Development of a Reference Measurement Procedure and Certified Reference Material for the Determination of Hydroxyproline in Meat

Time-restricted feeding relieves high temperature-induced impairment on meat quality by activating the Nrf2/HO-1 pathway, modification of muscle fiber composition, and enriching the polyunsaturated fatty acids in pigs

To assess the effects of a time-restricted feeding (TRF) regimen on meat quality of pigs exposed to high ambient temperature, a two-month feeding and heat treatment (HT) trial was conducted using a 2 × 2 factorial design. A total of 24 growing pigs (11.0 ± 1.9 kg) were randomly divided into four groups: thermal neutral group (NT, 24 ± 3 °C), HT group (exposed to a high temperature at 35 ± 2 °C from 11:00 to 15:00), TRF group and HT + TRF group (HT and TRF co-treatment group, n = 6 for each group). Pigs in TRF groups got access to feed within 5 h from 9:00 to14:00, while the others were fed at 6:00, 11:30, and 16:00. All pigs received the same diet during the trail. The results showed that HT increased the drip loss, shear force, lightness, and malondialdehyde production in Longissimus thoracis et lumborum (LTL) muscle. TRF reversely reduced the shear force and drip loss, accompanied by decreased intramuscular fat and increased moisture content. Enhanced fiber transformation from type 1 to type 2b and down-regulated expression of muscle growth-related genes were observed by HT, while TRF suppressed the fiber transformation and expression of muscle atrophy-related genes. Furthermore, TRF restored the diminished protein expressions of Nrf2 and HO-1 in LTL muscle by chronic HT. Accumulation of HSP70 in muscle of HT group was reduced by treatment of TRF. HT declined the expression of vital genes involved in fatty acids poly-desaturation and the proportion of (polyunsaturated fatty acids) PUFAs, mainly omega-6 in LTL muscle, while TRF group promoted the expression of poly-desaturation pathway and displayed the highest proportion of PUFAs. These results demonstrated that TRF relieved the chronic high temperature affected meat quality by the restored expression of Nrf2/HO-1 anti-oxidative cascade, modified muscle fiber composition, and enriched PUFAs in LTL muscle.

Chiral secondary amino acids, their importance, and methods of analysis

Naturally occurring secondary amino acids, with proline as the main representative, contain an alpha-imino group in a cycle that is typically four-, five-, and six-membered. The unique ring structure exhibits exceptional properties-conformational rigidity, chemical stability, and specific roles in protein structure and folding. Many proline analogues have been used as valuable compounds for the study of metabolism of both prokaryotic and eukaryotic cells and for the synthesis of compounds with desired biological, pharmaceutical, or industrial properties. The D-forms of secondary amino acids play different roles in living organisms than the L-forms. They have different metabolic pathways, biological, physiological, and pharmacological effects, they can be indicators of changes and also serve as biomarkers of diseases. In the scientific literature, the number of articles examining D-amino acids in biological samples is increasing. The review summarises information on the occurrence and importance of D- and L-secondary amino acids-azetidic acid, proline, hydroxyprolines, pipecolic, nipecotic, hydroxypipecolic acids and related peptides containing these D-AAs, as well as the main analytical methods (mostly chromatographic) used for their enantiomeric determination in different matrices (biological samples, plants, food, water, and soil).

Inhaled nintedanib is well-tolerated and delivers key pharmacokinetic parameters required to treat bleomycin-induced pulmonary fibrosis

Oral nintedanib is marketed for the treatment of idiopathic pulmonary fibrosis (IPF), Systemic Sclerosis-Associated Interstitial Lung Disease and Chronic Fibrosing Interstitial Lung Diseases with a Progressive Phenotype. While effective at slowing fibrosis progression, as an oral medicine nintedanib has limitations. To reduce side effects and maximize efficacy, nintedanib was reformulated as a solution for nebulization and inhaled administration. To predict effectiveness treating IPF, inhalation was used as a tool to dissect the pharmacokinetic components required for nintedanib pulmonary anti-fibrotic activity. Following oral administration, nintedanib extensively partitioned into tissue and exhibited flip-flop pharmacokinetics, whereby resulting lung Cmax and AUC were substantially higher than plasma. By comparison, inhaled nintedanib was capable of delivering an oral-equivalent lung Cmax with lower local and systemic AUC. Using a multi-challenge bleomycin rat model, this distinct inhaled pharmacokinetic profile was dose responsive (0.05, 0.25 and 0.375 mg/kg), delivering oral-superior pulmonary anti-fibrotic activity with an equivalent delivered lung Cmax (QD inhaled 0.375 mg/kg versus BID oral 60 mg/kg). Possibly assisting this improvement, the infrequent high inhaled dose also improved bleomycin-challenged animal weight gain to levels equivalent to sham. By comparison, BID oral weight gain was substantially less than controls, suggesting a negative health impact on oral administered animals combating fibrosis. Both oral and inhaled administration exhibited anti-inflammatory activity, with oral achieving significance. In summary, inhalation (short-duration nintedanib lung Cmax without high local or systemic AUC) was well-tolerated and was effective reducing bleomycin-induced pulmonary fibrosis.