Protective Effects of Oral Fructose-1, 6-diphosphate on Liver Injury in Animal Models

Aim To investigate the effects of FDP on different liver injury models to explore the possibility of FDP used as an oral liver protective agent. Methods Chronic liver injury model in rats was induced by carbon tetrachloride （ CCl4 ） ; Acute liver injury model in mice was induced by aminogalactose （GAIN） or lipopolysaccharide （LPS）. Results In CCl4-induced chronic liver injury model, FDP （1 , 4 g·kg^-1·d^-1, q.d., for 10 weeks） significantly lowered ALT, AST,γ-glutamyl transpeptidase （γ-GT）, alkaline phosphatase （ALP）, and total bilirubin （T-BIL） in serum compared with vehicle; simultaneously it evidently elevated abnormal total protein （TP）, albumin （ALB） and total cholesterol （ T-CHO ） levels in serum; it also dose-dependently reduced hydroxyproline contents in hepatic tissue. 4 g·kg^-1·d^-1 of FDP apparently decreased incidence of hepatic cirrhosis, and alleviated pathological changes of liver tissue. In GaiN-induced model, 1.0 - 4. 0 g·kg^-1·d^-1 of FDP （ bid, for 3 d ） significantly lowered alanine aminotransferase （ ALT ） and aspartate aminotransferase （ AST ） levels in serum ; it also decreased liver coefficient. 4. 0 g·kg^-1·d^-1 of FDP significantly alleviated pathological changes of cell ultra-structures. In LPS-induced model, only high dose of FDP （4. 0 g·kg^-1·d^-1, bid, for 12 d） significantly decreased ALT level in serum. Conclusion This study first demonstrated the protective effect of oral FDP on chronic liver injury caused by CCl4, and confirmed its effect on acute liver injury at the same time, suggesting that Long-term oral FDP is efficacious against liver injury induced by different factors and can be used as an oral liver protective agent in clinic.

Repeated febrile convulsions impair hippocampal neurons and cause synaptic damage in immature rats: neuroprotective effect of fructose-1,6-diphosphate

Fructose-1,6-diphosphate is a metabolic intermediate that promotes cell metabolism. We hypothesize that fructose-1,6-diphosphate can protect against neuronal damage induced by febrile convulsions. Hot-water bathing was used to establish a repetitive febrile convulsion model in rats aged 21 days, equivalent to 3–5 years in humans. Ninety minutes before each seizure induction, rats received an intraperitoneal injection of low- or high-dose fructose-1,6-diphosphate（500 or 1,000 mg/kg, respectively）. Low- and high-dose fructose-1,6-diphosphate prolonged the latency and shortened the duration of seizures. Furthermore, high-dose fructose-1,6-diphosphate effectively reduced seizure severity. Transmission electron microscopy revealed that 24 hours after the last seizure, high-dose fructose-1,6-diphosphate reduced mitochondrial swelling, rough endoplasmic reticulum degranulation, Golgi dilation and synaptic cleft size, and increased synaptic active zone length, postsynaptic density thickness, and synaptic interface curvature in the hippocampal CA1 area. The present findings suggest that fructose-1,6-diphosphate is a neuroprotectant against hippocampal neuron and synapse damage induced by repeated febrile convulsion in immature rats.

Effects of fructose-1,6-diphosphate on concentration of calcium and activities of sarcoplosnic Ca^(2+)-ATPase in cardiomyocytes of Adriamycin-treated rats

Objective: To observe the effects of fructose-1,6-diphosphate (FDP) on serum levels of cardiac troponin 1 (cTnl) and creatine kinase-MB (CK-MB), as well as the concentration of calcium in cardiomyocytes (Myo[Ca2+]) and activity of sarcoplosnic Ca2+-ATPase (SRCa2+-ATPase) in Adriamycin (ADR)-treated rats. Methods: Rats were intraperitoneally injected with ADR (2.5 mg/kg every other day for 6 times) and then with different dosages of FDP (every other day for twenty-one times). Bi-antibodies sandwich Enzyme linked immune absorption assay (ELISA) was performed to detect serum level of cTnl. CK-MB was detected by monoclonal antibody, Myo[Ca2+] was detected by fluorescent spectrophotometry and the activity of SRCa2+-ATPase was detected by inorganic phosphate method. Results: FDP (300, 600, 1200 mg/kg) significantly reduced the serum levels of cTnl and CK-MB, while at the same time decreased calcium concentration and increased SRCa2+-ATPase activity in cardiomyocytes of ADR-treated rats (P<0.01). Conclusions: FDP might alleviate the cardiotoxic effects induced by ADR through decreasing calcium level as well as increasing SRCa2+-ATPase activity in cardiomyocytes.

Clinical study of applying fructose-1,6-diphosphate and captopril to enhance the protective effects of cardioplegia solution on ischemic myocardium

In the present experiment,fructose-1,6-diphosphate（FDP）and captopril（Cap）wereadded to the cold potassium cardioplegia solution and the levels of malondialdehyde（MDA）,cre-atine phosphokinase MB（CPK-MB）,thromboxane B（TXB2）and 6-keto-PGF1α in plasma weremeasured during open-heart surgery.Quantitative study of myocardial ultrastructure and obser-vation of cardiac resuscitation were also undertaken.The findings suggested that FDP,especiallywhen combined with Cap could significantly strengthen the protective effects of cold potassiumcardioplegia solution on ischemic myocardium.

The Effect of Fructose-1,6-diphosphate and HTK Solution on Protecting Primary Cardiac Muscle Cells of Rat with Cold Preservation

In this study we tried to investigate the effect of fructose-1,6-diphosphate and HTK solution on protecting primary cardiac muscle cells of rat with cold preservation. The primary cardiac muscle cells of rat were cultured in vitro with four preservation solutions respectively: 0.9 % sodium chloride solution (group A), FDP (group B), HTK solution (group C) and a mixture of FDP and HTK solution (group D). The cells were preserved for 6, 8 and 10 h at 0-4 ℃. The values of AST and LDH-L and the Na+-K+ ATPase activity in cardiac muscle cells were detected, and the survival rate of cardiac muscle cells was detected with trypan blue staining. The values of AST and LDH-L in group C and group D were remarkable lower those in group A and group B (P<0.001), while the Na+-K+ ATPase activity and the survival rate of cells in group C and group D were much higher than those in group A and group B (P<0.001). The values of AST and LDH-L after 6 hours in group D decreased much more than those in group C (P<0.01), while the Na+-K+ ATPase activity and the survival rate of cells in group D improved more than those in group C (P<0.01). Both of the HTK solution and the mixture of HTK and FDP solution have an evident effect on protecting the primary cardiac muscle cells of rat in vitro with cold preservation, Compared with the HTK solution, the mixture solution has a better short-term protective effect.

A New Method of Crystallization of Octahydro Trisodium Salt of Fructose- 1,6-diphosphate

In order to overcome the elementary heterogeneous nucleation whileoctahydro trisodium salt of fructose- 1, 6-diphosphate (FDPNa_3·8H_2O) is crystallized with ethanol precipitation at low temperature,a new crystallization method with alcohol precipitation combined withsalt precipitation has been presented. The ethanol-sodium ac- etatesystem for crystallization of salt of fructose-1, 6-diphosphate isbased on the mechanism of crystallization of FDPNA_3·8H_2O in theethanol-low temperature system. It is found that crystal size may becontrolled by regulating Temperature of pH value of solution in thecrystallization process, and the crystal yield increases to 95/100from 78/100 Which obtained in the ethanol-low temperature system.

Fructose-1,6-diphosphate-added total parenteral nutrition in septic animals and stressed patients

Objective To investigate the roles of fructose-1,6-diphosphate(FDP)-added total parenteral nutrition (TPN)in septic animals and stressed patients.Methods Thirteen adult dogs were randomly assigned to one of two study groups 6 hours after the induction of severe intra-abdominal infection.Group TPN(n =6)received 70 kcal· kg-1· d-1 of nonprotein calorie(NPC)and 0.56 g· kg-1· d-1 of nitrogen.1 g/kg of FDP was also infused to the animals in group TPN + FDP(n = 7)everyday.In the clinical study,the control group received routine TPN,while the study group(n = 16)was treated with TPN plus FDP(5 g,two times a day)for 7 days.Results In dogs with TPN support,plasma ATP levels were not changed significantly,while the value in the TPN + FDP group increased significantly from 0.18 μmol/L to 0.46 μmol/L at 24 h and 0.51 μmol/L at 48 h(P ＜ 0.01).Muscular ATP increased markedly in the TPN + FDP group.Muscular creatine phosphate alues were not significantly changed in the TPN group,but the values increased in the TPN + FDP group from 4.06 μmol/g·wt at the beginning to 4.93 μmol/g· wt at 24 h and 5.60 μmol/g·wt at 48 h(P ＜ 0.05),with a cytochrome oxidase increase in immunohistochemistry stain.In the clinical study,plasma ATP levels increased and urinary 3-methylhistidine production significantly decreased with an improved value for positive accumulative nitrogen balance in the FDP-infused group.Conclusion Our results suggest that total parenteral nutrition support with the supplement of fructose-1,6-diphosphate has a positive role in body energy production and protein metabolism in septic animals and stressed patients.

PRODUCTION OF FRUCTOSE-l,6-DIPHOSPHATE(FDP) BY PERMEABILIZED SACCHAROMYCES CEREVISIAE AND A KINETIC MODEL FOR FDP ACCUMULATION

Permeable yeast cells were used in the batch production of fructose-1,6-diphosphate(FDP).The optimum reaction conditions were reported to be:reaction temperature 30℃,tolueneconcentration 8%(V/V),and initial ratio of glucose to inorganic phosphorus(Pi)10:1.Addition ofAMP was found to be very beneficial to the FDP production.A multienzyme system model for FDPaccumulation was developed,in which FDP was regarded as a substrate of phosphor-fructokinase(PFK),to simulate the activation effect of FDP on PFK.The model simulations were in good agree-ment with the experimental data.

Fructose 1,6-diphosphate alleviates myocardial ischemia reperfusion injury in rats through JAK2/STAT3 pathway

Objective: To study the effect of fructose 1,6-diphosphate(FDP) on myocardial ischemia reperfusion injury in rats and its molecular mechanism.Methods: Male SPF SD rats were selected as experimental animals and randomly divided into four groups.Sham group received sham operation, I/R group were made into myocardial ischemia reperfusion injury models, FDP group were made into myocardial ischemia reperfusion injury models and then were given FDP intervention, and FDP+AG490 group were made into myocardial ischemia reperfusion injury models and then were given FDP and JAK2 inhibitor AG490 intervention.Results: CK, CK-MB, c Tn I and LDH contents in serum as well as Bax and Caspase-3 protein expression in myocardial tissue of I/R group were significantly higher than those of Sham group whereas Bcl-2, p-JAK2 and p-STAT3 protein expression in myocardial tissues were significantly lower than those of Sham group; CK, CK-MB, c Tn I and LDH contents in serum as well as Bax and Caspase-3 protein expression in myocardial tissue of FDP group were significantly lower than those of I/R group whereas Bcl-2, p-JAK2 and p-STAT3 protein expression in myocardial tissue were significantly higher than those of I/R group; CK, CK-MB, c Tn I and LDH contents in serum as well as Bax and Caspase-3 protein expression in myocardial tissue of FDP+AG490 group were significantly higher than those of FDP group whereas Bcl-2 protein expression in myocardial tissue was significantly lower than that of FDP group.Conclusion: FDP could reduce the myocardial ischemia reperfusion injury in rats by activating the JAK2/STAT3 pathway.

Cloning of a NaCl-induced fructose-1,6-diphosphate aldolase cDNA from Dunaliella salina and its expression in tobacco

Using Rapid Amplification of cDNA ends (RACE) technique, the full-length cDNA en-coding a NaCl-induced fructose-1, 6- diphosphate aldolase (DsALDP) was obtained. It was shown that the DsALDP had a relatively high homology (66%—73%) to chloroplast fructose-1, 6-diphos- phate aldolase (AldP) in many plants according to their amino acid sequences. The phylogenetic analysis further confirmed that AldP in alga is the nearest to DsALDP. As to its expression pattern, DsALDP was de novo synthesized by NaCl induction. Its expression level was significantly changed with inducing time. After the selected DsALDP cDNA subcloned into a binary vector pBI121, the new construct was introduced into tobacco by Agrobacterium tumefaciens. The results of Southern blot and RT-PCR analysis of four transgenic T1 plants indicated that DsALDP was integrated into genome of these transgenic plants and effectively expressed. Aldolase activities have been detected in T1-1, T1-2 and T1-3 plants by bioassay under 100—200 mmol/L NaCl. It was also observed that proline contents in them were differentially increased.

Overexpression of Brassica napus cytosolic fructose-1,6-bisphosphatase and sedoheptulose-1,7-bisphosphatase genes significantly enhanced tobacco growth and biomass

Elevated activities of cytosolic fructose-1,6-bisphosphatase(cyFBPase) and sedoheptulose-1,7-bisphosphatase(SBPase)are associated with higher yields in plants. In this study, the expression levels of the cyFBPase and SBPase genes were increased by overexpressing rape(Brassica napus) cDNA in tobacco(Nicotiana tabacum) plants. The transgenic plants coexpressing cy FBPase and SBPase(TpFS), or expressing single cy FBPase(TpF) or SBPase(TpS) had 1.77-, 1.55-, 1.23-fold cyFBPase and 1.45-, 1.12-, 1.36-fold SBPase activities as compared to the wild-type(WT), respectively. Photosynthesis rates of TpF, TpS and TpFS increased 4, 20 and 25% compared with WT plants. The SBPase and cyFBPase positively regulated each other and functioned synergistically in transgenic tobacco plants. In addition, the sucrose contents of the three transgenic plants were higher than that of WT plants. The starch accumulation of the TpFS and TpS plants was improved by 53 and 37%, but slightly decreased in TpF plants. Moreover, the transgenic tobacco plants harbouring SBPase and/or cyFBPase genes showed improvements in their growth, biomass, dry weight, plant height, stem diameter, leaf size,flower number, and pod weight. In conclusion, co-expression of SBPase and cyFBPase may pave a new way for improving crop yield in agricultural applications.

Status epilepticus due to fructose-1,6-bisphosphatase deficiency caused by FBP1 gene mutation

Introduction:Fructose-1,6-bisphosphatase (FBPase) deficiency is a rare inherited disorder in gluconeogenesis,characterized by hypoglycemia,ketonuria,metabolic acidosis and convulsions.Case presentation:We describe two brothers with FBPase deficiency.The proband developed severe hypoglycemia and progressed to status epilepticus,and the brother showed slightly hypoglycemia with a good prognosis.Whole exome sequencing (WES) identified compound heterozygous variants [c.333+1333+2delinsTC and c.490G>A (p.Gly164Ser)] in fructose-1,6-bisphosphatase 1 gene in the two brothers,which were inherited from the father and the mother,respectively.Conclusion:Genetic analysis provided a solid basis for a definite diagnosis and the determination of precision therapies for the patient.

The effect of stunned myocardium on heart function and the protection of fructose－1，6－diphosphate on it

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Protective Effects of Sodium Magnesium Fructose Diphosphate on Brain Damage of Rats Subjected to Focal Cerebral Ischemia and Reperfusion

Objective: To study the effects of sodium magnesiusm fructose diphosphate(FDPM) on brain damage of rats after ischemia-reperfusion. Methods: Rats were subjected to cerebral ischemia-reperfusion induced by inserting a nylon thread into internal carotid artery to block the origin of middle cerebral artery and removing the thread later. FDPM (400 mg·kg -1), fructose-1,6-diphosphate (FDP, 400 mg·kg -1)and magnesium sulfate (MgSO 4, 30 mg·kg -1) were administrated 10 min after the onset of ischemia. Neurological scale, brain infarct area, Malondialdehyde(MDA) content and histopathological changes of brain tissue were studied. Results: FDPM decreased neurological scale, diminished brain infarct area, reduced MDA content and relieved histopathological change of rat brain tissue subjected to ischemia-reperfusion. These effects were more powerful than that of FDP or MgSO 4. Conclusions: It is suggested that FDPM markedly prevented rats against brain damage after cerebral ischemia-reperfusion, and its effect was better than that of FDP or MgSO 4.

Vacuole import and degradation pathway: Insights into a specialized autophagy pathway

Glucose deprivation induces the synthesis of pivotagluconeogenic enzymes such as fructose-1,6-bisphos-phatase, malate dehydrogenase, phosphoenolpyruvatecarboxykinase and isocitrate lyase in Saccharomycescerevisiae. However, following glucose replenishment,these gluconeogenic enzymes are inactivated and de-graded. Studies have characterized the mechanismsby which these enzymes are inactivated in response toglucose. The site of degradation of these proteins hasalso been ascertained to be dependent on the dura-tion of starvation. Glucose replenishment of short-termstarved cells results in these proteins being degradedin the proteasome. In contrast, addition of glucose tocells starved for a prolonged period results in theseproteins being degraded in the vacuole. In the vacuoledependent pathway, these proteins are sequestered inspecialized vesicles termed vacuole import and degra-dation (Vid). These vesicles converge with the endo-cytic pathway and deliver their cargo to the vacuolefor degradation. Recent studies have identified thatinternalization, as mediated by actin polymerization, isessential for delivery of cargo proteins to the vacuolefor degradation. In addition, components of the targetof rapamycin complex 1 interact with cargo proteins during glucose starvation. Furthermore, Tor1p dissoci-ates from cargo proteins following glucose replenish-ment. Future studies will be needed to elaborate on the importance of internalization at the plasma membrane and the subsequent import of cargo proteins into Vid vesicles in the vacuole dependent degradation pathway.