Calcium deficiency modifies polyunsaturated fatty acid metabolism in growing rats

Existing knowledge on Zn status biomarkers (1963-2021) with a particular focus on FADS1 and FADS2 diagnostic performance and recommendations for further research

The role of Zn in human health was discovered 60 years ago, and despite remarkable research efforts, a sufficiently sensitive and specific biomarker of Zn status is still lacking. Plasma/serum Zn, currently the best available and most accepted population Zn status indicator, responds well to severe Zn deficiency, yet, mild to moderate Zn deficiency states usually remain unrecognized. Identifying early-stage Zn deficiency requires additional robust markers of Zn status. This paper discusses the sensitivity, specificity, and responsiveness of plasma Zn concentrations to Zn interventions. It describes the biochemical and dietary basis for the causal association between Zn and fatty acid desaturases activity, FADS1 and FADS2, based on data collected through studies performed in animals and/or humans. The influence of potential confounders and covariates on the observed relationships is considered. Additional potential Zn biomarkers are discussed and suggestions for further research in this area are provided.

Potential role of neglected and underutilized plant species in improving women's empowerment and nutrition in areas of sub-Saharan Africa

In the context of the nutrition transition, women in sub-Sahara Africa are a critical target group from a nutrition standpoint, and they experience significant discrimination in food production. Food-based, women-centered strategies are recommended to address nutrient gaps, and to educate and empower women. In this context, local natural resources, such as neglected and underutilized plant species (NUS), may contribute to adding nutritional value, enriching diet diversity, and ensuring nutrition security. The aim of the current narrative review is to investigate the nutritional status of the sub-Saharan African population and the potential role of local agriculture strategies in improving food production and diet diversity and in expanding income-generating activities for women. The nutritional properties of the most important regional NUS are also discussed.

Peripheral markers in neurodegenerative patients and their first-degree relatives

We have determined various biomarkers in the peripheral blood of Alzheimer, Parkinson and vascular dementia patients by comparing the samples with those of first-degree relatives and control subjects. Our results, together with correlation studies using data from the Mini-Mental State Examination (MMSE), suggest that the clinical evaluation of the nitrite (NOx) concentration in Alzheimer patients should be complemented by assays of protein carbonyls (PCs) levels, the ratio of reduced to oxidized glutathione (GSH/GSSG) in plasma, PCs in erythrocytes and PCs and calcium content in leukocytes. For Parkinson patients it would be useful to determine NOx, thiobarbituric-acid reactive substances (TBARS) and PCs in erythrocytes, and NOx and TBARS en leukocytes. For vascular-demented (VD) patients, determination of NOx, Cu, and GSH/GSSG in plasma and TBARS, and PCs in erythrocytes together with PCs in leukocytes should be assayed. Relatives of Alzheimer patients showed alterations in plasma Se and Zn concentrations, catalase (CAT) activity in erythrocytes and calcium content in leukocytes as possible predictive markers of the disease. Relatives of Parkinson patients showed elevated levels of NOx in leukocytes. In the case of vascular-demented patients we suggest NOx, GSH/GSSG and α-tocopherol in plasma, the CAT/superoxide dismutase ratio in erythrocytes and TBARS, GSSG and glutathione reductase in leukocytes as predictive markers. Large-scale longitudinal population-based studies using these suggested biomarkers are necessary in order to assess their level of reliability and specificity in clinical practice.

Alpha-tocopherol protects against oxidative damage to lipids of the rod outer segments of the equine retina

Oxidative stress is a possible risk factor for eye diseases. Lipid peroxidation is one of the major events induced by oxidative stress and is particularly active in polyunsaturated fatty acid (PUFA)-rich biomembranes. This work evaluated endogenous lipid antioxidants, in vitro non-enzymatic lipid peroxidation of rod outer segment membranes (ROS), the fatty acid composition during oxidative damage of total lipids from equine retina and ROS, and the protective action of alpha-tocopherol (alpha-Toc). The major lipid soluble antioxidant was alpha-Toc followed by retinoids and carotenoids. The retina contained a high percentage of PUFAs, mainly docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6). Lipid peroxidation of the equine ROS, induced by Fe(2+)-ascorbate, was monitored using chemiluminescence (CL) with or without pre-treatment with alpha-Toc. With alpha-Toc pre-treatment, CL values were significantly decreased. The most abundant fatty acid was 22:6n-3. After 3h incubation, 95% of total PUFAs were destroyed by peroxidation, whereas in alpha-Toc pre-treated ROS the percentage was significantly decreased. The results show that the retina has an endogenous lipid soluble antioxidant system. ROS were highly sensitive to oxidative damage, since their fatty acid composition was markedly modified during the lipid peroxidation process. The protective role of alpha-Toc as an antioxidant was evident and it could be used in the treatment of equine ocular diseases in which free radicals are involved.

A reliable biomarker derived from plasmalogens to evaluate malignancy and metastatic capacity of human cancers

Antigen tumor markers employed in monitoring therapeutical approaches are limited by their specificity (Sp) and sensitivity (Se). The aim of this study was to investigate the suitability of a lipid tumor marker derived from ether-linked phospholipids and to compare it with others usually assayed in clinical practice. Complex lipids from normal and pathological breast, lung, and prostate tissue were isolated and analyzed by TLC and c-GLC methods. Results were compared as pooled samples, or by means of the averaged percent changes with respect to the composition observed in the normal tissue of the same patient. Sp, Se, negative-predictive (NPV) and positive- predictive values (PPV) were established for conventional markers and for the proposed lipid-derived marker. Results demonstrated that the content of monoenoic fatty acyl chains was significantly increased in total lipids, phosphatidylethanolamine, and especially in ethanolamine-containing ether lipids of neoplastic tissues with respect to their corresponding normal ones. Major changes were observed in the plasmalogen sub-fraction where the ratio monoenoic/saturated fatty acids can distinguish with high Se normal tissues from either benign or neoplastic tissues from breast, lung, or prostate lesions. Analyses of fatty acyl chains from ethanolamine-containing plasmalogens provided a reliable tumor marker that correlated with high Se and linearity with metastases spreading. This fact may be useful in prognosis of the most frequently observed human cancers.

Lipid Metabolism in Rats is Modified by Nitric Oxide Availability Through a Ca++-Dependent Mechanism

We studied lipid metabolism and the antioxidant defense system in plasma and liver of rats fed diets supplemented with L(omega)-nitro-L-arginine methyl ester (L-NAME), isosorbide dinitrate (DIS), L-arginine (Arg), or the associations of these drugs. Liver hydroperoxide and thiobarbituric-acid-reactive substance (TBARS) levels were decreased by Arg and increased by L-NAME or DIS treatments. Oxidized glutathione and conjugated dienes were increased by DIS. Nitrate + nitrite levels and serum calcium ([Ca(++)]) were incremented by Arg or DIS and reduced by L-NAME. Superoxide dismutase and catalase activities decreased under Arg treatment, while L-NAME or DIS caused stimulation. Liver high-density lipoprotein (HDL) cholesterol was increased by DIS or NAME (alone or associated with Arg). Free fatty acids and neutral and polar lipids were increased by Arg, L: -NAME, and DIS. However, predominating phospholipid synthesis increased the neutral/polar ratio. Decreased levels of nitric oxide (NO) (low [Ca(++)]) was directly associated with increased fatty acid synthetase, decreased phospholipase A(2), carnitine-palmitoyl transferase, and fatty acid desaturase activities. Raised NO (high [Ca(++)]) inversely correlated with increased phospholipase-A(2) and acyl-coenzyme A (CoA) synthetase and decreased fatty acid synthetase and beta-oxidation rate. Arg or DIS produced changes that were partially reverted by association with L-NAME. Based on these observations, prolonged therapeutical approaches using drugs that modify NO availability should be carefully considered.

Bone morphology, strength and density are compromised in iron-deficient rats and exacerbated by calcium restriction

Rats fed an iron-deficient diet develop decreased bone mass and increased fragility. This study documents that rats fed two minerals likely to be low in American diets, calcium and iron, had dramatic changes in bone density and morphometry. Weanling male Long-Evans rats were fed a diet that was either deficient in iron (5-8 mg/kg or 89-143 micro mol/kg diet), low in calcium (1.0 g/kg Ca or 0.025 mol/kg diet) or deficient in both minerals or a control diet with adequate iron and calcium. Eight rats in each of the four groups were fed their respective diets for 5 wk. Total femur and tibia widths were decreased in all experimental groups and iron-deficient rats had decreased medullary widths compared with the other three groups. Cortical width was decreased in all experimental groups, with either the calcium-restricted group or the iron-deficient + calcium-restricted group showing the greatest impact. Both calcium restriction and iron deficiency, either singly or in combination with one another, had reduced cortical bone area. Analysis by dual-energy X-ray absorptiometry revealed a pattern of significant reductions in bone density for iron-deficient, calcium-restricted and the combination of calcium-restricted+ iron-deficient rats, respectively, as compared with controls. These data suggest that a commonly deficient trace element in American diets, iron, has a negative impact upon bone health, and this impact is exacerbated by a calcium-restricted diet.

Correlation between fatty acyl composition in neutral and polar lipids and enzyme activities from various tissues of calcium-deficient rats

In this study we investigated the changes induced by feeding rats a calcium-deficient diet (0.5 g Ca/kg diet) during 65 d after weaning. Phospholipase A2, acyl-Co synthetase and FA delta9-, delta6-, and delta5-desaturase activities were also determined. Calcium deficiency evoked a general alteration in the quality and proportion of the FA chains acylated to neutral and polar lipids from liver, lungs, spleen, brain, kidneys, fat, articular cartilage, erythrocyte ghosts, and plasmas, characterized by an increment of saturated FA and a significant depletion of polyunsaturated acids derived from linoleate and alpha-linolenate. Several interlipid and lipid/protein relationships were also modified in microsomes from calcium-deprived rats, with a concomitant reduction in the rotational mobility of the probe diphenylhexatriene. Phospholipase A2 and acyl-CoA synthetase activities were also decreased and increased, respectively, in some tissues from calcium-deficient rats, whereas delta9-, delta6- and delta5-desaturases were significantly depressed. We conclude that changes in tissue fatty acyl composition evoked by calcium deprivation are due to alterations in the acylation/deacylation cycles via inhibition of the phospholipase A2. These changes were reflected in the physicochemical properties of the membranes, which in turn inhibits desaturase activities. A possible failure in the transcriptional rate for desaturase-mRNA was also discussed.

Relevance of apolipoproteins in the development of fatty liver and fatty liver-related peripartum diseases in dairy cows

Most metabolic diseases in dairy cows occur during the peripartum period and are suggested to be derived from fatty liver initially developed during the nonlactating stage. Fatty liver is induced by hepatic uptake of nonesterified fatty acids that are released in excess by adipose tissues attributable to negative energy balance. The fatty accumulation leads to impairment of lipoprotein metabolism in the liver, and the impairment in turn influences other metabolic pathways in extrahepatic tissues such as the steroid hormone production by the corpus luteum. Detailed understanding of the impaired lipoprotein metabolism is crucial for elucidation of the mechanistic bases of the development of fatty liver and fatty liver-related peripartum diseases. This review summarizes results on evaluation of lipoprotein lipid and protein concentrations and enzyme activity in cows with fatty liver and those with ketosis, left displacement of the abomasum, milk fever, downer syndrome and retained placenta. Obtained data strongly suggest that decreases in serum concentrations of apolipoprotein B-100, apolipoprotein A-I and apolipoprotein C-III, a reduction in activity of lecithin:cholesterol acyltransferase and induction of haptoglobin and serum amyloid A are intimately related to the development of fatty liver and fatty liver-related diseases. Moreover, determination of the apolipoprotein concentrations and enzyme activity during the peripartum period is useful for early diagnoses of these diseases.