The national programme of expanded access to antiretroviral therapy in the South African public health sector has resulted in hundreds of thousands of South Africans being subjected to prolonged therapy with the risk of adverse drug effects. Among the most common adverse effects are metabolic disorders one of which is mitochondrial toxicity. Mitochondrial toxicity may manifest as hyperlactatemia. The study was designed to determine the frequency with which hyperlactatemia occurs in HIV – infected adults on long-term antiretroviral therapy (ART). The objective was to determine the proportion of patients with blood lactate levels that exceed a predetermined cut-off level and to attempt to relate hyperlactatemia to a set of factors namely, gender, age, obesity, symptoms, type of ART regime and duration of ART use. The study was conducted at an ART clinic in the provincial state hospital of Bongani in the town of Welkom in Free State. The target population was male and female adult patients (18 years and above) on ART for a duration of 1 year or longer. Participants were selected by a random sampling of hospital case file numbers using random table numbers. The patients answered a set of 7 questions on symptoms, underwent weight and height measurements before having blood drawn for lactate assays Blood specimens for lactate assays were processed at the local National Health laboratory.

Malgré le manque d’études sur ce sujet, le cancer est considéré comme une des principales causes d’hyperlactatémie de type B chez le chien. Les cellules malignes ont une production accrue de lactates secondaire à une glycolyse aérobie accrue, via l’effet Warburg. Les mécanismes ne sont pas encore clairement établis mais certains auteurs suggèrent que le cancer pourrait causer une hyperlactatémie via l’effet Warburg. Cette étude a pour objectif de déterminer si les tumeurs malignes peuvent être associées à une hyperlactatémie cliniquement significative (≥2,5 mmol/L) chez le chien. Trente-sept chiens atteints de tumeurs malignes ont été recrutés (22 atteints de tumeurs hématopoïétiques et 15 de tumeurs non hématopoïétiques). Le diagnostic était confirmé par analyse histologique, ou cytologique en cas de lymphome. Les autres causes possibles d’hyperlactatémie étaient écartées puis la mesure des lactates sanguins était réalisée sur sang veineux jugulaire immédiatement analysé avec le LactatePro®. Aucun chien n’était hyperlactatémique. La concentration moyenne en lactates sanguins était de 1,09 mmol/L. La concentration moyenne en lactates sanguins pour les chiens atteints de tumeurs non hématopoïétiques et hématopoïétiques était respectivement de 0,95 mmol/L et de 1,19 mmol/L. Les chiens atteints de lymphome (n=18) avaient une concentration moyenne en lactates sanguins de 1,15 mmol/L. Les tumeurs malignes ne sont pas associées à une hyperlactatémie de type B cliniquement significative chez le chien. L’hyperlactatémie tumorale est donc une complication rare chez le chien. Son diagnostic devrait conduire à une investigation minutieuse des autres causes d’hyperlactatémie. / Cancer is considered a cause of type B hyperlactatemia in dogs. However, studies evaluating cancer as a cause of clinically relevant type B hyperlactatemia (≥2.5 mmol/L) are lacking. It is well accepted that cancer cells have a higher lactate production due to increased aerobic glycolysis, known as the Warburg effect. The mechanisms through which aerobic glycolysis occurs are not well elucidated but it has been suggested that neoplasia may cause type B hyperlactatemia via this process. The aim of this study is to determine if canine malignant tumors could be associated with a clinically relevant type B hyperlactatemia (≥ 2.5 mmol/L). Thirty-seven dogs with malignant tumors were included: 22 with hematopoietic and 15 with solid tumors. Histology was used to confirm the diagnosis (cytology was considered appropriate for lymphoma). Confounding factors associated with hyperlactatemia were excluded. Lactate measurements were obtained from a free flow jugular whole blood sample and immediately analyzed using the LactatePro®. All dogs had lactate values less than 2.5 mmol/L. The mean blood lactate concentration was 1.09 mmol/L. The mean blood lactate concentration for solid and hematopoietic tumor was 0.95 mmol/L and 1.19 mmol/L respectively. Dogs with lymphoma (n = 18) had a mean blood lactate concentration of 1.15 mmol/L. Malignant tumors were not considered a cause of clinically relevant type B hyperlactatemia. Therefore, cancer related type B hyperlactatemia in dogs with cancer is uncommon and its diagnosis should prompt careful investigation for causes other than cancer.

Malgré le manque d’études sur ce sujet, le cancer est considéré comme une des principales causes d’hyperlactatémie de type B chez le chien. Les cellules malignes ont une production accrue de lactates secondaire à une glycolyse aérobie accrue, via l’effet Warburg. Les mécanismes ne sont pas encore clairement établis mais certains auteurs suggèrent que le cancer pourrait causer une hyperlactatémie via l’effet Warburg. Cette étude a pour objectif de déterminer si les tumeurs malignes peuvent être associées à une hyperlactatémie cliniquement significative (≥2,5 mmol/L) chez le chien. Trente-sept chiens atteints de tumeurs malignes ont été recrutés (22 atteints de tumeurs hématopoïétiques et 15 de tumeurs non hématopoïétiques). Le diagnostic était confirmé par analyse histologique, ou cytologique en cas de lymphome. Les autres causes possibles d’hyperlactatémie étaient écartées puis la mesure des lactates sanguins était réalisée sur sang veineux jugulaire immédiatement analysé avec le LactatePro®. Aucun chien n’était hyperlactatémique. La concentration moyenne en lactates sanguins était de 1,09 mmol/L. La concentration moyenne en lactates sanguins pour les chiens atteints de tumeurs non hématopoïétiques et hématopoïétiques était respectivement de 0,95 mmol/L et de 1,19 mmol/L. Les chiens atteints de lymphome (n=18) avaient une concentration moyenne en lactates sanguins de 1,15 mmol/L. Les tumeurs malignes ne sont pas associées à une hyperlactatémie de type B cliniquement significative chez le chien. L’hyperlactatémie tumorale est donc une complication rare chez le chien. Son diagnostic devrait conduire à une investigation minutieuse des autres causes d’hyperlactatémie. / Cancer is considered a cause of type B hyperlactatemia in dogs. However, studies evaluating cancer as a cause of clinically relevant type B hyperlactatemia (≥2.5 mmol/L) are lacking. It is well accepted that cancer cells have a higher lactate production due to increased aerobic glycolysis, known as the Warburg effect. The mechanisms through which aerobic glycolysis occurs are not well elucidated but it has been suggested that neoplasia may cause type B hyperlactatemia via this process. The aim of this study is to determine if canine malignant tumors could be associated with a clinically relevant type B hyperlactatemia (≥ 2.5 mmol/L). Thirty-seven dogs with malignant tumors were included: 22 with hematopoietic and 15 with solid tumors. Histology was used to confirm the diagnosis (cytology was considered appropriate for lymphoma). Confounding factors associated with hyperlactatemia were excluded. Lactate measurements were obtained from a free flow jugular whole blood sample and immediately analyzed using the LactatePro®. All dogs had lactate values less than 2.5 mmol/L. The mean blood lactate concentration was 1.09 mmol/L. The mean blood lactate concentration for solid and hematopoietic tumor was 0.95 mmol/L and 1.19 mmol/L respectively. Dogs with lymphoma (n = 18) had a mean blood lactate concentration of 1.15 mmol/L. Malignant tumors were not considered a cause of clinically relevant type B hyperlactatemia. Therefore, cancer related type B hyperlactatemia in dogs with cancer is uncommon and its diagnosis should prompt careful investigation for causes other than cancer.