Key Role of 12-Lipoxygenase and Its Metabolite 12-Hydroxyeicosatetraenoic Acid (12-HETE) in Diabetic Retinopathy

Implications of metabolism on multi-systems healthy aging across the lifespan

Aging is increasingly thought to involve dysregulation of metabolism in multiple organ systems that culminate in decreased functional capacity and morbidity. Here, we seek to understand complex interactions among metabolism, aging, and systems-wide phenotypes across the lifespan. Among 2469 adults (mean age 74.7 years; 38% Black) in the Health, Aging and Body Composition study we identified metabolic cross-sectionally correlates across 20 multi-dimensional aging-related phenotypes spanning seven domains. We used LASSO-PCA and bioinformatic techniques to summarize metabolome-phenome relationships and derive metabolic scores, which were subsequently linked to healthy aging, mortality, and incident outcomes (cardiovascular disease, disability, dementia, and cancer) over 9 years. To clarify the relationship of metabolism in early adulthood to aging, we tested association of these metabolic scores with aging phenotypes/outcomes in 2320 participants (mean age 32.1, 44% Black) of the Coronary Artery Risk Development in Young Adults (CARDIA) study. We observed significant overlap in metabolic correlates across the seven aging domains, specifying pathways of mitochondrial/cellular energetics, host-commensal metabolism, inflammation, and oxidative stress. Across four metabolic scores (body composition, mental-physical performance, muscle strength, and physical activity), we found strong associations with healthy aging and incident outcomes, robust to adjustment for risk factors. Metabolic scores for participants four decades younger in CARDIA were related to incident cardiovascular, metabolic, and neurocognitive performance, as well as long-term cardiovascular disease and mortality over three decades. Conserved metabolic states are strongly related to domain-specific aging and outcomes over the life-course relevant to energetics, host-commensal interactions, and mechanisms of innate immunity.

Untargeted metabolomics uncovers metabolic dysregulation and tissue sensitivity in ACE2 knockout mice

Angiotensin-converting enzyme 2 (ACE2) polymorphisms are associated with increased risk of type 2 diabetes mellitus (T2DM), obesity and dyslipidemia, which have been determined in various populations. Consistently, ACE2 knockout (ACE2 KO) mice display damaged energy metabolism in multiple tissues, especially the key metabolic tissues such as liver, skeletal muscle and epididymal white adipose tissue (eWAT) and show even more severe phenotype under high-fat diet (HFD) induced metabolic stress. However, the effects of ACE2 on global metabolomics profiling and the tissue sensitivity remain unclear. To understand how tissues independently and collectively respond to ACE2, we performed untargeted metabolomics in serum in ACE2 KO and control wild type (WT) mice both on normal diet (ND) and HFD, and in three key metabolic tissues (liver, skeletal muscle and eWAT) after HFD treatment. The results showed significant alterations in metabolic profiling in ACE2 KO mice. We identified 275 and 168 serum metabolites differing significantly between WT and ACE2 KO mice fed on ND and HFD, respectively. And the altered metabolites in the ACE2 KO group varied from 90 to 196 in liver, muscle and eWAT. The alterations in ND and HFD serum were most similar. Compared with WT mice, ACE2 KO mice showed an increase in N-phenylacetylglutamine (PAGln), methyl indole-3-acetate, 5-hydroxytryptophol, cholic acid, deoxycholic acid and 12(S)-HETE, while LPC (19:0) and LPE (16:1) decreased. Moreover, LPC (20:0), LPC (20:1) and PC (14:0e/6:0) were reduced in both ND and HFD serum, paralleling the decreases identified in HFD skeletal muscle. Interestingly, DL-tryptophan, indole and Gly-Phe decreased in both ND and HFD serum but were elevated in HFD liver of ACE2 KO mice. A low level of l-ergothioneine was observed among liver, muscle, and epididymal fat tissue of ACE2 KO mice. Pathway analysis demonstrated that different tissues exhibited different dysregulated metabolic pathways. In conclusion, these results revealed that ACE2 deficiency leads to an overall state of metabolic distress, which may provide a new insight into the underlying pathogenesis in metabolic disorders in both ACE2 KO mice and in patients with certain genetic variant of ACE2 gene.

Targeting inflammation as cancer therapy

Inflammation has accompanied human beings since the emergence of wounds and infections. In the past decades, numerous efforts have been undertaken to explore the potential role of inflammation in cancer, from tumor development, invasion, and metastasis to the resistance of tumors to treatment. Inflammation-targeted agents not only demonstrate the potential to suppress cancer development, but also to improve the efficacy of other therapeutic modalities. In this review, we describe the highly dynamic and complex inflammatory tumor microenvironment, with discussion on key inflammation mediators in cancer including inflammatory cells, inflammatory cytokines, and their downstream intracellular pathways. In addition, we especially address the role of inflammation in cancer development and highlight the action mechanisms of inflammation-targeted therapies in antitumor response. Finally, we summarize the results from both preclinical and clinical studies up to date to illustrate the translation potential of inflammation-targeted therapies.

Apple consumption affects cecal health by regulating 12S-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid (12(S)-HETE) levels through modifying the microbiota in rats

Apples are rich in many nutrients and functional components. However, the mechanism of the effect of fresh apple consumption on rats remains unclear. In the present study, fresh apples (10 g kg-1) were added to the diet of Wistar rats, and changes in the microbiota and metabolite content of the cecum were analyzed after 28 days of feeding, and changes in the 12S-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid (12(S)-HETE) content and indicators related to inflammation, oxidative stress, and apoptosis were detected. Subsequently, a fecal microbiota transplantation (FMT) protocol was designed and carried out to verify the relationship between the microbiota and 12(S)-HETE, the cecal structure, and inflammatory factors. The results show that apple consumption significantly reduced the serum levels of alanine aminotransferase (ALT) and immunoglobulin G (IgG), altered the cecal histomorphology, and significantly upregulated the gene expression of claudin-1 and zonula occludens-1 (ZO-1), which encode tight junction proteins. Apple consumption also changed the structure of the cecal microbiota, increasing the abundance of some species (such as Shuttleworthia) and decreasing the abundance of others (such as Alphaproteobacteria). Metabolomic screening identified 64 significantly different metabolites. The FMT results showed that apple consumption reduced 12(S)-HETE metabolite levels in the cecal contents, improved the intestinal structure, and reduced the levels of proinflammatory factor expression by altering the cecal microbiota. In conclusion, this study provides further insight into the effects of apples on animals using rats as experimental animals. It provides basic data for future exploration of the mechanisms of the effect of apple consumption on humans.

Lipoxygenase-12 Levels and Biochemical Parameters in Iraqi Patients With Type 2 Diabetes With and Without Benign Prostatic Hyperplasia

Background Diabetes mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemia caused by a defect in the secretion or action or both of insulin. It has a complex pathogenesis. Benign prostatic hyperplasia (BPH) refers to an increase in the size of the prostate; it is one of the most common health problems in men that manifests with age. Lipoxygenase-12 (Lipox-12) is one of the enzymes in the Lipox 12/15 family, which plays a major role in catalyzing a variety of polyunsaturated fatty acids (PUFAs) that are capable of producing different metabolites. Lipox-12 has a significant effect on arachidonic acid metabolism, with PUFA, a pro- and anti-inflammatory mediator, as one of the enzyme isoforms. It also plays a major role in modulating inflammation at multiple checkpoints as diabetes progresses. The present study aims to measure Lipox-12 levels in patients with DM type 2 (DM2) and patients with DM2 + BPH. Methodology This study was conducted in Musayyib General Hospital, south of Baghdad, where a clinical examination was performed on 50 samples from controls (healthy subjects), 50 patients with DM2, and 50 patients with DM2 + BPH after taking each patient's history. The examinations performed included fasting blood sugar (FBS), hemoglobin A1c (HbA1c), prostate-specific antigen (PSA), triglycerides (TG), cholesterol (Chol), and Lipox-12. Results The results showed that both the DM2 and DM2 + BPH groups had higher FBS, HbA1c, TG, and Chol levels than healthy subjects; in contrast, Lipox-12 levels were the lowest in the DM2 group (sensitivity = 79% and specificity = 81%) but higher in the DM2 + BPH group (sensitivity = 80%; specificity = 82%) compared to the control group. Conclusions Lipox-12 had a high sensitivity and specificity in the DM2 and DM2 + BPH groups compared to the control group, and in both cases, it was used to monitor and diagnose DM2 and BPH.

Increased serum 12-hydroxyeicosatetraenoic acid levels are correlated with an increased risk of diabetic retinopathy in both children and adults with diabetes

PURPOSE

To investigate the relationship between serum 12-Hydroxyeicosatetraenoic acid (12-HETE) and diabetic retinopathy (DR) in children with type 1 diabetes mellitus (T1DM) and adults with type 2 diabetes mellitus (T2DM).

METHODS

Children from the Shanghai Children and Adolescent Diabetes Eye (SCADE) study and adults from the Shanghai Cohort Study of Diabetic Eye Disease (SCODE) were examined in 2021. Serum 12-HETE levels were detected and compared. Multivariate logistic regression was used to analyze the relationship between 12-HETE and the rate of DR in diabetic patients.

RESULTS

The child study included 4 patients with new-onset DR and 24 patients with T1DM without DR. In children with T1DM, the 12-HETE level was significantly higher in those with DR (P = 0.003). The adult study had two sets, for testing and verification. The test set included 28 patients with new-onset DR and 24 T2DM patients with a course of ≥ 20 years who had never developed DR. The verification set included 41 patients with DR, 50 patients without DR and 50 healthy controls. In the adult test set, the 12-HETE level was significantly higher in patients with DR than in those with T2DM without DR (P = 0.003). In the verification set, the 12-HETE level of patients with DR was significantly higher than that of patients without DR (P < 0.0001) and the healthy controls (P < 0.0001). Multivariate logistic regression indicated that 12-HETE was independently associated with DR in both children (odds ratio [OR] 1.06, 95% confidence interval [CI] 1.00-1.13, P = 0.041) and adults (test set [OR 9.26, 95% CI 1.77-48.59, P = 0.008], verification set [OR 10.49, 95% CI 3.23-34.05, P < 0.001]).

CONCLUSION

Higher serum 12-HETE levels are positively correlated with an increased risk of DR in children with T1DM and adults with T2DM.