Differences In Free Fatty Acids Levels Research Articles

Non-Specific Elevated Serum Free Fatty Acids in Lung Cancer Patients: Nutritional or Pathological?

The reprogramming of lipid metabolism is a significant feature of tumors, yet the circulating levels of fatty acids in lung cancer patients remain to be explored. Moreover, the association between fatty acid levels and related factors, including nutritional intake, tumor metabolism, and tumor immunity, has been rarely discussed. To explore the differences in serum free fatty acids between lung cancer patients and healthy controls, and investigate the factors associated with this phenomenon. A case-control study enrolled 430 primary lung cancer patients and 430 healthy controls. The whole population had a medium [Q1, Q3] age of 48.0 [37.0, 58.9] years, with females comprising 56% of the participants. The absolute quantification of 27 serum free fatty acids (FFAs) was measured using a liquid chromatography-mass spectrometry (LC-MS/MS) detection. Data, including dietary intake, blood indicators, and gene expression of lung tissues, were obtained from questionnaires, blood tests, and RNA-sequencing. Statistical differences in FFA levels between lung cancer patients and healthy controls were investigated, and related contributing factors were explored. Levels of 22 FFAs were significantly higher in lung cancer patients compared to those in healthy controls, with fold changes ranging from 1.14 to 1.69. Lung cancer diagnosis models built with clinical and FFA features yielded an area under the receiver operating characteristic curve (AUROC) of 0.830 (0.780-0.880). Total fatty acids (TFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs) showed no significant dietary-serum associations, indicating that the elevations might not be attributed to an excessive intake of relevant fatty acids from the diet. For RNA-sequencing of lung tissues, among the 68 lipid metabolism genes, 26 genes showed significant upregulation (FDR < 0.05), while 33 genes exhibited significant downregulation, indicating the involvement of the fatty acids in the tumor metabolism. Through joint analysis with immune cells and inflammatory factors in the blood, fatty acids might exert suppressing effects on tumor immunity. Lung cancer patients had elevated levels of serum free fatty acids compared to healthy individuals. The elevations might not be attributed to an excessive intake of relevant fatty acids from the diet but related to pathological factors of tumor metabolism and immunity. These findings will complement research on fatty acid metabolism of lung cancer and provide insights into potential intervention targets.

Relationship of circulating levels of long-chain fatty acids to persistent organ failure in acute pancreatitis.

During acute pancreatitis (AP), free fatty acids (FFAs) are liberated from circulating triglycerides (TG) and injured adipocytes by pancreatic lipase. Circulating FFAs have been suspected as a source of systemic lipotoxicity in AP. However, assessment of FFAs is difficult and time-consuming, and little is known about relative levels of FFAs between patients with different severities of AP and controls. This study's aims were to assess early circulating levels of FFAs, (both saturated and unsaturated) in patients with AP vs. controls, and associations between FFA levels and AP severity. Serum samples from patients with AP were collected at enrollment (day 1 of hospital stay); serum samples were also collected from controls. FFAs including palmitic, palmitoleic, stearic, oleic, and linoleic acid were extracted and quantitated using gas chromatography separation. Severity of AP was determined by Revised Atlanta Classification. Differences in FFA levels and percentages of total FFAs were assessed between patients with AP and controls and patients with AP of different severity grades. A total of 93 patients with AP (48 female, 52%) and 29 controls (20 female, 69%) were enrolled. Of the patients with AP, 74 had mild/moderate and 19 had severe AP. Serum levels of all FFAs except stearic acid were significantly higher in patients with AP compared with controls. A strong and independent association between elevated palmitoleic acid levels and severe AP was found. Serum unsaturated FFA levels, specifically palmitoleic acid, appear to correlate with severe AP. These findings have potential clinical implications for targeted AP therapies.NEW & NOTEWORTHY Drivers of the inflammatory response in acute pancreatitis remain incompletely understood. Unsaturated fatty acids, specifically palmitoleic, appear to have an association with more severe acute pancreatitis. This finding presents a new clinical understanding of fatty acid toxicity and highlights a potential future target for treatment in severe acute pancreatitis.

Adipose tissue lipolysis and circulating lipids in acute and subacute critical illness: Effects of shock and treatment

PurposeThe purpose of this study is to assess lipid metabolism at the tissue level in critically ill subjects. Materials and methodsWe studied 182 patients with systemic inflammatory response syndrome/severe sepsis or shock during the acute (day 1) and subacute phase of critical illness (day 6). All subjects had a tissue microdialysis (MD) catheter placed in femoral adipose tissue upon admission to the intensive care unit (ICU). Plasma cholesterol, high-density lipoprotein, low-density lipoprotein, free fatty acids (FFAs), triglyceride, and MD glycerol (GLYC) were measured on days 1 and 6 in the ICU. ResultsOn admission, 56% of the patients had increased levels (>200 μmol/L) of MD GLYC. Patients with shock displayed more pronounced subcutaneous tissue lipolysis and more profound derangements of circulating lipids vs patients without shock (but no appreciable differences in FFA levels). Furthermore, in patients with shock during the acute period, there were positive, albeit weak, correlations of subcutaneous tissue lipolysis (MD GLYC), plasma FFAs (r = 0.260; P = .01), and norepinephrine's dose (r = 0.230; P = .01), whereas during the subacute phase, MD GLY levels were higher in patients receiving glucocorticoids (344.7 ± 276.0 μmol/L vs 252.2 ± 158.4 μmol/L; P = .03). ConclusionsSubcutaneous tissue lipolysis is only one of the many determinants of plasma FFAs. Routinely applied therapeutic modalities in the ICU interfere with adipose tissue metabolism.

Lactate and free fatty acids after subarachnoid hemorrhage

The hypothesis that lactate and free fatty acids (FFA) are elevated in the first minutes after subarachnoid hemorrhage (SAH) is tested. Adult rats were subjected to an endovascular SAH through the right internal carotid artery while under anesthesia. The brains were frozen in-situ at 15, 30, 60 min, and 24 h post-hemorrhage. Regional measures of tissue lactic acid and FFA were made in the hippocampi, ipsilateral cortex, contralateral cortex, and cerebellum. Lactic acid levels were significantly elevated from sham animals in each region within the first hour ( p<0.0001 cerebellum, right, and contralateral cortex, p<0.01 hippocampus), but did not change significantly over the first hour. At 24 h post-hemorrhage, there was no significant difference in the lactic acid levels from controls. Similarly, total FFA were significantly higher in each region as compared to sham operated controls within the first hour ( p<0.001 cerebellum, p<0.05 hippocampus, p<0.05 contralateral cortex, p<0.0001 ipsilateral cortex). By 24 h, there was no significant difference in FFA levels from shams. The data indicate that aerobic metabolism fails and cellular damage with degradation of cell membranes occurs in the first minutes after SAH, and lasts for at least 1 h. However, this process is stabilized within 24 h in our model. Although the largest effect was seen in the ipsilateral cortex, all areas of the brain were effected.

Effect of intravenous caffeine on muscle glycogenolysis in fasted exercising rats

Caffeine has been reported to enhance performance by increasing fat utilization and by sparing liver and muscle glycogen. The lipolytic effect of caffeine has been reported to be diminished in response to previous carbohydrate loading of the subjects. The present study was designed to investigate the effects of caffeine during submaximal exercise in rats where the influence of dietary carbohydrate was removed by fasting. Rats were fasted overnight and given injection of 25 mg.kg-1 caffeine (CAF) or 0.9% NaCl (SAL) 60 min before exercise. They were run for 15, 30, and 60 min on a rodent treadmill up a 15% grade at 21 m.min-1. Plasma free fatty acids (FFA) were significantly elevated to 0.72 +/- 0.04 mM in CAF as compared to 0.45 +/- 0.03 mM in SAL at the beginning of exercise. During exercise, however, a significant difference in FFA levels between CAF and SAL was seen only at 30 min and not at other time points. No significant decrease in muscle glycogenolysis was observed in the CAF as compared to SAL rats, and the liver cyclic AMP remained the same in both CAF and SAL. Blood lactate (mM) showed an increase due to caffeine only at 15 min of exercise (CAF = 2.4 +/- 0.2; SAL = 1.7 +/- 0.3). Intravenous caffeine during exercise did not alter plasma glucagon or blood glucose. We conclude that caffeine has no effect on muscle glycogen utilization in fasted rats during exercise even though there was an increased FFA in CAF rats at the beginning of exercise.

Seasonal changes in serum free fatty acid level in the migratory Canada goose.

The changes in the serum level of free fatty acids (FFA) in the migratory Canada goose (Branta canadensis interior) breeding in Ft. Churchill (Manitoba, Canada) and wintering in Swan Lake (Missouri, U.S.A.), were studied during the different periods of its yearly life cycle. The lowest serum FFA level was noted during the spring premigratory phase (early March) at Swan Lake, and the highest during moult (early August) at Ft. Churchill. Serum FFA level during the spring postmigratory period (early May at Ft. Churchill) was significantly higher than that during the spring premigratory period and the breeding period (early at Ft. Churchill). No signigicant difference in FFA levels was noted between the fall premigratory (early September at Ft. Churchill) and the fall postmigratory (mid-October at Swan Lake) periods. The significance of the seasonal variations in serum FFA level is discussed in relation to the cyclic physiological events taking place in the bird.