John R. Hyngstrom

Cardiac, skeletal, and smooth muscle mitochondrial respiration: are all mitochondria created equal?

Unlike cardiac and skeletal muscle, little is known about vascular smooth muscle mitochondrial respiration. Therefore, the present study examined mitochondrial respiratory rates in smooth muscle of healthy human feed arteries and compared with that of healthy cardiac and skeletal muscles. Cardiac, skeletal, and smooth muscles were harvested from a total of 22 subjects (53 ± 6 yr), and mitochondrial respiration was assessed in permeabilized fibers. Complex I + II, state 3 respiration, an index of oxidative phosphorylation capacity, fell progressively from cardiac to skeletal to smooth muscles (54 ± 1, 39 ± 4, and 15 ± 1 pmol·s(-1)·mg(-1), P < 0.05, respectively). Citrate synthase (CS) activity, an index of mitochondrial density, also fell progressively from cardiac to skeletal to smooth muscles (222 ± 13, 115 ± 2, and 48 ± 2 μmol·g(-1)·min(-1), P < 0.05, respectively). Thus, when respiration rates were normalized by CS (respiration per mitochondrial content), oxidative phosphorylation capacity was no longer different between the three muscle types. Interestingly, complex I state 2 normalized for CS activity, an index of nonphosphorylating respiration per mitochondrial content, increased progressively from cardiac to skeletal to smooth muscles, such that the respiratory control ratio, state 3/state 2 respiration, fell progressively from cardiac to skeletal to smooth muscles (5.3 ± 0.7, 3.2 ± 0.4, and 1.6 ± 0.3 pmol·s(-1)·mg(-1), P < 0.05, respectively). Thus, although oxidative phosphorylation capacity per mitochondrial content in cardiac, skeletal, and smooth muscles suggest all mitochondria are created equal, the contrasting respiratory control ratio and nonphosphorylating respiration highlight the existence of intrinsic functional differences between these muscle mitochondria. This likely influences the efficiency of oxidative phosphorylation and could potentially alter ROS production.

Intraoperative radiation therapy for locally advanced primary and recurrent colorectal cancer: Ten-year institutional experience

We evaluated the role of intraoperative radiation therapy (IORT) during radical resection of locally advanced colorectal cancer (CRC).

Impact of age on the vasodilatory function of human skeletal muscle feed arteries

Although advancing age is often associated with attenuated skeletal muscle blood flow and skeletal muscle feed arteries (SMFAs) have been recognized to play a regulatory role in the vasculature, little is known about the impact of age on the vasodilatory capacity of human SMFAs. Therefore, endothelium-dependent and -independent vasodilation were assessed in SMFAs (diameter: 544 ± 63 μm) obtained from 24 (equally represented) young (33 ± 2 yr) and old (71 ± 2 yr) subjects in response to three stimuli: 1) flow-induced shear stress, 2) ACh, and 3) sodium nitropusside (SNP). Both assessments of endothelium-dependent vasodilation, flow (young subjects: 68 ± 1% and old subjects: 32 ± 7%) and ACh (young subjects: 92 ± 3% and old subjects: 73 ± 4%), were significantly blunted (P < 0.05) in SMFAs of old compared with young subjects, with no such age-related differences in endothelium-independent vasodilation (SNP). In response to an increase in flow-induced shear stress, vasodilation kinetics (time constant to reach 63% of the amplitude of the response: 55 ± 1 s in young subjects and 92 ± 7 s in old subjects) and endothelial nitric oxide synthase (eNOS) activation (phospho-eNOS(s1177)/total eNOS: 1.0 ± 0.1 in young subjects and 0.2 ± 0.1 in old subjects) were also significantly attenuated in old compared with young subjects (P < 0.05). Furthermore, the vessel superoxide concentration was greater in old subjects (old subjects: 3.9 ± 1.0 area under curve/mg and young subjects: 1.7 ± 0.1 area under the curve/mg, P < 0.05). These findings reveal that the endothelium-dependent vasodilatory capacity, including vasodilation kinetics but not smooth muscle function, of human SMFAs is blunted with age and may be due to free radicals. Given the potential regulatory role of SMFAs in skeletal muscle blood flow, these findings may explain, at least in part, the often observed attenuated perfusion of skeletal muscle with advancing age that may contribute to exercise intolerance in the elderly.

Prospective assessment of lymphedema incidence and lymphedema-associated symptoms following lymph node surgery for melanoma

We aimed to prospectively assess limb volume change (LVC) and associated symptoms in patients with melanoma undergoing sentinel lymph node biopsy and/or therapeutic lymph node dissection. Limb volume was measured preoperatively and postoperatively at 6 and 12 months using a perometer (1000 mol/l). LVC was calculated and used to define three groups: less than 5%, 5–10%, and greater than 10%. A 19-item lymphedema symptom questionnaire was administered at baseline, 6, and 12 months. One hundred and eighty-two patients were enrolled. Twelve months after axillary surgery, 9% had LVC 5–10% and 13% had LVC greater than 10%. Twelve months after inguinofemoral surgery, 10% had LVC 5–10% and 13% had LVC greater than 10%. There was a significant seven- to nine-fold increase in symptoms for patients with LVC greater than 10% compared with those with LVC less than 5% (P<0.05). On multivariate analysis, therapeutic lymph node dissection versus sentinel lymph node biopsy (odds ratio=3.18; P<0.01) and borderline significance for lower-extremity versus upper-extremity procedures (odds ratio=1.72; P=0.07) were associated with LVC greater than 5%. LVC greater than 5% is common at 12 months following nodal surgery for melanoma and is associated with symptoms. Informed consent for melanoma patients undergoing lymph node surgery should include a discussion of the risks of postoperative lymphedema.

A phase I study of intratumoral ipilimumab and interleukin-2 in patients with advanced melanoma

Purpose Intratumoral interleukin-2 (IL-2) is effective but does not generate systemic immunity. Intravenous ipilimumab produces durable clinical response in a minority of patients, with potentially severe toxicities. Circulating anti-tumor T cells activated by ipilimumab may differ greatly from tumor-infiltrating lymphocytes activated by intratumoral ipilimumab in phenotypes and functionality. The objective of this study was to primarily assess the safety of intratumoral ipilimumab/IL-2 combination and to obtain data on clinical efficacy. Results There was no dose limiting toxicity. While local response of injected lesions was observed in 67% patients (95% CI, 40%-93%), an abscopal response was seen in 89% (95% CI, 68%-100%). The overall response rate and clinical benefit rate by immune-related response criteria (irRC) was 40% (95% CI, 10%-70%) and 50% (95% CI, 19%-81%), respectively. Enhanced systemic immune response was observed in most patients and correlated with clinical responses. Experimental Design Twelve patients with unresectable stages III/IV melanoma were enrolled. A standard 3+3 design was employed to assess highest tolerable intratumoral dose of ipilimumab and IL-2 based on toxicity during the first three weeks. Escalated doses of ipilimumab was injected into only one lesion weekly for eight weeks in cohorts of three patients. A fixed dose of IL-2 was injected three times a week into the same lesion for two weeks, followed by two times a week for six weeks. Conclusions Intratumoral injection with the combination of ipilimumab/IL-2 is well tolerated and generates responses in both injected and non-injected lesions in the majority of patients.

Age-related endothelial dysfunction in human skeletal muscle feed arteries: The role of free radicals derived from mitochondria in the vasculature

This study sought to determine the role of free radicals derived from mitochondria in the vasculature in the recognized age‐related endothelial dysfunction of human skeletal muscle feed arteries (SMFAs).

Adequacy of 5-mm surgical excision margins for non-lentiginous melanoma in situ.

To the Editor: The lentigo maligna (LM) subtype of melanoma-in-situ (MIS) develops on chronically sun-exposed skin, with indistinct clinical margins corresponding to single melanocytes trailing along the epidermal-dermal junction (Figure 1A,C,E). Alternatively, the less common non-lentiginous MIS (non-LM MIS) typically occurs in more sun-protected areas with distinct clinical margins corresponding to sharp transition from malignant to normal melanocytes histologically (Figure 1B,D,F). Fig 1 Clinical and histologic photographs of LM and non-LM-MIS. A, Clinical lesion of LM and B, Clinical lesion of non-LM-MIS contrast the relatively indistinct versus distinct clinical margins in these subtypes of MIS. C, Histology of LM demonstrates the lentiginous ... Treatment of MIS has historically been surgical excision with 5-mm margins, however a footnote added in the recent NCCN guidelines indicates that some MIS (i.e. LM) require greater margins to ensure removal and prevent local recurrence.1 Based on their review of MIS lesions treated by Mohs surgery and finding that 14% required a margin of > 6 mm for histologic clearance, Kunishige et al.2 recommended 9-mm margins for standard excision of MIS. Appropriate surgical margins for non-LM MIS using standard excision technique have not been rigorously defined,3 and treating all MIS with 9-mm excisional margins as proposed2 may lead to larger than necessary excisions for non-LM MIS. We initiated an IRB-approved study (RONMIST: Review of non-lentiginous melanoma-in-situ lesions treated) to determine histologic margins and recurrence rates of non-LM-MIS treated by standard excision at our institution. From the University of Utah Dermatology dermatopathology (1990–2010) and Huntsman Cancer Institute Melanoma Program (2000–2010) databases, we identified 268 unique cases reported as non-LM-MIS. Matching biopsy and excision slides were obtained for 81 cases, which were reviewed in blinded fashion by board-certified dermatopathologists (KLD, SRF, ARB) to assess accuracy of initial diagnosis and confirm non-LM MIS. Only 36 biopsies were confirmed as non-LM MIS (Table I). Among the excluded cases, most (40/45) were deemed LM and not non-LM MIS. The biopsy margins were positive in only 16 specimens (11 shaves, 5 punches), and in none of the 6 excisional biopsies. Only 3 of the 16 (19%) biopsy specimens with positive margins demonstrated residual melanoma on re-excision, and none of the specimens with negative biopsy margins demonstrated residual tumor on re-excision. The average histologic excisional margin was 3.80 mm (range 0.2 – 6.5 mm). While our practice is to excise these lesions with 5-mm margins, our data suggests that often the clinical margins are < 5 mm even after normal shrinkage (approximately 15%) from formalin processing is accounted for. The average margin of clearance was 4.38 mm (range 1.30 – 7.75 mm). Table I Histologic margin assessment of non-LM-MIS cases in this study. As summarized in Table II, these lesions were confined to the trunk or extremities and had a median size of 7 mm (range 2–18). Of 34 patients with confirmed follow-up (0.5 to 18 years, median 6.6 years), none had clinical evidence of recurrence. Follow-up times were short for some patients who were seen shortly after surgery and then never returned for additional follow-up. Table II Demographic and clinical information for patients with non-LM-MIS in this study. Most prior studies of MIS did not distinguish between LM and non-LM MIS subtypes. In response to our correspondence,3 Kunishige et al.4 re-analyzed a subset of their cases and reported that 17 of 91 (19%) “other MIS” (non-LM) cases required > 6-mm margins for histologic clearance. A possible explanation for this discrepancy in margin requirements between their study and ours is that some of their “other MIS” lesions may have been LM rather than non-LM MIS. Distinguishing between these two entities on frozen sections is problematic due to freeze artifact, and they do not appear to have re-reviewed permanent paraffin-embedded sections to confirm diagnoses as we did in the present study. We were able to distinguish clearly between these two MIS subtypes upon histologic examination. Our results are consistent with a recent study by Akhtar et al.5 in which 192 cases of MIS (62% were non-LM MIS) were examined; no recurrence of non-LM MIS lesions was found and most were excised with margins of 2–5 mm. In conclusion, LM and non-LM MIS are distinct entities clinically, histologically, and molecularly – thus their optimal treatment is not the same. Based on our findings, we suggest that 5-mm margins are adequate for standard excision of lesions clinically and histologically consistent with non-LM MIS.

Melanoma sentinel-node metastasis

To the Editor: In the landmark second Multicenter Selective Lymphadenectomy Trial (MSLT-II), Faries et al. (June 8 issue)1 report that among patients with melanoma and sentinel-node metastases, completion lymph-node dissection increased the rate of regional disease control and provided prognostic information but did not improve melanoma-specific survival. The next step is to determine how to incorporate the MSLT-II results into practice and clinical guidelines. Initial reactions may be to avoid completion lymph-node dissection in all patients with positive sentinel nodes. However, the patients in this trial were a highly selected group with an extremely low burden of sentinel-node disease. The median tumor burden was approximately 0.65 mm, and approximately 70% of the patients had only one involved node. Even in this highly selected group, there were differences in the regional recurrence rate, and it would follow that patients with more sentinel-node tumor burden or more positive nodes would have an even higher rate of involvement of nonsentinel lymph nodes, which would lead to increased rates of regional recurrence. Such an increase may presumably have an adverse effect on melanomaspecific survival in patients who did not undergo completion lymph-node dissection. MSLT-II is “practice confirming,”2 since patients with extremely low burden sentinel-node disease have often already been forgoing completion lymph-node dissection.3 However, the results of this trial should not be blindly extrapolated to all patients who have a greater volume of sentinel-node disease than the group represented in MLST-II. Continued monitoring of practice patterns is needed to ensure that the trial findings are not extended to inappropriate populations. Karl Y. Bilimoria, M.D., M.S.C.I.

Risk factors for development of melanoma brain metastasis and disease progression: A single-center retrospective analysis

Melanoma metastasis to the brain is associated with a poor prognosis. We sought to determine patient demographics and primary tumor factors associated with the development of brain metastasis (BM) and survival. We also investigated whether the BM detection setting (routine screening vs. symptomatic presentation) affected clinical outcomes. A database of melanoma patients seen from 1999 to 2015 at our institution was reviewed to identify patients who developed BM. Patients with BM were matched by initial stage with patients who did not develop BM as a control group. Patient demographics, primary tumor characteristics, and clinical outcomes were analyzed. A total of 123 patients with BM were matched by initial presenting stage to 237 patients without BM. The characteristics of the primary melanoma tumor associated with BM development included location on the scalp (P=0.030), nodular histologic type (P=0.020), and Breslow depth more than 4 mm (P=0.048), whereas location on the leg was associated with decreased BM risk (P=0.006). In patients with BM, time to first recurrence for melanomas of the scalp was significantly shorter (10.8 vs. 24.8 months, P=0.007) than nonscalp head and neck tumors. Patient stage, tumor depth, nodular type, and ulceration were also associated with worse clinical outcomes. There were no differences in the clinical outcomes between patients whose BM were detected upon routine screening versus those detected upon symptomatic presentation. In summary, factors predictive of development of BM included primary scalp location, nodular type, and depth. In BM patients, scalp location, stage, tumor depth, nodular type, and ulceration, but not detection setting, were associated with worse clinical outcomes.

TRPV1 channels in human skeletal muscle feed arteries: implications for vascular function

What is the central question of this study? We sought to determine whether human skeletal muscle feed arteries (SFMAs) express TRPV1 channels and what role they play in modulating vascular function. What is the main finding and its importance? Human SMFAs do express functional TRPV1 channels that modulate vascular function, specifically opposing α‐adrenergic receptor‐mediated vasocontraction and potentiating vasorelaxation, in an endothelium‐dependent manner, as evidenced by the α1‐receptor‐mediated responses. Thus, the vasodilatory role of TRPV1 channels, and their ligand capsaicin, could be a potential therapeutic target for improving vascular function. Additionally, given the ‘sympatholytic’ effect of TRPV1 activation and known endogenous activators (anandamide, reactive oxygen species, H+, etc.), TRPV1 channels might contribute to functional sympatholysis during exercise.