Carotid body tumor imaging: MRI, ultrasound, and elastography with surgical management.

A carotid body tumor is an uncommon tumor that develops from the carotid body. Carotid body tumor, also called paraganglioma, is often benign in nature and mostly found in the neck. They make up 0.5% of all body tumors and resemble glomus jugulare, glomus tympanicum, and pheochromocytoma, which are paragangliomas of the body. We present a case of a 22-year-old male patient who presented to the medical outpatient department with complaints of swelling in the left carotid triangle for 1 month. The patient had hoarseness of voice with odynophagia and dysphagia. We found out the diagnosis of carotid body tumor when the patient came for ultrasound, and the diagnosis was later confirmed on magnetic resonance imaging. The gold standard treatment for carotid body tumors is surgery. The surgical categorization by Shamblin et al. marks a turning point in the evaluation of these tumors' resectability and is still used to predict vascular morbidity, and according to it, our patient later underwent sub adventitial tumor excision.

ALTERED CONTROL OF BREATHING IN A RAT MODEL OF ALLERGIC LOWER AIRWAY INFLAMMATION.

Obstructive sleep apnea (OSA) is highly prevalent in patients with asthma. Asthma, dose-dependently to its duration, promotes incident OSA, suggesting that asthma plays a role in OSA pathogenesis. We hypothesized that asthma-related inflammation alters breathing control mechanisms, specifically the carotid chemoreflex. Accordingly, we measured hypoxic ventilatory responses (HRV) in awake, unrestrained, ovalbumin (OVA)-sensitized Brown Norway rats and compared them with responses in sham-sensitized (SALINE) controls. To differentiate the role of allergic inflammation from bronchoconstriction, we repeated HVR after administration of formoterol, a long-acting bronchodilator. Blood and bronchoalveolar lavage (BAL) fluid were collected for quantification of inflammatory cytokines. The rise in ventilatory equivalent for O2 evoked by acute exposure to hypoxia was augmented following sensitization by OVA, whereas it remained stable after SALINE. This augmentation was driven by increased breathing frequency with no change in tidal volume. Tachypneic hyperventilation in normoxia was also observed with OVA. Neither the increased HVR nor excessive normoxic ventilation was affected by formoterol, suggesting that they were not secondary to lung mechanical constraints. Higher levels of inflammatory cytokines were observed in BAL fluid and serum of OVA vs. SALINE. In OVA, serum interleukin-5 correlated with change (baseline to post-sensitization) in ventilatory response to severe hypoxia (FIO2, 0.09). These observations are consistent with inflammation-induced enhancement of carotid chemoreflex function, i.e. increased controller gain, and they suggest a possible role for asthma-related allergic inflammation in the ventilatory instability known to promote upper airway collapse and sleep apnea in humans.

Malignant peripheral nerve sheath tumor mimicking carotid body tumor, a rare case report and review of literature.

INTRODUCTION AND IMPORTANCE: Malignant Peripheral Nerve Sheath Tumor (MPNST) is a rare type of soft tissue sarcoma. It is an aggressive tumor with high rates of local recurrence and distant metastasis. MPNST rarely occurs in the neck. We present a case of cervical MPNST manifesting as Carotid Body Tumor (CBT). CASE PRESENTATION: A 67-year-old man presented with a neck mass. The mass was rapidly enlarging and imaging studies favored CBT. A previous attempt at surgical resection failed, and the compressive symptoms were progressive during recent weeks. After multidisciplinary discussion, the tumor was resected and pathological evaluation confirmed the diagnosis of MPNST. Post-operative metastatic work-up showed lung metastasis, and the patient died approximately one year after surgery. CLINICAL DISCUSSION: Cervical MPNST is rare, and surgery is the mainstay of its treatment. Pre-operative tissue diagnosis is recommended when possible, and immunohistochemical staining is necessary for prompt diagnosis. Adjuvant therapy may be helpful in metastatic cases or incomplete resection. Nevertheless, local recurrence and distant metastasis especially to the lungs are common, as in our case. CONCLUSION: MPNST is one of the potential causes of cervical masses and considering its invasive behavior, surgical resection is recommended as soon as the diagnosis is made.

Head and neck paragangliomas: Recent advances in translational and clinical research and guidelines for patient care.

Head and neck paragangliomas (HNPGLs), rare neuroendocrine tumors that mainly arise from parasympathetic ganglia along the cranial nerves, are challenging due to anatomic origin, tendency to aggressive neurovascular and skull base infiltration, unpredictable metastatic potential, radio-chemoresistance, and risk of multiplicity. Symptoms range from mild to life threatening depending on location/size, but rarely relate to catecholamine excess. Risk factors include female sex and pathogenic germline variants in genes affecting hypoxia signaling (foremost succinate dehydrogenase genes). Diagnostic work-up relies on imaging, measurements of plasma free metanephrines/methoxytyramine, genetic testing, and pathology/immunohistochemistry. Management is tailored to patient/tumor characteristics and encompasses wait-scan, upfront surgery, debulking surgery, and radiotherapy. Presurgical embolization is recommended, except for small tympanic and tympanomasoid tumors. Presurgical stenting is required for internal carotid artery involvement, and two-stage surgery for intradural extension. Current treatments for metastatic/inoperable HNPGL are non-curative, and long-term follow-up should be recommended for all patients to monitor local recurrence and new tumors.

Expression of the cellular prion protein by mast cells in white-tailed deer carotid body, cervical lymph nodes and ganglia.

Chronic wasting disease (CWD) is a transmissible and fatal prion disease that affects cervids. While both oral and nasal routes of exposure to prions cause disease, the spatial and temporal details of how prions enter the central nervous system (CNS) are unknown. Carotid bodies (CBs) are structures that are exposed to blood-borne prions and are densely innervated by nerves that are directly connected to brainstem nuclei, known to be early sites of prion neuroinvasion. All CBs examined contained mast cells expressing the prion protein which is consistent with these cells playing a role in neuroinvasion following prionemia.

Effect of endothelin-1 on the blood pressure response to acute hypoxia and hyperoxia in healthy young men.

Endothelin-1 (ET-1) and its receptors are linked to increases in sensitivity of the chemoreceptors to hypoxic stress and the development of hypertension in preclinical models. We hypothesized ET receptor antagonism would lower resting blood pressure (BP) as well as the acute BP response to chemoreflex stress. Twenty-four men (31 ± 5 years, 26 ± 3 kg/m2) completed two study visits (control, bosentan). On each visit, BP was assessed under three conditions: (1) normoxia (FiO2 0.21), (2) chemoreflex excitation via hypoxia (FiO2 0.05-0.21), (3) chemoreflex inhibition via hyperoxia (FiO2 1.00). Bosentan increased plasma ET-1 (0.94 ± 0.90 to 1.27 ± 0.62 pg/mL, p = 0.004), supporting receptor blockade. Resting diastolic (73 ± 5 to 69 ± 7 mmHg, p = 0.007) and mean (93 ± 7 to 88 ± 7 mmHg, p = 0.005) BP were reduced following bosentan compared to control with no change in systolic BP (p = 0.507). The mean BP response to both acute hypoxia (-0.48 ± 0.38 to -0.25 ± 0.31 mmHg/%, p = 0.004) and hyperoxia (area under the curve -93 ± 108 to -27 ± 66 AU, p = 0.018) were attenuated following bosentan. Acute ET receptor inhibition attenuates the rise in BP during chemoreflex excitation as well as the fall in BP during chemoreflex inhibition in healthy young men. These data support a role for ET-1 in control of resting BP, possibly through a chemoreceptor-mediated mechanism.

Pediatric carotid body tumors: A case report and systematic review.

Carotid body tumors (CBTs), or chemodectomas, are rare, especially in the pediatric population. They often present with minimal symptoms, making timely diagnosis challenging. This case report and systematic review highlights a distinctive presentation and summarize the current evidence on pediatric CBTs. We report a case of a 13-year-old girl presenting with neck pain and a left-sided neck mass. After extensive evaluation, a Shamblin type III tumor was identified and removed surgically. Postoperatively, the patient experienced transient hypertension and significant dysphagia, both of which resolved within a few weeks with no permanent sequelae. Histology confirmed a benign paraganglioma. A systematic literature review of PubMed identified 29 cases from 23 published studies spanning from 1968 to 2024. The average age at diagnosis was 12.6 ± 3.6 years. The most common symptom was a neck mass or swelling, reported in 75% of cases (n = 21). Tumor sizes ranged from 1.3 to 8.0 cm, with Shamblin III being the most frequent classification. Gross total resection (n = 25 [89.3%]) alone or in combination with preoperative embolization (n = 10 [35.7%]) were the most common methods of management. In 62.1% of cases, there were no permanent complication or sequelae. The proximity to vital neurovascular structures and high vascularity in pediatric patients necessitates careful perioperative interdisciplinary management. Owing to their rarity and nonspecific presentation, CBTs often remain undiagnosed for years. They respond well to treatment, but can be fatal if untreated, underscoring the importance of including CBTs in the differential diagnosis of pediatric neck masses.

Distribution and morphology of serotonin transporter-immunoreactive type I cells in the rat carotid body.

The present study reexamined the immunolocalization of membranous serotonin transporter (SERT) in the rat carotid body, and demonstrated SERT-immunoreactive cells of unreported morphology. SERT was immunohistochemically localized in a very small population of cell clusters or single type I cells (2.8%) immunoreactive for synaptophysin, the marker of these cells. Intense SERT immunoreactivity outlined the perinuclear cytoplasm and multiple cytoplasmic processes of type I cells. Of SERT-immunoreactive type I cells, 14.6% and 32.6% were immunoreactive for tyrosine hydroxylase (TH) and dopamine beta-hydroxylase, respectively, while 75.9% were immunoreactive for serotonin (5-HT). 5-HT-immunoreactive products were localized in cell bodies rather than cytoplasmic processes. SERT-immunoreactive type I cells were composed of an oval cell body with multiple threads and spherical or elongated cytoplasmic processes. Clusters or single SERT-immunoreactive type I cells were localized between or attached to other TH-immunoreactive type I cells by cell bodies or variform cytoplasmic processes. SERT-immunoreactive type I cells mainly contained bassoon-immunoreactive products in their cell bodies rather than their variform cytoplasmic processes. These results demonstrated the characteristic morphology of SERT-immunoreactive type I cells, which extend multiple cytoplasmic processes with variform terminal parts. Their morphology might be suitable for uptake of 5-HT to control the serotonergic modulation in the carotid body.

The Efficiency of Preoperative Embolization in the Management of Shamblin Type III Carotid Body Tumor: A Single-Center Retrospective Study.

BACKGROUND: This study aims to determine the efficacy and safety of preoperative embolization in the management of Shamblin type III carotid body tumors (CBT). METHOD: In this retrospective study, patients with Shamblin type III CBT were included between January 2005 and January 2017. A total of 48 Patients were divided into preoperative embolization (SRE, n = 25) and non-preoperative embolization group (SR, n = 23). RESULT: Mean surgical time (145.24 ± 19.86 min vs 186.91 ± 17.808 min, P < 0.05) and intraoperative blood loss (271.4 ± 73.001 mL vs 380.36 ± 39.822 mL, P < 0.05) were markedly reduced in the SRE group compared with SR group. The preoperative tumor volume in the SRE group was larger than that in the SR group, but the volume was similar between the two groups after surgery. The number of tumor residual cases was higher in the SR group. The incidence of complications and duration of hospitalization were comparable between the two groups. CONCLUSION: This study demonstrates the efficacy of preoperative embolization in reducing the duration of surgery and volume of blood loss during the process of CBT resection. More prospective, well-designed studies are urgently needed to validate the current findings.

Low-intensity focused ultrasound combined with microbubbles for non-invasive downregulation of rabbit carotid body activity in the treatment of hypertension.

Targeting the carotid body (CB) is a new approach in treating hypertension. This study investigates the efficacy and safety of ultrasound combined with microbubbles in targeting CB to treat hypertension. Twenty-seven hypertensive rabbits were randomly assigned to three groups: microbubbles only (sham group, n = 11), ultrasound plus microbubbles (LIFU group, n = 11), and bilateral carotid sinus nerve denervation (CSND group, n = 5). Four weeks post-intervention, blood pressure, hypoxic ventilatory response (HVR), blood pressure variability (BPV), heart rate variability (HRV), biochemical indicators, neurohormones, and histopathology were assessed in all groups. The results indicated significant reductions in systolic and diastolic blood pressure in the LIFU and CSND groups post-intervention, along with decreases in BPV, HRV, and catecholamines. HVR results showed a 35.10% reduction in CB activity in the LIFU group compared to the sham group, which was significantly lower than the reduction in the CSND group compared to the sham group (73.85%). Histopathology and transmission electron microscopy confirmed CB damage and cell apoptosis, with immunofluorescence showing a reduction in type I and II cells. In conclusion, LIFU combined with microbubbles can reduce blood pressure by lowering CB and sympathetic nerve activity.

Ruptured carotid artery pseudoaneurysm following excision of a carotid body tumor: a rare complication managed successfully with surgery and literature review.

A 47-year-old male presented with a right-sided Shamblin type 2 carotid body tumor measuring 5*5 cm. After preoperative embolization, a sub adventitial resection of the tumor was done. He was discharged after postoperative day 5 and presented again to emergency 10 days later with a bleeding pseudoaneurysm at the surgical site causing dysphagia and dyspnea. He was taken for emergency exploration of the surgical wound and, intraoperatively, it was observed that the proximal ends of the internal carotid artery and external carotid artery close to the bifurcation were forming a pseudoaneurysm, 1 cm distal to the common carotid artery. The external carotid artery was ligated and a common carotid to internal carotid artery bypass was done with a reversed saphenous vein graft. He recovered well in the postoperative period and was discharged on day 7. Pseudoaneurysm formation following carotid body tumor resection is extremely rare and has only been reported thrice in the literature.

Um homem de 47 anos apresentou tumor carotídeo Shamblin tipo 2 no lado direito, medindo 5 x 5 cm. Após embolização pré-operatória, foi realizada ressecção subadventicial do tumor. O paciente teve alta no quinto dia pós-operatório e voltou à emergência 10 dias depois, com pseudoaneurisma hemorrágico no sítio operatório causando disfagia e dispneia. Foi levado para exploração emergencial da ferida cirúrgica, e, no intraoperatório, 1 cm distalmente à artéria carótida comum, as extremidades proximais da artéria carótida interna e da artéria carótida externa próximas à bifurcação formavam um pseudoaneurisma. A artéria carótida externa foi ligada, e foi realizada uma ponte de safena de carótida comum para a artéria carótida interna com a veia safena invertida. O paciente se recuperou bem no pós-operatório e recebeu alta no sétimo dia. A formação de pseudoaneurisma após ressecção de tumor do corpo carotídeo é extremamente rara, tendo sido relatada apenas três vezes na literatura.

Percutaneous preoperative embolization with onyx in the management of a carotid body tumor: A case report.

Carotid body tumors (CBTs) are rare, hypervascular neuroendocrine neoplasms that can lead to significant complications during surgical resection due to the high risk of bleeding. We present the case of a 64-year-old male with a palpable neck mass on the left side, diagnosed as a CBT through imaging studies. Given the tumor's increasing size and rich vascularization, percutaneous preoperative embolization with Onyx under ultrasound and angiographic guide, was performed to minimize intraoperative complications. Forty-eight hours later, the tumor was surgically resected with minimal blood loss and no injury to cranial nerves or the carotid bifurcation.

Reductive stress in mitochondria isolated from the carotid body of type 1 diabetic male Wistar rats.

The carotid body (CB) senses changes in arterial O2 partial pressure (pO2) and glucose levels; therefore, it is key for the detection of hypoxia and hypoglycemia. The CB has been suggested to detect pO2 through an increase in reactive oxygen species (ROS) in the mitochondria. However, the mechanism protecting the chemoreceptor cells and their mitochondria from ROS and hyperglycemia is poorly understood. Here we measured glutathione levels in CB mitochondria of control and in streptozotocin (STZ)-induced type 1 diabetic male Wistar rats. We found a dramatic reduction in total glutathione from 11.45 ± 1.30 µmol/mg protein in control rats to 1.45 ± 0.31 µmol/mg protein in diabetic rats. However, the ratio of reduced to oxidized glutathione, a measure of the redox index, was increased in diabetic rats compared to controls. We conclude that the mitochondria of CB chemoreceptor cells in type 1 diabetic male Wistar rats were likely under glutathione-reducing stress.

Management of bilateral head and neck paragangliomas at a single-institution across four decades.

BACKGROUND: Bilateral head and neck paragangliomas (HNPGLs) require nuanced management to balance tumor control with functional preservation. METHODS: All patients seen at a single-institution for bilateral paraganglioma between 1983 and 2023 were retrospectively reviewed. Demographics, genetic testing results, and tumor characteristics were analyzed and compared to treatment modality and cranial nerve outcomes. RESULTS: There were 49 patients with 116 tumors (90 carotid body tumors [CBTs], 15 vagal paragangliomas [VPs], and 11 jugular paragangliomas [JPs]). Twenty-six patients had SDH pathologic variants (PV). Surgical management was more commonly utilized in younger patients (OR: 0.97, 95% CI: 0.950-0.992) and for JPs (OR: 9, 95% CI: 1.386-58.443). In surgical cases, CBTs had a lower risk of postoperative cranial nerve deficits compared to JPs and VPs (OR: 0.095, 95% CI: 0.013-0.692). CONCLUSIONS: Younger patients with bilateral HNPGLs, especially those with JP and CBT, are more often treated with surgery. CBTs have lowest risk of cranial nerve deficits after surgery.

Recovery of ventilatory and metabolic responses to hypoxia in neonatal rats after chronic hypoxia.

Chronic hypoxia (CH) during postnatal development attenuates the hypoxic ventilatory response (HVR) in mammals, but there are conflicting reports on whether this plasticity is permanent or reversible. This study tested the hypothesis that CH-induced respiratory plasticity is reversible in neonatal rats and investigated whether the initial plasticity or recovery differs between sexes. Rat pups were exposed to 3 d of normobaric CH (12 % O2) beginning shortly after birth. Ventilation and metabolic CO2 production were then measured in normoxia and during an acute hypoxic challenge (12 % O2) immediately following CH and after 1, 4-5, and 7 d in room air. CH pups hyperventilated when returned to normoxia immediately following CH, but normoxic ventilation was similar to age-matched control rats within 7 d after return to room air. The early phase of the HVR (minute 1) was only blunted immediately following the CH exposure, while the late phase of the HVR (minute 15) remained blunted after 1 and 4-5 d in room air; recovery appeared complete by 7 d. However, when normalized to CO2 production, the late phase of the hypoxic response recovered within only 1 d. The initial blunting of the HVR and subsequent recovery were similar in female and male rats. Carotid body responses to hypoxia (in vitro) were also normal in CH pups after approximately one week in room air. Collectively, these data indicate that ventilatory and metabolic responses to hypoxia recover rapidly in both female and male neonatal rats once normoxia is restored following CH.

[Endothelial cells and fibroblasts mediate the microenvironmental regulatory network of carotid body paraganglioma].

Objective:To explore the gene expression characteristics of endothelial cells and fibroblasts in the microenvironment of SDHD-mutated carotid body tumors（SDHD-CBT）, to fine the functional enrichment of each subcluster, and to further explore the network of cell-cell interactions in the microenvironment of SDHD-CBT. Methods:The bioinformatics analysis was used to download and reanalyze the single-nuclear RNA sequencing data of SDHD-CBT, SDHB mutated thoracic and abdominal paraganglioma（SDHB-ATPGL）, SDHB-CBT, and normal adrenal medulla（NAM）, to clarify the information of cell populations of the samples. We focused on exploring the gene expression profiles of endothelial cells and fibroblasts subclusters, and performed functional enrichment analysis based on Gene Ontology（GO） resources. CellChat was used to compare the cell-cell interactions networks of different clinical samples and predict significant signaling pathways in SDHD-CBT. Results:A total of 7 cell populations were profiled. The main subtypes of endothelial cells in SDHD-CBT are arterial and venous endothelial cells, and the main subtypes of fibroblasts are myofibroblasts and pericytes. Compared to NAM, SDHB-CBT and SDHB-ATPGL, cell communication involving endothelial cells and fibroblasts in SDHD-CBT is more abundant, with significant enrichment in pathways such as FGF, PTN, WNT, PROS, PERIOSTIN, and TGFb. Conclusion:Endothelial cells and fibroblasts in SDHD-CBT are heterogeneous and involved in important cellular interactionprocesses, in which the discovery of FGF，PTN，WNT，PROS，PERIOSTIN and TGFb signals may play an important role in the regulation of microenvironment of SDHD-CBT.

[To introduce a new method of resection of carotid body tumor with preservation of the internal carotid artery ----microscopic coagulation method].

Objective:To introduce the surgical experience of carotid body tumor（CBT） resection with preservation of internal carotid artery. Methods:The clinical data of 109 patients with CBT were retrospectively analyzed. The key points of surgical techniques were summarized, the imaging and pathological results were comprehensively analyzed, and the postoperative complications were observed. Results:Of the 109 patients, 28 were Shamblin Ⅰ, 46 were Shamblin Ⅱ, and 35 were Shamblin Ⅲ. Synaptophysin（SYN） and soluble protein-100（S-100） were positive in all cases. There was a positive correlation between the average expression area percentage of S-100 and SYN in pathological tissue of 17 patients（r=0.48）, and the difference was statistically significant（P<0.05）. The average operation time was（148.4±46.2） minutes, the average intraoperative blood loss was（64.7±22.8） mL, and the average hospital stay was（15.2±2.6） days. Three patients underwent tumor resection combined with external carotid artery ligation, 1 patient underwent tumor resection combined with internal carotid artery ligation, and the remaining patients underwent tumor resection alone. The overall rate of intraoperative vascular ligation was 3.7% and the rate of nerve injury was 6.4%. According to preoperative CTA, intraoperative situation and postoperative pathological results, a new classification of CBT was proposed, which could intuitively reflect the gap between the tumor and the carotid artery and the nature of the tumor. Conclusion:Surgical resection of CBT is recommended after diagnosis. The potential gap between the tumor and the blood vessels was found under the microscope. Low energy bipolar electrocoagulation was used to coagulate and cut off the fibrous connective tissue between the tumor and gradually separated along the adventitia of the artery. The carotid artery could be preserved in most cases while the tumor was completely removed, and the amount of intraoperative bleeding and the incidence of complications were reduced. It is particularly important to identify the difficult cases before operation.

Carotid body interoception in health and disease.

Interoception entails perceiving or being aware of the internal state of the body, playing a pivotal role in regulating processes such as heartbeat, digestion, glucose metabolism, and respiration. The carotid body (CB) serves as an interoceptive organ, transmitting information to the brain via its sensitive nerve, the carotid sinus nerve, to maintain homeostasis. While traditionally known for sensing oxygen, carbon dioxide, and pH levels, the CB is now recognized to possess additional interoceptive properties, detecting various mediators involved in blood pressure regulation, inflammation, and glucose homeostasis, among other physiological functions. Furthermore, in the last decades CB dysfunction has been linked to diseases like sleep apnea, essential hypertension, and diabetes. In this review manuscript, we make a concise overview of the traditional interoceptive functions of the CB, acting as a sensor for oxygen levels, carbon dioxide levels, and pH, and introduce the novel interoceptive properties of the CB related to vascular, glucose and energy regulation. Additionally, we revise the contribution of the CB to the onset and progression of metabolic diseases, delving into the potential dysfunction of its interoceptive metabolic functions as a contributing factor to pathophysiology. Finally, we postulate the use of therapeutic interventions targeting the metabolic interoceptive properties of the CB as a potential avenue for addressing metabolic diseases.

A 37-year-old female with a carotid body tumor (paraganglioma): A rare case report from Syria.

INTRODUCTION AND IMPORTANCE: This case study presents the clinical details of a 37-year-old woman who presented with an asymptomatic swelling in the right supraclavicular region, ultimately diagnosed as a carotid body tumor (CBT). CASE PRESENTATION: The patient's medical background, which included her brother's CBT, prompted further investigation. Upon clinical examination and imaging studies, a tissue mass surrounding the right internal carotid artery was identified. Subsequent surgical resection of the tumor was performed, and histological analysis confirmed a neoplastic proliferation consistent with paraganglioma. CLINICAL DISCUSSION: This case highlights the significance of taking into account familial history and conducting comprehensive diagnostic assessments for patients exhibiting similar symptoms. The successful multidisciplinary management of this rare tumor underscores the importance of early detection and appropriate therapeutic interventions. CONCLUSION: This report offers valuable insights into the clinical presentation, diagnostic process, and treatment of CBTs, emphasizing the necessity for a comprehensive approach to managing this uncommon neoplasm.

Role of the peripheral chemoreceptors in cardiovascular and metabolic control in type 2 diabetes.

Preclinical work supports a role for the peripheral chemoreceptors in the progression of cardiovascular and metabolic pathologies. In the present study, we examined peripheral chemosensitivity in adults with type 2 diabetes (T2D) and the contribution of the peripheral chemoreceptors to resting cardiovascular and metabolic control. We hypothesized that: (1) adults with T2D exhibit exaggerated peripheral chemoreflex sensitivity; (2) the peripheral chemoreceptors contribute to cardiovascular dysfunction in T2D; and (3) attenuation of peripheral chemoreceptor activity improves glucose tolerance in T2D. Seventeen adults with diagnosed T2D [six males/11 females; aged 54 ± 11 years; glycated haemoglobin (HbA1c) 7.6 ± 1.5%] and 20 controls without T2D (9 males/11 females; aged 49 ± 13 years, HbA1c 5.2 ± 0.4%) participated in the study. The hypoxic ventilatory response (HVR) was assessed as an index of peripheral chemosensitivity. Resting heart rate, blood pressure and minute ventilation were measured when breathing normoxic followed by hyperoxic air (1.0 F I O 2 ${{F}_{{\mathrm{I}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$ ) to acutely attenuate peripheral chemoreceptor activity. A subset of participants (n = 9 per group) completed two additional visits [normoxia (0.21 F I O 2 ${{F}_{{\mathrm{I}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$ ), hyperoxia (1.0 F I O 2 ${{F}_{{\mathrm{I}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$ )] where glucose and insulin were measured for 2 h following an oral glucose challenge. HVR was augmented in adults with T2D (-0.84 ± 0.49 L min-1/%) vs. control (-0.48 ± 0.40 L min-1/%, P = 0.021). Attenuation of peripheral chemoreceptor activity decreased heart rate (P < 0.001), mean blood pressure (P = 0.009) and minute ventilation (P = 0.002); any effect of hyperoxia did not differ between groups. There was no effect of hyperoxia on the glucose (control, P = 0.864; T2D, P = 0.982), nor insulin (control, P = 0.763; T2D, P = 0.189) response to the oral glucose challenge. Peripheral chemoreflex sensitivity is elevated in adults with T2D; however, acute attenuation of peripheral chemoreflex activity with hyperoxia does not restore cardiometabolic function. KEY POINTS: Preclinical work supports a role for the peripheral chemoreceptors in the progression of cardiovascular and metabolic pathologies. In the present study, we examined peripheral chemosensitivity in adults with type 2 diabetes and the contribution of the peripheral chemoreceptors to resting cardiovascular control and glucose tolerance. We observed elevated peripheral chemoreflex sensitivity in adults with diabetes which was associated with glycaemic control (i.e. glycated haemoglobin). Notably, acute attenuation of peripheral chemoreflex activity with hyperoxia did not restore cardiometabolic function in the individuals studied.