Incidence and risk factors for developing chemotherapy-induced neuropathic pain in 500 cancer patients: A file-based observational study

OBJECTIVE

To define the incidence and risk factors for developing chemotherapy-induced neuropathic pain (CINP).

METHODS

Retrospective, file-based analysis on cancer patients who received any type of conventional chemotherapy and for whom neurological evaluation was asked to reveal the extent of chemotherapy-induced peripheral neurotoxicity (CIPN) with or without CINP. CINP was assessed by means of the PI-NRS and Douleur Neuropathique-4 questionnaire. The total neuropathy score-clinical version graded the severity of CIPN.

RESULTS

The medical files of 500 chemotherapy-treated cancer patients were reviewed. Any grade chronic CIPN was disclosed in 343 (68.6%) patients and CINP in 127 (37%) of them, corresponding to an overall percentage of 25.4% among all 500 included patients. The logistic regression analysis identified as independent predictors for CINP development the presence of uncomplicated diabetes (OR: 2.17; p = .039) and grade 2-3 chronic CIPN (OR: 1.61; p < .001) as also the administration of combined paclitaxel plus cisplatin (reference variable), compared to oxaliplatin (OR: 0.18; p = .001) and taxanes (OR: 0.16; p < .001). The increased severity of acute OXAIPN was associated with CINP (OR: 4.51; p < .001). OXA-treated patients with persistent CINP presented a worst likelihood to improve after chemotherapy discontinuation, than patients receiving combined paclitaxel plus cisplatin (OR: 50; p < .001).

CONCLUSION

The incidence of CINP in our cohort was comparable to previous reports, with severities fluctuating upwards during chemotherapy and declined post-chemotherapy. Uncomplicated diabetes, the combined paclitaxel plus cisplatin treatment and the increased severity of acute oxaliplatin neurotoxicity mostly increase the risk for developing CINP. OXA-treated patients present less possibilities to recover from CINP after chemotherapy discontinuation, than other chemotherapies.

Visual and semi-quantitative analysis of 6-[18F]FDOPA PET/CT in patients with brain tumors and suspected tumor recurrence versus radionecrosis

INTRODUCTION

Amino acid PET is a tool recommended by the main neuroimaging societies in the differential diagnosis between radionecrosis (RNC) and umour recurrence (TR) in brain tumours, but its use in our country is still limited. The aim of this work is to present our experience with 6-[18F]FDOPA PET/CT (FDOPA) in brain tumours (primary and M1), comparing these results with other published results.

MATERIAL AND METHODS

Retrospective study of 62 patients with suspected tumour recurrence (TR): 42 brain metastases (M1) and 20 primary, who underwent FDOPA. Images were analysed visually and semi-quantitatively, obtaining SUVmax and SUVmaxlesion/SUVmaxstriatum (L/S) and SUVmaxlesion/SUVmaxcortex (L/C) ratios. The diagnostic validity of PET was analysed and the best performing cut-off points were calculated. PET results were compared with clinical-radiological follow-up and/or histopathology.

RESULTS

TR was identified in 49% of M1 and 76% of brain primaries. The best performing FDOPA interpretation was visual and semi-quantitative, with a sensitivity and specificity in primaries of 94% and 80% and in M1s of 96% and 72% respectively. The cut-off points with the best diagnostic performance were L/C1.44 in M1 and L/C1.55 in primaries. There are discrepant results with other published results.

CONCLUSION

FDOPA PET/CT is a useful tool in the differential diagnosis between recurrence and RNC in brain tumours. It is needed a standardization to contribute to homogenise FDOPA results a inter-centre level.

P16.01.A Factors predicting cognitive impairment after intrathecal methotrexate treatment in patients with non-small cell lung cancer and leptomeningeal disease

Background

Leptomeningeal disease (LD) is a devastating cancer-related neurological complication. LD accounts for 4-15% of patients with non-small cell lung cancer (NSCLC). In this population, the median overall survival (OS) with intrathecal (IT) methotrexate (MTX) plus systemic therapy (ST) is 4-6 months (m). Until now, disease and treatment-related cognitive impairment (CI) has been poorly studied in this group.

Material and Methods

Patients with NSCLC and LD treated with IT MTX in our institution between 2010 and 2021 were retrospectively studied. LD was diagnosed based on positive cerebrospinal fluid cytology or radiological findings in the brain/spinal MRI plus suitable clinical signs/symptoms. IT MTX (12mg twice weekly for 4 weeks, then 12mg weekly for 4 weeks) was given in combination with ST. Patients’ clinical characteristics and patient-reported CI were assessed at baseline and at 3-months post IT MTX. A Kaplan-Meier survival analysis was performed. Primary endpoint: predictive factors of CI at 3m post IT MTX. Secondary endpoint: prognostic factors.

Results

Out of 55 patients included, 51% were male and median age at LD diagnosis was 59 years old (range 38-78). Most patients had an ECOG PS≤1 (76.4%) and adenocarcinoma histology (83.6%). 47% of patients harbored EGFR mutation. In 23.6% of patients LD was diagnosed synchronously with lung tumor and for patients without LD at tumor diagnosis, the median time to LD development was 8m (range 0-73). Clinical features at LD diagnosis were 43.7% infratentorial symptoms, 29% CI, 20% multiple symptoms and 7% asymptomatic. At LD diagnosis, 53% of patients had synchronous brain metastases (BM) and in 38% the systemic disease was not controlled. 85.5% of patients received ST concurrently with IT MTX (N=22 chemotherapy, N=22 TKIs and N=3 immunotherapy). 14.5% of patients did not receive ST.

Median OS from IT was 5m (95% CI 1.3-8.6). ECOG PS and ST administered concurrently with IT MTX was associated with longer OS (p&lt;0.05). 23.6% of patients developed CI at 3m post IT therapy. Median OS for patients without and with CI post IT therapy was 6m (95% CI 0.7-11.3) vs 4m (95% CI 0.5-75) respectively (p=0.15). Patients with leukoencephalopathy at baseline (score≥2in the periventricular Fazekas’ score) (p=0.033), women (p&lt;0.01) and those ≥60 years (p=0.04) were more likely to present CI 3m post IT MTX. The presence of cardiovascular risk factors, previous brain radiotherapy and concurrent BM was not statistically associated with CI.

Conclusion

In this cohort, 24% of patients with NSCLC and LD treated with IT MTX will develop CI 3m post treatment. Baseline leukoencephalopathy, female gender, elder than 60 years old were more likely to exhibit CI after IT MTX. A better characterization of these patients is warranted to develop new treatment strategies to prevent/reduce CI.

Prospectively Assessing Serum Neurofilament Light Chain Levels As A Biomarker Of Paclitaxel-Induced Peripheral Neurotoxicity In Breast Cancer Patients

Our aim was to assess the significance of measuring serum neurofilament light chain (sNfL) levels as biomarker of paclitaxel-induced peripheral neurotoxicity (PIPN). We longitudinally measured sNfL in breast cancer patients, scheduled to receive the 12-weekly paclitaxel-based regimen. Patients were clinically examined by means of the Total Neuropathy Score-clinical version (TNSc), while sNfL were quantified, using the highly-sensitive Simoa technique, before starting chemotherapy (Baseline), after 2 (week-2) and 3 (week-3) weekly courses, and at the end of chemotherapy (week-12). Among 59 included patients (mean age: 53.1±11.5 years), 33 (56%) developed grade 0-1 and 26 (44%) grade 2-3 PIPN at week-12. A significant longitudinal increase of sNfL levels from baseline to week-12 was determined, whereas patients wth TNSc grade 2-3 PIPN had significantly increased sNfL levels at week-12, compared to those with grade 0-1. ROC analysis defined a value of NfL of >85 pg/mL at week-3 as the best discriminative determination to predict the development of grade 2-3 PIPN at week-12 (sensitivity 46.2%, specificity 84.8%). The logistic binary regression analysis revealed that age >50 years and the cutoff of >85 pg/mL of sNfL levels at week-3 independently predicted the development of grade 2-3 PIPN at week-12 with a sensitivity of 46%, a specificity of 91%, and a positive and negative predictive values of 75% and 67%, respectively. sNfL levels seem to be a valuable biomarker of neuro-axonal injury in PIPN. Early increase of this biomarker after a 3 weekly chemotherapy course can be a predictive marker of final PIPN severity. This article is protected by copyright. All rights reserved.

[Historical perspective of the studies with the greatest impact on the treatment of gliomas]

Historically, advances in our knowledge of neuro-oncology and improvements in the survival of patients with brain tumours have been relatively scarce. One of the main turning points can be established from 2005 onwards, when the potential therapeutic role of cytostatics in these tumours was confirmed, thus changing the standard of treatment. Up until that date, only radiation therapy and surgery were considered truly effective treatments. This shift has contributed to the development of new systemic therapies and to an in-depth study of gliomagenesis. Advances in the knowledge of the basic fields of brain tumours have helped improve the design and results of new clinical trials, while clinical outcomes provide feedback and new data to further the understanding of these tumours. However, these promising advances open up new unresolved questions and offer a critical approach to the interpretation of past studies. This review mainly updates the results of trials that changed or modified the clinical practice of the treatment and management of gliomas. Commenting on relevant basic research papers that have not yet been translated into the implementation of changes in the treatment of these patients is excluded.

Acute symptomatic seizures and epilepsy after mechanical thrombectomy. A prospective long-term follow-up study

INTRODUCTION

New treatments for acute ischaemic stroke, such as mechanical thrombectomy, can achieve reperfusion of large ischaemic tissue. Some studies have suggested that reperfusion therapies can increase the risk of suffering acute symptomatic seizure (ASS) and poststroke epilepsy (PSE). The aim of the study was to determine the incidence of ASS and PSE in patients undergoing thrombectomy, and related factors.

PATIENTS AND METHODS

This was a retrospective single-centre study including patients with ischaemic stroke and NIHSS> 8 treated with thrombectomy with a follow-up ≥5 years. We evaluated several epidemiological, radiological, clinical and electroencephalographic variables.

RESULTS

Of the 344 included patients, 21 (6.1%) presented ASS, 53 (15.40%) died in the acute phase, and 13 (4.46%) died during the first year. The degree of reperfusion (p 0.029), advanced age (p 0.035), and haemorrhagic transformation (p 0.038) increased the risk of suffering ASS, with degree of reperfusion being an independent factor, OR 2.02 (1.21-4.64). The incidence of PSE was 4.12% in the first year, 3.72% in the second, and 1.61% in the fifth. The accumulated incidence at 5 years was 8.93%. Related risk factor for suffering PSE was ASS (p < 0.001), yielding an OR value of 2.00 (1.28-3.145).

CONCLUSIONS

Thrombectomy doesn´t increase the risk of ASS. A higher percentage of reperfusion, advanced age, and haemorrhagic transformation are associated with an increased risk of ASS. ASS is a risk factor for suffering PSE. In terms of mortality, having suffered ASS and/or PSE does not increase acute or long-term mortality.

Perilesional edema in brain metastases as predictive factor of response to systemic therapy in non-small cell lung cancer patients: a preliminary study

BACKGROUND

The significance of upfront systemic therapies as an alternative to whole brain radiotherapy (WBRT) for multiple brain metastases (BM) is debatable. Our purpose is to investigate if peritumoral edema could predict the intracranial response to systemic chemotherapy (chemo) in patients with advanced non-squamous non-small cell lung cancer (non-SQ-NSCLC) and synchronous multiple BM.

METHODS

In this observational cohort study, we evaluated the outcome of 28 patients with multiple BM (≥3) treated with chemo based on cisplatin/carboplatin plus pemetrexed (chemo, group A, n=17) or WBRT plus subsequent chemo (group B, n=11). The intracranial response, assessed by the response assessment neuro-oncology (RANO) BM criteria, was correlated with the degree of BM-associated edema estimated by the maximum diameter ratio among fluid attenuated inversion recovery (FLAIR) and gadolinium-enhanced T1WI (T1Gd) per each BM at the baseline brain magnetic resonance imaging (MRI).

RESULTS

No differences were observed in baseline characteristics between both groups, except for the number of patients under steroid treatment that was clearly superior in group B (P=0.007). Median OS was similar between groups. Regarding FLAIR/T1Gd ratio (F/Gd), patients treated with chemo alone exhibited significantly higher values (P=0.001) in those who developed intracranial progression disease (PD) (2.80±0.32 mm), compared with those who achieved partial response (PR) (1.30±0.11 mm) or stable disease (SD) (1.35±0.09 mm). In patients treated with WBRT, F/Gd ratio was not predictive of response.

CONCLUSIONS

Peritumoral edema estimated by F/Gd ratio appears a promising predictive tool to identify oligosymptomatic patients with multiple BM in whom WBRT can be postponed.

Late effects of cancer treatment: consequences for long-term brain cancer survivors

Late adverse effects of cancer treatments represent a significant source of morbidity and also financial hardship among brain tumor patients. These effects can be produced by direct neurologic damage of the tumor and its removal, and/or by complementary treatments such as chemotherapy and radiotherapy, either alone or combined. Notably, young adults are the critical population that faces major consequences because the early onset of the disease may affect their development and socioeconomic status. The spectrum of these late adverse effects is large and involves multiple domains. In this review we classify the main long-term adverse effects into 4 sections: CNS complications, peripheral nervous system complications, secondary neoplasms, and Economic impact. In addition, CNS main complications are divided into nonfocal and focal symptoms. Owing to all the secondary effects mentioned, it is essential for physicians to have a high level of clinical suspicion to prevent and provide early intervention to minimize their impact.

Defining a Standardized Information Model for Multi-Source Representation of Breast Cancer Data

This work aims to define a standardized information model for representation of multiple data sources in breast cancer. A set of data elements has been identified using ICHOM Breast Cancer as the minimum data set and adapting it to the needs of Hospital Universitario 12 de Octubre. With this, an information model has been defined according to ISO 13606 and SNOMED CT standards.

Incidence and characteristics of neurotoxicity in immune checkpoint inhibitors with focus on neuromuscular events: Experience beyond the clinical trials

Immune checkpoint inhibitors (ICIs) are associated with various neurological adverse events (NAEs). We herein explored the incidence and clinical phenotype of immune-related NAEs in cancer patients. Medical records of ICI-treated cancer patients were reviewed between the years 2010 and 2018, with an aim to characterize immuno-related NAEs. A total of 1185 ICIs-treated patients were identified, 63.7% of which were males and 36.3% were females, with a mean age of 63.4 ± 7.3 years. Twenty-four from the overall ICIs-treated patients (2%) developed NAEs. No differences were identified in terms of age, sex, tumor type and class of ICIs between the patients who developed NAEs and those who did not. The median number of cycles of ICI treatment before NAEs onset were 4.5 (1-10), and the median time was 102 days. Peripheral nervous system (PNS) involvement was present in 14 patients (58.4%) and central nervous system (CNS) involvement in 10 (33.3%), including 2 patients with aseptic meningitis and polyradicular involvement. Amongst PNS complications, there were five (20.8%) with axonal sensory neuropathies, four (16.7%) with Guillain-Barre-like syndromes, and four (16.7%) with myositis and/or myasthenic syndromes. The majority of patients with PNS-related NAEs (n = 11; 78.6%) improved after ICIs discontinuation and treatment with immune-modulating therapies. The time to neuromuscular toxicities onset was significantly shorter, compared to CNS NAEs (median 70 vs 119 days, P = .037). Immune-related NAEs mostly present with neuromuscular complications. Discontinuation of ICIs and appropriate treatment should be commenced early throughout the process, in order to maximize a favorable outcome.

P10.04 Incidence and characteristics of neurological adverse events secondary to immunotherapy with checkpoint inhibitors

BACKGROUND

To explore the incidence and clinical phenotype of serious neurological adverse events (NAEs) in cancer patients who received immunotherapy with checkpoint inhibitors (ICIs) at two institutions.

MATERIAL AND METHODS

We reviewed files of cancer patients who were treated with ICIs from 2010 to 2018 and then searched for ICIs-related NAEs.

RESULTS

We identified 1185 ICIs-treated patients. Males and females were 63.7% and 36.3%, respectively, with a mean age of 63.4±7.3 years-old. Nivolumab was given to 536 (45.2%) patients, Pembrolizumab to 301 (25.4%) patients, Atezolizumab to 135 (11.4%), Ipilimumab to 104 (8.8%), Durvalumab-Tremelimumab to 77 (6.5%), and other ICIs to 32 (2.8%). Of those patients, 24 (2%) developed a ICI-related NAE. No differences were identified in age, sex, tumor type and class of ICIs between patients who developed neurotoxicity compared to those without neurologic adverse events. The distribution of NAE by agent was: Nivolumab (2.1%), Pembrolizumab (2%), Atezolizumab (1.5%), Ipilimumab (1%), Durvalumab-Tremelimumab (3.9%), and others (2.8%). The median number of cycles received before NAEs onset were 4.5 (1–10), and the median time was 110 days. PNS involvement was evident in 14 patients (58.3%) and CNS involvement in 41.7%, while 2 patients with aseptic meningitis also presented polyradicular involvement. Among PNS complications, there were 5 cases (20.8%) with axonal sensory neuropathies, 4 (16.7%) with Guillain-Barre-like syndromes, 4 (16.7%) with muscle involvement (myositis and myasthenias), and one with other syndromes. Seven patients (50%) with PNS-related NAEs were treated with steroids, 2 (14.3%) with IVIG, and 5 (35.7%) remained untreated. In general the outcome was good after ICIs discontinuation, with about half of patients improving or completely resolving NAEs.

CONCLUSION

ICIs-related NAE although rare overall, might be severe, and are mostly represented by neuromuscular complications. Early discontinuation of ICIs and possibly treatment with immune-modulating therapies should early be initiated to achieve a favourable neurological outcome

P14.93 The utility of the brain 18-FDG-PET and perfusion magnetic resonance imaging in the radionecrosis differential diagnosis

BACKGROUND

Radiation-induced necrosis (RDN) is a side effect observed in patients who underwent stereotactic radiosurgery (SRS) alone or combined with whole brain radiotherapy (WBRT) as treatment for their brain tumors. Nowadays, RDN diagnosis and differentiation from tumor progression using the standard imaging techniques represents a challenge, and histological diagnosis still is the gold standard.Our aim is to assess the positive and negative predictive values (PPV, NPV) of FDG-PET and perfusion magnetic resonance imaging (MRI) in RDN diagnosis.

MATERIAL AND METHODS

From our Pathology department database, all patients with RDN or mixed (tumor plus RDN) brain lesions diagnosis during last 5 years were reviewed. Demographic, clinical and oncologic treatment characteristics were recorded. MRI and FDG-PET images at the suspicion (clinical or radiological) of progression or RDN were registered and compared with the definite diagnosis provided by the tissue sample analysis. Sensitivity, specificity, as such as PPV and NPV for perfusion MRI sequences and FDG-PET image analysis were calculated.

RESULTS

162 patients underwent SRS+/- WBRT in a 5 year period. During follow-up, 11 patients had surgery-confirmed RDN. There are 11 patients (3 women) with 12 lesions, 3 from a breast cancer, 6 from a lung tumor, 1 from a melanoma, 1 atypical meningioma and 1 glioblastoma. 9 of them were treated with both SRS and WBRT, and the 3 others with WBRT alone. The mean age was 65.36 (range: 44–77) years. The median time between the completion of radiation therapy and the suspicion of RDN was 19.7 (range: 3–34) months. With the evolution, it was observed an evident increase in the size of surronding oedema (2–6 times) by FLAIR RMI. We estimate a PPV 0.40 and NPV 0.80 for perfusion MRI, and PPV 0.25 and NPV 0.75 for FDG-PET, respectively.

CONCLUSION

The diagnostic performance of both techniques in our series is low and similar to published data; therefore its results must be carefully interpreted in each case. It is peremptory to implement new diagnostic tools in the standard of care with better diagnostic outcomes.

Influence of oleoyl-estrone treatment on circulating testosterone. Role of 17beta-hydroxysteroid dehydrogenase isoenzymes

Overweight male rats received oral oleoyl-estrone (OE) for 10 days, and were compared with controls. The expression of 17beta-hydroxysteroid dehydrogenase (17betaHSDH) isoenzymes, and other proteins related to sex hormone metabolism, were analyzed in testicle, liver, adrenals and two white adipose sites: subcutaneous inguinal and epididymal pads using a semiquantitative RT-PCR method. Androstenedione, testosterone, estrone and estradiol levels were measured by HPLC-MS/MS. Isoenzyme expressions were grouped according to their main physiological function (oxidative or reductive) and preferred substrate (androgen or estrogen). As expected, testicle was the main site for synthesis of testosterone and estradiol, and the liver the main organ oxidizing them to androstenedione and estrone. Overall oxidative capacity was 6.5-fold higher than the reductive, and estradiol synthesis and oxidation potential were higher than for testosterone. OE decreased serum androgens, and increased estrone, but not estradiol. This was due to decreased testicle ability to produce testosterone, because of smaller size and decreased 17betaHSDH3 expression, but also to lower availability of precursors. High estrone availability (from OE hydrolysis) does not translate into higher estradiol because of decreased testicle reductive 17betaHSDH expression and decreased aromatase. In consequence, we can assume that OE effects on androgens, and the hypothalamic-pituitary-gonadal axis are limited to testicles.

Intestinal oleoyl-estrone esterase activity in the Wistar rat

Low-dose oral oleoyl-estrone (OE) (i.e. in dairy products) is hydrolysed to estrone, which promotes growth and fat deposition. However, pharmacological doses of OE are absorbed largely intact and elicit fat losses. Thus, in order to find out how the intestine handles OE, esterase activity (at pH 5, 7 or 8) was measured in rat stomach, duodenum, jejunum, ileum, cecum, large intestine, and liver using OE as substrate. There were no sex-related differences. Pure pancreatic cholesterol-ester esterase hydrolysed OE even in the absence of taurocholate. The differences in the pH-related activity distribution pattern and selective inhibition and taurocholate dependence show that, in addition to the luminal (i.e. pancreatic) cholesterol-ester esterase, other esterases hydrolyse OE; these combined activities may be sufficient to rapidly dispose of pharmacological doses of OE. Female rats received a tritium-labeled OE gavage; the luminal and tissue label content were measured up to 24 h. The high retention of label in the stomach suggest that this may be a significant site of absorption. The rapid decrease of label in intestinal lumen (and rat tissues) shortly after the administration, hint at rapid absorption and disposal. In conclusion, the high OE-esterase activity and early absorption of OE are indicative of upper gastro-intestinal tract absorption skipping most of the medium-tract esterases.

In the rat, estrone sulphate is the main serum metabolite of oral oleoyl-estrone

Two different oral doses of oleoyl-estrone: 1 and 10 nmol/g a day were given once to male Wistar rats. The serum levels of free estrone, estrone sulphate, estradiol, and acyl-estrone were measured at intervals up to 72 h after the gavage. Oleoyl-estrone was rapidly absorbed; with the 1 nmol/g dose no changes were observed in plasma acyl-estrone but levels increased dramatically with 10 nmol/g, peaking at 6 h; high acyl-estrone levels were maintained up to 24 h, returning to normalcy at 48 h. With the 10 nmol/g dose, free estrone at most doubled its levels but estrone sulphate concentrations rose by one order of magnitude; in both cases, the increases soon (2 h) reached a plateau that was maintained for almost two days. Estradiol levels remained unchanged except for a transient peak at 2 h at the 10 nmol/g dose. The relationship between free estrone and its sulphate was linear, and those of estrone and estrone sulphate versus acyl-estrone showed the existence of an upper serum concentration limit for both molecules. The results hint at estrone sulphate being an important metabolite of oleoyl-estrone disposal, confirm the limited estrogenic response to oleoyl-estrone administration and agree with a rapid absorption and disposal of oleoyl-estrone, nevertheless maintaining high circulating levels of the ester for a time after its oral administration.

The conjugated linoleic acid ester of estrone induces the mobilisation of fat in male Wistar rats

We investigated whether the substitution of the fatty acid moiety in oleoyl-estrone (OE) by conjugated linoleic acid, i.e. conjugated linoleoyl-estrone (cLE) may help improve the antiobesity effects of OE. Overweight (17% fat) male rats were treated for 10 days with oral OE or cLE (10 nmol/g per day) and compared with controls receiving only the oily vehicle. Rat weight and food intake were measured daily. After killing by decapitation, body composition and main plasma parameters were analysed. cLE induced marked decreases in body weight, energy intake, carcass energy and body lipid, whilst sparing protein; the effects were not significantly different from those obtained with OE. Energy expenditure was unchanged, but energy intake decreased to 46% (OE) or 55% (cLE) of controls; whole body energy decreased by 29% (OE) or 24% (cLE) in the 10-day period studied. Plasma composition showed almost identical decreases in glucose and cholesterol elicited by OE and cLE, with a more marked decrease in triacylglycerols by OE and no effect of either on NEFA. OE decreased leptin and insulin levels, but the effects of cLE were more marked on both, with similar decreases in adiponectin. It can be concluded that cLE is a new drug of the OE family; its overall effects on energy were akin to those of OE, albeit fractionally less effective at the single dose tested. However, this lower potency on lipid mobilisation does not affect other effects, such as powerful hypercholesterolemic effects or the modulation of adiponectin. And last, but not least, cLE seems to produce a more marked decrease in leptin and insulin than OE, which may reflect a coordinate action of the conjugated linoleic acid moiety and the "OE effect" on target tissues. If that were the case, cLE may constitute an improvement over OE in its action on insulin resistance.

Combined effects of oral oleoyl-estrone and limited food intake on body composition of young overweight male rats

OBJECTIVE

The combined effects of limited food intake and OE treatment have been analysed in order to determine whether hypocaloric diets enhance the slimming effects of OE on mature overweight male rats. Two levels of dietary limitation at 50 and 25% of a standard intake were established, roughly corresponding to the human LCDs and VLCDs.

DESIGN

Wistar male rats (6 weeks old) were made overweight by a cafeteria diet. After transition to standard diet, they were subjected to food restriction: down to 50 or 25% with respect to the transition period. Half the animals were given daily oral gavages of 10 nmol/g oleoyl-estrone (OE), and the rest received only the vehicle during 10 days.

MEASUREMENTS

Changes in weight and body composition: water, lipid, protein or gross energy were determined by comparing the final pool size with that of day 0, calculated from the initial body weight and the composition of untreated rats. Energy and nitrogen balances were estimated. Plasma levels of metabolites and hormones were also measured.

RESULTS

OE induced changes in body composition similar to those elicited by a 50% reduction in food, with massive loss of lipid and energy. OE-treated rats ate less than the controls, but additional effects on body composition on reduced diet were minimal. OE improved metabolic homoeostasis: better maintained glycaemia, lower cholesterol and shallower hormonal changes, but at the expense of slightly increased protein mobilisation.

CONCLUSIONS

The data presented suggest that no advantages are accomplished by combining OE treatment and hypocaloric diets compared with OE alone, at least under the experimental conditions tested, since the effects were not additive. Despite OE affecting food intake, mechanisms other than that are deemed responsible for the mobilisation of body fat, since intake alone cannot explain the effects on body weight, nor the metabolic and hormonal changes in OE-treated rats. It is concluded that the combination of food restriction and OE may result in unwanted increased protein mobilisation with no synergy between both slimming treatments.

Short-term oral oleoyl-estrone treatment increases plasma cholesterol turnover in the rat

OBJECTIVE

Oral treatment with oleoyl-estrone induces the loss of body fat and improvement of insulin resistance. Since cholesterol levels are deeply affected by oleoyl-estrone, we investigated here whether short-term treatment affected cholesterol turnover and overall metabolite changes.

DESIGN

Wistar female rats received a single oral dose of 10 mumol/kg oleoyl-estrone in 0.2 ml of sunflower oil. Groups of animals were killed at timed intervals and blood samples were taken. In a second experiment series, rats had implanted carotid and jugular cannulas and were given a single gavage of oleoyl-estrone. These rats were used for the measurement of the cholesterol turnover rate.

MEASUREMENTS

Body weight change and food intake: Glucose, total and HDL-cholesterol, triacylglycerols, 3-hydroxybutyrate, nonesterified fatty acids, insulin, HOMA score in the rats of the first series. Cholesterol: Cholesterol pool changes and cholesterol turnover rates in the rats of the second series.

RESULTS

OE induced early effects, decreasing food intake, cholesterol and HDL-cholesterol levels, and increasing insulin sensitivity (HOMA score). OE also increased cholesteryl-ester turnover, and decreased circulating total cholesterol, especially esterified cholesterol pools.

CONCLUSIONS

The role of early changes in insulin sensitivity induced by oral OE cannot explain per se the deep changes in cholesterol handling, essentially a consequence of accelerated lipoprotein turnover. However, the increase in cholesteryl-ester turnover observed with OE treatment may be, at least in part, a consequence of the decrease in insulin resistance. The compounded effect of increased insulin sensitivity and accelerated lipoprotein turnover may help explain the early and marked hypocholesterolaemic effects of OE.

Strain variability in Zucker rats affects their response to oral oleoyl-estrone

There is a considerable variability in the responses of Zucker fa/fa rats in metabolic studies, which could not be solely attributed to the leprfa mutation. In order to fathom the extent of this variability, we compared the response to oleoyl-estrone (OE), a powerful lipid-mobilising agent, of two strains of Zucker lean and obese rats: Harlan (H) and Charles River (CR). Rats were given an oral gavage of 10 micromol/day/kg of OE in sunflower oil, and were compared with oil-receiving controls. Body composition, energy and water balances, and plasma parameters were studied after 10 days of treatment. H rats showed a higher water turnover than CR rats; OE treatment reduced water intake, partly compensated by metabolic water, and decreased stool water. H rats accrued more cholesterol than CR animals, which showed higher cholesterolaemia. OE facilitated cholesterol disposal in lean (CR and H) and H obese rats. CR rats had higher body and liver lipids than H animals. No differences in energy balance were found. Insulin decrease following OE treatment was greater in lean CR than in H rats, but this trend was reversed in the obese rats, lacking effective responses to leptin. The red cell glucose compartment was smaller in H than in CR rats; the higher insulin levels in H rats may be partly responsible for that difference. Obese H maintained glycaemia (and liver glycogen) with higher insulin levels than CR animals. The extent to which the leprfa mutation affects the responses of Zucker fa/fa rats could not be singled out unless the metabolic environment of the batch used is known. This variability must be taken into account when developing a metabolic or hormonal study in which this model of obesity is used.

Technical note: Measurement of total estrone content in foods. Application to dairy products

Estrone is a powerful growth-inducing hormone that is present in milk, mainly in the form of fatty acid esters, at concentrations that promote growth in experimental animals. We present here a method useful for the measurement of this natural hormone in foods and applied it to several common dairy products. Samples were frozen, finely powdered, and lyophilized then extracted with trichloromethane/methanol; the dry extract was saponified with potassium hydroxide. The free estrone evolved was extracted with ethyl acetate and was used for the estimation of total estrone content through radioimmunoassay. Application of the method to dairy products showed high relative levels of total estrone (essentially acyl-estrone) in milk, in the range of 1 microM, which were halved in skimmed milk. Free estrone levels were much lower, in the nanomolar range. A large proportion of estrone esters was present in all other dairy products, fairly correlated with their fat content. The amount of estrone carried by milk is well within the range, where its intake may exert a physiological response in the sucklings for which it is provided. These growth-inducing and energy expenditure-lowering effects may affect humans ingesting significant amounts of dairy products.

Posterior fixation of subaxial cervical spine fractures in patients with ankylosing spondylitis

Cervical spine fractures in patients with ankylosing spondylitis are serious and potentially lethal injuries with high complication rates. Treatment obstacles include long lever arms that generate large forces on any fixation device, osteoporosis, and, usually, kyphotic deformity. The Olerud Cervical Fixation System (OC), with cervical pedicle screws and rods, offers an opportunity to create a biomechanically stable posterior fixation in these complicated cases. The present study is a retrospective chart review and a radiological follow-up of patients with this diagnosis, treated at our department between 1995 and 2000. Nineteen patients (two women) with a mean age of 60 years (32-78 years) were included. The fracture levels were predominantly C5-C6 (five patients) and C6-C7 (five patients). All patients were treated with a long posterior fixation with the OC, and in four patients this was combined with an anterior plate fixation. One patient with severe lordosis also received a short posterior plate fixation. The patients' notes and plain radiographs have been reviewed. Five patients died during the post-operative follow-up period; the others had a mean follow-up time of 24 months (10-55 months). Eleven patients had no neurological deficits preoperatively. One of them developed moderate weakness in his right arm, postoperatively, due to a misplaced pedicle screw in the right pedicle of C5. However, after extraction of the screw he almost totally recovered in 6 months. Eight patients had neurological deficits. Two were paraplegic; two had motor weakness combined with sensory deficiency, and four had a sensory deficiency. Two of the patients with neurological deficits improved postoperatively, but the others were unchanged. Peroperative problems were recorded in five patients; one C6 pedicle was perforated, and two patients had pedicles on one or more levels that the surgeon was not able to probe. In one of the latter patients, transfacet screws were chosen, instead, for one of the levels. Extensive peroperative bleeding was encountered in two patients. One deep-wound infection was noted, postoperatively, and required surgical drainage, but no patients have been re-operated due to loosening of the instrument or to healing problems. In conclusion, the results of the present study indicate that the OC--and possibly other similar long-fixation systems that allow using both pedicle screws and lateral mass screws rigidly connected to a rod--is suited for treating subaxial cervical spine fractures in patients with ankylosing spondylitis, allowing high healing rates.

Effect of oral oleoyl-estrone on the energy balance of diabetic rats

We studied the effects of a 10-day oral 10 micromol/kg oleoyl-estrone (OE) treatment on streptozotocin-diabetic Wistar, Goto-Kakizaki and control Wistar rats. Streptozotocin rats lost more than half the energy ingested as urine glucose. Oleoyl-estrone induced the loss of body weight (mainly body fat) in all groups. Energy expenditure was similar in the three groups of rats studied. Water turnover was deranged in streptozotocin rats, which spent 14% of energy available heating the water drunk. Body lipids were highest in Goto-Kakizaki; lipid levels in streptozotocin rats were very low. Oleoyl-estrone decreased body lipid content in Wistar and Goto-Kakizaki; oleoyl-estrone decreased triacylglycerols (44% in Wistar and Goto-Kakizaki and 22% in streptozotocin rats) and phospholipids but did not affect body cholesterol. Oleoyl-estrone decreased insulin and leptin, did not affect blood glucose but decreased plasma glucose in all groups. There were no changes in plasma triacylglycerols or fatty acids, but HDL, LDL and cholesterol decreased in all groups. The same effects of OE on insulin, plasma (but not blood) glucose and leptin were observed in both models, but the presence of insulin seems to be needed for OE to normalise glycaemia and to facilitate the uptake and utilisation of glucose by tissues. This different handling of glucose and triacylglycerol energy accounts for the disparate effects of OE on energy balance. The main conclusion of this study is that OE function as a lipid-mobilising hormone is dependent on the mass of reserves available, which in turn is closely related to insulin status. Lack of insulin thus results in limited OE effects, and insulin resistance does not prevent or limit the effects of OE on energy homeostasis or the mobilisation of fat.

Zucker obese rats store less acyl-estrone than lean controls

OBJECTIVE

To measure acyl-estrone levels in the plasma of Zucker obese rats. If these are lower than expected on the basis of their body-fat content, as observed in morbidly obese humans, this might provide a possible link relating obesity and low body estrone levels. We also examined the effect of pharmacological treatment with oral oleoyl-estrone on the accumulation of estrone.

DESIGN

Undisturbed Wistar, Goto-Kakizaki and Zucker (lean Fa/?and obese fa/fa) rats were used to determine the relation between circulating acyl-estrone and body lipids, as well as the total body estrone/lipid ratios. One group of Wistar rats was used to measure the effect of oral gavages of oleoyl-estrone (from 0 to 20 micromol/kg/day) for 10 days on the body content of estrone.

MEASUREMENTS

Body weight change and food intake. Total estrone intake, estrone accrual and excretion (by difference) in rats receiving oleoyl-estrone. Total body lipid and estrone. Circulating acyl-estrone levels.

RESULTS

In lean rats (Wistar, Zucker and Goto-Kakizaki) there was a direct relation between body lipid content and circulating acyl-estrone; this relation was not found in Zucker obese rats. The estrone/lipid mass ratio was in a similar range in lean rats, but obese animals showed much lower values. Wistar rats receiving pharmacological doses of oleoyl-estrone did not accumulate significant amounts of estrone, but excreted almost all the estrone ingested.

CONCLUSIONS

The pharmacological administration of acyl-estrone to rats does not result in the accrual of estrone within a wide range of doses, which confirms the safety of this compound. In rats there is a similar relation between the percentage of body lipids and circulating acyl-estrone to that found in humans. Likewise, obese rats showed lower levels of acyl-estrone than expected. The total content of estrone in the bodies of obese rats was also lower than expected from their high lipid content, which suggests that obese rats are deficient in acyl-estrone.

Posterior atlanto-axial fusion with the Olerud Cervical Fixation System for odontoid fractures and C1-C2 instability in rheumatoid arthritis

In posterior C1-C2 fusion, traditional wire fixation gives poor stability. The bone quality is often insufficient to provide the competent structural bone graft that is required, and the introduction of sublaminar wires is somewhat dangerous. The stability is markedly improved by adding transarticular screws, but the drawbacks of structural bone graft and sublaminar wires remain. The C1 claw of the Olerud Cervical Fixation System improves C1-C2 fixation without relying on structural bone graft or compromising the spinal canal. The aim of this study was to evaluate radiological healing and possible complications in a consecutive series of C1-C2 fusions from our department operated with the C1 claw device. Twenty-six patients (14 women) with a mean age of 73 (range 37-93) years were included. The diagnoses were odontoid fracture in 18 patients, rheumatoid instability in 6, and odontoid non-union and os odontoideum in 1 each. The patients were followed clinically and with plain radiographs for an average of 15 (range 3-27) months. There were no neurological or vascular complications, and no secondary displacements or reoperations in the series. Twenty patients followed for 6-27 months were radiographically healed. Six patients died from unrelated causes 1-38 months postoperatively. Three of these patients had no radiographs later than the postoperative control, one had a healed odontoid fracture but resorbed bone graft at 8 months, while the remaining two patients were not healed, but showed no signs of healing disturbance at the time of death. On the basis of the findings of this study, posterior C1-C2 fusion with the Olerud Cervical Fixation System seems promising. No serious complications related to the surgical procedure were encountered. The stability of the implant obviates the use of a solid bone block as a graft and still allows a high frequency of fusion healing.

Effect of oral oleoyl-estrone on adipose tissue composition in male rats

OBJECTIVE

To determine whether the oral administration of oleoyl-estrone has similar mass-decreasing effects on the main different sites of white adipose tissue (WAT).

DESIGN

Adult male Zucker lean rats were given a daily oral gavage of oleoyl-estrone (OE, 10 micromol/kg) in 0.2 ml of sunflower oil for 10 days, and were compared with controls receiving only the oil. The mass of the main WAT sites: subcutaneous, epididymal, mesenteric, retroperitoneal, gluteal, perirenal and interscapular, as well as perirenal and interscapular brown adipose tissue (BAT), were dissected and studied.

MEASUREMENTS

The tissue weight, DNA, protein, lipid and total cholesterol content, together with the levels of leptin and acyl-estrone in the larger WAT and BAT masses, were measured.

RESULTS

The weights of WAT depots were correlated with body weight but those of BAT were not. Cell size was maximal for epididymal and mesenteric and minimal for subcutaneous and retroperitoneal WAT and BAT. Differences were detected in DNA, and in protein and lipid content between distinct WAT sites. OE treatment tended to decrease cell number and cell size in WAT; only small differences in composition were found between WAT locations inside the visceral cavity and those outside. Decreases in lipid content were maximal in mesenteric fat. Leptin and acyl-estrone content were fairly uniform at the different WAT sites, except for high concentrations in gluteal WAT. OE induced a greater decrease in leptin and acyl-estrone than in DNA and lipids; changes in these hormones were fairly parallel in all sites.

CONCLUSIONS

In general, the differences in composition between visceral and peripheral subcutaneous WAT and their responses to OE were less marked than the individual differences observed between specific sites, regardless of location. WAT sites are fairly diverse in composition, but their response to OE treatment was uniform. OE decreased the weight of WAT through reduction of both cell numbers and size; but did not change the mass or composition of BAT significantly. The effects of OE are more marked in the hormonal signals (leptin and acyl-estrone) from the tissue than in its composition and mass.

Induction of acetylcholinesterase expression during apoptosis in various cell types

Acetylcholinesterase (AChE) plays a key role in terminating neurotransmission at cholinergic synapses. AChE is also found in tissues devoid of cholinergic responses, indicating potential functions beyond neurotransmission. It has been suggested that AChE may participate in development, differentiation, and pathogenic processes such as Alzheimer's disease and tumorigenesis. We examined AChE expression in a number of cell lines upon induction of apoptosis by various stimuli. AChE is induced in all apoptotic cells examined as determined by cytochemical staining, immunological analysis, affinity chromatography purification, and molecular cloning. The AChE protein was found in the cytoplasm at the initiation of apoptosis and then in the nucleus or apoptotic bodies upon commitment to cell death. Sequence analysis revealed that AChE expressed in apoptotic cells is identical to the synapse type AChE. Pharmacological inhibitors of AChE prevented apoptosis. Furthermore, blocking the expression of AChE with antisense inhibited apoptosis. Therefore, our studies demonstrate that AChE is potentially a marker and a regulator of apoptosis.

Comparison of the effects of human erythrocyte ghosts and intact erythrocytes on platelet interactions with subendothelium in flowing blood

We investigated whether ghosts behaved similarly to intact erythrocytes to maintain regular primary hemostasis under flow conditions. To this end we performed perfusion experiments with whole blood in which erythrocytes were replaced by pink ghosts, and platelet interaction with the subendothelial surface of a damaged vessel was morphometrically evaluated. The same objective was sought by means of studies with a platelet function analyzer (PFA-100(TM) instrument). Perfusions performed with control blood reconstituted with intact erythrocytes gave rise to 0.4+/-0.2% contact but not spread platelets, 10.8+/-3.4% adhering and spread platelets, 16.3+/-4.6% platelets in thrombi, with 27.5+/-7.4% of the surface covered. Even though the average diameter of the ghosts was smaller than that of intact erythrocytes (5.3 microm vs. 7.7 microm), the values obtained in perfusions performed with ghosts were similar to those of the erythrocyte controls. Studies performed with the PFA-100(TM) analyzer were consistent with those observed in perfusion studies. The viscosity of control blood was compared with that of blood reconstituted with ghosts. At shear rates lower than 450 s(-1), the viscosity of the ghost samples was higher than that of the controls, but the difference progressively decreased as shear rate increased up to 750 s(-1) (3.61+/-0.15 and 3.71+/-0.17 cP, respectively). In conclusion, the results of our study showed that ghosts behaved similarly to intact erythrocytes in maintaining a normal platelet interaction with digested subendothelium, under conditions of moderate shear rate and constant hematocrit (40%). The rheological activity of ghosts, bodies that are metabolically less active, was sufficient for them to satisfactorily act as substitutes for intact erythrocytes in our system.

Effect of oral oleoyl-estrone treatment on plasma lipoproteins and tissue lipase activities of Zucker lean and obese female rats

OBJECTIVE

To study the effect of oral oleoyl-estrone on the plasma lipoprotein profile and tissue lipase activities in order to determine the handling of circulating lipids by adipose tissue, liver and muscle of obese female rats.

DESIGN

Lean (Fa/?) and obese (fa/fa) female Zucker rats treated for 10 days with a daily gavage of 0.2 ml sunflower oil containing 0 (controls) or 10 micromol/kg of oleoyl-estrone. After sacrifice, samples of tissues and plasma were taken.

MEASUREMENTS

Plasma lipoprotein classes and composition; lipoprotein lipase and hepatic lipase activities in plasma, liver, skeletal muscle and periovaric and mesenteric white adipose tissue (WAT).

RESULTS

Oleoyl-estrone decreased plasma cholesterol (mainly in HDLs: 76%) of lean rats, but dramatically decreased all lipid classes in obese rats, in which chylomicra and VLDL lost most of their triacylglycerols (95 and 81%, respectively). Hepatic lipase activity decreased markedly with oleoyl-estrone in all groups, both in plasma (79% lean, 100% obese) and liver (62% in both groups). Lipoprotein lipase activity was largely unchanged by oleoyl-estrone in lean rats, but in the obese it decreased in WAT (82% in periovaric, and 49% in mesenteric), and increased in plasma (x4) and in skeletal muscle (x5); liver levels showed no change.

CONCLUSIONS

The shift observed in obese rats from a decrease in liver and WAT lipoprotein lipase and hepatic lipase activities to an increase in muscle lipoprotein lipase is coincident with the hypolipemic effect of oleoyl-estrone, especially in obese rats, and indicates that muscle is a key site for the disposal of endogenous fat mobilized due to oleoyl-estrone treatment.

Modulation by leptin, insulin and corticosterone of oleoyl-estrone synthesis in cultured 3T3 L1 cells

Preadipocytes (3T3 L1) were used between 7 and 14 days after differentiation; they were incubated with 44 nM 3H-esterone. The medium was supplemented with 1 microM recombinant murine leptin, 10 nM recombinant human insulin, or 1 microM corticosterone for up to 72 hr. In a second series of experiments, cells were incubated for 48 hr with different concentrations of leptin, insulin or corticosterone, and compared with controls (plain medium). Cells were harvested, washed in buffer and homogenized, and protein was measured. Lipid extracts of cell homogenates were used for HPLC; the label distribution in free and acylestrone peaks was measured. Overall uptake of estrone (i.e., the sum of free and acylestrone) by cells was not affected by leptin or corticosterone, but strongly reduced by insulin. Leptin and corticosterone increased the synthesis of acyl-esterone in a dose- and time-dependent way. Insulin decreased acyl-estrone synthesis at low concentrations and with little change over time. The results suggest that control of oleoyl-estrone deposition in adipocytes is modulated in at least two distinct steps: (a) estrone uptake, affected by insulin in the physiological range; and (b) synthesis of oleoyl-estrone from cell estrone. The latter may be affected by insulin, but leptin and corticosterone enhance the process.

Leptin concentrations do not correlate with fat mass nor with metabolic risk factors in morbidly obese females

AIMS

To investigate the determinants of leptinemia in a cohort of morbid obese females compared to those of normal weight and mild-to-moderate obesity, and the relationships between leptin and metabolic derangements associated with obesity.

METHODS

Recruited females were: moderately obese [n=44; body mass index (BMI) 25-40 kg/m2], morbidly obese (n=34; BMI > or = 40 kg/m2) and normal weight volunteers (n=12; BMI 19-25 kg/m2). Fat mass assessed by bioelectrical impedance and fat distribution by waist-to-hip ratio (WHR) were determined in all subjects. Biochemical determinations included plasma leptin, lipoprotein profile, fasting insulin and cortisol.

RESULTS

Plasma leptin values were significantly increased in morbid obese patients (54.95 +/- 1.8 ng/ml) compared to those moderately obese (30.2 +/- 1.7 ng/ml; p<0.001) and to controls (9.77 +/- 1.4 ng/ml; p<0.001). Fat and age-adjusted leptin values were not different between groups. When subjects with a BMI <40 kg/m2 were considered, plasma leptin was significantly and positively related to anthropometric variables (BMI, percentage body fat and WHR), total cholesterol, LDL-cholesterol, plasma triglycerides, AST, ALT and uric acid; and negatively with HDL-cholesterol. In contrast, when morbidly obese patients were analyzed separately, no relationships were observed between leptin concentrations and BMI, percentage of adiposity or biochemical variables. For obese patients no significant differences were observed in the adjusted leptin values with respect to the presence of diabetes, dyslipidemia or hypertension.

CONCLUSIONS

In morbidly obese women, the plasma leptin concentrations, although increased, do not reflect the amount of adipose stores, and as such, factors other than simply adiposity need to be invoked to explain the variation in leptin values.

Anomalous lipoproteins in obese Zucker rats

AIMS

Obesity is characterized by dislipoproteinaemia with increased cholesterol and triacylglycerol levels and lower chylomicra disposal rates. We studied here whether these alterations were related to lipoprotein number and/or size and composition.

METHODS

Plasma from lean and obese Zucker rats was fractionated into lipoprotein classes (chylomicra, very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL)) by differential centrifugation. The apoprotein and lipid composition of each fraction were measured. Lipoprotein particle size was estimated by dynamic light scattering and used to tabulate the mean diameter and volume of lipoprotein micelles. Particle mass was calculated from the density and volume. The mass of lipids and protein in each fraction/ml of plasma allowed the estimation of mean particle concentration and then the number of molecules of lipid and protein/unit of lipoprotein micelle.

RESULTS

A large part of hyperlipidaemia of obese rats is due to the accumulation of chylomicra: 1.3 +/- 0.2 mg/ml in lean rats [LR] (34% of all lipoproteins) and 8.2 +/- 0.9 mg/ml in the obese rats [OR] (66% of all lipoproteins). Lipid percentage composition of lipoproteins was similar in both groups. The particle size of LDL and HDL was much higher in OR than in LR: LDLs weighed 31.1 +/- 7.5 ag (LR) vs. 273 +/- 81 ag (OR), and HDLs weighed 31.7 +/- 12.6 ag (LR) and 375 +/- 103 ag (OR). In chylomicra and VLDL there was a relative scarcity of apoproteins in OR compared with LR. The whole architecture of LDLs is altered in OR, with a predominance of surface lipids: phospholipid and free cholesterol, and lower amounts of core lipids: triacylglycerols and cholesterol esters, with surface/core lipids ratios of 0.74 (LR) and 1.89 (OR). The consequences of anomalous LDL and HDL composition, size and overall structure may result in magnified lipoprotein metabolism alterations that hamper their ability to transfer apolipoproteins to larger chylomicra and VLDL, and to alter cholesterol transfer and binding of their apoproteins to cell surface receptors. The smaller number of LDL and HDL particles may further compound these difficulties and thus change the free to esterified cholesterol ratios observed in OR.

CONCLUSIONS

The main conclusions of this study are the key importance of chylomicron analysis for a better understanding of the transfer of lipids, and the altered lipoprotein size and apoprotein distribution in obese rats, which seriously hamper cholesterol interchange, resulting in hypercholesterolaemia, and thus triggering even more far-reaching consequences for the well-being of the obese.

Lipoprotein lipase and cholesterol transfer activities of lean and obese Zucker rats

Adult female lean and obese Zucker rats maintained under standard conditions were used for the estimation of plasma, liver and white adipose tissue (WAT) activity of lipoprotein lipase, plasma and liver hepatic lipase and plasma lecithin-cholesterol acyltransferase. No differences in plasma or tissue levels of lipoprotein lipase between lean and obese rats were detected, but the larger WAT size of the obese rats resulted in higher lipase activity per unit of rat weight. Hepatic lipase levels in plasma were higher in the obese, but in liver, the higher activity was found in lean rats. No significant differences were found for lecithin-cholesterol acyltransferase activity, except when the levels in the HDL fraction were expressed per unit of protein weight, showing lower activity in the obese rats. In conclusion, the essentially maintained enzyme activities in obese rat tissues suggest that they cannot explain the deficient lipoproteins processing of obese rats, and, consequently their dislipidaemia.

Effect of 24-h food deprivation on lipoprotein composition and oleoyl-estrone content of lean and obese Zucker rats

BACKGROUND

Food deprivation induces the mobilization of fat reserves and, consequently, the transport of lipids in plasma. Zucker obese rats are grossly hyperlipidemic and do not use lipids as an efficient energy substrate. They also have lower circulating levels of acyl-estrone than expected because of their large fat stores.

AIM OF THE STUDY

To measure the effect of 24 h food deprivation on hyperlipidemia and acyl-estrone distribution in plasma in Zucker obese rats.

METHODS

The plasma lipoprotein distribution and composition of Zucker lean (Fa/?) and obese (fa/fa) rats was determined after 24 hours of food deprivation. Lipid classes: phospholipid, free and esterified cholesterol and triacylglycerols, and protein and total (mainly acyl-) estrone were also measured in total plasma and lipoprotein fractions.

RESULTS

Food-deprived rats showed lower triacylglycerol levels than fed rats, but obese rats maintained high lipid levels, mainly in the VLDL fraction. The ratio of total plasma free-to-esterified cholesterol was lower in fed lean rats (0.29) than in the obese (0.61); the situation improved slightly after 24-h starvation, since the corresponding ratios were 0.30 and 0.41. Acyl estrone levels changed little with 24-h food deprivation. The chylomicra + VLDL total estrone compartment was essentially unchanged in lean and obese fed and starved groups, but the HDL pool decreased with food deprivation in the obese.

CONCLUSION

Short-term starvation helped to enhance the differences between lean and obese Zucker rats in the handling of lipoprotein lipids, the latter showing a marked impairment in their ability to dispose of circulating lipids. The different pace of plasma lipid utilization may compound the problems of cholesterol transfer, partly explaining the dyslipemia that characterizes this animal model of obesity. The differences in acyl-estrone distribution also indicate that fat mass is preserved more effectively in obese rats even after food deprivation.

Intestinal handling of an oral oleoyl-estrone gavage by the rat

Adult Zucker lean (Fa/?) female rats received a single 250 nmol oral gavage of 3H-labelled oleoylestrone in 0.2 ml of sunflower oil. After one hour, samples of arterial, portal and suprahepatic blood, and lymph were obtained and fractioned to determine the amount of radioactivity present in the form of free estrone, acyl-estrone and hydrophilic estrone esters in the blood of each vessel. Lipoprotein fractions (chylomicra + VLDL, LDL, HDL and lipoprotein-depleted plasma) were also analysed as well as the distribution of absorbed 3H-estrone in the intestine, specific organs and carcass. About one third of the oleoyl-estrone dose recovered was found in the tissues, mainly in the blood, the rest remaining relatively untouched in the intestinal content. High hypothalamic estrone uptake (compared with the rest of the brain) was observed. Data from non-radioactive estrone measurements showed a similar pattern of absorption and tissue distribution to that obtained by 3H-estrone tracking alone. In both cases, most of the estrone present in the intestinal lumen was absorbed as intact oleoyl-estrone, but a significant part was absorbed as free estrone. There is a net transfer of 3H-estrone into portal blood HDL, and part of the 3H-estrone is also loaded into lymph-carried chylomicra. A large share of free estrone is filtered by the liver, but most of the acyl-estrone absorbed passes unaltered. The oral administration of oleoyl-estrone results in significant absorption of the unaltered molecule, which is transferred to lymph-carried chylomicra and also directly to plasma HDLs. It may be inferred that the HDL fraction contains the physiological carrier of oleoyl-estrone in its role of ponderostat signal.

Oleoyl-estrone does not have direct estrogenic effects on rats

The estrogenic effects of oleoyl-estrone (OE) administration, either though continuous i.v. infusion with osmotic minipumps or administered by daily oral gavage, were studied. Binding of OE to human recombinant purified alpha receptors was negligible, and that of estrone (E1) was only a fraction of 17beta-estradiol (E2) binding. Intravenous--but not oral--OE administration resulted in marked increases of both E1 and E2 in rat plasma, but oral OE did not induce significant changes in either plasma hormone in Wistar or Zucker rats. The weight of uteri and ovaries increased with time of administration in Zucker rats treated with i.v. OE, but inguinal mammary gland proliferation between subcutaneous adipose tissue was even more marked. Oral administration of OE, however, did not increase either uterine weight or mammary gland proliferation, even at doses (10 micromol/kg x d) higher than those given i.v. (3.5 micromol/kg x d). The results indicate that i.v. administration of OE resulted in limited estrogenic effects mainly due to the high accumulation of E1 giving rise to significant increases in E2. On the other hand, oral administration of OE, even at higher daily doses, did not increase the circulating levels of either estrogen and, therefore, there were no significant effects on mammary gland proliferation or uterine weight. The oral administration of OE as a slimming drug, then, do not result in estrogenic side effects over a wide range of daily doses.

Modulation of corticosterone availability to white adipose tissue of lean and obese Zucker rats by corticosteroid-binding globulin

Corticosterone-binding (CB) capacity was determined in periovarian and subcutaneous white adipose tissue (WAT), as well as in plasma of lean and obese Zucker rats. In lean rats, plasma CB was twice the level of obese rats. In lean rat WAT, dexamethasone binding accounted for only 0.05-0.09% of corticosterone binding, and aldosterone bound even less; in the obese rats, dexamethasone accounted for 0.2 - 0.3 % of corticosterone binding. Scatchard plots showed that KD for corticosterone was 3.1 nM (WAT) or 3.4 nM (plasma) in lean rats and 1.8 nM (WAT) or 1.5 nM (plasma) in obese rats. The total CB capacity in WAT was lower in the obese than in lean rats (47-50%). Plasma non-esterified fatty acid levels were higher in obese rats. The results suggest that CBG may limit the access of glucocorticoids to adipocytes more weakly in obese rats because of the lower CBG. Fatty acids may increase the affinity of CBG for corticosterone, which would make WAT cells less accessible to circulating glucocorticoids. The modulation of CBG by fatty acids may protect fat reserves by decreasing the sensitivity of WAT to glucocorticoids.

Oral gavage of oleoyl-oestrone has a stronger effect on body weight in male Zucker obese rats than in female

This study was carried out to determine the effect of sex and oral administration of oleoyl-oestrone on body weight of 12-week-old female and male Zucker obese (fa/fa) rats initially weighing 350-380 g and 405-420 g, respectively. The rats were maintained in standard conditions and given a daily oral gavage of 0.2 ml oleoyl-oestrone dissolved in sunflower oil at a dose of 10 micromol/kg/day for 10 days, and their body weight and food intake was monitored. They were then killed, and their carcass composition (water, lipid, protein and total energy), liver lipids and glycogen and plasma chemistry, insulin, free and total oestrone were measured. Oral administration of oleoyl-oestrone via gavage resulted in significant losses of fat, energy and-ultimately-weight. Treatment with oleoyl-oestrone decreased food intake; the energy expenditure was kept close to that of controls at the expense of internal fat stores. Nevertheless, body protein and plasma metabolite homeostasis were preserved. The slimming effects were more marked in males than in females. Treatment increased circulating acyl-oestrone and reduced to normal levels the high insulin observed in controls. Treatment of genetically obese rats with a daily oral gavage of oleoyl-oestrone resulted in the loss of fat reserves with little modification of other metabolic parameters, except for lower plasma glucose and insulin levels. The results suggest that oleoyl-oestrone, in addition to its slimming effects may be effective as an antidiabetic agent in type 2 diabetes.

Effect of oleoyl-estrone treatment on the expression of beta1- beta2- and beta3-adrenoreceptors in rat adipose tissues

Adult female rats received a constant i.v. infusion of oleoyl-estrone (3.5 pmol/kg day) in a lipidic suspension for 14 days. On days 0 (no treatment), 3, 6, 10 and 14, as well as on day 14 for controls (receiving only the lipid); the rats were killed and the expression of the beta1-, beta2- and beta3-adrenoceptor genes, in brown adipose tissue and in subcutaneous and periovaric white adipose tissue, were measured by RNA protection assay, and compared with that of cyclophyllin. The beta3-adrenoceptor was the most expressed in all adipose tissues, whereas beta2 was the less expressed in brown adipose tissue. Oleoyl-estrone significantly, but moderately, increased the expression of beta-adrenoceptors in the three adipose tissues: beta1 increased in subcutaneous, beta2 and beta3 in periovaric and beta3 in brown adipose tissue. Oleoyl-estrone also decreased beta3 expression in subcutaneous white adipose tissue. On day 10, adipocytes isolated from periovaric white adipose tissue of oleoyl-estrone-treated rats showed higher cAMP response to an isoproterenol challenge than the controls. The mechanism by which oleoyl-estrone elicits the wasting of fat reserves could be mediated by adrenergic pathways, at least in part.

[Hormonal alterations on young morbid obese women]

BACKGROUND

Human obesity is a widespread disease with considerable variability as to its severity, metabolic and endocrine manifestations and etiology. In the present study we have determined whether the alterations of uncomplicated severe obesity in adult young women affect with different intensity the circulating levels of hormones that have been postulated to intervene in the development and maintenance of obesity.

SUBJECTS AND METHOD

Age-matched 20 morbidly obese (BMI 52.6 [8.3 SD] kg/m2) and 10 normal-weight control women (BMI 19.9 [2.1 SD] kg/m2)were studied and determined the basal circulating levels of hormones and proteins related with the control of body weight.

RESULTS

Obese women showed higher concentrations of insulin and leptin, and lower of cortisol and cortisol-binding globulin (CBG). No significant differences were appreciated for free thyroxine, TSH, free and acylestrone and dehydroepiandrosterone-sulphate.

CONCLUSIONS

The results suggest that morbid obesity implies the alteration of the main hormonal systems controlling the availability of energy and the response to external challenges, with the noteworthy exception of the thyroid. There were clear alterations of insulin and leptin,but cortisol changes could be more related to factors other than obesity. The lower than expected levels of acylestrone point to a possible deficit of this ponderostat signal in obese women. The relatively young age of the women in the study may account for the relative shallowness of the hormonal changes observed.

Short-term effects of a hypocaloric diet on nitrogen excretion in morbid obese women

OBJECTIVE

To determine whether the daily pattern of urine excretion of N wastes is affected by obesity and very low-calorie diets (VLCD).

DESIGN

The plasma amino acid, urea and other energy parameters, as well as the urinary excretion of total nitrogen, urea and creatinine were studied in obese and normal-weight women. The obese women's data were obtained under hospital basal controlled conditions (8.1 MJ/day) and after 3 days of VLCD diet (1.9 MJ/day) controls were studied only once (5.8 MJ/day). The hourly excretion patterns of total N, urea and creatinine were determined from the composition of each bladder voiding.

SUBJECTS

Twenty morbidly obese and 10 age-matched normal-weight control women.

RESULTS

Plasma amino acid levels were higher in obese women, which showed a limited ability to metabolize amino acid hydrocarbon skeletons. Neither differences in the patterns between groups nor total 24 h values for urine volume were found. Total N and urea excretion diminished under VLCD diet. Hourly creatinine excretion showed a flat pattern and was higher in obese women than in the controls, VLCD diet diminished the amount of creatinine excreted in 24 h.

CONCLUSIONS

The early change in energy availability that the creatinine excretion figures reflect may result from the energy conservation mechanisms induced in response to energy restriction. The early onset of this effect (3 days, and the extent of decrease (approximately 19%) also suggest that the impact of VLCD on the muscle energy budget of the obese is more marked than usually assumed.

Daily oral oleoyl-estrone gavage induces a dose-dependent loss of fat in Wistar rats

OBJECTIVE

To establish whether single daily oral doses of oleoyl-estrone result in dose-dependent slimming effects on normal weight rats, and to determine the changes in energy parameters induced by this treatment.

RESEARCH METHODS AND PROCEDURES

The effects of a daily oral gavage of oleoyl-estrone (0, 0.2, 0.5, 1, 2, 5, 10, and 20 micromol/kg per day) in 0.2 ml of sunflower oil given over a 10-day period were studied in groups, each of which contained six adult female Wistar rats initially weighing 190 to 230 g. A group of intact control rats receiving no gavage was included for comparison. Body weight and food intake were measured daily. Rats were killed on day 10 of treatment, and body composition (protein nitrogen, lipids, and water), liver lipids, and plasma parameters (glucose, triacylglycerols, total cholesterol, free fatty acids, 3-hydroxybutyrate, urea, aspartate, alanine transaminases, insulin, leptin, and free and acyl-estrone) were measured.

RESULTS

The administration of oleoyl-estrone resulted in a dose-dependent loss of body fat, because of a partly maintained energy expenditure combined with decreased food intake. The differences in the energy budget were met by internal fat pools. The changes recorded did not affect the levels of the main plasma energy homeostasis indicators: unaltered glucose, triacylglycerols, free fatty acids, 3hydroxybutyrate, and urea. Protein was accrued even under conditions of severe lipid store drainage. There were no changes in transaminases. No lipid accumulation was recorded in the liver. Plasma insulin and leptin levels decreased with increased oleoyl-estrone doses, whereas the levels of free and esterified estrone increased with treatment, although not in proportion to the dose received.

DISCUSSION

Oral treatment with oleoyl-estrone resulted in the specific dose-related loss of fat reserves with little change to other metabolic parameters. These results agree with the postulated role of oleoyl-estrone as a ponderostat signal.

Urinary free cortisol excretion pattern in morbid obese women

The urinary excretion of free cortisol in a group of 10 control and 20 morbidly obese women was measured in all bladder voidings during 24 h. The data from obese women were measured under Hospital basal controlled conditions and after 3 days of very low calorie diet (VLCD, 1.9 MJ/d). The hourly cortisol excretion pattern was determined for each woman, and means of each group were computed in order to obtain a 24 h excretion pattern. In controls, the highest excretion rate was in the morning (8-9 h) and the lowest at 21-22 h. Inbasal conditions, the obese showed a similar but flatter pattern; the highest peak was also in the morning (9-10 h), but the lowest rate was between 21 and 24 h. The VLCD diet flattened the pattern even more, in away that no clear peak was observed from the early morning until the afternoon; however, the nadir coincided with that found in basal conditions. These patterns resulted in significant differences between VLCD, basal diet and control. The amount of free cortisol excreted was 93.0 +/- 6.9 nmol/ day in controls, 70.1 +/- 4.7 nmol/day in obese under basal conditions and 62.6 +/- 3.0 nmol/day when subjected to VLCD. The results presented are consistent with a lower overall cortisol secretion in the morbid obese women, which also show a narrower margin of variation in cortisol secretion than non-obese controls. The data also show the significant influence of dietary energy on the pattern of cortisol excretion in obese women.