Hypoxic regulation of hypoxia inducible factor 1 alpha via antisense transcription.

Impaired oxygen homeostasis is a frequently encountered pathophysiological factor in multiple complex diseases, including cardiovascular disease and cancer. While the canonical hypoxia response pathway is well characterized, less is known about the role of noncoding RNAs in this process. Here, we investigated the nascent and steady-state noncoding transcriptional responses in endothelial cells and their potential roles in regulating the hypoxic response. Notably, we identify a novel antisense long noncoding RNA that convergently overlaps the majority of the hypoxia inducible factor 1 alpha (HIF1A) locus, which is expressed across several cell types and elevated in atherosclerotic lesions. The antisense (HIF1A-AS) is produced as a stable, unspliced, and polyadenylated nuclear retained transcript. HIF1A-AS is highly induced in hypoxia by both HIF1A and HIF2A and exhibits anticorrelation with the coding HIF1A transcript and protein expression. We further characterized this functional relationship by CRISPR-mediated bimodal perturbation of the HIF1A-AS promoter. We provide evidence that HIF1A-AS represses the expression of HIF1a in cis by repressing transcriptional elongation and deposition of H3K4me3, and that this mechanism is dependent on the act of antisense transcription itself. Overall, our results indicate a critical regulatory role of antisense mediated transcription in regulation of HIF1A expression and cellular response to hypoxia.

Alzheimer's disease-induced phagocytic microglia express a specific profile of coding and non-coding RNAs.

INTRODUCTION: Alzheimer's disease (AD) is a neurodegenerative disease and the main cause of dementia in the elderly. AD pathology is characterized by accumulation of microglia around the beta-amyloid (Aß) plaques which assumes disease-specific transcriptional signatures, as for the disease-associated microglia (DAM). However, the regulators of microglial phagocytosis are still unknown. METHODS: We isolated Aß-laden microglia from the brain of 5xFAD mice for RNA sequencing to characterize the transcriptional signature in phagocytic microglia and to identify the key non-coding RNAs capable of regulating microglial phagocytosis. Through spatial sequencing, we show the transcriptional changes of microglia in the AD mouse brain in relation to Aß proximity. RESULTS: Finally, we show that phagocytic messenger RNAs are regulated by miR-7a-5p, miR-29a-3p and miR-146a-5p microRNAs and segregate the DAM population into phagocytic and non-phagocytic states. DISCUSSION: Our study pinpoints key regulators of microglial Aß clearing capacity suggesting new targets for future therapeutic approaches.

Skeletal and dental changes after maxillary expansion with a bone-borne appliance in young and late adolescent patients.

INTRODUCTION: Rapid palatal expansion is a common therapy during orthodontic treatment and could be a preliminary step for correcting different malocclusions; furthermore, this treatment could be necessary at any age. Different anchorage approaches have been proposed to obtain an effective skeletal result, although every device produces both dental and skeletal effects. This study aimed to compare the dentoskeletal effects of a bone-borne palatal expander considering 2 groups of patients of different ages. METHODS: Twenty-four patients consecutively treated were included in the study; patients were divided into 2 groups according to their age: group 1 with age ≤16 years and group 2 patients >16 years. All patients had a preexpansion cone-beam computed tomography scan; a second scan was required at the end of activations. All patients received a bone-borne appliance anchored on 4 miniscrews. RESULTS: Significant intragroup differences were found for maxillary width and dental diameters. No significant differences were found between groups with regard to longitudinal changes, except for the maxillary right plane. CONCLUSIONS: The use of bone-borne maxillary expansion was effective in generating palatal widening both in growing and young adult patients. No significant skeletal or dental differences were found between groups.

Accuracy of orthodontic movements with 3D printed aligners: A prospective observational pilot study.

Objective: Owing to the availability of 3D software, scanners, and printers, clinicians are encouraged to produce in-office aligners. Recently, a new directprinting resin (Tera Harz TC-85DAC) has been introduced. Studies on its mechanical characteristics and biological effects have been published; however, evidence on its efficacy in orthodontic treatment remains scarce. This pilot study aimed to investigate the accuracy of teeth movement achieved with directprinted aligners. Methods: Seventeen patients (eight males and nine females) with a mean age of 27.67 ± 8.95 years, presenting with dental rotations < 30° and spaces/crowding < 5 mm, were recruited for this study. The teeth movement was planned starting from a T0 digital dental cast. The 3D direct-printed aligners were produced using Tera Harz TC-85DAC resin. Once the orthodontic treatment was completed, a final digital cast was obtained (T1). The planned teeth positions were then superimposed onto the T0 and T1 digital models. The differences between the programmed movements and the achieved overall torque, tip, rotation, and transverse dimensions were assessed using the paired t test or Wilcoxon's signed rank test. Results: The overall accuracies for torque, tip, and rotation were 67.6%, 64.2%, and 72.0%, respectively. The accuracy of the change in transverse diameter was 99.6%. Conclusions: Within the limits of the present pilot study (difficulties with abnormally shaped teeth and use of attachments), it can be concluded that 3D printed aligners can be successfully printed in-house and utilized for mildly crowded cases, with a comparable accuracy of tooth movement to that of other aligners.

Three-dimensional analysis of miniscrew position changes during bone-borne expansion in young and late adolescent patients.

INTRODUCTION: Maxillary expansion in patients at the end of their growth relies on the possibility to use miniscrew supported expanders to apply expansion forces directly to the midpalatal suture. Although miniscrews provide a stable anchorage unit, several studies have reported that they do not remain in exactly the same position during treatment. The aim of the present study was to analyze miniscrew position changes after the expansion using bone-borne appliances in late adolescent patients. METHODS: Nineteen patients (13 females, 6 males), with a mean age of 17.81 (SD = 4.66), were treated with a Bone-Borne Expander Device. The appliance was designed with 4 miniscrews: 2 in the anterior palatal area, at the third rugae level; 2 in the posterior area. A CBCT and an intraoral scan were obtained before treatment (T0), and then, a second CBCT was obtained after the expansion (T1). Data on peri-suture bone thickness were collected at T0, then the CBCTs were superimposed, and changes between mini-screws position on T0 and T1 were evaluated, both by linear and angular displacements. RESULTS: Significant longitudinal differences were found in the distance of the head and the tip of miniscrews measured at the occlusal plane, as well as angular changes. Correlations between displacement measurements and peri-suture bone thickness and height measurements were found as well. CONCLUSIONS: While acting as bone anchor units, miniscrews do not remain in the same position during bone-borne expansion. The amount of displacement was related to peri-sutural total bone height and cortical thickness, especially in the anterior area of the naso-frontal maxillary complex.

Efficacy, safety and tolerability of very low-calorie ketogenic diet in obese women with fibromyalgia: a pilot interventional study.

Introduction: Obesity can worsen fibromyalgia (FM) and very low-calorie ketogenic diet (VLCKD) is a potential therapeutic option for diseases that share clinical and pathophysiological features with FM. In this pilot interventional study, we investigated the effects of VLCKD in obese women with FM. Methods: Female patients with FM and a body mass index (BMI) ≥ 30 kg/m2 were eligible for VLCKD. The ketogenic phase (T0 to T8) was followed by progressive reintroduction of carbohydrates (T8 to T20). Changes in BMI, Fibromyalgia Impact Questionnaire (FIQ), Hospital Anxiety and Depression Scale (HADS), EuroQol 5D (EQ-5D) and 36-item Short Form Health Survey (SF-36) were evaluated. A change of 14% in FIQ was considered clinically relevant. The longitudinal association between BMI and patient-reported outcomes (PROs) was assessed using generalized estimating equations. Results: Twenty women were enrolled. Two discontinued the intervention. The mean age of the 18 patients who reached T20 was 51.3 years and mean BMI was 37.2 kg/m2. All patients lost weight during the first period of VLCKD and this achievement was maintained at T20. Mean BMI decreased from 37.2 kg/m2 at T0 to 34.8 kg/m2 at T4, 33.5 kg/m2 at T8 and 32.1 kg/m2 at T20 (p < 0.001). A significant reduction of mean FIQ from 61.7 at T0 to 37.0 at T4 and to 38.7 at T8 (p < 0.001) was observed and it was maintained at T20 with a mean FIQ of 39.1 (p = 0.002). Similar results were obtained for HADS, EQ-5D and SF-36. Analysing each participant, the reduction of FIQ was clinically meaningful in 16 patients (89%) at T4, in 13 (72%) at T8 and in 14 (78%) at T20. No significant association was observed between change in BMI and improvement of the PROs over time. Adverse effects were mild and transient. No major safety concerns emerged. Conclusion: These are the first data on the efficacy of VLCKD in FM. All patients achieved improvement in different domains of the disease, which was maintained also after carbohydrate reintroduction. Our results suggest that ketosis might exert beneficial effects in FM beyond the rapid weight loss. Clinical trial registration: This trial is registered on ClinicalTrials.gov, number NCT05848544.

Construction of Fusion Protein for Enhanced Small RNA Loading to Extracellular Vesicles.

Extracellular vesicles (EVs) naturally carry cargo from producer cells, such as RNA and protein, and can transfer these messengers to other cells and tissue. This ability provides an interesting opportunity for using EVs as delivery vehicles for therapeutic agents, such as for gene therapy. However, endogenous loading of cargo, such as microRNAs (miRNAs), is not very efficient as the copy number of miRNAs per EV is quite low. Therefore, new methods and tools to enhance the loading of small RNAs is required. In the current study, we developed fusion protein of EV membrane protein CD9 and RNA-binding protein AGO2 (hCD9.hAGO2). We show that the EVs engineered with hCD9.hAGO2 contain significantly higher levels of miRNA or shRNA (miR-466c or shRNA-451, respectively) compared to EVs that are isolated from cells that only overexpress the desired miRNA or shRNA. These hCD9.hAGO2 engineered EVs also transfer their RNA cargo to recipient cells more efficiently. We were not able to detect changes in gene expression levels in recipient cells after the EV treatments, but we show that the cell viability of HUVECs was increased after hCD9.hAGO2 EV treatments. This technical study characterizes the hCD9.hAGO2 fusion protein for the future development of enhanced RNA loading to EVs.

Oral Self-Mutilation in Lesch-Nyhan Patients: A Cross-Sectional Study.

Lesch-Nyhan syndrome (LNS) is a rare genetic condition resulting from an inherited disorder of purine metabolism. It is characterized by the lack of one enzyme, hypoxanthine-guanine phos-phoribosyltransferase (HGPRT), which is responsible for purine salvage. The main manifestations of this syndrome are hyperuricaemia, reduction in cognitive abilities, self-aggressive behavior, choreoathetosis, spasticity, and retarded development. The aim of the study was to investigate the means of treatment and efficacy of prevention of oral self-injury behavior (SIB) in patients with LNS. Information regarding the type and treatment of oral SIB in 19 LSN Italian patients (mean age 23.3 years) was gathered via a structured telephone interview of their parents. A total of 84% of the patients showed some form of self-injury behavior; the first form to manifest itself was finger biting (37%), followed by lip biting (25%), and then tongue biting (18%). Furthermore, 74% of cases featured oral SIB, and tooth extraction was found to be the most frequent form of treatment practiced (71%). This study has revealed the great difficulty parents and carers face in managing forms of oral SIB; dental extraction was the most common choice, despite its invasive nature and far-reaching consequences in regard to the psychosocial status of the patients.

Pulp chamber temperature changes and enamel surface analysis during orthodontic composite removal using 3 different burs in a repeatable approach: an experimental study.

BACKGROUND: During the debonding phase every clinician has to take care of preserving the enamel structure and tooth temperature. The objective of this study is to analyze in vitro the increase of the pulp chamber temperature and the wearing of enamel surface, during adhesive removal after debonding. METHODS: 60 extracted human teeth were selected. An orthodontic bracket was bonded on each tooth and after bracket removal, intraoral scanner pictures were used to evaluate ARI for each tooth. 3 different burs were tested: Tungsten-carbide multiple blade, Arkansas stone and Ceramic bur. A mechanical arm controlled by a dedicated software was used to reproduce a repeatable act of composite removal. To analyze in vitro the pulp chamber temperature during the composite removal procedure, teeth were treated endodontically placing a thermocouple through the root canal from the apex. A software registered temperature changes in a continuous manner. The enamel surface of every tooth was tested after the removal of composite with an optical stereoscopic microscope. RESULTS: An association existed between maximum internal pulp chamber temperature variation and irrigation (P-value < 0.0001) and between maximum internal pulp chamber temperature variation and bur type (P-value = 0.0133), with a significantly lower temperature increase produced by the Arkansas bur. A significant difference among groups was detected for ESI and EDI assessment (P-value = 0.002, P-value = 0.010). CONCLUSIONS: Considering the initial setup, temperature variation analysis showed more conservative results using the Arkansas burs with irrigation. ESI and EDI indexes showed significant enamel surface damage using Tungsten-carbide burs.

Implant Site Changes in Three Different Clinical Approaches: Orthodontic Extrusion, Regenerative Surgery and Spontaneous Healing after Extraction: A Systematic Review.

Both surgical and non-surgical techniques are employed for implant site development. However, the efficacy of these methods has not been thoroughly evaluated and compared. This systematic review aims to compare the biologic, functional and esthetic outcomes of three different approaches before implant placement in both the maxillary and mandibular arches: orthodontic extrusion, regenerative surgery and spontaneous healing after extraction. The systematic research of articles was conducted up to January 2020 in Medline, Scopus and the Cochrane Library databases. Studies were selected in a three-stage process according to the title, the abstract and the inclusion criteria. The methodological quality and the risk of bias of the included studies were evaluated using ROBINS-I tools for non-randomized studies, Rob 2.0 for RCT. Quality evaluation of case reports was performed using CARE guidelines. Through the digital search, 1607 articles were identified, and 25 of them were included in the systematic review. The qualitative evaluation showed a good methodological quality for RCT, sufficient for non-randomized studies and poor for case reports. Based on the available results, both orthodontic extrusion and regenerative surgery allowed the development of the implant site with satisfying esthetic and functional outcomes. Studies about the spontaneous healing of the extraction socket showed resorption of the edentulous ridge, which complicated the implant insertion. No study referred to failures or severe complications. Most of the studies reported only qualitative results. The present systematic review demonstrated that there is a substantial lack of data and evidence to determine which of the presented methods is better for developing a future implant site. Both surgical and non-surgical procedures appear effective in the regeneration of hard tissue, whereas not all the techniques can improve soft tissue volume, too. The orthodontic technique simultaneously enhances both hard and soft tissue.

Nuclear microRNA-466c regulates Vegfa expression in response to hypoxia.

MicroRNAs are well characterized in their role in silencing gene expression by targeting 3´-UTR of mRNAs in cytoplasm. However, recent studies have shown that miRNAs have a role in the regulation of genes in the nucleus, where they are abundantly located. We show here that in mouse endothelial cell line (C166), nuclear microRNA miR-466c participates in the regulation of vascular endothelial growth factor a (Vegfa) gene expression in hypoxia. Upregulation of Vegfa expression in response to hypoxia was significantly compromised after removal of miR-466c with CRISPR-Cas9 genomic deletion. We identified a promoter-associated long non-coding RNA on mouse Vegfa promoter and show that miR-466c directly binds to this transcript to modulate Vegfa expression. Collectively, these observations suggest that miR-466c regulates Vegfa gene transcription in the nucleus by targeting the promoter, and expands on our understanding of the role of miRNAs well beyond their canonical role.

Diets differing in carbohydrate cellularity and amount similarly reduced visceral fat in people with obesity - a randomized controlled trial (CARBFUNC).

BACKGROUND & AIMS: Visceral adipose tissue (VAT) volume is associated with common lifestyle diseases. Dietary quality, including food matrix and degree of carbohydrate cellularity, as well as the carbohydrate/fat ratio, may influence VAT volume. We aimed to determine the effects of isocaloric diets differing in either "cellularity", a novel marker of dietary carbohydrate quality, or carbohydrate amount on visceral fat volume and anthropometric measures in adults with obesity. METHODS: In a randomized controlled trial of 193 people with obesity/central adiposity, we compared changes in VAT volume after 6 and 12 months, measured by abdominal computed tomography, on three isocaloric eating patterns based on "acellular" carbohydrate sources (e.g., flour-based whole-grain products; comparator arm), "cellular" carbohydrate sources (minimally processed foods with intact cellular structures such as fruits, potatoes/tubers, and rice), or low-carbohydrate high-fat (LCHF) principles. Outcomes were compared by an intention-to-treat (ITT) analysis using constrained linear mixed-effects modelling (cLMM) providing baseline-adjusted change scores and proper missing data handling without imputation. RESULTS: 78 and 57 participants completed 6 and 12 months, respectively, with similar intakes of energy (females: 1820-2060 kcal, males: 2480-2550 kcal) and protein (16-17 energy percent, E%) throughout the intervention, and only modest reductions in energy from baseline. Reported dietary intakes were 42-44, 41-42, and 11-15 E% carbohydrate and 36-38, 37-38, and 66-70 E% fat in the acellular, cellular and LCHF groups, respectively. There were no significant between-group differences in VAT volume after 6 months (cellular vs. acellular [95% CI]: -55 cm³ [-545, 436]; LCHF vs. acellular [95% CI]: -225 cm³ [-703, 253]) or after 12 months (cellular vs. acellular [95% CI]: -122 cm³ [-757, 514]; LCHF vs. acellular [95% CI]: -317 cm³ [-943, 309]). VAT volume decreased significantly within all groups by 14-18% and 12-17% after 6 and 12 months, respectively. Waist circumference was reduced to a significantly greater degree in the LCHF vs. acellular group at 6 months (LCHF vs. acellular [95% CI]: -2.78 cm [-5.54, -0.017]). CONCLUSIONS: Despite modest energy restriction, the three isocaloric eating patterns, differing in carbohydrate cellularity and amount, decreased visceral fat volume significantly and to a similar clinically relevant degree. CLINICAL TRIALS IDENTIFIER: NCT03401970. https://clinicaltrials.gov/ct2/show/NCT03401970.

Fibromyalgia: a new facet of the post-COVID-19 syndrome spectrum? Results from a web-based survey.

OBJECTIVE: Postacute COVID-19 syndrome (PACS) is an emerging entity characterised by a large array of manifestations, including musculoskeletal complaints, fatigue and cognitive or sleep disturbances. Since similar symptoms are present also in patients with fibromyalgia (FM), we decided to perform a web-based cross-sectional survey aimed at investigating the prevalence and predictors of FM in patients who recovered from COVID-19. METHODS: Data were anonymously collected between 5 and 18 April 2021. The collection form consisted of 28 questions gathering demographic information, features and duration of acute COVID-19, comorbid diseases, and other individual's attributes such as height and weight. The American College of Rheumatology (ACR) Survey Criteria and the Italian version of the Fibromyalgia Impact Questionnaire completed the survey. RESULTS: A final sample of 616 individuals (77.4% women) filled the form 6±3 months after the COVID-19 diagnosis. Of these, 189 (30.7%) satisfied the ACR survey criteria for FM (56.6% women). A multivariate logistic regression model including demographic and clinical factors showed that male gender (OR: 9.95, 95% CI 6.02 to 16.43, p<0.0001) and obesity (OR: 41.20, 95% CI 18.00 to 98.88, p<0.0001) were the strongest predictors of being classified as having post-COVID-19 FM. Hospital admission rate was significantly higher in men (15.8% vs 9.2%, p=0.001) and obese (19.2 vs 10.8%, p=0.016) respondents. CONCLUSION: Our data suggest that clinical features of FM are common in patients who recovered from COVID-19 and that obesity and male gender affect the risk of developing post-COVID-19 FM.

Food balance sheet and household budget survey dietary data and mortality patterns in Europe.

Worldwide dietary data for nutrition monitoring and surveillance are commonly derived from food balance sheets (FBS) and household budget surveys (HBS). We have compared food supply from FBS and food availability data from HBS among eighteen European countries and have estimated the extent to which they correlate, focusing on food groups which are comparably captured by FBS and HBS and for which there is epidemiological evidence that they can have a noticeable impact on population mortality. Spearman's correlation coefficient was +0.78 (P < 10- 3) for vegetables (including legumes),+0.76 (P < 10- 3) for fruits, +0.69 (P < 10- 3) for fish and seafood and +0.93 (P < 10- 3) for olive oil. With respect to meat and meat products, the coefficient was lower at +0.39 (P = 0.08). Moreover, we have examined whether the supply (FBS) or the availability (HBS) of food groups known or presumed to have beneficial effect on the occurrence of CHD and total cancer can predict overall, coronary and cancer mortality in ecological analyses. After controlling for purchasing power parity-adjusted gross domestic product and tobacco smoking we found that for vegetables, fruits, fish and seafood, as well as for olive oil, both the FBS and the HBS estimates were inversely associated with all three indicators of mortality, although the number of countries with complete information on all study variables hindered formal statistical documentation (P>0.05 in some instances). FBS and HBS have their own strengths and weaknesses, but they may complement each other in dietary assessments at the population level.

Changes in nuclear and cytoplasmic microRNA distribution in response to hypoxic stress.

MicroRNAs (miRNAs) are small non-coding RNAs that have well-characterized roles in cytoplasmic gene regulation, where they act by binding to mRNA transcripts and inhibiting their translation (i.e. post-transcriptional gene silencing, PTGS). However, miRNAs have also been implicated in transcriptional gene regulation and alternative splicing, events that are restricted to the cell nucleus. Here we performed nuclear-cytoplasmic fractionation in a mouse endothelial cell line and characterized the localization of miRNAs in response to hypoxia using small RNA sequencing. A highly diverse population of abundant miRNA species was detected in the nucleus, of which the majority (56%) was found to be preferentially localized in one compartment or the other. Induction of hypoxia resulted in changes in miRNA levels in both nuclear and cytoplasmic compartments, with the majority of changes being restricted to one location and not the other. Notably, the classical hypoxamiR (miR-210-3p) was highly up-regulated in the nuclear compartment after hypoxic stimulus. These findings reveal a previously unappreciated level of molecular complexity in the physiological response occurring in ischemic tissue. Furthermore, widespread differential miRNA expression in the nucleus strongly suggests that these small RNAs are likely to perform extensive nuclear regulatory functions in the general case.

Use of Complementary and Alternative Medicine (CAM) in cancer patients: An Italian multicenter survey.

INTRODUCTION: Complementary and Alternative Medicine (CAM) include a wide range of products (herbs, vitamins, minerals, and probiotics) and medical practices, developed outside of the mainstream Western medicine. Patients with cancer are more likely to resort to CAM first or then in their disease history; the potential side effects as well as the costs of such practices are largely underestimated. PATIENTS AND METHOD: We conducted a descriptive survey in five Italian hospitals involving 468 patients with different malignancies. The survey consisted of a forty-two question questionnaire, patients were eligible if they were Italian-speaking and receiving an anticancer treatment at the time of the survey or had received an anticancer treatment no more than three years before participating in the survey. RESULTS: Of our patients, 48.9% said they use or have recently used CAM. The univariate analysis showed that female gender, high education, receiving treatment in a highly specialized institute and receiving chemotherapy are associated with CAM use; at the multivariate analysis high education (Odds Ratio, (OR): 1.96 95% Confidence Interval, CI, 1.27-3.05) and receiving treatment in a specialized cancer center (OR: 2.75 95% CI, 1.53-4.94) were confirmed as risk factors for CAM use. CONCLUSION: Roughly half of our patients receiving treatment for cancer use CAM. It is necessary that health professional explore the use of CAM with their cancer patients, educate them about potentially beneficial therapies in light of the limited available evidence of effectiveness, and work towards an integrated model of health-care provision.

Vinorelbine and prednisone in older cancer patients with hormone-refractory metastatic prostate cancer. A phase II study.

AIMS AND BACKGROUND: Prostate cancer is a common disease in older men. Since it is hormone resistant, no treatment may improve survival. In patients with hormone-refractory prostate cancer, clinical benefit is an important treatment end point. STUDY DESIGN: This study evaluated the efficacy and toxicity of a vinorelbine and prednisone combination in hormone-refractory prostate cancer patients. Vinorelbine was administered at the dose of 25 mg/m2 on days 1 and 8, every three weeks; prednisone was administered orally at the dose of 12 mg/day. Thirty consecutive patients, 65 years or older, with progressive (PSA increase or increase in bidimensionally measurable lesion) metastatic prostate adenocarcinoma were enrolled. Four patients (13%) had a partial response and 14 (46%) stable disease. Time to progression for the entire group was 4.5 months (range, 2-13) and 7.5 months for the group of responders (range, 3-13). A PSA decrease >50% was registered in 36% of the patients. Pain reduction was recorded in 44.4% of the patients and stability in 14.8%. RESULTS: The treatment was well tolerated and grade 3 toxicity was found in 2 cases of anemia and 2 cases of leukopenia without fever. CONCLUSIONS: The schedule is able to control the evolution of hormone-refractory prostate cancer and to give a clinical benefit. These results provide information for further clinical trials in a large series of elderly cancer patients.

Oxidation reactions of steryl esters in a saturated lipid matrix.

In the present study, the formation and further reactions of intact steryl ester hydroperoxides were followed in a tripalmitin matrix maintained at 100°C. The effects of the acyl moiety and its unsaturation degree, and of the sterol structure were investigated. Intact steryl ester hydroperoxides were isolated from the lipid matrix by a developed solid-phase extraction (SPE) method and were determined by HPLC-ELSD. Further reactions of hydroperoxides were followed by determining secondary oxidation products of sterol by GC-FID/MS and oligomers by HPSEC-RI. The oxidation of sterol decreased when its solubility in the lipid medium was increased by introduction of acyl moiety. Increased unsaturation of the acyl or steryl moiety of steryl ester shortened the induction period and increased the oxidation of both steryl and acyl moieties. Thus, by changing the chemical and physical properties of sterols, their oxidation may be greatly affected.