Numerous disorders cause, are caused by, or are worsened by some form of disturbance in physiologic pressure. Researchers look at these pressure changes in animal models to better understand the disorder and evaluate treatment options. DSI is the leader in blood pressure telemetry, but did you know DSI’s pressure implants can be used for so much more than blood pressure and hypertension research? The following is an overview of novel applications for pressure measurements using DSI telemetry. For additional information on how researchers integrate DSI solutions in their studies, see the list of publications at the end.
Beyond Blood Pressure: Pressure Measurements
Tumor pressure
Increased solid tumor pressure has been recognized as a barrier to effective cancer treatment leading to poor prognosis in both humans and animals. There are two types of pressure which can be disrupted by the existence of a tumor: interstitial fluid and bone pressure, and both can be measured with DSI telemetry.
Researchers monitoring tumor interstitial fluid pressure (IFP) in vivo are able to observe a correlation between tumor growth, increased IFP and a decrease in treatment response. This data offers researchers earlier indications as to whether a compound or treatment is effecting solid tumor progression.
Bone tissue is one of the most common sites of metastasis and occurs when cancer cells from a primary tumor, typically breast, lung or prostate, migrate to the bone through the blood stream or lymphatic system. Secondary bone cancer, caused by metastasis, is more common than primary. Currently, there is no cure for bone metastasis, only treatment to reduce its progression. By measuring tumor pressure within the bone, researchers have found increased pressure caused by tumor growth promotes osteocyte secretion, leading to increased metastasis. Methods to obtain bone pressure include the insertion of a DSI pressure sensor inside the intramedullary cavity of the bone.
Intracranial pressure (ICP)
Changes in ICP can result from a number of disorders including traumatic brain injury, infection, tumor, stroke, aneurysm, epilepsy, seizure, accumulation of spinal fluid, hypoxemia, and meningitis.1 If left untreated, increases in ICP can result in brain damage, coma, or death.1 DSI’s pressure telemetry allows researchers to measure ICP in animal models of these disorders to better understand them and evaluate treatment options.
Intraocular pressure (IOP)
Accurate measurements of IOP provide valuable information for glaucoma research. DSI telemetry offers several benefits in comparison to other methods with its ability to continuously measure IOP in conscious, freely moving animals with open or closed eyelids. Artifacts caused by restraint, local anesthesia, and human investigator intervention are eliminated. In addition, the animals are unaware that they are being monitored and can stay in their normal environment during data collection.
A case study is available on our website to learn more about measuring IOP in animal models. Note, the PA-C40, small animal pressure sensing implant, used in this case study has been replaced by the PhysioTel™ HD-S10. This newer implant offers additional value to researchers. You can learn about these benefits on our small animal telemetry webpage.
Pleural pressure
In respiratory physiology, lung compliance and resistance to lung airflow are used as critical measures of lung function. In order to achieve this, both respiratory flow and thoracic pressure measurements are required. DSI’s pressure telemetry allows researchers to measure pleural pressure. Poor lung function could signify a number of disorders including asthma, chronic obstructive pulmonary disorder (COPD), lung fibrosis, and more.
A case study is available on our website if you are interested in learning about the surgical procedure and implant placement to measure pleural pressure. Note, as stated above, the PA-C40 implant used in this case study has been replaced by the HD-S10.
Bladder pressure
Measurements of bladder pressure are useful for kidney and other urogenital diseases. DSI’s Ponemah software offers a cystometry analysis module to identify voiding events which may be used when studying a variety of diseases which affect bladder control.
A case study is available on DSI’s website if you are interested in learning more about measuring bladder pressure (alone or simultaneously with blood pressure) with telemetry. Note, the D70-PCP, a large animal implant capable of simultaneously collecting two pressure signals and one biopotential, used in this case study has been replaced by the PhysioTel™ Digital L21. This implant offers researchers additional value which can be found on our large animal telemetry webpage. For updates on surgical procedures with the new implant, please complete the form at the end of this post. The Dataquest ART software used in this study has also been replaced by Ponemah, offering the researcher improved analysis capabilities.
Beyond Cardiovascular Disease: Applications for Blood Pressure Measurements
Researchers are increasingly combining applications as their interest in understanding how conditions are related to one another has grown significantly. Cardiovascular endpoints, like blood pressure, assist in combination studies related to metabolic disease, sleep apnea, stress or anxiety, and more. The following is a brief overview of how blood pressure measurements can play a role in each of these disorders. To learn more, peruse the publications cited below.
Metabolic Disease
Patients suffering from metabolic disease or obesity commonly develop hypertension as well. Although the link is not fully understood, a great deal of research currently aims to shed light on this relationship. While there are a broad range of interests in the topic, a few types of studies include looking to understand which disease comes first, how one causes the other, and the effects of administering additional insulin on blood pressure levels. In large animals, it is now possible to measure blood glucose and blood pressure continuously and simultaneously with DSI telemetry, offering an ideal solution for these types of studies.
Sleep Apnea
Sleep apnea is known to cause secondary hypertension. When patients stop breathing during sleep, they experience surges in blood pressure.2 These surges cause mean blood pressure to remain elevated throughout the night and over time can lead to chronic elevation.2 To study this relationship, researchers often measure cardiovascular endpoints, such as blood pressure, in addition to or simultaneously with respiratory endpoints. DSI pressure telemetry can be combined with Buxco respiratory plethysmography chambers to provide a full solution for those interested in measuring the two simultaneously. In large animal models, researchers can also obtain pressure and respiratory measurements, a biopotential (typically EEG, ECG, or EMG), temperature, and activity using a single implant.
Stress and Anxiety
High blood pressure and a fast heart rate are strong indicators of stress. Researchers will often use these measurements to create models of stress and anxiety or to look at the effects of certain conditions on stress levels. In some models of depression or anxiety, researchers may be interested in measuring EEG, ECG, or EMG with blood pressure. DSI telemetry provides the flexibility to measure these endpoints with core body temperature and activity.
Contact us today to learn more about solutions to serve your research!
Applicable Publications Citing Use of DSI Solutions
Tumor Pressure
- Sabelstrom H, Iikhanizadeh S, Miroshnikova YA, Frantz A, Zhu W, Idilli A, Quigley D, Fenster T, Yuan E, Saxena S, Mouw JK, Burdick JA, Magnitsky S, Berger MS, Arosio D, Sun D, Weaver VM, Weiss WA, Persson AI. (2017). “Exth-23. Antisecretory Factor-Mediated Lowering Of Interstitial Fluid Pressure Produces Anti-Tumor Activity In Glioblastoma”. Neuro-Oncology. 19(Suppl_6); Vi77-Vi77. https://dx.doi.org/10.1093%2Fneuonc%2Fnox168.317
- Sottnik JL, Dai J, Zhang H, Campbell B, Keller ET. (2015). “Tumor-Induced Pressure in the Bone Microenvironment Causes Osteocytes to Promote the Growth of Prostate Cancer Bone Metastases”. Cancer Research. 75(11); 2151-2158. https://doi.org/10.1158/0008-5472.CAN-14-2493
Intracranial Pressure
Pleural Pressure
- Sladena L, Matheson M, Norton K, Milne A. (2018). “Regulatory respiratory data refinement with reduced animal usage”. Journal of Pharmacological and Toxicological Methods. 93; 69-74. https://doi.org/10.1016/j.vascn.2018.03.005
- Murphy DJ, Renninger JP, Gossett KA. (1998). “A novel method for chronic measurement of pleural pressure in conscious rats”. Journal of Pharmacological and Toxicological Methods. 39;137-141. https://doi.org/10.1016/S1056-8719(98)00008-2
Intraocular Pressure
- Todani A, Behlau I, Fava MA, Cade F, Cherfan DG, Zakka, FR, Jakobiec FA, Gao Y, Dohlman CH, Melki SA. (2011). “Intraocular Pressure Measurement by Radio Wave Telemetry”. Investigative Ophthalmology & Visual Science. 52;9573-9580. https://iovs.arvojournals.org/article.aspx?articleid=2187042
- McLaren JW, Brubaker RF, FitzSimon JS. (1996). “Continuous Measurement of Intraocular Pressure in Rabbits by Telemetry”. Invest. Ophthalmol Vis Sci. 37; 966-975. https://iovs.arvojournals.org/article.aspx?articleid=2180624
- Schnell CR, Debon C, Pericott CL. (1996). “Measurement of Intraocular Pressure by Telemetry in Conscious, Unrestrained Rabbits”. Invest. Ophthalmol Vis Sci. 37; 958-965. https://iovs.arvojournals.org/article.aspx?articleid=2180614
Bladder Pressure
Metabolic Disease and Blood Pressure
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Nizar JM, Dong W, McClellan RB, Labarca M, Zhou Y, Wong J, Goens DG, Zhao M, Velarde N, Bernstein D, Pellizzon M, Satlin LM, Bhall V. (2016). “Na+-sensitive elevation in blood pressure is ENaC independent in diet-induced obesity and insulin resistance”. Renal Physiology. https://doi.org/10.1152/ajprenal.00265.2015
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Fluitt MB, Rizvi S, Li L, Alunan A, Lee H, Tiwari S, Ecelbarger CM. (2018). “Chronic Insulin Infusion Down-Regulates Circulating and Urinary Nitric Oxide (NO) Levels Despite Molecular Changes in the Kidney Predicting Greater Endothelial NO Synthase Activity in Mice”. International Journal of Molecular Sciences. 19(10);2880. https://dx.doi.org/10.3390%2Fijms19102880
Sleep Apnea and Blood Pressure
- Jameson H, Bateman R, Byrne P, Dyavanapalli J, Wang X, Jain V, Mendelowitz D. (2016). “Oxytocin neuron activation prevents hypertension that occurs with chronic intermittent hypoxia/hypercapnia in rats”. Cardiovascular Neurohormonal Regulation. 310:11, H1549-H1557. https://doi.org/10.1152/ajpheart.00808.2015
- Burke PGR, Kanbar R, Viar KE, Stornetta RL, Guyenet PG. (2015). “Selective optogenetic stimulation of the retrotrapezoid nucleus in sleeping rats activates breathing without changing blood pressure or causing arousal or sighs”. Journal of Applied Physiology. 118(12); 1491-1501. https://doi.org/10.1152/japplphysiol.00164.2015
Stress/Anxiety and Blood Pressure
- Wang L, Hiller H, Smith JA, de Kloet AD, Krause EG. (2016). “Angiotensin type 1a receptors in the paraventricular nucleus of the hypothalamus control cardiovascular reactivity and anxiety-like behavior in male mice”. Physiological Genomics. 48(9); 667-676. https://doi.org/10.1152/physiolgenomics.00029.2016
- Swiercz AP, Seligowski AV, Park J, Marvar PJ. (2018). “Extinction of Fear Memory Attenuates Conditioned Cardiovascular Fear Reactivity”. Frontiers in Behavioral Neuroscience. 12(276). https://dx.doi.org/10.3389%2Ffnbeh.2018.00276
References
1Carey E. (2018). “Increased Intracranial Pressure”. Healthline. https://www.healthline.com/health/increased-intracranial-pressure#causes-and-risk-factors
2Dopp JM, Reichmuth KJ, Morgan BJ. (2007). “Obstructive sleep apnea and hypertension: mechanisms, evaluation, and management”. Current Hypertension Reports. 9(6); 529-34. https://www.ncbi.nlm.nih.gov/pubmed/18367017