Posterior surgical approach for the treatment of lower cervical spine injury with spinal cord paralysis: high postoperative mortality in resource-scare setting.

OBJECTIVE: This report aimed to characterize clinical and imaging characteristics and outcomes of the patients with lower cervical spine injury combined with spinal cord paralysis who underwent posterior cervical spine surgery. PATIENTS AND METHODS: Between January 2019 and December 2020, a retrospective evaluation of prospectively collected data at one institution was conducted. We included all patients who were diagnosed with subaxial cervical spine injuries (C3-7), had spinal cord paralysis, and underwent posterior cervical spine surgery. Clinical profile, preoperative characteristics, intraoperative data, and postoperative outcomes were retrieved from prospective patients' medical records and computerized database. RESULTS: Among 70 selected patients, most were male (66, 94.29%) and the average age was 48.41 ± 14.33 years. Most of them worked in agriculture (90.4%). Clinical symptoms included neck pain (58, 82.86%), cervical radiculopathy (50, 71.43%), loss of sensation (44, 62.86%), and decreased sensation (21, 30.00%). The most frequent cervical spinal injuries involved C5 (28.57%), followed by C7 (14.29%). Circular muscle dysfunction was present in 65 (92.86%) patients. Early complications included respiratory failure (12.85%), pneumonia (11.42%), bedsores (8.57%), and urinary tract infection (7.14%). Common late complications included movement disorder (48.21%), muscle weakness and stiffness (37.50%), sensory disturbances (32.14%), urinary tract infection (17.86%), bedsores (16.07%), and pneumonia (5.36%). Patients after surgery and at follow-up had a significant improvement compared to preoperative assessment according to the AIS classification, and recovery of smooth muscle. Three patients died within 1 month following surgery, 3 within 1-3 month(s), 2 within 3-6 months, and 1 case beyond 6 months. CONCLUSIONS: In hospital-based clinical condition with limited practice approach, our study indicated specific clinical and imaging characteristics of Vietnamese patients with lower cervical spine injury combined with spinal cord paralysis. With high postoperative mortality rate, commonly late complications after posterior cervical spine surgical approach were pain and difficulty in neck movement, muscle weakness and stiffness, and nerve root pain.

Characterizations and Fibrinolytic Activity of Serine Protease from Bacillus subtilis C10.

BACKGROUND: Fibrinolytic enzymes, such as Nattokinases from Bacillus species are known to degrade the fibrin blood clots. They belong to serine protease group having commercial applications, such as therapeutic agents and functional food formulation. OBJECTIVE: The present study reports some characteristics and fibrinolytic activity of serine protease from B. subtilis C10 strain that was isolated from shrimp shell. METHODS: Extracellular enzyme from B. subtilis C10 culture was harvested and partially purified by ammonium sulphate precipitation. Fibrinolytic activity of the enzyme was determined by zymography and measured by spectrophotometry with fibrinogen and thrombin used as substrates. The optimal temperature and pH for fibrinolytic activity were studied in the range of 31-43ºC and 5-10, respectively. The thermal and pH stability of enzyme was studied by incubating enzyme for 30 min in the same range of temperature and pH as above. The effect of some metal ions and reagents on fibrinolytic activity of enzyme was evaluated by concentrations of 5 mM and 5%, respectively. RESULTS: Zymogram analysis indicated the presence of four fibrinolytic enzymes with molecular weights of approximately 69, 67, 39 and 36 kDa. The optimal temperature and pH for enzyme activity were 37°C and 9, respectively. The thermal and pH stability ranged from 35-39°C and 8-10, respectively. Fibrinolytic activity reached a maximum value of about 400 U/mg protein after 16 h of C10 strain culture. Enzyme has been drastically inhibited by PMSF and SDS, and partially inhibited by EDTA, while Triton X-100 has significantly increased enzyme activity. Effects of ions such as Mg2+, Ca2+ and Mn2+ on enzyme were negligible, except Cu2+ and Zn2+ have strongly decreased its activity. CONCLUSION: Results from the present study suggested that enzyme obtained from B. subtilis C10 could be serine protease that has a high fibrinolytic activity up to about 400 U/mg protein at the most appropriate temperature and pH of 37ºC and 9. This activity can be improved up to 142% by incubating enzyme with 5% Triton X-100 for 30 min.

Contrast Functions of αA- and αB-Crystallins in Cancer Development.

α-Crystallins, initially identified as the structural proteins of the ocular lens, belong to the small heat shock protein family. They play significant roles in maintaining the lens transparency and preventing protein aggregation. α-Crystallins exist in two isoforms: αA and αB, and they display differential tissue distribution. Their mutations are implicated in several human diseases including cardiac myopathies, neurodegenerative diseases, cataracts and various types of cancers. Increased αB expression was detected in retinoblastoma, breast cancer, glioblastoma, prostate and renal cell carcinomas, indicating its role in promoting tumor growth. A complex picture emerges for αA. Although earlier studies suggest that αA may promote cancer development, recent studies from our laboratory demonstrate that αA can act as a tumor suppressor inhibiting cell transformation and retarding cell migration through modulating MAP kinase activity. In this review, we summarize the recent progress about the functions of αA and αB in cancer development.

Regulation of CREB Functions by Phosphorylation and Sumoylation in Nervous and Visual Systems.

CREB is an ubiquitous transcription factor regulating diverse cellular responses. Its phosphorylation at S133 is an essential event for its activation in both nervous and visual systems. The activated CREB is implicated in the regulation of development, protection, learning, memory and plasticity in the nerve system. Moreover, sumoylation, an important post-translational modification of protein, plays a key role in sustaining CREB activation in the rat hippocampus in order to enhance the long-term memory and other aspects. In the visual system, although the CREB activation by phosphorylation at S133 is similar to that as observed in the nervous system, the role of CREB sumoylation remains to be explored. This review will discuss the aspects of CREB functions and their regulation by phosphorylation and sumoylation in both systems.

Month-6 primary outcomes of the READ-3 study (Ranibizumab for Edema of the mAcula in Diabetes-Protocol 3 with high dose).

PURPOSE: To compare 2.0 mg ranibizumab (RBZ) injections with 0.5 mg RBZ for eyes with center-involved diabetic macular edema (DME) and a central subfield thickness (CFT) of ≥250 µm on time-domain optical coherence tomography.DesignRandomized, controlled, multicenter clinical trial. METHODS: Eligible eyes were randomized in a 1:1 ratio to 0.5 mg (n=77) or 2.0 mg (n=75) RBZ. Study eyes received 6-monthly injections.Main outcome measuresThe primary outcome measure was the mean change in best corrected visual acuity (BCVA) at month 6. Secondary outcomes included the incidence and severity of systemic and ocular adverse events and the mean change in CFT from baseline. RESULTS: In all, 152 eyes (152 patients) were randomized in the study. At month 6, the mean improvement from baseline BCVA was +9.43 letters in the 0.5 mg RBZ group and +7.01 letters in the 2.0 mg RBZ group (P=0.161). At month 6, one death occurred in the 0.5 mg RBZ group and three deaths in the 2.0 mg RBZ group, all due to myocardial infarction in subjects with a prior history of heart disease. Mean CFT was reduced by 168.58 µm in the 0.5 mg RBZ group and by 159.70 µm in the 2.0 mg RBZ group (P=0.708). CONCLUSIONS: There was no statistically significant difference in the mean number of letters gained between the 0.5 and 2.0 mg RBZ groups through month 6. In this DME study population, high-dose RBZ does not appear to provide additional benefit over 0.5 mg RBZ.

Assessment of Retinal Structural and Functional Characteristics in Eyes with Autoimmune Retinopathy.

PURPOSE: To evaluate the thicknesses of individual retinal layers, and the correlation between structural changes and functional loss using spectral domain optical coherence tomography (SD-OCT) scans and electroretinograms (ERG), in eyes with autoimmune retinopathy (AIR). METHODS: SD-OCT raster scans of 12 eyes from 6 patients serologically diagnosed with AIR were evaluated. Retinal layers were segmented along a 5 mm horizontal scan passing through the fovea. Retinal layers analyzed include full retinal thickness (FRT), retinal pigment epithelium and Bruch's membrane complex (RPE+BM complex), photoreceptor layer (PRL), inner nuclear layer (INL), combined ganglion cell and inner plexiform layers (GCL+), nerve fiber layer (NFL), and combined GCL+ and NFL layers (GCL+/NFL). Changes in the thicknesses of the layers were assessed in 0.5 mm increments along the B-scan in the central, nasal, and temporal regions. These recorded values were compared to corresponding values of 51 eyes from 51 subjects with no known ocular pathology. Full-field ERGs were obtained at corresponding visits and were interpreted by a grader masked to the diagnoses and OCT findings. RESULTS: The mean age of the patients was 59.5 years (range, 33-83), with 4 males (66.6%). Within the control population of 51 subjects, mean age was 51.5 years (range, 40-75), with 25 males (49%). Eyes with AIR showed a loss of retinal tissue compared to eyes with no known ocular pathology at the fovea. Specifically, the FRT, RPE+BM complex, and PRL exhibited thinning of statistically significance. ERG findings demonstrated a functional deficit which showed a good correlation with structural loss. Fifty (50) percent of eyes experienced central photoreceptor (rod and cone) dysfunction and 75% of eyes displayed peripheral photoreceptor (rod and cone) dysfunction. CONCLUSIONS: Eyes with AIR show a loss of retinal tissue compared to eyes with no known ocular pathology. The greatest loss appears to occur in the RPE and PRL. ERG findings correlate strongly with the loss of tissue seen in these layers. Thus, therapeutic options may be targeted to preserve these regions of the retina.

Therapies in Development for Non-Infectious Uveitis.

Uveitis represents a spectrum of diseases characterized by ocular inflammation that leads to significant visual loss if left untreated. Adequate, long-term control of inflammation with minimal systemic and local adverse effects is the preferred strategy for treating patients with uveitis. Pharmacotherapy for uveitis consists mainly of corticosteroids in various formulations such as topical, local, intraocular and systemic. However, monotherapy with corticosteroids is often unacceptable due to serious adverse effects on various organ systems. There exist limitations with the use of steroid-sparing systemic immunosuppressive agents, as these medications may have significant adverse events and a narrow therapeutic window. Thus, newer molecular targets that act on various steps of the inflammatory pathway appear to be promising emerging strategies for treating uveitis. Specially designed monoclonal antibodies in development can potentially halt the inflammatory processes resulting in remission of the disease. In the index review, novel molecular agents and biological therapies that have shown promising efficacy and safety data in preclinical and clinical studies have been summarized. In addition, new drug delivery systems that may ensure high intraocular therapeutic levels of pharmacologic agents have been highlighted.

The Role of αA-Crystallin in Experimental Autoimmune Uveitis.

Uveitis refers to a group of ocular inflammatory diseases that can lead to blindness. For years, researchers have been trying to decipher the underlying mechanisms and develop therapeutic strategies using the model of experimental autoimmune uveitis (EAU). Recently, αA-crystallin has been found to be upregulated in EAU and can even ameliorate its severity through different mechanisms, suggesting its use as a potent therapeutic factor against uveitis. Here we review the protective role of αA-crystallin and discuss its functional mechanisms in EAU.

Design, synthesis and initial characterisation of a radiolabelled [(18)F]pyrimidoindolone probe for detecting activated caspase-3/7.

Evasion of apoptosis is one of the six initially proposed hallmarks of cancer, and as such, a method to detect apoptosis in a tumour would be of considerable interest in both clinical trials of new cancer therapeutics, as well as for routine patient management. Activation of caspase-3/7 is a key biomarker of cellular apoptosis. Herein we describe the design, synthesis and initial characterisation of the first pyrimidoindolone compound for detection of caspase-3/7 activation using positron emission tomography.

The tumor suppressor, p53 regulates the γA-crystallin gene during mouse lens development.

The tumor suppressor, p53 regulates a large number of target genes to control cell proliferation and apoptosis. In addition, it is also implicated in the regulation of cell differentiation in muscle, the circulatory system and various carcinoma tissues. We have recently shown that p53 also controls lens differentiation. Regarding the mechanism, we reveal that p53 directly regulates several genes including c-Maf and Prox1, two important transcription factors for lens differentiation, and αA and ßA3/A1, the lens differentiation markers. In the present study, we present evidence to show that the γA-crystallin gene distal promoter and the first intron also contain p53 binding sites and are capable of mediating p53 control during mouse lens development. First, gel mobility shifting assays revealed that the p53 protein in nuclear extracts from human lens epithelial cells (HLE) directly binds to the p53 binding sites present in the γA-crystallin gene. Second, the exogenous wild type p53 induces the dose-dependent expression of the luciferase reporter gene driven by the basic promoter containing the γA-crystallin gene p53 binding site. In contrast, the exogenous dominant negative mutant p53 causes a dose-dependent inhibition of the same promoter. Third, ChIP assays revealed that p53 binds to the γA-crystallin gene promoter in vivo. Finally, in the p53 knockout mouse lenses, the expression level of the γAcrystallin gene was found attenuated in comparison with that in the wild type mouse lenses. Together, our results reveal that p53 regulates γA-crystallin gene expression during mouse lens development. Thus, p53 directly regulates all 3 types of crystallin genes to control lens differentiation.

Association of retinal vessel calibre and visual outcome in eyes with diabetic macular oedema treated with ranibizumab.

PURPOSE: The study aims to identify the association between the baseline retinal vascular calibre and visual outcome of patients with diabetic macular oedema (DMO) treated with intravitreal ranibizumab. METHODS: The 1-M field (as defined in the ETDRS study) of the digital colour fundus photographs of DMO patients who had been treated primarily with ranibizumab in a clinical trial was assessed. Of the 84 patients, 25 had gradable retinal photographs that could be subjected to analyses by the Interactive Vessel Analysis (IVAN) software at baseline. The average retinal vascular calibre of the six largest venules (CRVE) and the six largest arterioles (CRAE) in the peripapillary area (0.5 and 1 disc diameter from the optic disc margin) was measured. The relationship between CRVE and CRAE at baseline and the change in visual acuity at month 12 was assessed using the Mann-Whitney U test. RESULTS: Ten eyes from 10 patients who had shown an improvement of ≥2 lines of best corrected visual acuity (BCVA) at month 12 had a wider baseline CRVE (248.3±24.5 µm) compared with the 15 eyes from 15 patients who did not show the improvement of ≥2 lines (226.6±44.8 µm, P<0.05). The baseline CRAE did not differ significantly in these patients (156.1±22.7 vs 142±17.5 µm, P=0.17). CONCLUSIONS: A wider baseline retinal venular calibre may be a predictor of better visual outcome in DMO eyes treated with ranibizumab. Further prospective studies with a larger sample size and a broader range of disease severity and visual acuity are needed to confirm this finding.

Longitudinal comparison of visual acuity as measured by the ETDRS chart and by the potential acuity meter in eyes with macular edema, and its relationship with retinal thickness and sensitivity.

PURPOSE: To evaluate the relationship between visual acuity as measured by the Early Treatment Diabetic Retinopathy Study (ETDRS) chart and by the potential acuity meter (PAM) with retinal thickness and sensitivity measured by a combined microperimetry/optical coherence tomography system (OCT). METHODS: Forty-four patients with macular edema (ME) were included in a prospective observational study. Visual acuity (VA) was assessed using the ETDRS chart (with best correction) as well as by the PAM. Retinal thickness and sensitivity was measured by an automatic fundus perimetry/tomography system. RESULTS: Best-corrected VA using the ETDRS chart ranged from 20/20 to 20/400 (median: 20/50). VA measured by the PAM without correction ranged from 20/20 to 20/400 (median: 20/40). The mean retinal thickness was 369.57 µm (s.d.: 140.28 µm) on spectral domain-OCT and the mean retinal sensitivity was 8.12 decibels (dB) (s.d.: 5.78 dB). The mean LogMAR value using the ETDRS chart was 0.43, whereas it was 0.38 using the PAM (P-value: 0.009). CONCLUSIONS: VA values measured by the PAM were statistically significantly better than those measured by the ETDRS chart in eyes with ME secondary to various retinal vascular and uveitic diseases. VA measured by the PAM may be a more sensitive predictor of macular function than that obtained by ETDRS testing in eyes with ME.

Factors affecting visual outcomes in patients with diabetic macular edema treated with ranibizumab.

PURPOSE: To identify factors associated with visual outcomes in patients with diabetic macular edema (DME) treated with ranibizumab (RBZ) in the Ranibizumab for Edema of the mAcula in Diabetes-Protocol 2 (READ-2) Study. PATIENTS AND METHODS: Optical coherence tomography scans, fundus photographs, and fluorescein angiograms (FAs) were graded and along with baseline characteristics were correlated with month (M) 24 visual outcome of best-corrected visual acuity (BCVA) ≤20/100 (poor outcome) vs >20/100 (better outcome). RESULTS: Of 101 patients with a M20 visit or beyond, 27 (27%) had BCVA ≤20/100. Comparison of patients with or without poor outcome showed mean baseline BCVA of 16.8 letters (20/125) in the former compared with 30.4 letters (20/63; P<0.001). Mean change in BCVA between baseline and M24 was -2.6 letters in the poor outcome group compared with +9.8 letters (P<0.001). Foveal thickness (FTH) at M24 was 374.1 µm in the poor outcome group compared with 268.8 µm (P<0.01), a difference driven by 14 patients with mean FTH of 450.3 µm. Foveal atrophy occurred in 65% (11/17) in the poor outcome group compared with 17%(12/71, P=0.001). Persistent edema was noted in 52% (14/27) of patients with poor outcome. Laser scars near foveal center were significantly more common in patients with poor outcome who did not have edema vs those who did (78% (7/9) vs 23% (3/13) P=0.03). CONCLUSION: Poor baseline BCVA (≤20/125) in DME patients predicts poor visual outcome (≤20/100) after 2 years of treatment with RBZ and/or focal/grid laser, often due to foveal atrophy and/or persistent edema.

Adverse events and complications associated with intravitreal injection of anti-VEGF agents: a review of literature.

Intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents is increasingly used for the treatment of a wide variety of retinal diseases, including age-related macular degeneration, diabetic retinopathy and retinal vascular occlusions, and retinopathy of prematurity. Despite encouraging results in halting the disease and improving the vision, intravitreal injection of anti-VEGF agents may be associated with systemic adverse events and devastating ocular complications. In this review, we provide an overview of safety data for intravitreal injection of common anti-VEGF agents.

A novel small molecule hydroxamate preferentially inhibits HDAC6 activity and tumour growth.

BACKGROUND: This study investigates whether a histone deacetylase subtype 6 (HDAC6) inhibitor could be used in the treatment of solid tumours. METHODS: We evaluated the effect of a novel inhibitor, C1A, on HDAC6 biochemical activity and cell growth. We further examined potential of early noninvasive imaging of cell proliferation by [(18)F]fluorothymidine positron emission tomography ([(18)F]FLT-PET) to detect therapy response. RESULTS: C1A induced sustained acetylation of HDAC6 substrates, α-tubulin and HSP90, compared with current clinically approved HDAC inhibitor SAHA. C1A induced apoptosis and inhibited proliferation of a panel of human tumour cell lines from different origins in the low micromolar range. Systemic administration of the drug inhibited the growth of colon tumours in vivo by 78%. The drug showed restricted activity on gene expression with <0.065% of genes modulated during 24 h of treatment. C1A treatment reduced tumour [(18)F]FLT uptake by 1.7-fold at 48 h, suggesting that molecular imaging could provide value in future studies of this compound. CONCLUSION: C1A preferentially inhibits HDAC6 and modulates HDAC6 downstream targets leading to growth inhibition of a diverse set of cancer cell lines. This property together with the favourable pharmacokinetics and efficacy in vivo makes it a candidate for further pre-clinical and clinical development.

Phase 1 dose-escalation study of a siRNA targeting the RTP801 gene in age-related macular degeneration patients.

BACKGROUND: To evaluate the safety, tolerability, pharmacokinetics, and dose-limiting toxicities of a single intravitreal (IVT) injection of PF-04523655, a 19-nucleotide, O-methyl stabilized, double-stranded small interfering ribonucleic acid targeting the RTP801 gene in patients with neovascular age-related macular degeneration (AMD). METHODS: Prospective, phase 1, clinical multicentre trial, enrolled 27 patients with neovascular AMD unresponsive to prior treatment and best corrected visual acuity (BCVA) ≤ 20/200 in the study eye in stratum 1: (dose-escalating, open-label: 50 to 3000 µg of PF-04523655) and 27 patients who had potential to benefit from therapy and BCVA of ≤ 20/100 and ≥ 20/800 in stratum 2 (parallel, masked study of 1000, 1500, 2250, and 3000 µg of PF-04523655). The primary outcome was safety and tolerability assessment as well as pharmacokinetic profiling following a single IVT injection of PF-04523655. RESULTS: Doses of PF-04523655 ≥ 400 µg were generally detectable in the plasma at 1, 4, and 24 h post-injection. And all doses were below the lowest level of quantification by day 14. A single IVT injection of 50 to 3000 µg of PF-045237655 was generally safe and well tolerated over 24 months. There were no dose-limiting toxicities. CONCLUSION: A single IVT injection of PF-0523655 ≤ 3000 µg seems safe and well tolerated in eyes with neovascular AMD.

Safety, tolerability, and bioavailability of topical SAR 1118, a novel antagonist of lymphocyte function-associated antigen-1: a phase 1b study.

PURPOSE: A growing body of evidence points to a role for inflammation mediated by lymphocyte function-associated antigen-1 (LFA-1) and its ligand intercellular adhesion molecule-1 in the pathogenesis of diabetic macular oedema. This phase 1b clinical trial assessed the safety, tolerability, and pharmacokinetics of topically administered SAR 1118, a novel LFA-1 antagonist, in human subjects. METHODS: In this prospective, randomized, double-masked trial, 13 subjects scheduled for vitrectomy received one of three concentrations of topical SAR 1118 (0.1, 1.0, or 5.0%) twice daily for 1 week before surgery. Undiluted aqueous and vitreous samples were collected at surgery and analysed for the concentration of the medication. RESULTS: All subjects completed the entire course of medication. The only adverse events reported were instillation site irritation (4/13, 31%) and dysgeusia (3/13, 23%). These were mild and transient, occurring at the highest dose. Mean concentrations (ng/ml) of SAR 1118 in the aqueous humour were 0.25, 37.2, and 101.1 for the 0.1%, 1.0%, and 5.0% dose groups, respectively. SAR 1118 was below the level of detection (0.5 ng/ml) for all vitreous samples except in a single subject who had a history of prior vitrectomy and a dislocated intraocular lens. CONCLUSIONS: Topical SAR 1118 was safe and well tolerated, and dose-dependent levels of drug were detected in aqueous. However, vitreous levels were below the threshold of detection with the concentrations tested. Further investigation of this medication for posterior segment applications would require intravitreal delivery or chemical modification of the drug.

Spectral- and time-domain optical coherence tomography measurements of macular thickness in normal eyes and in eyes with diabetic macular edema.

PURPOSE: To report macular thickness values in normal eyes and eyes with diabetic macular edema (DME) using time-domain (TD) and spectral-domain (SD) optical coherence tomography (OCT), and to derive a conversion equation. METHODS: The index study was a prospective investigation conducted on 80 eyes from 40 normal subjects and 130 eyes from 118 patients with DME seen in our clinic. Retinal thickness values from the central 1 mm of the macula and surrounding four ETDRS subfields were acquired using TD-OCT (Stratus OCT) and SD-OCT (SPECTRALIS HRA+OCT). Measurements of the central (C) subfield from both devices were used to derive a conversion equation. The equation was used to predict SD-OCT values using measurements from TD-OCT. Agreement between predicted and actual SD-OCT measurements was assessed. RESULTS: In normal eyes, the mean difference between TD-OCT and SD-OCT measurements of the C subfield was 76 µm (CI(95)=74 and 77, respectively). The conversion equation, y=1.029x+72.49, was derived. In eyes with DME, using the equation, SPECTRALIS-predicted values were 5% higher than actual measurements, with 95% of predicted values falling within 9% of the actual measurements. Relocating SD-OCT grids to match the location on TD-OCT resulted in predicted values falling within 7% of actual measurements. CONCLUSIONS: The percent difference between actual thickness measurements from SPECTRALIS and predicted thickness measurements, using the conversion equation, was within reported limits of repeatability of Stratus in eyes with DME. Our equation may help correlate OCT values from both devices in standard care and clinical trials for DME.

Reactivating HIF prolyl hydroxylases under hypoxia results in metabolic catastrophe and cell death.

Cells exposed to low-oxygen conditions (hypoxia) alter their metabolism to survive. This response, although vital during development and high-altitude survival, is now known to be a major factor in the selection of cells with a transformed metabolic phenotype during tumorigenesis. It is thought that hypoxia-selected cells have increased invasive capacity and resistance to both chemo- and radiotherapies, and therefore represent an attractive target for antitumor therapy. Hypoxia inducible factors (HIFs) are responsible for the majority of gene expression changes under hypoxia, and are themselves controlled by the oxygen-sensing HIF prolyl hydroxylases (PHDs). It was previously shown that mutations in succinate dehydrogenase lead to the inactivation PHDs under normoxic conditions, which can be overcome by treatment with alpha-ketoglutarate derivatives. Given that solid tumors contain large regions of hypoxia, the reactivation of PHDs in these conditions could induce metabolic catastrophe and therefore prove an effective antitumor therapy. In this report we demonstrate that derivatized alpha-ketoglutarate can be used as a strategy for maintaining PHD activity under hypoxia. By increasing intracellular alpha-ketoglutarate and activating PHDs we trigger PHD-dependent reversal of HIF1 activation, and PHD-dependent hypoxic cell death. We also show that derivatized alpha-ketoglutarate can permeate multiple layers of cells, reducing HIF1alpha levels and its target genes in vivo.