Potential Role of Lauric Acid in Milk Fat Synthesis in Chinese Holstein Cows Based on Integrated Analysis of Ruminal Microbiome and Metabolome.

The composition and metabolic profile of the ruminal microbiome have an impact on milk composition. To unravel the ruminal microbiome and metabolome affecting milk fat synthesis in dairy cows, 16S rRNA and internal transcribed spacer (ITS) gene sequencing, as well as ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) methods were used to investigate the significant differences in ruminal bacterial and fungal communities as well as metabolome among Chinese Holstein cows with contrasting milk fat contents under the same diet (H-MF 5.82 ± 0.41% vs. L-MF 3.60 ± 0.12%). Another objective was to culture bovine mammary epithelial cells (BMECs) to assess the effect of metabolites on lipid metabolism. Results showed that the acetate-to-propionate ratio and xylanase activity in ruminal fluid were both higher in H-MF. Microbiome sequencing identified 10 types of bacteria and four types of fungi differently abundant at the genus level. Metabolomics analysis indicated 11 different ruminal metabolites between the two groups, the majority of which were lipids and organic acids. Among these, lauric acid (LA) was enriched in fatty acid biosynthesis with its concentration in milk fat of H-MF cows being greater (217 vs. 156 mg per 100 g milk), thus, it was selected for an in vitro study with BMECs. Exogenous LA led to a marked increase in intracellular triglyceride (TG) content and lipid droplet formation, and it upregulated the mRNA abundance of fatty acid uptake and activation (CD36 and ACSL1), TG synthesis (DGAT1, DGAT2 and GPAM), and transcriptional regulation (SREBP1) genes. Taken together, the greater relative abundance of xylan-fermenting bacteria and fungi, and lower abundance of bacteria suppressing short-chain fatty acid-producing bacteria or participating in fatty acid hydrogenation altered lipids and organic acids in the rumen of dairy cows. In BMECs, LA altered the expression of genes involved in lipid metabolism in mammary cells, ultimately promoting milk fat synthesis. Thus, it appears that this fatty acid plays a key role in milk fat synthesis.

Abundance of solute carrier family 27 member 6 (SLC27A6) in the bovine mammary gland alters fatty acid metabolism.

Milk fatty acid (FA) composition is associated with the nutritional value of milk and is known to vary with the stage of lactation. Although biochemical aspects controlling FA metabolism in the bovine mammary gland are well-established, less is known about the underlying molecular mechanisms. Thus, to address some of these shortcomings, the present study sought to evaluate milk FA composition and mammary transcriptome profiles at different stages of lactation. Compared with 90 d of lactation, at 315 d of lactation, there was an increase in the concentrations of C18:2, polyunsaturated fatty acids (PUFA), and short-chain fatty acids (SCFA), and a decrease in C16:0 and long-chain fatty acids (LCFA) in milk. To further identify candidate genes and pathways responsible for these phenotypic differences, the transcriptome of bovine mammary tissue at 90 d (peak) and 315 d (late) of lactation was profiled using RNA-seq. A total of 827 differentially expressed genes were identified. Bioinformatic analysis revealed that the major differentially modulated lipid metabolic pathways were the PPAR signaling pathway, alpha-linolenic acid metabolism and linoleic acid metabolism. Compared with peak lactation, the mammary tissue at late lactation had lower abundance of genes related to FA transport and activation (CD36, SLC27A6, ACSM1, FABP3 and FABP4). Thus, to further explore the role of FA transport into mammary cells, we knocked down fatty acid transport protein 6 (solute carrier family 27 member 6, SLC27A6) in the bovine mammary epithelial cells (BMECs) using siRNA. The knockdown of SLC27A6 dramatically downregulated the mRNA abundance of genes associated with FA activation (ACSL4), oxidation (CPT1A) and transport (CD36), while the abundance of genes associated with transcription regulation (PPARG), diacylglycerol acyltransferase 1 (DGAT1), FA binding (FABP3), and desaturation (FADS2) was upregulated. In addition, SLC27A6 silenced the intracellular content of triglyceride (TG) and the percentage of C18:1cis9 and C20:4cis5,8,11,14 was greater, whereas that of C16:0 and C18:0 was lower. Overall, in vivo results indicated that LCFA transport into mammary cells during late lactation partly explains the difference in the FA profiles. In vitro analyses underscored how FA transport via SLC27A6 could dictate in part the intracellular utilization of FA for TG synthesis versus oxidation. The data provide strong support for a central role of SLC27A6 in the regulation of FA metabolism in BMECs.

Interlocking intramedullary nail fixation with additional bone grafting from trochanter via a femoral hollow trephine in the treatment of femoral shaft fractures: design and clinical application.

PURPOSE: The purpose of this study was to describe and evaluate the clinical application of the technique of interlocking intramedullary (IM) nailing via an entry point at the tip of greater trochanter using a specially designed femoral hollow trephine to stabilize diaphyseal fractures of the femur. METHODS: From February 2010 to April 2014, 35 consecutive patients with femoral shaft fractures were treated by the therapy of bone grafting from trochanter region with interlocking IM nail. The average age of these 23 male and 12 female patients was 37.5 years (range, 22-67 years). Fractures were classified according to AO classification system (15 type A, 17 type B, 3 type C). Femoral canal reaming and the collection of cancellous bone were simultaneously performed in a single step with the specially designed femoral hollow trephine, followed by regular IM nailing procedure. RESULTS: Of the 35 cases, the mean volume of spongy bone obtained was 5.63 cm3 (range, 3.0-7.0 cm3). Thirty-five patients with femoral shaft fractures had a mean follow-up period of 16.2 months (range, 12-22 months). All patients achieved bony union, at a mean of 5.4 months (range, 4-6 months). No patient developed a delayed union or a nonunion. There were no complications such as infections, injury of vascular and nerve, or heterotopic ossification in hip. CONCLUSIONS: These results indicate that the technique of use of IM nailing with the femoral hollow trephine significantly decreases the occurrence of nonunion in femoral shaft fractures.

[Bridging fixation with locking plate for the treatment of subtrochanteric femoral fractures of Seinsheimer type V].

OBJECTIVE: To investigate the clinical effect of bridging fixation with locking plate for the Seinsheimer type V subtrochanteric femoral fracture. METHODS: From March 2009 to September 2014,18 cases of Seinsheimer type V subtrochanteric femoral fracture were treated by open reduction and bridging fixation with locking plate through proximal and distal approach including 16 males and 2 females with an average age of 41 years old ranging from 22 to 67 years old. Among them, 12 cases caused by traffic accident, 5 cases by falling, 1 case by heavy aboving. All cases were fresh and closed fractures. Time between injury and operation was from 4 to 9 days with an average of 6.2 days. Of them, 11 cases were fixed with reverse LISS and the other 7 cases were fixed with anatomical locking plates of proximal femur. RESULTS: The mean time of operation was 110 min (ranged from 90 to 155 min). The mean blood loss during operation was 425 ml (ranged from 350 to 650 ml) and 16 cases got blood transfusion which was meanly 300 ml. The mean hospital time was 14 days (ranged from 12 to 18 days). The mean duration of followed up was 11.8 months (ranged from 8 to 22 months). The mean time of bone union was 6.6 months (ranged from 5 to 8 months). There was not any complication such as infection, implant failure, hip varus, external rotation deformity of low limb or fat embolism. The Sanders hip scores were 53.22 ± 6.48, the result was excellent in 12 cases and good in 6 cases at the last follow-up. CONCLUSION: Under the principle of biological osteosynthesis, treatment of Seinsheimer type V subtrochanteric femoral fracture with bridging locking plate fixation has such advantages as high mechanism, less interference of blood supply, stable fixation and little complication. It is a safe and idea way for the treatment of the Seinsheimer type V subtrochanteric femoral fracture.

[Case-control study on close reduction combined with minimally invasive percutaneous plate osteosynthesis for the treatment of distal fracture of tibial shaft].

OBJECTIVE: To compare the effects of close reduction combined with minimally invasive percutaneous plate osteosynthesis for distal fracture of tibial shaft. METHODS: From March 2009 to May 2013, there were 124 patients (89 males and 35 females, 30 of them were injured in a traffic accident and 94 were falling down in daily life, the ages ranging from 21 to 81 years old) who suffered from distal fracture of tibial shaft. Sixty-six patients (48 males and 18 females, 45 cases of type A, 12 cases of type B and 9 cases of type C) were treated with close manipulative reduction combined with minimally invasive percutaneous plate fixation. After close reduction, a minimal incision was made and a anatomic plate was inserted just along the medial tibia periostea, and then the fracture was fixed without fracture exposure. The other 58 patients (41 males and 17 females, 41 cases of type A, 10 cases of type B and 7 cases of type C) were treated with conventional open reduction and internal fixation. Length of the incision, operating time, early postoperative pain (recorded using the Visual Analog Scale score) and the outcome results (recorded using the evaluation standard of Johner-Wruhs) were compared. RESULTS: The length of incision was meanly (7.34 ± 1.42) cm in MIPPO group and (21.82 ± 2.35) cm in ORIF group; operation time was (44.48 ± 10.00) min in MIPPO group and (59.42 ± 11.84) min in ORIF group. The postoperative radiographs verified good position of all screws and satisfactory bone fracture reduction in both groups. All the patients were followed up, and the duration ranged from 10 to 24 months (mean 15.2 months) in both groups. In MIPPO group,only one patient had delayed union and got union after Chinese herb therapy. The other 65 patients got bony union during 15 to 20 weeks. While in ORIF group, 3 patients suffered from nonunion and received reoperation with bone grafting, and 4 patients got bone infection. CONCLUSION: Treatment of distal fracture of tibial shaft, combined with close reduction and MIPPO technique, has the advantages such as less invasion, less damage of blood supply, simplified procedure of operation and higher union rate, which is an ideal methods and is accordant to the biological demand.