Reduction of fatty liver in rats by nicotinamide via the regeneration of the methionine cycle and the inhibition of aldehyde oxidase

Molecular mechanism and therapeutic significance of essential amino acids in metabolically associated fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), also known as metabolically associated fatty liver disease (MAFLD), is a systemic metabolic disease characterized by lipid accumulation in the liver, lipid toxicity, insulin resistance, intestinal dysbiosis, and inflammation that can progress from simple steatosis to nonalcoholic steatohepatitis (NASH) and even cirrhosis or cancer. It is the most prevalent illness threatening world health. Currently, there are almost no approved drug interventions for MAFLD, mainly dietary changes and exercise to control weight and regulate metabolic disorders. Meanwhile, the metabolic pathway involved in amino acid metabolism also influences the onset and development of MAFLD in the body, and most amino acid metabolism takes place in the liver. Essential amino acids are those amino acids that must be supplemented from outside the diet and that cannot be synthesized in the body or cannot be synthesized at a rate sufficient to meet the body's needs, including leucine, isoleucine, valine (collectively known as branched-chain amino acids), tryptophan, phenylalanine (which are aromatic amino acids), histidine, methionine, threonine and lysine. The metabolic balance of the body is closely linked to these essential amino acids, and essential amino acids are closely linked to the pathophysiological process of MAFLD. In this paper, we will focus on the metabolism of essential amino acids in the body and further explore the therapeutic strategies for MAFLD based on the studies conducted in recent years.

Nicotinamide supplementation alters plasma lipidomic profiles of peripartal dairy cows

Fatty liver syndrome, a common health problem in dairy cows, occurs during the transition from pregnancy to lactation. If the energy supplied to the cow's body cannot meet its needs, a negative energy balance ensues, and the direct response is fat mobilization. Nicotinamide (NAM) has been reported to reduce the nonesterified fatty acid concentration of postpartum plasma. To study the biochemical adaptations underlying this physiologic dysregulation, 12 dairy cows were sequentially assigned to a NAM (45 g/day) treatment or control group. Blood samples were collected on day (D) 1 and D21 relative to parturition. Changes to the plasma lipid metabolism of dairy cows in the two groups were compared using lipidomics. There were significant increases in plasma sphingomyelins d18:1/18:0, d18:1/23:0, d18:1/24:1, d18:1/24:0, and d18:0/24:0 in the NAM group on D1 relative to parturition. In addition, fatty acids 18:2, 18:1, 18:0, 16:1, and 16:0 were obviously decreased on D21 relative to calving. This research has provided insights into how NAM supplementation improves lipid metabolism in perinatal dairy cows.

Gas-phase ion migration spectrum analysis of the volatile flavors of large yellow croaker oil after different storage periods

The large yellow croaker, a species of fish found in the northwestern Pacific, is favored by consumers because of its prevalence in saltwater bodies, golden yellow abdomen, high calcium content, high protein, high fat content, and a flavor that originates from its lipids and volatile components. Volatile organic compounds significantly affect the aroma of food. In this work, electronic nose and headspace gas chromatography-ion mobility spectrometry were applied to analyze the flavor differences in fish oil durations. Through electronic nose system analysis, sensors W1C, W3S, W6S, and W2S directly affected fish oil flavor, and their flavor components were different. Gas chromatography-ion mobility spectrometry identified 26 volatile components (19 aldehydes, 3 ketones, 2 alcohols, 1 furan, and 1 olefin). (E,E)-2,4-hexadienal (D), (E,E)-2,4-hexadienal (M), 2,4-heptadienal (M), (E)-2-octenal, 2-propanone, 2-heptanone (M), 3-pentanone (D), and 1-octen-3-ol were the key flavor components of the fish oil. In conclusion, the combination of GC-IMS and PCA can identify the differences in flavor changes of large yellow croaker oil during 0–120 days storage. After 60 days storage, the types and signals of 2-propanone, 2-heptanone (M) components increase significantly. When 120 days storage, at this time, (E,E)-2,4-hexadienal (D), (E,E)-2,4-hexadienal (M), 2,4-heptadienal (M), (E)-2-octenal,(E)-2-octenal significantly. It has become the main flavor substance of fish oil. In summary, as the storage period increases, the components increase, and the oxidizing substances will increase, resulting in the deterioration of fish oil.

•

The oxidation state of Large yellow croaker oil in different storage periods was investigated.

•

The volatile compounds of Large yellow croaker oil were studied by GC-IMS.

•

The effects of storage period on the composition of large yellow croaker oil samples were tested.

•

We believe GC-IMS will play a crucial role in controlling the flavor of fish oil.

Nicotinamide supplementation in diabetic nonalcoholic fatty liver disease patients: randomized controlled trial

Background:

Nicotinamide has been reported to protect against liver steatosis and metabolic imbalances in nonalcoholic fatty liver disease (NAFLD) in animal models.

Objectives:

The objective was to investigate the efficacy and safety of nicotinamide supplementation in diabetic NAFLD patients.

Design:

This is a prospective randomized controlled open label study.

Methods:

Seventy diabetic NAFLD patients were randomly assigned either to the nicotinamide group (n = 35) who received nicotinamide 1000 mg once daily for 12 weeks in addition to their antidiabetic therapy or the control group (n = 35) who received their antidiabetic therapy only. The primary outcome was improvement in steatosis score, while secondary outcomes included assessment of liver stiffness, liver enzymes, lipid profile, insulin resistance, serum malondialdehyde, serum adiponectin, and patients’ quality of life (QOL).

Results:

Only 61 patients completed the study; 31 in the nicotinamide group and 30 in the control group. Comparisons between groups and within groups revealed nonsignificant changes in steatosis and fibrosis scores. However, significant reduction was observed in liver enzymes with a median decrease in alanine transaminase of 26.6% versus 0.74% in nicotinamide and control groups, respectively. After 12 weeks of treatment, the nicotinamide group showed significantly lower levels of low-density lipoprotein cholesterol (p value = 0.004), total cholesterol (p value = 0.006), and insulin resistance marker (p value = 0.005) compared with control. Serum triglycerides, malondialdehyde, and adiponectin levels were all comparable between the two groups. Regarding QOL, a significant improvement was detected in the total scores and the activity and fatigue domains scores.

Conclusion:

Nicotinamide at a dose of 1000 mg daily was tolerable, improved metabolic abnormalities and QOL of diabetic NAFLD patients with no effect on liver fibrosis or steatosis.

Trial Registration:

The study was registered at clinicaltrials.gov and given the ID number: ‘NCT03850886’. https://clinicaltrials.gov/ct2/show/NCT03850886.

Changes of Volatile Flavor Compounds in Large Yellow Croaker (Larimichthys crocea) during Storage, as Evaluated by Headspace Gas Chromatography-Ion Mobility Spectrometry and Principal Component Analysis

The large yellow croaker is one of the most economically important fish in Zhoushan, Zhejiang Province, and is well known for its high protein and fat contents, fresh and tender meat, and soft taste. However, the mechanisms involved in its flavor changes during storage have yet to be revealed, although lipid oxidation has been considered to be one important process in determining such changes. Thus, to explore the changes in the flavor of large yellow croaker fish meat during different storage periods, the main physical and chemical characteristics of the fish meat, including the acid value, peroxide value, p-anisidine value, conjugated diene value, and identities of the various flavor substances, were investigated and analyzed by multivariable methods, including headspace gas chromatography-ion mobility spectrometry (GC-IMS) and principal component analysis (PCA). It was found that after 60 d storage, the types and contents of the aldehyde and ketone aroma components increased significantly, while after 120 d, the contents of ketones (2-butanone), alcohols (1-propanethiol), and aldehydes (n-nonanal) decreased significantly. More specifically, aldehyde components dominated over ketones and lipids, while the n-nonanal content showed a downward trend during storage, and the 3-methylbutanol (trimer), 3-methylbutanol (dimer, D), 3-pentanone (D), and 3-pentanone (monomer) contents increased, whereas these compounds were identified as the key components affecting the fish meat flavor. Furthermore, after 120 d storage, the number of different flavor components reached its highest value, thereby confirming that the storage time influences the flavor of large yellow croaker fish. In this context, it should be noted that many of these compounds form through the Maillard reaction to accelerate the deterioration of fish meat. It was also found that after storage for 120 d, the physical indices of large yellow croaker meat showed significant changes, and its physicochemical properties varied. These results therefore demonstrate that a combination of GC-IMS and PCA can be used to identify the differences in flavor components present in fish meat during storage. Our study provides useful knowledge for understanding the different flavors associated with fish meat products during and following storage.