The effect of conjugated linoleic acids on inflammation, oxidative stress, body composition and physical performance: a comprehensive review of putative molecular mechanisms

Portulaca oleracea L seed extracts counteract diabetic nephropathy through SDF-1/IL10/PPARγ-mediated tuning of keap1/Nrf2 and NF-κB transcription in Sprague Dawley rats

BACKGROUND & OBJECTIVE

While oxidative stress is the key player driving diabetic nephropathy (DN), firm glycemic control remains the pillar prophylactic measure. Purslane was extensively described as a potent hypoglycemic and hypolipidemic agent owing to its rich content of antioxidants. Therefore, this report aimed to assess the renoprotective potentials of methanol (MO) and methylene chloride (MC) fixed oil extracts of purslane seeds in a diabetic nephropathy (DN) model.

METHODS

Purslane seeds were extracted using absolute methanol and methylene chloride, and type-1 diabetes was induced with a single 55 mg/kg dose of Streptozotocin (STZ) dissolved in 100 mmol/L citrate buffer (pH 4.5), and then diabetic animals were received MO, MC, for 42 consecutive days to compare their antidiabetic effect relative to the reference drug "Losartan". Renal functions and DN biomarkers were weekly assessed, and the relative expression of different oxido-inflammatory mediators was quantified in diabetic kidneys by RT-PCR. Data were statistically analyzed using GraphPad Prism 9.0.2.

RESULTS

The oral administration of MO and MC extracts (250 mg/kg/day) significantly ameliorated the body weight loss (P < 0.0001 / each), fasting blood glucose levels (FBG) (P < 0.0001 / each), urine volume (P < 0.0001 / each), as well as serum creatinine (P < 0.0001 / each), uric acid (P = 0.0022, 0.0052), and blood urea nitrogen (BUN) (P = 0.0265, 0.0338); respectively, compared with the untreated diabetic rats. In addition, both extracts restored the effectuality of antioxidative machinery in diabetic kidneys as indicated by a significant reduction of ROS accumulation and lipid peroxidation; higher GSH content, and promoted activity of glutathione reductase and superoxide dismutase antioxidant enzymes (P < 0.0001 / each). Histologically, both extracts alleviated the DN-structural alterations including the glomerular congestion and tubular degeneration, with MC-treated kidneys showing near to normal architecture. The transcription profiles of all treated kidneys revealed a significantly downregulated expression of TNF-α, IL-6, Keap1 and NF-κB genes, concomitant with a significant upregulation of SDF-1, IL-10, Nrf2, HO-1, and PPARγ gene expression (P < 0.0001 / all).

CONCLUSION

These findings highlight the remarkable DN-prophylactic potentials of purslane extracts mediated by neutralizing the hyperglycemia-induced ROS accumulation, and circumventing the downstream inflammatory cascades, surpassing the reference angiotensin receptor blocker; i.e. Losartan.

Effects of Cranberry Extract (Vaccinium macrocarpon) Supplementation on Lipid Peroxidation and Inflammation in Patients with Chronic Kidney Disease (Stages 3-4): A Randomized Controlled Trial

Background

Growing evidence suggests that bioactive compounds in berry fruits may mitigate inflammation in patients with chronic kidney disease (CKD).

Objectives

To evaluate cranberry (Vaccinium macrocarpon) supplementation effects on modulation of transcription factors involved in inflammation and oxidative stress in nondialysis (stages 3 and 4) patients with CKD. Design/Participants. A randomized, double-blind, placebo-controlled study was performed with 30 patients to receive capsules containing cranberry extract (1000 mg/day) or placebo (1000 mg/day of corn starch) for two months. Measurements. The mRNA expression of nuclear factor-erythroid 2-related factor-2 (Nrf2) and nuclear factor-kB (NF-kB) was evaluated in peripheral blood mononuclear cells (PBMCs) by quantitative real-time polymerase chain reaction. Thiobarbituric acid reactive substances (TBARS) were measured in the plasma to assess oxidative stress. Interleukin-6 (IL-6) plasma levels were assessed by enzyme-linked immunosorbent assay and C-reactive protein (CRP) by immunoturbidimetric method.

Results

Twenty-five patients completed the study: 12 in the cranberry group (56.7 ± 7.5 years and body mass index (BMI) of 29.6 ± 5.5 kg/m2) and 13 in the placebo group (58.8 ± 5.1 years and BMI 29.8 ± 5.4 kg/m2). There were no differences in NF-kB or Nrf2 mRNA expressions (p = 0.99 and p = 0.89) or TBARS, CRP, and IL-6 plasma levels after cranberry supplementation.

Conclusions

The cranberry extract administration (1000 mg/day) did not affect Nrf2 and NF-kB mRNA expression, oxidative stress, or inflammatory markers levels in nondialysis CKD patients. This trial is registered with NCT04377919.

Arachidonic acid level is related to early motor recovery following intracerebral hemorrhage with severe motor paralysis

BACKGROUND

Low arachidonic acid (AA) levels are reportedly associated with unfavorable outcomes in intracerebral hemorrhage (ICH).

OBJECTIVE

We aimed to clarify whether serum AA levels might be associated with a good recovery from severe motor paralysis in the early stage of hospitalization.

METHODS

From among consecutive ICH patients between October 2012 and December 2021, patients with a sum of upper and lower extremity National Institutes of Health stroke scale (NIHSS) scores of 4-8 at admission (severe motor paralysis) were included. We defined good early recovery from severe motor paralysis as a sum of upper and lower extremity NIHSS scores of 0-3 on day 7 after admission, and that of individual upper and lower extremities as NIHSS scores of 0-1 on day 7 after admission. We aimed to assess whether serum AA levels might be associated with good early recovery from severe motor paralysis.

RESULTS

We screened 377 consecutive ICH patients, including 140 with severe motor paralysis (88 (63%) males, median age 64 years). Recovery from severe motor paralysis was seen in 48 (34%). Higher AA levels (PR 1.243, 95% CI 1.042 to 1.483, p = 0.016) were independently associated with good overall recovery, and good recovery of upper and lower extremities separately (upper extremity: PR 1.319, 95% CI 1.101 to 1.580, p = 0.003; lower extremity: PR 1.293, 95% CI 1.115 to 1.499, p = 0.001).

CONCLUSIONS

Higher AA levels may contribute to a good early motor recovery in patients with severe motor paralysis due to ICH.

Production of conjugated linoleic acid by lactic acid bacteria; important factors and optimum conditions

Conjugated linoleic acid (CLA) has recently attracted significant attention as a health-promoting compound. CLA is a group of positional isomers of linoleic acid (LA) with a conjugated double bond naturally occurring in dairy and ruminant meat products. Microbial biosynthesis of CLA is a practical approach for commercial production due to its high safety and purity. There are some factors for the microbial CLA production such as strain type, microbial growth phase, pH, temperature and incubation time, based on which the amount and type of CLA can be controlled. Understanding the interplay of these factors is essential in optimizing the quantity and composition of microbial CLA, as discussed in the current study. Further exploration of CLA and its influences on human health remains a dynamic and evolving area of study.

Progress of Conjugated Linoleic Acid on Milk Fat Metabolism in Ruminants and Humans

As a valuable nutrient in milk, fat accounts for a significant proportion of the energy requirements of ruminants and is largely responsible for determining milk quality. Fatty acids (FAs) are a pivotal component of milk fat. Conjugated linoleic acid (CLA) is one of the naturally occurring FAs prevalent in ruminant dairy products and meat. Increasing attention has been given to CLA because of its anti-cancer, anti-inflammatory, immune regulation, and lipid metabolism regulation properties, and these benefits potentially contribute to the growth and health of infants. In breast milk, CLA is present in trace amounts, mainly in the form of cis-9, trans-11 CLA. Notably, cis-9, trans-11 CLA improves the milk fat rate while trans-10, cis-12 CLA inhibits it. Apart from having multiple physiological functions, CLA is also a pivotal factor in determining the milk quality of ruminants, especially milk fat rate. In response to growing interest in green and healthy functional foods, more and more researchers are exploring the potential of CLA to improve the production performance of animals and the nutritional value of livestock products. Taken together, it is novel and worthwhile to investigate how CLA regulates milk fat synthesis. It is the purpose of this review to clarify the necessity for studying CLA in ruminant milk fat and breast milk fat.