The pathology of essential fatty acid deficiency: is it cell adhesion mediated?

Proposition of a New POLA Index to Assess the Immunomodulatory Properties of the Diet and Its Relationship with the Gut Microbiota, Using the Example of the Incidence of COVID-19 in a Group of People without Comorbidities

A rise in the incidence of infections with severe acute respiratory syndrome coronavirus 2 has sparked the search for protective strategies against the new pathogen. It is known that individual food components can interact with different immune cells, modulating the immune response of the body. The aim of this study was to develop an index assessing the immunomodulatory potential of diet (POLA index) and to test its utility for the prediction of coronavirus disease 2019 (COVID-19) in a group of healthy young people following a traditional or vegetarian diet. Data on body composition, anthropometric measurements, physical activity, dietary intake, and gut microbiota were obtained from 95 adults (mean age, 34.66 ± 5.76 years). There was a strong correlation between the dietary inflammatory index and the POLA index (r = 0.90; p < 0.0001). Based on Cohen’s kappa statistic, there was a good agreement in qualitative interpretation between the two indices (kappa = 0.61; p < 0.0001). People on a diet with beneficial immunomodulatory effects had a lower risk of COVID-19 of approximately 80%, as compared with those on a diet with highly unbeneficial immunomodulatory effects. In daily practice, the POLA index might serve as a useful tool for dietitians to identify individuals whose diet is deficient in ingredients for optimal immune system function and change their dietary behavior to ensure optimal immune function that reduces the risk of infection.

Linoleic Acid Inhibits the Release of Leishmania donovani Derived Microvesicles and Decreases Its Survival in Macrophages

Visceral leishmaniasis is a neglected tropical disease caused by Leishmania (L.) donovani parasite in the Indian subcontinent. Macrophages (mϕ) are the harboring cells for parasite and their interactions dictate the pathogenesis of this disease. Polyunsaturated fatty acids are an integral part of the mϕ cell membrane and are derived from linoleic acid (LA), which is a principal essential fatty acid. Here, we have investigated the effect of the simultaneous presence of LA during L. donovani infection in mϕ. Treatment with LA suppresses the parasitic load in mϕ (kDNA expression) and promotes the Th-1 type immune response (IL-12, iNOS). However, no significant change in kDNA expressions was observed when L. donovani promastigotes were treated with LA. Intrigued by this observation, we explored mechanism(s) by which LA promoted the protective type immune response in infected mϕ. Interestingly, LA decreased the release of L. donovani derived extracellular vesicle later characterized as microvesicles. Moreover, these microvesicles were suppressive concerning their bias toward the Th-2 type of immune responses (IL-10, Arginase) in mϕ. We suggest that LA plays a protective role in the immune response against L. donovani infection by inhibiting the release to Leishmania derived microvesicles and thus promoting Th-1 type immune response in mϕ.

Preventive as well as therapeutic significances of linoleic acid in the containment of Leishmania donovani infection

People suffering from malnutrition show compromised levels of ω-6 fatty acid and malnutrition is frequently observed among visceral leishmaniasis (VL) patients as disease inflicts primarily the socioeconomic destitute communities. Dietary linoleic acid (LA, 18:2; ω-6 fatty acid) is the principal source of essential fatty acid and its derivatives i.e. eicosanoids possess immune-modulatory activities. However, its role in VL is not yet established. LA was measured in VL human subjects (serum) as well as in Leishmania(L.)donovani infected hamsters (serum and visceral organs). Organ-specific mRNA expressions of various enzymes of the LA metabolic pathway were measured in visceral organs of infected hamsters. Our findings showed a decrease in the concentrations of LA in the serum samples of VL patients, suggesting malnutrition among these patients. However, in L. donovani infected hamsters, its level was not altered in the early infection (15 days) and then increased at late infection (60 days). Importantly, the supplementation of LA restored the Th-1 type of immune response and significantly reduced the parasite load within infected macrophages in vitro. This protective response of LA was mediated through 5-lipoxygenase pathway not via the cyclooxygenase pathway. Preventive usage of LA to mϕ followed by L. donovani infection also showed the strengthening of Th-1 immune response and significantly fewer parasite loads. Our findings demonstrate the protective role of LA in the containment of the parasite load. Incorporating LA rich oils in daily food habits across highly inflicted regions may be a significant advancement towards the eradication of the disease.

Role of ω3 polyunsaturated fatty acids in diabetic retinopathy: a morphological and metabolically cross talk among blood retina barriers damage, autoimmunity and chronic inflammation

Vision disorders are one of the most serious complications of diabetes mellitus (DM) affecting the quality of life of patients and eventually cause blindness. The ocular lesions in diabetes mellitus are located mainly in the blood vessels and retina layers. Different retina lesions could be grouped under the umbrella term of diabetic retinopathies (DMRP).

We propose that one of the main causes in the etiopathogenesis of the DMRP consists of a progressive loss of the selective permeability of blood retinal barriers (BRB). The loss of selective permeability of blood retinal barriers will cause a progressive autoimmune process. Prolonged autoimmune injures in the retinal territory will triggers and maintains a low-grade chronic inflammation process, microvascular alterations, glial proliferation and subsequent fibrosis and worse, progressive apoptosis of the photoreceptor neurons.

Patients with long-standing DM disturbances in retinal BRBs suffer of alterations in the enzymatic pathways of polyunsaturated fatty acids (PUFAs), increase release of free radicals and pro-inflammatory molecules and subsequently incremented levels of vascular endothelial growth factor. These facts can produce retinal edema and photoreceptor apoptosis.

Experimental, clinical and epidemiological evidences showing that adequate metabolic and alimentary controls and constant practices of healthy life may avoid, retard or make less severe the appearance of DMRP. Considering the high demand for PUFAs ω3 by photoreceptor complexes of the retina, it seems advisable to take fish oil supplements (2 g per day). The cellular, subcellular and molecular basis of the propositions exposed above is developed in this article.

Synthesizer drawings the most relevant findings of the ultrastructural pathology, as well as the main metabolic pathways of the PUFAs involved in balance and disbalanced conditions are provided.

Crosstalk among dietary polyunsaturated fatty acids, urolithiasis, chronic inflammation, and urinary tract tumor risk

Based on a consistent bulk of experimental and epidemiologic works, we proposed that abnormal metabolism and/or dietary deprivation of essential polyunsaturated fatty acids by inducing a chronic and subclinical essential fatty acid deficiency (EFAD) in urothelial cell membranes may enhance the risk for urinary tract tumor (UTT) development. This threat may be enhanced by the unusual fact that the fatty-acid profile of the normal urothelium is similar to that reported in EFAD. The risk for UTT may be worsened when coexisting with a low-grade chronic inflammation (LGCI) state induced by urolithiasis or disbalance management of peroxides, free radical molecules, and their quenchers. There is cumulative evidence linking the LGCI of the urinary tract mucosa, calculi, and UTT, due to the long-standing release of promitotic, promutagen, and pro-inflammatory antiapoptotic cytokines in these conditions. The dual role played by pro- and anti-inflammatory eicosanoids and bioactive lipids, cytokines, and the disbalance of lipid peroxidation is discussed, concluding that the moderate, long-standing consumption or dietary supplementation of ω-3 PUFAs may improve the chances of avoiding UTT development.

Abnormal fatty acid pattern in intestinal mucosa of children with celiac disease is not reflected in serum phospholipids

OBJECTIVE

Celiac disease (CD) is characterized by chronic inflammation of the small intestinal mucosa with disturbed epithelial transport. The fatty acid (FA) composition of intestinal membranes is important for epithelial function, and disturbances may contribute to the pathophysiology of the disease. We aimed to evaluate whether the intestinal mucosal FA status was reflected in serum phospholipids of patients with CD.

PATIENTS AND METHODS

Samples were obtained from 7 pediatric patients with active CD showing mucosal atrophy, 6 pediatric patients with CD in remission, and 11 control pediatric patients with morphologically healthy intestinal mucosa. Small intestinal biopsies were obtained using a Watson biopsy capsule under fluoroscopic control. Blood samples were collected on the same morning after an overnight fast. Tissue phospholipids were isolated by high-performance liquid chromatography, and FAs were analyzed by capillary gas-liquid chromatography.

RESULTS

Serum phospholipid FA showed marginal differences between the patients with CD and the controls. Significant differences were observed in mucosa with active CD compared with controls. Linoleic acid (18:2n-6) level was decreased, whereas those of its derivatives were elevated, indicating increased transformation of n-6 FA. Mead acid (20:3n-9) level was increased, with an increased ratio of Mead acid to arachidonic acid (20:4n-6) levels, suggesting essential fatty acid deficiency. The n-3 FA levels were not significantly changed. During remission, the FA pattern of the intestinal mucosa was mainly similar to that in controls.

CONCLUSIONS

The FA abnormality of intestinal mucosa in patients with active CD was not reflected in serum values. Altered FA content may contribute to the pathophysiology of the disease because FAs are important for enzymes and for the transport and receptor functions of epithelial membranes.

Mechanisms of lipid malabsorption in Cystic Fibrosis: the impact of essential fatty acids deficiency

Transport mechanisms, whereby alimentary lipids are digested and packaged into small emulsion particles that enter intestinal cells to be translocated to the plasma in the form of chylomicrons, are impaired in cystic fibrosis. The purpose of this paper is to focus on defects that are related to intraluminal and intracellular events in this life-limiting genetic disorder. Specific evidence is presented to highlight the relationship between fat malabsorption and essential fatty acid deficiency commonly found in patients with cystic fibrosis that are often related to the genotype. Given the interdependency of pulmonary disease, pancreatic insufficiency and nutritional status, greater attention should be paid to the optimal correction of fat malabsorption and essential fatty acid deficiency in order to improve the quality of life and extend the life span of patients with cystic fibrosis.

The possible role of essential fatty acids in the pathophysiology of malnutrition: a review

Biochemical evidence of essential fatty acid deficiency (EFAD) may exist in protein-energy malnutrition (PEM). EFAD is characterised by low 18:2omega6, often in combination with low 20:4omega6 and 22:6omega3, and high 18:1omega9 and 20:3omega9. Some PEM symptoms, notably skin changes, impaired resistance to infections, impaired growth rate and disturbed development may at least partly be explained by EFAD. One or more of the following factors could induce EFAD in PEM: low EFA intake, poor lipid digestion, absorption, transport, desaturation and increased EFA beta-oxidation and peroxidation. EFAD may perpetuate itself by decreasing lipid absorption and transport, and aggravate PEM by impairing nutrient absorption and dietary calorie utilisation. Micronutrient deficiencies may contribute to the impaired EFA bioavailability and metabolism. Nutritional rehabilitation strategies in PEM may consider adequate intakes of EFA and micronutrients, e.g. by promoting breastfeeding. More research is required to gain detailed insight into the role of EFAD in PEM.

Effects of eicosatrienoic acid (20:3 n-9, Mead's acid) on some promalignant-related properties of three human cancer cell lines

The essential fatty acid deficiency (EFAD) is a metabolic condition related to cancer development. We studied the effect of eicosapentaenoic acid (EPA, 20:5 n-3) and eicosatrienoic acid (ETA, 20:3 n-9), an essential fatty acid (EFA) and non-EFA respectively, on tumour cells parameters linked to tumour progression and metastases. Human tumour cell lines (T-24 from urothelium, MCF-7 from breast and HRT-18 from colon) were used. EPA showed an anti-proliferative effect on the three lines. ETA showed the following effects: in T-24, the lipid peroxidation was decreased and E-cadherin was undetectable; in MCF-7, increased E-cadherin expression enhanced the lipid peroxidation and decreased cell proliferation; on HRT-18, the E-cadherin expression and lipid peroxidation diminished, whereas cell proliferation was increased. In conclusion, EFA (20:5 n-3) exhibited beneficial effects, whereas unusual ETA showed an opposite effect on some tumour parameters. The possible riskiness of EFA-deprivation, along with the potential of EFA as natural nutrapeutic products for human tumour prevention and treatment, makes EFA worthy of further consideration.

Cellular basis and clinical implications of biological markers in salivary tissues: their topological distribution in murine submandibular gland

Cell proliferation and apoptosis as well as cell-cell adhesion and communication are essential processes that assure cell survival, renewal and coordination. Since junctional proteins have a tumor suppressor activity, their immunohistochemical characterization has diagnostic and prognostic value. The purpose of this report is to review the role played by junctional and proliferation-related proteins in the salivary glands and to illustrate their immunohistochemical localisation in normal murine submandibular gland. Normal salivary gland tissue was obtained from normal adult male BALB/c mice. After immediate fixation in formalin and ethanol, the samples were immunohistochemically stained for E-cadherin (HECD-1), Bcl-2, Ki67 (MIB-1), connexin26 and connexin 32, beta-catenin and gamma-catenin. Their topological distribution and reactivity were evaluated by light microscopy. The nuclei of submandibular acinar cells exhibited low to moderate staining for Ki67, but no reaction was observed in ductal cells. Murine Bcl-2 was light to moderately expressed in the latero-basal domain of cells of submandibular acini but was only lightly expressed in striated and eosinophilic ducts. The lateral domain of acinar cells were heavily stained with anti-E-cadherin, while only low levels were expressed at the cellular surface of ducts. beta-Catenin was consistently and evenly distributed along the latero-apical boundaries of eosinophilic secretory duct cells as well as on the lateral domain of acinar cells. On the contrary, gamma-catenin was generally expressed at lower levels than beta-catenin, was not expressed in ductal cells and was only lightly stained on the lateral membranes of acinar cells. No expression of connexin 32 was observed in ducts but it was significantly expressed in a spotted pattern along the plasma membrane of acinic cells. Connexin 26 showed similar localization to that of connexin 32 but the staining was much more intense. Since these proteins have been reported to play key roles in maintaining homeostasis via control of cell growth, differentiation and death, their analysis in normal salivary tissue will hopefully contribute to the study of salivary tumorigenesis.

Dietary polyunsatured fatty acids (PUFA) differentially modulate melamine-induced preneoplastic urothelial proliferation and apoptosis in mice

A number of experimental and epidemiological studies indicate that dietary polyunsaturated fatty acids (PUFA) play a modulatory role in the development of several cancers. However, literature on the importance of dietary PUFA in urinary-tract tumourigenesis is scarce, and even contradictory. Therefore, our purpose was to evaluate comparatively, several urothelial cellular parameters linked to neoplasia when 180 BALB/c mice were initiated with the tumourigenic agent melamine and fed with two amounts of different PUFA. In experiment 1, mice were fed with 6% of fish oil (enriched in n-3 PUFA, FO), corn oil (enriched in n-6, CO) and olein (enriched in n-9, an EFA deficiency inducer) formulae plus two chow-fed control lots with (CM) and without (C) melamine treatment. In experiment 2, each of the three varieties of PUFA were offered at 10%. Following 18-22 weeks of melamine treatment, animals were autopsied. The liver fatty acid profile showed a close correlation with the dietary sources, exhibiting in the O group macroscopic and biochemical EFA-deficient (EFAD) characteristics. The frequency of simple urothelial hyperplasias (H) and dysplasia/carcinoma in situ (D/CIS) was significantly lower in the FO group, whereas both types of lesions increased in the CO and O groups, compared to the C and CM mice. Increased proliferation and abnormal luminal localized mitosis were more frequently recorded in EFAD mice, whereas abnormal apoptotic/mitosis ratio increased in both olein- and corn-oil-fed animals. This study shows that dietary PUFA modulate differentially normal and pre-neoplastic proliferation when induced by the tumorigenic agent melamine. Fish oil, rich in n-3 fatty acids, exhibits a clear antipromoting activity, whereas the role of n-6 and n-9 PUFA derivatives needs further research.