Hydroxyproline as a Biomarker in Liver Disease

Strategic outline of interventions targeting extracellular matrix for promoting healthy longevity

The extracellular matrix (ECM), composed of interlinked proteins outside of cells, is an important component of the human body that helps maintain tissue architecture and cellular homeostasis. As people age, the ECM undergoes changes that can lead to age-related morbidity and mortality. Despite its importance, ECM aging remains understudied in the field of geroscience. In this review, we discuss the core concepts of ECM integrity, outline the age-related challenges and subsequent pathologies and diseases, summarize diagnostic methods detecting a faulty ECM, and provide strategies targeting ECM homeostasis. To conceptualize this, we built a technology research tree to hierarchically visualize possible research sequences for studying ECM aging. This strategic framework will hopefully facilitate the development of future research on interventions to restore ECM integrity, which could potentially lead to the development of new drugs or therapeutic interventions promoting health during aging.

A new cirrhotic animal protocol combining carbon tetrachloride with methotrexate to address limitations of the currently used chemical-induced models

Background: Chemically induced cirrhotic animal models are commonly used. However, they have limitations such as high mortalities and low yield of cirrhotic animals that limit their uses. Aims: To overcome limitations of the chemically induced cirrhotic animal model via combined administration of methotrexate (MTX) with CCl₄ and decrease their commonly used doses depending on the proposed synergetic cirrhotic effect. Methods: Rats were divided into six groups: normal (4 weeks), normal (8 weeks), MTX, CCl₄ (4 weeks), CCl₄ (8 weeks), and MTX + CCl₄ (4 weeks) groups. Animals' hepatic morphology and histopathological characterization were explored. Hepatic Bcl2 and NF-κB-p65 tissue contents were determined using the immunostaining technique, and hepatic tissue damage, oxidative status, and inflammatory status biochemical parameters were determined. Results: CCl₄ + MTX combined administration produced prominent cirrhotic liver changes, further confirmed by a substantial increase in oxidative stress and inflammatory parameters, whereas mortalities were significantly lower than in other treated groups. Conclusion: The present study introduced a new model that can significantly improve the major limitations of chemically induced cirrhotic animal models with new pathological features that mimic human cirrhosis. Compared to other chemically induced methods, the present model can save time, cost, and animal suffering.

Multi-omic rejuvenation of naturally aged tissues by a single cycle of transient reprogramming

The expression of the pluripotency factors OCT4, SOX2, KLF4, and MYC (OSKM) can convert somatic differentiated cells into pluripotent stem cells in a process known as reprogramming. Notably, partial and reversible reprogramming does not change cell identity but can reverse markers of aging in cells, improve the capacity of aged mice to repair tissue injuries, and extend longevity in progeroid mice. However, little is known about the mechanisms involved. Here, we have studied changes in the DNA methylome, transcriptome, and metabolome in naturally aged mice subject to a single period of transient OSKM expression. We found that this is sufficient to reverse DNA methylation changes that occur upon aging in the pancreas, liver, spleen, and blood. Similarly, we observed reversion of transcriptional changes, especially regarding biological processes known to change during aging. Finally, some serum metabolites and biomarkers altered with aging were also restored to young levels upon transient reprogramming. These observations indicate that a single period of OSKM expression can drive epigenetic, transcriptomic, and metabolomic changes toward a younger configuration in multiple tissues and in the serum.

An integrated multiomic and quantitative label-free microscopy-based approach to study pro-fibrotic signalling in ex vivo human precision-cut lung slices

Fibrosis can affect any organ, resulting in the loss of tissue architecture and function with often life-threatening consequences. Pathologically, fibrosis is characterised by the expansion of connective tissue due to excessive deposition of extracellular matrix (ECM) proteins, including the fibrillar forms of collagen. A significant limitation for discovering cures for fibrosis is the availability of suitable human models and techniques to quantify mature fibrillar collagen deposition as close as possible to human physiological conditions.

Here we have extensively characterised an ex vivo cultured human lung tissue-derived, precision-cut lung slices (hPCLS) model using label-free second harmonic generation (SHG) light microscopy to quantify fibrillar collagen deposition and mass spectrometry-based techniques to obtain a proteomic and metabolomic fingerprint of hPCLS in ex vivo culture.

We demonstrate that hPCLS are viable and metabolically active, with mesenchymal, epithelial, endothelial and immune cell types surviving for at least 2 weeks in ex vivo culture. Analysis of hPCLS-conditioned supernatants showed a strong induction of pulmonary fibrosis-related ECM proteins upon transforming growth factor-β1 (TGF-β1) stimulation. This upregulation of ECM proteins was not translated into an increased deposition of fibrillar collagen. In support of this observation, we revealed the presence of a pro-ECM degradation activity in our ex vivo cultures of hPCLS, inhibition of which by a metalloproteinase inhibitor resulted in increased collagen deposition in response to TGF-β1 stimulation.

Together the data show that an integrated approach of measuring soluble pro-fibrotic markers alongside quantitative SHG-based analysis of fibrillar collagen is a valuable tool for studying pro-fibrotic signalling and testing anti-fibrotic agents.

Multiomic and label-free imaging-based characterisation of ex vivo cultured human precision-cut lung slices (hPCLS) reveals that MMP signalling is a rate-limiting factor necessary for deposition of fibrillar collagen in ECM of hPCLShttps://bit.ly/3rcUa0e

Vinpocetine attenuates thioacetamide-induced liver fibrosis in rats

Liver fibrosis is associated with increased mortality and morbidity. However, there is not effective treatment so far. Vinpocetine (Vinpo) is a synthetic derivative of vinca alkaloid vincamine. Limited previous reports have shown some beneficial effects of Vinpo in different organ fibrosis, but the ability of Vinpo to inhibit liver fibrosis induced by thioacetamide (TAA) has not been reported, that is why we investigate the potential ability of this vinca alkaloid derivative to attenuate liver fibrosis. Hepatic fibrosis was induced in male Sprague Dawley rats by TAA (200 mg/kg; ip; 3 times/week) for 6 weeks. Daily treatments with Vinpo (10-20 mg/kg/day; orally) ameliorated TAA-induced hepatic oxidative stress and histopathological damage as indicated by a decrease in liver injury markers, LDH, hepatic MDA, and NOx levels, as well as increase anti-oxidative parameters. Besides, the anti-fibrotic efficacy of Vinpo was confirmed by decreasing hydroxyproline, and α-SMA. Also, the anti-inflammatory effect of Vinpo was explored by decreasing IL-6 and TNF-α levels. Our novel findings were that Vinpo decreased VEGF/Ki-67 expression in the liver confirming its effect on angiogenesis and proliferation. These findings reveal the anti-fibrotic effect of Vinpo against TAA-induced liver fibrosis in rats, and suggest the modulation of oxidative stress, inflammation, angiogenesis and proliferation as mechanistic cassette underlines this effect.