Prostate tissue and leukocyte levels of n-3 polyunsaturated fatty acids in men with benign prostate hyperplasia or prostate cancer

Nutritional supplementation of the pharmacotherapy of prostate diseases

Introduction: Nutritional supplementation is an integral part of modern pharmacotherapeutic strategies for prostate diseases with different levels of evidence for specific nutrients.

Provitamin A (beta-carotene), vitamin A (retinol) and prostate diseases. Their effects have not been sufficiently studied, and the available data are conflicting to recommend them as a nutritional supplement.

Vitamin E (tocopherol) and prostate diseases. Its effects have not been sufficiently studied, and the available data are conflicting to recommend it as a nutritional supplement.

Vitamin C (ascorbic acid) and prostate diseases. Its effects have not been sufficiently studied, and the available data are conflicted to recommend it as a nutritional supplement.

Vitamin K and prostate diseases. Its effects have not been sufficiently studied, and the available data are conflicted to recommend it as a nutritional supplement.

Vitamin D and prostate diseases. The evidence base of the vitamin D prostatotropic effects has been accumulated, which allows us to consider its deficiency replacement as an effective nutritional supplement in prostate diseases.

Omega-3 PUFAs and prostate diseases. They have universal physiological effects; however, the evidence base for their recommendation as a nutritional supplement for prostate diseases is still insufficient.

Zinc and prostate diseases. Positive effects of zinc on the prostate gland are known for a fact and allow us to recommend it as a nutritional supplement for prostate diseases.

Selenium and prostate diseases. The reliably proven positive effects of selenium on the prostate gland allow us to recommend it as a nutritional supplement for prostate diseases.

Magnesium and prostate diseases. Its effects have not been sufficiently studied, and the available data are conflicting to recommend it as a nutritional supplement.

Racial differences in distribution of fatty acids in prostate cancer and benign prostatic tissues

Background

It remains controversial whether and which fatty acids are different between prostate cancer (PCa) and benign prostatic tissues (BPT) in association with occurrence, progression and racial disparity between African American (AA) and Caucasian American (CA) populations.

Methods

Total fatty acids (TFA) and free fatty acid (FFA) were determined on fresh frozen prostatic tissues including 26 PCa and 21 BPT from AA and CA patients by Gas chromatography with flame ionization detection (GC-FID) and Electrospray Ionization Mass Spectrometry (ESI-MS), respectively.

Results

In all studied population, TFA in 8 out of 16 individual species, in total and in groups of saturated total fatty acid (STFA), mono-unsaturated total fatty acid (MUTFA), poly-unsaturated total fatty acid (PUTFA) and n-6 TFA were significantly higher in PCa than in BPT; FFA in 4 out of 10 individual species, in total and in groups of MUFFA, PUFFA, n-6 FFA and n-3 FFA were significantly higher in PCa than in BPT. The concentrations of most fatty acid parameters correlated with Gleason’s grade and clinical stage of PCa. As compared with CA men, AA men had higher concentrations of TFA, especially TFA with chains of 14–18 carbons than in BPT, and lower concentrations of TFA in PCa.

Conclusions

Increasing in prostatic fatty acids in the form of TFA and FFA correlated to occurrence, progression and racial disparity of PCa.

Combined maternal and post-weaning high fat diet inhibits male offspring's prostate cancer tumorigenesis in transgenic adenocarcinoma of mouse prostate model

BACKGROUND

High fat diet (HFD) and its responsive change of gut microbiota are associated with numerous diseases in human and animal studies. But how maternal and post-weaning HFD may influence the tumorigenesis of prostate cancer (PCa) in male offspring has not yet been reported.

METHODS

We studied both solitary and combined effects of maternal or/and post-weaning HFD on the tumorigenesis of prostate in offspring using a transgenic adenocarcinoma of mouse prostate (TRAMP) model. TRAMP male mice (n = 24) were born to and fostered onto control diet or HFD-fed mothers, the weaned pups were further fed control or fat diet. All mice were sacrificed at the 28th week. The prostate histopathology was performed. The gut microbiota was analyzed by fecal 16S rRNA pyrosequencing, and the serum metabolites were determined by LC-MS/MS.

RESULTS

Our results indicated that post-weaning HFD could significantly promote the PCa tumorigenesis in offspring (P = 0.031), and similar results were found in maternal HFD group but with no significant differences (P = 0.056). However, combined maternal and post-weaning HFD could significantly reduce the PCa tumorigenesis in offspring (P = 0.019). Significant differences in specific microbial populations and serum metabolites were observed across groups. For example, mice with combined maternal and post-weaning HFD had higher abundance of gut Lachonospiraceae, Roseburia, and Amycolatopsis, increased serum L-methionine (P = 0.0052), and decreased serum α-linolenic acid (P < 0.001).

CONCLUSIONS

This study highlights the inhibitory effects of combined maternal and post-weaning HFD on PCa tumorigenesis, and provides new insights into the interactions between diet, gut microbiota, serum metabolites, and PCa.

Influence of metabolic syndrome on the relationship between fatty acids and the selected parameters in men with benign prostatic hyperplasia

The purpose of our investigation was to analyze the relationship between the serum levels of fatty acids and their metabolites and the levels of the selected metabolic and hormonal parameters in patients with benign prostatic hyperplasia (BPH) with regard to concomitant metabolic syndrome (MetS). We determined serum concentrations of total (TT) and free testosterone (FT), insulin (I), dehydroepiandrosterone sulphate (DHEAS), luteinizing hormone and insulin-like growth factor 1 (IGF-1) and sex hormone-binding globulin (SHBG). Gas chromatography was performed. The patients differed in terms of hormone levels, but only the differences in SHBG and IGF-1 levels were statistically significant. Analysis of the levels of polysaturated fatty acids in BPH patients showed that MetS contributed to changes in the levels of these acids. We also analyzed the relationship between the levels of fatty acids and diagnostic parameters for MetS. Particular abnormalities were associated with single changes in the levels of fatty acids. In the diabetic patients, changes in the levels of pentadecanoic acid, heptadecanoic acid and cis-11-eicosenoic acid were demonstrated. Our findings indicate the necessity for further investigation concerning the levels of fatty acids and their impact on the development of MetS, as well as the course and clinical picture of BPH.

Past and Present Insights on Alpha-linolenic Acid and the Omega-3 Fatty Acid Family

Alpha-linolenic acid (ALA) is the parent essential fatty acid of the omega-3 family. This family includes docosahexaenoic acid (DHA), which has been conserved in neural signaling systems in the cephalopods, fish, amphibian, reptiles, birds, mammals, primates, and humans. This extreme conservation, in spite of wide genomic changes of over 500 million years, testifies to the uniqueness of this molecule in the brain and affirms the importance of omega-3 fatty acids. While DHA and its close precursor, eicosapentaenoic acids (EPA), have received much attention by the research community, ALA, as the precursor of both, has been considered of little interest. There are many papers on ALA requirements in experimental animals. Unlike humans, rats and mice can readily convert ALA to EPA and DHA, so it is unclear whether the effect is solely due to the conversion products or to ALA itself. The intrinsic role of ALA has yet to be defined. This paper will discuss both recent and historical findings related to this distinctive group of fatty acids, and will highlight the physiological significance of the omega-3 family.

The therapeutic effects of docosahexaenoic acid on oestrogen/androgen-induced benign prostatic hyperplasia in rats

Benign prostatic hyperplasia (BPH) is one of the major disorders of the urinary system in elderly men. Docosahexaenoic acid (DHA) is the main component of n-3 polyunsaturated fatty acids (n-3 PUFAs) and has nerve protective, anti-inflammatory and tumour-growth inhibitory effects. Here, the therapeutic potential of DHA in treating BPH was investigated. Seal oil effectively prevented the development of prostatic hyperplasia induced by oestradiol/testosterone in a rat model by suppressing the increase of the prostatic index (PI), reducing the thickness of the peri-glandular smooth muscle layer, inhibiting the proliferation of both prostate epithelial and stromal cells, and downregulating the expression of androgen receptor (AR) and oestrogen receptor α (ERα). An in vitro study showed that DHA inhibited the growth of the human prostate stromal cell line WPMY-1 and the epithelial cell line RWPE-1 in a dose- and time-dependent manner. In both cell lines, the DHA arrested the cell cycle in the G2/M phase. In addition, DHA also reduced the expression of ERα and AR in the WPMY-1 and RWPE-1 cells. These results indicate that DHA inhibits the multiplication of prostate stromal and epithelial cells through a mechanism that may involve cell cycle arrest and the downregulation of ERα and AR expression.

Blood level omega-3 Fatty acids as risk determinant molecular biomarker for prostate cancer

Previous researches involving dietary methods have shown conflicting findings. Authors sought to assess the association of prostate cancer risk with blood levels of omega-3 polyunsaturated fatty acids (n-3 PUFA) through a meta-analysis of human epidemiological studies in available online databases (July, 2012). After critical appraisal by two independent reviewers, Newcastle-Ottawa Quality Assessment Scale (NOQAS) was used to grade the studies. Six case control and six nested case control studies were included. Results showed nonsignificant association of overall effect estimates with total or advanced prostate cancer or high-grade tumor. High blood level of alpha-linolenic acid (ALA) had nonsignificant positive association with total prostate cancer risk. High blood level of docosapentaenoic acid (DPA) had significant negative association with total prostate cancer risk. Specific n-3 PUFA in fish oil, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) had positive association with high-grade prostate tumor risk only after adjustment of interstudy variability. There is evidence that high blood level of DPA that is linked with reduced total prostate cancer risk and elevated blood levels of fish oils, EPA, and DHA is associated with high-grade prostate tumor, but careful interpretation is needed due to intricate details involved in prostate carcinogenesis and N-3 PUFA metabolism.

Prostatic alpha-linolenic acid (ALA) is positively associated with aggressive prostate cancer: a relationship which may depend on genetic variation in ALA metabolism

Previous observational studies have reported associations between prostate cancer and alpha-linolenic acid (ALA). However, few investigations have been able to study this relationship prospectively and in well-controlled settings. Moreover, no studies have determined whether single nucleotide polymorphisms (SNPs) that influence ALA metabolism are associated with this common cancer. The purpose of this study was to explore associations between prostatic levels of ALA, SNPs and prostate cancer-specific biomarkers in samples collected from a previous randomized clinical trial conducted using a presurgical model and which tested the effects of flaxseed supplementation, a rich source of ALA, prior to prostatectomy (n = 134). Serum prostate-specific antigen (PSA) was determined and immunohistochemistry was used to assess tumor proliferation rate (Ki67). Prostatic ALA was determined with gas chromatography. Seven previously identified SNPs associated with delta-6 desaturase activity (rs99780, rs174537, rs174545, rs174572, rs498793, rs3834458 and rs968567) were tested for associations with prostatic ALA, PSA and Ki67. Despite consuming seven times more ALA per day, men in the flaxseed arm had similar amounts of prostatic ALA relative to men not consuming flaxseed. In unadjusted analysis, there were significant positive associations between prostatic ALA and PSA (ρ = 0.191, p = 0.028) and Ki67 (ρ = 0.186, p = 0.037). After adjusting for covariates (flaxseed, age, race, BMI and statin-use) the association between ALA and PSA remained (p = 0.004) but was slightly attenuated for Ki67 (p = 0.051). We did not observe associations between any of the SNPs studied and prostatic ALA; however, in models for PSA there was a significant interaction between rs498793 and ALA and for Ki67 there were significant interactions with ALA and rs99780 and rs174545. Independent and inverse associations were observed between rs174572 and Ki67. This study provides evidence that prostatic ALA, independent of the amount of ALA consumed, is positively associated with biomarkers of aggressive prostate cancer and that genetic variation may modify this relationship.

High-fat diet increases NF-κB signaling in the prostate of reporter mice

BACKGROUND

High-fat diet (HFD) is considered as a major risk factor for benign prostatic diseases and cancer in the Western world. Studies have shown an association between oxidative stress and prostatic diseases. NF-κB has been implicated in stress response and is deregulated in prostrate disorders; therefore, we sought to determine whether HFD could induce oxidative stress in the prostate which could contribute to prostatic diseases.

METHODS

Transgenic NF-κB-Luc-Tag mice were either fed with regular diet (RD) or HFD for 12 weeks. Serial, non-invasive molecular imaging was performed to study NF-κB activation in the whole body, and in various organs including thymus, spleen, and prostate. Western blotting was used to determine the expression of NF-κB, its upstream and downstream targets in the prostate.

RESULTS

Twofold increase in whole body NF-κB activity in vivo and two to threefold upregulated prostate NF-κB activity ex vivo were observed after HFD intake compared with RD controls. HFD-induced NF-κB activity was elevated remarkably in the abdominal cavity, thymus, spleen, and prostate with increase in prostrate weight. In the prostrate, an increase in the protein expression of gp91(phox) , p22(phox) , and p47(phox) NADPH oxidase subunits was observed suggesting the involvement of HFD in causing oxidative stress. Nuclear extracts from the prostrate tissue showed an increased expression of p65/RelA that corresponded with elevated cytosolic levels of p-IκBα, along with increased expression of downstream targets of NF-κB, nitric oxide synthase, and cyclooxygenase-2.

CONCLUSIONS

Our findings suggest that HFD-mediated oxidative stress and deregulation of NADPH oxidase leads to NF-κB activation in the prostrate.

Erythrocyte fatty acids and prostate cancer risk: a comparison of methods

The role of fatty acids (FA) in prostate carcinogenesis is unclear. Interest in the inter-relationship among different types of FA has resulted in new analytic approaches to FA and their role in cancer development. We evaluated the association between erythrocyte FA and prostate cancer in 127 prostate cancer patients and 183 screen negative controls. We present three approaches to the analyses of the FA and prostate cancer association; (1) individual or common groups of FA, (2) biologically meaningful FA ratios and (3) principal components analysis. Monounsaturated FA and the alpha-linolenic:eicosapentaenoic ratio were associated with reduced risk of prostate cancer. However, Factor 1, which was strongly correlated with some long chain saturated FA, was associated with an increased risk of prostate cancer. We provide an example of modeling FA and their inter-relationships on the risk of prostate cancer. Comparing three approaches suggests the importance of considering the impact of the entire fatty acid profile in disease prevention.

Detection of polyunsaturated omega-6 fatty acid in human malignant prostate tissue by 1D and 2D high-resolution magic angle spinning NMR spectroscopy

OBJECT

Polyunsaturated omega-6 fatty acids (PUFAs) have been shown to promote prostate cancer. Here, we describe the use of HRMAS NMR spectroscopy to detect omega-6 PUFA species in prostate tissues.

MATERIALS AND METHODS

Samples originating from non-malignant (n = 54) and malignant (n = 27) prostate tissues (from 27 prostatectomized men) were studied by 1D (1)H, 2D (1)H-(1)H and (1)H-(13)C HRMAS NMR spectroscopy followed by histopathological characterization.

RESULTS

HRMAS NMR proved to be a powerful, non-destructive method to identify and characterize PUFAs. The omega-6 PUFA was found in 15% of examined human prostate tumors.

CONCLUSION

It is possible to detect PUFAs in prostate tissues using our NMR-based spectroscopic approach.

Correlations of dietary patterns with prostate health

Both genetic and environmental influences may be involved in etiology of prostate health and prostate cancer. These include ethnic origin, family history, smoking, and diet. Adiposity and excess energy intake are potentially distinct risk factors and positive associations with prostate cancer risk for both were observed among case-control and cohort studies. Some epidemiological studies support an association between dietary fat, particularly saturated or animal fats, and prostate cancer risk. Of these, several suggest reduced risk with low-fat diets high in n-3 fatty acids and increased risk with high-fat diets rich in n-6 fatty acids. Others suggested association with higher meat intake, possibly due to heterocyclic amines and polycyclic aromatic hydrocarbons, produced during grilling or frying. Positive association of prostate cancer risk with dairy intake could involve alpha-methylacyl-CoA racemase activity (required for beta-oxidation of phytanic acid present in dairy products and red meat) or the suppression of vitamin D activity by calcium. Inverse associations were observed with dietary intake of plant foods. These include cereals, soy products, and fruit and vegetable sources of carotenoids. Numerous plant constituents may act synergistically in the prevention and inhibition of prostate disorders. These diet-risk associations may lead to future individualized diet recommendations based upon genetic polymorphisms.

Dietary fatty acids correlate with prostate cancer biopsy grade and volume in Jamaican men

PURPOSE

Jamaica has the highest incidence of prostate cancer in the world. Dietary fat is associated with prostate cancer. The Omega6 polyunsaturated fatty acids have been shown to stimulate prostate carcinogenesis and the Jamaican diet is rich in linoleic acid. We hypothesized positive correlations between Omega6 polyunsaturated fatty acid, prostate specific antigen and prostate biopsy pathology.

MATERIALS AND METHODS

A total of 148 men were enrolled in Kingston, Jamaica. Serum prostate specific antigen and erythrocyte membrane polyunsaturated fatty acids were analyzed. Men with prostate specific antigen 2.6 ng/ml or greater underwent biopsy. Histopathological and statistical analyses were performed on available data.

RESULTS

Of the 54 men who underwent biopsy 24 had prostate cancer, 17 had a Gleason score of 7 or greater and 11 had a tumor volume of 50% or greater. There were significant positive correlations between linoleic acid and Gleason score (p = 0.009), and the linoleic acid-to-docosahexaenoic acid (Omega3) ratio and tumor volume (p = 0.03). There was a significant negative correlation between the arachidonic acid (Omega6)-to-docosapentanoic acid (Omega3) ratio and Gleason score (p = 0.04). Statistical correlations between prostate specific antigen and polyunsaturated fatty acids were inconsistent.

CONCLUSIONS

The positive correlations between linoleic acid and Gleason score, and the linoleic acid-to-docosahexaenoic acid ratio and tumor volume support studies showing that Omega6 polyunsaturated fatty acids stimulate and Omega3 polyunsaturated fatty acids inhibit prostate cancer growth. The negative correlation between the arachidonic acid-to-docosapentanoic acid ratio and Gleason score supports studies that demonstrate increased metabolism of arachidonic acid in prostate cancer to form carcinogenic metabolites, namely prostaglandin E2. Our findings support the association between dietary fatty acids and prostate cancer, and they warrant further dietary and tissue studies in high risk populations.