Use of sidestream dark-field (SDF) imaging for assessing the effects of high-dose melphalan and autologous stem cell transplantation on oral mucosal microcirculation in myeloma patients

Dose-related effects of norepinephrine on early-stage endotoxemic shock in a swine model

Background

The benefits of early use of norepinephrine in endotoxemic shock remain unknown. We aimed to elucidate the effects of different doses of norepinephrine in early-stage endotoxemic shock using a clinically relevant large animal model.

Methods

Vasodilatory shock was induced by endotoxin bolus in 30 Bama suckling pigs. Treatment included fluid resuscitation and administration of different doses of norepinephrine, to induce return to baseline mean arterial pressure (MAP). Fluid management, hemodynamic, microcirculation, inflammation, and organ function variables were monitored. All animals were supported for 6 h after endotoxemic shock.

Results

Infused fluid volume decreased with increasing norepinephrine dose. Return to baseline MAP was achieved more frequently with doses of 0.8 µg/kg/min and 1.6 µg/kg/min (P <0.01). At the end of the shock resuscitation period, cardiac index was higher in pigs treated with 0.8 µg/kg/min norepinephrine (P <0.01), while systemic vascular resistance was higher in those receiving 0.4 µg/kg/min (P <0.01). Extravascular lung water level and degree of organ edema were higher in animals administered no or 0.2 µg/kg/min norepinephrine (P <0.01), while the percentage of perfused small vessel density (PSVD) was higher in those receiving 0.8 µg/kg/min (P <0.05) and serum lactate was higher in the groups administered no and 1.6 µg/kg/min norepinephrine (P <0.01).

Conclusions

The impact of norepinephrine on the macro- and micro-circulation in early-stage endotoxemic shock is dose-dependent, with very low and very high doses resulting in detrimental effects. Only an appropriate norepinephrine dose was associated with improved tissue perfusion and organ function.

Patient-Side Appraisal of Late Radiation-Induced Oral Microvascular Changes

PURPOSE

To determine the clinical feasibility of examining and measuring late irradiation changes in the oral microcirculation of head and neck (HN) cancer patients using the novel CytoCam video microscope system.

METHODS AND MATERIALS

In 30 HN cancer patients and 30 age-matched controls, bilateral video images were recorded noninvasively of the oral microcirculation of the buccal mucosa and mandibular gingiva. Tissue perfusion parameters, such as functional capillary density (FCD), buccal blood vessel diameter, and microcirculatory flow index, were analyzed.

RESULTS

No difference was observed for mean buccal mucosa FCD in irradiated versus healthy tissue, whereas a lower mean gingival FCD in irradiated versus healthy tissue was observed (34 ± 17 capillaries per millimeter squared [cpll/mm²] vs 68 ± 19 cpll/mm²; P < .001). A significant difference in mean buccal blood vessel diameter of 16 ± 3 μm was measured, compared with 14 ± 1 μm in control buccal mucosa (P < .001). No significant difference in microcirculatory flow index was observed between the 2 groups.

CONCLUSIONS

Quantifying oral microcirculatory injury associated with late irradiation effects using the CytoCam was feasible in HN cancer patients. Results indicate that marked differences in tissue-specific microcirculatory measurements of angioarchitecture, diminished capillary density, and extensively dilated blood vessel diameters are associated with late irradiation effects in HN cancer patients.

In-vivo longitudinal imaging of microvascular changes in irradiated oral mucosa of radiotherapy cancer patients using optical coherence tomography

Mucositis is the limiting toxicity of radio(chemo)therapy of head and neck cancer. Diagnostics, prophylaxis and correction of this condition demand new accurate and objective approaches. Here we report on an in vivo longitudinal monitoring of the oral mucosa dynamics in 25 patients during the course of radiotherapy of oropharyngeal and nasopharyngeal cancer using multifunctional optical coherence tomography (OCT). A spectral domain OCT system with a specially-designed oral imaging probe was used. Microvasculature visualization was based on temporal speckle variations of the full complex signal evaluated by high-pass filtering of 3D data along the slow scan axis. Angiographic image quantification demonstrated an increase of the vascular density and total length of capillary-like-vessels before visual signs or clinical symptoms of mucositis occur. Especially significant microvascular changes compared to their initial levels occurred when grade two and three mucositis developed. Further, microvascular reaction was seen to be dose-level dependent. OCT monitoring in radiotherapy offers a non-invasive, convenient, label-free quantifiable structural and functional volumetric imaging method suitable for longitudinal human patient studies, furnishing fundamental radiobiological insights and potentially providing useful feedback data to enable adaptive radiotherapy (ART).

Evaluation of Mannose-Binding Lectin is a Useful Approach to Predict the Risk of Infectious Complications Following Autologous Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT) associated immunocompromised state carries high risk of infectious complications. Mannose-binding lectin (MBL) is an acute phase protein involved in innate immune response. Serum MBL level is genetically determined and quite stable. According to literature, significant association was shown between low MBL concentrations and serious infections. The association between serum MBL level and frequency and severity of infections was studied in 186 patients following autologous HSCT. Double-monoclonal antibody sandwich enzyme-linked immunosorbent assay was used to determine MBL antigen level in sera. MBL levels were measured around 100 days following transplantation, in a period without active infection. Twenty-one patients (11%) were MBL deficient. The median time of first infection and number of infections during the first year post-transplantation were not significantly different between patients with MBL deficiency and those without MBL deficiency. The occurrence and number of infections after HSCT correlated with the MBL/C-reactive protein ratio. The number of severe infections was not higher among those with MBL deficiency. The occurrence of infections after the pre-engraftment period during the first year post-transplantation was significantly different in patient groups separated by MBL cut-off level. The MBL/C-reactive protein ratio might be a useful marker of infectious complications. MBL measurement may be helpful in antibiotic treatment. In case of MBL deficiency, earlier and more intensive treatment may be indicated.

Why Rudolph's nose is red: observational study

OBJECTIVE

To characterise the functional morphology of the nasal microcirculation in humans in comparison with reindeer as a means of testing the hypothesis that the luminous red nose of Rudolph, one of the most well known reindeer pulling Santa Claus's sleigh, is due to the presence of a highly dense and rich nasal microcirculation.

DESIGN

Observational study.

SETTING

Tromsø, Norway (near the North Pole), and Amsterdam, the Netherlands.

PARTICIPANTS

Five healthy human volunteers, two adult reindeer, and a patient with grade 3 nasal polyposis.

MAIN OUTCOME MEASURES

Architecture of the microvasculature of the nasal septal mucosa and head of the inferior turbinates, kinetics of red blood cells, and real time reactivity of the microcirculation to topical medicines.

RESULTS

Similarities between human and reindeer nasal microcirculation were uncovered. Hairpin-like capillaries in the reindeers' nasal septal mucosa were rich in red blood cells, with a perfused vessel density of 20 (SD 0.7) mm/mm(2). Scattered crypt or gland-like structures surrounded by capillaries containing flowing red blood cells were found in human and reindeer noses. In a healthy volunteer, nasal microvascular reactivity was demonstrated by the application of a local anaesthetic with vasoconstrictor activity, which resulted in direct cessation of capillary blood flow. Abnormal microvasculature was observed in the patient with nasal polyposis.

CONCLUSIONS

The nasal microcirculation of reindeer is richly vascularised, with a vascular density 25% higher than that in humans. These results highlight the intrinsic physiological properties of Rudolph's legendary luminous red nose, which help to protect it from freezing during sleigh rides and to regulate the temperature of the reindeer's brain, factors essential for flying reindeer pulling Santa Claus's sleigh under extreme temperatures.

Oral mucositis: the new paradigms

PURPOSE OF REVIEW

Mucositis has long been viewed as an unavoidable consequence of high-dose chemotherapy and/or radiation. Management has been directed to supportive care including oral pain control, nutritional support, infection treatment and control of diarrhea. Whereas these interventions have been valuable for clinical management, they have not been collectively directed to molecularly targeted prevention and treatment. This review addresses recent advances regarding mucosal injury in cancer patients, with emphasis on symptom clusters, genetically based tissue susceptibility and risk prediction, imaging technology, and computational biology.

RECENT FINDINGS

Modeling of symptom clusters in cancer patients continues to mature. Although integration of mucositis into the paradigm is at an early stage, recent studies suggest that important molecular and clinical insights will emerge in this regard. Initial studies of genetic-based tissue risk are also providing a research basis that may lead to clinical risk prediction models. These advances are in part being engineered via new imaging and computational biology technologies, drawing upon literature in nonmucositis systems. Just as the past decade has been hallmarked by linkage of pathobiology with clinical expression of mucosal toxicity, the next decade promises to identify new molecular interactions and risk prediction models based on novel application of the analytic technologies.

SUMMARY

Recent research has culminated in convergence of molecular pathobiology with models of symptom clusters, genetic-based risk, and imaging and computational biology. The field is poised to further delineate this paradigm, with the goal of development of molecularly targeted drugs and devices for mucositis management.

Oral mucositis

Mucosal damage is one of the most common adverse effects of radiotherapy and of cytotoxic therapy for cancer. With prevalence between 10% and 100%, depending of the cytotoxic regimen and patient-associated variables, this morbid condition represents a significant problem in oncology. In this paper we address oral mucositis and discuss its pathobiology, risk factors, impact and management in view of the most recent evidence. Despite of clear progress and the development of clinical guidelines, what we currently have to offer to patients to manage mucositis and oropharyngeal pain is still inadequate. Expansion of the knowledge of the pathogenesis of mucositis as well as a better insight into individual risk factors will provide opportunities to improve management strategies.