Ether lipid biosynthesis promotes lifespan extension and enables diverse pro-longevity paradigms in Caenorhabditis elegans.

Biguanides, including the world's most prescribed drug for type 2 diabetes, metformin, not only lower blood sugar, but also promote longevity in preclinical models. Epidemiologic studies in humans parallel these findings, indicating favorable effects of metformin on longevity and on reducing the incidence and morbidity associated with aging-related diseases. Despite this promise, the full spectrum of molecular effectors responsible for these health benefits remains elusive. Through unbiased screening in Caenorhabditis elegans, we uncovered a role for genes necessary for ether lipid biosynthesis in the favorable effects of biguanides. We demonstrate that biguanides prompt lifespan extension by stimulating ether lipid biogenesis. Loss of the ether lipid biosynthetic machinery also mitigates lifespan extension attributable to dietary restriction, target of rapamycin (TOR) inhibition, and mitochondrial electron transport chain inhibition. A possible mechanistic explanation for this finding is that ether lipids are required for activation of longevity-promoting, metabolic stress defenses downstream of the conserved transcription factor skn-1/Nrf. In alignment with these findings, overexpression of a single, key, ether lipid biosynthetic enzyme, fard-1/FAR1, is sufficient to promote lifespan extension. These findings illuminate the ether lipid biosynthetic machinery as a novel therapeutic target to promote healthy aging.

Metformin is the drug most prescribed to treat type 2 diabetes around the world and has been in clinical use since 1950. The drug belongs to a family of compounds known as biguanides which reduce blood sugar, making them an effective treatment against type 2 diabetes. More recently, biguanides have been found to have other health benefits, including limiting the growth of various cancer cells and improving the lifespan and long-term health of several model organisms. Epidemiologic studies also suggest that metformin may increase the lifespan of humans and reduce the incidence of age-related illnesses such as cardiovascular disease, cancer and dementia. Given the safety and effectiveness of metformin, understanding how it exerts these desirable effects may allow scientists to discover new mechanisms to promote healthy aging. The roundworm Caenorhabditis elegans is an ideal organism for studying the lifespan-extending effects of metformin. It has an average lifespan of two weeks, a genome that is relatively easy to manipulate, and a transparent body that enables scientists to observe cellular and molecular events in living worms. To discover the genes that enable metformin's lifespan-extending properties, Cedillo, Ahsan et al. systematically switched off the expression of about 1,000 genes involved in C. elegans metabolism. They then screened for genes which impaired the action of biguanides when inactivated. This ultimately led to the identification of a set of genes involved in promoting a longer lifespan. Cedillo, Ahsan et al. then evaluated how these genes impacted other well-described pathways involved in longevity and stress responses. The analysis indicated that a biguanide drug called phenformin (which is similar to metformin) increases the synthesis of ether lipids, a class of fats that are critical components of cellular membranes. Indeed, genetically mutating the three major enzymes required for ether lipid production stopped the biguanide from extending the worms' lifespans. Critically, inactivating these genes also prevented lifespan extension through other known strategies, such as dietary restriction and inhibiting the cellular organelle responsible for producing energy. Cedillo, Ahsan et al. also showed that increasing ether lipid production alters the activity of a well-known longevity and stress response factor called SKN-1, and this change alone is enough to extend the lifespan of worms. These findings suggest that promoting the production of ether lipids could lead to healthier aging. However, further studies, including clinical trials, will be required to determine whether this is a viable approach to promote longevity and health in humans.

Lipid droplets and peroxisomes are co-regulated to drive lifespan extension in response to mono-unsaturated fatty acids.

Dietary mono-unsaturated fatty acids (MUFAs) are linked to longevity in several species. But the mechanisms by which MUFAs extend lifespan remain unclear. Here we show that an organelle network involving lipid droplets and peroxisomes is critical for MUFA-induced longevity in Caenorhabditis elegans. MUFAs upregulate the number of lipid droplets in fat storage tissues. Increased lipid droplet number is necessary for MUFA-induced longevity and predicts remaining lifespan. Lipidomics datasets reveal that MUFAs also modify the ratio of membrane lipids and ether lipids-a signature associated with decreased lipid oxidation. In agreement with this, MUFAs decrease lipid oxidation in middle-aged individuals. Intriguingly, MUFAs upregulate not only lipid droplet number but also peroxisome number. A targeted screen identifies genes involved in the co-regulation of lipid droplets and peroxisomes, and reveals that induction of both organelles is optimal for longevity. Our study uncovers an organelle network involved in lipid homeostasis and lifespan regulation, opening new avenues for interventions to delay aging.

Tenecteplase Versus Alteplase for Acute Stroke: Mortality and Bleeding Complications.

STUDY OBJECTIVE: Intravenous thrombolysis with alteplase has been the foundation of initial treatment of acute ischemic stroke for several decades. Tenecteplase is a thrombolytic agent that offers logistical advantages in cost and administration relative to alteplase. There is evidence that tenecteplase has at least similar efficacy and safety outcomes compared with alteplase for stroke. In this study, we compared tenecteplase versus alteplase for acute stroke in a large retrospective US database (TriNetX) regarding the following 3 outcomes: (1) mortality, (2) intracranial hemorrhage, and (3) the need for acute blood transfusions. METHODS: In this retrospective study using the US cohort of 54 academic medical centers/health care organizations in the TriNetX database, we identified 3,432 patients treated with tenecteplase and 55,894 patients treated with alteplase for stroke after January 1, 2012. Propensity score matching was performed on basic demographic information and 7 previous clinical diagnostic groups, resulting in a total of 6,864 patients with acute stroke evenly matched between groups. Mortality rates, the frequency of intracranial hemorrhage, and blood transfusions (as a marker of significant blood loss) were recorded for each group over the ensuing 7- and 30-day periods. Secondary subgroup analyses were conducted on a cohort treated from 2021 to 2022 in an attempt to determine whether temporal differences in acute ischemic stroke treatment would alter the results. RESULTS: Patients treated with tenecteplase had a significantly lower mortality rate (8.2% versus 9.8%; risk ratio [RR], 0.832) and lower risk of major bleeding as measured by the frequency of blood transfusions (0.3% versus 1.4%; RR, 0.207) than alteplase at 30 days after thrombolysis for stroke. In the larger 10-year data set of patients with stroke treated after January 1, 2012, patients receiving tenecteplase were not found to have a statistically different incidence of intracranial hemorrhage (3.5% versus 3.0%; RR, 1.185) at 30 days after the administration of the thrombolytic agents in patients. However, a subgroup analysis of 2,216 evenly matched patients with stroke treated from 2021 to 2022 demonstrated notably better survival and statistically lower rates of intracranial hemorrhage than the alteplase group. CONCLUSION: In our large retrospective multicenter study using real-world evidence from large health care organizations, tenecteplase for the treatment of acute stroke demonstrated a lower mortality rate, decreased intracranial hemorrhage, and less significant blood loss. The favorable mortality and safety profiles observed in this large study, taken together with previous randomized controlled trial data and operational advantages in rapid dosing and cost-effectiveness, all support the preferential use of tenecteplase in patients with ischemic stroke.

PrEP policy implementation gaps and opportunities in Latin America and the Caribbean: a scoping review.

Background: Pre-exposure prophylaxis (PrEP) is an important tool for HIV prevention in Latin America and the Caribbean (LAC). Yet, little is known about the PrEP policies landscape in the region. Addressing this gap, this scoping review assessed current PrEP policies throughout LAC to better understand existing PrEP implementation gaps and identify opportunities to improve access. Methods: We conducted a scoping review, using a modified PRISMA extension, through 28 July 2022, to identify country-level PrEP policies. Data were collected in English, Spanish, French, and Portuguese utilizing online platforms for screening and data extraction (Google Forms, Zotero, and Excel). Extracted data were divided by data source, including country-level government policies, gray literature, and peer-reviewed literature, with at least one full-text reviewer and data extractor per publication. An iterative summative content analysis was performed to compare and interpret themes across phases and data sources. Results: Of the 33 countries in LAC, 22 (67%) had policies approving daily oral PrEP for HIV prevention, which outlined specific key populations, including men who have sex with men, transgender women, sex workers, and serodiscordant couples. Generic tenofovir disoproxil fumarate/emtricitabine has been approved in 15 of the 33 countries, and 13 of the 33 countries have incorporated PrEP into their public health system. No countries were found to have approved cabotegravir. Costing data were reported by only one country, Ecuador, in its national health ministry guidelines. Findings also document a lag between the media/gray-literature announcement of PrEP and implementation of policies. Conclusion: Findings underscore significant advances in PrEP policies in the region and signal opportunities for greater PrEP implementation. Since 2017, an increasing number of countries have begun to provide PrEP to communities at heightened need, although significant gaps remain. Policy approval is a key step to further increasing access to PrEP in LAC, necessary to reduce the burden of HIV in LAC, specifically among marginalized populations.

Riboflavin depletion promotes longevity and metabolic hormesis in Caenorhabditis elegans.

Riboflavin is an essential cofactor in many enzymatic processes and in the production of flavin adenine dinucleotide (FAD). Here, we report that the partial depletion of riboflavin through knockdown of the C. elegans riboflavin transporter 1 (rft-1) promotes metabolic health by reducing intracellular flavin concentrations. Knockdown of rft-1 significantly increases lifespan in a manner dependent upon AMP-activated protein kinase (AMPK)/aak-2, the mitochondrial unfolded protein response, and FOXO/daf-16. Riboflavin depletion promotes altered energetic and redox states and increases adiposity, independent of lifespan genetic dependencies. Riboflavin-depleted animals also exhibit the activation of caloric restriction reporters without any reduction in caloric intake. Our findings indicate that riboflavin depletion activates an integrated hormetic response that promotes lifespan and healthspan in C. elegans.

16p12.1 Deletion Orthologs are Expressed in Motile Neural Crest Cells and are Important for Regulating Craniofacial Development in Xenopus laevis.

Copy number variants (CNVs) associated with neurodevelopmental disorders are characterized by extensive phenotypic heterogeneity. In particular, one CNV was identified in a subset of children clinically diagnosed with intellectual disabilities (ID) that results in a hemizygous deletion of multiple genes at chromosome 16p12.1. In addition to ID, individuals with this deletion display a variety of symptoms including microcephaly, seizures, cardiac defects, and growth retardation. Moreover, patients also manifest severe craniofacial abnormalities, such as micrognathia, cartilage malformation of the ears and nose, and facial asymmetries; however, the function of the genes within the 16p12.1 region have not been studied in the context of vertebrate craniofacial development. The craniofacial tissues affected in patients with this deletion all derive from the same embryonic precursor, the cranial neural crest, leading to the hypothesis that one or more of the 16p12.1 genes may be involved in regulating neural crest cell (NCC)-related processes. To examine this, we characterized the developmental role of the 16p12.1-affected gene orthologs, polr3e, mosmo, uqcrc2, and cdr2, during craniofacial morphogenesis in the vertebrate model system, Xenopus laevis. While the currently-known cellular functions of these genes are diverse, we find that they share similar expression patterns along the neural tube, pharyngeal arches, and later craniofacial structures. As these genes show co-expression in the pharyngeal arches where NCCs reside, we sought to elucidate the effect of individual gene depletion on craniofacial development and NCC migration. We find that reduction of several 16p12.1 genes significantly disrupts craniofacial and cartilage formation, pharyngeal arch migration, as well as NCC specification and motility. Thus, we have determined that some of these genes play an essential role during vertebrate craniofacial patterning by regulating specific processes during NCC development, which may be an underlying mechanism contributing to the craniofacial defects associated with the 16p12.1 deletion.

Matrix Stiffness Modulates Patient-Derived Glioblastoma Cell Fates in Three-Dimensional Hydrogels.

Cancer progression is known to be accompanied by changes in tissue stiffness. Previous studies have primarily employed immortalized cell lines and 2D hydrogel substrates, which do not recapitulate the 3D tumor niche. How matrix stiffness affects patient-derived cancer cell fate in 3D remains unclear. In this study, we report a matrix metalloproteinase-degradable poly(ethylene-glycol)-based hydrogel platform with brain-mimicking biochemical cues and tunable stiffness (40-26,600 Pa) for 3D culture of patient-derived glioblastoma xenograft (PDTX GBM) cells. Our results demonstrate that decreasing hydrogel stiffness enhanced PDTX GBM cell proliferation, and hydrogels with stiffness 240 Pa and below supported robust PDTX GBM cell spreading in 3D. PDTX GBM cells encapsulated in hydrogels demonstrated higher drug resistance than 2D control, and increasing hydrogel stiffness further enhanced drug resistance. Such 3D hydrogel platforms may provide a valuable tool for mechanistic studies of the role of niche cues in modulating cancer progression for different cancer types.

Social Integration and Community Health Participation of Elderly Men in Peri-Urban Ecuador.

Background: Social integration is an essential element to the maintenance of health and well-being in elderly populations. In the Cumbaya Valley of Quito, Ecuador, community health clinics sponsor social clubs for specific populations to address this important aspect of health. Men, who tend to be less socially integrated than women, are largely absent from these programs. Objective: This paper investigates the quality and extent of men's social integration in the Cumbaya Valley of Quito to understand why men are less likely to attend the community health center clubs and to develop ideas for increasing male participation, which may differ from current methods. Methods: A composite survey was used to interview 100 men over the age of 40 to collect data on their social health and information regarding their interaction with community health center clubs and other local social groups. Findings: Social integration scores were varied, with some men having high social scores and others having low scores. Men generally had greater access to affectionate and tangible support but lower access to emotional support and positive social interaction. Men spend far more social time with their families and much less with friends and neighbors. Regression analysis revealed that social scores have a relationship with age and education. Qualitative results suggest gendered expectations of men in the community have negatively impacted their willingness to engage in community health groups. Participants also provided suggestions, including specific sports, gardening, and meal distribution, to promote male participation. Conclusion: There is a strong need to increase services, strategies, and programs that address the lack of social integration experienced by men. This paper presents the particular role community clinics can play in increasing the social well-being of its male patients.

Humanity's Best Friend: A Dog-Centric Approach to Addressing Global Challenges.

No other animal has a closer mutualistic relationship with humans than the dog (Canis familiaris). Domesticated from the Eurasian grey wolf (Canis lupus), dogs have evolved alongside humans over millennia in a relationship that has transformed dogs and the environments in which humans and dogs have co-inhabited. The story of the dog is the story of recent humanity, in all its biological and cultural complexity. By exploring human-dog-environment interactions throughout time and space, it is possible not only to understand vital elements of global history, but also to critically assess our present-day relationship with the natural world, and to begin to mitigate future global challenges. In this paper, co-authored by researchers from across the natural and social sciences, arts and humanities, we argue that a dog-centric approach provides a new model for future academic enquiry and engagement with both the public and the global environmental agenda.

Exposure to bisphenol A and diabetes risk in Mexican women.

Bisphenol A (BPA) is an endocrine-disrupting chemical widely used in the production of polycarbonate plastics and epoxy resins, which has been previously linked to diabetes among non-Hispanic populations. As part of a case control study for breast cancer, only controls with BPA information were included in this report. The final sample size comprises 70 self-reported diabetics and 334 non-diabetics. Urinary free bisphenol A (BPA-F) (µg/L) was determined by solid-phase extraction and HPLC/FLD analysis. Logistic regression models were used to evaluate the association between BPA-F and self-reported diabetes. After adjusting by age, urinary BPA-F (4.06-224.53 µg/g creatinine) was associated with diabetes exposure (OR = 1.85; 95% CI 1.04, 3.28) compared with women in the reference category (0.67-4.05 µg/g creatinine). BPA may be an environmental cofactor of diabetes. More studies are needed to confirm this result, especially in Hispanic populations.

Structurally simple complexes of CO2.

The ability to bind CO2 through the formation of low-energy, easily-broken, bonds could prove invaluable in a variety of chemical contexts. For example, weak bonds to CO2 would greatly decrease the cost of the energy-intensive sorbent-regeneration step common to most carbon capture technologies. Furthermore, exploration of this field could lead to the discovery of novel CO2 chemistry. Reduction of complexed carbon dioxide might generate chemical feedstocks for the preparation of value-added products, particularly transportation fuels or fuel precursors. Implementation on a large scale could help to drastically reduce CO2 concentrations in the atmosphere. However, literature examples of weakly bonded complexes of CO2 are relatively few and true coordination complexes to a 'naked' CO2 fragment are nearly unheard of. In this review article, a variety of complexes of CO2 featuring diverse binding modes and reactivity will be examined. Topics covered include: (A) inclusion complexes of CO2 in porous materials. (B) Zwitterionic carbamates produced from the reaction of CO2 with polyamines. (C) Carbamate salts produced from reaction of CO2 with two equivalents of an amine. (D) Insertion products of CO2 into acid-base adducts (e.g., metal complexes). (E) Lewis acid-base activated CO2, such as frustrated Lewis pair complexes. (F) Simple base-CO2 adducts, wherein the base-CO2 bond is the only interaction formed. Complexes in the last category are of particular interest, and include imidazol-2-carboxylates (N-heterocyclic carbene adducts of CO2) as well as a few other examples that lie outside NHC chemistry.

A simple complex on the verge of breakdown: isolation of the elusive cyanoformate ion.

Why does cyanide not react destructively with the proximal iron center at the active site of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase, an enzyme central to the biosynthesis of ethylene in plants? It has long been postulated that the cyanoformate anion, [NCCO2](-), forms and then decomposes to carbon dioxide and cyanide during this process. We have now isolated and crystallographically characterized this elusive anion as its tetraphenylphosphonium salt. Theoretical calculations show that cyanoformate has a very weak C-C bond and that it is thermodynamically stable only in low dielectric media. Solution stability studies have substantiated the latter result. We propose that cyanoformate shuttles the potentially toxic cyanide away from the low dielectric active site of ACC oxidase before breaking down in the higher dielectric medium of the cell.

NH/PH isomerization and a Lewis pair for carbon dioxide capture.

Bis(di-i-propylphosphino)amine 1 reacts with B(C6F5)3 to form an adduct with concomitant N/P H-isomerization. This species reacts smoothly with carbon dioxide. An attempt to prepare an anionic derivative resulted in the formation of a novel heterocycle derived from the PNP ligand and B(C6F5)3.

Ionic liquids and acid gas capture: water and oxygen as confounding factors.

Amines dissolved in ionic liquids react rapidly with SO(2) to produce new materials. Compounds related to the stepwise conversion of SO(2) to sulfite and sulfate salts have been isolated. Trapping SO(2) in the form of the sulfite anion does not change the oxidation state of sulfur and should maintain the reversibility of the capture system.