Pharmacological and clinical aspects of heme oxygenase

The mitigating effect of exogenous carbon monoxide on chronic allograft rejection and fibrosis post-lung transplantation

BACKGROUND

Small airway inflammation and fibrosis or bronchiolitis obliterans (BO) is the predominant presentation of chronic lung allograft dysfunction (CLAD) post-lung transplantation. Carbon monoxide (CO) is a critical endogenous signaling transducer with known anti-inflammatory and anti-fibrotic effects but its therapeutic potential in CLAD remains to be fully elucidated.

METHODS

Here we investigate the effect of inhaled CO in modulating chronic lung allograft rejection pathology in a murine orthotopic lung transplant model of BO (B6D2F1/J→DBA/2J). Additionally, the effects of CO on the activated phenotype of mesenchymal cells isolated from human lung transplant recipients with CLAD were studied.

RESULTS

Murine lung allografts treated with CO (250 ppm × 30 minutes twice daily from days 7 to 40 post-transplantation) demonstrated decreased immune cell infiltration, fibrosis, and airway obliteration by flow cytometry, trichrome staining, and morphometric analysis, respectively. Decreased total collagen, with levels comparable to isografts, was noted in CO-treated allografts by quantitative hydroxyproline assay. In vitro, CO (250 ppm × 16h) was effective in reversing the fibrotic phenotype of human CLAD mesenchymal cells with decreased collagen I and β-catenin expression as well as an inhibitory effect on ERK1/2 MAPK, and mTORC1/2 signaling. Sildenafil, a phosphodiesterase 5 inhibitor, partially mimicked the effects of CO on CLAD mesenchymal cells and was partially effective in decreasing collagen deposition in murine allografts, suggesting the contribution of cGMP-dependent and -independent mechanisms in mediating the effect of CO.

CONCLUSION

These results suggest a potential role for CO in alleviating allograft fibrosis and mitigating chronic rejection pathology post-lung transplant.

Determination and analysis of sex ratios in heme oxygenase 1 gene targeted mouse embryos

Heme oxygenase 1 or Hmox1 enzyme is involved in catalyzing the first and rate-limiting step in heme breakdown reactions. Many studies have reported a partial lethality of Hmox1 knockout mice obtained from heterozygous breeding pairs. Similar results were obtained in our transgenic mice colony and a sex specific bias was observed in the favor of males in the adult mice. Hmox1 independent factors which could have caused this bias were initially analyzed and it was found that those factors were not a reason behind this anomaly. Certain studies involving gene knockout hinted toward a prenatal or neonatal lethality of female knockout mice embryos or pups, respectively. In order to check if this bias was occurring in embryonic stages, that is, either if mutant female embryos were dying or if heterozygous mothers were not carrying embryos to term, we analyzed the sex-ratios in mid- and late-gestational ages (9.5-13.5 dpc and 14.5-18.5 dpc, respectively). Our results did not indicate any significant difference in the sex ratios in embryonic stages; hence, it was concluded that females are not dying in embryonic stages. It can be speculated that these deaths were probably occurring at neonatal age. More studies are required to confirm that the lack of Hmox1 gene products is the sole reason for this female lethality.

Cutting edge concepts: Does bilirubin enhance exercise performance?

Exercise performance is dependent on many factors, such as muscular strength and endurance, cardiovascular capacity, liver health, and metabolic flexibility. Recent studies show that plasma levels of bilirubin, which has classically been viewed as a liver dysfunction biomarker, are elevated by exercise training and that elite athletes may have significantly higher levels. Other studies have shown higher plasma bilirubin levels in athletes and active individuals compared to general, sedentary populations. The reason for these adaptions is unclear, but it could be related to bilirubin's antioxidant properties in response to a large number of reactive oxygen species (ROS) that originates from mitochondria during exercise. However, the mechanisms of these are unknown. Current research has re-defined bilirubin as a metabolic hormone that interacts with nuclear receptors to drive gene transcription, which reduces body weight. Bilirubin has been shown to reduce adiposity and improve the cardiovascular system, which might be related to the adaption of bilirubin increasing during exercise. No studies have directly tested if elevating bilirubin levels can influence athletic performance. However, based on the mechanisms proposed in the present review, this seems plausible and an area to consider for future studies. Here, we discuss the importance of bilirubin and exercise and how the combination might improve metabolic health outcomes and possibly athletic performance.

Sex difference in the associations among liver function parameters with incident diabetes mellitus in a large Taiwanese population follow-up study

Background

The prevalence of diabetes mellitus (DM) in Taiwan between 2017 and 2020 was 11.05%, which is higher than the global prevalence (10.5%). Previous studies have shown that patients with DM have higher liver enzyme levels than those without DM. However, it is unclear whether there are sex differences in the association between incident DM and liver function. Therefore, the aim of this longitudinal study was to investigate this issue in a large Taiwanese cohort.

Methods

We identified 27,026 participants from the Taiwan Biobank, and excluded those with baseline DM (n = 2,637), and those without follow-up data on DM, serum fasting glucose or glycosylated hemoglobin A1c (n = 43). The remaining 24,346 participants (male: 8,334; female: 16,012; mean age 50.5 ± 10.4 years) were enrolled and followed for a median of 4 years.

Results

Of the enrolled participants, 1,109 (4.6%) had incident DM and 23,237 (95.4%) did not. Multivariable analysis showed that high levels of glutamic-oxaloacetic transaminase (AST) (p < 0.001), glutamic-pyruvic transaminase (ALT) (p < 0.001), albumin (p = 0.003), α-fetoprotein (p = 0.019), and gamma-glutamyl transpeptidase (GGT) (p = 0.001) were significantly associated with incident DM in the male participants. In comparison, high levels of AST (p = 0.010), ALT (p < 0.001), albumin (p = 0.001) and GGT (p < 0.001), and low total bilirubin (p = 0.001) were significantly associated with incident DM in the female participants. There were significant interactions between total bilirubin and sex (p = 0.031), and GGT and sex (p = 0.011) on incident DM.

Conclusion

In conclusion, liver function parameters were significantly associated with incident DM. Further, there were differences in the associations between the male and female participants.

The dual role and mutual dependence of heme/HO-1/Bach1 axis in the carcinogenic and anti-carcinogenic intersection

INTRODUCTION

In physiological concentrations, heme is nontoxic to the cell and is essential for cell survival and proliferation. Increasing intracellular heme concentrations beyond normal levels, however, will lead to carcinogenesis and facilitate the survival of tumor cells. Simultaneously, heme in an abnormally high quantity is also a potent inducer of tumor cell death, contributing to its ability to generate oxidative stress on the cells by boosting oxidative phosphorylation and suppressing tumors through ferroptosis. During tumorigenesis and progression, therefore, heme works as a double-edged sword. Heme oxygenase 1 (HO-1) is the rate-limiting enzyme in heme catabolism, which converts heme into physiologically active catabolites of carbon monoxide (CO), biliverdin, and ferrous iron (Fe²⁺). HO-1 maintains redox equilibrium in healthy cells and functions as a carcinogenesis inhibitor. It is widely recognized that HO-1 is involved in the adaptive response to cellular stress and the anti-inflammation effect. Notably, its expression level in cancer cells corresponds with tumor growth, aggressiveness, metastasis, and angiogenesis. Besides, heme-binding transcription factor BTB and CNC homology 1 (Bach1) play a critical regulatory role in heme homeostasis, oxidative stress and senescence, cell cycle, angiogenesis, immune cell differentiation, and autoimmune disorders. Moreover, it was found that Bach1 influences cancer cells' metabolism and metastatic capacity. Bach1 controls heme level by adjusting HO-1 expression, establishing a negative feedback loop.

MATERIALS AND METHODS

Herein, the authors review recent studies on heme, HO-1, and Bach1 in cancer. Specifically, they cover the following areas: (1) the carcinogenic and anticarcinogenic aspects of heme; (2) the carcinogenic and anticarcinogenic aspects of HO-1; (3) the carcinogenic and anticarcinogenic aspects of Bach1; (4) the interactions of the heme/HO-1/Bach1 axis involved in tumor progression.

CONCLUSION

This review summarized the literature about the dual role of the heme/HO-1/Bach1 axis and their mutual dependence in the carcinogenesis and anti-carcinogenesis intersection.

Heme-heme oxygenase-2 reduces the atherosclerosis by preventing inflammation

Objective

Heme oxygenase (HO) has been shown to have important antioxidant and anti-inflammatory properties, resulting in a vascular antitherogenic effect. This study was undertaken to evaluate the role of HO-2 in atherosclerosis.

Method and results

The expression levels of HO-2 were evaluated in M1 and M2 bone marrow macrophage induced by LPS and IL4. The expression of HO-2 was significantly higher in M2 macrophage than in M1 macrophage. Western diet (WD) caused a significant increase in HO-2 expression in ApoE^-/- mice. The adeno-associated viral (AAV) vectors expressing HO-2 was constructed, and the mice were received saline (ApoE^-/-), AAV (ApoE^-/-), AAV-HO-2 (ApoE^-/-) on WD at 12 weeks and their plasma lipids, inflammatory cytokines, atherosclerosis were evaluated for 16 weeks. The results showed AAV-HO-2 was robust, with a significant decrease in the en face aortas, lipids levels, inflammatory cytokines and M1 macrophage content in AAV-HO-2 ApoE^-/- compared to control AAV-ApoE^-/-.

Conclusion

HO-2 expression in macrophages plays an important role of the antiatherogenic effect, decreasing the inflammatory component of atherosclerotic lesions. These results suggest that HO-2 may be a novel therapeutic target for cardiovascular diseases.

The Inhibitory Effect of Phycocyanin Peptide on Pulmonary Fibrosis In Vitro

Phycocyanin is an excellent antioxidant with anti-inflammatory effects on which recent studies are growing; however, its specific target remains unclear. Linear tetrapyrrole compounds such as bilirubin have been shown to lead to the induction of heme oxygenase 1 expression in vivo, thus achieving antioxidant and anti-inflammatory effects. Phycocyanin is bound internally with linear tetrapyrrole phycocyanobilin in a similar structure to bilirubin. We speculate that there is probably a way of inducing the expression of heme oxygenase 1, with which tissue oxidative stress and inflammation can be inhibited, thus inhibiting pulmonary fibrosis caused by oxidative damage and inflammation of lung. By optimizing the enzymatic hydrolysis process, phycocyanobilin-bound phycocyanin peptide were obtained, and its in vitro antioxidant, anti-inflammatory, and anti-pulmonary fibrosis activities were investigated. The results show that the phycocyanobilin peptide was able to alleviate oxidative and inflammatory damage in cells through the Keap1-Nrf2-HO-1 pathway, which in turn relieved pulmonary fibrosis symptoms.

Gap junction intercellular communication mediates cadmium-induced apoptosis in hepatocytes via the Fas/FasL pathway

As a common environmental pollutant, cadmium (Cd) causes damage to many organs of the body. Gap junction intercellular communication (GJIC) represents one of the most important routes of rapid signaling between cells. However, the mechanisms underlying GJIC's role in hepatotoxicity induced by Cd remain unknown. We established a Cd poisoning model in vitro by co-culturing Cd-exposed and unexposed hepatocytes and found that 18β-glycyrrhetinic acid (GA), a GJIC inhibitor, can effectively reduce the apoptosis rate of healthy cells co-cultured with apoptotic cells treated with Cd. We also found that anti-FasL antibody had the same effect. However, in mono-cultured cells, GA treatment in combination with Cd was found to aggravate the damage induced by Cd exposure, increase the level of oxidative stress and protein expression of HO-1, decrease the mitochondrial membrane potential, incur more serious morphological damage to mitochondria than Cd treatment alone. Moreover, compared with Cd-only exposure, GA and Cd co-treatment further increased the expression levels of the apoptosis-related proteins Fas, FasL, FADD and the ratio of Bax/Bcl-2, inhibited the protein expression of ASK1 and Daxx. We also found that the protein expression of Daxx in siFADD + Cd hepatocytes was significantly higher than in Cd-treated cells. Thus, our study suggests that gap junction inhibition may play a dual role in Cd-induced cell damage by inhibiting the transmission of death signals from damaged cells to healthy cells but also aggravating the transmission of death signals between damaged cells, and that the Fas/FasL-mediated death receptor pathway may play an important role in this process.

Role of Nrf2 and HO-1 in intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is a common age-related disease with clinical manifestations of lumbar and leg pain and limited mobility. The pathogenesis of IDD is mainly mediated by the death of intervertebral disc (IVD) cells and the imbalance of extracellular matrix (ECM) synthesis and degradation. Oxidative stress and inflammatory reactions are the important factors causing this pathological change. Therefore, the regulation of reactive oxygen species and production of inflammatory factors may be an effective strategy to delay the progression of IDD. In recent years, nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream regulated protein heme oxygenase-1 (HO-1) have received special attention due to their antioxidant, anti-inflammatory and anti-apoptotic protective effects. Recent studies have elucidated the important role of these two proteins in the treatment of IDD disease. However, Nrf2 and HO-1 have not been systematically reported in IDD-related diseases. Therefore, this review describes the biological characteristics of Nrf2 and HO-1, the relationship between Nrf2- and HO-1-regulated oxidative stress and the inflammatory response and IDD, and the progress in research on some extracts targeting Nrf2 and HO-1 to improve IDD. Understanding the role and mechanism of Nrf2 and HO-1 in IDD may provide novel ideas for the clinical treatment and development of Nrf2- and HO-1-targeted drugs.

Heme Oxygenase-1 as Therapeutic Target for Diabetic Foot Ulcers

A diabetic foot ulcer (DFU) is one of the major complications of diabetes. Wound healing under diabetic conditions is often impaired. This is in part due to the excessive oxidative stress, prolonged inflammation, immune cell dysfunction, delayed re-epithelialization, and decreased angiogenesis present at the wound site. As a result of these multifactorial impaired healing pathways, it has been difficult to develop effective therapeutic strategies for DFU. Heme oxygenase-1 (HO-1) is the rate-limiting enzyme in heme degradation generating carbon monoxide (CO), biliverdin (BV) which is converted into bilirubin (BR), and iron. HO-1 is a potent antioxidant. It can act as an anti-inflammatory, proliferative, angiogenic and cytoprotective enzyme. Due to its biological functions, HO-1 plays a very important role in wound healing, in part mediated through the biologically active end products generated by its enzymatic activity, particularly CO, BV, and BR. Therapeutic strategies involving the activation of HO-1, or the topical application of its biologically active end products are important in diabetic wound healing. Therefore, HO-1 is an attractive therapeutic target for DFU treatment. This review will provide an overview and discussion of the importance of HO-1 as a therapeutic target for diabetic wound healing.

Differential Effects of Arsenic in Drinking Water on Mouse Hepatic and Intestinal Heme Oxygenase-1 Expression

Arsenic exposure has been associated with the risks of various diseases, including cancers and metabolic diseases. The aim of this study was to examine the effects of arsenic exposure via drinking water on the expression of heme oxygenase-1 (HO-1), a major responsive gene to arsenic-induced oxidative stress, in mouse intestinal epithelial cells which is the first site of exposure for ingested arsenic, and the liver, a known target of arsenic toxicity. The expression of HO-1 was determined at mRNA, protein, or enzymic activity levels in mice exposed to sodium arsenite through drinking water, at various doses (0, 2.5, 10, 25, 100 ppm), and for various time periods (1, 3, 7, or 28 days). HO-1 was significantly induced in the intestine, but not liver, at arsenic doses of 25 ppm or lower. The intestinal HO-1 induction was seen in both males and females, plateaued within 1-3 days of exposure, and was accompanied by increases in microsomal HO activity. In mice exposed to 25-ppm of arsenite for 7 days, total arsenic and As(III) levels in intestinal epithelial cells were significantly higher than in the liver. These findings identify intestinal epithelial cells as likely preferential targets for arsenic toxicity and support further studies on the functional consequences of intestinal HO-1 induction.

Molecular, Pathological, Clinical, and Therapeutic Aspects of Perihematomal Edema in Different Stages of Intracerebral Hemorrhage

Acute intracerebral hemorrhage (ICH) is a devastating type of stroke worldwide. Neuronal destruction involved in the brain damage process caused by ICH includes a primary injury formed by the mass effect of the hematoma and a secondary injury induced by the degradation products of a blood clot. Additionally, factors in the coagulation cascade and complement activation process also contribute to secondary brain injury by promoting the disruption of the blood-brain barrier and neuronal cell degeneration by enhancing the inflammatory response, oxidative stress, etc. Although treatment options for direct damage are limited, various strategies have been proposed to treat secondary injury post-ICH. Perihematomal edema (PHE) is a potential surrogate marker for secondary injury and may contribute to poor outcomes after ICH. Therefore, it is essential to investigate the underlying pathological mechanism, evolution, and potential therapeutic strategies to treat PHE. Here, we review the pathophysiology and imaging characteristics of PHE at different stages after acute ICH. As illustrated in preclinical and clinical studies, we discussed the merits and limitations of varying PHE quantification protocols, including absolute PHE volume, relative PHE volume, and extension distance calculated with images and other techniques. Importantly, this review summarizes the factors that affect PHE by focusing on traditional variables, the cerebral venous drainage system, and the brain lymphatic drainage system. Finally, to facilitate translational research, we analyze why the relationship between PHE and the functional outcome of ICH is currently controversial. We also emphasize promising therapeutic approaches that modulate multiple targets to alleviate PHE and promote neurologic recovery after acute ICH.

Controlled therapeutic delivery of CO from carbon monoxide-releasing molecules (CORMs)

Carbon monoxide (CO) has been regarded as a "silent killer" for its toxicity toward biological systems. However, a low concentration of endogenously produced CO has shown a number of therapeutic benefits such as anti-inflammatory, anti-proliferative, anti-apoptosis, and cytoprotective activities. Carbon monoxide-releasing molecules (CORMs) have been developed as alternatives to direct CO inhalation, which requires a specialized setting for strict dose control. CORMs are efficient CO donors, with central transition metals (such as ruthenium, iron, cobalt, and manganese) surrounded by CO as a ligand. CORMs can stably store and subsequently release their CO payload in the presence of certain triggers including solvent, light, temperature, and ligand substitution. However, CORMs require appropriate delivery strategies to improve short CO release half-life and target specificity. Herein, we highlighted the therapeutic potential of inhalation and CORMs-delivered CO. The applications of conjugate and nanocarrier systems for controlling CO release and improving therapeutic efficacy of CORMs are also described in detail. The review concludes with some of the hurdles that limit clinical translation of CORMs. Keeping in mind the tremendous potential and growing interest in CORMs, this review would be helpful for designing controlled CO release systems for clinical applications.

Apigenin attenuates molecular, biochemical, and histopathological changes associated with renal impairments induced by gentamicin exposure in rats

Gentamicin (GM) is an aminoglycoside antibiotic used to treat bacterial infections. However, its application is accompanied by renal impairments. Apigenin is a flavonoid found in many edible plants with potent therapeutic values. This study was designed to elucidate the therapeutic effects of apigenin on GM-induced nephrotoxicity. Animals were injected orally with three different doses of apigenin (5 mg kg-1 day-1, 10 mg kg-1 day-1, and 20 mg kg-1 day-1). Apigenin administration abolished the alterations in the kidney index and serum levels of kidney-specific functions markers, namely blood urea nitrogen and creatinine, and KIM-1, NGAL, and cystatin C following GM exposure. Additionally, apigenin increased levels of enzymatic (glutathione reductase, glutathione peroxidase, superoxide dismutase, and catalase) and non-enzymatic antioxidant proteins (reduced glutathione) and decreased levels of lipid peroxide, nitric oxide, and downregulated nitric oxide synthase-2 in the kidney tissue following GM administration. At the molecular scope, apigenin administration was found to upregulate the mRNA expression of Nfe2l2 and Hmox1 in the kidney tissue. Moreover, apigenin administration suppressed renal inflammation and apoptosis by decreasing levels of interleukin-1β, tumor necrosis factor-alpha, nuclear factor kappa-B, Bax, and caspase-3, while increasing B-cell lymphoma-2 compared with those in GM-administered group. The recorded data suggests that apigenin treatment could be used to alleviate renal impairments associated with GM administration.

Hemin Ameliorates the Inflammatory Activity in the Inflammatory Bowel Disease: A Non-Clinical Study in Rodents

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract. Currently, there is no cure, and pharmacological treatment aims to induce and maintain remission in patients, so it is essential to investigate new possible treatments. Hemin is a heme-oxygenase inducer which can confer anti-inflammatory, cytoprotective, and antiapoptotic effects; therefore, it can be considered an asset for different gastrointestinal pathologies, namely for IBD.

AIM

This experiment aims to evaluate the efficacy and safety of hemin, in a chronic 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis model in rodents.

METHODS

The induction of chronic colitis consisted of five weekly intrarectal administrations of 1% TNBS. Then, the mice were treated daily with 5 mg/kg/day or 10 mg/kg/day of hemin, through intraperitoneal injections, for 14 days.

RESULTS

Hemin demonstrated an anti-inflammatory effect through the reduction in tumor necrosis factor (TNF)-α levels, fecal calprotectin, and fecal hemoglobin. It was also found to be safe in terms of extraintestinal manifestations, since hemin did not promote renal and/or hepatic changes.

CONCLUSIONS

Hemin could become an interesting tool for new possible pharmacological approaches in the management of IBD.

α‑lipoic acid inhibits cerulein/resistin‑induced expression of interleukin‑6 by activating peroxisome proliferator‑activated receptor‑γ in pancreatic acinar cells

Cerulein‑induced pancreatitis resembles human acute pancreatitis in terms of pathological events, such as enzymatic activation and inflammatory cell infiltration in the pancreas. Cerulein is a cholecystokinin analog that increases levels of reactive oxygen species (ROS) and interleukin‑6 (IL‑6) expression level in pancreatic acinar cells. Serum levels of resistin, which is secreted from adipocytes, are reportedly higher in patients with acute pancreatitis than in healthy individuals. Previously, it was shown that the adipokine resistin can aggravate the cerulein‑induced increase in ROS levels and IL‑6 expression level in pancreatic acinar cells. Peroxisome proliferator‑activated receptor‑gamma (PPAR‑γ) is a key regulator of the transcription and expression of antioxidant enzymes, including heme oxygenase 1 (HO‑1) and catalase. α‑lipoic acid, a naturally occurring dithiol antioxidant, can prevent cerulein‑induced pancreatic damage in rats. In the present study, it was aimed to investigate whether α‑lipoic acid can attenuate the cerulein/resistin‑induced increase in IL‑6 expression and ROS levels via PPAR‑γ activation in pancreatic acinar AR42J cells. The anti‑inflammatory mechanism of α‑lipoic acid was determined using reverse transcription‑quantitative PCR, western blot analysis, enzyme‑linked immunosorbent assay, immunofluorescence staining and fluorometry. Treatment with cerulein and resistin increased ROS levels and IL‑6 expression level, which were inhibited by α‑lipoic acid in pancreatic acinar cells. α‑lipoic acid increased the nuclear translocation and expression level of PPAR‑γ and the expression levels of its target genes: HO‑1 and catalase. The PPAR‑γ antagonist GW9662 and HO‑1 inhibitor zinc protoporphyrin reversed the inhibitory effect of α‑lipoic acid on cerulein/resistin‑induced increase in ROS and IL‑6 levels. In conclusion, α‑lipoic acid inhibits the cerulein/resistin‑induced increase in ROS production and IL‑6 expression levels by activating PPAR‑γ and inducing the expression of HO‑1 and catalase in pancreatic acinar cells.

Carboxyhemoglobin (CO-Hb) Correlates with Hemolysis and Hospital Mortality in Extracorporeal Membrane Oxygenation: A Retrospective Registry

Background: Patients supported with extracorporeal membrane oxygenation (ECMO) may develop elevated carboxyhemoglobin (CO-Hb), a finding described in the context of hemolysis. Clinical relevance of elevated CO-Hb in ECMO is unclear. We therefore investigated the prognostic relevance of CO-Hb during ECMO support. Methods: Data derives from a retrospective single-center registry study. All ECMO patients in a medical ICU from October 2010 through December 2019 were considered. Peak arterial CO-Hb value during ECMO support and median CO-Hb values determined by point-of-care testing for distinct time intervals were determined. Groups were divided by CO-Hb (<2% or ≥2%). The primary endpoint was hospital survival. Results: A total of 729 patients with 59,694 CO-Hb values met the inclusion criteria. Median age (IQR) was 59 (48−68) years, 221/729 (30.3%) were female, and 278/729 (38.1%) survived until hospital discharge. Initial ECMO configuration was veno-arterial in 431/729 (59.1%) patients and veno-venous in 298/729 (40.9%) patients. Markers for hemolysis (lactate dehydrogenase, bilirubin, hemolysis index, and haptoglobin) all correlated significantly with higher CO-Hb (p < 0.001, respectively). Hospital survival was significantly higher in patients with CO-Hb < 2% compared to CO-Hb ≥ 2%, evaluating time periods 24−48 h (48.6% vs. 35.2%, p = 0.003), 48−72 h (51.5% vs. 36.8%, p = 0.003), or >72 h (56.9% vs. 31.1%, p < 0.001) after ECMO cannulation. Peak CO-Hb was independently associated with lower hospital survival after adjustment for confounders. Conclusions: In ECMO, CO-Hb correlates with hemolysis and hospital survival. If high CO-Hb measured should trigger a therapeutic intervention in order to reduce hemolysis has to be investigated in prospective trials.

<em>Lactobacillus plantarum</em> Lp2 improved LPS-induced liver injury through the TLR-4/MAPK/NFκB and Nrf2-HO-1/CYP2E1 pathways in mice

Background: Inflammatory liver diseases present a significant public health problem. Probiotics are a kind of living microorganisms, which can improve the balance of host intestinal flora, promote the proliferation of intestinal beneficial bacteria, inhibit the growth of harmful bacteria, improve immunity, reduce blood lipids and so on. Probiotics in fermented foods have attracted considerable attention lately as treatment options for liver injury. Objective: The aim of this study was selected probiotic strain with well probiotic properties from naturally fermented foods and investigated the underlying mechanisms of screened probiotic strain on lipopolysaccharide (LPS)-induced liver injury, which provided the theoretical foundation for the development of probiotics functional food. Design: The probiotic characteristics of Lactobacillus plantarum Lp2 isolated from Chinese traditional fermented food were evaluated. Male KM mice were randomly assigned into three groups: normal chow (Control), LPS and LPS with L. plantarum Lp2. L. plantarum Lp2 were orally administered for 4 weeks before exposure to LPS. The liver injury of LPS-induced mice was observed through the evaluation of biochemical indexes, protein expression level and liver histopathology. Results and discussions: After treatment for 4 weeks, L. plantarum Lp2 administration significantly reduced the LPS-induced liver coefficient and the levels of serum or liver aspartate transaminase (AST), alanine aminotransferase (ALT), tumor necrosis factor α (TNF-α), interleukin-6 (IL-6) and LPS, as well as decreasing the histological alterations and protein compared with the LPS group. Western-blotting results showed that L. plantarum Lp2 activated the signal pathway of TLR4/MAPK/NFκB/NRF2-HO-1/CYP2E1/Caspase-3 and regulated the expression of related proteins. Conclusions: In summary, L. plantarum Lp2 suppressed the LPS-induced activation of inflammatory pathways, oxidative injury and apoptosis has the potential to be used to improve liver injury.

Angiotensin 1-7 mitigates rhabdomyolysis induced renal injury in rats via modulation of TLR-4/NF-kB/iNOS and Nrf-2/heme‑oxygenase-1 signaling pathways

AIMS

Rhabdomyolysis (RM) is a critical condition with a high mortality rate, but effective management is still deficient. Till date, there are no studies that have addressed the effect of angiotensin 1-7 in this condition, hence, the rationale of this study was to evaluate the potential protective effect of Angiotensin 1-7 (Ang1-7), on rhabdomyolysis (RM) induced kidney injury in rats and detecting the underlying mechanistic insights.

MAIN METHODS

Forty adult male albino rats were divided into groups; the control group, RM group, RM+Ang1-7 group, and RM+Ang1-7+ A779 group. Sera and urine samples were collected for analysis of renal and muscle injury markers. Kidney tissues were taken for estimation of oxidative, inflammatory, and apoptotic markers as well as angiotensin-II (Ang II) and Ang1-7. Renal histology and expression of inducible nitric oxide synthase-1 (iNOS), real-time PCR for angiotensin-converting enzyme-2 (ACE-2), nuclear erythroid factor-2 (Nrf-2), Toll like receptor 4 (TLR-4) and NF-kB in kidney tissues were also measured.

KEY FINDINGS

Induction of RM caused renal oxidative stress injury, inflammation, apoptosis and marked deterioration in kidney functions as well as reduction of Ang1-7 and raised Angiotensin-II level in kidney tissues. Administration of Ang1-7 to the RM group reversed all the affected parameters which were blocked by A779 administration (Mas receptor blocker).

SIGNIFICANCE

We concluded that Ang1-7 could be a potential therapeutic agent that could mitigate RM-induced renal injury. The underlying mechanisms may involve Stimulation of the ACE-2/Ang1-7/MasR axis and modulation of TLR-4/NF-kB/iNOS and Nrf-2/heme‑oxygenase -1 pathways.

Preliminary studies of an imidazole-based alcohol derivative for imaging of Heme oxygenase 1

Heme oxygenase-1 (HO-1) has been involved in the pathogenesis of Alzheimer's disease (AD), thus constituting a promising target for AD drug development. Positron emission tomography (PET) is a fully translational imaging technology, which will help us understand the role of HO-1 in the progression of AD, facilitating to validate promising HO-1 inhibitors in clinical trials. To our knowledge, there is no report on PET imaging probe targeting HO-1 in animals and humans. We report herein the synthesis and characterization of a ¹¹C-labeled imidazole-based alcohol derivative ([¹¹C]QC-33) for imaging of HO-1 in the brain. The desired product [¹¹C]QC-33 was afforded with a radiochemical yield of 16 ± 9% (n = 3, decay corrected). The radiochemical purity was greater than 99%, and the molar radioactivity was greater than 185 GBq/μmol. In vitro autoradiography studies indicated specific binding of [¹¹C]QC-33 in the HO-1 rich regions, showing 75%, 75%, and 69% radioactivity binding reductions in cerebellum, brain stem, and midbrain, respectively. PET/CT scanning in C57BL/6 mice showed low brain uptake and poor blood-brain barrier (BBB) penetration of [¹¹C]QC-33. These results suggested that [¹¹C]QC-33 can serve as a lead compound to advance the development of next generation PET tracer with the potential to monitor HO-1 in AD progression.

Nanoformulation of a carbon monoxide releasing molecule protects against cyclosporin A-induced nephrotoxicity and renal fibrosis via the suppression of the NLRP3 inflammasome mediated TGF-β/Smad pathway

Cyclosporin A (CsA) induced nephrotoxicity i.e., renal fibrosis is a critical clinical problem in renal transplant patients, in which chronic inflammatory response is the major cause. Previously, we developed a nano-drug delivery system for carbon monoxide (CO), a multi-functional gaseous molecule with a potent anti-inflammatory effect, i.e., SMA/CORM2, which showed therapeutic potential in several inflammatory disease models. Accordingly, in this study, we explored the potential and usefulness of SMA/CORM2 on CsA induced renal fibrosis. When mice were exposed to CsA for 4 weeks, severe injuries in the kidney as revealed by decreased kidney function and histological examination, and activation of NLRP3 inflammasome, as well as renal fibrosis along with the upregulation of transforming growth factor β (TGFβ)/Smad signaling molecule were observed, whereas SMA/CORM2 (1 mg/kg) treatment remarkably ameliorated the inflammatory injury and fibrosis in the kidney. CO is the major effector molecule of SMA/CORM2 which significantly suppressed the activation of NLRP3 inflammasome, and induced the downregulation of TGFβ/Smad signaling. Inhibition of NLRP3 inflammasome by its inhibitor MCC950 also similarly decreased TGFβ/Smad expression and subsequently improved kidney injury and renal fibrosis, suggesting SMA/CORM2 induced suppression of TGFβ/Smad signaling and renal signaling via an NLRP3 inflammasome-dependent pathway. Compared to native CORM2, SMA/CORM2 exhibited better therapeutic/preventive effects owing to its superior water-solubility and bioavailability. These findings strongly indicated the applicability of SMA/CORM2 as an enhanced permeability and retention (EPR) effect-based nanomedicine for CsA induced renal fibrosis as well as other inflammatory diseases. STATEMENT OF SIGNIFICANCE: Carbon monoxide (CO) is an important gaseous signaling molecule that plays a crucial role in the maintenance of homeostasis. Because of its versatile functions, it exhibits the potential as the target molecule for many diseases, including inflammatory diseases and cancer. The development of stable and disease-targeted delivery systems of CO is thus of interest and importance. Previously we developed a nano micellar CO donor SMA/CORM2 which shows superior bioavailability and therapeutic potential in many inflammatory disease models. We reported here, SMA/CORM2, through controlled release of CO, greatly ameliorated CsA-induced renal fibrosis via suppressing the NLRP3 inflammasome mediated TGF-β/Smad pathway. These findings suggest a new anti-inflammatory mechanism of CO, which also provides a new approach for controlling CsA-induced nephrotoxicity.

Heme oxygenase-1 induction by gallic acid-g-chitosan is an important event in modulating adipocyte differentiation

Obesity, one of the common worldwide chronic health diseases co-relates with adipogenesis. Adipogenesis is a complex biological action of the emergence of mature adipocytes from the differentiation of pre-adipocytes and the disfunction of this process leads to the development of metabolic issues in obesity. Recently, much attention has been paid to utilizing natural compounds to discover their biological activities. This study focused on investigating the probable anti-adipogenic effects of gallic acid-g-chitosan (GAC) and plain chitosan (PC) through regulating the heme oxygenase-1 (HO-1)/Nrf2 pathway on mesenchymal stem cells. Gallic acid is grafted onto the PC backbone to improve its specific physical and biological properties. GAC showed promising anti-adipogenic effects by enhancing HO-1 expression and lipolysis and as well as suppressing lipid accumulation, reactive oxygen species, and pro-inflammatory cytokines production, transcription factor expression compared to the PC treatment. On the contrary, zinc protoporphyrin ІX (ZnPP), a HO-1 inhibitor reversed these effects of GAC on adipogenesis. Taken all together, this study revealed that grafting GA onto the chitosan improved potential anti-adipogenic activity by induction of the HO-1/Nrf2 pathway on mesenchymal stem cells (MSCs). PRACTICAL APPLICATIONS: GAC is a well-known copolymer with versatile bioactivities such as antimicrobial, antioxidant, and anti-diabetic activity. However, the anti-adipogenic effect of GAC has not been explored in MSCs. This study demonstrated that GAC inhibited adipocyte differentiation in MSCs through HO-1 activation. These findings suggest that GAC can be applied practically from different perspectives. GAC can be applied in the pharmacological industry to the development of anti-obesity drugs, medicinal perspectives for the treatment of obesity and obesity-related diseases, and in the food industry as a functional food to promote health and decrease the risk of diseases.

The Efficacy and Tolerability of Turmeric and Salicylic Acid in Psoriasis Treatment

Introduction

Patients and Methods

Results

Conclusion

The Biological Activity of 3-O-Acetyl-11-keto-β-Boswellic Acid in Nervous System Diseases

Frankincense is a hard gelatinous resin exuded by Boswellia serrata. It contains a complex array of components, of which acetyl-11-keto-beta-boswellic acid (AKBA), a pentacyclic triterpenoid of the resin class, is the main active component. AKBA has a variety of physiological actions, including anti-infection, anti-tumor, and antioxidant effects. The use of AKBA for the treatment of mental diseases has been documented as early as ancient Greece. Recent studies have found that AKBA has anti-aging and other neurological effects, suggesting its potential for the treatment of neurological diseases. This review focuses on nervous system-related diseases, summarizes the functions and mechanisms of AKBA in promoting nerve repair and regeneration after injury, protecting against ischemic brain injury and aging, inhibiting neuroinflammation, ameliorating memory deficits, and alleviating neurotoxicity, as well as having anti-glioma effects and relieving brain edema. The mechanisms by which AKBA functions in different diseases and the relationships between dosage and biological effects are discussed in depth with the aim of increasing understanding of AKBA and guiding its use for the treatment of nervous system diseases.

Macrophages Protect Endometriotic Cells Against Oxidative Damage Through a Cross-Talk Mechanism

This aim of this study was to investigate whether macrophages protect endometriotic cells from oxidative injury and to elucidate the underlying mechanisms of any protection. Endometriotic cells cultured with or without differentiated macrophages (dTHP-1 cells) were treated with hydrogen peroxide (H₂O₂) or methemoglobin, a major component of hemoglobin species in endometriotic cyst fluid. Co-culture experiments, microarray analysis, screening and validation of differentially expressed genes (DEGs), cell proliferation and viability assays, and experiments using a specific inhibitor were conducted to investigate the functional cross-talk between endometriotic cells and macrophages. Microarray analysis revealed that endometriotic cells co-cultured with dTHP-1 differentially express several genes compared with monoculture. Quantitative enzyme-linked immunosorbent assay (ELISA) and Western blotting analysis identified TGF-β1 as a promising candidate gene expressed in endometriotic cells co-cultured with dTHP-1 cells. TGF-β1 stimulated the expression of heme oxygenase-1 (HO-1) in dTHP-1 cells. HO-1 expression was increased in dTHP-1 cells co-cultured with endometriotic cells compared with the dTHP-1 monoculture. Both H₂O₂ and methemoglobin upregulated the expression of the HO-1 protein in the dTHP-1 monoculture; moreover, co-culture with endometriotic cells further enhanced HO-1 production. The co-culture with dTHP-1 protected endometriotic cells against oxidative injury. Blockade of HO-1 abolished the protective effects of macrophages. In an oxidative stress environment, TGF-β1 produced by endometriotic cells may protect against oxidative injury through the upregulation of macrophage-derived HO-1. The cross-talk between endometriotic cells and macrophages may contribute to the progression and pathogenesis of endometriosis.

Proteome-wide analysis reveals molecular pathways affected by AgNP in a ROS-dependent manner

The use of mass spectrometry-based proteomics has been increasingly applied in nanomaterials risk assessments as it provides a proteome-wide overview of the molecular disturbances induced by its exposure. Here, we used this technique to gain detailed molecular insights into the role of ROS as an effector of AgNP toxicity, by incubating Bend3 cells with AgNP in the absence or presence of an antioxidant N-acetyl L-cystein (NAC). ROS generation is a key player in AgNP-induced toxicity, as cellular homeostasis was kept in the presence of NAC. By integrating MS/MS data with bioinformatics tools, in the absence of NAC, we were able to pinpoint precisely which biological pathways were affected by AgNP. Cells respond to AgNP-induced ROS generation by increasing their antioxidant pool, via NRF2 pathway activation. Additionally, cell proliferation-related pathways were strongly inhibited in a ROS-dependent manner. These findings reveal important aspects of the AgNP mechanism of action at the protein level.

A Journey into the Clinical Relevance of Heme Oxygenase 1 for Human Inflammatory Disease and Viral Clearance: Why Does It Matter on the COVID-19 Scene?

Heme oxygenase 1 (HO-1), the rate-limiting enzyme in heme degradation, is involved in the maintenance of cellular homeostasis, exerting a cytoprotective role by its antioxidative and anti-inflammatory functions. HO-1 and its end products, biliverdin, carbon monoxide and free iron (Fe²⁺), confer cytoprotection against inflammatory and oxidative injury. Additionally, HO-1 exerts antiviral properties against a diverse range of viral infections by interfering with replication or activating the interferon (IFN) pathway. Severe cases of coronavirus disease 2019 (COVID-19), an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are characterized by systemic hyperinflammation, which, in some cases, leads to severe or fatal symptoms as a consequence of respiratory failure, lung and heart damage, kidney failure, and nervous system complications. This review summarizes the current research on the protective role of HO-1 in inflammatory diseases and against a wide range of viral infections, positioning HO-1 as an attractive target to ameliorate clinical manifestations during COVID-19.

Therapeutic Potential of Perillaldehyde in Ameliorating Vulvovaginal Candidiasis by Reducing Vaginal Oxidative Stress and Apoptosis

Vulvovaginal candidiasis (VVC) is one of the most frequent diseases induced by Candida albicans (C. albicans) during pregnancy, which results in enormous pain to women and their partners in daily life. Perillaldehyde (PAE), a natural monoterpenoid, has significant anti-microbial, anti-inflammatory and anti-oxidation effects. Reactive oxygen species (ROS) are key factors for the host to resist the invasion of fungi. However, excess ROS can cause additional damage independent of the pathogen itself, and the mechanism of ROS in VVC has not been investigated. In this murine study, we revealed that C. albicans infection increased the expression of NADPH oxidase 2 (NOX2) and the content of malonaldehyde (MDA). C. albicans inhibited the activity of antioxidant enzymes in the vagina, including superoxide dismutase (SOD), Catalase (CAT), glutathione peroxidase (GSH-PX) and heme oxygenase (HO-1), which were returned to normal levels after treatment with PAE. Furthermore, PAE inhibited the activities of Keap1 and promoted Nrf2 transfer from cytoplasm to nucleus, which were mediated by excessive accumulation of ROS in the VVC mice. In this study, we also indicated that PAE inhibited the apoptosis of vagina cells via Caspase 9- Caspase 7-PARP pathway and prevented the release of IL-1ꞵ in VVC mice. In summary, this study revealed that the treatment of VVC in mice with PAE might be mediated by inhibition of ROS, and established the therapeutic potential of PAE as an antifungal agent for the treatment of VVC.

Analysis of Factors Affecting 5-ALA Fluorescence Intensity in Visualizing Glial Tumor Cells-Literature Review

Glial tumors are one of the most common lesions of the central nervous system. Despite the implementation of appropriate treatment, the prognosis is not successful. As shown in the literature, maximal tumor resection is a key element in improving therapeutic outcome. One of the methods to achieve it is the use of fluorescent intraoperative navigation with 5-aminolevulinic acid. Unfortunately, often the level of fluorescence emitted is not satisfactory, resulting in difficulties in the course of surgery. This article summarizes currently available knowledge regarding differences in the level of emitted fluorescence. It may depend on both the histological type and the genetic profile of the tumor, which is reflected in the activity and expression of enzymes involved in the intracellular metabolism of fluorescent dyes, such as PBGD, FECH, UROS, and ALAS. The transport of 5-aminolevulinic acid and its metabolites across the blood–brain barrier and cell membranes mediated by transporters, such as ABCB6 and ABCG2, is also important. Accompanying therapies, such as antiepileptic drugs or steroids, also have an impact on light emission by tumor cells. Accurate determination of the factors influencing the fluorescence of 5-aminolevulinic acid-treated cells may contribute to the improvement of fluorescence navigation in patients with highly malignant gliomas.

Butein Inhibits Oxidative Stress Injury in Rats with Chronic Heart Failure via ERK/Nrf2 Signaling

Background

Chronic heart failure (CHF) is a serious heart disease resulting from cardiac dysfunction. Oxidative stress is an important factor in aging and disease. Butein, however, has antioxidant properties. To determine the effect of butein on oxidative stress injury in rats, a CHF rat model was established.

Methods

The CHF rat model was induced by abdominal aortic coarctation (AAC). Rats in CHF+butein and sham+butein group were given 100 mg/kg butein via gavage every day to detect the effect of butein on oxidative stress injury and myocardial dysfunction. The cardiac structural and functional parameters, including the left ventricular end-systolic dimension (LVESD), the left ventricular end-diastolic dimension (LVEDD), the left ventricular ejection fraction (LVEF), and the left ventricular fractional shortening (LVFS), were measured. Oxidative stress was measured through the production of reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA). Cardiac injury markers like creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), and aspartate aminotransferase (AST) were evaluated. Hematoxylin and eosin (H&E) staining was used to observe the myocardial cell morphology. The effect of butein on the extracellular signal-regulated kinase (ERK)/nuclear factor-E2 p45-related factor (Nrf2) signaling was confirmed by Western blot analysis.

Results

Butein had a significant effect on CHF in animal models. In detail, butein inhibited oxidative stress, relieved cardiac injury, and alleviated myocardial dysfunction. Importantly, butein activated the ERK1/2 pathway, which contributed to Nrf2 activation and subsequent heme oxygenase-1 (HO-1) and glutathione cysteine ligase regulatory subunit (GCLC) induction.

Conclusions

In this study, butein inhibits oxidative stress injury in CHF rat model via ERK/Nrf2 signaling pathway.

Nanogold Particles Suppresses 5-Flurouracil-Induced Renal Injury: An Insight into the Modulation of Nrf-2 and Its Downstream Targets, HO-1 and γ-GCS

The development of the field of nanotechnology has revolutionized various aspects in the fields of modern sciences. Nano-medicine is one of the primary fields for the application of nanotechnology techniques. The current study sheds light on the reno-protective impacts of gold nano-particles; nanogold (AuNPs) against 5-flurouracil (5-FU)-induced renal toxicity. Indeed, the use of 5-FU has been associated with kidney injury which greatly curbs its therapeutic application. In the current study, 5-FU injection was associated with a significant escalation in the indices of renal injury, i.e., creatinine and urea. Alongside this, histopathological and ultra-histopathological changes confirmed the onset of renal injury. Both gene and/or protein expression of nuclear factor erythroid 2-related factor 2 (Nrf-2) and downstream antioxidant enzymes revealed consistent paralleled anomalies. AuNPs administration induced a significant renal protection on functional, biochemical, and structural levels. Renal expression of the major sensor of the cellular oxidative status Nrf-2 escalated with a paralleled reduction in the renal expression of the other contributor to this axis, known as Kelch-like ECH-associated protein 1 (Keap-1). On the level of the effector downstream targets, heme oxygenase 1 (HO-1) and gamma-glutamylcysteine synthetase (γ-GCS) AuNPs significantly restored their gene and protein expression. Additionally, combination of AuNPs with 5-FU showed better cytotoxic effect on MCF-7 cells compared to monotreatments. Thus, it can be inferred that AuNPs conferred reno-protective impact against 5-FU with an evident modulatory impact on Nrf-2/Keap-1 and its downstream effectors, HO-1 and γ-GCS, suggesting its potential use in 5-FU regimens to improve its therapeutic outcomes and minimize its underlying nephrotoxicity.

From Far West to East: Joining the Molecular Architecture of Imidazole-like Ligands in HO-1 Complexes

HO-1 overexpression has been reported in several cases/types of human malignancies. Unfortunately, poor clinical outcomes are reported in most of these cases, and the inhibition of HO-1 is considered a valuable and proven anticancer approach. To identify novel hit compounds suitable as HO-1 inhibitors, we report here a fragment-based approach where ligand joining experiments were used. The two most important parts of the classical structure of the HO-1 inhibitors were used as a starting point, and 1000 novel compounds were generated and then virtually evaluated by structure and ligand-based approaches. The joining experiments led us to a novel series of indole-based compounds. A synthetic pathway for eight selected molecules was designed, and the compounds were synthesized. The biological activity revealed that some molecules reach the micromolar activity, whereas molecule 4d inhibits the HO-1 with an IC₅₀ of 1.03 μM. This study suggested that our joining approach was successful, and a novel hit compound was generated. These results are ongoing for further development.

Physics of biomolecular recognition and conformational dynamics

Biomolecular recognition usually leads to the formation of binding complexes, often accompanied by large-scale conformational changes. This process is fundamental to biological functions at the molecular and cellular levels. Uncovering the physical mechanisms of biomolecular recognition and quantifying the key biomolecular interactions are vital to understand these functions. The recently developed energy landscape theory has been successful in quantifying recognition processes and revealing the underlying mechanisms. Recent studies have shown that in addition to affinity, specificity is also crucial for biomolecular recognition. The proposed physical concept of intrinsic specificity based on the underlying energy landscape theory provides a practical way to quantify the specificity. Optimization of affinity and specificity can be adopted as a principle to guide the evolution and design of molecular recognition. This approach can also be used in practice for drug discovery using multidimensional screening to identify lead compounds. The energy landscape topography of molecular recognition is important for revealing the underlying flexible binding or binding-folding mechanisms. In this review, we first introduce the energy landscape theory for molecular recognition and then address four critical issues related to biomolecular recognition and conformational dynamics: (1) specificity quantification of molecular recognition; (2) evolution and design in molecular recognition; (3) flexible molecular recognition; (4) chromosome structural dynamics. The results described here and the discussions of the insights gained from the energy landscape topography can provide valuable guidance for further computational and experimental investigations of biomolecular recognition and conformational dynamics.

Protective effect of Beta vulgaris roots supplementation on anemic phenylhydrazine-intoxicated rats

Anemia is a public health problem that affects many people worldwide. Beetroot (Beta vulgaris) is a plant supposed to have many healthy features. The present study was done to evaluate the anti-anemic effect of beetroot supplement on anemia induced by phenylhydrazine in albino rats. Fifty rats were randomly divided into five equal groups. The control group was kept normal rats. In the second group, anemia was induced in rats by intraperitoneal injection of phenylhydrazine at 60 mg/kg in 3 divided doses daily, for 3 consecutive days. The last three groups received phenylhydrazine as the anemic group. Then, the third group received beetroot extract in dose 200 mg/kg for 24 days. The fourth group received beetroot powder in dose 1000 mg/kg for 24 days. The last group received iron (III) hydroxide polymaltose complex in dose 5mg/kg for 24 days. Our results showed that hemolytic anemia induced by phenylhydrazine in rats caused alteration in the blood picture, iron indices, serum biochemical parameters, antioxidant biomarkers, and histopathological picture. However, the supplementation with beetroot ameliorated these alterations, especially beetroot powder which showed powerful health effects compared to beetroot extract and iron preparation.

Association between HO‑1 gene promoter polymorphisms and diseases (Review)

Heme oxygenase‑1 (HO‑1) is an inducible cytoprotective enzyme that degrades heme into free iron, carbon monoxide and biliverdin, which is then rapidly converted into bilirubin. These degradation products serve an important role in the regulation of inflammation, oxidative stress and apoptosis. While the expression level of HO‑1 is typically low in most cells, it may be highly expressed when induced by a variety of stimulating factors, a process that contributes to the regulation of cell homeostasis. In the 5'‑non‑coding region of the HO‑1 gene, there are two polymorphic sites, namely the (GT)n dinucleotide and T(‑413)A single nucleotide polymorphism sites, which regulate the transcriptional activity of HO‑1. These polymorphisms have been shown to be closely associated with the occurrence and progression of numerous diseases, including cardiovascular, pulmonary, liver and kidney, various types of cancer and viral diseases. The present article reviews the progress that has been made in research on the association between the two types of polymorphisms and these diseases, which is expected to provide novel strategies for the diagnosis, treatment and prognosis of various diseases.

Syzygium aqueum (Burm.f.) Alston Prevents Streptozotocin-Induced Pancreatic Beta Cells Damage via the TLR-4 Signaling Pathway

Although several treatments are available for the treatment of type 2 diabetes mellitus, adverse effects and cost burden impose the search for safe, efficient, and cost-effective alternative herbal remedies. Syzygium aqueum (Burm.f.) Alston, a natural anti-inflammatory, antioxidant herb, may suppress diabetes-associated inflammation and pancreatic beta-cell death. Here, we tested the ability of the bioactive leaf extract (SA) to prevent streptozotocin (STZ)-induced oxidative stress and inflammation in pancreatic beta cells in rats and the involvement of the TLR-4 signaling pathway. Non-fasted rats pretreated with 100 or 200 mg kg-1 SA 2 days prior to the STZ challenge and for 14 days later had up to 52 and 39% reduction in the glucose levels, respectively, while glibenclamide, the reference standard drug (0.5 mg kg-1), results in 70% reduction. Treatment with SA extract was accompanied by increased insulin secretion, restoration of Langerhans islets morphology, and decreased collagen deposition as demonstrated from ELISA measurement, H and E, and Mallory staining. Both glibenclamide and SA extract significantly decreased levels of TLR-4, MYD88, pro-inflammatory cytokines TNF-α, and TRAF-6 in pancreatic tissue homogenates, which correlated well with minimal pancreatic inflammatory cell infiltration. Pre-treatment with SA or glibenclamide decreased malondialdehyde, a sensitive biomarker of ROS-induced lipid peroxidation, and restored depleted reduced glutathione in the pancreas. Altogether, these data indicate that S. aqueum is effective in improving STZ-induced pancreatic damage, which could be beneficial in treating type 2 diabetes mellitus.

Forensic significance of intracardiac heme oxygenase-1 expression in acute myocardial ischemia

Heme oxygenase-1 (HO-1), an inducible stress-response protein, exerts anti-oxidant and anti-apoptotic effects. However, its significance in forensic diagnosis of acute ischemic heart diseases (AIHD) such as myocardial infarction (MI) is still unknown. We examined the immunohistochemical expression of HO-1 in the heart samples to discuss their forensic significance to determine acute cardiac ischemia. The heart samples were obtained from 23 AIHD cases and 33 non-AIHD cases as controls. HO-1 positive signals in cardiomyocyte nuclear were detected in 78.2% of AIHD cases, however, that were detected in only 24.2% control cases with statistical difference between AIHD and non-AIHD groups. In contrast to HO-1 protein expression, there was no significant difference in the appearance of myoglobin pallor regions and leukocyte infiltration in the hearts between AIHD and non-AIHD groups. From the viewpoints of forensic pathology, intracardiac HO-1 expression would be considered a valuable marker to diagnose AIHD as the cause of death.

Metabolomic alteration induced by psychotropic drugs: Short-term metabolite profile as a predictor of weight gain evolution

Psychotropic drugs can induce strong metabolic adverse effects, potentially increasing morbidity and/or mortality of patients. Metabolomic profiling, by studying the levels of numerous metabolic intermediates and products in the blood, allows a more detailed examination of metabolism dysfunctions. We aimed to identify blood metabolomic markers associated with weight gain in psychiatric patients. Sixty-two patients starting a treatment known to induce weight gain were recruited. Two hundred and six selected metabolites implicated in various pathways were analyzed in plasma, at baseline and after 1 month of treatment. Additionally, 15 metabolites of the kynurenine pathway were quantified. This latter analysis was repeated in a confirmatory cohort of 24 patients. Among the 206 metabolites, a plasma metabolomic fingerprint after 1 month of treatment embedded 19 compounds from different chemical classes (amino acids, acylcarnitines, carboxylic acids, catecholamines, nucleosides, pyridine, and tetrapyrrole) potentially involved in metabolic disruption and inflammation processes. The predictive potential of such early metabolite changes on 3 months of weight evolution was then explored using a linear mixed-effects model. Of these 19 metabolites, short-term modifications of kynurenine, hexanoylcarnitine, and biliverdin, as well as kynurenine/tryptophan ratio at 1 month, were associated with 3 months weight evolution. Alterations of the kynurenine pathway were confirmed by quantification, in both exploratory and confirmatory cohorts. Our metabolomic study suggests a specific metabolic dysregulation after 1 month of treatment with psychotropic drugs known to induce weight gain. The identified metabolomic signature could contribute in the future to the prediction of weight gain in patients treated with psychotropic drugs.

Growing the molecular architecture of imidazole-like ligands in HO-1 complexes

Up-regulation of HO-1 had been frequently reported in different cases and types of human malignancies. Since poor clinical outcomes are reported in these cases, this enzyme's inhibition is considered a valuable and proven anticancer approach. To identify novel HO-1 inhibitors suitable for drug development, we report a structure-guided fragment-based approach to identify new lead compounds. Different parts of the selected molecules were analyzed, and the different series of novel compounds were virtually evaluated. The growing experiments of the classical HO-1 inhibitors structure led us to different hit-compounds. A synthetic pathway for six selected molecules was designed, and the compounds were synthesized. The biological activity revealed that molecules 10 and 12 inhibit the HO-1 activity with an IC₅₀ of 1.01 and 0.90 μM, respectively. This study suggested that our growing approach was successful, and these results are ongoing for further development.

Disturbed Lipid Metabolism in Diabetic Patients with Manifest Coronary Artery Disease Is Associated with Enhanced Inflammation

Background: Diabetic vasculopathy plays an important role in the pathophysiology of coronary artery disease (CAD) with oxidative stress as a strong mediator. This study aims to elucidate the underlying pathomechanisms of diabetic cardiac vasculopathy leading to coronary disease with an emphasis on the role of oxidative stress. Therefore, novel insights into antioxidant pathways might contribute to new strategies in the treatment and prevention of diabetic CAD. Methods: In 20 patients with insulin-dependent or non-insulin dependent diabetes mellitus (IDDM/NIDDM) and 39 non-diabetic (CTR) patients, myocardial markers of oxidative stress, vasoactive proteins, endothelial nitric oxide synthase (eNOS), activated phosphorylated eNOS (p-eNOS), and antioxidant enzymes, e.g., tetrahydrobiopterin generating dihydrofolate reductase (DHFR), heme oxygenase (HO-1), as well as serum markers of inflammation, e.g., E-selectin, interleukin-6 (IL-6), and lipid metabolism, e.g., high- and low-density lipoptrotein (HDL- and LDL-cholesterol) were determined in specimens of right atrial tissue and in blood samples from type 2 diabetic and non-diabetic patients undergoing coronary artery bypass graft (CABG) surgery. Results: IDDM/NIDDM increased markers of inflammation (e.g., E-selectin, p = 0.005 and IL-6, p = 0.051), decreased the phosphorylated myocardial p-eNOS (p = 0.032), upregulated the myocardial stress response protein HO-1 (p = 0.018), and enhanced the serum LDL-/HDL-cholesterol ratio (p = 0.019). However, the oxidative stress markers in the myocardium and the expression of vasoactive proteins (eNOS, DHFR) showed only marginal adverse changes in patients with IDDM/NIDDM. Conclusion: Dyslipidemia and myocardial inflammation seem to be the major determinants of diabetic CAD complications. Dysregulation in pro-oxidative enzymes might be attributable to the severity of CAD and oxidative stress levels in all included patients undergoing CABG.

Leptin Receptor-Deficient db/db Mice Show Significant Heterogeneity in Response to High Non-heme Iron Diet

Recent studies have shown an association between iron homeostasis, obesity and diabetes. In this work, we investigated the differences in the metabolic status and inflammation in liver, pancreas and visceral adipose tissue of leptin receptor-deficient db/db mice dependent on high iron concentration diet. 3-month-old male BKS-Leprdb/db/JOrlRj (db/db) mice were divided into two groups, which were fed with different diets containing high iron (29 g/kg, n = 57) or standard iron (0.178 g/kg; n = 42) concentrations for 4 months. As anticipated, standard iron-fed db/db mice developed obesity and diabetes. However, high iron-fed mice exhibited a wide heterogeneity. By dividing into two subgroups at the diabetes level, non-diabetic subgroup 1 (<13.5 mmol/l, n = 30) significantly differed from diabetic subgroup two (>13.5 mmol/l, n = 27). Blood glucose concentration, HbA1c value, inflammation markers interleukin six and tumor necrosis factor α and heme oxygenase one in visceral adipose tissue were reduced in subgroup one compared to subgroup two. In contrast, body weight, C-peptide, serum insulin and serum iron concentrations, pancreatic islet and signal ratio as well as cholesterol, LDL and HDL levels were enhanced in subgroup one. While these significant differences require further studies and explanation, our results might also explain the often-contradictory results of the metabolic studies with db/db mice.

Associations between blood heavy metal(loid)s and serum heme oxygenase-1 in pregnant women: Do their distribution patterns matter?

The relationship between heavy metal(loid)s exposure and oxidative stress damage is a matter of research interest. Our study aimed to investigate the distribution patterns of the nine heavy metal(loid)s in blood of pregnant women, including four toxic heavy metal(loid)s [arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg)] and five typical heavy metal(loid)s [manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn), and selenium (Se)] in blood. Blood samples of 348 women were collected and their concentrations in the serum (sr) and blood cells (bc) were measured, as well as serum heme oxygenase-1 (HO-1) (an oxidative stress marker). Total blood (tb) concentrations of these metal(loid)s and serum-to-blood cell concentration ratios (sr/bc) were further calculated. We found Cu mainly accumulated in the serum compared to the blood cells with Cu^sr/bc = 2.30, whereas Co, Se, and As evenly distributed between these two fractions. Other metal(loid)s mainly concentrated in the blood cells. Co^sr, Cu^sr, Cu^bc, Mn^bc, Zn^bc, Cd^bc, Co^tb, Cu^tb, Mn^tb, Zn^tb, Cd^tb, and Cu^sr/bc were negatively associated with serum HO-1, whereas As^sr, As^bc, As^tb, Zn^sr/bc, Cd^sr/bc, and Hg^sr/bc were positively, indicating of their potential toxicity. We concluded that the distribution patterns of blood heavy metal(loid)s, in particular for Cd, Hg and Zn, which either increased in serum or decreased in blood cells, might be associated with elevated serum oxidative stress, should be considered in environmental health assessments.

The Novel Antioxidant Compound JSH-23 Prevents Osteolysis by Scavenging ROS During Both Osteoclastogenesis and Osteoblastogenesis

Inflammatory osteolysis is a pathological skeletal disease associated with not only the production of inflammatory cytokines but also local oxidative status. Excessive reactive oxygen species (ROS) promote bone resorption by osteoclasts and induce the apoptosis of osteoblasts. In consideration of the lack of effective preventive or treatments options against osteolysis, the exploitation of novel pharmacological compounds/agents is critically required. In our study, we found that a novel antioxidant compound, JSH-23, plays a role in restoring bone homeostasis by scavenging intracellular ROS during both osteoclastogenesis and osteoblastogenesis. Mechanically, JSH-23 suppressed RANKL-induced osteoclastogenesis, bone resorption and the expression of specific genes (including NFATc1, c-Fos, TRAP, CTSK and DC-STAMP) via inhibition of the NF-κB signaling pathway. Meanwhile, JSH-23 suppressed RANKL-induced ROS generation via the TRAF6/Rac1/NOX1 pathway and the enhanced expression of Nrf2/HO-1. In addition, JSH-23 attenuated H₂O₂-induced apoptosis and mineralization reduction in osteoblasts by reducing ROS production and enhancing Nrf2/HO-1 expression. Our in vivo results further revealed that JSH-23 exerts its protective effects on bone mass through its antioxidant activity. In conclusion, our results show that the application of JSH-23 might be a novel and plausible strategy for the treatment of osteolysis-related disease.

Hemin attenuates response of primary rat adipocytes to adrenergic stimulation

Hemin is an activator of heme oxygenase-1 (HO-1), an enzyme catalyzing heme degradation. Up-regulation of HO-1 is observed in response to various pathological conditions. Moreover, pharmacological activation of HO-1 is associated with numerous beneficial effects in the organism. Hemin was shown to exert, among other, anti-diabetic and anti-obesity properties. These effects are strongly linked with adipose tissue. However, the direct influence of hemin on metabolism of the fat cells have not been explored. The present study aimed to determine the short-term effects of hemin on metabolism of the primary rat adipocytes. We focused on processes directly related to lipid accumulation, such as lipogenesis and lipolysis. For this purpose, the isolated cells were subjected for 2 h to 40 µM hemin, and effects of this compound on insulin-stimulated glucose conversion to lipids, lactate release, lipolysis induced by various stimuli, and also on the antilipolytic action of insulin were determined. It was shown that hemin did not affect insulin-induced lipogenesis and lactate release. However, hemin significantly decreased lipolysis stimulated by epinephrine. The inhibitory effect of hemin on epinephrine-induced lipolysis was not abolished in the presence of SnMP, an inhibitor of HO-1, which suggests hemin action irrespective of this enzyme. Similar inhibitory effects on epinephrine-induced lipolysis were observed in the presence of 3 and 12 mM glucose. Moreover, hemin was shown to reduce epinephrine-induced lipolysis also when glucose was replaced by alanine or by succinate. Apart from changes in epinephrine action, it was found that the lipolytic response of the adipocytes to isoproterenol was also diminished by hemin. However, hemin failed to affect lipolysis stimulated by dibutyryl-cAMP (a direct activator of protein kinase A), forskolin (an activator of adenylate cyclase), and also by DPCPX (an adenosine A₁ receptor antagonist). Additionally, epinephrine-induced lipolysis was shown to be decreased by insulin, and this effect was deepened in the presence of hemin. These results indicate that short-term exposure of the adipocytes to hemin does not affect processes related to glucose metabolism, such as lipogenesis and lactate release. However, hemin was found to decrease the lipolytic response to adrenergic stimulation, which is associated with reduced lipid release from adipocytes. Moreover, our results indicate that hemin is also capable of diminishing the exaggerated lipolysis, which occurs in the presence of supraphysiological concentrations of glucose.

Discovery of Novel Acetamide-Based Heme Oxygenase-1 Inhibitors with Potent In Vitro Antiproliferative Activity

Heme oxygenase-1 (HO-1) promotes heme catabolism exercising cytoprotective roles in normal and cancer cells. Herein, we report the design, synthesis, molecular modeling, and biological evaluation of novel HO-1 inhibitors. Specifically, an amide linker in the central spacer and an imidazole were fixed, and the hydrophobic moiety required by the pharmacophore was largely modified. In many tumors, overexpression of HO-1 correlates with poor prognosis and chemoresistance, suggesting the inhibition of HO-1 as a possible antitumor strategy. Accordingly, compounds 7i and 7l-p emerged for their potency against HO-1 and were investigated for their anticancer activity against prostate (DU145), lung (A549), and glioblastoma (U87MG, A172) cancer cells. The selected compounds showed the best activity toward U87MG cells. Compound 7l was further investigated for its in-cell enzymatic HO-1 activity, expression levels, and effects on cell invasion and vascular endothelial growth factor (VEGF) extracellular release. The obtained data suggest that 7l can reduce cell invasivity acting through modulation of HO-1 expression.

Nrf2 and Heme Oxygenase-1 Involvement in Atherosclerosis Related Oxidative Stress

Atherosclerosis remains the underlying process responsible for cardiovascular diseases and the high mortality rates associated. This chronic inflammatory disease progresses with the formation of occlusive atherosclerotic plaques over the inner walls of vascular vessels, with oxidative stress being an important element of this pathology. Oxidation of low-density lipoproteins (ox-LDL) induces endothelial dysfunction, foam cell activation, and inflammatory response, resulting in the formation of fatty streaks in the atherosclerotic wall. With this in mind, different approaches aim to reduce oxidative damage as a strategy to tackle the progression of atherosclerosis. Special attention has been paid in recent years to the transcription factor Nrf2 and its downstream-regulated protein heme oxygenase-1 (HO-1), both known to provide protection against atherosclerotic injury. In the current review, we summarize the involvement of oxidative stress in atherosclerosis, focusing on the role that these antioxidant molecules exert, as well as the potential therapeutic strategies applied to enhance their antioxidant and antiatherogenic properties.