27-GAUGE PARS PLANA/PLICATA VITRECTOMY FOR PEDIATRIC VITREORETINAL SURGERY.

PURPOSE: To report on the feasibility of 27-gauge (G) vitrectomy for pediatric patients. METHODS: This study is an international, multicenter, retrospective, interventional case series. Participants were patients 17 years or younger who underwent 27-G vitrectomy for various indications. RESULTS: The records of 56 eyes from 47 patients were reviewed. Mean age was 5.7 ± 5.2 years. Diagnoses included retinopathy of prematurity (Stages 3 with vitreous hemorrhage, 4A, 4B, and 5), Terson's syndrome, traumatic macular hole, posterior capsular opacification, endophthalmitis, and others. Instruments used were the 27-G infusion, 27-G vitreous cutter, 27-G light pipe, and 27-G internal limiting membrane forceps. Instrument bending was noted in one (1.8%) case. There were no cases with intraoperative complications, infusion issues, or postoperative endophthalmitis. There were 67/145 (46%) sclerotomies that required suturing, of which most (51/145) were sutured out of precaution. There were four cases (7.1%) that required conversion to a larger gauge and three cases (5.3%) that developed postoperative hypotony. Mean visual acuity improved from logarithm of the minimum angle of resolution 1.32 (20/420) to 0.72 (20/105), after a mean follow-up of 125.1 days (P = 0.01). Anatomic success was achieved in 96.4% of eyes after a single surgery. CONCLUSION: Twenty-seven-gauge vitrectomy was safe and feasible in selected pediatric vitreoretinopathies. Further studies are warranted to examine indications and outcomes.

The rumen eukaryotome is a source of novel antimicrobial peptides with therapeutic potential.

BACKGROUND: The rise of microbial antibiotic resistance is a leading threat to the health of the human population. As such, finding new approaches to tackle these microbes, including development of novel antibiotics is vital. RESULTS: In this study, we mined a rumen eukaryotic metatranscriptomic library for novel Antimicrobial peptides (AMPs) using computational approaches and thereafter characterised the therapeutic potential of the AMPs. We identified a total of 208 potentially novel AMPs from the ruminal eukaryotome, and characterised one of those, namely Lubelisin. Lubelisin (GIVAWFWRLAR) is an α-helical peptide, 11 amino acid long with theoretical molecular weight of 1373.76 D. In the presence of Lubelisin, strains of methicillin-resistant Staphylococcus aureus (MRSA) USA300 and EMRSA-15 were killed within 30 min of exposure with ≥103 and 104 CFU/mL reduction in viable cells respectively. Cytotoxicity of Lubelisin against both human and sheep erythrocytes was low resulting in a therapeutic index of 0.43. Membrane permeabilisation assays using propidium iodide alongside transmission electron microscopy revealed that cytoplasmic membrane damage may contribute to the antimicrobial activities of Lubelisin. CONCLUSIONS: We demonstrate that the rumen eukaryotome is a viable source for the discovery of antimicrobial molecules for the treatment of bacterial infections and further development of these may provide part of the potential solution to the ongoing problem of antimicrobial resistance. The role of these AMPs in the ecological warfare within the rumen is also currently unknown.

PHOSPHO1 is a skeletal regulator of insulin resistance and obesity.

BACKGROUND: The classical functions of the skeleton encompass locomotion, protection and mineral homeostasis. However, cell-specific gene deletions in the mouse and human genetic studies have identified the skeleton as a key endocrine regulator of metabolism. The bone-specific phosphatase, Phosphatase, Orphan 1 (PHOSPHO1), which is indispensable for bone mineralisation, has been recently implicated in the regulation of energy metabolism in humans, but its role in systemic metabolism remains unclear. Here, we probe the mechanism underlying metabolic regulation by analysing Phospho1 mutant mice. RESULTS: Phospho1-/- mice exhibited improved basal glucose homeostasis and resisted high-fat-diet-induced weight gain and diabetes. The metabolic protection in Phospho1-/- mice was manifested in the absence of altered levels of osteocalcin. Osteoblasts isolated from Phospho1-/- mice were enriched for genes associated with energy metabolism and diabetes; Phospho1 both directly and indirectly interacted with genes associated with glucose transport and insulin receptor signalling. Canonical thermogenesis via brown adipose tissue did not underlie the metabolic protection observed in adult Phospho1-/- mice. However, the decreased serum choline levels in Phospho1-/- mice were normalised by feeding a 2% choline rich diet resulting in a normalisation in insulin sensitivity and fat mass. CONCLUSION: We show that mice lacking the bone mineralisation enzyme PHOSPHO1 exhibit improved basal glucose homeostasis and resist high-fat-diet-induced weight gain and diabetes. This study identifies PHOSPHO1 as a potential bone-derived therapeutic target for the treatment of obesity and diabetes.

ETIOLOGY AND CLINICAL CHARACTERISTICS OF MACULAR EDEMA IN PATIENTS WITH FAMILIAL EXUDATIVE VITREORETINOPATHY.

PURPOSE: To describe the etiology and clinical characteristics of macular edema (ME) in patients with familial exudative vitreoretinopathy. METHODS: Observational, retrospective case series of 30 patients (34 eyes) with ME and familial exudative vitreoretinopathy who underwent spectral-domain optical coherence tomography imaging between 2009 and 2016. Baseline and follow-up optical coherence tomographies were correlated with color fundus photography and fluorescein angiography. RESULTS: The average age was 20.6 years (6.6-68.7). Eighteen eyes exhibited cystoid ME (52.9%), 14 noncystoid ME (41.2%), and 2 eyes (5.9%) with both. Macular edema was foveal in 52.9% (n = 18). Eighteen of 24 eyes (64.3%) with an available fluorescein angiography showed leakage from ME. The most common structural feature was posterior hyaloidal organization/contraction (n = 15). Sixteen eyes were treated with topical or intravitreal steroids (n = 6), intravitreal anti-vascular endothelial growth factor (n = 3), or pars plana vitrectomy with membrane stripping (n = 7). There was no difference between mean preoperative and postoperative LogMAR visual acuity (0.63 [20/85] vs. 0.87 [20/148], P = 0.35) after vitrectomy despite a statistical improvement in the mean central foveal thickness (596 mm vs. 303 mm, P = 0.04). CONCLUSION: Macular edema in familial exudative vitreoretinopathy occurs most commonly because of traction. Vitrectomy is effective for relieving tractional forces with anatomical improvement.

PROGRESSIVE RETINAL DETACHMENT IN INFANTS WITH RETINOPATHY OF PREMATURITY TREATED WITH INTRAVITREAL BEVACIZUMAB OR RANIBIZUMAB.

PURPOSE: Fibrovascular contraction and tractional retinal detachment (TRD) are recognized complications associated with the use of anti-vascular endothelial growth factor agents in vasoproliferative vitreoretinopathies. The authors characterize TRDs that developed after intravitreal bevacizumab or ranibizumab therapy for vascularly active retinopathy of prematurity. METHODS: This is an international, multicenter, interventional, retrospective, case series. Thirty-five eyes from 23 infants were included. Inclusion required anti-vascular endothelial growth factor treatment of Type 1 retinopathy of prematurity with progression to TRD. RESULTS: Mean gestational age was 26 ± 2 weeks, and mean birth weight was 873 ± 341 g. Mean postmenstrual age on the day of injection was 35 ± 2 weeks. Retinal detachment was noted a mean of 70 days (median, 34; range, 4-335) after injection. Eleven percent detached within 1 week, 23% within 2 weeks, and 49% within 4 weeks. The highest stage of retinopathy of prematurity noted was 4A in 29%, 4B in 37%, and 5 in 34% of eyes. Time to RD negatively correlated with postmenstrual age at the time of injection (Rho = -0.54; P < 0.01). Three TRD configurations were observed: 1) conventional peripheral elevated ridge or volcano-shaped Stage 5 detachment, 2) midperipheral detachment with tight circumferential vectors, and 3) very posterior detachment with prepapillary contraction. Full or partial reattachment was achieved with surgical intervention in 86% of eyes. CONCLUSION: Progressive atypical TRD may occur after anti-vascular endothelial growth factor injections for retinopathy of prematurity. The configuration of the detachment varies with the extent of primary retinal vascularization present at the time of treatment.

THE CUTTING EDGE OF RETINOPATHY OF PREMATURITY CARE: Expanding the Boundaries of Diagnosis and Treatment.

PURPOSE: To discuss the latest advances and controversies in the diagnosis and care of infants with retinopathy of prematurity (ROP). METHODS: Literature review. RESULTS: Retinopathy of prematurity remains a major global issue. Industrialized nations now treat profoundly premature infants with posterior and aggressive disease, and middle-income nations are experiencing ROP epidemics. Remote digital imaging may address the decreasing ratio of ROP providers to premature infants, in addition to improving patient care. Widefield angiography, optical coherence tomography, and the Wnt signaling pathway have provided new insights into ROP pathogenesis. Anti-vascular endothelial growth factor treatment is increasing in popularity, but the dearth of information to guide dosing, unpredictable reactivation, persistent vascular abnormalities, the "crunch" phenomenon, and the presently unknown effects of systemic vascular endothelial growth factor suppression remain issues to continue investigating. Neurodevelopmental delay has been raised as a potential consequence, but the evidence currently is weak. Vitrectomy is the treatment of choice for Stages 4 and 5. Illumination techniques, ab interno incisions, plasmin-assisted vitrectomy, staged surgery in the interest of corneal clearing for advanced Stage 5, and immediate sequential bilateral vitreoretinal surgery, are useful techniques. CONCLUSION: We are making progress in ROP management. Our goal as clinicians is to continue expanding the boundaries of our abilities to keep this blinding disease in check globally.

MICROBIOLOGIC SPECTRUM AND VISUAL OUTCOMES OF ACUTE-ONSET ENDOPHTHALMITIS UNDERGOING THERAPEUTIC PARS PLANA VITRECTOMY.

PURPOSE: To report the clinical presentation, microbiologic spectrum, and visual outcomes associated with acute-onset infectious endophthalmitis undergoing therapeutic pars plana vitrectomy. METHODS: Multicenter interventional retrospective noncomparative consecutive case series. Billing records were reviewed to identify all charts for patients undergoing pars plana vitrectomy within 14 days of diagnosis of acute-onset infectious endophthalmitis over a 4-year period at 5 large tertiary referral retina practices. Statistical analysis was performed to assess for factors associated with visual outcomes. RESULTS: Seventy patients were identified. The most common clinical setting was postcataract surgery (n = 20). Only 3 patients (4.3%) presented with 20/400 or better visual acuity (VA). Although most of the patients initially underwent vitreous tap and intravitreal antibiotic injection (n = 47, 67.1%), all patients eventually underwent pars plana vitrectomy within 14 days of presentation with 68.5% (48/70) of patients undergoing pars plana vitrectomy within 48 hours of presentation. Positive intraocular cultures were obtained in 56 patients (80%). The most common identified organism was Streptococcus sp (n = 19). Visual acuity at last follow-up was 20/400 or better in 19 patients (27.1%). Three patients underwent evisceration or enucleation (4.3%). Last recorded postoperative VA (mean LogMAR 1.99 ± 0.94, Snellen VA equivalent finger count) improved from presenting VA (mean LogMAR 2.37 ± 0.38, Snellen VA hand motions) (P ≤ 0.001). There was no statistically significant correlation between the underlying etiology or the timing of surgery with this VA outcome. CONCLUSION: Although less than one-third of patients achieved 20/400 or better VA, this VA often improved significantly from presenting VA.

PARS PLANA VITRECTOMY FOR LATE VITREORETINAL SEQUELAE OF INFECTIOUS ENDOPHTHALMITIS: Surgical Management and Outcomes.

PURPOSE: To report the visual acuity outcomes after pars plana vitrectomy for delayed vitreoretinal sequelae of infectious endophthalmitis. All eyes were initially treated with intravitreal antibiotics (Abx). METHODS: Multicenter, retrospective, consecutive case series. RESULTS: Forty-two eyes met the study criteria. The mean follow-up was 48 weeks (SD ± 61.8). Mean interval from Abx to pars plana vitrectomy was 13 weeks (SD ± 14.3, range 2-70). Indications for pars plana vitrectomy included vitreous opacities (VO) (n = 22), epiretinal membrane (n = 9), and retinal detachment (n = 11). LogMAR visual acuity improved from 1.87 (Snellen equivalent: 20/1,482) preoperatively to 1.35 (Snellen equivalent: 20/447) at final evaluation (P < 0.001). LogMAR visual acuity improved significantly for patients with vitreous opacities (P < 0.01) and retinal detachment (P = 0.02) but not for patients with epiretinal membranes (P = 0.08). CONCLUSION: Patients with infectious endophthalmitis can gain vision if they have a pars plana vitrectomy for delayed sequelae such as vitreous opacities or for retinal detachment.

Immediate Sequential Bilateral Pediatric Vitreoretinal Surgery: An International Multicenter Study.

PURPOSE: To determine the feasibility and safety of bilateral simultaneous vitreoretinal surgery in pediatric patients. DESIGN: International, multicenter, interventional, retrospective case series. PARTICIPANTS: Patients 17 years of age or younger from 24 centers worldwide who underwent immediate sequential bilateral vitreoretinal surgery (ISBVS)-defined as vitrectomy, scleral buckle, or lensectomy using the vitreous cutter-performed in both eyes sequentially during the same anesthesia session. METHODS: Clinical history, surgical details and indications, time under anesthesia, and intraoperative and postoperative ophthalmic and systemic adverse events were reviewed. MAIN OUTCOME MEASURES: Ocular and systemic adverse events. RESULTS: A total of 344 surgeries from 172 ISBVS procedures in 167 patients were included in the study. The mean age of the cohort was 1.3±2.6 years. Nonexclusive indications for ISBVS were rapidly progressive disease (74.6%), systemic morbidity placing the child at high anesthesia risk (76.0%), and residence remote from surgery location (30.2%). The most common diagnoses were retinopathy of prematurity (ROP; 72.7% [P < 0.01]; stage 3, 4.8%; stage 4A, 44.4%; stage 4B, 22.4%; stage 5, 26.4%), familial exudative vitreoretinopathy (7.0%), abusive head trauma (4.1%), persistent fetal vasculature (3.5%), congenital cataract (1.7%), posterior capsular opacification (1.7%), rhegmatogenous retinal detachment (1.7%), congenital X-linked retinoschisis (1.2%), Norrie disease (2.3%), and viral retinitis (1.2%). Mean surgical time was 143±59 minutes for both eyes. Higher ROP stage correlated with longer surgical time (P = 0.02). There were no reported intraoperative ocular complications. During the immediate postoperative period, 2 eyes from different patients demonstrated unilateral vitreous hemorrhage (0.6%). No cases of endophthalmitis, choroidal hemorrhage, or hypotony occurred. Mean total anesthesia time was 203±87 minutes. There were no cases of anesthesia-related death, malignant hyperthermia, anaphylaxis, or cardiac event. There was 1 case of reintubation (0.6%) and 1 case of prolonged oxygen desaturation (0.6%). Mean follow-up after surgery was 103 weeks, and anatomic success and globe salvage rates were 89.8% and 98.0%, respectively. CONCLUSIONS: This study found ISBVS to be a feasible and safe treatment paradigm for pediatric patients with bilateral vitreoretinal pathologic features when repeated general anesthesia is undesirable or impractical.

WIDE-FIELD IMAGING OF NONEXUDATIVE AND EXUDATIVE CONGENITAL X-LINKED RETINOSCHISIS.

PURPOSE: To describe wide-field imaging features of patients with congenital X-linked retinoschisis. METHODS: This is a retrospective nonconsecutive series of 36 eyes from 18 patients with congenital X-linked retinoschisis from 2008 to 2014. Wide-field color fundus photographs, optical coherence tomography images, and wide-field fluorescein angiography images were reviewed. Patients were classified to have either exudative or nonexudative retinoschisis based on the presence or absence of lipid exudates. RESULTS: Eleven eyes exhibited exudative retinoschisis (30%), whereas the remaining were nonexudative. Exudative disease occurred more commonly in older patients (14.4 vs. 4.0 years; P < 0.001). The most frequent location of exudation was the macula. Subretinal hemorrhage was present in 4 eyes (11%). Macular findings included an atypical foveal avascular zone in 7 eyes (19%) and submacular fibrosis or retinal folds in 6 eyes (17%). Peripheral characteristics included fibrosis or folds (11%), bridging vessels (8%), and vascular sheathing (8%). Thirteen of the 22 eyes (59%) demonstrated leakage on fluorescein angiography. CONCLUSION: Exudation may be more common in congenital X-linked retinoschisis than previously recognized. The presence of exudates with concurrent angiographic leakage suggests that exudation may be due to chronic vascular permeability and not solely caused by intraschisis hemorrhage, which has been classically described.

Tailored treatment options for patients with psoriatic arthritis and psoriasis: review of established and new biologic and small molecule therapies.

The diverse clinical picture of PsA suggests the need to identify suitable therapies to address the different combinations of clinical manifestations. This review aimed to classify the available biologic agents and new small molecule inhibitors (licensed and nonlicensed) based on their proven efficacy in treating different clinical manifestations associated with psoriasis and PsA. This review presents the level of evidence of efficacy of different biologic treatments and small molecule inhibitors for certain clinical features of treatment of PsA and psoriasis, which was graded in categories I-IV. The literature searches were performed on the following classes of biologic agents and small molecules: TNF inhibitors (adalimumab, etanercept, infliximab, golimumab, certolizumab), anti-IL12/IL23 (ustekinumab), anti-IL17 (secukinumab, brodalumab, ixekizumab), anti-IL6 (tocilizumab), T cell modulators (alefacept, efalizumab, abatacept, itolizumab), B cell depletion therapy (rituximab), phosphodiesterase 4 inhibitor (apremilast) and Janus kinase inhibitor (tofacitinib). A comprehensive table including 17 different biologic agents and small molecule inhibitors previously tested in psoriasis and PsA was generated, including the level of evidence of their efficacy for each of the clinical features included in our review (axial and peripheral arthritis, enthesitis, dactylitis, and nail and skin disease). We also proposed a limited set of recommendations for a sequential biologic treatment algorithm for patients with PsA who failed the first anti-TNF therapy, based on the available literature data. There is good evidence that many of the biologic treatments initially tested in psoriasis are also effective in PsA. Further research into both prognostic biomarkers and patient stratification is required to allow clinicians the possibility to make better use of the various biologic treatment options available. This review showed that there are many potentially new treatments that are not included in the current guidelines that can be used for selected categories of patients based on their disease phenotype, clinician experience and access to new biologic therapies.

Familial Exudative Vitreoretinopathy: Spectral-Domain Optical Coherence Tomography of the Vitreoretinal Interface, Retina, and Choroid.

PURPOSE: The in vivo microstructural features of familial exudative vitreoretinopathy (FEVR) have not been well described. We present new anatomic features of FEVR with functional and genetic correlations. DESIGN: Consecutive, retrospective, observational case series. PARTICIPANTS: Patients with FEVR treated from 2009 to 2014. METHODS: We identified 346 patients with FEVR. Those imaged with spectral-domain optical coherence tomography (SD OCT) with or without enhanced depth imaging (EDI) were included, and images were correlated with best-corrected visual acuity (BCVA), widefield angiography, fundus autofluorescence (AF), and wnt signaling pathway mutations. MAIN OUTCOME MEASURES: Exploratory SD OCT findings and BCVA. RESULTS: A total of 225 imaging sessions were acquired in 74 eyes from 41 patients. Mean age was 19.0 years. Sixty-seven eyes (91%) had interpretable images, of which 50 (75%) had anomalous microstructural findings; all eyes with FEVR severity of stage 2 or greater had abnormalities. A broad spectrum of features were identified: various forms of posterior hyaloidal organization, vitreomacular traction (VMT), vitreopapillary traction, vitreo-fold traction, vitreo-laser scar adhesion, diminished foveal contour, persistent fetal foveal architecture, cystoid macular edema (CME), intraretinal exudates and subretinal lipid aggregation, dry or edematous radial folds, and disruption of the ellipsoid zone. Mean foveal, central macular, and choroidal thicknesses were 305±145 µm, 337±160 µm, and 216±64 µm, respectively. In stages 1 to 2, greater foveal and central macular thicknesses (Rho=0.493, 0.544, respectively; both P<0.001) correlated with poorer BCVA, but not choroidal thickness (Rho=0.032; P=0.868). Posterior hyaloidal organization (P<0.001), VMT (P<0.001), CME (P<0.001), exudation (P<0.001), and disruption of the ellipsoid zone (P<0.001) were associated with poorer BCVA. Disruption of the ellipsoid zone (ß=0.699; P<0.001) and posterior hyaloidal organization (ß=0.289; P=0.011) retained significance in multivariate modeling (R2=0.627; P<0.001). Spectral-domain OCT detected all cases of angiographic edema and areas of outer retinal dysfunction that were hypoautofluorescent on AF. Microstructural-genetic associations were not identified. CONCLUSIONS: Spectral-domain OCT imaging identified microstructural anomalies in the majority of patients with FEVR.

General Medical Considerations for the Wilderness Adventurer: Medical Conditions That May Worsen With or Present Challenges to Coping With Wilderness Exposure.

Participation in wilderness and adventure sports is on the rise, and as such, practitioners will see more athletes seeking clearance to participate in these events. The purpose of this article is to describe specific medical conditions that may worsen or present challenges to the athlete in a wilderness environment.

General Medical Considerations for the Wilderness Adventurer: Medical Conditions That May Worsen With or Present Challenges to Coping With Wilderness Exposure.

Participation in wilderness and adventure sports is on the rise, and as such, practitioners will see more athletes seeking clearance to participate in these events. The purpose of this article is to describe specific medical conditions that may worsen or present challenges to the athlete in a wilderness environment.

Deletion of Hsd11b1 suppresses caloric restriction-induced bone marrow adiposity in male but not female mice.

Bone marrow adipose tissue (BMAT) comprises >10% of total adipose mass in healthy humans. It increases in diverse conditions, including ageing, obesity, osteoporosis, glucocorticoid therapy, and notably, during caloric restriction (CR). BMAT potentially influences skeletal, metabolic, and immune functions, but the mechanisms of BMAT expansion remain poorly understood. Our hypothesis is that, during CR, excessive glucocorticoid activity drives BMAT expansion. The enzyme 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) amplifies glucocorticoid activity by catalysing intracellular regeneration of active glucocorticoids from inert 11-keto forms. Mice lacking 11ß-HSD1 resist metabolic dysregulation and bone loss during exogenous glucocorticoid excess; thus, we hypothesised that 11ß-HSD1 knockout mice would also resist excessive glucocorticoid action during CR, thereby restrining BMAT expansion and bone loss. To test this, we first confirmed that 11ß-HSD1 is expressed in mouse and human bone marrow. We then investigated the effects of CR in male and female control and 11ß-HSD1 knockout mice from 9 to 15 weeks of age. CR increased Hsd11b1 mRNA in adipose tissue and bone marrow. Deletion of Hsd11b1 did not alter bone or BMAT characteristics in mice fed a control diet and had little effect on tibial bone microarchitecture during CR. Notably, Hsd11b1 deletion attenuated the CR-induced increases in BMAT and prevented increases in bone marrow corticosterone in males but not females. This was not associated with suppression of glucocorticoid target genes in bone marrow. Instead, knockout males had increased progesterone in plasma and bone marrow. Together, our findings show that knockout of 11ß-HSD1 prevents CR-induced BMAT expansion in a sex-specific manner and highlights progesterone as a potential new regulator of bone marrow adiposity.

The effects of caloric restriction on adipose tissue and metabolic health are sex- and age-dependent.

Caloric restriction (CR) reduces the risk of age-related diseases in numerous species, including humans. CR's metabolic effects, including decreased adiposity and improved insulin sensitivity, are important for its broader health benefits; however, the extent and basis of sex differences in CR's health benefits are unknown. We found that 30% CR in young (3-month-old) male mice decreased fat mass and improved glucose tolerance and insulin sensitivity, whereas these effects were blunted or absent in young females. Females' resistance to fat loss was associated with decreased lipolysis, energy expenditure and fatty acid oxidation, and increased postprandial lipogenesis, compared to males. The sex differences in glucose homeostasis were not associated with differential glucose uptake but with altered hepatic ceramide content and substrate metabolism: compared to CR males, CR females had lower TCA cycle activity and higher blood ketone concentrations, a marker of hepatic acetyl-CoA content. This suggests that males use hepatic acetyl-CoA for the TCA cycle whereas in females it accumulates, stimulating gluconeogenesis and limiting hypoglycaemia during CR. In aged mice (18-months old), when females are anoestrus, CR decreased fat mass and improved glucose homeostasis similarly in both sexes. Finally, in a cohort of overweight and obese humans, CR-induced fat loss was also sex- and age-dependent: younger females (<45 years) resisted fat loss compared to younger males while in older subjects (>45 years) this sex difference was absent. Collectively, these studies identify age-dependent sex differences in the metabolic effects of CR and highlight adipose tissue, the liver and oestrogen as key determinants of CR's metabolic benefits. These findings have important implications for understanding the interplay between diet and health, and for maximising the benefits of CR in humans.