The levels and composition of sphingolipids and related metabolites are altered in aging and common disorders such as diabetes and cancers, as well as in neurodegenerative, cardiovascular, and respiratory diseases. Changes in sphingolipids have been implicated as being an essential step in mitochondria-driven cell death. However, little is known about the precise sphingolipid composition and modulation in mitochondria or related organelles. Here, we used LC–MS/MS to analyze the presence of key components of the ceramide metabolic pathway in vivo and in vitro in purified endoplasmic reticulum (ER), mitochondria-associated membranes (MAM), and mitochondria. Specifically, we analyzed the sphingolipids in the three pathways that generate ceramide: sphinganine in the de novo ceramide pathway, sphingomyelin in the breakdown pathway, and sphingosine in the salvage pathway. We observed sphingolipid profiles in mouse liver, mouse brain, and a human glioma cell line (U251). We analyzed the quantitative and qualitative changes of these sphingolipids during staurosporine (STS)-induced apoptosis in U251 cells. Ceramide, especially C16-ceramide, levels increased during early apoptosis possibly through a conversion from mitochondrial sphinganine and sphingomyelin, but sphingosine and lactosyl- and glucosyl-ceramide levels were unaffected. We also found that ceramide generation is enhanced in mitochondria when sphingomyelin levels are decreased in the MAM. This decrease was associated with an increase in acid sphingomyelinase (ASM) activity in MAM. We conclude that meaningful sphingolipid modifications occur in MAM, the mitochondria, and ER during the early phases of apoptosis.

Withdrawn by Author.

APOA5 is a low-abundance exchangeable apolipoprotein that plays critical roles in human triglyceride (TG) metabolism. Indeed, aberrations in the plasma concentration or structure of APOA5 are linked to hypertriglyceridemia, hyperchylomicronemia, myocardial infarction risk, obesity, and coronary artery disease. While it has been successfully produced at low yield in bacteria, the resulting protein had limitations for structure-function studies due to its low solubility under physiological buffer conditions. We hypothesized that the yield and solubility of recombinant APOA5 could be increased by: i) engineering a fusion protein construct in a codon optimized expression vector, ii) optimizing an efficient refolding protocol, and iii) screening buffer systems at physiological pH. The result was a high-yield (25 mg/l) bacterial expression system that produces lipid-free APOA5 soluble at concentrations of up to 10 mg/ml at a pH of 7.8 in bicarbonate buffers. Physical characterization of lipid-free APOA5 indicated that it exists as an array of multimers in solution, and far UV circular dichroism analyses show differences in total α-helicity between acidic and neutral pH buffering conditions. The protein was functional in that it bound and emulsified multilamellar dimyristoyl-phosphatidylcholine vesicles and could inhibit postprandial plasma TG accumulation when injected into C57BL/6J mice orally gavaged with Intralipid.

We previously described the expression of CD36 and LPL by breast cancer (BC) cells and tissues and the growth-promoting effect of VLDL observed only in the presence of LPL. We now report a model in which LPL is bound to a heparan sulfate proteoglycan motif on the BC cell surface and acts in concert with the VLDL receptor to internalize VLDLs via receptor-mediated endocytosis. We also demonstrate that gene-expression programs for lipid synthesis versus uptake respond robustly to triglyceride-rich lipoprotein availability. The literature emphasizes de novo FA synthesis and exogenous free FA uptake using CD36 as paramount mechanisms for lipid acquisition by cancer cells. We find that the uptake of intact lipoproteins is also an important mechanism for lipid acquisition and that the relative reliance on lipid synthesis versus uptake varies among BC cell lines and in response to VLDL availability. This metabolic plasticity has important implications for the development of therapies aimed at the lipid dependence of many types of cancer, in that the inhibition of FA synthesis may elicit compensatory upregulation of lipid uptake. Moreover, the mechanism that we have elucidated provides a direct connection between dietary fat and tumor biology.­.

Elevated levels of triglyceride-rich lipoproteins (TRLs), both fasting and postprandial, are associated with increased risk for atherosclerosis. However, guidelines for treatment are defined solely by fasting lipid levels, even though postprandial lipids may be more informative. In the postprandial state, circulating lipids consist of dietary fat transported from the intestine in chylomicrons (CMs; containing ApoB48) and fat transported from the liver in VLDL (containing ApoB100). Research into the roles of endogenous versus dietary fat has been hindered because of the difficulty in separating these particles by ultracentrifugation. CM fractions have considerable contamination from VLDL (purity, 10%). To separate CMs from VLDL, we produced polyclonal antibodies against ApoB100 and generated immunoaffinity columns. TRLs isolated by ultracentrifugation of plasma were applied to these columns, and highly purified CMs were collected (purity, 90–94%). Overall eight healthy unmedicated adult volunteers (BMI, 27.2 ± 1.4 kg/m²; fasting triacylglycerol, 102.6 ± 19.5 mg/dl) participated in a feeding study, which contained an oral stable-isotope tracer (1-¹³C acetate). We then used this technique on plasma samples freshly collected during an 8 h human feeding study from a subset of four subjects. We analyzed fractionated lipoproteins by Western blot, isolated and derivatized triacylglycerols, and calculated fractional de novo lipogenesis. The results demonstrated effective separation of postprandial lipoproteins and substantially improved purity compared with ultracentrifugation protocols, using the immunoaffinity method. This method can be used to better delineate the role of dietary sugar and fat on postprandial lipids in cardiovascular risk and explore the potential role of CM remnants in atherosclerosis.

Whether HDL is associated with dementia risk is unclear. In addition to apoA1, other apolipoproteins are found in HDL, creating subspecies of HDL that may have distinct metabolic properties. We measured apoA1, apoC3, and apoJ levels in plasma and apoA1 levels in HDL that contains or lacks apoE, apoJ, or apoC3 using a modified sandwich ELISA in a case-cohort study nested within the Ginkgo Evaluation of Memory Study. We included 995 randomly selected participants and 521 participants who developed dementia during a mean of 5.1 years of follow-up. The level of total apoA1 was not significantly related to dementia risk, regardless of the coexistence of apoC3, apoJ, or apoE. Higher levels of total plasma apoC3 were associated with better cognitive function at baseline (difference in Modified Mini-Mental State Examination scores tertile 3 vs. tertile 1: 0.60; 95% CI: 0.23, 0.98) and a lower dementia risk (adjusted hazard ratio tertile 3 vs. tertile 1: 0.73; 95% CI: 0.55, 0.96). Plasma concentrations of apoA1 in HDL and its apolipoprotein-defined subspecies were not associated with cognitive function at baseline or with the risk of dementia during follow-up. Similar studies in other populations are required to better understand the association between apoC3 and Alzheimer’s disease pathology.

apoB exists as apoB100 and apoB48, which are mainly found in hepatic VLDLs and intestinal chylomicrons, respectively. Elevated plasma levels of apoB-containing lipoproteins (Blps) contribute to coronary artery disease, diabetes, and other cardiometabolic conditions. Studying the mechanisms that drive the assembly, intracellular trafficking, secretion, and function of Blps remains challenging. Our understanding of the intracellular and intraorganism trafficking of Blps can be greatly enhanced, however, with the availability of fusion proteins that can help visualize Blp transport within cells and between tissues. We designed three plasmids expressing human apoB fluorescent fusion proteins: apoB48-GFP, apoB100-GFP, and apoB48-mCherry. In Cos-7 cells, transiently expressed fluorescent apoB proteins colocalized with calnexin and were only secreted if cells were cotransfected with microsomal triglyceride transfer protein. The secreted apoB-fusion proteins retained the fluorescent protein and were secreted as lipoproteins with flotation densities similar to plasma HDL and LDL. In a rat hepatoma McA-RH7777 cell line, the human apoB100 fusion protein was secreted as VLDL- and LDL-sized particles, and the apoB48 fusion proteins were secreted as LDL- and HDL-sized particles. To monitor lipoprotein trafficking in vivo, the apoB48-mCherry construct was transiently expressed in zebrafish larvae and was detected throughout the liver. These experiments show that the addition of fluorescent proteins to the C terminus of apoB does not disrupt their assembly, localization, secretion, or endocytosis. The availability of fluorescently labeled apoB proteins will facilitate the exploration of the assembly, degradation, and transport of Blps and help to identify novel compounds that interfere with these processes via high-throughput screening.

The composition-function relationship of HDL particles and its effects on the mechanisms driving coronary heart disease (CHD) is poorly understood. We tested the hypothesis that the functionality of HDL particles is significantly influenced by their lipid composition. Using a novel 3D-separation method, we isolated five different-sized HDL subpopulations from CHD patients who had low preβ-1 functionality (low-F) (ABCA1-dependent cholesterol-efflux normalized for preβ-1 concentration) and controls who had either low-F or high preβ-1 functionality (high-F). Molecular numbers of apoA-I, apoA-II, and eight major lipid classes were determined in each subpopulation by LC-MS. The average number of lipid molecules decreased from 422 in the large spherical α-1 particles to 57 in the small discoid preβ-1 particles. With decreasing particle size, the relative concentration of free cholesterol (FC) decreased in α-mobility but not in preβ-1 particles. Preβ-1 particles contained more lipids than predicted; 30% of which were neutral lipids (cholesteryl ester and triglyceride), indicating that these particles were mainly remodeled from larger particles not newly synthesized. There were significant correlations between HDL-particle functionality and the concentrations of several lipids. Unexpectedly, the phospholipid:FC ratio was significantly correlated with large-HDL-particle functionality but not with preβ-1 functionality. There was significant positive correlation between particle functionality and total lipids in high-F controls, indicating that the lipid-binding capacity of apoA-I plays a major role in the cholesterol efflux capacity of HDL particles. Functionality and lipid composition of HDL particles are significantly correlated and probably both are influenced by the lipid-binding capacity of apoA-I.

The hydrolysis of triglycerides in triglyceride-rich lipoproteins by LPL is critical for the delivery of triglyceride-derived fatty acids to tissues, including heart, skeletal muscle, and adipose tissues. Physiologically active LPL is normally bound to the endothelial cell protein glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1), which transports LPL across endothelial cells, anchors LPL to the vascular wall, and stabilizes LPL activity. Disruption of LPL-GPIHBP1 binding significantly alters triglyceride metabolism and lipid partitioning. In this study, we modified the NanoLuc® Binary Technology split-luciferase system to develop a novel assay that monitors the binding of LPL to GPIHBP1 on endothelial cells in real time. We validated the specificity and sensitivity of the assay using endothelial lipase and a mutant version of LPL and found that this assay reliably and specifically detected the interaction between LPL and GPIHBP1. We then interrogated various endogenous and exogenous inhibitors of LPL-mediated lipolysis for their ability to disrupt the binding of LPL to GPIHBP1. We found that angiopoietin-like (ANGPTL)4 and ANGPTL3-ANGPTL8 complexes disrupted the interactions of LPL and GPIHBP1, whereas the exogenous LPL blockers we tested (tyloxapol, poloxamer-407, and tetrahydrolipstatin) did not. We also found that chylomicrons could dissociate LPL from GPIHBP1 and found evidence that this dissociation was mediated in part by the fatty acids produced by lipolysis. These results demonstrate the ability of this assay to monitor LPL-GPIHBP1 binding and to probe how various agents influence this important complex.

Loss of pancreatic β-cell mass and function as a result of sustained ER stress is a core step in the pathogenesis of diabetes mellitus type 2. The complex control of β-cells and insulin production involves hedgehog (Hh) signaling pathways as well as cholesterol-mediated effects. In fact, data from studies in humans and animal models suggest that HDL protects against the development of diabetes through inhibition of ER stress and β-cell apoptosis. We investigated the mechanism by which HDL inhibits ER stress and apoptosis induced by thapsigargin, a sarco/ER Ca²⁺-ATPase inhibitor, in β-cells of a rat insulinoma cell line, INS1e. We further explored effects on the Hh signaling receptor Smoothened (SMO) with pharmacologic agonists and inhibitors. Interference with sterol synthesis or efflux enhanced β-cell apoptosis and abrogated the anti-apoptotic activity of HDL. During ER stress, HDL facilitated the efflux of specific oxysterols, including 24-hydroxycholesterol (OHC). Supplementation of reconstituted HDL with 24-OHC enhanced and, in cells lacking ABCG1 or the 24-OHC synthesizing enzyme CYP46A1, restored the protective activity of HDL. Inhibition of SMO countered the beneficial effects of HDL and also LDL, and SMO agonists decreased β-cell apoptosis in the absence of ABCG1 or CYP46A1. The translocation of the SMO-activated transcription factor glioma-associated oncogene GLI-1 was inhibited by ER stress but restored by both HDL and 24-OHC. In conclusion, the protective effect of HDL to counter ER stress and β-cell death involves the transport, generation, and mobilization of oxysterols for activation of the Hh signaling receptor SMO

Monogenic forms of obesity have been identified in ≤10% of severely obese European patients. However, the overall spectrum of deleterious variants (point mutations and structural variants) responsible for childhood severe obesity remains elusive. In this study, we genetically screened 225 severely obese children from consanguineous Pakistani families through a combination of techniques including an in-house developed augmented whole-exome sequencing (CoDE-seq) enabling simultaneous detection of whole exome copy number variations (CNVs) and of point mutations in coding regions. We identified 110 probands (49%) carrying 55 different pathogenic point mutations and CNVs in 13 genes/loci responsible for non-syndromic and syndromic monofactorial obesity. CoDE-seq also identified 28 rare or novel CNVs associated with intellectual disability in 22 additional obese subjects (10%). Additionally, we highlight variants in candidate genes for obesity warranting further investigation. Altogether, 59% of the studied cohort are likely to have a discrete genetic cause with 13% of these due to CNVs demonstrating a remarkably higher prevalence of monofactorial obesity than hitherto reported and a plausible over lapping of obesity and intellectual disabilities in several cases. Finally, inbred populations with high prevalence of obesity, provide a unique genetically enriched material in quest of new genes/variants influencing energy balance.

Diabetes is now a pandemic disease. Moreover, a large number of people with prediabetes are at risk for developing frank diabetes worldwide. Both type 1 and type 2 diabetes increase the risk of atherosclerotic cardiovascular disease (CVD). Even with statin treatment to lower LDL cholesterol, patients with diabetes have a high residual CVD risk. Factors mediating the residual risk are incompletely characterized. An attractive hypothesis is that remnant lipoprotein particles (RLPs), derived by lipolysis from VLDL and chylomicrons, contribute to this residual risk. RLPs constitute a heterogeneous population of lipoprotein particles, varying markedly in size and composition. Although a universally accepted definition is lacking, for the purpose of this review we define RLPs as postlipolytic partially triglyceride-depleted particles derived from chylomicrons and VLDL that are relatively enriched in cholesteryl esters and apolipoprotein (apo)E. RLPs derived from chylomicrons contain apoB48, while those derived from VLDL contain apoB100. Clarity as to the role of RLPs in CVD risk is hampered by lack of a widely accepted definition and a paucity of adequate methods for their accurate and precise quantification. New specific methods for RLP quantification would greatly improve our understanding of their biology and role in promoting atherosclerosis in diabetes and other disorders.

There has been an outpouring of grief following the death of legendary Jamaican singer Millicent Dolly May Small, popularly known as Millie Small. She died in the United Kingdom today at the age of 73 after suffering a stroke. The voice...

It is definitely a make-or-break season for those trying to balance career and COVID-19 at home. For some, it is the ideal time to reconnect with themselves, family members and get creative with work. While with others, the cookie crumbles and they...

Katalin Susztak
Jan 1, 2006; 55:225-233
Complications

Mariano J Garcia
Feb 1, 1974; 23:105-111
Original Contribution

Joachim Spranger
Mar 1, 2003; 52:812-817
Pathophysiology

Alexandra E. Butler
Jan 1, 2003; 52:102-110
Islet Studies

One of the most rapidly aging societies in the world, Japan is looking to immigration to address increased labor shortages—albeit slowly and largely without public debate. This country profile offers a brief overview of Japan’s migration history and examines the current immigration system, in particular policies and programs to bring in foreign workers, particularly on a temporary basis.

With nearly 1.4 million internally displaced persons (IDPs), Ukraine is home to one of the largest IDP populations in the world. Five years after Russia's annexation of Crimea, displaced Ukrainians continue to face challenges related to national identity, social cohesion, and political participation. While the Ukrainian government has had some success integrating IDPs, the conflict’s end remains uncertain, and many are unlikely to return to their communities of origin no matter the outcome.

OBJECTIVE

To improve outcomes of patients with adult type 2 diabetes by decreasing HbA_1c undertesting, reducing the proportion of patients with poor glycemic control, and lowering mean HbA_1c levels using a quality improvement (QI) program.

Edward A. Chow
Jul 1, 2012; 30:130-133
Diabetes Advocacy

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is associated with dyslipidemia, but the detailed alterations in lipid species preceding the disease are largely unknown. We aimed to identify plasma lipids associated with development of T2DM and investigate their associations with lifestyle.

OBJECTIVE

To analyze the differences in health care costs according to glycemic control in people with type 2 diabetes.

OBJECTIVE

To assess the contemporaneous prevalence of diabetic peripheral neuropathy (DPN) in people with type 1 diabetes (T1D) in Scotland and study its cross-sectional association with risk factors and other diabetic complications.

Henry N Ginsberg
Sep 1, 1991; 14:839-855
Diet and Diabetes

Kalevi Pyörälä
Mar 1, 1979; 2:131-141
Proceedings of the Kroc Foundation International Conference on Epidemiology of Diabetes and its Macrovascular Complications

Johanna M Mooy
Sep 1, 1995; 18:1270-1273
Short Report

OBJECTIVE

To investigate the association of the cardiovascular risk factor lipoprotein (Lp)(a) and vascular complications in patients with type 1 diabetes.

OBJECTIVE

To determine the risk of cardiovascular disease (CVD), microvascular complications, and mortality in patients with type 2 diabetes who subsequently develop obstructive sleep apnea (OSA) compared with patients with type 2 diabetes without a diagnosis of OSA.

OBJECTIVE

In patients with type 2 diabetes (T2D) and critical limb ischemia (CLI), migration of circulating CD34⁺ cells predicted cardiovascular mortality at 18 months after revascularization. This study aimed to provide long-term validation and mechanistic understanding of the biomarker.

The eligibility criteria for special education services is black and white. (I'm not talking about the color of skin.) Either the student fits the criteria or does not fit the criteria. The committee comes together with all the test data and then reviews the criteria for each disability. Either the student is eligible or not. They meet the criteria or they do not meet the criteria. Sounds easy, right? The kids who obviously fit the criteria easily qualify for special education services. The kids who clearly do not fit criteria for special education do not qualify for special education services. It should just be that easy. Sometimes it is.

I've been in the field long enough to see that eligibility is not always this magical process that determines special education from regular education. Sometimes eligibility decisions are a nightmare. What about all the gray kids that aren't clearly black or white?! For some kids, determining if they meet the criteria is tough. The black and white criteria makes it difficult to know what to do for the gray kids. The most difficult eligibility meetings are the ones where some members feel the student meets criteria and other members do not. These can lead to heated discussions. There are sometimes different ways to look at data and opinions of how to look at it may vary. Remember that the real issue the student who is cared about by school staff and especially parents which makes the decision emotional. It can be hard to be objective at times. It is not uncommon to hear "but they need it," even when the data does not support it.

There are kids who qualify for special education services at one point, then are found ineligible at another time. Sometimes this happens because the student has made improvements and no longer requires special education services to be successful. Other times this happens because criteria has changed, the criteria is slightly different in a new different school system, or because test data is slightly different after a few years. In my opinion, this is when the system and criteria fails. I'd like to see ways to address the students who at one time fit the criteria, no longer fit criteria, but still require services.

Why is the criteria so rigid? The main reason is because special education is funded by the government and they keep a tight reign on eligibility criteria. School staff is pressured by the administration, who is pressured by the State, who is pressured by the Federal government. There is a call for identification to be accurate to ensure that funds are properly spent. The only way the government can determine if the funds are being used appropriately is to enforce that schools are using clear criteria guidelines for identification.

All that being said, I believe in the process (for the most part). However, it's created by humans meaning there will be errors. If I had a say, I'd make some changes. I do believe there needs to be criteria. No matter who sets the criteria there will always be those gray kids that are just right on the border of eligible or not eligible. The worst mistake that can be made in my opinion is telling a family that the child has a disability when in fact the child does not. The child grows up with the belief that he or she has a disabling condition, when that could have been prevented. Disability identification can be life changing for a person. That is why I believe we need criteria. A strong opinion by a teacher or parent that "she needs it" is not enough data for me to look a child and say they are struggling because of a disability.

Want to learn more about the eligibility process?
Eligibility Process FAQ
What every parent needs to know about the referral process
Ineligible for special education

2017 saw the introduction of several bills—two of them by Senate Republicans in the weeks following the Trump administration’s announcement that it would terminate the Deferred Action for Childhood Arrivals (DACA) program—that would provide a pathway to conditional and then legal permanent residence to unauthorized immigrants brought to the United States as children, if they meet a range of educational, professional, and other criteria.

This fact sheet and accompanying interactive data tools provide characteristics of the estimated 11.3 million unauthorized immigrants in the United States, using a unique MPI methodology that assigns legal status to U.S. Census Bureau data. The fact sheet and tools offer statistics on these immigrants’ origins, U.S. destinations, educational attainment, English proficiency, employment, income, home ownership, and more.

Testimony of Marc Rosenblum before the Senate Committee on Homeland Security and Governmental Affairs for the March 26, 2015 hearing on the characteristics of unauthorized immigrants in the United States and how to address future flows.

Pennsylvania Avenue, would placing some of them in zoos be unethical? Would they be considered human enough to receive human rights?

In many recent European and U.S. elections, candidates touting nativist populist and anti-immigrant platforms have enjoyed rising support. As populism moves from the fringes into the mainstream, this report takes stock of the economic and social forces driving its rise, the diverse ways populists are influencing immigration policymaking, and what it will take to build a new center around immigration and integration issues.

Since regaining its independence in 1989, the Czech Republic has transformed from a country of emigration to one of rising immigration, amid growing labor market needs. Even as Czechia received few asylum seekers during the 2015-16 European migration crisis, the country has taken a harder line on immigration, and public opinion and political stances have grown more negative towards immigrants and refugees.

The Houston metro area, home to 1.6 million immigrants, is diverse and rapidly growing. This report sketches the area's immigrant population, examining top origin countries, key socioeconomic measures, and more. It also explores how Hurricane Harvey affected the immigrant population, and how national policy changes under the Trump administration are being felt locally, including by DACA recipients and asylum seekers.

Dual Language Learners (DLLs) are a growing segment of the Minnesota young child population, and a particularly "superdiverse" one with myriad origins, cultures, and languages—a new reality other states and communities will face. Drawing on interviews with policymakers and service providers, as well as analysis of census data, this report examines what this incredible diversity means for the state’s early childhood policies and programs.

The future of the Deferred Action for Childhood Arrivals (DACA) program is uncertain, amid skepticism from the Trump administration about its merits and the promise of legal challenge from ten state attorneys general. This issue brief presents a profile of young adults eligible for DACA in terms of their educational attainment and labor force participation, as well as what is at stake should the program be terminated.