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BACKGROUND: Despite their frequent concurrent use, little is known about the concomitant use of calcium channel blockers (CCBs) and selective serotonin reuptake inhibitors (SSRIs) on fracture risk. We compared risk of fractures in patients concomitantly treated with CCBs and SSRIs versus CCB-only users. We compared risk of fractures among concomitant CCB-SSRI users initiating cytochrome P450 3A4 (CYP3A4)-inhibiting SSRIs versus non-CYP3A4 inhibiting SSRIs. METHODS: This retrospective cohort study used IBM MarketScan commercial claims and Medicare Supplemental database (2007-2019). We included adults diagnosed with hypertension and depression, newly initiating SSRIs while being treated with CCBs (ie, concomitant CCB-SSRI users) and those who did not (ie, CCB-only users). Primary outcome was the first occurrence of any fracture. We used stabilized inverse probability of treatment weighting (sIPTW) based on propensity scores to balance baseline risk between groups. Cox proportional hazard regression modeling was used to compare fracture risk. RESULTS: We identified 191 352 concomitant CCB-SSRI and 956 760 CCB-only users (mean age = 56 years, 50.1% males). After sIPTW, compared with CCB-only users, CCBs-SSRIs users had a higher risk of fractures (hazard ratio [HR]: 1.43, 95% confidence interval [CI]: 1.22-1.66). No difference in the risk of fractures between concomitant users of CCB-CYP3A4-inhibiting SSRIs and those of CCB-non-CYP3A4 inhibiting SSRIs (HR: 1.10, 95% CI: 0.87-1.40) was observed. CONCLUSION AND RELEVANCE: Short-term concomitant CCB-SSRI use was associated with increased fracture risk. Concomitant CCBs and CYP3A4-inhibiting SSRIs compared with CCBs and non-CYP3A4 inhibiting SSRIs use was not associated with increased risk.
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STUDY OBJECTIVE: Clinicians may prescribe new medications (marker drug) to treat statin-related (index drug) adverse events, constituting a prescribing cascade. We aimed to identify modifiable statin characteristics (intensity and individual statin agents) associated with lower risk of prescribing cascades to inform clinical decisions in the presence of statin-related adverse events. DESIGN: A secondary analysis based on our previous work, a high-throughput sequence symmetry analysis screening for potential statin-related prescribing cascades. DATA SOURCE: MarketScan Commercial and Medicare Supplemental Insurance claims databases between 2005 and 2019. PATIENTS: Adults who initiated a statin between 2007 and 2018, and who were continuously enrolled in the same healthcare plan for at least 720 days before and 360 days after statin initiation. INTERVENTION: Among the previously identified 57 potential prescribing cascades, 42 statin-marker class dyad with a sample size of ≥ 500 were assessed in this study. MEASUREMENTS: We measured patients' baseline characteristics within -360 days of statin initiation and reported by modifiable statin characteristics. We also performed logistic regression and reported the adjusted odds ratios (aOR) with 95% confidence intervals (CI) of modifiable statin characteristics after adjusting for baseline characteristics. MAIN RESULTS: We identified 1,307,867 statin initiators who met the study criteria (21% elderly, 52% female). Compared with patients initiating low-intensity statins, those initiating moderate- or high-intensity statins had significantly greater odds to develop 29 (69%) prescribing cascades, including antidiabetic drugs such as dipeptidyl peptidase 4 (DPP-4) inhibitors (aOR 1.22; 95% CI, 1.11-1.35) and glucagon-like peptide-1 (GLP-1) analogs (aOR 1.31; 95% CI, 1.16-1.47), and opioids (aOR 1.18; 95% CI, 1.13-1.23). Individual statin agent selection also had a differential effect on 34 (81%) of the prescribing cascades. For example, compared with simvastatin initiators, the probability of initiating osmotically acting laxatives was significantly higher for lovastatin initiators (aOR 1.09; 95% CI, 1.03-1.15) and significantly lower in atorvastatin initiators (aOR 0.92; 95% CI, 0.89-0.94). CONCLUSION: Compared with low-intensity statins, high-intensity statins are associated with increased risk in many potential prescribing cascades, while the choice of individual statin agents affects the risk of prescribing cascades bidirectionally.
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Inibidores da Dipeptidil Peptidase IV , Inibidores de Hidroximetilglutaril-CoA Redutases , Adulto , Humanos , Feminino , Idoso , Estados Unidos , Masculino , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Medicare , Atorvastatina , Sinvastatina/uso terapêutico , Lovastatina , Estudos RetrospectivosRESUMO
PURPOSE: Statins are among the most prevalent medications prescribed and associated with adverse events that may prompt additional treatment (i.e., a prescribing cascade). No comprehensive assessment of statin-related prescribing cascades has been performed to our knowledge. METHODS: We utilized sequence symmetry analysis to iteratively screen prescribing sequences of all therapeutic classes ("marker" classes) based on Level 4 Anatomical Therapeutic Chemical codes among adult statin initiators, using IBM Marketscan commercial and Medicare supplemental claims databases (2005-2019). Order of initiation and secular trend-adjusted sequence ratios were calculated for each statin-marker class dyad, among marker class initiators ±90 days of statin initiation. Among signals classified as prescribing cascades, we calculated naturalistic number needed to harm (NNTH) within 1 year as the inverse of the excess risk among exposed. RESULTS: We identified 2 265 519 statin initiators (mean ± SD age, 56.4 ± 12.0 years; 48.7% women; 7.5% with cardiovascular disease). Simvastatin (34.4% of statin initiators) and atorvastatin (33.9%) were the most commonly initiated statins. We identified 160 significant statin-marker class dyad signals, of which 35.6% (n = 57) were classified as potential prescribing cascades. Of the top 25 strongest signals (lowest NNTH), 12 were classified as potential prescribing cascades, including osmotically acting laxatives (NNTH, 44, 95% CI 43-46), opioids + non-opioid combination analgesics (81, 95% CI 74-91), and first-generation cephalosporins (204, 95% CI 175-246). CONCLUSIONS: Using high-throughput sequence symmetry analysis screening, we identified previously known prescribing cascades as well as potentially new prescribing cascades based on known and unknown statin-related adverse events.
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Inibidores de Hidroximetilglutaril-CoA Redutases , Idoso , Adulto , Humanos , Feminino , Estados Unidos , Pessoa de Meia-Idade , Masculino , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Ensaios de Triagem em Larga Escala , Medicare , Sinvastatina/efeitos adversos , AtorvastatinaRESUMO
BACKGROUND: The use of a new medication (e.g., potassium supplementation) for managing a drug-induced adverse event (e.g., loop diuretic-induced hypokalemia) constitutes a prescribing cascade. However, loop diuretics are often stopped while potassium may be unnecessarily continued (i.e., relic). We aimed to quantify the occurrence of relics using older adults previously experiencing a loop diuretic-potassium prescribing cascade as an example. METHODS: We conducted a prescription sequence symmetry analysis using the population-based Medicare Fee-For-Service data (2011-2018) and partitioned the 150 days following potassium initiation by day to assess the daily treatment scenarios (i.e., loop diuretics alone, potassium alone, combination of loop diuretics and potassium, or neither). We calculated the proportion of patients developing the relic, proportion of person-days under potassium alone, the daily probability of the relic, and the proportion of patients filling potassium after loop diuretic discontinuation. We also identified the risk factors of the relic. RESULTS: We identified 284,369 loop diuretic initiators who were 8 times more likely to receive potassium supplementation simultaneously or after (i.e., the prescribing cascade), rather than before, loop diuretic initiation (aSR 8.0, 95% CI 7.9-8.2). Among the 66,451 loop diuretic initiators who subsequently (≤30 days) initiated potassium, 20,445 (30.8%) patients remained on potassium after loop diuretic discontinuation, and 9365 (14.1%) patients subsequently filled another potassium supplementation. Following loop diuretic initiation, 4.0% of person-days were for potassium alone, and daily probability of the relic was the highest after day 90 of loop diuretic initiation (5.6%). Older age, female sex, higher diuretic daily dose, and greater baseline comorbidities were risk factors for the relic, while patients having the same prescriber or pharmacy involved in the use of both medications were less likely to experience the relic. CONCLUSIONS: Our findings suggest the need for clinicians to be aware of the potential of relic to avoid unnecessary drug use.
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Potássio , Inibidores de Simportadores de Cloreto de Sódio e Potássio , Humanos , Feminino , Idoso , Estados Unidos , Inibidores de Simportadores de Cloreto de Sódio e Potássio/efeitos adversos , Medicare , Diuréticos/efeitos adversos , Suplementos NutricionaisRESUMO
Study objective: Half of patients with heart failure have preserved ejection fraction (HFpEF). Over the years, guidelines have recommended or advised against various therapies for HFpEF management. However, there is limited evidence on the trends in utilization of the various medications. The aim of this study was to examine the trends in the use of pharmacotherapies among patients with HFpEF from 2008 through 2020. Design: Retrospective cohort study of patients with HFpEF used MarketScan® Commercial and Medicare Supplemental Databases (2007-2020). Participants: Patients with HFpEF. Outcome measures: Utilization rates for angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), angiotensin receptor-neprilysin inhibitors (ARNIs), aldosterone receptor antagonists (ARAs), diuretics, ß-blockers, calcium channel blockers (CCBs), phosphodiesterase 5 inhibitors (PDE5Is), nitrates, digoxin, and sodium glucose cotransporter-2 inhibitors (SGLT2i) within 90 days of the first HFpEF diagnosis. Results: We identified 156,730 patients with HFpEF (mean [SD] age, 73 [13.4] years; 57 % females). From 2008 to 2020, we found increased utilization rates for ARNIs (0.02 % vs. 0.17 % of all patients, p < 0.01), ARBs (14.3 % vs. 18.6 %, p < 0.01), ARAs (7.0 % vs. 8.4 %, p < 0.01), CCBs (30.6 % vs. 33.4 %, p < 0.01), and SGLT2i (0.001 % vs. 0.021 %, p < 0.01). By contrast, the utilization of ACEIs (30.4 % vs. 20.5 %, p < 0.01), digoxin (9.5 % vs. 2.4 %, p < 0.01), nitrates (10.7 % vs. 4.9 %, p < 0.01), diuretics (54.1 % vs. 50.4 %, p = 0.20), and ß-blockers (52.6 % vs. 51.7 %, p < 0.01) decreased, while utilization rates of PDE5Is remained stable (1.5 % vs. 1.1 %, p = 0.90) . Conclusions: During the 13-year study period, the utilization of ARNIs, ARBs, ARAs, CCBs, and SGLT2i increased while the utilization of digoxin, nitrates, diuretics, and ß-blockers decreased among patients with HFpEF.
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BACKGROUND: Limited evidence exists regarding long-term effectiveness and safety of aldosterone antagonists (AAs) versus beta blockers (BBs) as fourth-line antihypertensive agents in patients with resistant hypertension (RH). We evaluated the comparative effectiveness and safety of aldosterone AA versus BB. METHODS: We conducted a real-world retrospective cohort study using IBM MarketScan commercial claims and Medicare Supplemental claims (2007-2019). Patients with RH entered the cohort (ie, index date) when they newly initiated either AA or BB. The effectiveness outcome was major adverse cardiovascular events. Safety outcomes were hyperkalemia, gynecomastia, and kidney function deterioration. Potential confounding was addressed by adjustment for baseline characteristics via stabilized inverse probability of treatment weighting (SIPTW) based on propensity scores. Cox proportional hazards regression with SIPTWs were used to estimate adjusted hazard ratio (aHR) and 95% CI comparing risk for outcomes between AA and BB groups. RESULTS: We identified 80 598 patients with RH (mean age: 61 years, 51% males), of which 6626 initiated AA and 73 972 initiated BB as the fourth antihypertensive agent. Among patients with RH, initiation of AA as a fourth-line antihypertensive agent did not significantly reduce major adverse cardiovascular event risk relative to BB initiation (aHR, 0.77 [95% CI, 0.50-1.19]) but did substantially increase the risk of hyperkalemia (aHR, 3.86 [95% CI, 2.78-5.34]), gynecomastia (aHR, 9.51 [95% CI, 5.69-15.89]), and kidney function deterioration (aHR, 1.63 [95% CI, 1.34-1.99]). CONCLUSIONS: Long-term clinical trials powered to assess major adverse cardiovascular events are necessary to understand the risk-benefit trade-off of AA as fourth-line therapy for RH.
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Ginecomastia , Hiperpotassemia , Hipertensão , Antagonistas Adrenérgicos beta/efeitos adversos , Idoso , Anti-Hipertensivos/efeitos adversos , Feminino , Ginecomastia/induzido quimicamente , Ginecomastia/tratamento farmacológico , Humanos , Hiperpotassemia/induzido quimicamente , Hiperpotassemia/epidemiologia , Hipertensão/induzido quimicamente , Hipertensão/tratamento farmacológico , Masculino , Medicare , Pessoa de Meia-Idade , Antagonistas de Receptores de Mineralocorticoides/efeitos adversos , Estudos Retrospectivos , Estados Unidos/epidemiologiaRESUMO
PURPOSE: There is limited evidence to support the use of direct-acting oral anticoagulants (DOACs) in patients with venous thromboembolism (VTE) and active cancer. This study aimed to assess the effectiveness of DOACs versus warfarin for the prevention of recurrent VTE and major bleeding events in patients with VTE and active cancer. METHODS: We identified patients with incident VTE and active cancer who newly initiated treatment with DOACs or warfarin from Truven Health MarketScan Commercial Claims and Medicare supplemental databases. Patients were followed up from treatment initiation (index date) until the occurrence of >7-day gap in treatment, the start of the study comparator, an outcome of interest (recurrent VTE or major bleeding), inpatient death, disenrollment, or end of the study period, whichever occurred first. We controlled for confounders via propensity score matching and estimated the hazard ratios (HRs) using Cox proportional hazards regression models. FINDINGS: A total of 9952 patients were included in the matched cohort (4976 DOACs users and 4976 warfarin users). Patient characteristics were well balanced after matching. We observed a lower incidence of recurrent VTE (3 vs 5 per 100 person-years) and major bleeding events (2 vs 3 per 100 person-years) in the DOAC group compared to warfarin group, respectively. In Cox regression models, use of DOACs (vs warfarin) was associated with a lower risk of recurrent VTE (hazard ratio (HR), 0.59; 95% CI, 0.42-0.82) and major bleeding events (HR, 0.64; 95% CI, 0.44-0.94). IMPLICATIONS: On the basis of our findings, among patients with VTE and active cancer, DOACs offer superior effectiveness with a lower risk of bleeding when compared with warfarin for the secondary prevention of VTE.
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Anticoagulantes/uso terapêutico , Inibidores do Fator Xa/uso terapêutico , Tromboembolia Venosa/tratamento farmacológico , Varfarina/uso terapêutico , Administração Oral , Idoso , Estudos de Coortes , Bases de Dados Factuais , Feminino , Hemorragia/induzido quimicamente , Humanos , Incidência , Masculino , Medicare , Pessoa de Meia-Idade , Neoplasias/patologia , Estudos Retrospectivos , Prevenção Secundária , Estados UnidosRESUMO
PURPOSE: Compared with conventional therapy (enoxaparin followed by warfarin), the direct-acting oral anticoagulant apixaban is thought to offer similar protection against recurrent venous thromboembolism (VTE) with lower bleeding risk. However, evidence regarding the heterogeneity of treatment effect from real-world data is lacking. The study described here aimed to compare the effectiveness and safety of use of apixaban versus warfarin in patients with VTE. METHODS: We conducted a retrospective cohort analysis of commercial and Medicare supplemental databases (data coverage period, 2014-2017) among patients with a diagnosis of VTE who were new users of apixaban or warfarin. We controlled for confounding using propensity score [PS] 1:4 matching. Cox proportional hazard models were used to obtain hazard ratios (HRs) and 95% confidence intervals (CIs). Heterogeneity of treatment effect was assessed among patients with provoked VTE versus unprovoked VTE. RESULTS: After PS matching, a total of 36,907 patients were included in the cohort (n = 8,094 apixaban users and n = 28,813 warfarin users). In Cox regression models, the use of apixaban versus warfarin was associated with lower risks of recurrent VTE (HR, 0.54; 95% CI, 0.45-0.65) and major bleeding events (HR, 0.67; 95% CI, 0.54-0.84); these results remained consistent in patients with provoked VTE and those with unprovoked VTE. CONCLUSION: This population-based analysis of patients with VTE extends results of randomized clinical trials indicating lower risks of development of recurrent VTE and major bleeding events with use of apixaban versus warfarin in real-world settings. The observed benefits of apixaban extended to selected subgroups of the VTE population, including patients with provoked VTE.
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Anticoagulantes/administração & dosagem , Pirazóis/administração & dosagem , Piridonas/administração & dosagem , Tromboembolia Venosa/tratamento farmacológico , Varfarina/administração & dosagem , Adulto , Idoso , Anticoagulantes/efeitos adversos , Estudos de Coortes , Feminino , Seguimentos , Hemorragia/induzido quimicamente , Hemorragia/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Pirazóis/efeitos adversos , Piridonas/efeitos adversos , Estudos Retrospectivos , Varfarina/efeitos adversosRESUMO
Resistant hypertension (RH) is defined as above-goal elevated blood pressure (BP) in a patient despite the concurrent use of 3 antihypertensive drug classes, commonly including a long-acting calcium channel blocker, a blocker of the renin-angiotensin system (angiotensin-converting enzyme inhibitor or angiotensin receptor blocker), and a diuretic. The antihypertensive drugs should be administered at maximum or maximally tolerated daily doses. RH also includes patients whose BP achieves target values on ≥4 antihypertensive medications. The diagnosis of RH requires assurance of antihypertensive medication adherence and exclusion of the "white-coat effect" (office BP above goal but out-of-office BP at or below target). The importance of RH is underscored by the associated risk of adverse outcomes compared with non-RH. This article is an updated American Heart Association scientific statement on the detection, evaluation, and management of RH. Once antihypertensive medication adherence is confirmed and out-of-office BP recordings exclude a white-coat effect, evaluation includes identification of contributing lifestyle issues, detection of drugs interfering with antihypertensive medication effectiveness, screening for secondary hypertension, and assessment of target organ damage. Management of RH includes maximization of lifestyle interventions, use of long-acting thiazide-like diuretics (chlorthalidone or indapamide), addition of a mineralocorticoid receptor antagonist (spironolactone or eplerenone), and, if BP remains elevated, stepwise addition of antihypertensive drugs with complementary mechanisms of action to lower BP. If BP remains uncontrolled, referral to a hypertension specialist is advised.
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Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/fisiologia , Hipertensão/diagnóstico , American Heart Association , Gerenciamento Clínico , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/terapia , Estados UnidosRESUMO
Karrikins and strigolactones are novel plant growth regulators that contain similar molecular features, but very little is known about how they elicit responses in plants. A tentative molecular mechanism has previously been proposed involving a Michael-type addition for both compounds. Through structure-activity studies with karrikins, we now propose an alternative mechanism for karrikin and strigolactone mode of action that involves hydrolysis of the butenolide ring.
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Furanos/farmacologia , Lactonas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Piranos/farmacologia , Sítios de Ligação , Simulação por Computador , Furanos/química , Germinação/efeitos dos fármacos , Lactonas/química , Reguladores de Crescimento de Plantas/química , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Estrutura Terciária de Proteína , Piranos/química , Sementes/metabolismo , Solanum/crescimento & desenvolvimento , Solanum/metabolismo , Relação Estrutura-AtividadeRESUMO
Karrikinolide is a naturally derived potent seed germination stimulant that is responsible for triggering the germination of numerous plant species from various habitats around the world. We now report that solar irradiation of karrikinolide yields two novel head-to-head cage photodimers with the formation, stability and bioactivity of both presented herein.
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Furanos/química , Piranos/química , Solanum/efeitos dos fármacos , Dimerização , Furanos/farmacologia , Germinação/efeitos dos fármacos , Modelos Moleculares , Estrutura Molecular , Processos Fotoquímicos , Piranos/farmacologia , Sementes/efeitos dos fármacos , Solanum/crescimento & desenvolvimentoRESUMO
Karrikins (2H-furo[2,3-c]pyran-2-ones) are potent smoke-derived germination promoters for a diverse range of plant species but, to date, their mode of action remains unknown. This paper reports the structure-activity relationship of numerous karrikin analogues to increase understanding of the key structural features of the molecule that are required for biological activity. The results demonstrate that modification at the C5 position is preferred over modification at the C3, C4, or C7 positions for retaining the highest bioactivity.
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Furanos/química , Furanos/farmacologia , Germinação/efeitos dos fármacos , Piranos/química , Piranos/farmacologia , Solanum/fisiologia , Estrutura Molecular , Sementes/efeitos dos fármacos , Sementes/fisiologia , Solanum/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Glucan phosphorylating enzymes are required for normal mobilization of starch in leaves of Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum), but mechanisms underlying this dependency are unknown. Using two different activity assays, we aimed to identify starch degrading enzymes from Arabidopsis, whose activity is affected by glucan phosphorylation. Breakdown of granular starch by a protein fraction purified from leaf extracts increased approximately 2-fold if the granules were simultaneously phosphorylated by recombinant potato glucan, water dikinase (GWD). Using matrix-assisted laser-desorption ionization mass spectrometry several putative starch-related enzymes were identified in this fraction, among them beta-AMYLASE1 (BAM1; At3g23920) and ISOAMYLASE3 (ISA3; At4g09020). Experiments using purified recombinant enzymes showed that BAM1 activity with granules similarly increased under conditions of simultaneous starch phosphorylation. Purified recombinant potato ISA3 (StISA3) did not attack the granular starch significantly with or without glucan phosphorylation. However, starch breakdown by a mixture of BAM1 and StISA3 was 2 times higher than that by BAM1 alone and was further enhanced in the presence of GWD and ATP. Similar to BAM1, maltose release from granular starch by purified recombinant BAM3 (At4g17090), another plastid-localized beta-amylase isoform, increased 2- to 3-fold if the granules were simultaneously phosphorylated by GWD. BAM activity in turn strongly stimulated the GWD-catalyzed phosphorylation. The interdependence between the activities of GWD and BAMs offers an explanation for the severe starch excess phenotype of GWD-deficient mutants.
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Arabidopsis/enzimologia , Fosfotransferases (Aceptores Pareados)/metabolismo , Solanum tuberosum/enzimologia , Amido/metabolismo , beta-Amilase/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/isolamento & purificação , Fosforilação , Extratos Vegetais/metabolismo , Folhas de Planta/enzimologia , Plastídeos/enzimologia , Proteínas Recombinantes/metabolismo , Solanum tuberosum/metabolismoRESUMO
The aim of this research was to test the role of the glyoxylate cycle enzyme malate synthase (MLS) in lipid utilization, gluconeogenesis, and seedling growth in Arabidopsis. We hypothesized that in the absence of MLS, succinate produced by isocitrate lyase (ICL) could still feed into the tricarboxylic acid cycle, whereas glyoxylate could be converted to sugars using enzymes of the photorespiratory pathway. To test this hypothesis we isolated knock-out mls mutants and studied their growth and metabolism in comparison to wild type and icl mutant seedlings. In contrast to icl seedlings, which grow slowly and are unable to convert lipid into sugars (Eastmond, P. J., Germain, V., Lange, P. R., Bryce, J. H., Smith, S. M. & Graham, I. A. (2000) Proc. Natl. Acad. Sci. U. S. A. 97, 5669-5674), mls seedlings grow faster, use their lipid more rapidly, and are better able to establish as plantlets. Transcriptome and metabolome analyses show that icl seedlings exhibit many features characteristic of carbohydrate starvation, whereas mls seedlings differ relatively little from wild type. In the light mls seedlings generate more sugars than icl seedlings, and when fed with [14C]acetate, 14C-labeling of sugars is three times greater than in icl seedlings and more than half that in wild type seedlings. The mls seedlings also accumulate more glycine and serine than icl or wild type seedlings, consistent with a diversion of glyoxylate into these intermediates of the photorespiratory pathway. We conclude that, in contrast to bacteria and fungi in which MLS is essential for gluconeogenesis from acetate or fatty acids, MLS is partially dispensable for lipid utilization and gluconeogenesis in Arabidopsis seedlings.