Vitamin A in health care: Suppression of growth and induction of differentiation in cancer cells by vitamin A and its derivatives and their mechanisms of action

Ultrasound-assisted intensification of Pickering interfacial biocatalysis preparation of vitamin A aliphatic esters

A novel approach to ultrasound-assisted Pickering interfacial biocatalysis (PIB) has been proposed and implemented for the efficient enzymatic transesterification production of vitamin A fatty acid esters. This is the first instance of exploiting the synergistic effect of ultrasound and the bifunctional modification of enzyme supports to accelerate biocatalytic performance in PIB systems. The optimal conditions were determined to be ultrasound power of 70 W, on/off time of 5 s/5 s, substrate molar ratio of 1:1, enzyme addition of 2 %, and a volume ratio of n-hexane to PBS of 3:1, a temperature of 40 °C, and a time of 30 min. The application of ultrasound technology not only improved lipase activity but also allowed for a reduction in emulsion droplet size to enhance interfacial mass transfer.Bifunctional modification of silica-based supports enhanced stability of immobilized enzymes by increasing hydrogen bonding while maintaining the active interface microenvironment. Compared with a non-ultrasound-assisted PIB system stabilized by mono-modified immobilized enzyme particles, the catalytic efficacy (CE) of the novel system reached 8.18 mmol g-1 min-1, which was enhanced by 3.33-fold, while the interfacial area was found to have increased by 17.5-fold. The results facilitated the conversion of vitamin A palmitate (VAP), vitamin A oleate (VAO), vitamin A linoleate (VAL), and vitamin A linolenate (VALn), with conversion rates of approximately 98.2 %, 97.4 %, 96.1 %, and 94.7 %, respectively. This represents the most efficient example that has been reported to our knowledge. Furthermore, the system demonstrated improved reusability, with a conversion rate of 62.1 % maintained even after 10 cycles. The findings presented in this paper provide valuable insights into an efficient and conveniently promising protocol for the development of PIB systems.

Vitamin A ameliorates valproic acid-induced autism-like symptoms in developing zebrafish larvae by attenuating oxidative stress and apoptosis

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social deficits and repetitive/stereotyped behaviors. Prenatal exposure to valproic acid (VPA) has been reported to induce ASD-like symptoms in human and rodents. However, the etiology and pathogenesis of ASD have not been well elucidated. This study aimed to explore the mechanisms underlying VPA-induced ASD-like behaviors using zebrafish model and investigated whether vitamin A could prevent VPA-induced neurotoxicity. Here, zebrafish embryos were exposed to 0, 25 and 50 μM VPA from 4 to 96 h post fertilization (hpf) and the neurotoxicity was assessed. Our results showed that VPA affected the normal development of zebrafish larvae and induced ASD-like behaviors, including reduced locomotor activity, decreased distance near conspecifics, impaired social interaction and repetitive swimming behaviors. Exposure to VPA decreased the GFP signal in transgenic HuC:egfp zebrafish according to the negative effect of VPA on the expression of neurodevelopmental genes. In addition, VPA enhanced oxidative stress by promoting the production of reactive oxygen species (ROS) and hydrogen peroxide (H2O2) and inhibiting the activity of superoxide dismutase, then triggered apoptosis by upregulation of apoptotic genes. These adverse outcomes were mitigated by vitamin A, suggesting that vitamin A rescued VPA-induced ASD-like symptoms by inhibiting oxidative stress and apoptosis. Overall, this study identified vitamin A as a promising strategy for future therapeutic regulator of VPA-induced ASD-like behaviors.

Molecular interaction between myofibrillar protein and beta-carotene during heating

Beta-carotene (β-C) is a natural phytochemical with good functions, but the strong hydrophobicity and acid-base instability limit its absorption in the intestine. A well-designed heat-induced myofibrillar protein (MP) transport system can improve the bioavailability of β-C, and temperature might have a significant impact on this process. This study utilized multispectral, surface plasmon resonance (SPR), and molecular dynamics simulation to investigate the effect of temperature on the interaction between β-C and MP. The results showed that the major interaction between β-C and MP switched from Van der Waals force to hydrophobic interaction at near 37 °C. The changes in the spatial structures of proteins and the thermal motion of molecules may be the main reasons for the transformation of intermolecular interaction. These results indicated that selecting the appropriate temperature is of great significance for designing the transport system of β-C.

Kuijieling decoction regulates the Treg/Th17 cell balance in ulcerative colitis through the RA/RARα signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ulcerative colitis (UC) is an idiopathic intestinal disease characterized by chronic inflammation with unknown etiology. Kuijieling decoction is a traditional Chinese Medicine with unique therapeutic efficacy for UC.

AIM OF THE STUDY

To validate the effects of Kuijieling decoction on vitamin A metabolism and retinoic acid (RA) production, along with evaluation of its immunomodulatory activity, and further clarify the upstream mechanisms underlying Treg/Th17 regulation that contribute to therapeutic effects against UC.

MATERIALS AND METHODS

Network pharmacology and molecular docking analyses were employed to predict the potential anti-UC targets of Kuijieling and associated pathways. A rat model of UC was generated by treatment with trinitrobenzene sulfonic acid (TNBS) to induce inflammation. T lymphocytes were induced to differentiate into Th17 via combined stimulation with the cytokines TGF-β1, IL-6 and IL-23. Expression levels of RA/RARα-related factors (RARα, CRABPII, Smad3, IL-6R and IL-23R) and Treg/Th17 cell-related factors (Foxp3, RORγt) were measured via western blot (WB), quantitative real-time PCR (RT-qPCR), and immunohistochemistry analyses. Components of the vitamin A metabolic pathway (vitamin A, retinol, retinoic acid) and Treg/Th17 cell-related cytokines (IL-10, IL-17, IL-21) were evaluated using ELISA. Flow cytometry was performed to determine the percentages of Treg and Th17 cells.

RESULTS

The action targets of Kuijieling were significantly associated with T cell activation, Th17 cell differentiation and the immune response. IL-2, IL-6, STAT3 and RARα displayed strong binding affinities with the main components of Kuijieling, suggesting an important role in its therapeutic efficacy. Kuijieling promoted vitamin A metabolism and RA/RARα signaling in UC rats and T lymphocytes. Moreover, Kuijieling effectively regulated the Treg/Th17 cell balance in UC rats and T lymphocytes and relieved inflammation. The protective effect of Kuijieling was weakened after inhibition of the RA/RARα signaling pathway.

CONCLUSIONS

Kuijieling promotes vitamin A metabolism and RA synthesis, enhances interactions between RA, intracellular binding protein CRABPII and nuclear receptor RARα, and upregulates Smad3 and Foxp3, thus promoting Treg differentiation. Simultaneously, Kuijieling inhibited expression of IL-6R and IL-23R genes and production of RORγt, leading to suppression of Th17 differentiation, and ultimately, reduction of the Th17/Treg cell ratio.

The relationship between blood vitamin A levels and diabetic retinopathy: a population-based study

We assessed the relationship between blood vitamin A levels and the risk of diabetic retinopathy. The study was population-based epidemiological study for 11,727 participants aged 40 or older who participated in the Korean National Health and Nutrition Examination Survey. Vitamin A in the blood was classified into quartiles. Diabetic retinopathy was diagnosed by the Early Treatment for Diabetic Retinopathy Study. After adjusting confounding variables such as age, sex, smoking, cholesterol, diabetes prevalence period, glycated hemoglobin levels, and high blood pressure, the odd ratio (OR) of vitamin A at quartile level 4 for diabetic retinopathy was 0.32 (95% confidence interval [CI], 0.14-0.72, P for trend < 0.001). In male, the OR of quartile 3 level vitamin A for diabetic retinopathy was 0.11 (95% CI, 0.01-0.69, P for trend = 0.010). In adults under the age of 60, the OR of vitamin A at quartile level 3 for diabetic retinopathy was 0.10. (95% CI, 0.03-0.29, P for trend < 0.001). Serum vitamin A high levels are associated with low risk of diabetic retinopathy. Particularly, there is a more effective relationship in male and adults under the age of 60.

[Prevention and Treatment of Cancer with Vitamin A and Its Derivatives: Cell Differentiation and Proliferation]

Normal differentiation and proliferation of cells are essential for maintaining homeostasis. Following the successful completion of whole genome sequencing, protein modification has been attracted increasing attention in order to understand the roles of protein diversification in protein function and to elucidate molecular targets in mechanisms of signal transduction. Vitamin A is an essential nutrient for health maintenance. It is present as β-carotene in green and yellow vegetables and retinyl ester in animal products and absorbed into the body from the intestines. After ingestion, it is converted to retinol and oxidized in target cells to retinal, which plays critical roles in vision. It is then further oxidized to retinoic acid (RA), which exhibits a number of effects prior to being metabolized by cytochrome P450 and excreted from the body. Since RA exhibits cell differentiation-inducing actions, it is used as a therapeutic agent for patients with acute promyelocytic leukemia. The current paper describes: (1) HL60 cell differentiation and cell differentiation induction therapy by RA; (2) roles played by RA and retinal and their mechanisms of action; (3) retinoylation, post-translational protein-modified by RA, a novel non-genomic RA mechanism of action without RA receptor; (4) new actions of β-carotene and retinol in vivo and (5) potent anticancer effects of p-dodecylaminophenol (p-DDAP), a novel vitamin A derivative created from the RA derivative fenretinide. We propose that nutritional management of vitamin A can be effective at preventing and treating diseases, and that p-DDAP is a promising anticancer drug.

Characterization and therapeutic perspectives of differentiation-inducing therapy in malignant tumors

Cancer is a major public health issue globally and is one of the leading causes of death. Although available treatments improve the survival rate of some cases, many advanced tumors are insensitive to these treatments. Cancer cell differentiation reverts the malignant phenotype to its original state and may even induce differentiation into cell types found in other tissues. Leveraging differentiation-inducing therapy in high-grade tumor masses offers a less aggressive strategy to curb tumor progression and heightens chemotherapy sensitivity. Differentiation-inducing therapy has been demonstrated to be effective in a variety of tumor cells. For example, differentiation therapy has become the first choice for acute promyelocytic leukemia, with the cure rate of more than 90%. Although an appealing concept, the mechanism and clinical drugs used in differentiation therapy are still in their nascent stage, warranting further investigation. In this review, we examine the current differentiation-inducing therapeutic approach and discuss the clinical applications as well as the underlying biological basis of differentiation-inducing agents.

Vitamin A Promotes the Repair of Mice Skeletal Muscle Injury through RARα

Vitamin A (VitA) is an important fat-soluble vitamin which plays an important role in cell growth and individual development. However, the effect of VitA on the repair process of muscle injury and its molecular mechanism are still unclear. In this study, VitA and RA were first added to the culture medium of differentiated cells. We then detected cell differentiation marker proteins and myotube fusion. Moreover, the effects of VitA on RARα expression and nuclear translocation were further examined. The results showed that VitA significantly promoted the differentiation of C2C12, and the expression of RARα was significantly increased. Furthermore, VitA was injected into skeletal muscle injury in mice. HE staining and Western Blot results showed that VitA could significantly accelerate the repair of skeletal muscle injury and VitA increase the expression of RARα in mice. This study provides a theoretical basis for elucidating the regulation mechanism of VitA-mediated muscle development and the development of therapeutic drugs for muscle diseases in animals.

Retinol intake is associated with the risk of chronic kidney disease in individuals with type 2 diabetes mellitus: results from NHANES

The aim of this study was to investigate the potential association between retinol intake and the risk of chronic kidney disease (CKD) in individuals with type 2 diabetes mellitus (T2DM). The study included individuals diagnosed with T2DM between 2009 and 2018 from the NHANES database. Demographic and laboratory test data were collected for these individuals, as well as information on CKD diagnosis. Logistic regression models were utilized to estimate the relationship between different retinol intakes and the risk of CKD in patients with T2DM. A total of 3988 patients were included in the study. The mean prevalence of CKD in the T2DM population in the United States from 2009 to 2018 was 36.98 (0.02)%. Multivariate logistic regression analysis revealed a 26% decrease in the incidence of CKD in individuals with higher retinol intake compared to those with lower retinol intake in T2DM (OR = 0.74; 95% CI 0.56-0.98). Furthermore, an increase in retinol intake per 1-standard deviation (SD) was associated with a 16% decreased risk of the incidence of CKD (OR = 0.84; 95% CI 0.72-0.97). Lower retinol intake is an independent risk factor for the onset of CKD in patients with T2DM, and augmenting moderate quantities of retinol confers potential nephroprotective advantages.

Retinol Saturase Mediates Retinoid Metabolism to Impair a Ferroptosis Defense System in Cancer Cells

Ferroptosis is an iron-dependent form of regulated cell death induced by the lethal overload of lipid peroxides in cellular membranes. In recent years, modulating ferroptosis has gained attention as a potential therapeutic approach for tumor suppression. In the current study, retinol saturase (RETSAT) was identified as a significant ferroptosis mediator using a publicly accessible CRISPR/Cas9 screening dataset. RETSAT depletion protected tumor cells from lipid peroxidation and subsequent cell death triggered by various ferroptosis inducers. Furthermore, exogenous supplementation with retinoids, including retinol (the substrate of RETSAT) and its derivatives retinal and retinoic acid, also suppressed ferroptosis, whereas the product of RETSAT, 13, 14-dihydroretinol, failed to do so. As effective radical-trapping antioxidant, retinoids protected the lipid membrane from autoxidation and subsequent fragmentation, thus terminating the cascade of ferroptosis. Pseudotargeted lipidomic analysis identified an association between retinoid regulation of ferroptosis and lipid metabolism. Retinoic acid, but not 13, 14-dihydroretinoic acid, interacted with its nuclear receptor and activated transcription of stearoyl-CoA desaturase, which introduces the first double bond into saturated fatty acid and thus catalyzes the generation of monounsaturated fatty acid, a known ferroptosis suppressor. Therefore, RETSAT promotes ferroptosis by transforming retinol to 13, 14-dihydroretinol, thereby turning a strong anti-ferroptosis regulator into a relatively weak one.

SIGNIFICANCE

Retinoids have ferroptosis-protective properties and can be metabolized by RETSAT to promote ferroptosis, suggesting the possibility of targeting retinoid metabolism in cancer as a treatment strategy to trigger ferroptosis.

Role of endogenous and exogenous antioxidants in risk of six cancers: evidence from the Mendelian randomization study

Background: Although oxidative stress is known to contribute to cancer, and endogenous and exogenous antioxidants are thought to prevent tumorigenesis by suppressing oxidative stress-induced DNA damage, antioxidants have also been reported to show negative effects on tumor formation, necessitating characterization of the causal associations between antioxidants and cancer risk. Methods: In this study, Mendelian randomization (MR) analysis, primarily inverse-variance weighted MR, was used to assess the causal effect of six endogenous and five exogenous diet-derived antioxidants on the risk of six cancers. MR-Egger intercept test and Cochran's Q statistic were utilized to assess pleiotropy and heterogeneity, respectively. Results: For endogenous antioxidants, a bidirectional two-sample MR analysis was conducted. Our findings suggested that serum albumin has a negative causal association with the risk of prostate cancer [odds ratio (OR) = 0.78, 95% confidence interval (CI): 0.68-0.91, p = 0.001]. The risks of the six cancers showed no significant associations with endogenous antioxidants in the converse MR analysis. For exogenous antioxidants, the unidirectional two-sample MR analysis exhibited a nominal relationship between the serum retinol level and non-small-cell lung cancer risk (OR = 0.29, 95% CI: 0.11-0.76, p = 0.011). Conclusions: Thus, our study revealed the protective effects of genetic susceptibility to high circulating albumin levels on prostate cancer, providing potential targeted interventions for prostate cancer prevention.

Plasma Retinol Concentrations and Dietary Intakes of Mother-Infant Sets in Singleton versus Twin Pregnancy

Vitamin A (retinol) is essential for normal fetal development, but the recommendation for maternal dietary intake (Retinol Activity Equivalent, RAE) does not differ for singleton vs. twin pregnancy, despite the limited evaluation of retinol status. Therefore, this study aimed to evaluate plasma retinol concentrations and deficiency status in mother-infant sets from singleton vs. twin pregnancies as well as maternal RAE intake. A total of 21 mother-infant sets were included (14 singleton, 7 twin). The HPLC and LC-MS/HS evaluated the plasma retinol concentration, and data were analyzed using the Mann-Whitney U test. Plasma retinol was significantly lower in twin vs. singleton pregnancies in both maternal (192.2 vs. 312.1 vs. mcg/L, p = 0.002) and umbilical cord (UC) samples (102.5 vs. 154.4 vs. mcg/L, p = 0.002). The prevalence of serum-defined vitamin A deficiency (VAD) <200.6 mcg/L was higher in twins vs. singletons for both maternal (57% vs. 7%, p = 0.031) and UC samples (100% vs. 0%, p < 0.001), despite a similar RAE intake (2178 vs. 1862 mcg/day, p = 0.603). Twin pregnancies demonstrated a higher likelihood of vitamin A deficiency in mothers, with an odds ratio of 17.3 (95% CI: 1.4 to 216.6). This study suggests twin pregnancy may be associated with VAD deficiency. Further research is needed to determine optimal maternal dietary recommendations during twin gestation.

THE ASSOCIATION BETWEEN COLORECTAL CANCER AND INDEX OF NUTRITIONAL QUALITY (INQ); A CASE-CONTROL STUDY

•Is the Index of Nutritional Quality (INQ) associated with colon cancer? •This study compared the INQ of various dietary components between colorectal cancer patients and healthy controls. A total of 480 participants were enrolled in the study (160 patients with colorectal cancer as a case group and 320 healthy control). The results showed that CRC is significantly associated with INQ for some micronutrients. INQ can be considered as an indicator to assess clinical nutritional problems. Background - The nutritional quality of diet may influence the risk of colorectal cancer (CRC). This study compared the Index of Nutritional Quality (INQ) of various dietary components between colorectal cancer patients and healthy controls. Methods - A total of 480 participants were enrolled in the study (160 patients with colorectal cancer as a case group and 320 healthy control). An analysis was conducted on the general characteristics of the participants, their medical histories, anthropometric indicators, physical activity, alcohol consumption, reproductive history, smoking and food intake. A valid food frequency questionnaire was used to assess nutrient intake and INQ was calculated from daily nutrient intake. Results - A Significant inverse association was found between CRC and INQ for vitamins A (OR=0.01, CI: 0.01-0.01), K (OR=0.04, CI: 0.01-0.15), and B12 (OR=0.71, CI: 0.51-0.98), B5 (OR=0.43, CI: 0.00-0.01), zinc (OR=0.35, CI: 0.13-0.95), and phosphorus (OR=0.17, 0.19-0.94). The association between the INQ of vitamin B12 and zinc with colorectal cancer was disappeared after age adjustment. There was a significant negative association between CRC with the INQ of vitamins A, K, B5, phosphorus, and calcium after further adjustments for gender, BMI, menopausal status, and total energy intake. Conclusion -CRC is significantly associated with INQ for some micronutrients. INQ can be considered as an indicator to assess clinical nutritional problems.

Association between retinol intake and periodontal health in US adults

BACKGROUND

Inflammation and oxidative stress are two hallmarks of periodontitis. Retinol is an antioxidant and suppresses expression of pro-inflammatory factors. However, the evidence for an association between retinol intake and periodontitis is limited. Thus, the aim of this study is to assess the association between retinol intake and periodontal health.

METHODS

Data used in this cross-sectional study from the National Health and Nutrition Examination Survey (NHANES) 2009-2014 (n = 9081). Dietary intake of retinol was measured based on two 24-h dietary recall interviews. The category of periodontitis was defined by the CDC/AAP according to clinical periodontal parameters. Univariate and multivariate logistic regression analyses were applied to investigate the relationship between retinol intake and the risk of periodontitis.

RESULTS

Compared with the lowest tertile, individuals in the highest tertile of retinol intake were less likely to be periodontitis (OR_tertile3vs1 = 0.79, 95% CI: 0.65-0.96). The association was still significant in populations who were less than 60 years old (OR_tertile3vs1 = 0.80, 95% CI: 0.65-0.97), non-Hispanic black (OR_tertile3vs1 = 0.62, 95% CI: 0.42-0.94), PI ≤ 1.3 (OR_tertile3vs1 = 0.72, 95% CI: 0.55-0.93), 1.3 < PI ≤ 3.5 (OR_tertile3vs1 = 0.70, 95% CI: 0.55-0.89), non-smoker (OR_tertile3vs1 = 0.63, 95% CI: 0.48-0.81), obesity (OR_tertile3vs1 = 0.68, 95% CI: 0.49-0.94) and who had not diabetes mellitus (OR_tertile3vs1 = 0.79, 95% CI: 0.65-0.95) or had hypertension (OR_tertile3vs1 = 0.63, 95% CI: 0.47-0.84).

CONCLUSION

Retinol intake is inversely associated with poor periodontal health in US adults.

Dietary Vitamin A Intake and Circulating Vitamin A Concentrations and the Risk of Three Common Cancers in Women: A Meta-Analysis

BACKGROUND

According to relevant clinical research, dietary and circulating antioxidants vitamin A are connected with the risk of breast, cervical, and ovarian cancer in women. However, there was inconsistency between the findings. We completed this meta-analysis at the right moment to address this contradiction of the problem.

METHODS

Web of Science, Embase, and PubMed databases were searched using the proposed search strategy and filtered using the inclusion and exclusion criteria as well as the NOS quality score. As of May 2022, low intake or low concentration was used as a control, and odds ratio (OR) or relative risk (RR) and ninety-five percent confidence intervals (95% CI) were extracted for high intake. Stata 12.0 was used to process the data.

RESULTS

Our meta-analysis included a total of 49 studies, 29 on breast cancer, 10 on ovarian cancer, and 10 on cervical cancer. There were 38 case-control studies included, with 25,363 cases and 42,281 controls; there were 11 cohort studies included, 1,334,176 individuals were followed up, and finally 9496 obtained cancer. The pooled OR value results were as follows: diet or supplements (OR = 0.83, 95% CI 0.76-0.90, I ² = 56.1%) and serum or plasma (OR = 0.96, 95% CI 0.86-1.09, I ² = 29.5%). Subgroup analyses were performed according to cancer type, diet or supplements, serum or plasma, study type, and geographic regions.

CONCLUSIONS

In North American and Asian populations, high dietary consumption of vitamin A or supplements decreases the incidence of three cancers in women, with breast and ovarian cancers being more significant. However, high circulating vitamin A concentrations were not significantly connected with the risk of the three malignancies.

Condensation of acrylonitrile and aryl acetonitrile: construction of α-amino-β-cyano cyclohexene skeletons

A representative condensation of acrylonitrile and aryl acetonitrile has been reported for the synthesis of α-amino-β-cyano cyclohexene. The reaction was carried out mildly in an open environment at room temperature. The scope and versatility of the method have been demonstrated with 20 examples, containing highly active ethynyl groups. Further applications for 4-aminopyrimidine compounds were performed. A mechanism was proposed, involving Michael additions between acrylonitrile and aryl acetonitriles as well as intramolecular condensation.

The immunomodulatory role of all-trans retinoic acid in tumor microenvironment

Retinoids are essential nutrients for human beings. Among them, all-trans retinoic acid (ATRA), considered one of the most active metabolites, plays important roles in multiple biological processes. ATRA regulates the transcription of target genes by interacting with nuclear receptors bonded to retinoic acid response elements (RAREs). Besides its differentiation-inducing effect in the treatment of acute promyelocytic leukemia and some solid tumor types, its immunoregulatory role in tumor microenvironment (TME) has attracted considerable attention. ATRA not only substantially abrogates the immunosuppressive effect of tumor-infiltrating myeloid-derived suppressor cells but also activates the anti-tumor effect of CD8 + T cells. Notably, the combination of ATRA with other therapeutic approaches, including immune checkpoint inhibitors (ICIs), tumor vaccines, and chemotherapy, has been extensively investigated in a variety of tumor models and clinical trials. In this review, we summarize the current understanding of the role of ATRA in cancer immunology and immunotherapy, dissect the underlying mechanisms of ATRA-mediated activation or differentiation of different types of immune cells, and explore the potential clinical significance of ATRA-based cancer therapy.

Advances in pathogenesis and therapeutic strategies for osteoporosis

Osteoporosis, is the most common bone disorder worldwide characterized by low bone mineral density, leaving affected bones vulnerable to fracture. Bone homeostasis depends on the precise balance between bone resorption by osteoclasts and bone matrix formation by mesenchymal lineage osteoblasts, and involves a series of complex and highly regulated steps. Bone homeostasis will be disrupted when the speed of bone resorption is faster than bone formation. Based on various regulatory mechanisms of bone homeostasis, a series of drugs targeting osteoporosis have emerged in clinical practice, including bisphosphonates, selective estrogen receptor modulators, calcitonin, molecular-targeted drugs and so on. However, many drugs have major adverse effects or are unsuitable for long-term use. Therefore, it is very urgent to find more effective therapeutic drugs based on the new pathogenesis of osteoporosis. In this review, we summarize novel mechanisms involved in the pathological process of osteoporosis, including the roles of gut microbiome, autophagy, iron balance and cellular senescence. Based on the above pathological mechanism, we found promising drugs for osteoporosis treatment, such as: probiotics, alpha-ketoglutarate, senolytics and hydrogen sulfide. This new finding may provide an important basis for elucidating the complex pathological mechanisms of osteoporosis and provide promising drugs for clinical osteoporosis treatment.

Simultaneous Quantification of Vitamin A and Derivatives in Cosmetic Products by Liquid Chromatography with Ultraviolet Detection

Vitamin A (retinol) and some of its derivatives are a group of fat-soluble compounds used in cosmetic products as bioactive ingredients. Therefore, it is necessary to perform the quality control of final product to ensure their efficacy and safety. A simple and rapid method to determine retinol, retinal, retinyl acetate, retinyl propionate and retinyl palmitate in cosmetics is presented here. The method is based on vortex and/or ultrasound-assisted leaching of the analytes in ethanol followed by liquid chromatography with ultraviolet detection. The analytical performance of the method was evaluated. It has shown high levels of linearity, at least up to 100 µg mL−1; high precision with RSD values below 14% and high sensitivity with low MLODs ranging between 0.3 × 10−4 and 5.9 × 10−4 % w/w, which are enough to monitor these compounds in cosmetic products. The proposed method was successfully applied to seven commercial cosmetic samples to detect and quantify the target analytes, showing the method is suitable for its employment for quality control in cosmetic industries. Cosmetic samples were spiked at two levels of concentration and recovery values around 100% were obtained, showing no significant matrix effects and, therefore, external calibration was adequate for this determination.