved in 8 metabolic pathways including phenylalanine metabolism, glyoxylic acid and dicarboxylic acid metabolism and so on. Meanwhile, the number of differential metabolites in different GS-treated groups was associated with GS exposure time and dose. Therefore, we concluded that GS might induce hepatotoxicity depending on the exposure time and dose.

Angiotensin receptor blocker alleviates liver fibrosis by altering the mechanotransduction properties of hepatic stellate cells

Angiotensin receptor blockers have been reported to be beneficial to liver fibrosis, but the relevant molecular and cellular mechanisms remain unclear. We herein investigated whether low-dose angiotensin receptor blocker alleviated liver fibrosis through mechanotransduction regulation. Hydrostatic pressure-induced liver fibrosis model was established in mice by ligating partially the inferior vena cava, and then randomly received a very low dose of losartan (0.5 mg/kg) or placebo treatment for 8 weeks. We found that losartan administration interfered the expression of several mechanotransductive molecules, and effectively alleviated liver fibrosis. Using a commercial device, we further confirmed that ex vivo loading of hepatic stellate cells to 50 mmHg hydrostatic pressure for 24 h significantly upregulated RhoA, ROCK, AT1R, and p-MLC2, which was effectively attenuated by adding 10 nM losartan in medium. Our in vivo and ex vivo experimental data suggest that low-dose angiotensin receptor blockers may alleviate hydrostatic pressure-induced liver fibrosis by altering the mechanotransduction properties of hepatic stellate cells.NEW & NOTEWORTHY Our ex vivo and in vivo experiments clearly indicated that low-dose losartan alleviated liver fibrosis, likely by modulating the mechanotransduction properties of HSCs. Uncovering the biomechanical signaling pathway of ARB treatment on liver fibrosis will be helpful to develop novel molecular targeting therapy for liver diseases.