Localized leptin release may be an important mechanism of curcumin action after acute ischemic injuries.

BACKGROUND: Previous studies have demonstrated that both curcumin and leptin are protective factors against acute injuries. Here, we investigated whether leptin and its signaling pathway mediate the protective effects of curcumin. METHODS: A solid dispersion of curcumin-polyvinylpyrrolidone K30 was prepared and administered intraperitoneally. In vivo intestinal ischemia/reperfusion (I/R) injury in mice determined the effects of curcumin administration on inflammation, oxygen radical production, and leptin expression. In vitro studies using the venous epithelial cell line ECV-304 examined hypoxia/reoxygenation-induced leptin expression and release after curcumin administration. Furthermore, the effects on the leptin-regulated ERK1/2 and p38 MAPK signaling pathways were also explored. RESULTS: Intestinal I/R induced marked bowel injuries. Curcumin treatment significantly improved animal survival and reduced the pathologic injuries in the intestines. Furthermore, the elevated intestinal water content and levels of malondialdehyde, interleukin 1ß (IL-1ß) and IL-6 were significantly decreased, but levels of superoxide dismutase increased. Interestingly, we found that the decreased leptin and its receptor Ob-Rb were restored by curcumin administration. In addition, in vitro studies showed that curcumin increased leptin expression and release after hypoxia/reoxygenation-induced cell injuries. Moreover, curcumin treatment restored decreased ERK1/2 phosphorylation (p-ERK1/2) and inhibited overactive p38 (p-p38) after injuries, and the effect was reversed by a leptin-specific antibody or Ob-R blocker. CONCLUSION: These data suggest that leptin and Ob-Rb-dependent ERK and p38 MAPK signaling pathways may be involved in curcumin protection against intestinal I/R injury, and leptin may be a potential target of curcumin in intestinal I/R injury and other related acute diseases.

[Preliminary investigation of the changes and mechanism of Leptin after myocardial ischemia/reperfusion injury].

OBJECTIVE: To explore the effect of rat myocardial ischemia/reperfusion (I/R) injury on serum Leptin, endothelin (ET), C-reactive protein (CRP) and myocardial Leptin expression, and discuss the role of Leptin in myocardial I/R injury. METHODS: Fifty Sprague-Dawley (SD) rats were randomly divided into sham-operation, ischemia and I/R 1, 2, 3 hours groups, with 10 rats in each group. Anterior descending artery of the left coronary artery was ligated for 45 minutes and released for 1, 2 and 3 hours to establish myocardial I/R model, and the said artery of the rats in sham-operation group was not ligated. Blood from left femoral artery was collected at different time points, and serum Leptin, ET and CRP contents were detected. Myocardial tissue was harvested, and stained with hematoxylin-eosin (HE) and immunohistochemistry for its observation of the myocardial pathological changes and Leptin protein expression. RESULTS: Serum Leptin content (µg/L) of ischemia group was significantly lower than that of sham-operation group (4.69±1.67 vs. 6.48±2.02, P<0.05); as the reperfusion time was prolonged, serum Leptin level increased gradually, and the level of I/R 3-hour group recovered to that before injury [(6.59±2.58) µg/L]. ET content (ng/L) of ischemia group was significantly higher than that of sham-operation group (110.58±37.86 vs. 80.74±34.43, P<0.05), the levels of ET in I/R 1, 2 and 3 hours groups were significantly lower than those of ischemia group (35.87±13.56, 31.98±10.88, 34.56±14.37 vs. 110.58±37.86, all P<0.05). CRP content (mg/L) of ischemia group was significantly higher than that of sham-operation group (13.12±4.82 vs. 3.24±1.72, P<0.01); as the reperfusion time was prolonged, serum CRP level increased gradually, and the levels of I/R 1, 2 and 3 hours groups were significantly higher than those of ischemia group (18.37±6.48, 24.30±9.51, 27.08±8.32 vs. 13.12±4.82, all P<0.05). Pathological examination showed that there was necrosis of ischemic myocardial cells in ischemia group, with mild congestion and edema in interstitial spaces. After I/R injury, the myocardial cells showed coagulative necrosis, and there was severe congestion of myocardial interstitial. Immunohistochemistry results showed that there was a tendency of decrease in Leptin protein expression in the early phase but increase in the late phase after the injury. CONCLUSION: Leptin content in the serum and myocardial tissue decreases significantly in the early phase after myocardial I/R but increases gradually in the rehabilitative phase, suggesting that Leptin maybe a stress protective factor against I/R-induced myocardial injury. There is a possible association between Leptin and the early increase followed by a delayed decrease of ET as well as the increase of CRP.

Endogenous leptin fluctuates in hepatic ischemia/reperfusion injury and represents a potential therapeutic target.

AIM: To evaluate the role of leptin in the internal disorders during hepatic ischemia/reperfusion injury. METHODS: A rat model of 70% hepatic ischemia/reperfusion injury was established, with groups of sham-operation (Sham), 60 min ischemia/60 min reperfusion (I60'R60'), I60'R150', I60'R240' and I60'R360'. Serum leptin was detected by a self-produced radioimmunoassay; serum glucose, total anti-oxidation capacity, myeloperoxidase, alanine transaminase and diamine oxidase were determined by relevant kits, while histological alterations and protein levels of leptin in the lung, liver and duodenum were examined by hematoxylin-eosin staining and immunohistochemistry. Spearman's rank correlation between leptin and other variables or grading of tissue impairment were analyzed simultaneously. RESULTS: Serum leptin in I60'R360' was significantly higher than in Sham and I60'R240' groups (both P < 0.05), serum glucose in I60'R360' was higher than in Sham and I60'R150' (both P < 0.05), and serum total anti-oxidation capacity in I60'R240' and I60'R360' were higher than in Sham (both P < 0.05) and I60'R150'groups (both P < 0.01). Serum myeloperoxidase in groups of I60'R240' and I60'R360' were lower than in I60'R150'group (both P < 0.05), serum alanine transaminase in the four reperfusion groups were higher than in the Sham group (all P < 0.05), while serum DAO in I60'R360' was lower than in I60'R60' (P < 0.05). Histological impairment in the lung, liver and duodenum at the early phase of this injury was more serious, but the impairment at the later phase was lessened gradually. Protein levels of leptin in the lung in the four reperfusion groups were significantly lower than in the Sham group (all P < 0.01), decreasing in the order of I60'R150', I60'R60', I60'R360' and I60'R240'; the levels in the liver in I60'R60' and I60'R240' were higher than in the Sham group (both P < 0.01), while the levels in I60'R240' and I60'R360' were lower than in I60'R60' (both P < 0.01); the levels in duodenum in I60'R240' and I60'R360' were higher than in Sham, I60'R60' and I60'R150' (all P < 0.01), while the level in I60'R150' was lower than in I60'R60' (P < 0.05). There was a significantly positive correlation between serum leptin and alanine transaminase (ρ = 0.344, P = 0.021), a significantly negative correlation between the protein level of leptin in the lung and its damage scores (ρ = -0.313, P = 0.036), and a significantly positive correlation between the protein level of leptin in the liver and its damage scores (ρ = 0.297, P = 0.047). CONCLUSION: Endogenous leptin fluctuates in hepatic ischemia/reperfusion injury, exerts a potency to rehabilitate the internal disorders and represents a potential target for supportive therapy.

[Effects of leptin on apoptosis of rat cerebral astrocytes with ischemia/hypoxia injury].

OBJECTIVE: To investigate the effect of leptin on apoptosis of rat cerebral astrocytes with ischemia/ hypoxia injury and its mechanism. METHODS: The cerebral astrocytes with ischemic/hypoxia injury were induced in neonatal SD rats. The cellular viability of injury of astrocytes was detected by MTT assay. The apoptosis of astrocyte were detected with Annexin V-FITC kit. The effect of leptin on the expression of apoptosis factor bcl-2, bax, caspase-3 was detected by RT-PCR and Western blot. RESULTS: Compared with the ischemia group, the cellular viability of leptin intervention group increased significantly (P < 0.01), while the astrocytes apoptosis of leptin intervention group decreased significantly (P < 0.01). The mRNA and protein expression level of antiapoptosis factor bcl-2 in leptin intervention group was much higher than that of ischemia group (P < 0.01), whereas the mRNA and protein expression of bax and caspase-3 was much lower than that of ischemia group (P < 0.01). CONCLUSION: Leptin could significantly decrease the apoptosis of astrocytes with ischemia/hypoxia injury, and it i relevant to the increase of bcl-2 expression and the decrease of bax caspase-3 expression level.

Heart-type fatty acid-binding protein is a useful marker for organ dysfunction and leptin alleviates sepsis-induced organ injuries by restraining its tissue levels.

Heart-type fatty acid-binding protein (H-FABP) is widely distributed and has been used to diagnose certain diseases. However, its alteration during infection-evoked organ dysfunction, and the potential association between leptin and it in injury or infection has not been investigated. In the current study, serum H-FABP, leptin, C-reactive protein and interleukin-1beta in the patients with pulmonary infection-induced multiple organ dysfunction were detected. Moreover, a mouse model of sepsis was established, and serum alanine transaminase, uric acid, tissue H-FABP, myeloperoxidase, superoxide dismutase activity and histological alterations in lung and intestine were investigated. Serum H-FABP and leptin increased simultaneously and significantly in the patients, and leptin alleviated pulmonary and intestinal injuries by restraining tissue H-FABP secretions in the mouse model of sepsis. Other investigated variables showed different but independent alterations. In conclusion, H-FABP represents a useful diagnostic marker for organ dysfunction, and its association with leptin will be a novel target for emergency aid.

[Role of leptin in hepatic ischemia/reperfusion-induced hepatic injury].

UNLABELLED: OBJECTIVE; To study the changes of leptin after hepatic ischemia/reperfusion (H-I/R) and its effects on H-I/R-induced hepatic injury. METHODS: A 70% H-I/R model of rats was established. The rats were divided into groups with different reperfusion times and sham-operation group. Radioimmunoassay was applied to measure protein levels of leptin in serum and adipose tissues of the rats. Enzyme-colorimetry was used to detect serum alanine transaminase. Hematoxylin-eosin staining and immunohistochemistry were applied to investigate pathological variations and protein expressions of leptin in livers, respectively. RT-PCR was used to detect leptin mRNA expressions in adipose tissues and livers. RESULTS: Compared with the sham-operation group, serum leptin increased significantly in the 60 min ischemia/360 min reperfusion (I60' R360') group; protein level of leptin in adipose tissues increased significantly in the I60'R60' group; serum alanine transaminase increased significantly in all of the four reperfusion groups; protein expressions of leptin in livers increased significantly in the I60'R60' and 160'R240' groups; leptin mRNA expression in adipose tissues decreased significantly in the I60'R150' group; leptin mRNA expression in livers increased significantly in the 160'R60' group; leptin mRNA expressions in livers decreased significantly in the I60'R150', I60'R240' and I60'R360' groups. Pathological investigation showed that hepatic impairments at the early phase of H-I/R were more serious. The impairments at the later phase lessened gradually. CONCLUSION: The change of leptin expressions after H-I/R may be a protective factor to withstand H-I/ R-induced hepatic injury.

[Changes of leptin levels in serum and myocardium after myocardial ischemia/reperfusion injury].

AIM: To explore the effect of rat myocardial ischemia/reperfusion injury on leptin levels in serum and myocardium, and discuss the role of leptin in myocardial ischemia/reperfusion injury. METHODS: A myocardial ischemia/reperfusion injury model of rats was established, serum lactate dehydrogenase (LDH) and leptin levels were detected, and histopathological changes and leptin expressions in myocardium were investigated by hematoxylin-eosin staining and immunohistochemistry, respectively. RESULTS: Serum LDH of ischemia and reperfusion groups increased significantly (P < 0.05), suggesting the model was successfully established and a certain degree of local myocardial injury was induced. Serum leptin of ischemia group (6.34 +/- 2.49) ng/ml was significantly lower than control group (7.50 +/- 2.93 ng/ml, P <0.05). Leptin levels recovered gradually after reperfusion, reached (8.32 +/- 1.74)ng/ml at 2 h after reperfusion, which recovered to the level before injury (8.38 +/- 2.56) ng/ml, and showed a trend to increase as reperfusion time was elongated. Immunohistochemistry results showed that as compared with sham-operation group, myocardial leptin protein expressions of the other four groups were all significantly lower (P < 0.01), and decreased in order by 45 min ischemia/1 h reperfusion, 45 min ischemia/3 h reperfusion, 45 min ischemia and 45 min ischemia/2 h reperfusion. CONCLUSION: Leptin level in the blood decreases significantly at the early 45 min after myocardial ischemia/reperfusion injury, and its expression in myocardium also decreases significantly. There may be a certain relationship between the pathological injury of myocardium and the changes of leptin.

[Distribution of leptin expression and its effect on the recovery of sepsis-induced internal disorders].

OBJECTIVE: To explore the distribution of leptin expression and the effect of sepsis on leptin protein and mRNA levels. METHODS: Vital organ samples including hypothalamus, lung, liver, spleen, stomach, duodenum, kidney, epididymal fat pad and testis of normal rats were collected. The mRNA expressions of leptin in those samples were determined by RT-PCR. The sepsis rat model induce by cecal ligation and perforation (CLP) was established, setting groups of sham-operation, CLP model, CLP + intralipid injection, CLP + estradiol injection and CLP + insulin injection, as the latter three groups were set to intervene energy metabolism and neuroendocrine function. Radioimmunoassay was applied to measure serum leptin concentrations in each group at 12 h after injury, while RT-PCR was also used to detect Leptin mRNA expressions in hypothalamus, fat and lung after injury. RESULTS: Leptin mRNA expressions were confirmed in all the above nine vital organs, with the highest in kidney but the lowest in testis. The serum leptin level showed no significant difference between sham operation group and other four groups. Compared with sham operation group, the Leptin mRNA level in CLP group decreased significantly in hypothalamus, fat and lung, while that in the other three groups showed different changes. The effect of intralipid on Leptin mRNA expression was found to be a dual-direction pattern, with central stimulation but peripheral inhibition. CONCLUSION: Leptin is widely expressed in multiple vital organs, and it may be a protective factor to promote recovery of sepsis-induced internal disorders.

Leptin protects vital organ functions after sepsis through recovering tissue myeloperoxidase activity: an anti-inflammatory role resonating with indomethacin.

In this research, the role of leptin on sepsis-induced organ dysfunction was evaluated. Making use of a mice sepsis model, changes of alanine transaminase and uric acid in serum, myeloperoxidase activity, leptin levels and histological alterations in heart, lung, liver and kidney were determined. Results showed that sepsis induced significantly higher levels of serum alanine transaminase and uric acid, decreased tissue myeloperoxidase activity and leptin levels, and triggered distinct histological alterations. However, leptin and indomethacin injections reversed those impairments at 6h and/or 12h after injury. These data reveal a protective role of both leptin and indomethacin on vital organ functions after sepsis by recovering tissue myeloperoxidase activity.

[p38 MAPK/cPLA2 pathway mediates interleukins release in inflammatory cell model].

OBJECTIVE: To explore the underlying mechanism of lipopolysaccharide (LPS)-induced interleukin-1 beta (IL-1 beta) and IL-6 release via p38 mitogen-activated protein kinase (MAPK) pathway in HeLa cells for further identification of involved down-stream message factors. METHODS: HeLa cells were challenged with LPS to reproduce inflammatory cell model. The activity or expression of p38 MAPK, cytosolic phospholipase A(2) (cPLA(2)) and COX-2, was inhibited with pretreatment of inflammatory HeLa cells with the inhibitors (SB203580, AACOCF(3), NS-398) or transfected with the cPLA(2) antisense oligonucleotide (SK7111), then the activities and/or expression of p38 MAPK, cPLA(2), COX-2, and relationship with levels of IL-1 beta and IL-6 supernatants were determined in each group. RESULTS: SB203580 obviously down-regulated the activities of p38 and cPLA(2), as well as the release of IL-1 beta and IL-6. AACOCF(3) and SK7111 blocked dose-dependently the activity or expression of cPLA(2), IL-1 beta and IL-6 production. However, the expression of COX-2 could hardly be detected in HeLa cells, even after LPS treatment. At the same time, pre-treatment with NS-398 had no effect on IL-1 beta, IL-6 production. CONCLUSION: p38 MAPK/cPLA(2) pathway mediates the expression of IL-1 beta and IL-6 resulting from LPS treatment of HeLa cells, while COX-2, as a down-stream enzyme of cPLA(2) has no effect in this process.

[Leptin decreases post-septic pulmonary and intestinal FABP levels and its mechanism].

AIM: To detect the effect of sepsis on fatty acid binding proteins (FABP) levels and corresponding enzymes in lung and intestine of mice, and to explore the role for FABP in acute inflammation. METHODS: A sepsis model of mice made with cecum deligation and perforation was established, and a radioimmunoassay for FABP and 96-well spectrophotometry assays for myeloperoxidase (MPO) and superoxide dismutase (SOD) which were related with clearance of free radicals,were used to detect their levels in lung and intestine homogenized fluids. Hematoxylin-eosin stain was used simultaneously to check the histopathologic chanes of both tissues. RESULTS: Compared with sham group (108.11 +/- 94.03 and 67.22 +/- 19.47 ng/ml) 6 h and 12 h after sepsis, FABP levels in lung and intestine were significantly higher (204.98 +/- 70.72 and 154.29 +/- 60.14 ng/ml), respectively. Twelve hours after leptin (0.1 mg/kg i p) and indomethacin (2 mg/kg i p) injection, lung FABP level decreased and was lower than septic group (P < 0.05). Moreover, 12 h after sepsis intestinal FABP increased, but it decreased after leptin injection (419.80 +/- 80.06 vs 191.09 +/- 96.75 ng/ml), while indomethacin injection had no such effect. MPO and SOD activities in lung and intestine changed accordingly with time after sepsis, the effect of leptin and indomethacin injections on it had no significant correlation with FABP changes. CONCLUSION: Leptin can protect vital organ functions such as lung and intestine after sepsis, as FABP levels, the cellular injury marker, were significantly lower than groups without injection. And this effect might have no correlation with the clearance factors of oxygenic free radicals such as MPO and SOD.

[Leptin protects sepsis-induced renal injury and research for its mechanism].

OBJECTIVE: To detect the effect of sepsis on renal function and corresponding enzymes in mice, and to explore the role of leptin in acute inflammation. METHODS: Sepsis was reproduced by cecum ligation and puncture in mice. Serum uric acid (UA) and four enzymes related with synthesis of free radicals in kidney homogenized fluids, myeloperoxidase (MPO), glutathione-S-transferase (GST), xanthine oxidase (XOD) and superoxide dismutase (SOD) were determined with spectrophotometry, and leptin level in kidney was detected by radioimmunoassay. Histopathologic changes in kidney were observed with hematoxylin-eosin staining. RESULTS: Twelve hours after leptin (0.08 mg/kg, i.p.) and indomethacin (8 mg/kg, i.p.) injection, serum UA was significantly decreased [(295.79+/-80.86) micromol/L and (281.78+/-46.35) micromol/L, respectively, vs. sepsis group (474.03+/-75.22) micromol/L]. At the same time, renal leptin levels in leptin injection group [(196.00+/-134.30) microg/g] 12 hours after sepsis and in indomethacin injection group [(169.30+/-132.00) microg/g] 6 hours after sepsis were also significantly higher than sepsis group [(61.65+/-27.29) microg/g]. Six and 12 hours after leptin and indomethacin injection, renal MPO, GST, XOD and SOD activities were affected to certain extent, as the results were not completely inhibited or enhanced. Nevertheless, leptin and indomethacin could promote scavenge and deactivation of free radicals. CONCLUSION: Low dose leptin can ameliorate sepsis-induced renal injury, which may be related with scavenge and deactivation of free radicals in renal cells, and this mechanism is similar with that of indomethacin.

[Effect of intestinal ischemia/reperfusion injury on protein and mRNA levels of orexin-A].

OBJECTIVE: To investigate the effect of intestinal ischemia/reperfusion (I/R) injury on orexin-A levels in plasma and hypothalamus, and to find out the role of orexin-A in acute inflammatory responses. METHODS: Fifty-four SD rats were randomly divided into a sham-operation group and 5 experiment groups. Then we established the intestinal I/R injury model of rats and setup the 5 experiment groups of 60 min ischemia followed by different periods of time for reperfusion. Protein levels of orexin-A in plasma and hypothalamus were measured by radioimmunoassay, and the changes of orexin-A mRNA expression in hypothalamus were detected by RT-PCR. RESULTS: By analyses on the orexin-A levels in plasma of rats before and after injury, no significant change was observed in the 5 experiment groups (P > 0.05), and the 5 groups' post-injury orexin-A levels in plasma and hypothalamus were not significantly different from the sham-operation group's (P > 0.05). However, by comparison with the sham-operation group after injury, the experiment groups were found to have orexin-A mRNA levels in hypothalamus significantly decreased step by step from 60 min ishchemia/30 min reperfusion (160' R30') to 160'R150'; the lowest level was seen at 160'R150'; and at 160'R240' and I60'R360', the level recovered slowly, but it was still lower than that seen in the sham-operation group. CONCLUSION: Orexin-A makes a delayed response to intestinal I/R injury and may function as inflammatory cytokine in the metabolic disorders caused by acute inflammation.

[Effect of intestinal ischemia/reperfusion injury on leptin and orexin-A levels].

OBJECTIVE: To explore the effect of intestinal ischemia/reperfusion (I/R) injury on leptin and orexin-A levels in peripheral blood and central secretory tissues, and investigate the roles of leptin and orexin-A in acute inflammatory responses. METHODS: An intestinal I/R injury rat model was established, and the rats were grouped according to duration of the reperfusion time following a 60-min ischemia. Radioimmunoassay was used to examine the protein levels of leptin in the serum and adipose tissue, and the protein levels of orexin-A in the plasma and hypothalamus. Reverse transcriptase-polymerase chain reaction was also performed to detect the mRNA expressions of adipose leptin and hypothalamus orexin-A. RESULTS: Compared with that before injury, serum leptin level of 60-min ischemia with 30-min reperfusion (I60'R30') group decreased significantly and that of I60'R360' increased significantly. Compared with the sham-operation group (sham) after injury, serum leptin level of I60'R360' group increased significantly, and adipose leptin protein levels of I60'R30' and I60'R90' groups decreased significantly, whereas that of I60'R360' group increased obviously. Compared with sham group after injury, adipose leptin mRNA expressions of I60'R30', I60'R240' and I60'R360' groups all increased significantly, while that of I60'R150' showed significant decrease. No significant changes were noted in the protein levels of orexin-A either in the plasma or hypothalamus after I/R injury. In comparison with sham group after injury, hypothalamus orexin-A mRNA expressions of I60'R30' and I60'R90' groups showed gradual but significant decrease, and till 150 min of reperfusion, the expression reached its lowest, followed then by slow recovery at 240 and 360 min, though still remaining significantly lower than that of sham group. CONCLUSION: Leptin and orexin-A have a time-dependent response to intestinal I/R injury, but the former appears to exhibit a faster response, and they may play a certain role in the metabolic disorders of acute inflammation.

[Changes in serum leptin levels in patients with surgically induced stress responses].

OBJECTIVE: To explore the effect of operative trauma induced stress responses on serum leptin levels. METHODS: Serum samples of patients who had undergone resection of hepatic tumors or cholecystectomy were collected, and highly sensitive radioimmunoassay and enzyme-linked immunoadsorbent assay (ELISA) were used to determine serum levels of leptin, granulocyte-clone stimulating factor (G-CSF), C-reactive protein (CRP) and adrenocorticotropin hormone (ACTH) in the blood of these patients. RESULTS: Compared with self-control before operation, serum leptin levels decreased slightly right after an abdominal operation (T0), it reached the highest level 1 day after operation (T1), and began to decrease from 2 days (T2) to 4 days after operation (T4), but the level was still higher than that before operation. Serum leptin levels of patients undergoing laparoscopic operation showed no significant difference when compared with that of laparotomy patients. G-SF levels decreased significantly after operation in both groups, and didn't recover to the levels before operation from T1 to T4. CRP levels slightly decreased in both groups at T0, but increased significantly higher than the levels before operation from T1 to T4. ACTH levels of decreased significantly in laparotomy patients from T0 to T1, and began to recover on T2, while that of laparoscopic operation patients showed no significant difference before and after operation. CONCLUSION: Serum leptin levels of patients increase significantly and constantly subsequent to operative trauma induced stress responses, but this change has no correlation with that of CRP, G-SF and ACTH.

[Effect of long tubular bone fracture on serum levels of leptin, acute phase proteins and biochemical markers for organ functions].

OBJECTIVE: To investigate the effect of long tubular bone fracture (LTBF) on serum levels of leptin, acute phase proteins and biochemical markers for organ functions, and to look for the role of leptin in traumatic inflammatory responses. METHODS: Serum samples of LTBF patients and normal controls were collected, and immunoassays were used to determine serum levels of leptin and three acute phase proteins, including C-reactive protein (CRP), interleukin-1 (IL-1) and IL-2, and 21 biochemical markers for organ and metabolic functions were measured simultaneously with automatic biochemical analyzer. Correlation between leptin and all the markers was then analyzed. RESULTS: Compared with normal control, serum levels of leptin, CRP, IL-1 and IL-2 increased significantly (all P<0.05), with various degrees of changes in the markers for hepatic, cardiac, renal and metabolic functions. Leptin was independent to all the markers investigated, and it seemed to exert its unique roles. CONCLUSION: Leptin increases significantly in LTBF-induced acute traumatic inflammatory response, showing a comparatively strong responsiveness to the stimulation, and it may play a role as an anti-inflammatory cytokine.

[Correlation analysis of increase in serum level of leptin with that of C reactive protein, troponin T and endothelin in patients with acute myocardial infarction].

OBJECTIVE: To determine serum leptin levels in patients with acute myocardial infarction (AMI) and coronary atherosclerosis (CS), and to analyze its correlation with C reactive protein (CRP), troponin T (TnT) and endothelin (ET). METHODS: Serum samples from confirmed AMI and CS patients were collected. Leptin and ET were assayed with high sensitive radioimmunoassay, TnT was determined with automatic biochemical analyser, and CRP was determined with enzyme-linked immunosorbant assay (ELISA). RESULTS: Compared with normal control group, serum leptin, TnT, CRP and ET levels increased significantly (all P<0.01) in AMI patients. Serum levels of other cytokines, except TnT in CS patients, increased significantly compared with normal control group (all P<0.01). Correlation analysis showed that all the changes were not correlated with each other, each being an independent factor. Only serum TnT levels of AMI and CS patients showed a significant difference (P<0.01). CONCLUSION: Serum leptin levels of both AMI and CS patients increase significantly without a significant difference between each other, and there is no correlation for leptin with CRP, TnT and ET.

[Changes of serum leptin level in pulmonary infection-induced multiple organ dysfunction syndrome].

OBJECTIVE: To determine serum levels of leptin and some related cytokines in severely ill patients, including severe pulmonary infection-induced multiple organ dysfunction syndrome (MODS), acute myocardial infarction (AMI) and arrhythmia (AR), and to explore the possible role of leptin in the pathogenesis and diagnosis of MODS. METHODS: Radioimmunoassay was used to determine leptin, fatty acid binding protein (FABP), transferrin (Ferr) and interleukin-1beta (IL-1beta), and enzyme-linked immuno adsorbent assay (ELISA) was used to assess C reactive protein (CRP). RESULTS: Compared with normal individuals, leptin levels in MODS, AMI and AR patients increased significantly (all P<0.01). CRP and IL-1beta levels also increased significantly in MODS, AMI and AR patients, but the changes were more marked (all P<0.05) in MODS patients than in the patients of other two diseases (both P<0.05). Though FABP and Ferr levels of patients in all the three groups of patients showed a trend toward increase, especially in MODS patients, there was no significant difference between them and normal individuals. CONCLUSION: Serum leptin level increases significantly in pulmonary infection-induced MODS patients with a simultaneous increase of CRP and IL-1beta levels, and the result suggests that leptin plays a possible role in the pathogenesis and prognosis of MODS.

Effect of intestinal ischemia-reperfusion injury on protein levels of leptin and orexin-A in peripheral blood and central secretory tissues.

AIM: To explore the effect of intestinal ischemia-reperfusion injury on protein levels of leptin and orexin-A in peripheral blood and their central secretory tissues and to find out the role leptin and orexin-A play in acute inflammatory responses. METHODS: An intestinal ischemia-reperfusion (I/R) injury model of rats was established and rats were divided randomly into six groups: sham-operation group, 60 min ischemia/30 min reperfusion group (I60'R30'), I60'R90', I60'R150', I60'R240' and I60'R360', 9 rats each group. Two highly-sensitive radioimmunoassays for leptin and orexin-A were established and used to check the change of their concentrations in peripheral blood and central secretory tissues before and after intestinal I/R injury. RESULTS: Compared with the serum leptin level before injury, it decreased significantly in I60'R30' group and increased significantly in I60'R360' group; compared to sham-operation group after injury, serum leptin level increased significantly in I60'R360' group; compared to sham-operation group after injury, adipose leptin levels decreased significantly in I60'R30' and I60'R90' groups, while increased significantly in I60'R360' group. There was no significant difference between the expression levels of orexin-A before and after I/R injury. CONCLUSION: Leptin has a time-dependent response and orexin-A has a delayed response to acute inflammatory stimuli such as intestinal I/R injury and they may participate in metabolic disorders in injury as inflammatory cytokines.

Colon-specific drug delivery systems based on cyclodextrin prodrugs: in vivo evaluation of 5-aminosalicylic acid from its cyclodextrin conjugates.

AIM: To investigate the release of cyclodextrin-5-aminosalicylic acid (CyD-5-ASA) in cecum and colon. METHODS: An anti-inflammatory drug 5-ASA was conjugated onto the hydroxyl groups of alpha-, beta- and gamma-cyclodextrins (CyDs) through an ester linkage, and the in vivo drug release behavior of these prodrugs in rat's gastrointestinal tract after the oral administration was investigated. RESULTS: The 5-ASA concentration in the rat's stomach and small intestine after the oral administration of CyD-5-ASA conjugate was much lower than that after the oral administration of 5-ASA alone. The lower concentration was attributable to the passage of the conjugate through the stomach and small intestine without significant degradation or absorption, followed by the degradation of the conjugate site-specific in the cecum and colon. The oral administration of CyD-5-ASA resulted in lower plasma and urine concentration of 5-ASA than that of 5-ASA alone. CONCLUSION: CyD-5-ASA conjugates may be used as prodrugs for colon-specific drug delivery system.