Anatomic study of submandibular gland transfer in an attempt to prevent postradiation xerostomia

Submandibular Gland Transfer: A Potential Imaging Pitfall

BACKGROUND AND PURPOSE

The Seikaly and Jha submandibular gland transfer surgery is performed to facilitate gland shielding during radiation therapy for head and neck tumors to circumvent radiation-induced xerostomia. It results in an asymmetric postsurgical appearance of the submandibular and submental spaces. Our purpose was to characterize the morphologic and enhancement characteristics of the transferred submandibular gland and identify potential pitfalls in postoperative radiologic interpretation.

MATERIALS AND METHODS

This retrospective study identified patients with head and neck cancer who had undergone the submandibular gland transfer procedure at our institution. Chart reviews were performed to identify relevant oncologic histories and therapies. CT and MR neck imaging was reviewed to characterize morphologic and enhancement characteristics of the pre- and postoperative submandibular glands, as well as interpretive accuracy.

RESULTS

Eleven patients with oropharyngeal and nasopharyngeal squamous cell carcinomas who underwent submandibular gland transfer were identified. The transferred glands were significantly lengthened in the anteroposterior dimension compared with contralateral glands (P < .001) and displaced anteriorly and inferiorly within the submandibular and submental spaces. Enhancement patterns of the transferred submandibular glands varied, depending on the time of imaging relative to the operation and radiation therapy. Submandibular gland transfer was acknowledged in the postoperative report in 7/11 cases. Errors in interpretation were present in 2/11 reports.

CONCLUSIONS

After the submandibular gland transfer procedure, the submandibular and submental spaces lose their symmetric appearances as the transferred submandibular glands become lengthened and located more anteriorly and inferiorly, with variable enhancement characteristics. Familiarity with the postsurgical appearance of the transferred submandibular glands is key to accurate imaging interpretation.

Induction of Salivary Gland-Like Cells from Dental Follicle Epithelial Cells

The dental follicle (DF), most often associated with unerupted teeth, is a condensation of ectomesenchymal cells that surrounds the tooth germ in early stages of tooth development. In the present study, we aim to isolate epithelial stem-like cells from the human DF and explore their potential differentiation into salivary gland (SG) cells. We demonstrated the expression of stem cell-related genes in the epithelial components of human DF tissues, and these epithelial progenitor cells could be isolated and ex vivo expanded in a reproducible manner. The human DF-derived epithelial cells possessed clonogenic and sphere-forming capabilities, as well as expressed a panel of epithelial stem cell-related genes, thus conferring stem cell properties (hDF-EpiSCs). When cultured under in vitro 3-dimensional induction conditions, hDF-EpiSCs were capable to differentiate into SG acinar and duct cells. Furthermore, transplantation of hDF-EpiSC-loaded native de-cellularized rat parotid gland scaffolds into the renal capsule of nude mice led to the differentiation of transplanted hDF-EpiSCs into salivary gland-like cells. These findings suggest that hDF-EpiSCs might be a promising source of epithelial stem cells for the development of stem cell-based therapy or bioengineering SG tissues to repair/regenerate SG dysfunction.

Concise Review: Salivary Gland Regeneration: Therapeutic Approaches from Stem Cells to Tissue Organoids

The human salivary gland (SG) has an elegant architecture of epithelial acini, connecting ductal branching structures, vascular and neuronal networks that together function to produce and secrete saliva. This review focuses on the translation of cell- and tissue-based research toward therapies for patients suffering from SG hypofunction and related dry mouth syndrome (xerostomia), as a consequence of radiation therapy or systemic disease. We will broadly review the recent literature and discuss the clinical prospects of stem/progenitor cell and tissue-based therapies for SG repair and/or regeneration. Thus far, several strategies have been proposed for the purpose of restoring SG function: (1) transplanting autologous SG-derived epithelial stem/progenitor cells; (2) exploiting nonepithelial cells and/or their bioactive lysates; and (3) tissue engineering approaches using 3D (three-dimensional) biomaterials loaded with SG cells and/or bioactive cues to mimic in vivo SGs. We predict that further scientific improvement in each of these areas will translate to effective therapies toward the repair of damaged glands and the development of miniature SG organoids for the fundamental restoration of saliva secretion.

Submandibular salivary gland transfer for the prevention of radiation-induced xerostomia in patients with nasopharyngeal carcinoma: 5-Year outcomes

BACKGROUND

Our aim in this study was to investigate the value of the submandibular salivary gland transfer procedure in prevention of radiation-induced xerostomia in patients with nasopharyngeal carcinoma (NPC).

METHODS

In all, there were 70 patients, consisting of a test group (36 patients) and a control group (34 patients) in a nonrandomized fashion. In the test group, the submandibular salivary gland was transferred to submental space before radiotherapy (XRT) and shielded. Salivary gland functions were evaluated by the amount of saliva and a quality of life questionnaire before and after XRT and 3 and 60 months after XRT.

RESULTS

At 5 years, the trapping and excretion functions of salivary gland were significantly better in the test group (p = .000 and p = .000). The mean weight of saliva after XRT was heavier (1.65 g vs 0.73 g, p = .000), and the incidence of xerostomia was lower in the test group, with no difference in 5-year survival and neck nodal recurrence between the 2 groups.

CONCLUSIONS

Salivary gland transfer procedure prevents XRT-induced xerostomia and improves quality of life of patients with NPC.

Otorhinolaryngological and esophageal manifestations of epidermolysis bullosa

Epidermolysis bullosa (EB) is a group of skin diseases with different clinical manifestations and varied inheritance patterns. Blisters may appear spontaneously or following minimal trauma to the skin or mucosa.

Aim

this paper aims to describe the otorhinolaryngological manifestations and esophageal complications related to EB, and the experience in treating patients with esophageal stenosis secondary to this disease.

Materials and method

this descriptive study enrolled 60 patients with EB seen from June 1999 to December 2006 at the Head and Neck Surgery Service of X Hospital, a reference center for EB.

Results

the patients’ mean age was 14.5 years. Twenty-eight (46.6%) were females and 32 (53.4%) were males. Eight (13.4%) were diagnosed with epidermolysis bullosa simplex, while 51 (85%) had epidermolysis bullosa dystrophica; one (1.6%) patient had one acquired EB. Lips, mouth, tongue and ears were the most frequently involved sites (32 patients - 53.3%). Dysphagia was found in 28 patients (46.6%). After esophageal dilatation the symptoms subsided.

Conclusion

EB is a rare disease and patients must be sent for treatment at reference centers. Physicians treating patients for EB must be aware of the measures required to improve the quality of the treatment provided without putting the patients in harm’s way.

Transplantation of vascularized submandibular gland in dogs

PURPOSE

Presently, treatments for xerostomia only target symptoms, as an active therapy method has not been established. Herein, we discuss the possibility of using a submandibular gland allograft technique for the disease.

MATERIALS AND METHODS

Using a vascularized submandibular gland transplantation method, we extracted portions of the submandibular gland, including the duct and chorda tympani branches, from beagle dogs and placed them into the submental region of age- and weight-matched dogs. We then measured the amount of saliva secretion and examined the grafted glands histologically.

RESULTS

Sufficient quantities of saliva were secreted from the grafted glands with pilocarpine treatment. Histologic findings showed that the acinar cells in the grafted and untreated contralateral glands had some atrophy, as compared with the normal glands; however, periodic acid Schiff staining showed that they produced saliva.

CONCLUSIONS

Transplantation of vascularized submandibular glands into dogs was successful and may become a novel treatment strategy for patients with xerostomia.

Análise microscópica do efeito da radioterapia fracionada em glândula submandibular de rato

OBJETIVO: O estudo teve por objetivo avaliar, quantitativamente, as alterações histológicas induzidas pela radioterapia sobre o parênquima e o estroma da glândula submandibular. MATERIAIS E MÉTODOS: A amostra foi constituída por 30 ratos Wistar, distribuídos em dois grupos: teste e controle. Os 15 animais do grupo-teste foram submetidos a radioterapia da região de cabeça e pescoço, na modalidade fracionada rotacional por cobalto-60, na dose de 60 Gy, realizada em frações de 2 Gy diários, por seis semanas. Decorridas 60 horas da conclusão da radioterapia, as glândulas submandibulares dos animais de ambos os grupos foram excisadas, processadas pela técnica da parafina, coradas com hematoxilina e eosina e analisadas à microscopia óptica. O volume proporcional médio correspondente ao parênquima e ao estroma glandulares foi obtido pelo método estereológico de contagem manual de pontos. RESULTADOS: O volume proporcional de ácinos no grupo irradiado (60,67% ± 6,43) foi significativamente menor que no grupo-controle (67,42% ± 10,90) (p = 0,048), entretanto, não houve diferença estatisticamente significativa entre os grupos para as variáveis parênquima, ductos e estroma (teste t de Student, p > 0,05). CONCLUSÃO: O esquema radioterápico empregado provocou atrofia acinar da glândula submandibular, sem, no entanto, ocorrer alteração quantitativa total do estroma ou do parênquima.

Reduktion akuter radiogener Schädigungen durch Natriumselenit

BACKGROUND

In vitro studies show that sodium selenite is a potential radioprotector in normal cell cultures, but not tumor cells. The aim of this study was to evaluate the cytoprotective potency of sodium selenite during conventional fractionated irradiation of rat salivary glands, but also on tumor response and metastasis frequency of rhabdomyosarcomas R1H.

METHOD

The head-neck area of male WAG/RijH rats and the tumor in the flank were irradiated with (60)Co-gamma-rays (60 Gy/30 fractions/6 weeks). Sodium selenite (15 microg/kg body weight) was applied through a venous port 30 min before irradiation. Rats of a control group were treated in the same manner with an equal volume of physiologic sodium chloride. In the course of treatment the salivary glands were extirpated at different stages and examined histopathologically. The evaluation of the gland function was performed prior to and after radiotherapy by sialoscintigraphy. Tumor volume was measured during irradiation and plotted in tumor-volume curves. Rat body weight was determined sequentially to estimate the general constitution of the animal during the treatment.

RESULTS

Irradiation caused dose-dependent damage in the salivary glands. Intra- and intercellular edema (16 Gy), vacuolization (30 Gy), degranulation (46 Gy), and necrosis of the acinar cells (60 Gy) occurred. Sodium selenite delayed the development of the described damage, and the amount of necrotic acinar cells after the application of 60 Gy was reduced (control: 75% vs sodium selenite 30%), confirmed by the sialoscintigraphic results. The loss in gland function in the control group was 44% vs 74% (p<0.05) in the sodium selenite group. Sodium selenite had no influence on the response of R1H tumors to radiation and general constitution.

CONCLUSIONS

Based on morphological and sialoscintigraphic findings, a cytoprotective effect on acute toxicity of rat salivary glands could be detected under irradiation with synchronous application of sodium selenite. In addition, no effects on tumor response and metastasis frequency were observed. The general animal constitution was not affected by additional medication with sodium selenite during irradiation.