Intranasal delivery of mitochondria targeted neuroprotective compounds for traumatic brain injury: screening based on pharmacological and physiological properties

Targeting drugs to the mitochondrial level shows great promise for acute and chronic treatment of traumatic brain injury (TBI) in both military and civilian sectors. Perhaps the greatest obstacle to the successful delivery of drug therapies is the blood brain barrier (BBB). Intracerebroventricular and intraparenchymal routes may provide effective delivery of small and large molecule therapies for preclinical neuroprotection studies. However, clinically these delivery methods are invasive, and risk inadequate exposure to injured brain regions due to the rapid turnover of cerebral spinal fluid. The direct intranasal drug delivery approach to therapeutics holds great promise for the treatment of central nervous system (CNS) disorders, as this route is non-invasive, bypasses the BBB, enhances the bioavailability, facilitates drug dose reduction, and reduces adverse systemic effects. Using the intranasal method in animal models, researchers have successfully reduced stroke damage, reversed Alzheimer's neurodegeneration, reduced anxiety, improved memory, and delivered neurotrophic factors and neural stem cells to the brain. Based on literature spanning the past several decades, this review aims to highlight the advantages of intranasal administration over conventional routes for TBI, and other CNS disorders. More specifically, we have identified and compiled a list of most relevant mitochondria-targeted neuroprotective compounds for intranasal administration based on their mechanisms of action and pharmacological properties. Further, this review also discusses key considerations when selecting and testing future mitochondria-targeted drugs given intranasally for TBI.

Revert total protein normalization method offers a reliable loading control for mitochondrial samples following TBI

Owing to evidence that mitochondrial dysfunction plays a dominant role in the traumatic brain injury (TBI) pathophysiology, the Western blot (WB) based immunoblotting method is widely employed to identify changes in the mitochondrial protein expressions after neurotrauma. In WB method, the housekeeping proteins (HKPs) expression is routinely used as an internal control for sample normalization. However, the traditionally employed HKPs can be susceptible to complex cascades of TBI pathogenesis, leading to their inconsistent expression. Remarkably, our data illustrated here that mitochondrial HKPs, including Voltage-dependent anion channels (VDAC), Complex-IV, Cytochrome C and Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) yielded altered expressions following penetrating TBI (PTBI) as compared to Sham. Therefore, our goal was to identify more precise normalization procedure in WB. Adult male Sprague Dawley rats (N = 6 rats/group) were used to perform PTBI, and the novel REVERT Total Protein (RTP) method was used to quantify mitochondrial protein load consistency between samples at 6 h and 24 h post-injury. Notably, the RTP method displayed superior protein normalization compared to HKPs method with higher sensitivity at both time-points between experimental groups. Our data favors application of RTP based normalization to accurately quantify protein expression where inconsistent HKPs may be evident in neuroscience research.

Comprehensive evaluation of mitochondrial redox profile, calcium dynamics, membrane integrity and apoptosis markers in a preclinical model of severe penetrating traumatic brain injury

Traumatic Brain Injury (TBI) is caused by the external physical assaults damages the brain. It is a heterogeneous disorder that remains a leading cause of death and disability in the military and civilian population of the United States. Preclinical investigations of mitochondrial responses in TBI have ascertained that mitochondrial dysfunction is an acute indicator of cellular damage and plays a pivotal role in long-term injury progression through cellular excitotoxicity. The current study was designed to provide an in-depth evaluation of mitochondrial endpoints with respect to redox and calcium homeostasis, and cell death responses following penetrating TBI (PTBI). To evaluate these pathological cascades, anesthetized adult male rats (N = 6/group) were subjected to either 10% unilateral PTBI or Sham craniectomy. Animals were euthanized at 24 h post-PTBI, and purified mitochondrial fractions were isolated from the brain injury core and perilesional areas. Overall, increased reactive oxygen and nitrogen species (ROS/RNS) production, and elevated oxidative stress markers such as 4-hydroxynonenal (4-HNE), 3-nitrotyrosine (3-NT), and protein carbonyls (PC) were observed in the PTBI group compared to Sham. Mitochondrial antioxidants such as glutathione, peroxiredoxin (PRX-3), thioredoxin (TRX), nicotinamide adenine dinucleotide phosphate (NADPH), superoxide dismutase (SOD), and catalase (CAT) levels were significantly decreased after PTBI. Likewise, PTBI mitochondria displayed significant loss of Ca²⁺ homeostasis, early opening of mitochondrial permeability transition pore (mPTP), and increased mitochondrial swelling. Both, outer and inner mitochondrial membrane integrity markers, such as voltage-dependent anion channels (VDAC) and cytochrome c (Cyt C) expression were significantly decreased following PTBI. The apoptotic cell death was evidenced by significantly decreased B-cell lymphoma-2 (Bcl-2) and increased glyceraldehyde 3-phosphate dehydrogenase (GAPDH) expression after PTBI. Collectively, current results highlight the comprehensive picture of mitochondria-centric acute pathophysiological responses following PTBI, which may be utilized as novel prognostic indicators of disease progression and theragnostic indicators for evaluating neuroprotection therapeutics following TBI.

Effects of sequential aeromedical evacuations following traumatic brain injury in swine

INTRODUCTION

Traumatic brain injuries (TBI) represent a significant percentage of critical injuries in military conflicts. Following injury, wounded warfighters are often subjected to multiple aeromedical evacuations (AE) and associated hypobaria, yet the impact in TBI patients remains to be characterized. This study evaluated the impact of two consecutive simulated AEs in a fluid-percussion TBI model in swine to characterize these effects.

METHODS

Following instrumentation, anesthetized Yorkshire swine underwent a frontal TBI via fluid-percussion. A hypobaric chamber was then used to simulate AE at simulated cabin pressure equivalent to 8000ft (hypobaria) in a 6 h initial flight on day 3, followed by a 9 h flight on day 6, and were monitored for 14 days. Animals in the normobaria group were subjected to the same steps at sea level while Sham animals in both groups were instrumented but not injured. Parameters measured included physiologic response, intracranial pressure (ICP), hematology, chemistry, and serum cytokines. Histopathology of brain, lung, intestine, and kidney was performed, as well as fluorojade staining to evaluate neurodegeneration. All animals were divided into sub-groups by block randomization utilizing a 2-way ANOVA to analyze independent variables.

RESULTS

Survival was 100% in all groups. Physiologic parameters were largely similar across groups as well during both 6 and 9 h AE. Animals exposed to hypobaria in both the TBI and Sham groups had elevated heart rate (HR) during the 6 h flight (p<0.05). Three animals in the TBI hypo group demonstrated leukocytosis with histologic evidence of meningeal inflammatory response. Expression of serum cytokines was low across all groups. No significant neuronal degeneration was identified in areas away from the site of injury.

CONCLUSION

Aeromedical evacuation in swine was not associated with significant differences in physiologic measures, cytokine expression or levels of neuronal degeneration. Histological examination revealed higher risk of meningeal inflammatory response and leucocytosis in swine exposed to hypobaria.

Histopathological Evidence of Multiple Organ Damage After Simulated Aeromedical Evacuation in a Swine Acute Lung Injury Model

INTRODUCTION

Rapid aeromedical evacuation (AE) is standard of care in current conflicts. However, not much is known about possible effects of hypobaric conditions. We investigated possible effects of hypobaria on organ damage in a swine model of acute lung injury.

METHODS

Lung injury was induced in anesthetized swine via intravenous oleic acid infusion. After a stabilization phase, animals were subjected to a 4 hour simulated AE at 8000 feet (HYPO). Control animals were kept at normobaria. After euthanasia and necropsy, organ damage was assessed by combined scores for hemorrhage, inflammation, edema, necrosis, and microatelectasis.

RESULTS

Hemodynamic, neurological, or hematologic measurements were similar prior to transport. Hemodynamic instability became apparent during the last 2 hours of transport in the HYPO group. Histological injury scores in the HYPO group were higher for all organs (lung, kidney, liver, pancreas, and adrenal glands) except the brain, with the largest difference in the lungs (P < 0.001).

CONCLUSIONS

Swine with mild acute lung injury subjected to a 4 hour simulated AE showed more injury to most organs and, in particular, to the lungs compared with ground transport. This may exacerbate otherwise subclinical pathology and, eventually, manifest as abnormalities in gas exchange or possibly end-organ function.

Hypobaria during aeromedical evacuation exacerbates histopathological injury and modifies inflammatory response in rats exposed to blast overpressure injury

BACKGROUND

Aeromedical evacuation (AE) is often used as a rapid and effective way to evacuate patients. However, little is known about the possible effects of AE on patients with blast and traumatic brain injury. In the current study, we used blast overpressure (BOP) as a method to introduce traumatic brain injury in rats and investigated the effects of hypobaria during AE on histology and inflammatory response.

METHODS

Animals were exposed to a 12-hour flight 2 days after BOP and euthanized 48 hours after flight. Control animals were kept at normobaria.

RESULTS

Overall, BOP animals exposed to flight demonstrated higher histopathologic injury scores as compared to control animals in lungs, brain, kidney, heart, and intestine. The BOP animals exposed to normobaria exhibited a proinflammatory response compared to those that were not blasted, an observation that was not seen in BOP animals exposed to hypobaria.

CONCLUSION

These data suggest that AE 48 hours post blast may lead to impairment in the inflammatory process and worsening of long-term outcomes.

LEVEL OF EVIDENCE

Animal research, level II.

Cerebral Microvascular and Systemic Effects Following Intravenous Administration of the Perfluorocarbon Emulsion Perftoran

Oxygen-carrying perfluorocarbon (PFC) fluids have the potential to increase tissue oxygenation during hypoxic states and to reduce ischemic cell death. Regulatory approval of oxygen therapeutics was halted due to concerns over vasoconstrictive side effects. The goal of this study was to assess the potential vasoactive properties of Perftoran by measuring brain pial arteriolar diameters in a healthy rat model. Perftoran, crystalloid (saline) or colloid (Hextend) solutions were administered as four sequential 30 min intravenous (IV) infusions, thus allowing an evaluation of cumulative dose-dependent effects. There were no overall changes in diameters of small-sized (<50 μm) pial arterioles within the Perftoran group, while both saline and Hextend groups exhibited vasoconstriction. Medium-sized arterioles (50–100 μm) showed minor (~8–9%) vasoconstriction within saline and Hextend groups and only ~5% vasoconstriction within the Perftoran group. For small- and medium-sized pial arterioles, the mean percent change in vessel diameters was not different among the groups. Although there was a tendency for arterial blood pressures to increase with Perftoran, pressures were not different from the other two groups. These data show that Perftoran, when administered to healthy anesthetized rats, does not cause additional vasoconstriction in cerebral pial arterioles or increase systemic blood pressure compared with saline or Hextend.

The Emulsified PFC Oxycyte® Improved Oxygen Content and Lung Injury Score in a Swine Model of Oleic Acid Lung Injury (OALI)

PURPOSE

Perfluorocarbons (PFCs) can transport 50 times more oxygen than human plasma. Their properties may be advantageous in preservation of tissue viability in oxygen-deprived states, such as in acute lung injury. We hypothesized that an intravenous dose of the PFC emulsion Oxycyte^® would improve tissue oxygenation and thereby mitigate the effects of acute lung injury.

METHODS

Intravenous oleic acid (OA) was used to induce lung injury in anesthetized and instrumented Yorkshire swine assigned to three experimental groups: (1) PFC post-OA received Oxycyte^® (5 ml/kg) 45 min after oleic acid-induced lung injury (OALI); (2) PFC pre-OA received Oxycyte^® 45 min before OALI; and (3) Controls which received equivalent dose of normal saline. Animals were observed for 3 h after OALI began, and then euthanized.

RESULTS

The median survival times for PFC post-OA, PFC pre-OA, and control were 240, 87.5, and 240 min, respectively (p = 0.001). Mean arterial pressure and mean pulmonary arterial pressure were both higher in the PFC post-OA (p < 0.001 for both parameters). Oxygen content was significantly different between PFC post-OA and the control (p = 0.001). Histopathological grading of lung injury indicated that edema and congestion was significantly less severe in the PFC post-OA compared to control (p = 0.001).

CONCLUSION

The intravenous PFC Oxycyte^® improves blood oxygen content and lung histology when used as a treatment after OALI, while Oxycyte^® used prior to OALI was associated with increased mortality. Further exploration in other injury models is indicated.

Sanguinate's effect on pial arterioles in healthy rats and cerebral oxygen tension after controlled cortical impact

Sanguinate, a polyethylene glycol-conjugated carboxyhemoglobin, was investigated for cerebral vasoactivity in healthy male Sprague-Dawley rats (Study 1) and for its ability to increase brain tissue oxygen pressure (PbtO2) after controlled cortical impact (CCI) - traumatic brain injury (TBI) (Study 2). In both studies ketamine-acepromazine anesthetized rats were ventilated with 40% O2. In Study 1, a cranial window was used to measure the diameters of medium - (50-100μm) and small-sized (<50μm) pial arterioles before and after four serial infusions of Sanguinate (8mL/kg/h, cumulative 16mL/kg IV), volume-matched Hextend, or normal saline. In Study 2, PbtO2 was measured using a phosphorescence quenching method before TBI, 15min after TBI (T15) and then every 10min thereafter for 155min. At T15, rats received either 8mL/kg IV Sanguinate (40mL/kg/h) or no treatment (saline, 4mL/kg/h). Results showed: 1) in healthy rats, percentage changes in pial arteriole diameter were the same among the groups, 2) in TBI rats, PbtO2 decreased from 36.5±3.9mmHg to 19.8±3.0mmHg at T15 in both groups after TBI and did not recover in either group for the rest of the study, and 3) MAP increased 16±4mmHg and 36±5mmHg after Sanguinate in healthy and TBI rats, respectively, while MAP was unchanged in control groups. In conclusion, Sanguinate did not cause vasoconstriction in the cerebral pial arterioles of healthy rats but it also did not acutely increase PbtO2 when administered after TBI. Sanguinate was associated with an increase in MAP in both studies.

Endovascular Cooling Method for Hypothermia in Injured Swine

We evaluated an endovascular cooling method to modulate core temperature in trauma swine models with and without fluid support. Anesthetized swine (N = 80) were uninjured (SHAM) or injured through a bone fracture plus soft tissue injury or an uncontrolled hemorrhage and then subdivided to target body temperatures of 38°C (normothermia) or 33°C (hypothermia) by using a Thermogard endovascular cooling device (Zoll Medical). Temperature regulation began simultaneously at onset of injury (T0). Body temperatures were recorded from a rectal probe (Rec Temp) and from a central pulmonary artery catheter (PA Temp). At T15, swine received 500 mL IV Hextend over 30 minutes or no treatment (NONE) with continued monitoring until 3 hours from injury. Hypothermia was attained in 105 ± 39 minutes, at a cooling rate of -0.061°C ± 0.007°C/min for NONE injury groups. Postinjury Hextend administration resulted in faster cooling (-0.080°C ± 0.006°C/min); target temperature was reached in 83 ± 11 minutes (p < 0.05). During active cooling, body temperature measured by the PA Temp was significantly cooler than the Rec Temp due to the probe's closer proximity to the blood-cooling catheter balloons (p < 0.05). This difference was smaller in SHAM and fluid-supported injury groups (1.1°C ± 0.4°C) versus injured NONE groups (2.1°C ± 0.3°C). Target temperatures were correctly maintained thereafter in all groups. In normothermia groups, there was a small initial transient overshoot to maintain 38°C. Despite the noticeable difference between PA Temp and Rec Temp until target temperature was attained, this endovascular method can safely induce moderate hypothermia in anesthetized swine. However, likely due to their compromised hemodynamic state, cooling in hypovolemic and/or injured patients will be different from those without injury or those that also received fluids.

Use of recombinant factor VIIa (rFVIIa) as pre-hospital treatment in a swine model of fluid percussion traumatic brain injury

CONTEXT

Recombinant factor VIIa (rFVIIa) has been used as an adjunctive therapy for acute post-traumatic hemorrhage and reversal of iatrogenic coagulopathy in trauma patients in the hospital setting. However, investigations regarding its potential use in pre-hospital management of traumatic brain injury (TBI) have not been conducted extensively.

AIMS

In the present study, we investigated the physiology, hematology and histology effects of a single pre-hospital bolus injection of rFVIIa compared to current clinical practice of no pre-hospital intervention in a swine model of moderate fluid percussion TBI.

MATERIALS AND METHODS

Animals were randomized to receive either a bolus of rFVIIa (90 μg/kg) or nothing 15 minutes (T15) post-injury. Hospital arrival was simulated at T60, and animals were euthanized at experimental endpoint (T360).

RESULTS

Survival was 100% in both groups; baseline physiology parameters were similar, vital signs were comparable. Animals that received rFVIIa demonstrated less hemorrhage in subarachnoid space (P = 0.0037) and less neuronal degeneration in left hippocampus, pons, and cerebellum (P = 0.00009, P = 0.00008, and P = 0.251, respectively). Immunohistochemical staining of brain sections showed less overall loss of microtubule-associated protein 2 (MAP2) and less Flouro-Jade B positive cells in rFVIIa-treated animals.

CONCLUSIONS

Early pre-hospital administration of rFVIIa in this swine TBI model reduced neuronal necrosis and intracranial hemorrhage (ICH). These results merit further investigation of this approach in pre-hospital trauma care.

Sodium nitroprusside ameliorates systemic but not pulmonary HBOC-201-induced vasoconstriction: an exploratory study in a swine controlled haemorrhage model

BACKGROUND

Vasoconstriction is a side effect that may prevent the use of haemoglobin based oxygen carrier (HBOC) as blood substitute. Therefore, we tested the hypothesis that the NO donor, sodium nitroprusside (SNP), would mitigate systemic and pulmonary hypertension associated with HBOC-201 in a simple controlled haemorrhage swine model.

METHODS

After 55% estimated blood volume withdrawal through a venous catheter, invasively anesthetized and instrumented animals were resuscitated with three 10 ml/kg infusions of either HBOC-201 or Hextend (HEX) with or without 0.8 μg/kg/min SNP (infused concomitantly via different lines). Haemodynamics, direct and indirect measures of tissue oxygenation, and coagulation were measured for 2h.

RESULTS

Haemorrhage caused a state of shock manifested by hypotension and base deficit. HBOC-201 resuscitation resulted in higher systemic (p<0.0001) and pulmonary (p<0.002) blood pressure than with HEX. Elevation of systemic (p<0.0001) but not pulmonary (p>0.05) arterial pressure was attenuated by co-infusion of SNP, without significant group differences in haemodynamics, tissue oxygenation, platelet function, coagulation, methaemoglobin, or survival (p>0.05).

CONCLUSION

In swine with haemorrhagic shock, co-administration of the NO donor, SNP, effectively and safely reduces HBOC-201-related systemic but not pulmonary vasoactivity. Interestingly, co-administration of the vasodilator SNP with HEX had no deleterious effects in comparison with HEX alone.

Pre-hospital resuscitation with HBOC-201 and rFVIIa compared to HBOC-201 alone in uncontrolled hemorrhagic shock in swine

In a previous dose escalation study our group found that combining 90μg/kg rFVIIa with HBOC-201 reduced blood loss and improved physiologic parameters compared to HBOC alone. In this follow-up study in a swine liver injury model, we found that while there were no adverse hematology effects and trends observed in the previous study were confirmed, statistical significance could not be reached. Additional pre-clinical studies are indicated to identify optimal components of a multifunctional blood substitute for clinical use in trauma.

Dose response of sodium nitrite on vasoactivity associated with HBOC-201 in a swine model of controlled hemorrhage

Sodium nitrite (NaNO(2)) was evaluated in a 55% EBV hemorrhage swine model to mitigate the increased blood pressure due to HBOC-201. Animals were resuscitated by three 10 ml/kg infusions of either HBOC-201 or Hextend with and without NaNO(2). All vital signs, coagulation and blood chemistry were measured for 2 hr. HBOC-201-vasoconstriction was attenuated only after the first 10.8 μmol/kg NaNO(2) infusion. Complete abolition was obtained with the highest 3 NaNO(2) dose, but side effects were observed. There was no reduction in platelet function due to NaNO(2). NaNO(2) ability to reduce HBOC-201 vasoactivity was transient and 10.8 μmol/kg NaNO(2) seems an acceptable dose for further investigation.

Microthrombectomy reduces postsclerotherapy pigmentation: multicenter randomized trial

OBJECTIVE

Postsclerotherapy pigmentation occurs in nearly 30% of patients. Hemosiderin, from degradation of the venous thrombus, is the possible cause. The hypothesis that early removal of the thrombus may eliminate or decrease the incidence of pigmentation has not been proved or documented. The objective of this study was to investigate the effects of early microthrombectomy on incidence of postsclerotherapy pigmentation.

MATERIAL AND METHODS

This multicenter, randomized, controlled study involved 101 patients with varicose veins (100 women, 1 man; mean age, 46 years [range, 25-68 years]). Patients were divided into two groups, with veins 1 mm or less in diameter (group 1, n = 50) or veins 3 mm or less in diameter (group 2, n = 51). Group 1 was treated with Sotradecol (STD) 0.25%, and group 2 with STD 0.50%. In each patient, an area of varicosities was selected and divided into halves. One half was randomized to microthrombectomy and the other half served as control. Microthrombectomy was performed 1 to 3 weeks after treatment in the randomized half. Standard photographs were obtained before and 16 weeks after treatment, and were evaluated by three independent reviewers who were blinded to treatment assignments. Each reviewer received an identical set of pretreatment and posttreatment 10 x 15-cm color photographs of the study area, and completed a scoring sheet. Average of the scores was used to evaluate primary (pigmentation) and secondary (overall clinical improvement) end points. The paired t test and chi-square test were used for statistical analysis.

RESULTS

In group 1, microthrombectomized areas had statistically significant less pigmentation (P =.0047) and better overall clinical improvement scores (P =.0002) compared with the control side. In group 2 there was no significant difference between the two areas, but patients reported significant relief of pain and inflammation associated with postsclerotherapy thrombophlebitis.

CONCLUSION

In veins 1 mm or smaller, microthrombectomy reduced pigmentation and improved overall clinical results. In veins 3 mm or smaller, statistical significance was not achieved, but thrombectomy resulted in faster resolution of the postsclerotherapy pain and inflammation. On the basis of these results, microthrombectomy after sclerotherapy is recommended.

The pelvic venous syndromes: analysis of our experience with 57 patients

BACKGROUND

The pelvic venous syndromes comprise a group of poorly understood disorders of the pelvic and gonadal venous circulation. The objective of this paper was to review our experience with the pelvic venous syndromes and, in the light of the current literature, make management recommendations.

MATERIALS AND METHODS

Fifty-seven female patients (age range, 24 to 48 years; mean, 34 years) with symptoms of pelvic pain, dysuria, dysmenorrhea, dyspareunia, and the presence of vulval and pelvic varices were studied. Diagnosis included physical examination, Doppler scan, duplex ultrasound scan, computed tomography, magnetic resonance imaging, and retrograde cinevideoangiography. The symptoms were classified as: 1, mild (n = 15); 2, moderately severe (n = 19); and 3, severe (n = 23). Group 1 was treated with sclerotherapy/local excision of vulval varices. Group 2 had gonadal vein resection (GVR; n = 12) and sclerotherapy or gonadal vein coil embolization (GVE; n = 7) and sclerotherapy. Only the incompetent side was treated. Patients in group 3 with isolated hypogastric vein tributary reflux were treated either with hypogastric vein tributaries division (HVTD) or with embolization (HVTE) as the only procedure. Those with combined gonadal and hypogastric vein reflux were treated with HVTE followed by GVR. The follow-up period ranged from 2.5 to 24 years (mean GVR/HVTD, 12.4 years; mean GVE/HVTE, 2.3 years). Pain improvement was assessed with a visual analog scale and through mailed questionnaires (response rate, 100%). Patient results were classified as excellent (asymptomatic), moderate (mild discomfort), or no improvement.

RESULTS

In group 1, 12 patients had excellent results and three had moderate results. In group 2, 10 patients treated with GVR had excellent results, one had moderate results, and one had no improvement. Three patients treated with GVE were asymptomatic, and four had no improvement. In group 3, three patients treated with HVTD were asymptomatic and two had no improvement. Five patients treated with HVTE were asymptomatic, and one had no improvement. Of the 12 patients treated with HVTE and GVR, 10 were asymptomatic, one had moderate results, and one had no improvement.

CONCLUSION

Local excision of vulval varices and sclerotherapy were sufficient in patients with mild symptoms. Gonadal vein excision produced better results than GVE. In patients with isolated hypogastric vein reflux, embolization was a better option than surgical treatment. GVR preceded by embolization of the incompetent tributaries of the internal iliac vein was indicated in patients with combined reflux and severe symptoms. Supplemental sclerotherapy of vulval varices is recommended after control of the intrapelvic reflux.

The nutcracker syndrome: its role in the pelvic venous disorders

BACKGROUND

Symptoms of pelvic venous congestion (chronic pelvic pain, dyspareunia, dysuria, and dysmenorrhea) have been attributed to massive gonadal reflux. However, obstruction of the gonadal outflow may produce similar symptoms. Mesoaortic compression of the left renal vein (nutcracker syndrome) produces both obstruction and reflux, resulting in symptoms of pelvic congestion. We describe the diagnosis and management of nine patients studied in our institutions.

MATERIALS AND METHODS

From a group of 51 female patients with pelvic congestion symptoms studied at our institutions, there were nine patients with symptoms of pelvic congestion, microscopic hematuria, and left-sided flank pain. The diagnosis of the nutcracker syndrome was suspected based on clinical examination, Doppler scan, duplex ultrasound scan, computed tomography scan, and magnetic resonance imaging. The diagnosis was confirmed by retrograde cine-video-angiography with renocaval gradient determination and catheterization of both internal iliac venous systems. All patients had a renocaval pressure gradient >4 mm Hg (normal, 0-1 mm Hg). Renal compression was relieved by external stent (ES) in two patients, internal stent (IS) in one patient, and gonadocaval bypass (GCB) in three. GCB was preceded by coil embolization of internal iliac vein tributaries connecting with lower-extremity varicose veins in three patients. Three patients deferred surgery and are under observation. Mean follow-up time was 36 months (range, 12-72 months).

RESULTS

Hematuria disappeared postoperatively in all patients. ES and IS normalized the renocaval gradient and resulted in significant alleviation of symptoms (90% improvement on a scale of 0-10 where 0 = no improvement and 10 = greatest improvement). Two patients with GCB had a residual gradient of 3 mm Hg. The third patient normalized the gradient. In this group, improvement of symptoms was 60%. Patients awaiting surgery are being treated conservatively (elastic stockings, hormones, and pelvic compression). They have shown only moderate improvement.

CONCLUSION

The nutcracker syndrome should be considered in women with symptoms of pelvic venous congestion and hematuria. The diagnosis is suspected by compression of the left renal vein on magnetic resonance imaging or computed tomography scan and confirmed by retrograde cine-video-angiography with determination of the renocaval gradient. Internal and external renal stenting as well as gonadocaval bypass are effective methods of treatment of the nutcracker syndrome. IS and ES were accompanied by better results than GCB. Surgical and radiologic interventional methods should be guided by the clinical, radiologic, and hemodynamic findings.

Facts and fiction surrounding the discovery of the venous valves

Venous valves are delicate structures, the integrity of which is crucial for the normal function of the venous system. Their abnormalities lead to widespread disorders, ranging from chronic venous insufficiency to life-threatening thromboembolic phenomena. The discovery of the venous valves, however, has been the subject of hot controversy. Even though Fabricius ab Aquapendente is credited with the discovery by most historians, we demonstrate in this paper that other anatomists described them many years before Fabricius ab Aquapendente publicly demonstrated them in Padua in 1579. A thorough review of the historical literature surrounding the discovery of the venous valves was carried out from 1545 to the present under the supervision of the Medical History Department of our institution. Research was performed at the History of Medicine Division of the National Library of Medicine and through MEDLINE access to the medical literature. The Parisian Charles Estienne first mentioned the venous valves in his 1545 publication when he described "apophyses membranarum" in the veins of the liver. Lusitanus and Canano publicly demonstrated them in the azygos vein during cadaver dissections performed in Ferrera, Italy. The Parisian Jacques Sylvius described valves in the veins of the extremities in 1555. The work of these anatomists, however, could not achieve full recognition, because Andreas Vesalius, the leading anatomist at that time, was unable to confirm their findings and strongly denied the existence of venous valves. Vesalius's influence was so powerful that research on the subject was idle until 1579, when Fabricius ab Aquapendente "discovered" the venous valves. About the same time, the German Salomon Alberti published the first drawings of a venous valve (in 1585). William Harvey, a disciple of Fabricius ab Aquapendente, finally postulated the function of the venous valves, providing anatomical support for one of the greatest discoveries in medicine: the blood circulation. Therefore, our investigations revealed that Estienne and Canano discovered the venous valves in the 1530s. Fabricius ab Aquapendente's achievement was their full recognition 64 years later. However, it was not until 1628 that their function was fully understood, with the discovery of the blood circulation by William Harvey.