Accumulation of Long-Chain Glycosphingolipids during Aging Is Prevented by Caloric Restriction

Chronic kidney disease and end-stage renal disease are major causes of morbidity and mortality that are seen far more commonly in the aged population. Interestingly, kidney function declines during aging even in the absence of underlying renal disease. Declining renal function has been associated with age-related cellular damage and dysfunction with reports of increased levels of apoptosis, necrosis, and inflammation in the aged kidney. Bioactive sphingolipids have been shown to regulate these same cellular processes, and have also been suggested to play a role in aging and cellular senescence.We hypothesized that alterations in kidney sphingolipids play a role in the declining kidney function that occurs during aging. To begin to address this, the sphingolipid profile was measured in young (3 mo), middle aged (9 mo) and old (17 mo) C57BL/6 male mice. Interestingly, while modest changes in ceramides and sphingoid bases were evident in kidneys from older mice, the most dramatic elevations were seen in long-chain hexosylceramides (HexCer) and lactosylceramides (LacCer), with C14- and C16-lactosylceramides elevated as much as 8 and 12-fold, respectively. Increases in long-chain LacCers during aging are not exclusive to the kidney, as they also occur in the liver and brain. Importantly, caloric restriction, previously shown to prevent the declining kidney function seen in aging, inhibits accumulation of long-chain HexCer/LacCers and prevents the age-associated elevation of enzymes involved in their synthesis. Additionally, long-chain LacCers are also significantly elevated in human fibroblasts isolated from elderly individuals.This study demonstrates accumulation of the glycosphingolipids HexCer and LacCer in several different organs in rodents and humans during aging. In addition, data demonstrate that HexCer and LacCer metabolism is regulated by caloric restriction. Taken together, data suggest that HexCer/LacCers are important mediators of cellular processes fundamental to mammalian aging

Mucosal Targeting of a BoNT/A Subunit Vaccine Adjuvanted with a Mast Cell Activator Enhances Induction of BoNT/A Neutralizing Antibodies in Rabbits

We previously reported that the immunogenicity of Hcβtre, a botulinum neurotoxin A (BoNT/A) immunogen, was enhanced by fusion to an epithelial cell binding domain, Ad2F, when nasally delivered to mice with cholera toxin (CT). This study was performed to determine if Ad2F would enhance the nasal immunogenicity of Hcβtre in rabbits, an animal model with a nasal cavity anatomy similar to humans. Since CT is not safe for human use, we also tested the adjuvant activity of compound 48/80 (C48/80), a mast cell activating compound previously determined to safely exhibit nasal adjuvant activity in mice.New Zealand White or Dutch Belted rabbits were nasally immunized with Hcβtre or Hcβtre-Ad2F alone or combined with CT or C48/80, and serum samples were tested for the presence of Hcβtre-specific binding (ELISA) or BoNT/A neutralizing antibodies.Hcβtre-Ad2F nasally administered with CT induced serum anti-Hcβtre IgG ELISA and BoNT/A neutralizing antibody titers greater than those induced by Hcβtre + CT. C48/80 provided significant nasal adjuvant activity and induced BoNT/A-neutralizing antibodies similar to those induced by CT.Ad2F enhanced the nasal immunogenicity of Hcβtre, and the mast cell activator C48/80 was an effective adjuvant for nasal immunization in rabbits, an animal model with a nasal cavity anatomy similar to that in humans

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Sphingolipids in High Fat Diet and Obesity-Related Diseases

Nutrient oversupply associated with a high fat diet (HFD) significantly alters cellular metabolism, and specifically including sphingolipid metabolism. Sphingolipids are emerging as bioactive lipids that play key roles in regulating functions, in addition to their traditional roles as membrane structure. HFD enhances de novo sphingolipid synthesis and turnover of sphingolipids via the salvage pathway, resulting in the generation of ceramide, and more specifically long chain ceramide species. Additionally, HFD elevates sphingomyelin and sphingosine-1 phosphate (S1P) levels in several tissues including liver, skeletal muscle, adipose tissue, and cardiovascular tissues. HFD-stimulated sphingolipid generation contributes to systemic insulin resistance, dysregulated lipid accumulation, and cytokine expression and secretion from skeletal muscle and adipose tissues, exacerbating obesity-related conditions. Furthermore, altered sphingolipid levels, particularly ceramide and sphingomyelin, are involved in obesity-induced endothelial dysfunction and atherosclerosis. In this review, HFD-mediated sphingolipid metabolism and its impact on HFD-induced biology and pathobiology will be discussed

Therapeutic Potential for Sphingolipids in Inflammatory Bowel Disease and Colorectal Cancer

Inflammatory bowel disease (IBD), characterized by chronic inflammation in the intestinal tract, increases the risk for the development of colorectal cancer (CRC). Sphingolipids, which have been implicated in IBD and CRC, are a class of bioactive lipids that regulate cell signaling, differentiation, apoptosis, inflammation, and survival. The balance between ceramide (Cer), the central sphingolipid involved in apoptosis and differentiation, and sphingosine-1-phosphate (S1P), a potent signaling molecule involved in proliferation and inflammation, is vital for the maintenance of normal cellular function. Altered sphingolipid metabolism has been implicated in IBD and CRC, with many studies highlighting the importance of S1P in inflammatory signaling and pro-survival pathways. A myriad of sphingolipid analogues, inhibitors, and modulators have been developed to target the sphingolipid metabolic pathway. In this review, the efficacy and therapeutic potential for modulation of sphingolipid metabolism in IBD and CRC will be discussed

Inhibition of sphingosine kinase-2 in a murine model of lupus nephritis.

Sphingosine-1-phosphate (S1P), a potent bioactive lipid, is emerging as a central mediator in inflammation and immune responses. We have previously implicated S1P and its synthetic enzyme sphingosine kinase (SK) in inflammatory and autoimmune disorders, including inflammatory bowel disease and rheumatoid arthritis. Generation of S1P requires phosphorylation of sphingosine by SK, of which there are two isoforms. Numerous studies have implicated SK1 in immune cell trafficking, inflammation and autoimmune disorders. In this study, we set out to determine the role of SK and S1P in lupus nephritis (LN). To this end, we examined S1P and dihydro-S1P (dh-S1P) levels in serum and kidney tissues from a mouse model of LN. Interestingly dh-S1P was significantly elevated in serum and kidney tissue from LN mice, which is more readily phosphorylated by SK2. Therefore, we employed the use of the specific SK2 inhibitor, ABC294640 in our murine model of LN. Treatment with ABC294640 did not improve vascular or interstitial pathology associated with LN. However, mice treated with the SK2 inhibitor did demonstrate decreases in glomerular pathology and accumulation of B and T cells in the spleen these were not statistically different from lpr mice treated with vehicle. LN mice treated with ABC294640 did not have improved urine thromboxane levels or urine proteinuria measurements. Both S1P and dh-S1P levels in circulation were significantly reduced with ABC294640 treatment; however, dh-S1P was actually elevated in kidneys from LN mice treated with ABC294640. Together these data demonstrate a role for SKs in LN; however, they suggest that inhibition of SK1 or perhaps both SK isoforms would better prevent elevations in S1P and dh-S1P and potentially better protect against LN

Increase in kidney Dh-S1P is not prevented by ABC294640 in lupus mice.

<p>After 10 weeks of ABC294640 or vehicle administration, kidneys were collected from MRL/MpJ or MLR/lpr mice. Kidney tissue was homogenized and analyzed for sphingolipid content by the Lipidomics Shared Resource at MUSC, <b>A</b>) sphingosine, <b>B</b>) S1P, <b>C</b>) Dh-sphingosine and <b>D</b>) Dh-S1P. Data represent mean ± SEM, n≥10; *p<0.05, **p<0.01, ***p<0.001 treated vs. MPJ.</p