Plasma levels of soluble urokinase plasminogen activator receptor (suPAR) and high-sensitivity C-reactive protein after Roux-en-Y gastric bypass or sleeve gastrectomy: a 1-year prospective observational study.

PURPOSE: Low-grade inflammation in obesity contributes to the development of cardiovascular disease, diabetes mellitus and cancer, and is associated with increased mortality. The purpose of this 1-year prospective observational study was to examine the weight loss effect of bariatric surgery on plasma concentrations of two inflammatory markers, namely high-sensitivity C-reactive protein (hsCRP) and soluble urokinase-type plasminogen activator receptor (suPAR), in patients with obesity. METHODS: Sixteen subjects without obesity and 32 patients with obesity class III, who had already settled upon Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) were included in the study. Subjects without obesity were examined once, at baseline; patients with obesity were examined preoperatively (baseline) and 3, 6 and 12 months postoperatively. RESULTS: Plasma suPAR and hsCRP concentrations at baseline were higher in patients with obesity than in lean participants (2.68 ± 0.86 vs 1.86 ± 0.34 ng/mL, p < 0.001 and 9.83 ± 9.55 vs 1.36 ± 1.95 mg/dL, p < 0.001). Levels of suPAR following bariatric surgery increased significantly 3 months after either RYGB or SG (3.58 ± 1.58 vs 3.26 ± 0.7 ng/mL, respectively) and declined at 6 (3.19 ± 1.75 vs 2.8 ± 0.84 ng/mL, respectively) and 12 months (2.6 ± 1.5 vs 2.22 ± 0.49 ng/mL, respectively; p < 0.05 for the effect of time on suPAR levels during the study), whereas those of hsCRP declined consistently after bariatric surgery (3 months: 5.44 ± 3.99 vs 9.47 ± 11.98 mg/dL, respectively; 6 months; 5.39 ± 5.6 vs 10.25 ± 17.22 mg/dL, respectively; and 12 months: 2.23 ± 2.5 vs 3.07 ± 3.63 mg/dL, respectively; p < 0.001 for the effect of time on hsCRP levels during the study). 1-year change in BMI was negatively associated with suPAR levels at 12 months. CONCLUSION: Our findings support an association between obesity and low-grade inflammation. Weight loss following bariatric surgery is associated with a consistent decline in plasma hsCRP, while plasma suPAR levels increase at 3 months and decline by 12 months.

The immediate and long-term impact of physical and/or emotional stress from motor vehicle accidents on circulating stress hormones and adipo-cytokines in children and adolescents.

Motor vehicle accidents (MVA) represent a complex physical and emotional stressor. Consequent short- and/or long-term alterations on the circulating concentrations of stress hormones and adipo-cytokines may have potential health implications. Fifty-nine children and adolescents, aged 7-18 years, were evaluated within 24 h after hospitalization for a MVA, and 1 and 6 months later; 40 children served as controls. We examined longitudinally the effects of physical injury-associated (PI) group vs. emotional-only stress (ES) group on circulating cortisol, catecholamine, interleukin (IL)-6, leptin and adiponectin concentrations. Within 24 h after the accident, serum cortisol concentration was greater than the controls in the PI but not the ES group (p = 0.02), while serum IL-6 concentration was greater in both trauma groups than in the controls (p = 0.004 for PI, p = 0.04 for ES). Adiponectin concentration was lower in the PI than the ES (p = 0.031) and the control (p = 0.019) groups and this was mainly attributed to females. The catecholamine and leptin concentrations were similar in the three groups. At the 1 and 6 month evaluations, cortisol and IL-6 concentrations in both trauma groups became normal. Adiponectin concentration in females, however, remained low 1 and 6 months after the accident (p = 0.03 for month six). In conclusion, circulating IL-6 concentration was influenced equally by the physical and emotional stress shortly after the trauma. Physical but not emotional-only stress lowered the circulating adiponectin concentrations in females and this effect persisted for at least 6 months.

Low free plasma levels of retinol-binding protein 4 in insulin-resistant subjects with polycystic ovary syndrome.

BACKGROUND: It has been shown in animals and in humans that retinol-binding protein 4 (RBP4) production from adipose tissue leads to generalized insulin resistance (IR). A more sensitive marker of circulating RBP4 is free plasma RBP4 expressed by RBP4 to transthyretin (TTR) ratio, since in circulation RBP4 is bound to TTR. AIM: To investigate RBP4 levels in insulin-resistant women with polycystic ovary syndrome (PCOS) and to estimate free plasma RBP4 expressed by RBP4/TTR ratio. SUBJECTS AND METHODS: Thirty-five PCOS subjects were compared with 45 controls matched for age and body mass index (BMI). In each subject, fasting values of glucose, insulin, gonadotropins, estradiol, androgens, C-reactive protein (CRP), RBP4, and TTR were determined. RESULTS: PCOS subjects in comparison to controls were more insulin-resistant [homeostasis model assessment for IR (HOMA-IR): 2.6+/-0.3 vs 1.9+/-0.1, p=0.043], and presented lower RBP4 levels (28.3+/-1.1 vs 32.4+/-1.2 microg/ml, p=0.021) and RBP4/TTR ratio (0.26+/-0.01 vs 0.31+/-0.01, p=0.0014). When RBP4 and RBP4/TTR values where stratified according to BMI status (obese, overweight, and lean subjects), it was noticed that both RBP4 and RBP4/TTR values in lean PCOS were significantly lower than in controls (RBP4: 25.0+/-5.5 vs 34.1+/-9.0 microg/ml, p=0.0063, RBP4/TTR: 0.25+/-0.3 vs 0.35+/-0.1, p=0.016). No correlation was observed between RBP4 and RBP4/TTR with any hormonal or metabolic parameter including BMI. CONCLUSIONS: RBP4 and free plasma RBP4 expressed as RBP4/TTR ratio are statistically and significantly lower in insulin-resistant PCOS subjects in comparison to controls. Therefore, our findings do not confirm a link between IR, neither with RBP4 nor with free plasma RBP4 levels. The significance of these findings remains to be elucidated, since RBP4 might prove to have different actions, like other adipokines, from humans and rodents.

Early markers of renal dysfunction in patients with sickle cell/beta-thalassemia.

Progressive renal failure is one of the main complications in HbS/beta-thalassemia (HbS/beta-thal). Early identification of patients at high risk of developing renal failure is of great importance as it may allow specific measures to delay the progression of renal damage and thus reduce the incidence of end-stage renal failure and mortality. Early predictors of renal impairment in HbS/beta-thal remain to explore. Within this context, we studied 87 compound HbS/beta-thal patients (36 males/51 females; median age 39 years) and 30 healthy controls. In addition to conventional renal biochemistries we measured serum cystatin-C (Cys-C), urine N-acetyl-beta-D-glucosaminidase (NAG) excretion and serum and urinary beta(2)-microglobulin (beta(2)-M). Cystatin-C, NAG and serum beta(2)-M levels were higher in patients than controls. The incidence of patients with high levels of Cys-C, NAG, and beta(2)-M was 32.1, 74.7, and 70.1% respectively, while only 6.8% of patients had increased serum creatinine levels. Cystatin-C and serum beta(2)-M showed a strong correlation with creatinine clearance and age, while NAG positively correlated with proteinuria. An inverse correlation was also shown between hemoglobin and beta(2)-M, NAG, and Cys-C levels. Seven patients with proteinuria received therapy with angiotensin-converting enzyme (ACE) inhibitors. Changes of poteinuria positively correlated with NAG levels. These results indicate that Cys-C is an accurate marker of renal dysfunction, and urinary NAG excretion can be considered as a reliable index of the tubular toxicity, and possible predictor of proteinuria and eventual renal impairment in HbS/beta-thal patients. Furthermore, NAG measurement may be used for monitoring ACE-inhibitors therapy in HbS/beta-thal patients with proteinuria.

Metallothionein expression in human neoplasia.

The metallothionein family is a class of low-molecular-weight, cysteine-rich proteins with high affinity for metal ions. Four major isoforms (metallothionein-1, -2, -3, and -4) have been identified in mammals, involved in many pathophysiological processes, including metal ion homeostasis and detoxification, protection against oxidative damage, cell proliferation and apoptosis, drug and radiotherapy resistance and several aspects of the carcinogenic process. In the present review we examine the expression of metallothionein in different human tumours and its correlation with histopathological variables, tumour cell proliferation or apoptosis, resistance to radiation or chemotherapy, patient survival and prognosis. A variable profile of metallothionein and its isoforms' expression has been observed in different cancer types. Although metallothionein expression has been implicated in carcinogenic evolution, its use as a marker of tumour differentiation, cell proliferation and prognosis predictor remains unclear. Detailed studies focused on the expression of metallothionein isoforms and isotypes in different tumour types could elucidate the role of this group of proteins in the carcinogenic process, delineating its possible clinical significance for the management of patients.

Clinical significance of cytotoxin-associated gene A status of Helicobacter pylori among non-steroidal anti-inflammatory drug users with peptic ulcer bleeding: a multicenter case-control study.

BACKGROUND: The role of Helicobacter pylori infection and especially of the cytotoxin-associated gene A (CagA) product strain in peptic ulcer bleeding among non-steroidal anti-inflammatory drugs (NSAIDs) users remains controversial. METHODS: A case-control study was carried out including 191 consecutive chronic NSAIDs users admitted to hospital because of peptic ulcer bleeding. Peptic ulcer was verified by endoscopy. Controls comprised 196 chronic NSAIDs users without signs of bleeding of similar age and gender to cases. Multivariate regression analysis was performed for further evaluation of the relationship between H. pylori, CagA status and other risk factors. RESULTS: H. pylori infection was present in 121 (63.4%) cases compared with 119 (60.7%) controls (odds ratio (OR) = 1.14, 95% CI, 0.76-1.72). CagA-positive strains were found to be significantly more frequent in cases than in controls (65/106 versus 41/99 P = 0.008). Current smoking (OR = 2.65; 95% CI, 1.14-6.15; P= 0.02), CagA status (OR = 2.28; 95% CI, 1.24-4.19; P = 0.008), dyspepsia (OR = 6.89; 95% CI, 1.84-25.76; P = 0.004) and past history of peptic ulcer disease (OR=3.15; 95% CI, 1.43-6.92; P=0.004) were associated significantly with increased risk of bleeding peptic ulcer. CONCLUSIONS: The results suggest that CagA-positive H. pylori infection is associated with a more than 2-fold increased risk of bleeding peptic ulcer among chronic NSAIDs users.

Metallothionein: a multifunctional protein from toxicity to cancer.

The metallothionein (MT) family is a class of low molecular weight, intracellular and cysteine-rich proteins presenting high affinity for metal ions. Although the members of this family were discovered nearly 40 years ago, their functional significance remains obscure. Four major MT isoforms, MT-1, MT-2, MT-3 and MT-4, have been identified in mammals. MTs are involved in many pathophysiological processes such as metal ion homeostasis and detoxification, protection against oxidative damage, cell proliferation and apoptosis, chemoresistance and radiotherapy resistance. MT isoforms have been shown to be involved in several aspects of the carcinogenic process, cancer development and progression. MT expression has been implicated as a transient response to any form of stress or injury providing cytoprotective action. Although MT participates in the carcinogenic process, its use as a potential marker of tumor differentiation or cell proliferation, or as a predictor of poor prognosis remains unclear. In the present review the involvement of MT in defense mechanisms to toxicity and in carcinogenicity is discussed.

Peroxisome proliferator activated receptor-gamma ligands as potent antineoplastic agents.

The Peroxisome Proliferator Activated Receptors (PPARs) are initially described as molecular targets for compounds inducing peroxisome proliferation. Among the three PPAR subtypes (alpha, beta, gamma), PPAR-gamma acting as a ligand-activated transcription factor, proved to be an important regulator of adipogenic differentiation and glucose homeostasis. Recent data support evidence for participation of PPAR-gamma, upon ligands activation, in the biological mechanisms underlying the carcinogenic evolution. Specific PPAR-gamma ligands affect cancer cells proliferation and differentiation acting as cell cycle modulators, suggesting their use as an important tool for future therapeutic approach in cancer. In this review, the latest knowledge on PPAR-gamma activation and molecular mechanisms of PPAR-gamma ligands mediated anti-tumoral activity are presented. In vitro and in vivo studies concerning the use of PPAR-gamma ligands in different cancer types are also included.

Peroxisome proliferator activated receptor-gamma (PPAR-gamma) ligands and angiogenesis.

The peroxisome proliferator activated receptor (PPAR)- gamma ligands have been initially described as important regulators of adipogenic differentiation and glucose homeostasis. Detailed studies in different tissues pointed to the roles of these ligands in cell proliferation and cancer, establishing their anticancer properties against a wide variety of neoplastic cells. The growth of any solid tumor depends on angiogenesis, as tumor vascularization is a vital process for tumor volume increase and its metastatic potential. Recently, the role of PPAR- gamma ligands as potent angiogenesis modulators in vitro and in vivo, has been referred. This review takes into consideration the latest data concerning the participation of PPAR- gamma ligands in the biological mechanisms underlying angiogenesis inhibition (important in anticancer therapy) and the controversy concerning angiogenesis induction (important in non-neoplastic diseases). As inhibition of angiogenesis represents one of the more promising, new approaches to anticancer therapy, PPAR- gamma ligands in addition to their established role as tumor cell cycle modulators could be implicated in future strategies for cancer treatment.

Expression of metallothionein in lung carcinoma: correlation with histological type and grade.

AIMS: Over-expression of cellular metallothionein occurs frequently in human tumours but the underlying mechanism remains unknown. The aim of this study was to assess metallothionein expression in cases of lung carcinoma and to correlate it with histopathological parameters. METHODS AND RESULTS: Tumour tissue samples from 89 patients with lung carcinoma were immunostained by the streptavidin-biotin-peroxidase technique, using a monoclonal antibody against both metallothionein-1 and -2 isoforms. Positive matallothionein immunostaining was prominent in 44 out of 89 (49%) and negative in 45 out of 89 (51%) cases of lung carcinoma examined. Metallothionein positivity was prominent in 32 out of 43 (74%) cases of squamous cell lung carcinoma, and in 12 out of 35 (34%) cases of adenocarcinoma, while it was negative in all 11 cases of small-cell lung carcinoma examined, presenting a statistically significant difference between the different histological types. The intensity of metallothionein staining revealed a statistically significant difference between the squamous cell and adenocarcinoma cases examined. The pattern and extent of metallothionein staining in tumour cells and the expression of metallothionein in stromal cells were not correlated with histopathological parameters (type and grade) in metallothionein-positive cases of lung carcinoma examined. No association was found between metallothionein expression and lymph node status in the examined cases of lung carcinoma. CONCLUSIONS: Our findings indicate that expression of metallothionein was evident in squamous cell lung carcinoma and adenocarcinoma, but absent in small-cell lung carcinoma, supporting evidence for participation of this protein in the biological mechanisms underlying the carcinogenic evolution in the lung.

Metallothionein and heat shock protein expression during acute liver injury and regeneration in rats.

Metallothioneins (MT) are cytosolic proteins rich in cysteine which play a physiological role in metal ion homeostasis. Heat shock proteins (HSPs) are expressed in various organs in response to different stress stimuli. The purpose of the present study was to examine the intrahepatic distribution of MT and HSP-27, -70 and -90 in two different experimental models of acute liver injury and regeneration, induced by either thioacetamide, or carbon tetrachloride administration in male Wistar rats. Toxicological endpoints and markers of hepatocellular regeneration were assessed at various time points following toxin administration. The enzymatic activities of aspartate and alanine aminotransferases in serum, and histological findings in the liver were used to estimate toxin-induced injury. Tritiated thymidine incorporation into hepatic DNA, liver thymidine kinase activity and hepatocyte mitotic index were used to estimate liver regeneration. MT and HSPs were detected immunohistochemically. At the time of maximum liver injury, moderate MT and intense HSPs expression was prominent in hepatocytes in the vicinity of necrotic areas. At the time of maximum hepatocellular proliferation, intense MT and HSP-90 staining was evident in all hepatocytes, while at the same time, mild HSP-27 and HSP-70 immunoreactivity was noted. Our findings indicate that the differential distribution of MT and HSPs in the liver after toxin-induced injury, in common with the observed pattern of staining, reflect liver proliferating capacity.

Hepatic stimulator substance activity in the liver of thioacetamide-intoxicated rats.

AIMS/BACKGROUND: Hepatic stimulator substance (HSS) is a known hepatic growth factor which appears to be organ-specific but species non-specific. We have recently shown that the administration of HSS enhanced hepatocyte proliferation occurring due to thioacetamide (TAA)-induced liver injury in rats (Theocharis SE, et al., Scand J Gastroenterol 1998; 33: 656-63). In the present study, we examined the activity of the endogenously produced HSS in the liver of TAA administered rats during injury and regeneration. METHODS: TAA at a dose of 300 mg/kg of body weight was injected intraperitoneally in male Wistar rats. The animals were sacrificed at 0, 12, 24, 36, 48, 60 and 72 h after TAA administration. The rate of tritiated thymidine incorporation into hepatic DNA, the enzymatic activity of liver thymidine kinase and the assessment of mitotic index in hepatocytes were used to estimate liver regeneration. HSS extract was obtained from the livers of TAA-treated rats, sacrificed at the above mentioned time points. This HSS extract was injected in 34% partially hepatectomized rats, to assess its activity. The ability of the injected HSS extract to increase hepatocellular proliferation over that normally occurring 24 h following 34% partial hepatectomy was used to express the activity of HSS by determining the above mentioned indices of liver regeneration. RESULTS: The administration of TAA caused severe hepatic injury recognized histopathologically as well as by the increased activities of serum hepatic enzymes aspartate and alanine aminotrasferases. The hepatic injury, which peaked at 24 and 36 h post-TAA treatment (p<0.001), was followed by hepatocyte proliferation, presenting peaks at 48 and 60 h (p<0.001). The activity of the endogenously produced HSS from livers of TAA-treated rats increased at 36 h after TAA administration as well as being highly expressed at 48 and 60 h thus coinciding with the peak of hepatocyte proliferation. At other time points, HSS activity was decreased. CONCLUSIONS: The observed variations of HSS activity in rat liver suggest active participation of this growth factor in hepatocyte replication which follows toxin-induced liver injury as a repair mechanism process.

Putrescine administration reverses cadmium-associated inhibition of liver regeneration.

The liver is of central importance in the metabolism of essential and toxic metals such as cadmium. Cadmium pretreatment suppressed the liver regenerative response to partial hepatectomy, due to the inhibition of the enzymatic activity of thymidine kinase. Exogenous putrescine administration has been reported to stimulate liver regeneration in animal models of acute liver failure. The purpose of this study was to document whether the administration of this polyamine enhances the impaired regenerative capacity of hepatocytes in cadmium-pretreated partially hepatectomized rats. The intraperitoneal administration of putrescine (1 or 10 mg/kg body weight), at the time of surgery and at 4 and 8 hr postoperatively partly restored the suppressed hepatocyte deoxyribonucleic acid (DNA) biosynthesis and thymidine kinase activity in cadmium-pretreated partially hepatectomized rats. Mitotic activity and the percentage of hepatocytes positive for proliferating cell nuclear antigen nuclei were in accordance with the liver proliferative status. Our results showed that exogenous putrescine administration is able to improve diminished liver regeneration after partial hepatectomy in this animal model of acute hepatic injury.

Effect of hepatic stimulator substance administration on tissue regeneration due to thioacetamide-induced liver injury in rats.

BACKGROUND: Hepatic stimulator substance (HSS) is a known hepatic growth factor that appears to be organ-specific but species-nonspecific. In the present study we investigated the effect of HSS administration in a rat model of liver injury and regeneration induced by thioacetamide (TAA) injection. METHODS: TAA (300 mg/kg body weight) was injected intraperitoneally in male Wistar rats (group I). HSS (50 mg protein/kg body weight) was administered intraperitoneally either at 24 h (group II) or at 36 h (group III) after TAA treatment. The animals were killed at different time points after TAA injection, and the rate of tritiated thymidine incorporation into hepatic DNA, the activity of the enzyme thymidine kinase in liver, and the assessment of the mitotic index in hepatocytes were used to estimate liver regeneration. RESULTS: The administration of TAA caused severe hepatic injury recognized histopathologically and by increased activities of the serum hepatic enzymes aspartate and alanine aminotransferases. The hepatic injury, which peaked at 24 h and 36 h after TAA injection, was followed by a regenerative process of hepatocytes which presented peaks after 48 h and 60 h (group I). The regenerative process of hepatocytes remained unaffected when HSS was administered 24 h after the injection of TAA (group II). In the case of HSS administration 36 h after the injection of TAA (group III) the examined indices of hepatocyte proliferation were statistically significantly increased at 48 h (P < 0.001), compared with those observed in group I. CONCLUSIONS: The administration of HSS enhanced the hepatocyte proliferative capacity, induced by TAA treatment, depending on the time of its administration.

Effect of interferon-alpha2b administration on rat liver regeneration after partial hepatectomy.

The purpose of the present study was to delineate the effect of interferon-alpha2b (IFN-alpha2b) administration on the liver regenerative capacity after partial hepatectomy in rats. The administration of IFN-alpha2b simultaneously with partial hepatectomy did not affect hepatic proliferation in a statistically significant manner. When IFN-alpha2b was administered either 2 or 12 hr postoperatively, an inhibition of hepatocyte proliferation was observed 24 hr postoperatively, while at further time intervals up to 48 hr, DNA synthesis remained similar to that observed in the simply partially hepatectomized rats. The enzyme thymidine kinase (TK), has been implicated in the suppression of proliferation in interferon-treated cell cultures. In all IFN-alpha2b-treated groups of rats, alterations of TK activity were observed without being correlated to the liver regenerative status. Additionally, the administration of the polyamine putrescine in partially hepatectomized rats treated at the time of surgery with IFN strongly enhanced TK activity, but did not affect DNA biosynthesis. In the above-mentioned in vivo model of controlled cellular proliferation, the administration of IFN-alpha2b affected the rate of hepatocyte proliferation depending on the time of its administration; this effect was not correlated to the enzymatic activity of TK, as inhibited TK activity is responsible for the suppressed DNA synthesis in in vitro systems.

Granulocyte colony-stimulating factor administration reverses cadmium-associated inhibition of hepatocyte regeneration.

OBJECTIVE: To document whether the administration of granulocyte colony-stimulating factor (G-CSF) enhances the impaired regenerative response of hepatocytes to partial hepatectomy (PH), in cadmium-pretreated partially hepatectomized rats. MATERIALS AND METHODS: Rats were injected intraperioneally with 2.5 mg CdCl2/kg body weight, 24h before PH. G-CSF (1500 or 150 micrograms/kg body weight) or saline was administered intraperitoneally in cadmium-pretreated partially hepatectomized rats at the same time as PH. The liver regenerative process was estimated 24h after PH. [3H] thymidine incorporation into liver DNA, liver thymidine kinase (TK) activity, mitotic index and proliferating cell nuclear antigen (PCNA) immunostaining were used as indices of hepatocyte proliferation. RESULTS: G-CSF administration in cadmium-pretreated partially hepatectomized rats restored the suppressed DNA biosynthesis and TK activity (P < 0.001), to levels similar to those found in rats that were partially hepatectomized only. The mitotic index and the percentage of PCNA positive nuclei in hepatocytes were also enhanced in G-CSF administered cadmium-pretreated partially hepatectomized groups of rats. CONCLUSION: The administration of G-CSF triggers events that restore the impaired liver regeneration in this model of reduced hepatocyte proliferation.

Hepatic stimulator substance administration enhances regenerative capacity of hepatocytes in cadmium-pretreated partially hepatectomized rats.

The liver is of central importance in the metabolism of essential and toxic metals such as cadmium (Cd). Cd pretreatment suppressed the regenerative capacity of hepatocytes, which normally occurs 24 hr after partial hepatectomy, due to the inhibition of the activity of the enzyme thymidine kinase. The effect of hepatic stimulator substance (HSS) administration (10, 20, and 40 mg protein/kg body weight) on hepatocyte proliferation was investigated in Cd-pretreated partially hepatectomized rats. HSS administration partly restored the suppressed hepatocyte DNA biosynthesis in Cd-pretreated partially hepatectomized rats. The hepatocyte mitotic activity and the percentage of proliferating cell nuclear antigen-positive nuclei were in accordance with the liver proliferative status. The administration of HSS did not affect in a statistically significant manner the activity of the enzyme thymidine kinase in Cd-pretreated partially hepatectomized rats. It is suggested that the administration of HSS ameliorates the diminished hepatocyte regenerative response to partial hepatectomy in this model of acute liver injury, due to Cd intoxication.

Effect of cadmium on liver regeneration after partial hepatectomy in rats.

Cadmium is a nonabundant element that is widely distributed throughout the biosphere and its toxic effects are becoming potentially more serious due to industrialization. It has been reported that cadmium might interact with nucleic acid biosynthesis. In this study we examined the effect of cadmium administration, either 24 hr before or simultaneously to partial hepatectomy, on the liver regenerative process in rats, at different time intervals. The rate of DNA synthesis was suppressed markedly in the cadmium pretreated group and the first peak of liver regeneration was delayed, compared to the simply partially hepatectomized one. The administration of cadmium simultaneously to partial hepatectomy, caused a marked decrease of the rate of DNA biosynthesis, compared to the pretreatment. The rate-determining enzyme thymidine kinase was suppressed in the liver of both cadmium-treated groups. Biochemical parameters and histological findings were also coestimated. The above data suggest that either pre- or simultaneous administration of cadmium, suppressed the liver regenerative process, probably due to the inhibition of thymidine kinase.

Thymidine kinase activity in liver and serum of rats after cadmium administration.

Intraperitoneal administration of a cadmium (Cd) salt at concentrations of 2.5 and 4.0 mg CdCl2/kg of body wt., caused time-dependent severe liver injury, in Quinster rats, more intense at the higher administered dose. Thymidine kinase, the key enzyme of the salvage pathway of DNA biosynthesis, was strongly affected in liver tissue and serum of cadmium-intoxicated rats. Lower thymidine kinase activity was observed both in liver and serum of rats treated with the higher dose of cadmium, in which the maximal liver injury appeared.

Cadmium-induced hepatotoxicity in three different rat strains.

Cadmium (Cd) is a highly toxic element able to induce acute liver injury in rats after intraperitoneal administration. The dose-dependent Cd-induced hepatotoxicity was examined in three different rat strains. A difference in hepatotoxicity was observed in the three rat strains, determined by the examination of serum enzymes' activities and other biochemical parameters, all markedly altered after Cd intoxication. The histological findings came to confirm the variations of the above-mentioned parameters. It is concluded that the administration of this toxic agent caused different toxicity in the three rat strains examined, indicating a more intense damage in Wistar than in Quinster and Lewis rats.