OC-07 - Decoding risk for thromboembolic events in lymphoma patients.

INTRODUCTION: There are few prediction tools for estimating the risk of thrombosis but they are based on studies performed on hospitalized medical patients without cancer or on hospitalized neutropenic cancer patients without special consideration to lymphoma patients. AIM: Aim of our study was to determine incidence of thromboembolic (TE) events in patients with non Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL) and chronic lymphocytic leukemia (CLL)/ small lymphocytic lymphoma (SLL) who were hospitalized to the lymphoma department in the Clinic of hematology, Clinical Center Serbia, Belgrade and Clinic of hematology, Clinical Center Kragujevac. Also, we assessed 2 predictive models (Padua and Khorana score) and create new model for the identification of lymphoma patients at risk for thromboembolism. MATERIALS AND METHODS: We reviewed all medical records of patients with with NHL, HL and CLL/SLL diagnosed and treated at two previously mentioned institution between January 2006 and December 2014. RESULTS: The study population included 1820 eligible lymphoma patients. Of all the patients included in the study, 99 (5.4%) developed at least one TE during a follow-up period of 3 months from the end of therapy. In the final multivariate analysis, the following variables were independently associated with risk of TE: previous VTE and/or arterial events, reduced mobility (ECOG 2-4), obesity (BMI >30 kg/m(2)), extranodal localization, mediastinum involvement, development of neutropenia during therapy and hemoglobin level less than 100g/L. Subsequently, we assigned points for the risk model based on the regression coefficients obtained from the final model and developed Thrombosis Lymphoma (ThroLy) score consisting of all significant variables from the multivariate analysis. The Throly score was arrived at by assigning 2 points for all parameters with an OR >5 in multivariate regression analyses (e.g., previous VTE and arterial events, mediastinum involvement, and BMI) and 1 point for rest all other significant variables. Finally, population were divided into 3 risk categories for TE based on the score from the risk model: low (score 0-1), intermediate (score 2-3) and high (score >3). High risk score had a positive predictive value (probability of TE in those designated high risk) of 65.2%. CONCLUSIONS: Significance of our investigation is development of score that help phisicians to recruit lymphoma patients at risk for development of thromboembolic complications. Also, we can say that our score is dynamic allowing us to change approach during different phase of therapy and is not limited to outpatient settings or with some complicated laboratory analysis.

Effect of streptozotocin-induced diabetes on glycogen resynthesis in fasted rats post-high-intensity exercise.

It has recently been shown that food intake is not essential for the resynthesis of the stores of muscle glycogen in fasted animals recovering from high-intensity exercise. Because the effect of diabetes on this process has never been examined before, we undertook to explore this issue. To this end, groups of rats were treated with streptozotocin (60 mg/kg body mass ip) to induce mild diabetes. After 11 days, each animal was fasted for 24 h before swimming with a lead weight equivalent to 9% body mass attached to the tail. After exercise, the rate and the extent of glycogen repletion in muscles were not affected by diabetes, irrespective of muscle fiber composition. Consistent with these findings, the effect of exercise on the phosphorylation state of glycogen synthase in muscles was only minimally affected by diabetes. In contrast to its effects on nondiabetic animals, exercise in fasted diabetic rats was accompanied by a marked fall in hepatic glycogen levels, which, surprisingly, increased to preexercise levels during recovery despite the absence of food intake.

Glycogen repletion following burst activity: a carbohydrate-sparing mechanism in animals adapted to arid environments?

The Western chestnut mouse (Pseudomys nanus ferculinus) is one of several native rodent species adapted to the arid environments of Australia. Since these environments are often associated with a paucity in dietary carbohydrate, the problem arises as to the mechanism whereby these rodents replete their stores of muscle glycogen when recovering from high intensity physical activity. This is an important issue since the maintenance of adequate stores of muscle glycogen is crucial to support the energy demands associated with 'flight or fight' responses. Whilst it is known that food ingestion post-exercise is required for the total repletion of muscle glycogen in rats and humans, our findings indicate that the Western chestnut mouse has the impressive capacity to replete completely its stores of muscle glycogen, even in the absence of food intake. Indeed during recovery from burst activity which results in the massive breakdown of the stores of muscle glycogen, the levels of glycogen return back to pre-exercise levels within only 50 minutes despite the absence of food intake. This capacity is important in the broader context of nutritional adaptation to arid/seasonally-arid regions since it allows muscles to replete their fuel stores even when food is not available. How common is this strategy among desert-adapted mammal species is a question yet to be answered.

Regulation of glycogen synthase and phosphorylase during recovery from high-intensity exercise in the rat.

The aim of this study was to determine the role of the phosphorylation state of glycogen synthase and glycogen phosphorylase in the regulation of muscle glycogen repletion in fasted animals recovering from high-intensity exercise. Groups of rats were swum to exhaustion and allowed to recover for up to 120 min without access to food. Swimming to exhaustion caused substantial glycogen breakdown and lactate accumulation in the red, white and mixed gastrocnemius muscles, whereas the glycogen content in the soleus muscle remained stable. During the first 40 min of recovery, significant repletion of glycogen occurred in all muscles examined except the soleus muscle. At the onset of recovery, the activity ratios and fractional velocities of glycogen synthase in the red, white and mixed gastrocnemius muscles were higher than basal, but returned to pre-exercise levels within 20 min after exercise. In contrast, after exercise the activity ratios of glycogen phosphorylase in the same muscles were lower than basal, and increased to pre-exercise levels within 20 min. This pattern of changes in glycogen synthase and phosphorylase activities, never reported before, suggests that the integrated regulation of the phosphorylation state of both glycogen synthase and phosphorylase might be involved in the control of glycogen deposition after high-intensity exercise.

Muscle glycogen repletion from endogenous carbon sources during recovery from high intensity exercise in the fasted rat.

During recovery from high intensity exercise, substantial and rapid muscle glycogen repletion from endogenous carbon sources is reported in a variety of vertebrate species, the rat being the only reported exception. The major aim of this study was to re-examine the process of glycogen repletion during recovery from high intensity exercise in the rat. In response to 3 min of vigorous swimming, muscle glycogen concentrations decrease markedly from initial levels of 20.2 +/- 1.5 and 21.2 +/- 0.9 mumol g-1 to 6.4 +/- 1.1 and 7.9 +/- 1.4 mumol g-1 in the tibialis anterior and plantaris muscles respectively. The equivalent of 58% of the glycogen carbons mobilized during exercise by the plantaris and 73% of that mobilized by the tibialis anterior muscle is repleted within 1 h following exercise. Using the hepatectomized rat as experimental model, a secondary aim of the study was to evaluate whether the liver is essential for the repletion of muscle glycogen. Although the absence of significant differences in the magnitude of post-exercise muscle glycogen repletion between sham-operated and hepatectomized rats suggests that the resynthesis of muscle glycogen can take place in the absence of hepatic gluconeogenesis, the present study identifies several limitations in the use of acute hepatectomy. Overall, the present study indicates that, in contrast to published views, the rat resembles other vertebrates in that it can support extensive muscle glycogen repletion from endogenous carbon sources during the recovery phase following high intensity exercise.

Ethanol acutely impairs glycogen repletion in skeletal muscle following high intensity short duration exercise in the rat.

Ethanol is recognized to affect adversely carbohydrate metabolism in skeletal muscle. This paper seeks to establish whether ethanol acutely impairs glycogen repletion during recovery from high intensity short duration exercise in the rat. High intensity exercise caused the massive mobilization of glycogen stores in muscles rich in type IIa and IIb fibres and marked increases in plasma and muscle lactate levels. During the 30-minute recovery period, there was substantial glycogen repletion in these muscles in both the ethanol-treated and control rats. Ethanol, however, was associated with reduced glycogen resynthesis in both the tibialis anterior (by 22%) and red gastrocnemius (by 31%) muscles but not in the white gastrocnemius muscle. This reduction in post-exercise glycogen deposition was accompanied by decreased lactate disposal and elevated plasma glucose levels. These effects of ethanol on glycogen repletion may involve interactions with hepatic gluconeogenesis, glucose uptake and utilization in muscle, muscle glycogen synthesis and lactate glyconeogenesis. The ethanol-mediated impairment in post-exercise glycogen repletion may have important implications for the pathogenesis of chronic alcoholic skeletal myopathy.